--- /dev/null
+;;; undo-tree.el --- Treat undo history as a tree -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2009-2014 Free Software Foundation, Inc
+
+;; Author: Toby Cubitt <toby-undo-treeNOSPAMdr-qubit.org>
+;; Version: 0.6.6
+;; Package-Version: 20140509.522
+;; Keywords: convenience, files, undo, redo, history, tree
+;; URL: http://www.dr-qubit.org/emacs.php
+;; Repository: http://www.dr-qubit.org/git/undo-tree.git
+
+;; This file is part of Emacs.
+;;
+;; This file is free software: you can redistribute it and/or modify it under
+;; the terms of the GNU General Public License as published by the Free
+;; Software Foundation, either version 3 of the License, or (at your option)
+;; any later version.
+;;
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+;; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+;; more details.
+;;
+;; You should have received a copy of the GNU General Public License along
+;; with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
+
+
+;;; Commentary:
+;;
+;; Emacs has a powerful undo system. Unlike the standard undo/redo system in
+;; most software, it allows you to recover *any* past state of a buffer
+;; (whereas the standard undo/redo system can lose past states as soon as you
+;; redo). However, this power comes at a price: many people find Emacs' undo
+;; system confusing and difficult to use, spawning a number of packages that
+;; replace it with the less powerful but more intuitive undo/redo system.
+;;
+;; Both the loss of data with standard undo/redo, and the confusion of Emacs'
+;; undo, stem from trying to treat undo history as a linear sequence of
+;; changes. It's not. The `undo-tree-mode' provided by this package replaces
+;; Emacs' undo system with a system that treats undo history as what it is: a
+;; branching tree of changes. This simple idea allows the more intuitive
+;; behaviour of the standard undo/redo system to be combined with the power of
+;; never losing any history. An added side bonus is that undo history can in
+;; some cases be stored more efficiently, allowing more changes to accumulate
+;; before Emacs starts discarding history.
+;;
+;; The only downside to this more advanced yet simpler undo system is that it
+;; was inspired by Vim. But, after all, most successful religions steal the
+;; best ideas from their competitors!
+;;
+;;
+;; Installation
+;; ============
+;;
+;; This package has only been tested with Emacs versions 24 and CVS. It should
+;; work in Emacs versions 22 and 23 too, but will not work without
+;; modifications in earlier versions of Emacs.
+;;
+;; To install `undo-tree-mode', make sure this file is saved in a directory in
+;; your `load-path', and add the line:
+;;
+;; (require 'undo-tree)
+;;
+;; to your .emacs file. Byte-compiling undo-tree.el is recommended (e.g. using
+;; "M-x byte-compile-file" from within emacs).
+;;
+;; If you want to replace the standard Emacs' undo system with the
+;; `undo-tree-mode' system in all buffers, you can enable it globally by
+;; adding:
+;;
+;; (global-undo-tree-mode)
+;;
+;; to your .emacs file.
+;;
+;;
+;; Quick-Start
+;; ===========
+;;
+;; If you're the kind of person who likes to jump in the car and drive,
+;; without bothering to first figure out whether the button on the left dips
+;; the headlights or operates the ejector seat (after all, you'll soon figure
+;; it out when you push it), then here's the minimum you need to know:
+;;
+;; `undo-tree-mode' and `global-undo-tree-mode'
+;; Enable undo-tree mode (either in the current buffer or globally).
+;;
+;; C-_ C-/ (`undo-tree-undo')
+;; Undo changes.
+;;
+;; M-_ C-? (`undo-tree-redo')
+;; Redo changes.
+;;
+;; `undo-tree-switch-branch'
+;; Switch undo-tree branch.
+;; (What does this mean? Better press the button and see!)
+;;
+;; C-x u (`undo-tree-visualize')
+;; Visualize the undo tree.
+;; (Better try pressing this button too!)
+;;
+;; C-x r u (`undo-tree-save-state-to-register')
+;; Save current buffer state to register.
+;;
+;; C-x r U (`undo-tree-restore-state-from-register')
+;; Restore buffer state from register.
+;;
+;;
+;;
+;; In the undo-tree visualizer:
+;;
+;; <up> p C-p (`undo-tree-visualize-undo')
+;; Undo changes.
+;;
+;; <down> n C-n (`undo-tree-visualize-redo')
+;; Redo changes.
+;;
+;; <left> b C-b (`undo-tree-visualize-switch-branch-left')
+;; Switch to previous undo-tree branch.
+;;
+;; <right> f C-f (`undo-tree-visualize-switch-branch-right')
+;; Switch to next undo-tree branch.
+;;
+;; C-<up> M-{ (`undo-tree-visualize-undo-to-x')
+;; Undo changes up to last branch point.
+;;
+;; C-<down> M-} (`undo-tree-visualize-redo-to-x')
+;; Redo changes down to next branch point.
+;;
+;; <down> n C-n (`undo-tree-visualize-redo')
+;; Redo changes.
+;;
+;; <mouse-1> (`undo-tree-visualizer-mouse-set')
+;; Set state to node at mouse click.
+;;
+;; t (`undo-tree-visualizer-toggle-timestamps')
+;; Toggle display of time-stamps.
+;;
+;; d (`undo-tree-visualizer-toggle-diff')
+;; Toggle diff display.
+;;
+;; s (`undo-tree-visualizer-selection-mode')
+;; Toggle keyboard selection mode.
+;;
+;; q (`undo-tree-visualizer-quit')
+;; Quit undo-tree-visualizer.
+;;
+;; C-q (`undo-tree-visualizer-abort')
+;; Abort undo-tree-visualizer.
+;;
+;; , <
+;; Scroll left.
+;;
+;; . >
+;; Scroll right.
+;;
+;; <pgup> M-v
+;; Scroll up.
+;;
+;; <pgdown> C-v
+;; Scroll down.
+;;
+;;
+;;
+;; In visualizer selection mode:
+;;
+;; <up> p C-p (`undo-tree-visualizer-select-previous')
+;; Select previous node.
+;;
+;; <down> n C-n (`undo-tree-visualizer-select-next')
+;; Select next node.
+;;
+;; <left> b C-b (`undo-tree-visualizer-select-left')
+;; Select left sibling node.
+;;
+;; <right> f C-f (`undo-tree-visualizer-select-right')
+;; Select right sibling node.
+;;
+;; <pgup> M-v
+;; Select node 10 above.
+;;
+;; <pgdown> C-v
+;; Select node 10 below.
+;;
+;; <enter> (`undo-tree-visualizer-set')
+;; Set state to selected node and exit selection mode.
+;;
+;; s (`undo-tree-visualizer-mode')
+;; Exit selection mode.
+;;
+;; t (`undo-tree-visualizer-toggle-timestamps')
+;; Toggle display of time-stamps.
+;;
+;; d (`undo-tree-visualizer-toggle-diff')
+;; Toggle diff display.
+;;
+;; q (`undo-tree-visualizer-quit')
+;; Quit undo-tree-visualizer.
+;;
+;; C-q (`undo-tree-visualizer-abort')
+;; Abort undo-tree-visualizer.
+;;
+;; , <
+;; Scroll left.
+;;
+;; . >
+;; Scroll right.
+;;
+;;
+;;
+;; Persistent undo history:
+;;
+;; Note: Requires Emacs version 24.3 or higher.
+;;
+;; `undo-tree-auto-save-history' (variable)
+;; automatically save and restore undo-tree history along with buffer
+;; (disabled by default)
+;;
+;; `undo-tree-save-history' (command)
+;; manually save undo history to file
+;;
+;; `undo-tree-load-history' (command)
+;; manually load undo history from file
+;;
+;;
+;;
+;; Compressing undo history:
+;;
+;; Undo history files cannot grow beyond the maximum undo tree size, which
+;; is limited by `undo-limit', `undo-strong-limit' and
+;; `undo-outer-limit'. Nevertheless, undo history files can grow quite
+;; large. If you want to automatically compress undo history, add the
+;; following advice to your .emacs file (replacing ".gz" with the filename
+;; extension of your favourite compression algorithm):
+;;
+;; (defadvice undo-tree-make-history-save-file-name
+;; (after undo-tree activate)
+;; (setq ad-return-value (concat ad-return-value ".gz")))
+;;
+;;
+;;
+;;
+;; Undo Systems
+;; ============
+;;
+;; To understand the different undo systems, it's easiest to consider an
+;; example. Imagine you make a few edits in a buffer. As you edit, you
+;; accumulate a history of changes, which we might visualize as a string of
+;; past buffer states, growing downwards:
+;;
+;; o (initial buffer state)
+;; |
+;; |
+;; o (first edit)
+;; |
+;; |
+;; o (second edit)
+;; |
+;; |
+;; x (current buffer state)
+;;
+;;
+;; Now imagine that you undo the last two changes. We can visualize this as
+;; rewinding the current state back two steps:
+;;
+;; o (initial buffer state)
+;; |
+;; |
+;; x (current buffer state)
+;; |
+;; |
+;; o
+;; |
+;; |
+;; o
+;;
+;;
+;; However, this isn't a good representation of what Emacs' undo system
+;; does. Instead, it treats the undos as *new* changes to the buffer, and adds
+;; them to the history:
+;;
+;; o (initial buffer state)
+;; |
+;; |
+;; o (first edit)
+;; |
+;; |
+;; o (second edit)
+;; |
+;; |
+;; x (buffer state before undo)
+;; |
+;; |
+;; o (first undo)
+;; |
+;; |
+;; x (second undo)
+;;
+;;
+;; Actually, since the buffer returns to a previous state after an undo,
+;; perhaps a better way to visualize it is to imagine the string of changes
+;; turning back on itself:
+;;
+;; (initial buffer state) o
+;; |
+;; |
+;; (first edit) o x (second undo)
+;; | |
+;; | |
+;; (second edit) o o (first undo)
+;; | /
+;; |/
+;; o (buffer state before undo)
+;;
+;; Treating undos as new changes might seem a strange thing to do. But the
+;; advantage becomes clear as soon as we imagine what happens when you edit
+;; the buffer again. Since you've undone a couple of changes, new edits will
+;; branch off from the buffer state that you've rewound to. Conceptually, it
+;; looks like this:
+;;
+;; o (initial buffer state)
+;; |
+;; |
+;; o
+;; |\
+;; | \
+;; o x (new edit)
+;; |
+;; |
+;; o
+;;
+;; The standard undo/redo system only lets you go backwards and forwards
+;; linearly. So as soon as you make that new edit, it discards the old
+;; branch. Emacs' undo just keeps adding changes to the end of the string. So
+;; the undo history in the two systems now looks like this:
+;;
+;; Undo/Redo: Emacs' undo
+;;
+;; o o
+;; | |
+;; | |
+;; o o o
+;; .\ | |\
+;; . \ | | \
+;; . x (new edit) o o |
+;; (discarded . | / |
+;; branch) . |/ |
+;; . o |
+;; |
+;; |
+;; x (new edit)
+;;
+;; Now, what if you change your mind about those undos, and decide you did
+;; like those other changes you'd made after all? With the standard undo/redo
+;; system, you're lost. There's no way to recover them, because that branch
+;; was discarded when you made the new edit.
+;;
+;; However, in Emacs' undo system, those old buffer states are still there in
+;; the undo history. You just have to rewind back through the new edit, and
+;; back through the changes made by the undos, until you reach them. Of
+;; course, since Emacs treats undos (even undos of undos!) as new changes,
+;; you're really weaving backwards and forwards through the history, all the
+;; time adding new changes to the end of the string as you go:
+;;
+;; o
+;; |
+;; |
+;; o o o (undo new edit)
+;; | |\ |\
+;; | | \ | \
+;; o o | | o (undo the undo)
+;; | / | | |
+;; |/ | | |
+;; (trying to get o | | x (undo the undo)
+;; to this state) | /
+;; |/
+;; o
+;;
+;; So far, this is still reasonably intuitive to use. It doesn't behave so
+;; differently to standard undo/redo, except that by going back far enough you
+;; can access changes that would be lost in standard undo/redo.
+;;
+;; However, imagine that after undoing as just described, you decide you
+;; actually want to rewind right back to the initial state. If you're lucky,
+;; and haven't invoked any command since the last undo, you can just keep on
+;; undoing until you get back to the start:
+;;
+;; (trying to get o x (got there!)
+;; to this state) | |
+;; | |
+;; o o o o (keep undoing)
+;; | |\ |\ |
+;; | | \ | \ |
+;; o o | | o o (keep undoing)
+;; | / | | | /
+;; |/ | | |/
+;; (already undid o | | o (got this far)
+;; to this state) | /
+;; |/
+;; o
+;;
+;; But if you're unlucky, and you happen to have moved the point (say) after
+;; getting to the state labelled "got this far", then you've "broken the undo
+;; chain". Hold on to something solid, because things are about to get
+;; hairy. If you try to undo now, Emacs thinks you're trying to undo the
+;; undos! So to get back to the initial state you now have to rewind through
+;; *all* the changes, including the undos you just did:
+;;
+;; (trying to get o x (finally got there!)
+;; to this state) | |
+;; | |
+;; o o o o o o
+;; | |\ |\ |\ |\ |
+;; | | \ | \ | \ | \ |
+;; o o | | o o o | o o
+;; | / | | | / | | | /
+;; |/ | | |/ | | |/
+;; (already undid o | | o<. | | o
+;; to this state) | / : | /
+;; |/ : |/
+;; o : o
+;; :
+;; (got this far, but
+;; broke the undo chain)
+;;
+;; Confused?
+;;
+;; In practice you can just hold down the undo key until you reach the buffer
+;; state that you want. But whatever you do, don't move around in the buffer
+;; to *check* that you've got back to where you want! Because you'll break the
+;; undo chain, and then you'll have to traverse the entire string of undos
+;; again, just to get back to the point at which you broke the
+;; chain. Undo-in-region and commands such as `undo-only' help to make using
+;; Emacs' undo a little easier, but nonetheless it remains confusing for many
+;; people.
+;;
+;;
+;; So what does `undo-tree-mode' do? Remember the diagram we drew to represent
+;; the history we've been discussing (make a few edits, undo a couple of them,
+;; and edit again)? The diagram that conceptually represented our undo
+;; history, before we started discussing specific undo systems? It looked like
+;; this:
+;;
+;; o (initial buffer state)
+;; |
+;; |
+;; o
+;; |\
+;; | \
+;; o x (current state)
+;; |
+;; |
+;; o
+;;
+;; Well, that's *exactly* what the undo history looks like to
+;; `undo-tree-mode'. It doesn't discard the old branch (as standard undo/redo
+;; does), nor does it treat undos as new changes to be added to the end of a
+;; linear string of buffer states (as Emacs' undo does). It just keeps track
+;; of the tree of branching changes that make up the entire undo history.
+;;
+;; If you undo from this point, you'll rewind back up the tree to the previous
+;; state:
+;;
+;; o
+;; |
+;; |
+;; x (undo)
+;; |\
+;; | \
+;; o o
+;; |
+;; |
+;; o
+;;
+;; If you were to undo again, you'd rewind back to the initial state. If on
+;; the other hand you redo the change, you'll end up back at the bottom of the
+;; most recent branch:
+;;
+;; o (undo takes you here)
+;; |
+;; |
+;; o (start here)
+;; |\
+;; | \
+;; o x (redo takes you here)
+;; |
+;; |
+;; o
+;;
+;; So far, this is just like the standard undo/redo system. But what if you
+;; want to return to a buffer state located on a previous branch of the
+;; history? Since `undo-tree-mode' keeps the entire history, you simply need
+;; to tell it to switch to a different branch, and then redo the changes you
+;; want:
+;;
+;; o
+;; |
+;; |
+;; o (start here, but switch
+;; |\ to the other branch)
+;; | \
+;; (redo) o o
+;; |
+;; |
+;; (redo) x
+;;
+;; Now you're on the other branch, if you undo and redo changes you'll stay on
+;; that branch, moving up and down through the buffer states located on that
+;; branch. Until you decide to switch branches again, of course.
+;;
+;; Real undo trees might have multiple branches and sub-branches:
+;;
+;; o
+;; ____|______
+;; / \
+;; o o
+;; ____|__ __|
+;; / | \ / \
+;; o o o o x
+;; | |
+;; / \ / \
+;; o o o o
+;;
+;; Trying to imagine what Emacs' undo would do as you move about such a tree
+;; will likely frazzle your brain circuits! But in `undo-tree-mode', you're
+;; just moving around this undo history tree. Most of the time, you'll
+;; probably only need to stay on the most recent branch, in which case it
+;; behaves like standard undo/redo, and is just as simple to understand. But
+;; if you ever need to recover a buffer state on a different branch, the
+;; possibility of switching between branches and accessing the full undo
+;; history is still there.
+;;
+;;
+;;
+;; The Undo-Tree Visualizer
+;; ========================
+;;
+;; Actually, it gets better. You don't have to imagine all these tree
+;; diagrams, because `undo-tree-mode' includes an undo-tree visualizer which
+;; draws them for you! In fact, it draws even better diagrams: it highlights
+;; the node representing the current buffer state, it highlights the current
+;; branch, and you can toggle the display of time-stamps (by hitting "t") and
+;; a diff of the undo changes (by hitting "d"). (There's one other tiny
+;; difference: the visualizer puts the most recent branch on the left rather
+;; than the right.)
+;;
+;; Bring up the undo tree visualizer whenever you want by hitting "C-x u".
+;;
+;; In the visualizer, the usual keys for moving up and down a buffer instead
+;; move up and down the undo history tree (e.g. the up and down arrow keys, or
+;; "C-n" and "C-p"). The state of the "parent" buffer (the buffer whose undo
+;; history you are visualizing) is updated as you move around the undo tree in
+;; the visualizer. If you reach a branch point in the visualizer, the usual
+;; keys for moving forward and backward in a buffer instead switch branch
+;; (e.g. the left and right arrow keys, or "C-f" and "C-b").
+;;
+;; Clicking with the mouse on any node in the visualizer will take you
+;; directly to that node, resetting the state of the parent buffer to the
+;; state represented by that node.
+;;
+;; You can also select nodes directly using the keyboard, by hitting "s" to
+;; toggle selection mode. The usual motion keys now allow you to move around
+;; the tree without changing the parent buffer. Hitting <enter> will reset the
+;; state of the parent buffer to the state represented by the currently
+;; selected node.
+;;
+;; It can be useful to see how long ago the parent buffer was in the state
+;; represented by a particular node in the visualizer. Hitting "t" in the
+;; visualizer toggles the display of time-stamps for all the nodes. (Note
+;; that, because of the way `undo-tree-mode' works, these time-stamps may be
+;; somewhat later than the true times, especially if it's been a long time
+;; since you last undid any changes.)
+;;
+;; To get some idea of what changes are represented by a given node in the
+;; tree, it can be useful to see a diff of the changes. Hit "d" in the
+;; visualizer to toggle a diff display. This normally displays a diff between
+;; the current state and the previous one, i.e. it shows you the changes that
+;; will be applied if you undo (move up the tree). However, the diff display
+;; really comes into its own in the visualizer's selection mode (see above),
+;; where it instead shows a diff between the current state and the currently
+;; selected state, i.e. it shows you the changes that will be applied if you
+;; reset to the selected state.
+;;
+;; (Note that the diff is generated by the Emacs `diff' command, and is
+;; displayed using `diff-mode'. See the corresponding customization groups if
+;; you want to customize the diff display.)
+;;
+;; Finally, hitting "q" will quit the visualizer, leaving the parent buffer in
+;; whatever state you ended at. Hitting "C-q" will abort the visualizer,
+;; returning the parent buffer to whatever state it was originally in when the
+;; visualizer was .
+;;
+;;
+;;
+;; Undo-in-Region
+;; ==============
+;;
+;; Emacs allows a very useful and powerful method of undoing only selected
+;; changes: when a region is active, only changes that affect the text within
+;; that region will be undone. With the standard Emacs undo system, changes
+;; produced by undoing-in-region naturally get added onto the end of the
+;; linear undo history:
+;;
+;; o
+;; |
+;; | x (second undo-in-region)
+;; o |
+;; | |
+;; | o (first undo-in-region)
+;; o |
+;; | /
+;; |/
+;; o
+;;
+;; You can of course redo these undos-in-region as usual, by undoing the
+;; undos:
+;;
+;; o
+;; |
+;; | o_
+;; o | \
+;; | | |
+;; | o o (undo the undo-in-region)
+;; o | |
+;; | / |
+;; |/ |
+;; o x (undo the undo-in-region)
+;;
+;;
+;; In `undo-tree-mode', undo-in-region works much the same way: when there's
+;; an active region, undoing only undoes changes that affect that region. In
+;; `undo-tree-mode', redoing when there's an active region similarly only
+;; redoes changes that affect that region.
+;;
+;; However, the way these undo- and redo-in-region changes are recorded in the
+;; undo history is quite different. The good news is, you don't need to
+;; understand this to use undo- and redo-in-region in `undo-tree-mode' - just
+;; go ahead and use them! They'll probably work as you expect. But if you're
+;; masochistic enough to want to understand conceptually what's happening to
+;; the undo tree as you undo- and redo-in-region, then read on...
+;;
+;;
+;; Undo-in-region creates a new branch in the undo history. The new branch
+;; consists of an undo step that undoes some of the changes that affect the
+;; current region, and another step that undoes the remaining changes needed
+;; to rejoin the previous undo history.
