Merge branch 'lm/git-blame-el' into maint
[git] / git-gui / lib / diff.tcl
1 # git-gui diff viewer
2 # Copyright (C) 2006, 2007 Shawn Pearce
3
4 proc clear_diff {} {
5         global ui_diff current_diff_path current_diff_header
6         global ui_index ui_workdir
7
8         $ui_diff conf -state normal
9         $ui_diff delete 0.0 end
10         $ui_diff conf -state disabled
11
12         set current_diff_path {}
13         set current_diff_header {}
14
15         $ui_index tag remove in_diff 0.0 end
16         $ui_workdir tag remove in_diff 0.0 end
17 }
18
19 proc reshow_diff {{after {}}} {
20         global file_states file_lists
21         global current_diff_path current_diff_side
22         global ui_diff
23
24         set p $current_diff_path
25         if {$p eq {}} {
26                 # No diff is being shown.
27         } elseif {$current_diff_side eq {}} {
28                 clear_diff
29         } elseif {[catch {set s $file_states($p)}]
30                 || [lsearch -sorted -exact $file_lists($current_diff_side) $p] == -1} {
31
32                 if {[find_next_diff $current_diff_side $p {} {[^O]}]} {
33                         next_diff $after
34                 } else {
35                         clear_diff
36                 }
37         } else {
38                 set save_pos [lindex [$ui_diff yview] 0]
39                 show_diff $p $current_diff_side {} $save_pos $after
40         }
41 }
42
43 proc force_diff_encoding {enc} {
44         global current_diff_path
45         
46         if {$current_diff_path ne {}} {
47                 force_path_encoding $current_diff_path $enc
48                 reshow_diff
49         }
50 }
51
52 proc handle_empty_diff {} {
53         global current_diff_path file_states file_lists
54         global diff_empty_count
55
56         set path $current_diff_path
57         set s $file_states($path)
58         if {[lindex $s 0] ne {_M} || [has_textconv $path]} return
59
60         # Prevent infinite rescan loops
61         incr diff_empty_count
62         if {$diff_empty_count > 1} return
63
64         info_popup [mc "No differences detected.
65
66 %s has no changes.
67
68 The modification date of this file was updated by another application, but the content within the file was not changed.
69
70 A rescan will be automatically started to find other files which may have the same state." [short_path $path]]
71
72         clear_diff
73         display_file $path __
74         rescan ui_ready 0
75 }
76
77 proc show_diff {path w {lno {}} {scroll_pos {}} {callback {}}} {
78         global file_states file_lists
79         global is_3way_diff is_conflict_diff diff_active repo_config
80         global ui_diff ui_index ui_workdir
81         global current_diff_path current_diff_side current_diff_header
82         global current_diff_queue
83
84         if {$diff_active || ![lock_index read]} return
85
86         clear_diff
87         if {$lno == {}} {
88                 set lno [lsearch -sorted -exact $file_lists($w) $path]
89                 if {$lno >= 0} {
90                         incr lno
91                 }
92         }
93         if {$lno >= 1} {
94                 $w tag add in_diff $lno.0 [expr {$lno + 1}].0
95                 $w see $lno.0
96         }
97
98         set s $file_states($path)
99         set m [lindex $s 0]
100         set is_conflict_diff 0
101         set current_diff_path $path
102         set current_diff_side $w
103         set current_diff_queue {}
104         ui_status [mc "Loading diff of %s..." [escape_path $path]]
105
106         set cont_info [list $scroll_pos $callback]
107
108         if {[string first {U} $m] >= 0} {
109                 merge_load_stages $path [list show_unmerged_diff $cont_info]
110         } elseif {$m eq {_O}} {
111                 show_other_diff $path $w $m $cont_info
112         } else {
113                 start_show_diff $cont_info
114         }
115 }
116
117 proc show_unmerged_diff {cont_info} {
118         global current_diff_path current_diff_side
119         global merge_stages ui_diff is_conflict_diff
120         global current_diff_queue
121
122         if {$merge_stages(2) eq {}} {
123                 set is_conflict_diff 1
124                 lappend current_diff_queue \
125                         [list [mc "LOCAL: deleted\nREMOTE:\n"] d= \
126                             [list ":1:$current_diff_path" ":3:$current_diff_path"]]
127         } elseif {$merge_stages(3) eq {}} {
128                 set is_conflict_diff 1
129                 lappend current_diff_queue \
130                         [list [mc "REMOTE: deleted\nLOCAL:\n"] d= \
