initial implementation

4 files changed, 155 insertions, 0 deletions

diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d59eb6e
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,19 @@
+Copyright 2018 Jesse Luehrs
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a9f881c
--- /dev/null
+++ b/README.md
@@ -0,0 +1,23 @@
+# Overview
+
+This plugin adds commands which diff the current buffer against the file it
+was loaded from, either the state on disk or the state in version control
+(similar to `vimdiff` except without requiring writing the buffer state to
+disk).
+
+# Commands
+
+## `:DiffAgainstFilesystem`
+
+Opens a diff window which diffs the buffer contents against the contents of
+the file on disk. Use |:DiffStop| to close the diff window.
+
+## `:DiffAgainstVCS`
+
+Opens a diff window which diffs the buffer contents against the contents of
+the file in the most recent commit in version control. Use |:DiffStop| to
+close the diff window. Supports git, svn, darcs, and cvs.
+
+## `:DiffStop`
+
+Closes an active diff window.
diff --git a/doc/diff-changes.txt b/doc/diff-changes.txt
new file mode 100644
index 0000000..0f56a0b
--- /dev/null
+++ b/doc/diff-changes.txt
@@ -0,0 +1,38 @@
+*diff-changes.txt*  Diff buffer contents against file on disk or in the VCS
+
+Author:  Jesse Luehrs <https://tozt.net/>
+License: MIT
+
+=============================================================================
+OVERVIEW                                              *diff-changes-overview*
+
+This plugin adds commands which diff the current buffer against the file it
+was loaded from, either the state on disk or the state in version control
+(similar to `vimdiff` except without requiring writing the buffer state to
+disk).
+
+=============================================================================
+COMMANDS                                              *diff-changes-commands*
+
+                                       *:DiffAgainstFilesystem*
+>
+    :DiffAgainstFilesystem
+<
+Opens a diff window which diffs the buffer contents against the contents of
+the file on disk. Use |:DiffStop| to close the diff window.
+
+                                       *:DiffAgainstVCS*
+>
+    :DiffAgainstVCS
+<
+Opens a diff window which diffs the buffer contents against the contents of
+the file in the most recent commit in version control. Use |:DiffStop| to
+close the diff window. Supports git, svn, darcs, and cvs.
+
+                                       *:DiffStop*
+>
+    :DiffStop
+<
+Closes an active diff window.
+
+ vim:tw=78:et:ft=help:norl:
diff --git a/plugin/diff-changes.vim b/plugin/diff-changes.vim
new file mode 100644
index 0000000..acd2cbd
--- /dev/null
+++ b/plugin/diff-changes.vim
@@ -0,0 +1,75 @@
+if exists('g:loaded_diff_changes') || &cp
+  finish
+endif
+let g:loaded_diff_changes = 1
+
+let s:foldmethod = &foldmethod
+let s:foldenable = &foldenable
+let s:diffwindow = 0
+
+function! s:diffstart(read_cmd)
+    if s:diffwindow != 0
+        return
+    endif
+    let s:foldmethod = &foldmethod
+    let s:foldenable = &foldenable
+    let l:filetype = &filetype
+    vert new
+    let s:diffwindow = winnr()
+    set buftype=nofile
+    try
+        exe a:read_cmd
+    catch /.*/
+        echohl ErrorMsg
+        echo v:exception
+        echohl NONE
+        call s:diffstop()
+        return
+    endtry
+    let &filetype = l:filetype
+    diffthis
+    wincmd p
+    diffthis
+endfunction
+
+function! s:diffstop()
+    if s:diffwindow == 0
+        return
+    endif
+    diffoff!
+    exe s:diffwindow . 'wincmd w'
+    bdelete
+    let &foldmethod = s:foldmethod
+    let &foldenable = s:foldenable
+    if &foldenable
+        if &foldmethod == 'marker'
+            normal! zv
+        else
+            normal! zE
+        end
+    endif
+    let s:diffwindow = 0
+endfunction
+
+function! s:vcs_orig(file)
+    " XXX: would be nice to use a:file rather than # here...
+    let l:dir = expand('#:p:h')
+    if filewritable(l:dir . '/.svn') == 2
+        return system('svn cat ' . a:file)
+    elseif filewritable(l:dir . '/CVS') == 2
+        return system("AFILE=" . a:file . "; MODFILE=`tempfile`; DIFF=`tempfile`; cp $AFILE $MODFILE && cvs diff -u $AFILE > $DIFF; patch -R $MODFILE $DIFF 2>&1 > /dev/null && cat $MODFILE; rm $MODFILE $DIFF")
+    elseif finddir('_darcs', l:dir . ';') =~# '_darcs'
+        return system('darcs show contents ' . a:file)
+    elseif finddir('.git', l:dir . ';') =~# '.git'
+        let l:prefix = system('git rev-parse --show-prefix')
+        let l:prefix = substitute(l:prefix, '\n', '', 'g')
+        let l:cmd = 'git show HEAD:'.l:prefix.a:file
+        return system(l:cmd)
+    else
+        throw 'No VCS directory found'
+    endif
+endfunction
+
+command DiffAgainstFilesystem call <SID>diffstart('read # | normal! ggdd')
+command DiffAgainstVCS call <SID>diffstart('call append(0, split(s:vcs_orig(expand("#:.")), "\n", 1)) | normal! Gdddd')
+command DiffStop call <SID>diffstop()