+;;
+;; Previous undo history Undo-in-region
+;;
+;; o o
+;; | |
+;; | |
+;; | |
+;; o o
+;; | |
+;; | |
+;; | |
+;; o o_
+;; | | \
+;; | | x (undo-in-region)
+;; | | |
+;; x o o
+;;
+;; As long as you don't change the active region after undoing-in-region,
+;; continuing to undo-in-region extends the new branch, pulling more changes
+;; that affect the current region into an undo step immediately above your
+;; current location in the undo tree, and pushing the point at which the new
+;; branch is attached further up the tree:
+;;
+;; First undo-in-region Second undo-in-region
+;;
+;; o o
+;; | |
+;; | |
+;; | |
+;; o o_
+;; | | \
+;; | | x (undo-in-region)
+;; | | |
+;; o_ o |
+;; | \ | |
+;; | x | o
+;; | | | |
+;; o o o o
+;;
+;; Redoing takes you back down the undo tree, as usual (as long as you haven't
+;; changed the active region after undoing-in-region, it doesn't matter if it
+;; is still active):
+;;
+;; o
+;; |
+;; |
+;; |
+;; o_
+;; | \
+;; | o
+;; | |
+;; o |
+;; | |
+;; | o (redo)
+;; | |
+;; o x (redo)
+;;
+;;
+;; What about redo-in-region? Obviously, redo-in-region only makes sense if
+;; you have already undone some changes, so that there are some changes to
+;; redo! Redoing-in-region splits off a new branch of the undo history below
+;; your current location in the undo tree. This time, the new branch consists
+;; of a first redo step that redoes some of the redo changes that affect the
+;; current region, followed by *all* the remaining redo changes.
+;;
+;; Previous undo history Redo-in-region
+;;
+;; o o
+;; | |
+;; | |
+;; | |
+;; x o_
+;; | | \
+;; | | x (redo-in-region)
+;; | | |
+;; o o |
+;; | | |
+;; | | |
+;; | | |
+;; o o o
+;;
+;; As long as you don't change the active region after redoing-in-region,
+;; continuing to redo-in-region extends the new branch, pulling more redo
+;; changes into a redo step immediately below your current location in the
+;; undo tree.
+;;
+;; First redo-in-region Second redo-in-region
+;;
+;; o o
+;; | |
+;; | |
+;; | |
+;; o_ o_
+;; | \ | \
+;; | x | o
+;; | | | |
+;; o | o |
+;; | | | |
+;; | | | x (redo-in-region)
+;; | | | |
+;; o o o o
+;;
+;; Note that undo-in-region and redo-in-region only ever add new changes to
+;; the undo tree, they *never* modify existing undo history. So you can always
+;; return to previous buffer states by switching to a previous branch of the
+;; tree.
+
+
+
+;;; Code:
+
+(eval-when-compile (require 'cl))
+(require 'diff)
+
+
+\f
+;;; =====================================================================
+;;; Compatibility hacks for older Emacsen
+
+;; `characterp' isn't defined in Emacs versions < 23
+(unless (fboundp 'characterp)
+ (defalias 'characterp 'char-valid-p))
+
+;; `region-active-p' isn't defined in Emacs versions < 23
+(unless (fboundp 'region-active-p)
+ (defun region-active-p () (and transient-mark-mode mark-active)))
+
+
+;; `registerv' defstruct isn't defined in Emacs versions < 24
+(unless (fboundp 'registerv-make)
+ (defmacro registerv-make (data &rest _dummy) data))
+
+(unless (fboundp 'registerv-data)
+ (defmacro registerv-data (data) data))
+
+
+;; `diff-no-select' and `diff-file-local-copy' aren't defined in Emacs
+;; versions < 24 (copied and adapted from Emacs 24)
+(unless (fboundp 'diff-no-select)
+ (defun diff-no-select (old new &optional switches no-async buf)
+ ;; Noninteractive helper for creating and reverting diff buffers
+ (unless (bufferp new) (setq new (expand-file-name new)))
+ (unless (bufferp old) (setq old (expand-file-name old)))
+ (or switches (setq switches diff-switches)) ; If not specified, use default.
+ (unless (listp switches) (setq switches (list switches)))
+ (or buf (setq buf (get-buffer-create "*Diff*")))
+ (let* ((old-alt (diff-file-local-copy old))
+ (new-alt (diff-file-local-copy new))
+ (command
+ (mapconcat 'identity
+ `(,diff-command
+ ;; Use explicitly specified switches
+ ,@switches
+ ,@(mapcar #'shell-quote-argument
+ (nconc
+ (when (or old-alt new-alt)
+ (list "-L" (if (stringp old)
+ old (prin1-to-string old))
+ "-L" (if (stringp new)
+ new (prin1-to-string new))))
+ (list (or old-alt old)
+ (or new-alt new)))))
+ " "))
+ (thisdir default-directory))
+ (with-current-buffer buf
+ (setq buffer-read-only t)
+ (buffer-disable-undo (current-buffer))
+ (let ((inhibit-read-only t))
+ (erase-buffer))
+ (buffer-enable-undo (current-buffer))
+ (diff-mode)
+ (set (make-local-variable 'revert-buffer-function)
+ (lambda (_ignore-auto _noconfirm)
+ (diff-no-select old new switches no-async (current-buffer))))
+ (setq default-directory thisdir)
+ (let ((inhibit-read-only t))
+ (insert command "\n"))
+ (if (and (not no-async) (fboundp 'start-process))
+ (let ((proc (start-process "Diff" buf shell-file-name
+ shell-command-switch command)))
+ (set-process-filter proc 'diff-process-filter)
+ (set-process-sentinel
+ proc (lambda (proc _msg)
+ (with-current-buffer (process-buffer proc)
+ (diff-sentinel (process-exit-status proc))
+ (if old-alt (delete-file old-alt))
+ (if new-alt (delete-file new-alt))))))
+ ;; Async processes aren't available.
+ (let ((inhibit-read-only t))
+ (diff-sentinel
+ (call-process shell-file-name nil buf nil
+ shell-command-switch command))
+ (if old-alt (delete-file old-alt))
+ (if new-alt (delete-file new-alt)))))
+ buf)))
+
+(unless (fboundp 'diff-file-local-copy)
+ (defun diff-file-local-copy (file-or-buf)
+ (if (bufferp file-or-buf)
+ (with-current-buffer file-or-buf
+ (let ((tempfile (make-temp-file "buffer-content-")))
+ (write-region nil nil tempfile nil 'nomessage)
+ tempfile))
+ (file-local-copy file-or-buf))))
+
+
+;; `user-error' isn't defined in Emacs < 24.3
+(unless (fboundp 'user-error)
+ (defalias 'user-error 'error)
+ ;; prevent debugger being called on user errors
+ (add-to-list 'debug-ignored-errors "^No further undo information")
+ (add-to-list 'debug-ignored-errors "^No further redo information")
+ (add-to-list 'debug-ignored-errors "^No further redo information for region"))
+
+
+
+
+\f
+;;; =====================================================================
+;;; Global variables and customization options
+
+(defvar buffer-undo-tree nil
+ "Tree of undo entries in current buffer.")
+(put 'buffer-undo-tree 'permanent-local t)
+(make-variable-buffer-local 'buffer-undo-tree)
+
+
+(defgroup undo-tree nil
+ "Tree undo/redo."
+ :group 'undo)
+
+(defcustom undo-tree-mode-lighter " Undo-Tree"
+ "Lighter displayed in mode line
+when `undo-tree-mode' is enabled."
+ :group 'undo-tree
+ :type 'string)
+
+
+(defcustom undo-tree-incompatible-major-modes '(term-mode)
+ "List of major-modes in which `undo-tree-mode' should not be enabled.
+\(See `turn-on-undo-tree-mode'.\)"
+ :group 'undo-tree
+ :type '(repeat symbol))
+
+
+(defcustom undo-tree-enable-undo-in-region t
+ "When non-nil, enable undo-in-region.
+
+When undo-in-region is enabled, undoing or redoing when the
+region is active (in `transient-mark-mode') or with a prefix
+argument (not in `transient-mark-mode') only undoes changes
+within the current region."
+ :group 'undo-tree
+ :type 'boolean)
+
+
+(defcustom undo-tree-auto-save-history nil
+ "When non-nil, `undo-tree-mode' will save undo history to file
+when a buffer is saved to file.
+
+It will automatically load undo history when a buffer is loaded
+from file, if an undo save file exists.
+
+By default, undo-tree history is saved to a file called
+\".<buffer-file-name>.~undo-tree~\" in the same directory as the
+file itself. To save under a different directory, customize
+`undo-tree-history-directory-alist' (see the documentation for
+that variable for details).
+
+WARNING! `undo-tree-auto-save-history' will not work properly in
+Emacs versions prior to 24.3, so it cannot be enabled via
+the customization interface in versions earlier than that one. To
+ignore this warning and enable it regardless, set
+`undo-tree-auto-save-history' to a non-nil value outside of
+customize."
+ :group 'undo-tree
+ :type (if (version-list-< (version-to-list emacs-version) '(24 3))
+ '(choice (const :tag "<disabled>" nil))
+ 'boolean))
+
+
+(defcustom undo-tree-history-directory-alist nil
+ "Alist of filename patterns and undo history directory names.
+Each element looks like (REGEXP . DIRECTORY). Undo history for
+files with names matching REGEXP will be saved in DIRECTORY.
+DIRECTORY may be relative or absolute. If it is absolute, so
+that all matching files are backed up into the same directory,
+the file names in this directory will be the full name of the
+file backed up with all directory separators changed to `!' to
+prevent clashes. This will not work correctly if your filesystem
+truncates the resulting name.
+
+For the common case of all backups going into one directory, the
+alist should contain a single element pairing \".\" with the
+appropriate directory name.
+
+If this variable is nil, or it fails to match a filename, the
+backup is made in the original file's directory.
+
+On MS-DOS filesystems without long names this variable is always
+ignored."
+ :group 'undo-tree
+ :type '(repeat (cons (regexp :tag "Regexp matching filename")
+ (directory :tag "Undo history directory name"))))
+
+
+
+(defcustom undo-tree-visualizer-relative-timestamps t
+ "When non-nil, display times relative to current time
+when displaying time stamps in visualizer.
+
+Otherwise, display absolute times."
+ :group 'undo-tree
+ :type 'boolean)
+
+
+(defcustom undo-tree-visualizer-timestamps nil
+ "When non-nil, display time-stamps by default
+in undo-tree visualizer.
+
+\\<undo-tree-visualizer-mode-map>You can always toggle time-stamps on and off \
+using \\[undo-tree-visualizer-toggle-timestamps], regardless of the
+setting of this variable."
+ :group 'undo-tree
+ :type 'boolean)
+
+
+(defcustom undo-tree-visualizer-diff nil
+ "When non-nil, display diff by default in undo-tree visualizer.
+
+\\<undo-tree-visualizer-mode-map>You can always toggle the diff display \
+using \\[undo-tree-visualizer-toggle-diff], regardless of the
+setting of this variable."
+ :group 'undo-tree
+ :type 'boolean)
+
+
+(defcustom undo-tree-visualizer-lazy-drawing 100
+ "When non-nil, use lazy undo-tree drawing in visualizer.
+
+Setting this to a number causes the visualizer to switch to lazy
+drawing when the number of nodes in the tree is larger than this
+value.
+
+Lazy drawing means that only the visible portion of the tree will
+be drawn initially, and the tree will be extended later as
+needed. For the most part, the only visible effect of this is to
+significantly speed up displaying the visualizer for very large
+trees.
+
+There is one potential negative effect of lazy drawing. Other
+branches of the tree will only be drawn once the node from which
+they branch off becomes visible. So it can happen that certain
+portions of the tree that would be shown with lazy drawing
+disabled, will not be drawn immediately when it is
+enabled. However, this effect is quite rare in practice."
+ :group 'undo-tree
+ :type '(choice (const :tag "never" nil)
+ (const :tag "always" t)
+ (integer :tag "> size")))
+
+
+(defface undo-tree-visualizer-default-face
+ '((((class color)) :foreground "gray"))
+ "Face used to draw undo-tree in visualizer."
+ :group 'undo-tree)
+
+(defface undo-tree-visualizer-current-face
+ '((((class color)) :foreground "red"))
+ "Face used to highlight current undo-tree node in visualizer."
+ :group 'undo-tree)
+
+(defface undo-tree-visualizer-active-branch-face
+ '((((class color) (background dark))
+ (:foreground "white" :weight bold))
+ (((class color) (background light))
+ (:foreground "black" :weight bold)))
+ "Face used to highlight active undo-tree branch in visualizer."
+ :group 'undo-tree)
+
+(defface undo-tree-visualizer-register-face
+ '((((class color)) :foreground "yellow"))
+ "Face used to highlight undo-tree nodes saved to a register
+in visualizer."
+ :group 'undo-tree)
+
+(defface undo-tree-visualizer-unmodified-face
+ '((((class color)) :foreground "cyan"))
+ "Face used to highlight nodes corresponding to unmodified buffers
+in visualizer."
+ :group 'undo-tree)
+
+
+(defvar undo-tree-visualizer-parent-buffer nil
+ "Parent buffer in visualizer.")
+(put 'undo-tree-visualizer-parent-buffer 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-parent-buffer)
+
+;; stores modification time of parent buffer's file, if any
+(defvar undo-tree-visualizer-parent-mtime nil)
+(put 'undo-tree-visualizer-parent-mtime 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-parent-mtime)
+
+;; stores current horizontal spacing needed for drawing undo-tree
+(defvar undo-tree-visualizer-spacing nil)
+(put 'undo-tree-visualizer-spacing 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-spacing)
+
+;; calculate horizontal spacing required for drawing tree with current
+;; settings
+(defsubst undo-tree-visualizer-calculate-spacing ()
+ (if undo-tree-visualizer-timestamps
+ (if undo-tree-visualizer-relative-timestamps 9 13)
+ 3))
+
+;; holds node that was current when visualizer was invoked
+(defvar undo-tree-visualizer-initial-node nil)
+(put 'undo-tree-visualizer-initial-node 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-initial-node)
+
+;; holds currently selected node in visualizer selection mode
+(defvar undo-tree-visualizer-selected-node nil)
+(put 'undo-tree-visualizer-selected-node 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-selected)
+
+;; used to store nodes at edge of currently drawn portion of tree
+(defvar undo-tree-visualizer-needs-extending-down nil)
+(put 'undo-tree-visualizer-needs-extending-down 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-needs-extending-down)
+(defvar undo-tree-visualizer-needs-extending-up nil)
+(put 'undo-tree-visualizer-needs-extending-up 'permanent-local t)
+(make-variable-buffer-local 'undo-tree-visualizer-needs-extending-up)
+
+;; dynamically bound to t when undoing from visualizer, to inhibit
+;; `undo-tree-kill-visualizer' hook function in parent buffer
+(defvar undo-tree-inhibit-kill-visualizer nil)
+
+;; can be let-bound to a face name, used in drawing functions
+(defvar undo-tree-insert-face nil)
+
+;; visualizer buffer names
+(defconst undo-tree-visualizer-buffer-name " *undo-tree*")
+(defconst undo-tree-diff-buffer-name "*undo-tree Diff*")
+
+;; install history-auto-save hooks
+(add-hook 'write-file-functions 'undo-tree-save-history-hook)
+(add-hook 'find-file-hook 'undo-tree-load-history-hook)
+
+
+
+\f
+;;; =================================================================
+;;; Default keymaps
+
+(defvar undo-tree-map nil
+ "Keymap used in undo-tree-mode.")
+
+(unless undo-tree-map
+ (let ((map (make-sparse-keymap)))
+ ;; remap `undo' and `undo-only' to `undo-tree-undo'
+ (define-key map [remap undo] 'undo-tree-undo)
+ (define-key map [remap undo-only] 'undo-tree-undo)
+ ;; bind standard undo bindings (since these match redo counterparts)
+ (define-key map (kbd "C-/") 'undo-tree-undo)
+ (define-key map "\C-_" 'undo-tree-undo)
+ ;; redo doesn't exist normally, so define our own keybindings
+ (define-key map (kbd "C-?") 'undo-tree-redo)
+ (define-key map (kbd "M-_") 'undo-tree-redo)
+ ;; just in case something has defined `redo'...
+ (define-key map [remap redo] 'undo-tree-redo)
+ ;; we use "C-x u" for the undo-tree visualizer
+ (define-key map (kbd "\C-x u") 'undo-tree-visualize)
+ ;; bind register commands
+ (define-key map (kbd "C-x r u") 'undo-tree-save-state-to-register)
+ (define-key map (kbd "C-x r U") 'undo-tree-restore-state-from-register)
+ ;; set keymap
+ (setq undo-tree-map map)))
+
+
+(defvar undo-tree-visualizer-mode-map nil
+ "Keymap used in undo-tree visualizer.")
+
+(unless undo-tree-visualizer-mode-map
+ (let ((map (make-sparse-keymap)))
+ ;; vertical motion keys undo/redo
+ (define-key map [remap previous-line] 'undo-tree-visualize-undo)
+ (define-key map [remap next-line] 'undo-tree-visualize-redo)
+ (define-key map [up] 'undo-tree-visualize-undo)
+ (define-key map "p" 'undo-tree-visualize-undo)
+ (define-key map "\C-p" 'undo-tree-visualize-undo)
+ (define-key map [down] 'undo-tree-visualize-redo)
+ (define-key map "n" 'undo-tree-visualize-redo)
+ (define-key map "\C-n" 'undo-tree-visualize-redo)
+ ;; horizontal motion keys switch branch
+ (define-key map [remap forward-char]
+ 'undo-tree-visualize-switch-branch-right)
+ (define-key map [remap backward-char]
+ 'undo-tree-visualize-switch-branch-left)
+ (define-key map [right] 'undo-tree-visualize-switch-branch-right)
+ (define-key map "f" 'undo-tree-visualize-switch-branch-right)
+ (define-key map "\C-f" 'undo-tree-visualize-switch-branch-right)
+ (define-key map [left] 'undo-tree-visualize-switch-branch-left)
+ (define-key map "b" 'undo-tree-visualize-switch-branch-left)
+ (define-key map "\C-b" 'undo-tree-visualize-switch-branch-left)
+ ;; paragraph motion keys undo/redo to significant points in tree
+ (define-key map [remap backward-paragraph] 'undo-tree-visualize-undo-to-x)
+ (define-key map [remap forward-paragraph] 'undo-tree-visualize-redo-to-x)
+ (define-key map "\M-{" 'undo-tree-visualize-undo-to-x)
+ (define-key map "\M-}" 'undo-tree-visualize-redo-to-x)
+ (define-key map [C-up] 'undo-tree-visualize-undo-to-x)
+ (define-key map [C-down] 'undo-tree-visualize-redo-to-x)
+ ;; mouse sets buffer state to node at click
+ (define-key map [mouse-1] 'undo-tree-visualizer-mouse-set)
+ ;; toggle timestamps
+ (define-key map "t" 'undo-tree-visualizer-toggle-timestamps)
+ ;; toggle diff
+ (define-key map "d" 'undo-tree-visualizer-toggle-diff)
+ ;; toggle selection mode
+ (define-key map "s" 'undo-tree-visualizer-selection-mode)
+ ;; horizontal scrolling may be needed if the tree is very wide
+ (define-key map "," 'undo-tree-visualizer-scroll-left)
+ (define-key map "." 'undo-tree-visualizer-scroll-right)
+ (define-key map "<" 'undo-tree-visualizer-scroll-left)
+ (define-key map ">" 'undo-tree-visualizer-scroll-right)
+ ;; vertical scrolling may be needed if the tree is very tall
+ (define-key map [next] 'undo-tree-visualizer-scroll-up)
+ (define-key map [prior] 'undo-tree-visualizer-scroll-down)
+ ;; quit/abort visualizer
+ (define-key map "q" 'undo-tree-visualizer-quit)
+ (define-key map "\C-q" 'undo-tree-visualizer-abort)
+ ;; set keymap
+ (setq undo-tree-visualizer-mode-map map)))
+
+
+(defvar undo-tree-visualizer-selection-mode-map nil
+ "Keymap used in undo-tree visualizer selection mode.")
+
+(unless undo-tree-visualizer-selection-mode-map
+ (let ((map (make-sparse-keymap)))
+ ;; vertical motion keys move up and down tree
+ (define-key map [remap previous-line]
+ 'undo-tree-visualizer-select-previous)
+ (define-key map [remap next-line]
+ 'undo-tree-visualizer-select-next)
+ (define-key map [up] 'undo-tree-visualizer-select-previous)
+ (define-key map "p" 'undo-tree-visualizer-select-previous)
+ (define-key map "\C-p" 'undo-tree-visualizer-select-previous)
+ (define-key map [down] 'undo-tree-visualizer-select-next)
+ (define-key map "n" 'undo-tree-visualizer-select-next)
+ (define-key map "\C-n" 'undo-tree-visualizer-select-next)
+ ;; vertical scroll keys move up and down quickly
+ (define-key map [next]
+ (lambda () (interactive) (undo-tree-visualizer-select-next 10)))
+ (define-key map [prior]
+ (lambda () (interactive) (undo-tree-visualizer-select-previous 10)))
+ ;; horizontal motion keys move to left and right siblings
+ (define-key map [remap forward-char] 'undo-tree-visualizer-select-right)
+ (define-key map [remap backward-char] 'undo-tree-visualizer-select-left)
+ (define-key map [right] 'undo-tree-visualizer-select-right)
+ (define-key map "f" 'undo-tree-visualizer-select-right)
+ (define-key map "\C-f" 'undo-tree-visualizer-select-right)
+ (define-key map [left] 'undo-tree-visualizer-select-left)
+ (define-key map "b" 'undo-tree-visualizer-select-left)
+ (define-key map "\C-b" 'undo-tree-visualizer-select-left)
+ ;; horizontal scroll keys move left or right quickly
+ (define-key map ","
+ (lambda () (interactive) (undo-tree-visualizer-select-left 10)))
+ (define-key map "."