131                             [list ":1:$current_diff_path" ":2:$current_diff_path"]]
132         } elseif {[lindex $merge_stages(1) 0] eq {120000}
133                 || [lindex $merge_stages(2) 0] eq {120000}
134                 || [lindex $merge_stages(3) 0] eq {120000}} {
135                 set is_conflict_diff 1
136                 lappend current_diff_queue \
137                         [list [mc "LOCAL:\n"] d= \
138                             [list ":1:$current_diff_path" ":2:$current_diff_path"]]
139                 lappend current_diff_queue \
140                         [list [mc "REMOTE:\n"] d= \
141                             [list ":1:$current_diff_path" ":3:$current_diff_path"]]
142         } else {
143                 start_show_diff $cont_info
144                 return
145         }
146
147         advance_diff_queue $cont_info
148 }
149
150 proc advance_diff_queue {cont_info} {
151         global current_diff_queue ui_diff
152
153         set item [lindex $current_diff_queue 0]
154         set current_diff_queue [lrange $current_diff_queue 1 end]
155
156         $ui_diff conf -state normal
157         $ui_diff insert end [lindex $item 0] [lindex $item 1]
158         $ui_diff conf -state disabled
159
160         start_show_diff $cont_info [lindex $item 2]
161 }
162
163 proc show_other_diff {path w m cont_info} {
164         global file_states file_lists
165         global is_3way_diff diff_active repo_config
166         global ui_diff ui_index ui_workdir
167         global current_diff_path current_diff_side current_diff_header
168
169         # - Git won't give us the diff, there's nothing to compare to!
170         #
171         if {$m eq {_O}} {
172                 set max_sz 100000
173                 set type unknown
174                 if {[catch {
175                                 set type [file type $path]
176                                 switch -- $type {
177                                 directory {
178                                         set type submodule
179                                         set content {}
180                                         set sz 0
181                                 }
182                                 link {
183                                         set content [file readlink $path]
184                                         set sz [string length $content]
185                                 }
186                                 file {
187                                         set fd [open $path r]
188                                         fconfigure $fd \
189                                                 -eofchar {} \
190                                                 -encoding [get_path_encoding $path]
191                                         set content [read $fd $max_sz]
192                                         close $fd
193                                         set sz [file size $path]
194                                 }
195                                 default {
196                                         error "'$type' not supported"
197                                 }
198                                 }
199                         } err ]} {
200                         set diff_active 0
201                         unlock_index
202                         ui_status [mc "Unable to display %s" [escape_path $path]]
203                         error_popup [strcat [mc "Error loading file:"] "\n\n$err"]
204                         return
205                 }
206                 $ui_diff conf -state normal
207                 if {$type eq {submodule}} {
208                         $ui_diff insert end [append \
209                                 "* " \
210                                 [mc "Git Repository (subproject)"] \
211                                 "\n"] d_info
212                 } elseif {![catch {set type [exec file $path]}]} {
213                         set n [string length $path]
214                         if {[string equal -length $n $path $type]} {
215                                 set type [string range $type $n end]
216                                 regsub {^:?\s*} $type {} type
217                         }
218                         $ui_diff insert end "* $type\n" d_info
219                 }
220                 if {[string first "\0" $content] != -1} {
221                         $ui_diff insert end \
222                                 [mc "* Binary file (not showing content)."] \
223                                 d_info
224                 } else {
225                         if {$sz > $max_sz} {
226                                 $ui_diff insert end [mc \
227 "* Untracked file is %d bytes.