+ (lambda () (interactive) (undo-tree-visualizer-select-right 10)))
+ (define-key map "<"
+ (lambda () (interactive) (undo-tree-visualizer-select-left 10)))
+ (define-key map ">"
+ (lambda () (interactive) (undo-tree-visualizer-select-right 10)))
+ ;; <enter> sets buffer state to node at point
+ (define-key map "\r" 'undo-tree-visualizer-set)
+ ;; mouse selects node at click
+ (define-key map [mouse-1] 'undo-tree-visualizer-mouse-select)
+ ;; toggle diff
+ (define-key map "d" 'undo-tree-visualizer-selection-toggle-diff)
+ ;; set keymap
+ (setq undo-tree-visualizer-selection-mode-map map)))
+
+
+(defvar undo-tree-old-undo-menu-item nil)
+
+(defun undo-tree-update-menu-bar ()
+ "Update `undo-tree-mode' Edit menu items."
+ (if undo-tree-mode
+ (progn
+ ;; save old undo menu item, and install undo/redo menu items
+ (setq undo-tree-old-undo-menu-item
+ (cdr (assq 'undo (lookup-key global-map [menu-bar edit]))))
+ (define-key (lookup-key global-map [menu-bar edit])
+ [undo] '(menu-item "Undo" undo-tree-undo
+ :enable (and undo-tree-mode
+ (not buffer-read-only)
+ (not (eq t buffer-undo-list))
+ (not (eq nil buffer-undo-tree))
+ (undo-tree-node-previous
+ (undo-tree-current buffer-undo-tree)))
+ :help "Undo last operation"))
+ (define-key-after (lookup-key global-map [menu-bar edit])
+ [redo] '(menu-item "Redo" undo-tree-redo
+ :enable (and undo-tree-mode
+ (not buffer-read-only)
+ (not (eq t buffer-undo-list))
+ (not (eq nil buffer-undo-tree))
+ (undo-tree-node-next
+ (undo-tree-current buffer-undo-tree)))
+ :help "Redo last operation")
+ 'undo))
+ ;; uninstall undo/redo menu items
+ (define-key (lookup-key global-map [menu-bar edit])
+ [undo] undo-tree-old-undo-menu-item)
+ (define-key (lookup-key global-map [menu-bar edit])
+ [redo] nil)))
+
+(add-hook 'menu-bar-update-hook 'undo-tree-update-menu-bar)
+
+
+
+
+\f
+;;; =====================================================================
+;;; Undo-tree data structure
+
+(defstruct
+ (undo-tree
+ :named
+ (:constructor nil)
+ (:constructor make-undo-tree
+ (&aux
+ (root (undo-tree-make-node nil nil))
+ (current root)
+ (size 0)
+ (count 0)
+ (object-pool (make-hash-table :test 'eq :weakness 'value))))
+ ;;(:copier nil)
+ )
+ root current size count object-pool)
+
+
+
+(defstruct
+ (undo-tree-node
+ (:type vector) ; create unnamed struct
+ (:constructor nil)
+ (:constructor undo-tree-make-node
+ (previous undo
+ &optional redo
+ &aux
+ (timestamp (current-time))
+ (branch 0)))
+ (:constructor undo-tree-make-node-backwards
+ (next-node undo
+ &optional redo
+ &aux
+ (next (list next-node))
+ (timestamp (current-time))
+ (branch 0)))
+ (:copier nil))
+ previous next undo redo timestamp branch meta-data)
+
+
+(defmacro undo-tree-node-p (n)
+ (let ((len (length (undo-tree-make-node nil nil))))
+ `(and (vectorp ,n) (= (length ,n) ,len))))
+
+
+
+(defstruct
+ (undo-tree-region-data
+ (:type vector) ; create unnamed struct
+ (:constructor nil)
+ (:constructor undo-tree-make-region-data
+ (&optional undo-beginning undo-end
+ redo-beginning redo-end))
+ (:constructor undo-tree-make-undo-region-data
+ (undo-beginning undo-end))
+ (:constructor undo-tree-make-redo-region-data
+ (redo-beginning redo-end))
+ (:copier nil))
+ undo-beginning undo-end redo-beginning redo-end)
+
+
+(defmacro undo-tree-region-data-p (r)
+ (let ((len (length (undo-tree-make-region-data))))
+ `(and (vectorp ,r) (= (length ,r) ,len))))
+
+(defmacro undo-tree-node-clear-region-data (node)
+ `(setf (undo-tree-node-meta-data ,node)
+ (delq nil
+ (delq :region
+ (plist-put (undo-tree-node-meta-data ,node)
+ :region nil)))))
+
+
+(defmacro undo-tree-node-undo-beginning (node)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (when (undo-tree-region-data-p r)
+ (undo-tree-region-data-undo-beginning r))))
+
+(defmacro undo-tree-node-undo-end (node)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (when (undo-tree-region-data-p r)
+ (undo-tree-region-data-undo-end r))))
+
+(defmacro undo-tree-node-redo-beginning (node)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (when (undo-tree-region-data-p r)
+ (undo-tree-region-data-redo-beginning r))))
+
+(defmacro undo-tree-node-redo-end (node)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (when (undo-tree-region-data-p r)
+ (undo-tree-region-data-redo-end r))))
+
+
+(defsetf undo-tree-node-undo-beginning (node) (val)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (unless (undo-tree-region-data-p r)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :region
+ (setq r (undo-tree-make-region-data)))))
+ (setf (undo-tree-region-data-undo-beginning r) ,val)))
+
+(defsetf undo-tree-node-undo-end (node) (val)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (unless (undo-tree-region-data-p r)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :region
+ (setq r (undo-tree-make-region-data)))))
+ (setf (undo-tree-region-data-undo-end r) ,val)))
+
+(defsetf undo-tree-node-redo-beginning (node) (val)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (unless (undo-tree-region-data-p r)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :region
+ (setq r (undo-tree-make-region-data)))))
+ (setf (undo-tree-region-data-redo-beginning r) ,val)))
+
+(defsetf undo-tree-node-redo-end (node) (val)
+ `(let ((r (plist-get (undo-tree-node-meta-data ,node) :region)))
+ (unless (undo-tree-region-data-p r)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :region
+ (setq r (undo-tree-make-region-data)))))
+ (setf (undo-tree-region-data-redo-end r) ,val)))
+
+
+
+(defstruct
+ (undo-tree-visualizer-data
+ (:type vector) ; create unnamed struct
+ (:constructor nil)
+ (:constructor undo-tree-make-visualizer-data
+ (&optional lwidth cwidth rwidth marker))
+ (:copier nil))
+ lwidth cwidth rwidth marker)
+
+
+(defmacro undo-tree-visualizer-data-p (v)
+ (let ((len (length (undo-tree-make-visualizer-data))))
+ `(and (vectorp ,v) (= (length ,v) ,len))))
+
+(defun undo-tree-node-clear-visualizer-data (node)
+ (let ((plist (undo-tree-node-meta-data node)))
+ (if (eq (car plist) :visualizer)
+ (setf (undo-tree-node-meta-data node) (nthcdr 2 plist))
+ (while (and plist (not (eq (cadr plist) :visualizer)))
+ (setq plist (cdr plist)))
+ (if plist (setcdr plist (nthcdr 3 plist))))))
+
+(defmacro undo-tree-node-lwidth (node)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (when (undo-tree-visualizer-data-p v)
+ (undo-tree-visualizer-data-lwidth v))))
+
+(defmacro undo-tree-node-cwidth (node)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (when (undo-tree-visualizer-data-p v)
+ (undo-tree-visualizer-data-cwidth v))))
+
+(defmacro undo-tree-node-rwidth (node)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (when (undo-tree-visualizer-data-p v)
+ (undo-tree-visualizer-data-rwidth v))))
+
+(defmacro undo-tree-node-marker (node)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (when (undo-tree-visualizer-data-p v)
+ (undo-tree-visualizer-data-marker v))))
+
+
+(defsetf undo-tree-node-lwidth (node) (val)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (unless (undo-tree-visualizer-data-p v)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :visualizer
+ (setq v (undo-tree-make-visualizer-data)))))
+ (setf (undo-tree-visualizer-data-lwidth v) ,val)))
+
+(defsetf undo-tree-node-cwidth (node) (val)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (unless (undo-tree-visualizer-data-p v)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :visualizer
+ (setq v (undo-tree-make-visualizer-data)))))
+ (setf (undo-tree-visualizer-data-cwidth v) ,val)))
+
+(defsetf undo-tree-node-rwidth (node) (val)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (unless (undo-tree-visualizer-data-p v)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :visualizer
+ (setq v (undo-tree-make-visualizer-data)))))
+ (setf (undo-tree-visualizer-data-rwidth v) ,val)))
+
+(defsetf undo-tree-node-marker (node) (val)
+ `(let ((v (plist-get (undo-tree-node-meta-data ,node) :visualizer)))
+ (unless (undo-tree-visualizer-data-p v)
+ (setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :visualizer
+ (setq v (undo-tree-make-visualizer-data)))))
+ (setf (undo-tree-visualizer-data-marker v) ,val)))
+
+
+
+(defstruct
+ (undo-tree-register-data
+ (:type vector)
+ (:constructor nil)
+ (:constructor undo-tree-make-register-data (buffer node)))
+ buffer node)
+
+(defun undo-tree-register-data-p (data)
+ (and (vectorp data)
+ (= (length data) 2)
+ (undo-tree-node-p (undo-tree-register-data-node data))))
+
+(defun undo-tree-register-data-print-func (data)
+ (princ (format "an undo-tree state for buffer %s"
+ (undo-tree-register-data-buffer data))))
+
+(defmacro undo-tree-node-register (node)
+ `(plist-get (undo-tree-node-meta-data ,node) :register))
+
+(defsetf undo-tree-node-register (node) (val)
+ `(setf (undo-tree-node-meta-data ,node)
+ (plist-put (undo-tree-node-meta-data ,node) :register ,val)))
+
+
+
+\f
+;;; =====================================================================
+;;; Basic undo-tree data structure functions
+
+(defun undo-tree-grow (undo)
+ "Add an UNDO node to current branch of `buffer-undo-tree'."
+ (let* ((current (undo-tree-current buffer-undo-tree))
+ (new (undo-tree-make-node current undo)))
+ (push new (undo-tree-node-next current))
+ (setf (undo-tree-current buffer-undo-tree) new)))
+
+
+(defun undo-tree-grow-backwards (node undo &optional redo)
+ "Add new node *above* undo-tree NODE, and return new node.
+Note that this will overwrite NODE's \"previous\" link, so should
+only be used on a detached NODE, never on nodes that are already
+part of `buffer-undo-tree'."
+ (let ((new (undo-tree-make-node-backwards node undo redo)))
+ (setf (undo-tree-node-previous node) new)
+ new))
+
+
+(defun undo-tree-splice-node (node splice)
+ "Splice NODE into undo tree, below node SPLICE.
+Note that this will overwrite NODE's \"next\" and \"previous\"
+links, so should only be used on a detached NODE, never on nodes
+that are already part of `buffer-undo-tree'."
+ (setf (undo-tree-node-next node) (undo-tree-node-next splice)
+ (undo-tree-node-branch node) (undo-tree-node-branch splice)
+ (undo-tree-node-previous node) splice
+ (undo-tree-node-next splice) (list node)
+ (undo-tree-node-branch splice) 0)
+ (dolist (n (undo-tree-node-next node))
+ (setf (undo-tree-node-previous n) node)))
+
+
+(defun undo-tree-snip-node (node)
+ "Snip NODE out of undo tree."
+ (let* ((parent (undo-tree-node-previous node))
+ position p)
+ ;; if NODE is only child, replace parent's next links with NODE's
+ (if (= (length (undo-tree-node-next parent)) 0)
+ (setf (undo-tree-node-next parent) (undo-tree-node-next node)
+ (undo-tree-node-branch parent) (undo-tree-node-branch node))
+ ;; otherwise...
+ (setq position (undo-tree-position node (undo-tree-node-next parent)))
+ (cond
+ ;; if active branch used do go via NODE, set parent's branch to active
+ ;; branch of NODE
+ ((= (undo-tree-node-branch parent) position)
+ (setf (undo-tree-node-branch parent)
+ (+ position (undo-tree-node-branch node))))
+ ;; if active branch didn't go via NODE, update parent's branch to point
+ ;; to same node as before
+ ((> (undo-tree-node-branch parent) position)
+ (incf (undo-tree-node-branch parent)
+ (1- (length (undo-tree-node-next node))))))
+ ;; replace NODE in parent's next list with NODE's entire next list
+ (if (= position 0)
+ (setf (undo-tree-node-next parent)
+ (nconc (undo-tree-node-next node)
+ (cdr (undo-tree-node-next parent))))
+ (setq p (nthcdr (1- position) (undo-tree-node-next parent)))
+ (setcdr p (nconc (undo-tree-node-next node) (cddr p)))))
+ ;; update previous links of NODE's children
+ (dolist (n (undo-tree-node-next node))
+ (setf (undo-tree-node-previous n) parent))))
+
+
+(defun undo-tree-mapc (--undo-tree-mapc-function-- node)
+ ;; Apply FUNCTION to NODE and to each node below it.
+ (let ((stack (list node))
+ n)
+ (while stack
+ (setq n (pop stack))
+ (funcall --undo-tree-mapc-function-- n)
+ (setq stack (append (undo-tree-node-next n) stack)))))
+
+
+(defmacro undo-tree-num-branches ()
+ "Return number of branches at current undo tree node."
+ '(length (undo-tree-node-next (undo-tree-current buffer-undo-tree))))
+
+
+(defun undo-tree-position (node list)
+ "Find the first occurrence of NODE in LIST.
+Return the index of the matching item, or nil of not found.
+Comparison is done with `eq'."
+ (let ((i 0))
+ (catch 'found
+ (while (progn
+ (when (eq node (car list)) (throw 'found i))
+ (incf i)
+ (setq list (cdr list))))
+ nil)))
+
+
+(defvar *undo-tree-id-counter* 0)
+(make-variable-buffer-local '*undo-tree-id-counter*)
+
+(defmacro undo-tree-generate-id ()
+ ;; Generate a new, unique id (uninterned symbol).
+ ;; The name is made by appending a number to "undo-tree-id".
+ ;; (Copied from CL package `gensym'.)
+ `(let ((num (prog1 *undo-tree-id-counter* (incf *undo-tree-id-counter*))))
+ (make-symbol (format "undo-tree-id%d" num))))
+
+
+(defun undo-tree-decircle (undo-tree)
+ ;; Nullify PREVIOUS links of UNDO-TREE nodes, to make UNDO-TREE data
+ ;; structure non-circular.
+ (undo-tree-mapc
+ (lambda (node)
+ (dolist (n (undo-tree-node-next node))
+ (setf (undo-tree-node-previous n) nil)))
+ (undo-tree-root undo-tree)))
+
+
+(defun undo-tree-recircle (undo-tree)
+ ;; Recreate PREVIOUS links of UNDO-TREE nodes, to restore circular UNDO-TREE
+ ;; data structure.
+ (undo-tree-mapc
+ (lambda (node)
+ (dolist (n (undo-tree-node-next node))
+ (setf (undo-tree-node-previous n) node)))
+ (undo-tree-root undo-tree)))
+
+
+
+\f
+;;; =====================================================================
+;;; Undo list and undo changeset utility functions
+
+(defmacro undo-list-marker-elt-p (elt)
+ `(markerp (car-safe ,elt)))
+
+(defmacro undo-list-GCd-marker-elt-p (elt)
+ ;; Return t if ELT is a marker element whose marker has been moved to the
+ ;; object-pool, so may potentially have been garbage-collected.
+ ;; Note: Valid marker undo elements should be uniquely identified as cons
+ ;; cells with a symbol in the car (replacing the marker), and a number in
+ ;; the cdr. However, to guard against future changes to undo element
+ ;; formats, we perform an additional redundant check on the symbol name.
+ `(and (car-safe ,elt)
+ (symbolp (car ,elt))
+ (let ((str (symbol-name (car ,elt))))
+ (and (> (length str) 12)
+ (string= (substring str 0 12) "undo-tree-id")))
+ (numberp (cdr-safe ,elt))))
+
+
+(defun undo-tree-move-GC-elts-to-pool (elt)
+ ;; Move elements that can be garbage-collected into `buffer-undo-tree'
+ ;; object pool, substituting a unique id that can be used to retrieve them
+ ;; later. (Only markers require this treatment currently.)
+ (when (undo-list-marker-elt-p elt)
+ (let ((id (undo-tree-generate-id)))
+ (puthash id (car elt) (undo-tree-object-pool buffer-undo-tree))
+ (setcar elt id))))
+
+
+(defun undo-tree-restore-GC-elts-from-pool (elt)
+ ;; Replace object id's in ELT with corresponding objects from
+ ;; `buffer-undo-tree' object pool and return modified ELT, or return nil if
+ ;; any object in ELT has been garbage-collected.
+ (if (undo-list-GCd-marker-elt-p elt)
+ (when (setcar elt (gethash (car elt)
+ (undo-tree-object-pool buffer-undo-tree)))
+ elt)
+ elt))
+
+
+(defun undo-list-clean-GCd-elts (undo-list)
+ ;; Remove object id's from UNDO-LIST that refer to elements that have been
+ ;; garbage-collected. UNDO-LIST is modified by side-effect.
+ (while (undo-list-GCd-marker-elt-p (car undo-list))
+ (unless (gethash (caar undo-list)
+ (undo-tree-object-pool buffer-undo-tree))
+ (setq undo-list (cdr undo-list))))
+ (let ((p undo-list))
+ (while (cdr p)
+ (when (and (undo-list-GCd-marker-elt-p (cadr p))
+ (null (gethash (car (cadr p))
+ (undo-tree-object-pool buffer-undo-tree))))
+ (setcdr p (cddr p)))
+ (setq p (cdr p))))
+ undo-list)
+
+
+(defun undo-list-pop-changeset (&optional discard-pos)
+ ;; Pop changeset from `buffer-undo-list'. If DISCARD-POS is non-nil, discard
+ ;; any position entries from changeset.
+
+ ;; discard undo boundaries and (if DISCARD-POS is non-nil) position entries
+ ;; at head of undo list
+ (while (or (null (car buffer-undo-list))
+ (and discard-pos (integerp (car buffer-undo-list))))
+ (setq buffer-undo-list (cdr buffer-undo-list)))
+ ;; pop elements up to next undo boundary, discarding position entries if
+ ;; DISCARD-POS is non-nil
+ (if (eq (car buffer-undo-list) 'undo-tree-canary)
+ (push nil buffer-undo-list)
+ (let* ((changeset (list (pop buffer-undo-list)))
+ (p changeset))
+ (while (progn
+ (undo-tree-move-GC-elts-to-pool (car p))
+ (while (and discard-pos (integerp (car buffer-undo-list)))
+ (setq buffer-undo-list (cdr buffer-undo-list)))
+ (and (car buffer-undo-list)
+ (not (eq (car buffer-undo-list) 'undo-tree-canary))))
+ (setcdr p (list (pop buffer-undo-list)))
+ (setq p (cdr p)))
+ changeset)))
+
+
+(defun undo-tree-copy-list (undo-list)
+ ;; Return a deep copy of first changeset in `undo-list'. Object id's are
+ ;; replaced by corresponding objects from `buffer-undo-tree' object-pool.
+ (let (copy p)
+ ;; if first element contains an object id, replace it with object from
+ ;; pool, discarding element entirely if it's been GC'd
+ (while (and undo-list (null copy))
+ (setq copy
+ (undo-tree-restore-GC-elts-from-pool (pop undo-list))))
+ (when copy
+ (setq copy (list copy)
+ p copy)
+ ;; copy remaining elements, replacing object id's with objects from
+ ;; pool, or discarding them entirely if they've been GC'd
+ (while undo-list
+ (when (setcdr p (undo-tree-restore-GC-elts-from-pool
+ (undo-copy-list-1 (pop undo-list))))
+ (setcdr p (list (cdr p)))
+ (setq p (cdr p))))
+ copy)))
+
+
+
+(defun undo-list-transfer-to-tree ()
+ ;; Transfer entries accumulated in `buffer-undo-list' to `buffer-undo-tree'.
+
+ ;; `undo-list-transfer-to-tree' should never be called when undo is disabled
+ ;; (i.e. `buffer-undo-tree' is t)
+ (assert (not (eq buffer-undo-tree t)))
+
+ ;; if `buffer-undo-tree' is empty, create initial undo-tree
+ (when (null buffer-undo-tree) (setq buffer-undo-tree (make-undo-tree)))
+ ;; make sure there's a canary at end of `buffer-undo-list'
+ (when (null buffer-undo-list)
+ (setq buffer-undo-list '(nil undo-tree-canary)))
+
+ (unless (or (eq (cadr buffer-undo-list) 'undo-tree-canary)
+ (eq (car buffer-undo-list) 'undo-tree-canary))
+ ;; create new node from first changeset in `buffer-undo-list', save old
+ ;; `buffer-undo-tree' current node, and make new node the current node
+ (let* ((node (undo-tree-make-node nil (undo-list-pop-changeset)))
+ (splice (undo-tree-current buffer-undo-tree))
+ (size (undo-list-byte-size (undo-tree-node-undo node)))
+ (count 1))
+ (setf (undo-tree-current buffer-undo-tree) node)
+ ;; grow tree fragment backwards using `buffer-undo-list' changesets
+ (while (and buffer-undo-list
+ (not (eq (cadr buffer-undo-list) 'undo-tree-canary)))
+ (setq node
+ (undo-tree-grow-backwards node (undo-list-pop-changeset)))
+ (incf size (undo-list-byte-size (undo-tree-node-undo node)))
+ (incf count))
+ ;; if no undo history has been discarded from `buffer-undo-list' since
+ ;; last transfer, splice new tree fragment onto end of old
+ ;; `buffer-undo-tree' current node
+ (if (or (eq (cadr buffer-undo-list) 'undo-tree-canary)
+ (eq (car buffer-undo-list) 'undo-tree-canary))
+ (progn
+ (setf (undo-tree-node-previous node) splice)
+ (push node (undo-tree-node-next splice))
+ (setf (undo-tree-node-branch splice) 0)
+ (incf (undo-tree-size buffer-undo-tree) size)
+ (incf (undo-tree-count buffer-undo-tree) count))
+ ;; if undo history has been discarded, replace entire
+ ;; `buffer-undo-tree' with new tree fragment
+ (setq node (undo-tree-grow-backwards node nil))
+ (setf (undo-tree-root buffer-undo-tree) node)
+ (setq buffer-undo-list '(nil undo-tree-canary))
+ (setf (undo-tree-size buffer-undo-tree) size)
+ (setf (undo-tree-count buffer-undo-tree) count)
+ (setq buffer-undo-list '(nil undo-tree-canary))))
+ ;; discard undo history if necessary
+ (undo-tree-discard-history)))
+
+
+(defun undo-list-byte-size (undo-list)
+ ;; Return size (in bytes) of UNDO-LIST
+ (let ((size 0) (p undo-list))
+ (while p
+ (incf size 8) ; cons cells use up 8 bytes
+ (when (and (consp (car p)) (stringp (caar p)))
+ (incf size (string-bytes (caar p))))
+ (setq p (cdr p)))
+ size))
+
+
+
+(defun undo-list-rebuild-from-tree ()
+ "Rebuild `buffer-undo-list' from information in `buffer-undo-tree'."
+ (unless (eq buffer-undo-list t)
+ (undo-list-transfer-to-tree)
+ (setq buffer-undo-list nil)
+ (when buffer-undo-tree
+ (let ((stack (list (list (undo-tree-root buffer-undo-tree)))))
+ (push (sort (mapcar 'identity (undo-tree-node-next (caar stack)))
+ (lambda (a b)
+ (time-less-p (undo-tree-node-timestamp a)
+ (undo-tree-node-timestamp b))))
+ stack)
+ ;; Traverse tree in depth-and-oldest-first order, but add undo records
+ ;; on the way down, and redo records on the way up.
+ (while (or (car stack)
+ (not (eq (car (nth 1 stack))
+ (undo-tree-current buffer-undo-tree))))
+ (if (car stack)
+ (progn
+ (setq buffer-undo-list
+ (append (undo-tree-node-undo (caar stack))
+ buffer-undo-list))
+ (undo-boundary)
+ (push (sort (mapcar 'identity
+ (undo-tree-node-next (caar stack)))
+ (lambda (a b)
+ (time-less-p (undo-tree-node-timestamp a)
+ (undo-tree-node-timestamp b))))
+ stack))
+ (pop stack)
+ (setq buffer-undo-list
+ (append (undo-tree-node-redo (caar stack))
+ buffer-undo-list))
+ (undo-boundary)
+ (pop (car stack))))))))
+
+
+
+\f
+;;; =====================================================================
+;;; History discarding utility functions
+
+(defun undo-tree-oldest-leaf (node)
+ ;; Return oldest leaf node below NODE.
+ (while (undo-tree-node-next node)
+ (setq node
+ (car (sort (mapcar 'identity (undo-tree-node-next node))
+ (lambda (a b)
+ (time-less-p (undo-tree-node-timestamp a)
+ (undo-tree-node-timestamp b)))))))
+ node)
+
+
+(defun undo-tree-discard-node (node)
+ ;; Discard NODE from `buffer-undo-tree', and return next in line for
+ ;; discarding.
+
+ ;; don't discard current node
+ (unless (eq node (undo-tree-current buffer-undo-tree))
+
+ ;; discarding root node...
+ (if (eq node (undo-tree-root buffer-undo-tree))
+ (cond
+ ;; should always discard branches before root
+ ((> (length (undo-tree-node-next node)) 1)
+ (error "Trying to discard undo-tree root which still\
+ has multiple branches"))
+ ;; don't discard root if current node is only child
+ ((eq (car (undo-tree-node-next node))
+ (undo-tree-current buffer-undo-tree))
+ nil)
+ ;; discard root
+ (t
+ ;; clear any register referring to root
+ (let ((r (undo-tree-node-register node)))
+ (when (and r (eq (get-register r) node))
+ (set-register r nil)))
+ ;; make child of root into new root
+ (setq node (setf (undo-tree-root buffer-undo-tree)
+ (car (undo-tree-node-next node))))
+ ;; update undo-tree size
+ (decf (undo-tree-size buffer-undo-tree)
+ (+ (undo-list-byte-size (undo-tree-node-undo node))
+ (undo-list-byte-size (undo-tree-node-redo node))))
+ (decf (undo-tree-count buffer-undo-tree))
+ ;; discard new root's undo data and PREVIOUS link
+ (setf (undo-tree-node-undo node) nil
+ (undo-tree-node-redo node) nil
+ (undo-tree-node-previous node) nil)
+ ;; if new root has branches, or new root is current node, next node
+ ;; to discard is oldest leaf, otherwise it's new root
+ (if (or (> (length (undo-tree-node-next node)) 1)
+ (eq (car (undo-tree-node-next node))
+ (undo-tree-current buffer-undo-tree)))
+ (undo-tree-oldest-leaf node)
+ node)))
+
+ ;; discarding leaf node...
+ (let* ((parent (undo-tree-node-previous node))
+ (current (nth (undo-tree-node-branch parent)
+ (undo-tree-node-next parent))))
+ ;; clear any register referring to the discarded node
+ (let ((r (undo-tree-node-register node)))
+ (when (and r (eq (get-register r) node))
+ (set-register r nil)))
+ ;; update undo-tree size
+ (decf (undo-tree-size buffer-undo-tree)
+ (+ (undo-list-byte-size (undo-tree-node-undo node))
+ (undo-list-byte-size (undo-tree-node-redo node))))
+ (decf (undo-tree-count buffer-undo-tree))
+ ;; discard leaf
+ (setf (undo-tree-node-next parent)
+ (delq node (undo-tree-node-next parent))
+ (undo-tree-node-branch parent)
+ (undo-tree-position current (undo-tree-node-next parent)))
+ ;; if parent has branches, or parent is current node, next node to
+ ;; discard is oldest leaf, otherwise it's the parent itself
+ (if (or (eq parent (undo-tree-current buffer-undo-tree))
+ (and (undo-tree-node-next parent)
+ (or (not (eq parent (undo-tree-root buffer-undo-tree)))
+ (> (length (undo-tree-node-next parent)) 1))))
+ (undo-tree-oldest-leaf parent)
+ parent)))))
+
+
+
+(defun undo-tree-discard-history ()
+ "Discard undo history until we're within memory usage limits
+set by `undo-limit', `undo-strong-limit' and `undo-outer-limit'."
+
+ (when (> (undo-tree-size buffer-undo-tree) undo-limit)
+ ;; if there are no branches off root, first node to discard is root;
+ ;; otherwise it's leaf node at botom of oldest branch
+ (let ((node (if (> (length (undo-tree-node-next
+ (undo-tree-root buffer-undo-tree))) 1)
+ (undo-tree-oldest-leaf (undo-tree-root buffer-undo-tree))
+ (undo-tree-root buffer-undo-tree))))
+
+ ;; discard nodes until memory use is within `undo-strong-limit'
+ (while (and node
+ (> (undo-tree-size buffer-undo-tree) undo-strong-limit))
+ (setq node (undo-tree-discard-node node)))
+
+ ;; discard nodes until next node to discard would bring memory use
+ ;; within `undo-limit'
+ (while (and node
+ ;; check first if last discard has brought us within
+ ;; `undo-limit', in case we can avoid more expensive
+ ;; `undo-strong-limit' calculation
+ ;; Note: this assumes undo-strong-limit > undo-limit;
+ ;; if not, effectively undo-strong-limit = undo-limit
+ (> (undo-tree-size buffer-undo-tree) undo-limit)
+ (> (- (undo-tree-size buffer-undo-tree)
+ ;; if next node to discard is root, the memory we
+ ;; free-up comes from discarding changesets from its
+ ;; only child...
+ (if (eq node (undo-tree-root buffer-undo-tree))
+ (+ (undo-list-byte-size
+ (undo-tree-node-undo
+ (car (undo-tree-node-next node))))
+ (undo-list-byte-size
+ (undo-tree-node-redo
+ (car (undo-tree-node-next node)))))
+ ;; ...otherwise, it comes from discarding changesets
+ ;; from along with the node itself
+ (+ (undo-list-byte-size (undo-tree-node-undo node))
+ (undo-list-byte-size (undo-tree-node-redo node)))
+ ))
+ undo-limit))
+ (setq node (undo-tree-discard-node node)))
+
+ ;; if we're still over the `undo-outer-limit', discard entire history
+ (when (> (undo-tree-size buffer-undo-tree) undo-outer-limit)
+ ;; query first if `undo-ask-before-discard' is set
+ (if undo-ask-before-discard
+ (when (yes-or-no-p
+ (format
+ "Buffer `%s' undo info is %d bytes long; discard it? "
+ (buffer-name) (undo-tree-size buffer-undo-tree)))
+ (setq buffer-undo-tree nil))
+ ;; otherwise, discard and display warning
+ (display-warning
+ '(undo discard-info)
+ (concat
+ (format "Buffer `%s' undo info was %d bytes long.\n"
+ (buffer-name) (undo-tree-size buffer-undo-tree))
+ "The undo info was discarded because it exceeded\
+ `undo-outer-limit'.
+
+This is normal if you executed a command that made a huge change
+to the buffer. In that case, to prevent similar problems in the
+future, set `undo-outer-limit' to a value that is large enough to
+cover the maximum size of normal changes you expect a single
+command to make, but not so large that it might exceed the
+maximum memory allotted to Emacs.
+
+If you did not execute any such command, the situation is
+probably due to a bug and you should report it.
+
+You can disable the popping up of this buffer by adding the entry
+\(undo discard-info) to the user option `warning-suppress-types',
+which is defined in the `warnings' library.\n")
+ :warning)
+ (setq buffer-undo-tree nil)))
+ )))
+
+
+
+\f
+;;; =====================================================================
+;;; Visualizer utility functions
+
+(defun undo-tree-compute-widths (node)
+ "Recursively compute widths for nodes below NODE."
+ (let ((stack (list node))
+ res)
+ (while stack
+ ;; try to compute widths for node at top of stack
+ (if (undo-tree-node-p
+ (setq res (undo-tree-node-compute-widths (car stack))))
+ ;; if computation fails, it returns a node whose widths still need
+ ;; computing, which we push onto the stack
+ (push res stack)
+ ;; otherwise, store widths and remove it from stack
+ (setf (undo-tree-node-lwidth (car stack)) (aref res 0)
+ (undo-tree-node-cwidth (car stack)) (aref res 1)
+ (undo-tree-node-rwidth (car stack)) (aref res 2))
+ (pop stack)))))
+
+
+(defun undo-tree-node-compute-widths (node)
+ ;; Compute NODE's left-, centre-, and right-subtree widths. Returns widths
+ ;; (in a vector) if successful. Otherwise, returns a node whose widths need
+ ;; calculating before NODE's can be calculated.
+ (let ((num-children (length (undo-tree-node-next node)))
+ (lwidth 0) (cwidth 0) (rwidth 0) p)
+ (catch 'need-widths
+ (cond
+ ;; leaf nodes have 0 width
+ ((= 0 num-children)
+ (setf cwidth 1
+ (undo-tree-node-lwidth node) 0
+ (undo-tree-node-cwidth node) 1
+ (undo-tree-node-rwidth node) 0))
+
+ ;; odd number of children
+ ((= (mod num-children 2) 1)
+ (setq p (undo-tree-node-next node))
+ ;; compute left-width
+ (dotimes (i (/ num-children 2))
+ (if (undo-tree-node-lwidth (car p))
+ (incf lwidth (+ (undo-tree-node-lwidth (car p))
+ (undo-tree-node-cwidth (car p))
+ (undo-tree-node-rwidth (car p))))
+ ;; if child's widths haven't been computed, return that child
+ (throw 'need-widths (car p)))
+ (setq p (cdr p)))
+ (if (undo-tree-node-lwidth (car p))
+ (incf lwidth (undo-tree-node-lwidth (car p)))
+ (throw 'need-widths (car p)))
+ ;; centre-width is inherited from middle child
+ (setf cwidth (undo-tree-node-cwidth (car p)))
+ ;; compute right-width
+ (incf rwidth (undo-tree-node-rwidth (car p)))
+ (setq p (cdr p))
+ (dotimes (i (/ num-children 2))
+ (if (undo-tree-node-lwidth (car p))
+ (incf rwidth (+ (undo-tree-node-lwidth (car p))
+ (undo-tree-node-cwidth (car p))
+ (undo-tree-node-rwidth (car p))))
+ (throw 'need-widths (car p)))
+ (setq p (cdr p))))
+
+ ;; even number of children
+ (t
+ (setq p (undo-tree-node-next node))
+ ;; compute left-width
+ (dotimes (i (/ num-children 2))
+ (if (undo-tree-node-lwidth (car p))
+ (incf lwidth (+ (undo-tree-node-lwidth (car p))
+ (undo-tree-node-cwidth (car p))
+ (undo-tree-node-rwidth (car p))))
+ (throw 'need-widths (car p)))
+ (setq p (cdr p)))
+ ;; centre-width is 0 when number of children is even
+ (setq cwidth 0)
+ ;; compute right-width
+ (dotimes (i (/ num-children 2))
+ (if (undo-tree-node-lwidth (car p))
+ (incf rwidth (+ (undo-tree-node-lwidth (car p))
+ (undo-tree-node-cwidth (car p))
+ (undo-tree-node-rwidth (car p))))
+ (throw 'need-widths (car p)))
+ (setq p (cdr p)))))
+
+ ;; return left-, centre- and right-widths
+ (vector lwidth cwidth rwidth))))
+
+
+(defun undo-tree-clear-visualizer-data (tree)
+ ;; Clear visualizer data below NODE.
+ (undo-tree-mapc
+ (lambda (n) (undo-tree-node-clear-visualizer-data n))
+ (undo-tree-root tree)))
+
+
+(defun undo-tree-node-unmodified-p (node &optional mtime)
+ ;; Return non-nil if NODE corresponds to a buffer state that once upon a
+ ;; time was unmodified. If a file modification time MTIME is specified,
+ ;; return non-nil if the corresponding buffer state really is unmodified.
+ (let (changeset ntime)
+ (setq changeset
+ (or (undo-tree-node-redo node)
+ (and (setq changeset (car (undo-tree-node-next node)))
+ (undo-tree-node-undo changeset)))
+ ntime
+ (catch 'found
+ (dolist (elt changeset)
+ (when (and (consp elt) (eq (car elt) t) (consp (cdr elt))
+ (throw 'found (cdr elt)))))))
+ (and ntime
+ (or (null mtime)
+ ;; high-precision timestamps
+ (if (listp (cdr ntime))
+ (equal ntime mtime)
+ ;; old-style timestamps
+ (and (= (car ntime) (car mtime))
+ (= (cdr ntime) (cadr mtime))))))))
+
+
+
+\f
+;;; =====================================================================
+;;; Undo-in-region utility functions
+
+;; `undo-elt-in-region' uses this as a dynamically-scoped variable
+(defvar undo-adjusted-markers nil)
+
+
+(defun undo-tree-pull-undo-in-region-branch (start end)
+ ;; Pull out entries from undo changesets to create a new undo-in-region
+ ;; branch, which undoes changeset entries lying between START and END first,
+ ;; followed by remaining entries from the changesets, before rejoining the
+ ;; existing undo tree history. Repeated calls will, if appropriate, extend
+ ;; the current undo-in-region branch rather than creating a new one.
+
+ ;; if we're just reverting the last redo-in-region, we don't need to
+ ;; manipulate the undo tree at all
+ (if (undo-tree-reverting-redo-in-region-p start end)
+ t ; return t to indicate success
+
+ ;; We build the `region-changeset' and `delta-list' lists forwards, using
+ ;; pointers `r' and `d' to the penultimate element of the list. So that we
+ ;; don't have to treat the first element differently, we prepend a dummy
+ ;; leading nil to the lists, and have the pointers point to that
+ ;; initially.
+ ;; Note: using '(nil) instead of (list nil) in the `let*' results in
+ ;; bizarre errors when the code is byte-compiled, where parts of the
+ ;; lists appear to survive across different calls to this function.
+ ;; An obscure byte-compiler bug, perhaps?
+ (let* ((region-changeset (list nil))
+ (r region-changeset)
+ (delta-list (list nil))
+ (d delta-list)
+ (node (undo-tree-current buffer-undo-tree))
+ (repeated-undo-in-region
+ (undo-tree-repeated-undo-in-region-p start end))
+ undo-adjusted-markers ; `undo-elt-in-region' expects this
+ fragment splice original-fragment original-splice original-current
+ got-visible-elt undo-list elt)
+
+ ;; --- initialisation ---
+ (cond
+ ;; if this is a repeated undo in the same region, start pulling changes
+ ;; from NODE at which undo-in-region branch iss attached, and detatch
+ ;; the branch, using it as initial FRAGMENT of branch being constructed
+ (repeated-undo-in-region
+ (setq original-current node
+ fragment (car (undo-tree-node-next node))
+ splice node)
+ ;; undo up to node at which undo-in-region branch is attached
+ ;; (recognizable as first node with more than one branch)
+ (let ((mark-active nil))
+ (while (= (length (undo-tree-node-next node)) 1)
+ (undo-tree-undo-1)
+ (setq fragment node
+ node (undo-tree-current buffer-undo-tree))))
+ (when (eq splice node) (setq splice nil))
+ ;; detatch undo-in-region branch
+ (setf (undo-tree-node-next node)
+ (delq fragment (undo-tree-node-next node))
+ (undo-tree-node-previous fragment) nil
+ original-fragment fragment
+ original-splice node))
+
+ ;; if this is a new undo-in-region, initial FRAGMENT is a copy of all
+ ;; nodes below the current one in the active branch
+ ((undo-tree-node-next node)
+ (setq fragment (undo-tree-make-node nil nil)
+ splice fragment)
+ (while (setq node (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node)))
+ (push (undo-tree-make-node
+ splice
+ (undo-copy-list (undo-tree-node-undo node))
+ (undo-copy-list (undo-tree-node-redo node)))
+ (undo-tree-node-next splice))
+ (setq splice (car (undo-tree-node-next splice))))
+ (setq fragment (car (undo-tree-node-next fragment))
+ splice nil
+ node (undo-tree-current buffer-undo-tree))))
+
+
+ ;; --- pull undo-in-region elements into branch ---
+ ;; work backwards up tree, pulling out undo elements within region until
+ ;; we've got one that undoes a visible change (insertion or deletion)
+ (catch 'abort
+ (while (and (not got-visible-elt) node (undo-tree-node-undo node))
+ ;; we cons a dummy nil element on the front of the changeset so that
+ ;; we can conveniently remove the first (real) element from the
+ ;; changeset if we need to; the leading nil is removed once we're
+ ;; done with this changeset
+ (setq undo-list (cons nil (undo-copy-list (undo-tree-node-undo node)))
+ elt (cadr undo-list))
+ (if fragment
+ (progn
+ (setq fragment (undo-tree-grow-backwards fragment undo-list))
+ (unless splice (setq splice fragment)))
+ (setq fragment (undo-tree-make-node nil undo-list))
+ (setq splice fragment))
+
+ (while elt
+ (cond
+ ;; keep elements within region
+ ((undo-elt-in-region elt start end)
+ ;; set flag if kept element is visible (insertion or deletion)
+ (when (and (consp elt)
+ (or (stringp (car elt)) (integerp (car elt))))
+ (setq got-visible-elt t))
+ ;; adjust buffer positions in elements previously undone before
+ ;; kept element, as kept element will now be undone first
+ (undo-tree-adjust-elements-to-elt splice elt)
+ ;; move kept element to undo-in-region changeset, adjusting its
+ ;; buffer position as it will now be undone first
+ (setcdr r (list (undo-tree-apply-deltas elt (cdr delta-list))))
+ (setq r (cdr r))
+ (setcdr undo-list (cddr undo-list)))
+
+ ;; discard "was unmodified" elements
+ ;; FIXME: deal properly with these
+ ((and (consp elt) (eq (car elt) t))
+ (setcdr undo-list (cddr undo-list)))
+
+ ;; if element crosses region, we can't pull any more elements
+ ((undo-elt-crosses-region elt start end)
+ ;; if we've found a visible element, it must be earlier in
+ ;; current node's changeset; stop pulling elements (null
+ ;; `undo-list' and non-nil `got-visible-elt' cause loop to exit)
+ (if got-visible-elt
+ (setq undo-list nil)
+ ;; if we haven't found a visible element yet, pulling
+ ;; undo-in-region branch has failed
+ (setq region-changeset nil)
+ (throw 'abort t)))
+
+ ;; if rejecting element, add its delta (if any) to the list
+ (t
+ (let ((delta (undo-delta elt)))
+ (when (/= 0 (cdr delta))
+ (setcdr d (list delta))
+ (setq d (cdr d))))
+ (setq undo-list (cdr undo-list))))
+
+ ;; process next element of current changeset
+ (setq elt (cadr undo-list)))
+
+ ;; if there are remaining elements in changeset, remove dummy nil
+ ;; from front
+ (if (cadr (undo-tree-node-undo fragment))
+ (pop (undo-tree-node-undo fragment))
+ ;; otherwise, if we've kept all elements in changeset, discard
+ ;; empty changeset
+ (when (eq splice fragment) (setq splice nil))
+ (setq fragment (car (undo-tree-node-next fragment))))
+ ;; process changeset from next node up the tree
+ (setq node (undo-tree-node-previous node))))
+
+ ;; pop dummy nil from front of `region-changeset'
+ (setq region-changeset (cdr region-changeset))
+
+
+ ;; --- integrate branch into tree ---
+ ;; if no undo-in-region elements were found, restore undo tree
+ (if (null region-changeset)
+ (when original-current
+ (push original-fragment (undo-tree-node-next original-splice))
+ (setf (undo-tree-node-branch original-splice) 0
+ (undo-tree-node-previous original-fragment) original-splice)
+ (let ((mark-active nil))
+ (while (not (eq (undo-tree-current buffer-undo-tree)
+ original-current))
+ (undo-tree-redo-1)))
+ nil) ; return nil to indicate failure
+
+ ;; otherwise...