228 * Showing only first %d bytes.
229 " $sz $max_sz] d_info
230                         }
231                         $ui_diff insert end $content
232                         if {$sz > $max_sz} {
233                                 $ui_diff insert end [mc "
234 * Untracked file clipped here by %s.
235 * To see the entire file, use an external editor.
236 " [appname]] d_info
237                         }
238                 }
239                 $ui_diff conf -state disabled
240                 set diff_active 0
241                 unlock_index
242                 set scroll_pos [lindex $cont_info 0]
243                 if {$scroll_pos ne {}} {
244                         update
245                         $ui_diff yview moveto $scroll_pos
246                 }
247                 ui_ready
248                 set callback [lindex $cont_info 1]
249                 if {$callback ne {}} {
250                         eval $callback
251                 }
252                 return
253         }
254 }
255
256 proc get_conflict_marker_size {path} {
257         set size 7
258         catch {
259                 set fd_rc [eval [list git_read check-attr "conflict-marker-size" -- $path]]
260                 set ret [gets $fd_rc line]
261                 close $fd_rc
262                 if {$ret > 0} {
263                         regexp {.*: conflict-marker-size: (\d+)$} $line line size
264                 }
265         }
266         return $size
267 }
268
269 proc start_show_diff {cont_info {add_opts {}}} {
270         global file_states file_lists
271         global is_3way_diff is_submodule_diff diff_active repo_config
272         global ui_diff ui_index ui_workdir
273         global current_diff_path current_diff_side current_diff_header
274
275         set path $current_diff_path
276         set w $current_diff_side
277
278         set s $file_states($path)
279         set m [lindex $s 0]
280         set is_3way_diff 0
281         set is_submodule_diff 0
282         set diff_active 1
283         set current_diff_header {}
284         set conflict_size [get_conflict_marker_size $path]
285
286         set cmd [list]
287         if {$w eq $ui_index} {
288                 lappend cmd diff-index
289                 lappend cmd --cached
290         } elseif {$w eq $ui_workdir} {
291                 if {[string first {U} $m] >= 0} {
292                         lappend cmd diff
293                 } else {
294                         lappend cmd diff-files
295                 }
296         }
297         if {![is_config_false gui.textconv] && [git-version >= 1.6.1]} {
298                 lappend cmd --textconv
299         }
300
301         if {[string match {160000 *} [lindex $s 2]]
302          || [string match {160000 *} [lindex $s 3]]} {
303                 set is_submodule_diff 1
304
305                 if {[git-version >= "1.6.6"]} {
306                         lappend cmd --submodule
307                 }
308         }
309
310         lappend cmd -p
311         lappend cmd --color
312         set cmd [concat $cmd $repo_config(gui.diffopts)]
313         if {$repo_config(gui.diffcontext) >= 1} {
314                 lappend cmd "-U$repo_config(gui.diffcontext)"
315         }
316         if {$w eq $ui_index} {
317                 lappend cmd [PARENT]
318         }
319         if {$add_opts ne {}} {
320                 eval lappend cmd $add_opts
321         } else {
322                 lappend cmd --
323                 lappend cmd $path
324         }
325
326         if {$is_submodule_diff && [git-version < "1.6.6"]} {
327                 if {$w eq $ui_index} {
328                         set cmd [list submodule summary --cached -- $path]
329                 } else {
330                         set cmd [list submodule summary --files -- $path]
331                 }
332         }
333
334         if {[catch {set fd [eval git_read --nice $cmd]} err]} {
335                 set diff_active 0
336                 unlock_index
337                 ui_status [mc "Unable to display %s" [escape_path $path]]
338                 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
339                 return
340         }
341
342         set ::current_diff_inheader 1
343         fconfigure $fd \
344                 -blocking 0 \
345                 -encoding [get_path_encoding $path] \
346                 -translation lf
347         fileevent $fd readable [list read_diff $fd $conflict_size $cont_info]
348 }
349
350 proc parse_color_line {line} {
351         set start 0
352         set result ""
353         set markup [list]
354         set regexp {\033\[((?:\d+;)*\d+)?m}
355         set need_reset 0
356         while {[regexp -indices -start $start $regexp $line match code]} {
357                 foreach {begin end} $match break
358                 append result [string range $line $start [expr {$begin - 1}]]
359                 set pos [string length $result]