+ ;; need to undo up to node where new branch will be attached, to
+ ;; ensure redo entries are populated, and then redo back to where we
+ ;; started
+ (let ((mark-active nil)
+ (current (undo-tree-current buffer-undo-tree)))
+ (while (not (eq (undo-tree-current buffer-undo-tree) node))
+ (undo-tree-undo-1))
+ (while (not (eq (undo-tree-current buffer-undo-tree) current))
+ (undo-tree-redo-1)))
+
+ (cond
+ ;; if there's no remaining fragment, just create undo-in-region node
+ ;; and attach it to parent of last node from which elements were
+ ;; pulled
+ ((null fragment)
+ (setq fragment (undo-tree-make-node node region-changeset))
+ (push fragment (undo-tree-node-next node))
+ (setf (undo-tree-node-branch node) 0)
+ ;; set current node to undo-in-region node
+ (setf (undo-tree-current buffer-undo-tree) fragment))
+
+ ;; if no splice point has been set, add undo-in-region node to top of
+ ;; fragment and attach it to parent of last node from which elements
+ ;; were pulled
+ ((null splice)
+ (setq fragment (undo-tree-grow-backwards fragment region-changeset))
+ (push fragment (undo-tree-node-next node))
+ (setf (undo-tree-node-branch node) 0
+ (undo-tree-node-previous fragment) node)
+ ;; set current node to undo-in-region node
+ (setf (undo-tree-current buffer-undo-tree) fragment))
+
+ ;; if fragment contains nodes, attach fragment to parent of last node
+ ;; from which elements were pulled, and splice in undo-in-region node
+ (t
+ (setf (undo-tree-node-previous fragment) node)
+ (push fragment (undo-tree-node-next node))
+ (setf (undo-tree-node-branch node) 0)
+ ;; if this is a repeated undo-in-region, then we've left the current
+ ;; node at the original splice-point; we need to set the current
+ ;; node to the equivalent node on the undo-in-region branch and redo
+ ;; back to where we started
+ (when repeated-undo-in-region
+ (setf (undo-tree-current buffer-undo-tree)
+ (undo-tree-node-previous original-fragment))
+ (let ((mark-active nil))
+ (while (not (eq (undo-tree-current buffer-undo-tree) splice))
+ (undo-tree-redo-1 nil 'preserve-undo))))
+ ;; splice new undo-in-region node into fragment
+ (setq node (undo-tree-make-node nil region-changeset))
+ (undo-tree-splice-node node splice)
+ ;; set current node to undo-in-region node
+ (setf (undo-tree-current buffer-undo-tree) node)))
+
+ ;; update undo-tree size
+ (setq node (undo-tree-node-previous fragment))
+ (while (progn
+ (and (setq node (car (undo-tree-node-next node)))
+ (not (eq node original-fragment))
+ (incf (undo-tree-count buffer-undo-tree))
+ (incf (undo-tree-size buffer-undo-tree)
+ (+ (undo-list-byte-size (undo-tree-node-undo node))
+ (undo-list-byte-size (undo-tree-node-redo node)))))))
+ t) ; indicate undo-in-region branch was successfully pulled
+ )))
+
+
+
+(defun undo-tree-pull-redo-in-region-branch (start end)
+ ;; Pull out entries from redo changesets to create a new redo-in-region
+ ;; branch, which redoes changeset entries lying between START and END first,
+ ;; followed by remaining entries from the changesets. Repeated calls will,
+ ;; if appropriate, extend the current redo-in-region branch rather than
+ ;; creating a new one.
+
+ ;; if we're just reverting the last undo-in-region, we don't need to
+ ;; manipulate the undo tree at all
+ (if (undo-tree-reverting-undo-in-region-p start end)
+ t ; return t to indicate success
+
+ ;; We build the `region-changeset' and `delta-list' lists forwards, using
+ ;; pointers `r' and `d' to the penultimate element of the list. So that we
+ ;; don't have to treat the first element differently, we prepend a dummy
+ ;; leading nil to the lists, and have the pointers point to that
+ ;; initially.
+ ;; Note: using '(nil) instead of (list nil) in the `let*' causes bizarre
+ ;; errors when the code is byte-compiled, where parts of the lists
+ ;; appear to survive across different calls to this function. An
+ ;; obscure byte-compiler bug, perhaps?
+ (let* ((region-changeset (list nil))
+ (r region-changeset)
+ (delta-list (list nil))
+ (d delta-list)
+ (node (undo-tree-current buffer-undo-tree))
+ (repeated-redo-in-region
+ (undo-tree-repeated-redo-in-region-p start end))
+ undo-adjusted-markers ; `undo-elt-in-region' expects this
+ fragment splice got-visible-elt redo-list elt)
+
+ ;; --- inisitalisation ---
+ (cond
+ ;; if this is a repeated redo-in-region, detach fragment below current
+ ;; node
+ (repeated-redo-in-region
+ (when (setq fragment (car (undo-tree-node-next node)))
+ (setf (undo-tree-node-previous fragment) nil
+ (undo-tree-node-next node)
+ (delq fragment (undo-tree-node-next node)))))
+ ;; if this is a new redo-in-region, initial fragment is a copy of all
+ ;; nodes below the current one in the active branch
+ ((undo-tree-node-next node)
+ (setq fragment (undo-tree-make-node nil nil)
+ splice fragment)
+ (while (setq node (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node)))
+ (push (undo-tree-make-node
+ splice nil
+ (undo-copy-list (undo-tree-node-redo node)))
+ (undo-tree-node-next splice))
+ (setq splice (car (undo-tree-node-next splice))))
+ (setq fragment (car (undo-tree-node-next fragment)))))
+
+
+ ;; --- pull redo-in-region elements into branch ---
+ ;; work down fragment, pulling out redo elements within region until
+ ;; we've got one that redoes a visible change (insertion or deletion)
+ (setq node fragment)
+ (catch 'abort
+ (while (and (not got-visible-elt) node (undo-tree-node-redo node))
+ ;; we cons a dummy nil element on the front of the changeset so that
+ ;; we can conveniently remove the first (real) element from the
+ ;; changeset if we need to; the leading nil is removed once we're
+ ;; done with this changeset
+ (setq redo-list (push nil (undo-tree-node-redo node))
+ elt (cadr redo-list))
+ (while elt
+ (cond
+ ;; keep elements within region
+ ((undo-elt-in-region elt start end)
+ ;; set flag if kept element is visible (insertion or deletion)
+ (when (and (consp elt)
+ (or (stringp (car elt)) (integerp (car elt))))
+ (setq got-visible-elt t))
+ ;; adjust buffer positions in elements previously redone before
+ ;; kept element, as kept element will now be redone first
+ (undo-tree-adjust-elements-to-elt fragment elt t)
+ ;; move kept element to redo-in-region changeset, adjusting its
+ ;; buffer position as it will now be redone first
+ (setcdr r (list (undo-tree-apply-deltas elt (cdr delta-list) -1)))
+ (setq r (cdr r))
+ (setcdr redo-list (cddr redo-list)))
+
+ ;; discard "was unmodified" elements
+ ;; FIXME: deal properly with these
+ ((and (consp elt) (eq (car elt) t))
+ (setcdr redo-list (cddr redo-list)))
+
+ ;; if element crosses region, we can't pull any more elements
+ ((undo-elt-crosses-region elt start end)
+ ;; if we've found a visible element, it must be earlier in
+ ;; current node's changeset; stop pulling elements (null
+ ;; `redo-list' and non-nil `got-visible-elt' cause loop to exit)
+ (if got-visible-elt
+ (setq redo-list nil)
+ ;; if we haven't found a visible element yet, pulling
+ ;; redo-in-region branch has failed
+ (setq region-changeset nil)
+ (throw 'abort t)))
+
+ ;; if rejecting element, add its delta (if any) to the list
+ (t
+ (let ((delta (undo-delta elt)))
+ (when (/= 0 (cdr delta))
+ (setcdr d (list delta))
+ (setq d (cdr d))))
+ (setq redo-list (cdr redo-list))))
+
+ ;; process next element of current changeset
+ (setq elt (cadr redo-list)))
+
+ ;; if there are remaining elements in changeset, remove dummy nil
+ ;; from front
+ (if (cadr (undo-tree-node-redo node))
+ (pop (undo-tree-node-undo node))
+ ;; otherwise, if we've kept all elements in changeset, discard
+ ;; empty changeset
+ (if (eq fragment node)
+ (setq fragment (car (undo-tree-node-next fragment)))
+ (undo-tree-snip-node node)))
+ ;; process changeset from next node in fragment
+ (setq node (car (undo-tree-node-next node)))))
+
+ ;; pop dummy nil from front of `region-changeset'
+ (setq region-changeset (cdr region-changeset))
+
+
+ ;; --- integrate branch into tree ---
+ (setq node (undo-tree-current buffer-undo-tree))
+ ;; if no redo-in-region elements were found, restore undo tree
+ (if (null (car region-changeset))
+ (when (and repeated-redo-in-region fragment)
+ (push fragment (undo-tree-node-next node))
+ (setf (undo-tree-node-branch node) 0
+ (undo-tree-node-previous fragment) node)
+ nil) ; return nil to indicate failure
+
+ ;; otherwise, add redo-in-region node to top of fragment, and attach
+ ;; it below current node
+ (setq fragment
+ (if fragment
+ (undo-tree-grow-backwards fragment nil region-changeset)
+ (undo-tree-make-node nil nil region-changeset)))
+ (push fragment (undo-tree-node-next node))
+ (setf (undo-tree-node-branch node) 0
+ (undo-tree-node-previous fragment) node)
+ ;; update undo-tree size
+ (unless repeated-redo-in-region
+ (setq node fragment)
+ (while (and (setq node (car (undo-tree-node-next node)))
+ (incf (undo-tree-count buffer-undo-tree))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size
+ (undo-tree-node-redo node))))))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo fragment)))
+ t) ; indicate redo-in-region branch was successfully pulled
+ )))
+
+
+
+(defun undo-tree-adjust-elements-to-elt (node undo-elt &optional below)
+ "Adjust buffer positions of undo elements, starting at NODE's
+and going up the tree (or down the active branch if BELOW is
+non-nil) and through the nodes' undo elements until we reach
+UNDO-ELT. UNDO-ELT must appear somewhere in the undo changeset
+of either NODE itself or some node above it in the tree."
+ (let ((delta (list (undo-delta undo-elt)))
+ (undo-list (undo-tree-node-undo node)))
+ ;; adjust elements until we reach UNDO-ELT
+ (while (and (car undo-list)
+ (not (eq (car undo-list) undo-elt)))
+ (setcar undo-list
+ (undo-tree-apply-deltas (car undo-list) delta -1))
+ ;; move to next undo element in list, or to next node if we've run out
+ ;; of elements
+ (unless (car (setq undo-list (cdr undo-list)))
+ (if below
+ (setq node (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node)))
+ (setq node (undo-tree-node-previous node)))
+ (setq undo-list (undo-tree-node-undo node))))))
+
+
+
+(defun undo-tree-apply-deltas (undo-elt deltas &optional sgn)
+ ;; Apply DELTAS in order to UNDO-ELT, multiplying deltas by SGN
+ ;; (only useful value for SGN is -1).
+ (let (position offset)
+ (dolist (delta deltas)
+ (setq position (car delta)
+ offset (* (cdr delta) (or sgn 1)))
+ (cond
+ ;; POSITION
+ ((integerp undo-elt)
+ (when (>= undo-elt position)
+ (setq undo-elt (- undo-elt offset))))
+ ;; nil (or any other atom)
+ ((atom undo-elt))
+ ;; (TEXT . POSITION)
+ ((stringp (car undo-elt))
+ (let ((text-pos (abs (cdr undo-elt)))
+ (point-at-end (< (cdr undo-elt) 0)))
+ (if (>= text-pos position)
+ (setcdr undo-elt (* (if point-at-end -1 1)
+ (- text-pos offset))))))
+ ;; (BEGIN . END)
+ ((integerp (car undo-elt))
+ (when (>= (car undo-elt) position)
+ (setcar undo-elt (- (car undo-elt) offset))
+ (setcdr undo-elt (- (cdr undo-elt) offset))))
+ ;; (nil PROPERTY VALUE BEG . END)
+ ((null (car undo-elt))
+ (let ((tail (nthcdr 3 undo-elt)))
+ (when (>= (car tail) position)
+ (setcar tail (- (car tail) offset))
+ (setcdr tail (- (cdr tail) offset)))))
+ ))
+ undo-elt))
+
+
+
+(defun undo-tree-repeated-undo-in-region-p (start end)
+ ;; Return non-nil if undo-in-region between START and END is a repeated
+ ;; undo-in-region
+ (let ((node (undo-tree-current buffer-undo-tree)))
+ (and (setq node
+ (nth (undo-tree-node-branch node) (undo-tree-node-next node)))
+ (eq (undo-tree-node-undo-beginning node) start)
+ (eq (undo-tree-node-undo-end node) end))))
+
+
+(defun undo-tree-repeated-redo-in-region-p (start end)
+ ;; Return non-nil if undo-in-region between START and END is a repeated
+ ;; undo-in-region
+ (let ((node (undo-tree-current buffer-undo-tree)))
+ (and (eq (undo-tree-node-redo-beginning node) start)
+ (eq (undo-tree-node-redo-end node) end))))
+
+
+;; Return non-nil if undo-in-region between START and END is simply
+;; reverting the last redo-in-region
+(defalias 'undo-tree-reverting-undo-in-region-p
+ 'undo-tree-repeated-undo-in-region-p)
+
+
+;; Return non-nil if redo-in-region between START and END is simply
+;; reverting the last undo-in-region
+(defalias 'undo-tree-reverting-redo-in-region-p
+ 'undo-tree-repeated-redo-in-region-p)
+
+
+
+\f
+;;; =====================================================================
+;;; Undo-tree commands
+
+;;;###autoload
+(define-minor-mode undo-tree-mode
+ "Toggle undo-tree mode.
+With no argument, this command toggles the mode.
+A positive prefix argument turns the mode on.
+A negative prefix argument turns it off.
+
+Undo-tree-mode replaces Emacs' standard undo feature with a more
+powerful yet easier to use version, that treats the undo history
+as what it is: a tree.
+
+The following keys are available in `undo-tree-mode':
+
+ \\{undo-tree-map}
+
+Within the undo-tree visualizer, the following keys are available:
+
+ \\{undo-tree-visualizer-mode-map}"
+
+ nil ; init value
+ undo-tree-mode-lighter ; lighter
+ undo-tree-map ; keymap
+
+ ;; if disabling `undo-tree-mode', rebuild `buffer-undo-list' from tree so
+ ;; Emacs undo can work
+ (when (not undo-tree-mode)
+ (undo-list-rebuild-from-tree)
+ (setq buffer-undo-tree nil)))
+
+
+(defun turn-on-undo-tree-mode (&optional print-message)
+ "Enable `undo-tree-mode' in the current buffer, when appropriate.
+Some major modes implement their own undo system, which should
+not normally be overridden by `undo-tree-mode'. This command does
+not enable `undo-tree-mode' in such buffers. If you want to force
+`undo-tree-mode' to be enabled regardless, use (undo-tree-mode 1)
+instead.
+
+The heuristic used to detect major modes in which
+`undo-tree-mode' should not be used is to check whether either
+the `undo' command has been remapped, or the default undo
+keybindings (C-/ and C-_) have been overridden somewhere other
+than in the global map. In addition, `undo-tree-mode' will not be
+enabled if the buffer's `major-mode' appears in
+`undo-tree-incompatible-major-modes'."
+ (interactive "p")
+ (if (or (key-binding [remap undo])
+ (undo-tree-overridden-undo-bindings-p)
+ (memq major-mode undo-tree-incompatible-major-modes))
+ (when print-message
+ (message "Buffer does not support undo-tree-mode;\
+ undo-tree-mode NOT enabled"))
+ (undo-tree-mode 1)))
+
+
+(defun undo-tree-overridden-undo-bindings-p ()
+ "Returns t if default undo bindings are overridden, nil otherwise.
+Checks if either of the default undo key bindings (\"C-/\" or
+\"C-_\") are overridden in the current buffer by any keymap other
+than the global one. (So global redefinitions of the default undo
+key bindings do not count.)"
+ (let ((binding1 (lookup-key (current-global-map) [?\C-/]))
+ (binding2 (lookup-key (current-global-map) [?\C-_])))
+ (global-set-key [?\C-/] 'undo)
+ (global-set-key [?\C-_] 'undo)
+ (unwind-protect
+ (or (and (key-binding [?\C-/])
+ (not (eq (key-binding [?\C-/]) 'undo)))
+ (and (key-binding [?\C-_])
+ (not (eq (key-binding [?\C-_]) 'undo))))
+ (global-set-key [?\C-/] binding1)
+ (global-set-key [?\C-_] binding2))))
+
+
+;;;###autoload
+(define-globalized-minor-mode global-undo-tree-mode
+ undo-tree-mode turn-on-undo-tree-mode)
+
+
+
+(defun undo-tree-undo (&optional arg)
+ "Undo changes.
+Repeat this command to undo more changes.
+A numeric ARG serves as a repeat count.
+
+In Transient Mark mode when the mark is active, only undo changes
+within the current region. Similarly, when not in Transient Mark
+mode, just \\[universal-argument] as an argument limits undo to
+changes within the current region."
+ (interactive "*P")
+ ;; throw error if undo is disabled in buffer
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ (undo-tree-undo-1 arg)
+ ;; inform user if at branch point
+ (when (> (undo-tree-num-branches) 1) (message "Undo branch point!")))
+
+
+(defun undo-tree-undo-1 (&optional arg preserve-redo preserve-timestamps)
+ ;; Internal undo function. An active mark in `transient-mark-mode', or
+ ;; non-nil ARG otherwise, enables undo-in-region. Non-nil PRESERVE-REDO
+ ;; causes the existing redo record to be preserved, rather than replacing it
+ ;; with the new one generated by undoing. Non-nil PRESERVE-TIMESTAMPS
+ ;; disables updating of timestamps in visited undo-tree nodes. (This latter
+ ;; should *only* be used when temporarily visiting another undo state and
+ ;; immediately returning to the original state afterwards. Otherwise, it
+ ;; could cause history-discarding errors.)
+ (let ((undo-in-progress t)
+ (undo-in-region (and undo-tree-enable-undo-in-region
+ (or (region-active-p)
+ (and arg (not (numberp arg))))))
+ pos current)
+ ;; transfer entries accumulated in `buffer-undo-list' to
+ ;; `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+
+ (dotimes (i (or (and (numberp arg) (prefix-numeric-value arg)) 1))
+ ;; check if at top of undo tree
+ (unless (undo-tree-node-previous (undo-tree-current buffer-undo-tree))
+ (user-error "No further undo information"))
+
+ ;; if region is active, or a non-numeric prefix argument was supplied,
+ ;; try to pull out a new branch of changes affecting the region
+ (when (and undo-in-region
+ (not (undo-tree-pull-undo-in-region-branch
+ (region-beginning) (region-end))))
+ (user-error "No further undo information for region"))
+
+ ;; remove any GC'd elements from node's undo list
+ (setq current (undo-tree-current buffer-undo-tree))
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current)))
+ (setf (undo-tree-node-undo current)
+ (undo-list-clean-GCd-elts (undo-tree-node-undo current)))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current)))
+ ;; undo one record from undo tree
+ (when undo-in-region
+ (setq pos (set-marker (make-marker) (point)))
+ (set-marker-insertion-type pos t))
+ (primitive-undo 1 (undo-tree-copy-list (undo-tree-node-undo current)))
+ (undo-boundary)
+
+ ;; if preserving old redo record, discard new redo entries that
+ ;; `primitive-undo' has added to `buffer-undo-list', and remove any GC'd
+ ;; elements from node's redo list
+ (if preserve-redo
+ (progn
+ (undo-list-pop-changeset)
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current)))
+ (setf (undo-tree-node-redo current)
+ (undo-list-clean-GCd-elts (undo-tree-node-redo current)))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current))))
+ ;; otherwise, record redo entries that `primitive-undo' has added to
+ ;; `buffer-undo-list' in current node's redo record, replacing
+ ;; existing entry if one already exists
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current)))
+ (setf (undo-tree-node-redo current)
+ (undo-list-pop-changeset 'discard-pos))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current))))
+
+ ;; rewind current node and update timestamp
+ (setf (undo-tree-current buffer-undo-tree)
+ (undo-tree-node-previous (undo-tree-current buffer-undo-tree)))
+ (unless preserve-timestamps
+ (setf (undo-tree-node-timestamp (undo-tree-current buffer-undo-tree))
+ (current-time)))
+
+ ;; if undoing-in-region, record current node, region and direction so we
+ ;; can tell if undo-in-region is repeated, and re-activate mark if in
+ ;; `transient-mark-mode'; if not, erase any leftover data
+ (if (not undo-in-region)
+ (undo-tree-node-clear-region-data current)
+ (goto-char pos)
+ ;; note: we deliberately want to store the region information in the
+ ;; node *below* the now current one
+ (setf (undo-tree-node-undo-beginning current) (region-beginning)
+ (undo-tree-node-undo-end current) (region-end))
+ (set-marker pos nil)))
+
+ ;; undo deactivates mark unless undoing-in-region
+ (setq deactivate-mark (not undo-in-region))))
+
+
+
+(defun undo-tree-redo (&optional arg)
+ "Redo changes. A numeric ARG serves as a repeat count.
+
+In Transient Mark mode when the mark is active, only redo changes
+within the current region. Similarly, when not in Transient Mark
+mode, just \\[universal-argument] as an argument limits redo to
+changes within the current region."
+ (interactive "*P")
+ ;; throw error if undo is disabled in buffer
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ (undo-tree-redo-1 arg)
+ ;; inform user if at branch point
+ (when (> (undo-tree-num-branches) 1) (message "Undo branch point!")))
+
+
+(defun undo-tree-redo-1 (&optional arg preserve-undo preserve-timestamps)
+ ;; Internal redo function. An active mark in `transient-mark-mode', or
+ ;; non-nil ARG otherwise, enables undo-in-region. Non-nil PRESERVE-UNDO
+ ;; causes the existing redo record to be preserved, rather than replacing it
+ ;; with the new one generated by undoing. Non-nil PRESERVE-TIMESTAMPS
+ ;; disables updating of timestamps in visited undo-tree nodes. (This latter
+ ;; should *only* be used when temporarily visiting another undo state and
+ ;; immediately returning to the original state afterwards. Otherwise, it
+ ;; could cause history-discarding errors.)
+ (let ((undo-in-progress t)
+ (redo-in-region (and undo-tree-enable-undo-in-region
+ (or (region-active-p)
+ (and arg (not (numberp arg))))))
+ pos current)
+ ;; transfer entries accumulated in `buffer-undo-list' to
+ ;; `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+
+ (dotimes (i (or (and (numberp arg) (prefix-numeric-value arg)) 1))
+ ;; check if at bottom of undo tree
+ (when (null (undo-tree-node-next (undo-tree-current buffer-undo-tree)))
+ (user-error "No further redo information"))
+
+ ;; if region is active, or a non-numeric prefix argument was supplied,
+ ;; try to pull out a new branch of changes affecting the region
+ (when (and redo-in-region
+ (not (undo-tree-pull-redo-in-region-branch
+ (region-beginning) (region-end))))
+ (user-error "No further redo information for region"))
+
+ ;; get next node (but DON'T advance current node in tree yet, in case
+ ;; redoing fails)
+ (setq current (undo-tree-current buffer-undo-tree)
+ current (nth (undo-tree-node-branch current)
+ (undo-tree-node-next current)))
+ ;; remove any GC'd elements from node's redo list
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current)))
+ (setf (undo-tree-node-redo current)
+ (undo-list-clean-GCd-elts (undo-tree-node-redo current)))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-redo current)))
+ ;; redo one record from undo tree
+ (when redo-in-region
+ (setq pos (set-marker (make-marker) (point)))
+ (set-marker-insertion-type pos t))
+ (primitive-undo 1 (undo-tree-copy-list (undo-tree-node-redo current)))
+ (undo-boundary)
+ ;; advance current node in tree
+ (setf (undo-tree-current buffer-undo-tree) current)
+
+ ;; if preserving old undo record, discard new undo entries that
+ ;; `primitive-undo' has added to `buffer-undo-list', and remove any GC'd
+ ;; elements from node's redo list
+ (if preserve-undo
+ (progn
+ (undo-list-pop-changeset)
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current)))
+ (setf (undo-tree-node-undo current)
+ (undo-list-clean-GCd-elts (undo-tree-node-undo current)))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current))))
+ ;; otherwise, record undo entries that `primitive-undo' has added to
+ ;; `buffer-undo-list' in current node's undo record, replacing
+ ;; existing entry if one already exists
+ (decf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current)))
+ (setf (undo-tree-node-undo current)
+ (undo-list-pop-changeset 'discard-pos))
+ (incf (undo-tree-size buffer-undo-tree)
+ (undo-list-byte-size (undo-tree-node-undo current))))
+
+ ;; update timestamp
+ (unless preserve-timestamps
+ (setf (undo-tree-node-timestamp current) (current-time)))
+
+ ;; if redoing-in-region, record current node, region and direction so we
+ ;; can tell if redo-in-region is repeated, and re-activate mark if in
+ ;; `transient-mark-mode'
+ (if (not redo-in-region)
+ (undo-tree-node-clear-region-data current)
+ (goto-char pos)
+ (setf (undo-tree-node-redo-beginning current) (region-beginning)
+ (undo-tree-node-redo-end current) (region-end))
+ (set-marker pos nil)))
+
+ ;; redo deactivates the mark unless redoing-in-region
+ (setq deactivate-mark (not redo-in-region))))
+
+
+
+(defun undo-tree-switch-branch (branch)
+ "Switch to a different BRANCH of the undo tree.
+This will affect which branch to descend when *redoing* changes
+using `undo-tree-redo'."
+ (interactive (list (or (and prefix-arg (prefix-numeric-value prefix-arg))
+ (and (not (eq buffer-undo-list t))
+ (or (undo-list-transfer-to-tree) t)
+ (let ((b (undo-tree-node-branch
+ (undo-tree-current
+ buffer-undo-tree))))
+ (cond
+ ;; switch to other branch if only 2
+ ((= (undo-tree-num-branches) 2) (- 1 b))
+ ;; prompt if more than 2
+ ((> (undo-tree-num-branches) 2)
+ (read-number
+ (format "Branch (0-%d, on %d): "
+ (1- (undo-tree-num-branches)) b)))
+ ))))))
+ ;; throw error if undo is disabled in buffer
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ ;; sanity check branch number
+ (when (<= (undo-tree-num-branches) 1)
+ (user-error "Not at undo branch point"))
+ (when (or (< branch 0) (> branch (1- (undo-tree-num-branches))))
+ (user-error "Invalid branch number"))
+ ;; transfer entries accumulated in `buffer-undo-list' to `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+ ;; switch branch
+ (setf (undo-tree-node-branch (undo-tree-current buffer-undo-tree))
+ branch)
+ (message "Switched to branch %d" branch))
+
+
+(defun undo-tree-set (node &optional preserve-timestamps)
+ ;; Set buffer to state corresponding to NODE. Returns intersection point
+ ;; between path back from current node and path back from selected NODE.
+ ;; Non-nil PRESERVE-TIMESTAMPS disables updating of timestamps in visited
+ ;; undo-tree nodes. (This should *only* be used when temporarily visiting
+ ;; another undo state and immediately returning to the original state
+ ;; afterwards. Otherwise, it could cause history-discarding errors.)
+ (let ((path (make-hash-table :test 'eq))
+ (n node))
+ (puthash (undo-tree-root buffer-undo-tree) t path)
+ ;; build list of nodes leading back from selected node to root, updating
+ ;; branches as we go to point down to selected node
+ (while (progn
+ (puthash n t path)
+ (when (undo-tree-node-previous n)
+ (setf (undo-tree-node-branch (undo-tree-node-previous n))
+ (undo-tree-position
+ n (undo-tree-node-next (undo-tree-node-previous n))))
+ (setq n (undo-tree-node-previous n)))))
+ ;; work backwards from current node until we intersect path back from
+ ;; selected node
+ (setq n (undo-tree-current buffer-undo-tree))
+ (while (not (gethash n path))
+ (setq n (undo-tree-node-previous n)))
+ ;; ascend tree until intersection node
+ (while (not (eq (undo-tree-current buffer-undo-tree) n))
+ (undo-tree-undo-1 nil nil preserve-timestamps))
+ ;; descend tree until selected node
+ (while (not (eq (undo-tree-current buffer-undo-tree) node))
+ (undo-tree-redo-1 nil nil preserve-timestamps))
+ n)) ; return intersection node
+
+
+
+(defun undo-tree-save-state-to-register (register)
+ "Store current undo-tree state to REGISTER.
+The saved state can be restored using
+`undo-tree-restore-state-from-register'.
+Argument is a character, naming the register."
+ (interactive "cUndo-tree state to register: ")
+ ;; throw error if undo is disabled in buffer
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ ;; transfer entries accumulated in `buffer-undo-list' to `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+ ;; save current node to REGISTER
+ (set-register
+ register (registerv-make
+ (undo-tree-make-register-data
+ (current-buffer) (undo-tree-current buffer-undo-tree))
+ :print-func 'undo-tree-register-data-print-func))
+ ;; record REGISTER in current node, for visualizer
+ (setf (undo-tree-node-register (undo-tree-current buffer-undo-tree))
+ register))
+
+
+
+(defun undo-tree-restore-state-from-register (register)
+ "Restore undo-tree state from REGISTER.
+The state must be saved using `undo-tree-save-state-to-register'.
+Argument is a character, naming the register."
+ (interactive "*cRestore undo-tree state from register: ")
+ ;; throw error if undo is disabled in buffer, or if register doesn't contain
+ ;; an undo-tree node
+ (let ((data (registerv-data (get-register register))))
+ (cond
+ ((eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ ((not (undo-tree-register-data-p data))
+ (user-error "Register doesn't contain undo-tree state"))
+ ((not (eq (current-buffer) (undo-tree-register-data-buffer data)))
+ (user-error "Register contains undo-tree state for a different buffer")))
+ ;; transfer entries accumulated in `buffer-undo-list' to `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+ ;; restore buffer state corresponding to saved node
+ (undo-tree-set (undo-tree-register-data-node data))))
+
+
+
+\f
+;;; =====================================================================
+;;; Persistent storage commands
+
+(defun undo-tree-make-history-save-file-name (file)
+ "Create the undo history file name for FILE.
+Normally this is the file's name with \".\" prepended and
+\".~undo-tree~\" appended.
+
+A match for FILE is sought in `undo-tree-history-directory-alist'
+\(see the documentation of that variable for details\). If the
+directory for the backup doesn't exist, it is created."
+ (let* ((backup-directory-alist undo-tree-history-directory-alist)
+ (name (make-backup-file-name-1 file)))
+ (concat (file-name-directory name) "." (file-name-nondirectory name)
+ ".~undo-tree~")))
+
+
+(defun undo-tree-save-history (&optional filename overwrite)
+ "Store undo-tree history to file.
+
+If optional argument FILENAME is omitted, default save file is
+\".<buffer-file-name>.~undo-tree\" if buffer is visiting a file.
+Otherwise, prompt for one.
+
+If OVERWRITE is non-nil, any existing file will be overwritten
+without asking for confirmation."
+ (interactive)
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ (undo-list-transfer-to-tree)
+ (when (and buffer-undo-tree (not (eq buffer-undo-tree t)))
+ (condition-case nil
+ (undo-tree-kill-visualizer)
+ (error (undo-tree-clear-visualizer-data buffer-undo-tree)))
+ (let ((buff (current-buffer))
+ tree)
+ ;; get filename
+ (unless filename
+ (setq filename
+ (if buffer-file-name
+ (undo-tree-make-history-save-file-name buffer-file-name)
+ (expand-file-name (read-file-name "File to save in: ") nil))))
+ (when (or (not (file-exists-p filename))
+ overwrite
+ (yes-or-no-p (format "Overwrite \"%s\"? " filename)))
+ (unwind-protect
+ (progn
+ ;; transform undo-tree into non-circular structure, and make
+ ;; temporary copy
+ (undo-tree-decircle buffer-undo-tree)
+ (setq tree (copy-undo-tree buffer-undo-tree))
+ ;; discard undo-tree object pool before saving
+ (setf (undo-tree-object-pool tree) nil)
+ ;; print undo-tree to file
+ ;; NOTE: We use `with-temp-buffer' instead of `with-temp-file'
+ ;; to allow `auto-compression-mode' to take effect, in
+ ;; case user has overridden or advised the default
+ ;; `undo-tree-make-history-save-file-name' to add a
+ ;; compressed file extension.
+ (with-auto-compression-mode
+ (with-temp-buffer
+ (prin1 (sha1 buff) (current-buffer))
+ (terpri (current-buffer))
+ (let ((print-circle t)) (prin1 tree (current-buffer)))
+ (write-region nil nil filename))))
+ ;; restore circular undo-tree data structure
+ (undo-tree-recircle buffer-undo-tree))
+ ))))
+
+
+
+(defun undo-tree-load-history (&optional filename noerror)
+ "Load undo-tree history from file.
+
+If optional argument FILENAME is null, default load file is
+\".<buffer-file-name>.~undo-tree\" if buffer is visiting a file.
+Otherwise, prompt for one.
+
+If optional argument NOERROR is non-nil, return nil instead of
+signaling an error if file is not found."
+ (interactive)
+ ;; get filename
+ (unless filename
+ (setq filename
+ (if buffer-file-name
+ (undo-tree-make-history-save-file-name buffer-file-name)
+ (expand-file-name (read-file-name "File to load from: ") nil))))
+
+ ;; attempt to read undo-tree from FILENAME
+ (catch 'load-error
+ (unless (file-exists-p filename)
+ (if noerror
+ (throw 'load-error nil)
+ (error "File \"%s\" does not exist; could not load undo-tree history"
+ filename)))
+ (let (buff hash tree)
+ (setq buff (current-buffer))
+ (with-auto-compression-mode
+ (with-temp-buffer
+ (insert-file-contents filename)
+ (goto-char (point-min))
+ (condition-case nil
+ (setq hash (read (current-buffer)))
+ (error
+ (kill-buffer nil)
+ (funcall (if noerror 'message 'user-error)
+ "Error reading undo-tree history from \"%s\"" filename)
+ (throw 'load-error nil)))
+ (unless (string= (sha1 buff) hash)
+ (kill-buffer nil)
+ (funcall (if noerror 'message 'user-error)
+ "Buffer has been modified; could not load undo-tree history")
+ (throw 'load-error nil))
+ (condition-case nil
+ (setq tree (read (current-buffer)))
+ (error
+ (kill-buffer nil)
+ (funcall (if noerror 'message 'error)
+ "Error reading undo-tree history from \"%s\"" filename)
+ (throw 'load-error nil)))
+ (kill-buffer nil)))
+ ;; initialise empty undo-tree object pool
+ (setf (undo-tree-object-pool tree)
+ (make-hash-table :test 'eq :weakness 'value))
+ ;; restore circular undo-tree data structure
+ (undo-tree-recircle tree)
+ (setq buffer-undo-tree tree))))
+
+
+
+;; Versions of save/load functions for use in hooks
+(defun undo-tree-save-history-hook ()
+ (when (and undo-tree-mode undo-tree-auto-save-history
+ (not (eq buffer-undo-list t)))
+ (undo-tree-save-history nil t) nil))
+
+(defun undo-tree-load-history-hook ()
+ (when (and undo-tree-mode undo-tree-auto-save-history
+ (not (eq buffer-undo-list t))
+ (not revert-buffer-in-progress-p))
+ (undo-tree-load-history nil t)))
+
+
+
+\f
+;;; =====================================================================
+;;; Visualizer drawing functions
+
+(defun undo-tree-visualize ()
+ "Visualize the current buffer's undo tree."
+ (interactive "*")
+ (deactivate-mark)
+ ;; throw error if undo is disabled in buffer
+ (when (eq buffer-undo-list t)
+ (user-error "No undo information in this buffer"))
+ ;; transfer entries accumulated in `buffer-undo-list' to `buffer-undo-tree'
+ (undo-list-transfer-to-tree)
+ ;; add hook to kill visualizer buffer if original buffer is changed
+ (add-hook 'before-change-functions 'undo-tree-kill-visualizer nil t)
+ ;; prepare *undo-tree* buffer, then draw tree in it
+ (let ((undo-tree buffer-undo-tree)
+ (buff (current-buffer))
+ (display-buffer-mark-dedicated 'soft))
+ (switch-to-buffer-other-window
+ (get-buffer-create undo-tree-visualizer-buffer-name))
+ (setq undo-tree-visualizer-parent-buffer buff)
+ (setq undo-tree-visualizer-parent-mtime
+ (and (buffer-file-name buff)
+ (nth 5 (file-attributes (buffer-file-name buff)))))
+ (setq undo-tree-visualizer-initial-node (undo-tree-current undo-tree))
+ (setq undo-tree-visualizer-spacing
+ (undo-tree-visualizer-calculate-spacing))
+ (make-local-variable 'undo-tree-visualizer-timestamps)
+ (make-local-variable 'undo-tree-visualizer-diff)
+ (setq buffer-undo-tree undo-tree)
+ (undo-tree-visualizer-mode)
+ ;; FIXME; don't know why `undo-tree-visualizer-mode' clears this
+ (setq buffer-undo-tree undo-tree)
+ (set (make-local-variable 'undo-tree-visualizer-lazy-drawing)
+ (or (eq undo-tree-visualizer-lazy-drawing t)
+ (and (numberp undo-tree-visualizer-lazy-drawing)
+ (>= (undo-tree-count undo-tree)
+ undo-tree-visualizer-lazy-drawing))))
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-show-diff))
+ (let ((inhibit-read-only t)) (undo-tree-draw-tree undo-tree))))
+
+
+(defun undo-tree-kill-visualizer (&rest _dummy)
+ ;; Kill visualizer. Added to `before-change-functions' hook of original
+ ;; buffer when visualizer is invoked.
+ (unless (or undo-tree-inhibit-kill-visualizer
+ (null (get-buffer undo-tree-visualizer-buffer-name)))
+ (with-current-buffer undo-tree-visualizer-buffer-name
+ (undo-tree-visualizer-quit))))
+
+
+
+(defun undo-tree-draw-tree (undo-tree)
+ ;; Draw undo-tree in current buffer starting from NODE (or root if nil).
+ (let ((node (if undo-tree-visualizer-lazy-drawing
+ (undo-tree-current undo-tree)
+ (undo-tree-root undo-tree))))
+ (erase-buffer)
+ (setq undo-tree-visualizer-needs-extending-down nil
+ undo-tree-visualizer-needs-extending-up nil)
+ (undo-tree-clear-visualizer-data undo-tree)
+ (undo-tree-compute-widths node)
+ ;; lazy drawing starts vertically centred and displaced horizontally to
+ ;; the left (window-width/4), since trees will typically grow right
+ (if undo-tree-visualizer-lazy-drawing
+ (progn
+ (undo-tree-move-down (/ (window-height) 2))
+ (undo-tree-move-forward (max 2 (/ (window-width) 4)))) ; left margin
+ ;; non-lazy drawing starts in centre at top of buffer
+ (undo-tree-move-down 1) ; top margin
+ (undo-tree-move-forward
+ (max (/ (window-width) 2)
+ (+ (undo-tree-node-char-lwidth node)
+ ;; add space for left part of left-most time-stamp
+ (if undo-tree-visualizer-timestamps
+ (/ (- undo-tree-visualizer-spacing 4) 2)
+ 0)
+ 2)))) ; left margin
+ ;; link starting node to its representation in visualizer
+ (setf (undo-tree-node-marker node) (make-marker))
+ (set-marker-insertion-type (undo-tree-node-marker node) nil)
+ (move-marker (undo-tree-node-marker node) (point))
+ ;; draw undo-tree
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-default-face)
+ node-list)
+ (if (not undo-tree-visualizer-lazy-drawing)
+ (undo-tree-extend-down node t)
+ (undo-tree-extend-down node)
+ (undo-tree-extend-up node)
+ (setq node-list undo-tree-visualizer-needs-extending-down
+ undo-tree-visualizer-needs-extending-down nil)
+ (while node-list (undo-tree-extend-down (pop node-list)))))
+ ;; highlight active branch
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-active-branch-face))
+ (undo-tree-highlight-active-branch
+ (or undo-tree-visualizer-needs-extending-up
+ (undo-tree-root undo-tree))))
+ ;; highlight current node
+ (undo-tree-draw-node (undo-tree-current undo-tree) 'current)))
+
+
+(defun undo-tree-extend-down (node &optional bottom)
+ ;; Extend tree downwards starting from NODE and point. If BOTTOM is t,
+ ;; extend all the way down to the leaves. If BOTTOM is a node, extend down
+ ;; as far as that node. If BOTTOM is an integer, extend down as far as that
+ ;; line. Otherwise, only extend visible portion of tree. NODE is assumed to
+ ;; already have a node marker. Returns non-nil if anything was actually
+ ;; extended.
+ (let ((extended nil)
+ (cur-stack (list node))
+ next-stack)
+ ;; don't bother extending if BOTTOM specifies an already-drawn node
+ (unless (and (undo-tree-node-p bottom) (undo-tree-node-marker bottom))
+ ;; draw nodes layer by layer
+ (while (or cur-stack
+ (prog1 (setq cur-stack next-stack)
+ (setq next-stack nil)))
+ (setq node (pop cur-stack))
+ ;; if node is within range being drawn...