360                 set col [eval [linsert $code 0 string range $line]]
361                 set start [incr end]
362                 if {$col eq "0" || $col eq ""} {
363                         if {!$need_reset} continue
364                         set need_reset 0
365                 } else {
366                         set need_reset 1
367                 }
368                 lappend markup $pos $col
369         }
370         append result [string range $line $start end]
371         if {[llength $markup] < 4} {set markup {}}
372         return [list $result $markup]
373 }
374
375 proc read_diff {fd conflict_size cont_info} {
376         global ui_diff diff_active is_submodule_diff
377         global is_3way_diff is_conflict_diff current_diff_header
378         global current_diff_queue
379         global diff_empty_count
380
381         $ui_diff conf -state normal
382         while {[gets $fd line] >= 0} {
383                 foreach {line markup} [parse_color_line $line] break
384                 set line [string map {\033 ^} $line]
385
386                 set tags {}
387
388                 # -- Check for start of diff header.
389                 if {   [string match {diff --git *}      $line]
390                     || [string match {diff --cc *}       $line]
391                     || [string match {diff --combined *} $line]} {
392                         set ::current_diff_inheader 1
393                 }
394
395                 # -- Check for end of diff header (any hunk line will do this).
396                 #
397                 if {[regexp {^@@+ } $line]} {set ::current_diff_inheader 0}
398
399                 # -- Automatically detect if this is a 3 way diff.
400                 #
401                 if {[string match {@@@ *} $line]} {set is_3way_diff 1}
402
403                 if {$::current_diff_inheader} {
404
405                         # -- These two lines stop a diff header and shouldn't be in there
406                         if {   [string match {Binary files * and * differ} $line]
407                             || [regexp {^\* Unmerged path }                $line]} {
408                                 set ::current_diff_inheader 0
409                         } else {
410                                 append current_diff_header $line "\n"
411                         }
412
413                         # -- Cleanup uninteresting diff header lines.
414                         #
415                         if {   [string match {diff --git *}      $line]
416                             || [string match {diff --cc *}       $line]
417                             || [string match {diff --combined *} $line]
418                             || [string match {--- *}             $line]
419                             || [string match {+++ *}             $line]
420                             || [string match {index *}           $line]} {
421                                 continue
422                         }
423
424                         # -- Name it symlink, not 120000
425                         #    Note, that the original line is in $current_diff_header
426                         regsub {^(deleted|new) file mode 120000} $line {\1 symlink} line
427
428                 } elseif {   $line eq {\ No newline at end of file}} {
429                         # -- Handle some special lines
430                 } elseif {$is_3way_diff} {
431                         set op [string range $line 0 1]
432                         switch -- $op {
433                         {  } {set tags {}}
434                         {@@} {set tags d_@}
435                         { +} {set tags d_s+}
436                         { -} {set tags d_s-}
437                         {+ } {set tags d_+s}
438                         {- } {set tags d_-s}
439                         {--} {set tags d_--}
440                         {++} {
441                                 set regexp [string map [list %conflict_size $conflict_size]\
442                                                                 {^\+\+([<>=]){%conflict_size}(?: |$)}]
443                                 if {[regexp $regexp $line _g op]} {
444                                         set is_conflict_diff 1
445                                         set line [string replace $line 0 1 {  }]
446                                         set tags d$op
447                                 } else {
448                                         set tags d_++
449                                 }
450                         }
451                         default {
452                                 puts "error: Unhandled 3 way diff marker: {$op}"
453                                 set tags {}
454                         }
455                         }
456                 } elseif {$is_submodule_diff} {
457                         if {$line == ""} continue