+ (if (or (eq bottom t)
+ (and (undo-tree-node-p bottom)
+ (not (eq (undo-tree-node-previous node) bottom)))
+ (and (integerp bottom)
+ (>= bottom (line-number-at-pos
+ (undo-tree-node-marker node))))
+ (and (null bottom)
+ (pos-visible-in-window-p (undo-tree-node-marker node)
+ nil t)))
+ ;; ...draw one layer of node's subtree (if not already drawn)
+ (progn
+ (unless (and (undo-tree-node-next node)
+ (undo-tree-node-marker
+ (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node))))
+ (goto-char (undo-tree-node-marker node))
+ (undo-tree-draw-subtree node)
+ (setq extended t))
+ (setq next-stack
+ (append (undo-tree-node-next node) next-stack)))
+ ;; ...otherwise, postpone drawing until later
+ (push node undo-tree-visualizer-needs-extending-down))))
+ extended))
+
+
+(defun undo-tree-extend-up (node &optional top)
+ ;; Extend tree upwards starting from NODE. If TOP is t, extend all the way
+ ;; to root. If TOP is a node, extend up as far as that node. If TOP is an
+ ;; integer, extend up as far as that line. Otherwise, only extend visible
+ ;; portion of tree. NODE is assumed to already have a node marker. Returns
+ ;; non-nil if anything was actually extended.
+ (let ((extended nil) parent)
+ ;; don't bother extending if TOP specifies an already-drawn node
+ (unless (and (undo-tree-node-p top) (undo-tree-node-marker top))
+ (while node
+ (setq parent (undo-tree-node-previous node))
+ ;; if we haven't reached root...
+ (if parent
+ ;; ...and node is within range being drawn...
+ (if (or (eq top t)
+ (and (undo-tree-node-p top) (not (eq node top)))
+ (and (integerp top)
+ (< top (line-number-at-pos
+ (undo-tree-node-marker node))))
+ (and (null top)
+ ;; NOTE: we check point in case window-start is outdated
+ (< (min (line-number-at-pos (point))
+ (line-number-at-pos (window-start)))
+ (line-number-at-pos
+ (undo-tree-node-marker node)))))
+ ;; ...and it hasn't already been drawn
+ (when (not (undo-tree-node-marker parent))
+ ;; link parent node to its representation in visualizer
+ (undo-tree-compute-widths parent)
+ (undo-tree-move-to-parent node)
+ (setf (undo-tree-node-marker parent) (make-marker))
+ (set-marker-insertion-type
+ (undo-tree-node-marker parent) nil)
+ (move-marker (undo-tree-node-marker parent) (point))
+ ;; draw subtree beneath parent
+ (setq undo-tree-visualizer-needs-extending-down
+ (nconc (delq node (undo-tree-draw-subtree parent))
+ undo-tree-visualizer-needs-extending-down))
+ (setq extended t))
+ ;; ...otherwise, postpone drawing for later and exit
+ (setq undo-tree-visualizer-needs-extending-up (when parent node)
+ parent nil))
+
+ ;; if we've reached root, stop extending and add top margin
+ (setq undo-tree-visualizer-needs-extending-up nil)
+ (goto-char (undo-tree-node-marker node))
+ (undo-tree-move-up 1) ; top margin
+ (delete-region (point-min) (line-beginning-position)))
+ ;; next iteration
+ (setq node parent)))
+ extended))
+
+
+(defun undo-tree-expand-down (from &optional to)
+ ;; Expand tree downwards. FROM is the node to start expanding from. Stop
+ ;; expanding at TO if specified. Otherwise, just expand visible portion of
+ ;; tree and highlight active branch from FROM.
+ (when undo-tree-visualizer-needs-extending-down
+ (let ((inhibit-read-only t)
+ node-list extended)
+ ;; extend down as far as TO node
+ (when to
+ (setq extended (undo-tree-extend-down from to))
+ (goto-char (undo-tree-node-marker to))
+ (redisplay t)) ; force redisplay to scroll buffer if necessary
+ ;; extend visible portion of tree downwards
+ (setq node-list undo-tree-visualizer-needs-extending-down
+ undo-tree-visualizer-needs-extending-down nil)
+ (when node-list
+ (dolist (n node-list)
+ (when (undo-tree-extend-down n) (setq extended t)))
+ ;; highlight active branch in newly-extended-down portion, if any
+ (when extended
+ (let ((undo-tree-insert-face
+ 'undo-tree-visualizer-active-branch-face))
+ (undo-tree-highlight-active-branch from)))))))
+
+
+(defun undo-tree-expand-up (from &optional to)
+ ;; Expand tree upwards. FROM is the node to start expanding from, TO is the
+ ;; node to stop expanding at. If TO node isn't specified, just expand visible
+ ;; portion of tree and highlight active branch down to FROM.
+ (when undo-tree-visualizer-needs-extending-up
+ (let ((inhibit-read-only t)
+ extended node-list)
+ ;; extend up as far as TO node
+ (when to
+ (setq extended (undo-tree-extend-up from to))
+ (goto-char (undo-tree-node-marker to))
+ ;; simulate auto-scrolling if close to top of buffer
+ (when (<= (line-number-at-pos (point)) scroll-margin)
+ (undo-tree-move-up (if (= scroll-conservatively 0)
+ (/ (window-height) 2) 3))
+ (when (undo-tree-extend-up to) (setq extended t))
+ (goto-char (undo-tree-node-marker to))
+ (unless (= scroll-conservatively 0) (recenter scroll-margin))))
+ ;; extend visible portion of tree upwards
+ (and undo-tree-visualizer-needs-extending-up
+ (undo-tree-extend-up undo-tree-visualizer-needs-extending-up)
+ (setq extended t))
+ ;; extend visible portion of tree downwards
+ (setq node-list undo-tree-visualizer-needs-extending-down
+ undo-tree-visualizer-needs-extending-down nil)
+ (dolist (n node-list) (undo-tree-extend-down n))
+ ;; highlight active branch in newly-extended-up portion, if any
+ (when extended
+ (let ((undo-tree-insert-face
+ 'undo-tree-visualizer-active-branch-face))
+ (undo-tree-highlight-active-branch
+ (or undo-tree-visualizer-needs-extending-up
+ (undo-tree-root buffer-undo-tree))
+ from))))))
+
+
+
+(defun undo-tree-highlight-active-branch (node &optional end)
+ ;; Draw highlighted active branch below NODE in current buffer. Stop
+ ;; highlighting at END node if specified.
+ (let ((stack (list node)))
+ ;; draw active branch
+ (while stack
+ (setq node (pop stack))
+ (unless (or (eq node end)
+ (memq node undo-tree-visualizer-needs-extending-down))
+ (goto-char (undo-tree-node-marker node))
+ (setq node (undo-tree-draw-subtree node 'active)
+ stack (nconc stack node))))))
+
+
+(defun undo-tree-draw-node (node &optional current)
+ ;; Draw symbol representing NODE in visualizer. If CURRENT is non-nil, node
+ ;; is current node.
+ (goto-char (undo-tree-node-marker node))
+ (when undo-tree-visualizer-timestamps
+ (undo-tree-move-backward (/ undo-tree-visualizer-spacing 2)))
+
+ (let* ((undo-tree-insert-face (and undo-tree-insert-face
+ (or (and (consp undo-tree-insert-face)
+ undo-tree-insert-face)
+ (list undo-tree-insert-face))))
+ (register (undo-tree-node-register node))
+ (unmodified (if undo-tree-visualizer-parent-mtime
+ (undo-tree-node-unmodified-p
+ node undo-tree-visualizer-parent-mtime)
+ (undo-tree-node-unmodified-p node)))
+ node-string)
+ ;; check node's register (if any) still stores appropriate undo-tree state
+ (unless (and register
+ (undo-tree-register-data-p
+ (registerv-data (get-register register)))
+ (eq node (undo-tree-register-data-node
+ (registerv-data (get-register register)))))
+ (setq register nil))
+ ;; represent node by different symbols, depending on whether it's the
+ ;; current node, is saved in a register, or corresponds to an unmodified
+ ;; buffer
+ (setq node-string
+ (cond
+ (undo-tree-visualizer-timestamps
+ (undo-tree-timestamp-to-string
+ (undo-tree-node-timestamp node)
+ undo-tree-visualizer-relative-timestamps
+ current register))
+ (register (char-to-string register))
+ (unmodified "s")
+ (current "x")
+ (t "o"))
+ undo-tree-insert-face
+ (nconc
+ (cond
+ (current '(undo-tree-visualizer-current-face))
+ (unmodified '(undo-tree-visualizer-unmodified-face))
+ (register '(undo-tree-visualizer-register-face)))
+ undo-tree-insert-face))
+ ;; draw node and link it to its representation in visualizer
+ (undo-tree-insert node-string)
+ (undo-tree-move-backward (if undo-tree-visualizer-timestamps
+ (1+ (/ undo-tree-visualizer-spacing 2))
+ 1))
+ (move-marker (undo-tree-node-marker node) (point))
+ (put-text-property (point) (1+ (point)) 'undo-tree-node node)))
+
+
+(defun undo-tree-draw-subtree (node &optional active-branch)
+ ;; Draw subtree rooted at NODE. The subtree will start from point.
+ ;; If ACTIVE-BRANCH is non-nil, just draw active branch below NODE. Returns
+ ;; list of nodes below NODE.
+ (let ((num-children (length (undo-tree-node-next node)))
+ node-list pos trunk-pos n)
+ ;; draw node itself
+ (undo-tree-draw-node node)
+
+ (cond
+ ;; if we're at a leaf node, we're done
+ ((= num-children 0))
+
+ ;; if node has only one child, draw it (not strictly necessary to deal
+ ;; with this case separately, but as it's by far the most common case
+ ;; this makes the code clearer and more efficient)
+ ((= num-children 1)
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?|)
+ (undo-tree-move-backward 1)
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?|)
+ (undo-tree-move-backward 1)
+ (undo-tree-move-down 1)
+ (setq n (car (undo-tree-node-next node)))
+ ;; link next node to its representation in visualizer
+ (unless (markerp (undo-tree-node-marker n))
+ (setf (undo-tree-node-marker n) (make-marker))
+ (set-marker-insertion-type (undo-tree-node-marker n) nil))
+ (move-marker (undo-tree-node-marker n) (point))
+ ;; add next node to list of nodes to draw next
+ (push n node-list))
+
+ ;; if node has multiple children, draw branches
+ (t
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?|)
+ (undo-tree-move-backward 1)
+ (move-marker (setq trunk-pos (make-marker)) (point))
+ ;; left subtrees
+ (undo-tree-move-backward
+ (- (undo-tree-node-char-lwidth node)
+ (undo-tree-node-char-lwidth
+ (car (undo-tree-node-next node)))))
+ (move-marker (setq pos (make-marker)) (point))
+ (setq n (cons nil (undo-tree-node-next node)))
+ (dotimes (i (/ num-children 2))
+ (setq n (cdr n))
+ (when (or (null active-branch)
+ (eq (car n)
+ (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node))))
+ (undo-tree-move-forward 2)
+ (undo-tree-insert ?_ (- trunk-pos pos 2))
+ (goto-char pos)
+ (undo-tree-move-forward 1)
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?/)
+ (undo-tree-move-backward 2)
+ (undo-tree-move-down 1)
+ ;; link node to its representation in visualizer
+ (unless (markerp (undo-tree-node-marker (car n)))
+ (setf (undo-tree-node-marker (car n)) (make-marker))
+ (set-marker-insertion-type (undo-tree-node-marker (car n)) nil))
+ (move-marker (undo-tree-node-marker (car n)) (point))
+ ;; add node to list of nodes to draw next
+ (push (car n) node-list))
+ (goto-char pos)
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-rwidth (car n))
+ (undo-tree-node-char-lwidth (cadr n))
+ undo-tree-visualizer-spacing 1))
+ (move-marker pos (point)))
+ ;; middle subtree (only when number of children is odd)
+ (when (= (mod num-children 2) 1)
+ (setq n (cdr n))
+ (when (or (null active-branch)
+ (eq (car n)
+ (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node))))
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?|)
+ (undo-tree-move-backward 1)
+ (undo-tree-move-down 1)
+ ;; link node to its representation in visualizer
+ (unless (markerp (undo-tree-node-marker (car n)))
+ (setf (undo-tree-node-marker (car n)) (make-marker))
+ (set-marker-insertion-type (undo-tree-node-marker (car n)) nil))
+ (move-marker (undo-tree-node-marker (car n)) (point))
+ ;; add node to list of nodes to draw next
+ (push (car n) node-list))
+ (goto-char pos)
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-rwidth (car n))
+ (if (cadr n) (undo-tree-node-char-lwidth (cadr n)) 0)
+ undo-tree-visualizer-spacing 1))
+ (move-marker pos (point)))
+ ;; right subtrees
+ (move-marker trunk-pos (1+ trunk-pos))
+ (dotimes (i (/ num-children 2))
+ (setq n (cdr n))
+ (when (or (null active-branch)
+ (eq (car n)
+ (nth (undo-tree-node-branch node)
+ (undo-tree-node-next node))))
+ (goto-char trunk-pos)
+ (undo-tree-insert ?_ (- pos trunk-pos 1))
+ (goto-char pos)
+ (undo-tree-move-backward 1)
+ (undo-tree-move-down 1)
+ (undo-tree-insert ?\\)
+ (undo-tree-move-down 1)
+ ;; link node to its representation in visualizer
+ (unless (markerp (undo-tree-node-marker (car n)))
+ (setf (undo-tree-node-marker (car n)) (make-marker))
+ (set-marker-insertion-type (undo-tree-node-marker (car n)) nil))
+ (move-marker (undo-tree-node-marker (car n)) (point))
+ ;; add node to list of nodes to draw next
+ (push (car n) node-list))
+ (when (cdr n)
+ (goto-char pos)
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-rwidth (car n))
+ (if (cadr n) (undo-tree-node-char-lwidth (cadr n)) 0)
+ undo-tree-visualizer-spacing 1))
+ (move-marker pos (point))))
+ ))
+ ;; return list of nodes to draw next
+ (nreverse node-list)))
+
+
+(defun undo-tree-node-char-lwidth (node)
+ ;; Return left-width of NODE measured in characters.
+ (if (= (length (undo-tree-node-next node)) 0) 0
+ (- (* (+ undo-tree-visualizer-spacing 1) (undo-tree-node-lwidth node))
+ (if (= (undo-tree-node-cwidth node) 0)
+ (1+ (/ undo-tree-visualizer-spacing 2)) 0))))
+
+
+(defun undo-tree-node-char-rwidth (node)
+ ;; Return right-width of NODE measured in characters.
+ (if (= (length (undo-tree-node-next node)) 0) 0
+ (- (* (+ undo-tree-visualizer-spacing 1) (undo-tree-node-rwidth node))
+ (if (= (undo-tree-node-cwidth node) 0)
+ (1+ (/ undo-tree-visualizer-spacing 2)) 0))))
+
+
+(defun undo-tree-insert (str &optional arg)
+ ;; Insert character or string STR ARG times, overwriting, and using
+ ;; `undo-tree-insert-face'.
+ (unless arg (setq arg 1))
+ (when (characterp str)
+ (setq str (make-string arg str))
+ (setq arg 1))
+ (dotimes (i arg) (insert str))
+ (setq arg (* arg (length str)))
+ (undo-tree-move-forward arg)
+ ;; make sure mark isn't active, otherwise `backward-delete-char' might
+ ;; delete region instead of single char if transient-mark-mode is enabled
+ (setq mark-active nil)
+ (backward-delete-char arg)
+ (when undo-tree-insert-face
+ (put-text-property (- (point) arg) (point) 'face undo-tree-insert-face)))
+
+
+(defun undo-tree-move-down (&optional arg)
+ ;; Move down, extending buffer if necessary.
+ (let ((row (line-number-at-pos))
+ (col (current-column))
+ line)
+ (unless arg (setq arg 1))
+ (forward-line arg)
+ (setq line (line-number-at-pos))
+ ;; if buffer doesn't have enough lines, add some
+ (when (/= line (+ row arg))
+ (cond
+ ((< arg 0)
+ (insert (make-string (- line row arg) ?\n))
+ (forward-line (+ arg (- row line))))
+ (t (insert (make-string (- arg (- line row)) ?\n)))))
+ (undo-tree-move-forward col)))
+
+
+(defun undo-tree-move-up (&optional arg)
+ ;; Move up, extending buffer if necessary.
+ (unless arg (setq arg 1))
+ (undo-tree-move-down (- arg)))
+
+
+(defun undo-tree-move-forward (&optional arg)
+ ;; Move forward, extending buffer if necessary.
+ (unless arg (setq arg 1))
+ (let (n)
+ (cond
+ ((>= arg 0)
+ (setq n (- (line-end-position) (point)))
+ (if (> n arg)
+ (forward-char arg)
+ (end-of-line)
+ (insert (make-string (- arg n) ? ))))
+ ((< arg 0)
+ (setq arg (- arg))
+ (setq n (- (point) (line-beginning-position)))
+ (when (< (- n 2) arg) ; -2 to create left-margin
+ ;; no space left - shift entire buffer contents right!
+ (let ((pos (move-marker (make-marker) (point))))
+ (set-marker-insertion-type pos t)
+ (goto-char (point-min))
+ (while (not (eobp))
+ (insert-before-markers (make-string (- arg -2 n) ? ))
+ (forward-line 1))
+ (goto-char pos)))
+ (backward-char arg)))))
+
+
+(defun undo-tree-move-backward (&optional arg)
+ ;; Move backward, extending buffer if necessary.
+ (unless arg (setq arg 1))
+ (undo-tree-move-forward (- arg)))
+
+
+(defun undo-tree-move-to-parent (node)
+ ;; Move to position of parent of NODE, extending buffer if necessary.
+ (let* ((parent (undo-tree-node-previous node))
+ (n (undo-tree-node-next parent))
+ (l (length n)) p)
+ (goto-char (undo-tree-node-marker node))
+ (unless (= l 1)
+ ;; move horizontally
+ (setq p (undo-tree-position node n))
+ (cond
+ ;; node in centre subtree: no horizontal movement
+ ((and (= (mod l 2) 1) (= p (/ l 2))))
+ ;; node in left subtree: move right
+ ((< p (/ l 2))
+ (setq n (nthcdr p n))
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-rwidth (car n))
+ (/ undo-tree-visualizer-spacing 2) 1))
+ (dotimes (i (- (/ l 2) p 1))
+ (setq n (cdr n))
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-lwidth (car n))
+ (undo-tree-node-char-rwidth (car n))
+ undo-tree-visualizer-spacing 1)))
+ (when (= (mod l 2) 1)
+ (setq n (cdr n))
+ (undo-tree-move-forward
+ (+ (undo-tree-node-char-lwidth (car n))
+ (/ undo-tree-visualizer-spacing 2) 1))))
+ (t ;; node in right subtree: move left
+ (setq n (nthcdr (/ l 2) n))
+ (when (= (mod l 2) 1)
+ (undo-tree-move-backward
+ (+ (undo-tree-node-char-rwidth (car n))
+ (/ undo-tree-visualizer-spacing 2) 1))
+ (setq n (cdr n)))
+ (dotimes (i (- p (/ l 2) (mod l 2)))
+ (undo-tree-move-backward
+ (+ (undo-tree-node-char-lwidth (car n))
+ (undo-tree-node-char-rwidth (car n))
+ undo-tree-visualizer-spacing 1))
+ (setq n (cdr n)))
+ (undo-tree-move-backward
+ (+ (undo-tree-node-char-lwidth (car n))
+ (/ undo-tree-visualizer-spacing 2) 1)))))
+ ;; move vertically
+ (undo-tree-move-up 3)))
+
+
+(defun undo-tree-timestamp-to-string
+ (timestamp &optional relative current register)
+ ;; Convert TIMESTAMP to string (either absolute or RELATVE time), indicating
+ ;; if it's the CURRENT node and/or has an associated REGISTER.
+ (if relative
+ ;; relative time
+ (let ((time (floor (float-time
+ (subtract-time (current-time) timestamp))))
+ n)
+ (setq time
+ ;; years
+ (if (> (setq n (/ time 315360000)) 0)
+ (if (> n 999) "-ages" (format "-%dy" n))
+ (setq time (% time 315360000))
+ ;; days
+ (if (> (setq n (/ time 86400)) 0)
+ (format "-%dd" n)
+ (setq time (% time 86400))
+ ;; hours
+ (if (> (setq n (/ time 3600)) 0)
+ (format "-%dh" n)
+ (setq time (% time 3600))
+ ;; mins
+ (if (> (setq n (/ time 60)) 0)
+ (format "-%dm" n)
+ ;; secs
+ (format "-%ds" (% time 60)))))))
+ (setq time (concat
+ (if current "*" " ")
+ time
+ (if register (concat "[" (char-to-string register) "]")
+ " ")))
+ (setq n (length time))
+ (if (< n 9)
+ (concat (make-string (- 9 n) ? ) time)
+ time))
+ ;; absolute time
+ (concat (if current " *" " ")
+ (format-time-string "%H:%M:%S" timestamp)
+ (if register
+ (concat "[" (char-to-string register) "]")
+ " "))))
+
+
+
+\f
+;;; =====================================================================
+;;; Visualizer commands
+
+(define-derived-mode
+ undo-tree-visualizer-mode special-mode "undo-tree-visualizer"
+ "Major mode used in undo-tree visualizer.
+
+The undo-tree visualizer can only be invoked from a buffer in
+which `undo-tree-mode' is enabled. The visualizer displays the
+undo history tree graphically, and allows you to browse around
+the undo history, undoing or redoing the corresponding changes in
+the parent buffer.
+
+Within the undo-tree visualizer, the following keys are available:
+
+ \\{undo-tree-visualizer-mode-map}"
+ :syntax-table nil
+ :abbrev-table nil
+ (setq truncate-lines t)
+ (setq cursor-type nil)
+ (setq undo-tree-visualizer-selected-node nil))
+
+
+
+(defun undo-tree-visualize-undo (&optional arg)
+ "Undo changes. A numeric ARG serves as a repeat count."
+ (interactive "p")
+ (let ((old (undo-tree-current buffer-undo-tree))
+ current)
+ ;; unhighlight old current node
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-active-branch-face)
+ (inhibit-read-only t))
+ (undo-tree-draw-node old))
+ ;; undo in parent buffer
+ (switch-to-buffer-other-window undo-tree-visualizer-parent-buffer)
+ (deactivate-mark)
+ (unwind-protect
+ (let ((undo-tree-inhibit-kill-visualizer t)) (undo-tree-undo-1 arg))
+ (setq current (undo-tree-current buffer-undo-tree))
+ (switch-to-buffer-other-window undo-tree-visualizer-buffer-name)
+ ;; when using lazy drawing, extend tree upwards as required
+ (when undo-tree-visualizer-lazy-drawing
+ (undo-tree-expand-up old current))
+ ;; highlight new current node
+ (let ((inhibit-read-only t)) (undo-tree-draw-node current 'current))
+ ;; update diff display, if any
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-update-diff)))))
+
+
+(defun undo-tree-visualize-redo (&optional arg)
+ "Redo changes. A numeric ARG serves as a repeat count."
+ (interactive "p")
+ (let ((old (undo-tree-current buffer-undo-tree))
+ current)
+ ;; unhighlight old current node
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-active-branch-face)
+ (inhibit-read-only t))
+ (undo-tree-draw-node (undo-tree-current buffer-undo-tree)))
+ ;; redo in parent buffer
+ (switch-to-buffer-other-window undo-tree-visualizer-parent-buffer)
+ (deactivate-mark)
+ (unwind-protect
+ (let ((undo-tree-inhibit-kill-visualizer t)) (undo-tree-redo-1 arg))
+ (setq current (undo-tree-current buffer-undo-tree))
+ (switch-to-buffer-other-window undo-tree-visualizer-buffer-name)
+ ;; when using lazy drawing, extend tree downwards as required
+ (when undo-tree-visualizer-lazy-drawing
+ (undo-tree-expand-down old current))
+ ;; highlight new current node
+ (let ((inhibit-read-only t)) (undo-tree-draw-node current 'current))
+ ;; update diff display, if any
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-update-diff)))))
+
+
+(defun undo-tree-visualize-switch-branch-right (arg)
+ "Switch to next branch of the undo tree.
+This will affect which branch to descend when *redoing* changes
+using `undo-tree-redo' or `undo-tree-visualizer-redo'."
+ (interactive "p")
+ ;; un-highlight old active branch below current node
+ (goto-char (undo-tree-node-marker (undo-tree-current buffer-undo-tree)))
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-default-face)
+ (inhibit-read-only t))
+ (undo-tree-highlight-active-branch (undo-tree-current buffer-undo-tree)))
+ ;; increment branch
+ (let ((branch (undo-tree-node-branch (undo-tree-current buffer-undo-tree))))
+ (setf (undo-tree-node-branch (undo-tree-current buffer-undo-tree))
+ (cond
+ ((>= (+ branch arg) (undo-tree-num-branches))
+ (1- (undo-tree-num-branches)))
+ ((<= (+ branch arg) 0) 0)
+ (t (+ branch arg))))
+ (let ((inhibit-read-only t))
+ ;; highlight new active branch below current node
+ (goto-char (undo-tree-node-marker (undo-tree-current buffer-undo-tree)))
+ (let ((undo-tree-insert-face 'undo-tree-visualizer-active-branch-face))
+ (undo-tree-highlight-active-branch (undo-tree-current buffer-undo-tree)))
+ ;; re-highlight current node
+ (undo-tree-draw-node (undo-tree-current buffer-undo-tree) 'current))))
+
+
+(defun undo-tree-visualize-switch-branch-left (arg)
+ "Switch to previous branch of the undo tree.
+This will affect which branch to descend when *redoing* changes
+using `undo-tree-redo' or `undo-tree-visualizer-redo'."
+ (interactive "p")
+ (undo-tree-visualize-switch-branch-right (- arg)))
+
+
+(defun undo-tree-visualizer-quit ()
+ "Quit the undo-tree visualizer."
+ (interactive)
+ (undo-tree-clear-visualizer-data buffer-undo-tree)
+ ;; remove kill visualizer hook from parent buffer
+ (unwind-protect
+ (with-current-buffer undo-tree-visualizer-parent-buffer
+ (remove-hook 'before-change-functions 'undo-tree-kill-visualizer t))
+ ;; kill diff buffer, if any
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-hide-diff))
+ (let ((parent undo-tree-visualizer-parent-buffer)
+ window)
+ ;; kill visualizer buffer
+ (kill-buffer nil)
+ ;; switch back to parent buffer
+ (unwind-protect
+ (if (setq window (get-buffer-window parent))
+ (select-window window)
+ (switch-to-buffer parent))))))
+
+
+(defun undo-tree-visualizer-abort ()
+ "Quit the undo-tree visualizer and return buffer to original state."
+ (interactive)
+ (let ((node undo-tree-visualizer-initial-node))
+ (undo-tree-visualizer-quit)
+ (undo-tree-set node)))
+
+
+(defun undo-tree-visualizer-set (&optional pos)
+ "Set buffer to state corresponding to undo tree node
+at POS, or point if POS is nil."
+ (interactive)
+ (unless pos (setq pos (point)))
+ (let ((node (get-text-property pos 'undo-tree-node)))
+ (when node
+ ;; set parent buffer to state corresponding to node at POS
+ (switch-to-buffer-other-window undo-tree-visualizer-parent-buffer)
+ (let ((undo-tree-inhibit-kill-visualizer t)) (undo-tree-set node))
+ (switch-to-buffer-other-window undo-tree-visualizer-buffer-name)
+ ;; re-draw undo tree
+ (let ((inhibit-read-only t)) (undo-tree-draw-tree buffer-undo-tree))
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-update-diff)))))
+
+
+(defun undo-tree-visualizer-mouse-set (pos)
+ "Set buffer to state corresponding to undo tree node
+at mouse event POS."
+ (interactive "@e")
+ (undo-tree-visualizer-set (event-start (nth 1 pos))))
+
+
+(defun undo-tree-visualize-undo-to-x (&optional x)
+ "Undo to last branch point, register, or saved state.
+If X is the symbol `branch', undo to last branch point. If X is
+the symbol `register', undo to last register. If X is the sumbol
+`saved', undo to last saved state. If X is null, undo to first of
+these that's encountered.
+
+Interactively, a single \\[universal-argument] specifies
+`branch', a double \\[universal-argument] \\[universal-argument]
+specifies `saved', and a negative prefix argument specifies
+`register'."
+ (interactive "P")
+ (when (and (called-interactively-p 'any) x)
+ (setq x (prefix-numeric-value x)
+ x (cond
+ ((< x 0) 'register)
+ ((<= x 4) 'branch)
+ (t 'saved))))
+ (let ((current (if undo-tree-visualizer-selection-mode
+ undo-tree-visualizer-selected-node
+ (undo-tree-current buffer-undo-tree)))
+ (diff undo-tree-visualizer-diff)
+ r)
+ (undo-tree-visualizer-hide-diff)
+ (while (and (undo-tree-node-previous current)
+ (or (if undo-tree-visualizer-selection-mode
+ (progn
+ (undo-tree-visualizer-select-previous)
+ (setq current undo-tree-visualizer-selected-node))
+ (undo-tree-visualize-undo)
+ (setq current (undo-tree-current buffer-undo-tree)))
+ t)
+ ;; branch point
+ (not (or (and (or (null x) (eq x 'branch))
+ (> (undo-tree-num-branches) 1))
+ ;; register
+ (and (or (null x) (eq x 'register))
+ (setq r (undo-tree-node-register current))
+ (undo-tree-register-data-p
+ (setq r (registerv-data (get-register r))))
+ (eq current (undo-tree-register-data-node r)))
+ ;; saved state
+ (and (or (null x) (eq x 'saved))
+ (undo-tree-node-unmodified-p current))
+ ))))
+ ;; update diff display, if any
+ (when diff
+ (undo-tree-visualizer-show-diff
+ (when undo-tree-visualizer-selection-mode
+ undo-tree-visualizer-selected-node)))))
+
+
+(defun undo-tree-visualize-redo-to-x (&optional x)
+ "Redo to last branch point, register, or saved state.
+If X is the symbol `branch', redo to last branch point. If X is
+the symbol `register', redo to last register. If X is the sumbol
+`saved', redo to last saved state. If X is null, redo to first of
+these that's encountered.
+
+Interactively, a single \\[universal-argument] specifies
+`branch', a double \\[universal-argument] \\[universal-argument]
+specifies `saved', and a negative prefix argument specifies
+`register'."
+ (interactive "P")
+ (when (and (called-interactively-p 'any) x)
+ (setq x (prefix-numeric-value x)
+ x (cond
+ ((< x 0) 'register)
+ ((<= x 4) 'branch)
+ (t 'saved))))
+ (let ((current (if undo-tree-visualizer-selection-mode
+ undo-tree-visualizer-selected-node
+ (undo-tree-current buffer-undo-tree)))
+ (diff undo-tree-visualizer-diff)
+ r)
+ (undo-tree-visualizer-hide-diff)
+ (while (and (undo-tree-node-next current)
+ (or (if undo-tree-visualizer-selection-mode
+ (progn
+ (undo-tree-visualizer-select-next)
+ (setq current undo-tree-visualizer-selected-node))
+ (undo-tree-visualize-redo)
+ (setq current (undo-tree-current buffer-undo-tree)))
+ t)
+ ;; branch point
+ (not (or (and (or (null x) (eq x 'branch))
+ (> (undo-tree-num-branches) 1))
+ ;; register
+ (and (or (null x) (eq x 'register))
+ (setq r (undo-tree-node-register current))
+ (undo-tree-register-data-p
+ (setq r (registerv-data (get-register r))))
+ (eq current (undo-tree-register-data-node r)))
+ ;; saved state
+ (and (or (null x) (eq x 'saved))
+ (undo-tree-node-unmodified-p current))
+ ))))
+ ;; update diff display, if any
+ (when diff
+ (undo-tree-visualizer-show-diff
+ (when undo-tree-visualizer-selection-mode
+ undo-tree-visualizer-selected-node)))))
+
+
+(defun undo-tree-visualizer-toggle-timestamps ()
+ "Toggle display of time-stamps."
+ (interactive)
+ (setq undo-tree-visualizer-timestamps (not undo-tree-visualizer-timestamps))
+ (setq undo-tree-visualizer-spacing (undo-tree-visualizer-calculate-spacing))
+ ;; redraw tree
+ (let ((inhibit-read-only t)) (undo-tree-draw-tree buffer-undo-tree)))
+
+
+(defun undo-tree-visualizer-scroll-left (&optional arg)
+ (interactive "p")
+ (scroll-left (or arg 1) t))
+
+
+(defun undo-tree-visualizer-scroll-right (&optional arg)
+ (interactive "p")
+ (scroll-right (or arg 1) t))
+
+
+(defun undo-tree-visualizer-scroll-up (&optional arg)
+ (interactive "P")
+ (if (or (and (numberp arg) (< arg 0)) (eq arg '-))
+ (undo-tree-visualizer-scroll-down arg)
+ ;; scroll up and expand newly-visible portion of tree
+ (unwind-protect
+ (scroll-up-command arg)
+ (undo-tree-expand-down
+ (nth (undo-tree-node-branch (undo-tree-current buffer-undo-tree))
+ (undo-tree-node-next (undo-tree-current buffer-undo-tree)))))
+ ;; signal error if at eob
+ (when (and (not undo-tree-visualizer-needs-extending-down) (eobp))
+ (scroll-up))))
+
+
+(defun undo-tree-visualizer-scroll-down (&optional arg)
+ (interactive "P")
+ (if (or (and (numberp arg) (< arg 0)) (eq arg '-))
+ (undo-tree-visualizer-scroll-up arg)
+ ;; ensure there's enough room at top of buffer to scroll
+ (let ((scroll-lines
+ (or arg (- (window-height) next-screen-context-lines)))
+ (window-line (1- (line-number-at-pos (window-start)))))
+ (when (and undo-tree-visualizer-needs-extending-up
+ (< window-line scroll-lines))
+ (let ((inhibit-read-only t))
+ (goto-char (point-min))
+ (undo-tree-move-up (- scroll-lines window-line)))))
+ ;; scroll down and expand newly-visible portion of tree
+ (unwind-protect
+ (scroll-down-command arg)
+ (undo-tree-expand-up
+ (undo-tree-node-previous (undo-tree-current buffer-undo-tree))))
+ ;; signal error if at bob
+ (when (and (not undo-tree-visualizer-needs-extending-down) (bobp))
+ (scroll-down))))
+
+
+
+\f
+;;; =====================================================================
+;;; Visualizer selection mode
+
+(define-minor-mode undo-tree-visualizer-selection-mode
+ "Toggle mode to select nodes in undo-tree visualizer."
+ :lighter "Select"
+ :keymap undo-tree-visualizer-selection-mode-map
+ :group undo-tree
+ (cond
+ ;; enable selection mode
+ (undo-tree-visualizer-selection-mode
+ (setq cursor-type 'box)
+ (setq undo-tree-visualizer-selected-node
+ (undo-tree-current buffer-undo-tree))
+ ;; erase diff (if any), as initially selected node is identical to current
+ (when undo-tree-visualizer-diff
+ (let ((buff (get-buffer undo-tree-diff-buffer-name))
+ (inhibit-read-only t))
+ (when buff (with-current-buffer buff (erase-buffer))))))
+ (t ;; disable selection mode
+ (setq cursor-type nil)
+ (setq undo-tree-visualizer-selected-node nil)
+ (goto-char (undo-tree-node-marker (undo-tree-current buffer-undo-tree)))
+ (when undo-tree-visualizer-diff (undo-tree-visualizer-update-diff)))
+ ))
+
+
+(defun undo-tree-visualizer-select-previous (&optional arg)
+ "Move to previous node."
+ (interactive "p")
+ (let ((node undo-tree-visualizer-selected-node))
+ (catch 'top
+ (dotimes (i (or arg 1))
+ (unless (undo-tree-node-previous node) (throw 'top t))
+ (setq node (undo-tree-node-previous node))))
+ ;; when using lazy drawing, extend tree upwards as required
+ (when undo-tree-visualizer-lazy-drawing
+ (undo-tree-expand-up undo-tree-visualizer-selected-node node))
+ ;; update diff display, if any
+ (when (and undo-tree-visualizer-diff
+ (not (eq node undo-tree-visualizer-selected-node)))
+ (undo-tree-visualizer-update-diff node))
+ ;; move to selected node
+ (goto-char (undo-tree-node-marker node))
+ (setq undo-tree-visualizer-selected-node node)))
+
+
+(defun undo-tree-visualizer-select-next (&optional arg)
+ "Move to next node."
+ (interactive "p")
+ (let ((node undo-tree-visualizer-selected-node))
+ (catch 'bottom
+ (dotimes (i (or arg 1))
+ (unless (nth (undo-tree-node-branch node) (undo-tree-node-next node))
+ (throw 'bottom t))
+ (setq node
+ (nth (undo-tree-node-branch node) (undo-tree-node-next node)))))
+ ;; when using lazy drawing, extend tree downwards as required
+ (when undo-tree-visualizer-lazy-drawing
+ (undo-tree-expand-down undo-tree-visualizer-selected-node node))
+ ;; update diff display, if any
+ (when (and undo-tree-visualizer-diff
+ (not (eq node undo-tree-visualizer-selected-node)))
+ (undo-tree-visualizer-update-diff node))
+ ;; move to selected node
+ (goto-char (undo-tree-node-marker node))
+ (setq undo-tree-visualizer-selected-node node)))
+
+
+(defun undo-tree-visualizer-select-right (&optional arg)
+ "Move right to a sibling node."
+ (interactive "p")
+ (let ((node undo-tree-visualizer-selected-node)
+ end)
+ (goto-char (undo-tree-node-marker undo-tree-visualizer-selected-node))
+ (setq end (line-end-position))
+ (catch 'end
+ (dotimes (i arg)
+ (while (or (null node) (eq node undo-tree-visualizer-selected-node))
+ (forward-char)
+ (setq node (get-text-property (point) 'undo-tree-node))
+ (when (= (point) end) (throw 'end t)))))
+ (goto-char (undo-tree-node-marker
+ (or node undo-tree-visualizer-selected-node)))
+ (when (and undo-tree-visualizer-diff node
+ (not (eq node undo-tree-visualizer-selected-node)))
+ (undo-tree-visualizer-update-diff node))
+ (when node (setq undo-tree-visualizer-selected-node node))))
+
+
+(defun undo-tree-visualizer-select-left (&optional arg)
+ "Move left to a sibling node."
+ (interactive "p")
+ (let ((node (get-text-property (point) 'undo-tree-node))
+ beg)
+ (goto-char (undo-tree-node-marker undo-tree-visualizer-selected-node))
+ (setq beg (line-beginning-position))
+ (catch 'beg
+ (dotimes (i arg)
+ (while (or (null node) (eq node undo-tree-visualizer-selected-node))
+ (backward-char)
+ (setq node (get-text-property (point) 'undo-tree-node))
+ (when (= (point) beg) (throw 'beg t)))))
+ (goto-char (undo-tree-node-marker
+ (or node undo-tree-visualizer-selected-node)))
+ (when (and undo-tree-visualizer-diff node
+ (not (eq node undo-tree-visualizer-selected-node)))
+ (undo-tree-visualizer-update-diff node))
+ (when node (setq undo-tree-visualizer-selected-node node))))
+
+
+(defun undo-tree-visualizer-select (pos)
+ (let ((node (get-text-property pos 'undo-tree-node)))
+ (when node
+ ;; select node at POS
+ (goto-char (undo-tree-node-marker node))
+ ;; when using lazy drawing, extend tree up and down as required
+ (when undo-tree-visualizer-lazy-drawing
+ (undo-tree-expand-up undo-tree-visualizer-selected-node node)
+ (undo-tree-expand-down undo-tree-visualizer-selected-node node))
+ ;; update diff display, if any
+ (when (and undo-tree-visualizer-diff
+ (not (eq node undo-tree-visualizer-selected-node)))
+ (undo-tree-visualizer-update-diff node))
+ ;; update selected node
+ (setq undo-tree-visualizer-selected-node node)
+ )))
+
+
+(defun undo-tree-visualizer-mouse-select (pos)
+ "Select undo tree node at mouse event POS."
+ (interactive "@e")
+ (undo-tree-visualizer-select (event-start (nth 1 pos))))
+
+
+
+\f
+;;; =====================================================================
+;;; Visualizer diff display
+
+(defun undo-tree-visualizer-toggle-diff ()
+ "Toggle diff display in undo-tree visualizer."
+ (interactive)
+ (if undo-tree-visualizer-diff
+ (undo-tree-visualizer-hide-diff)
+ (undo-tree-visualizer-show-diff)))
+
+
+(defun undo-tree-visualizer-selection-toggle-diff ()
+ "Toggle diff display in undo-tree visualizer selection mode."
+ (interactive)
+ (if undo-tree-visualizer-diff
+ (undo-tree-visualizer-hide-diff)
+ (let ((node (get-text-property (point) 'undo-tree-node)))
+ (when node (undo-tree-visualizer-show-diff node)))))
+
+
+(defun undo-tree-visualizer-show-diff (&optional node)
+ ;; show visualizer diff display
+ (setq undo-tree-visualizer-diff t)
+ (let ((buff (with-current-buffer undo-tree-visualizer-parent-buffer
+ (undo-tree-diff node)))
+ (display-buffer-mark-dedicated 'soft)
+ win)
+ (setq win (split-window))
+ (set-window-buffer win buff)
+ (shrink-window-if-larger-than-buffer win)))
+
+
+(defun undo-tree-visualizer-hide-diff ()
+ ;; hide visualizer diff display
+ (setq undo-tree-visualizer-diff nil)
+ (let ((win (get-buffer-window undo-tree-diff-buffer-name)))
+ (when win (with-selected-window win (kill-buffer-and-window)))))
+
+
+(defun undo-tree-diff (&optional node)
+ ;; Create diff between NODE and current state (or previous state and current
+ ;; state, if NODE is null). Returns buffer containing diff.
+ (let (tmpfile buff)
+ ;; generate diff
+ (let ((undo-tree-inhibit-kill-visualizer t)
+ (current (undo-tree-current buffer-undo-tree)))
+ (undo-tree-set (or node (undo-tree-node-previous current) current)
+ 'preserve-timestamps)
+ (setq tmpfile (diff-file-local-copy (current-buffer)))
+ (undo-tree-set current 'preserve-timestamps))
+ (setq buff (diff-no-select
+ tmpfile (current-buffer) nil 'noasync
+ (get-buffer-create undo-tree-diff-buffer-name)))
+ ;; delete process messages and useless headers from diff buffer
+ (let ((inhibit-read-only t))
+ (with-current-buffer buff
+ (goto-char (point-min))
+ (delete-region (point) (1+ (line-end-position 3)))
+ (goto-char (point-max))
+ (forward-line -2)
+ (delete-region (point) (point-max))
+ (setq cursor-type nil)
+ (setq buffer-read-only t)))
+ buff))
+
+
+(defun undo-tree-visualizer-update-diff (&optional node)
+ ;; update visualizer diff display to show diff between current state and
+ ;; NODE (or previous state, if NODE is null)
+ (with-current-buffer undo-tree-visualizer-parent-buffer
+ (undo-tree-diff node))
+ (let ((win (get-buffer-window undo-tree-diff-buffer-name)))
+ (when win
+ (balance-windows)
+ (shrink-window-if-larger-than-buffer win))))
+
+
+
+(provide 'undo-tree)
+
+;;; undo-tree.el ends here
projects / emacsconfig.git / commitdiff