458                         if {[regexp {^Submodule } $line]} {
459                                 set tags d_info
460                         } elseif {[regexp {^\* } $line]} {
461                                 set line [string replace $line 0 1 {Submodule }]
462                                 set tags d_info
463                         } else {
464                                 set op [string range $line 0 2]
465                                 switch -- $op {
466                                 {  <} {set tags d_-}
467                                 {  >} {set tags d_+}
468                                 {  W} {set tags {}}
469                                 default {
470                                         puts "error: Unhandled submodule diff marker: {$op}"
471                                         set tags {}
472                                 }
473                                 }
474                         }
475                 } else {
476                         set op [string index $line 0]
477                         switch -- $op {
478                         { } {set tags {}}
479                         {@} {set tags d_@}
480                         {-} {set tags d_-}
481                         {+} {
482                                 set regexp [string map [list %conflict_size $conflict_size]\
483                                                                 {^\+([<>=]){%conflict_size}(?: |$)}]
484                                 if {[regexp $regexp $line _g op]} {
485                                         set is_conflict_diff 1
486                                         set tags d$op
487                                 } else {
488                                         set tags d_+
489                                 }
490                         }
491                         default {
492                                 puts "error: Unhandled 2 way diff marker: {$op}"
493                                 set tags {}
494                         }
495                         }
496                 }
497                 set mark [$ui_diff index "end - 1 line linestart"]
498                 $ui_diff insert end $line $tags
499                 if {[string index $line end] eq "\r"} {
500                         $ui_diff tag add d_cr {end - 2c}
501                 }
502                 $ui_diff insert end "\n" $tags
503
504                 foreach {posbegin colbegin posend colend} $markup {
505                         set prefix clr
506                         foreach style [lsort -integer [split $colbegin ";"]] {
507                                 if {$style eq "7"} {append prefix i; continue}
508                                 if {$style != 4 && ($style < 30 || $style > 47)} {continue}
509                                 set a "$mark linestart + $posbegin chars"
510                                 set b "$mark linestart + $posend chars"
511                                 catch {$ui_diff tag add $prefix$style $a $b}
512                         }
513                 }
514         }
515         $ui_diff conf -state disabled
516
517         if {[eof $fd]} {
518                 close $fd
519
520                 if {$current_diff_queue ne {}} {
521                         advance_diff_queue $cont_info
522                         return
523                 }
524
525                 set diff_active 0
526                 unlock_index
527                 set scroll_pos [lindex $cont_info 0]
528                 if {$scroll_pos ne {}} {
529                         update
530                         $ui_diff yview moveto $scroll_pos
531                 }
532                 ui_ready
533
534                 if {[$ui_diff index end] eq {2.0}} {
535                         handle_empty_diff
536                 } else {
537                         set diff_empty_count 0
538                 }
539
540                 set callback [lindex $cont_info 1]
541                 if {$callback ne {}} {
542                         eval $callback
543                 }
544         }
545 }
546
547 proc apply_hunk {x y} {
548         global current_diff_path current_diff_header current_diff_side
549         global ui_diff ui_index file_states
550
551         if {$current_diff_path eq {} || $current_diff_header eq {}} return
552         if {![lock_index apply_hunk]} return
553
554         set apply_cmd {apply --cached --whitespace=nowarn}
555         set mi [lindex $file_states($current_diff_path) 0]
556         if {$current_diff_side eq $ui_index} {
557                 set failed_msg [mc "Failed to unstage selected hunk."]
558                 lappend apply_cmd --reverse
559                 if {[string index $mi 0] ne {M}} {
560                         unlock_index
561                         return
562                 }
563         } else {
564                 set failed_msg [mc "Failed to stage selected hunk."]
565                 if {[string index $mi 1] ne {M}} {
566                         unlock_index
567                         return
568                 }
569         }
570
571         set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
572         set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
573         if {$s_lno eq {}} {
574                 unlock_index
575                 return
576         }
577
578         set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
579         if {$e_lno eq {}} {
580                 set e_lno end
581         }
582
583         if {[catch {
584                 set enc [get_path_encoding $current_diff_path]
585                 set p [eval git_write $apply_cmd]
586                 fconfigure $p -translation binary -encoding $enc
587                 puts -nonewline $p $current_diff_header
588                 puts -nonewline $p [$ui_diff get $s_lno $e_lno]
589                 close $p} err]} {
590                 error_popup [append $failed_msg "\n\n$err"]
591                 unlock_index
592                 return
593         }
594
595         $ui_diff conf -state normal
596         $ui_diff delete $s_lno $e_lno
597         $ui_diff conf -state disabled
598
599         if {[$ui_diff get 1.0 end] eq "\n"} {
600                 set o _
601         } else {
602                 set o ?
603         }
604
605         if {$current_diff_side eq $ui_index} {
606                 set mi ${o}M
607         } elseif {[string index $mi 0] eq {_}} {
608                 set mi M$o
609         } else {
610                 set mi ?$o
611         }
612         unlock_index
613         display_file $current_diff_path $mi
614         # This should trigger shift to the next changed file
615         if {$o eq {_}} {
616                 reshow_diff
617         }
618 }
619
620 proc apply_range_or_line {x y} {
621         global current_diff_path current_diff_header current_diff_side
622         global ui_diff ui_index file_states
623
624         set selected [$ui_diff tag nextrange sel 0.0]
625
626         if {$selected == {}} {
627                 set first [$ui_diff index "@$x,$y"]
628                 set last $first
629         } else {
630                 set first [lindex $selected 0]
631                 set last [lindex $selected 1]
632         }
633
634         set first_l [$ui_diff index "$first linestart"]
635         set last_l [$ui_diff index "$last lineend"]
636
637         if {$current_diff_path eq {} || $current_diff_header eq {}} return
638         if {![lock_index apply_hunk]} return
639
640         set apply_cmd {apply --cached --whitespace=nowarn}
641         set mi [lindex $file_states($current_diff_path) 0]
642         if {$current_diff_side eq $ui_index} {
643                 set failed_msg [mc "Failed to unstage selected line."]
644                 set to_context {+}
645                 lappend apply_cmd --reverse
646                 if {[string index $mi 0] ne {M}} {
647                         unlock_index
648                         return
649                 }
650         } else {
651                 set failed_msg [mc "Failed to stage selected line."]
652                 set to_context {-}
653                 if {[string index $mi 1] ne {M}} {
654                         unlock_index
655                         return
656                 }
657         }
658
659         set wholepatch {}
660
661         while {$first_l < $last_l} {
662                 set i_l [$ui_diff search -backwards -regexp ^@@ $first_l 0.0]
663                 if {$i_l eq {}} {
664                         # If there's not a @@ above, then the selected range
665                         # must have come before the first_l @@
666                         set i_l [$ui_diff search -regexp ^@@ $first_l $last_l]
667                 }
668                 if {$i_l eq {}} {
669                         unlock_index
670                         return
671                 }
672                 # $i_l is now at the beginning of a line
673
674                 # pick start line number from hunk header
675                 set hh [$ui_diff get $i_l "$i_l + 1 lines"]
676                 set hh [lindex [split $hh ,] 0]
677                 set hln [lindex [split $hh -] 1]
678
679                 # There is a special situation to take care of. Consider this
680                 # hunk:
681                 #
682                 #    @@ -10,4 +10,4 @@
683                 #     context before
684                 #    -old 1
685                 #    -old 2
686                 #    +new 1
687                 #    +new 2
688                 #     context after
689                 #
690                 # We used to keep the context lines in the order they appear in
691                 # the hunk. But then it is not possible to correctly stage only
692                 # "-old 1" and "+new 1" - it would result in this staged text:
693                 #
694                 #    context before
695                 #    old 2
696                 #    new 1
697                 #    context after
698                 #
699                 # (By symmetry it is not possible to *un*stage "old 2" and "new
700                 # 2".)
701                 #
702                 # We resolve the problem by introducing an asymmetry, namely,
703                 # when a "+" line is *staged*, it is moved in front of the
704                 # context lines that are generated from the "-" lines that are
705                 # immediately before the "+" block. That is, we construct this
706                 # patch:
707                 #
708                 #    @@ -10,4 +10,5 @@
709                 #     context before
710                 #    +new 1
711                 #     old 1
712                 #     old 2
713                 #     context after
714                 #
715                 # But we do *not* treat "-" lines that are *un*staged in a
716                 # special way.
717                 #
718                 # With this asymmetry it is possible to stage the change "old
719                 # 1" -> "new 1" directly, and to stage the change "old 2" ->
720                 # "new 2" by first staging the entire hunk and then unstaging
721                 # the change "old 1" -> "new 1".
722                 #
723                 # Applying multiple lines adds complexity to the special
724                 # situation.  The pre_context must be moved after the entire
725                 # first block of consecutive staged "+" lines, so that
726                 # staging both additions gives the following patch:
727                 #
728                 #    @@ -10,4 +10,6 @@
729                 #     context before
730                 #    +new 1
731                 #    +new 2
732                 #     old 1
733                 #     old 2
734                 #     context after
735
736                 # This is non-empty if and only if we are _staging_ changes;
737                 # then it accumulates the consecutive "-" lines (after
738                 # converting them to context lines) in order to be moved after
739                 # "+" change lines.
740                 set pre_context {}
741
742                 set n 0
743                 set m 0
744                 set i_l [$ui_diff index "$i_l + 1 lines"]
745                 set patch {}
746                 while {[$ui_diff compare $i_l < "end - 1 chars"] &&
747                        [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
748                         set next_l [$ui_diff index "$i_l + 1 lines"]
749                         set c1 [$ui_diff get $i_l]
750                         if {[$ui_diff compare $first_l <= $i_l] &&
751                             [$ui_diff compare $i_l < $last_l] &&
752                             ($c1 eq {-} || $c1 eq {+})} {
753                                 # a line to stage/unstage
754                                 set ln [$ui_diff get $i_l $next_l]
755                                 if {$c1 eq {-}} {
756                                         set n [expr $n+1]
757                                         set patch "$patch$pre_context$ln"
758                                         set pre_context {}
759                                 } else {
760                                         set m [expr $m+1]
761                                         set patch "$patch$ln"
762                                 }
763                         } elseif {$c1 ne {-} && $c1 ne {+}} {
764                                 # context line
765                                 set ln [$ui_diff get $i_l $next_l]
766                                 set patch "$patch$pre_context$ln"
767                                 set n [expr $n+1]
768                                 set m [expr $m+1]
769                                 set pre_context {}
770                         } elseif {$c1 eq $to_context} {
771                                 # turn change line into context line
772                                 set ln [$ui_diff get "$i_l + 1 chars" $next_l]
773                                 if {$c1 eq {-}} {
774                                         set pre_context "$pre_context $ln"
775                                 } else {
776                                         set patch "$patch $ln"
777                                 }
778                                 set n [expr $n+1]
779                                 set m [expr $m+1]
780                         } else {
781                                 # a change in the opposite direction of
782                                 # to_context which is outside the range of
783                                 # lines to apply.
784                                 set patch "$patch$pre_context"
785                                 set pre_context {}
786                         }
787                         set i_l $next_l
788                 }
789                 set patch "$patch$pre_context"
790                 set wholepatch "$wholepatch@@ -$hln,$n +$hln,$m @@\n$patch"
791                 set first_l [$ui_diff index "$next_l + 1 lines"]
792         }
793
794         if {[catch {
795                 set enc [get_path_encoding $current_diff_path]
796                 set p [eval git_write $apply_cmd]
797                 fconfigure $p -translation binary -encoding $enc
798                 puts -nonewline $p $current_diff_header
799                 puts -nonewline $p $wholepatch
800                 close $p} err]} {
801                 error_popup [append $failed_msg "\n\n$err"]
802         }
803
804         unlock_index
805 }