Merge branch '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 $ui_index} {
288                 lappend cmd diff-index
289                 lappend cmd --cached
290                 if {[git-version >= "1.7.2"]} {
291                         lappend cmd --ignore-submodules=dirty
292                 }
293         } elseif {$w eq $ui_workdir} {
294                 if {[string first {U} $m] >= 0} {
295                         lappend cmd diff
296                 } else {
297                         lappend cmd diff-files
298                 }
299         }
300         if {![is_config_false gui.textconv] && [git-version >= 1.6.1]} {
301                 lappend cmd --textconv
302         }
303
304         if {[string match {160000 *} [lindex $s 2]]
305          || [string match {160000 *} [lindex $s 3]]} {
306                 set is_submodule_diff 1
307
308                 if {[git-version >= "1.6.6"]} {
309                         lappend cmd --submodule
310                 }
311         }
312
313         lappend cmd -p
314         lappend cmd --color
315         set cmd [concat $cmd $repo_config(gui.diffopts)]
316         if {$repo_config(gui.diffcontext) >= 1} {
317                 lappend cmd "-U$repo_config(gui.diffcontext)"
318         }
319         if {$w eq $ui_index} {
320                 lappend cmd [PARENT]
321         }
322         if {$add_opts ne {}} {
323                 eval lappend cmd $add_opts
324         } else {
325                 lappend cmd --
326                 lappend cmd $path
327         }
328
329         if {$is_submodule_diff && [git-version < "1.6.6"]} {
330                 if {$w eq $ui_index} {
331                         set cmd [list submodule summary --cached -- $path]
332                 } else {
333                         set cmd [list submodule summary --files -- $path]
334                 }
335         }
336
337         if {[catch {set fd [eval git_read --nice $cmd]} err]} {
338                 set diff_active 0
339                 unlock_index
340                 ui_status [mc "Unable to display %s" [escape_path $path]]
341                 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
342                 return
343         }
344
345         set ::current_diff_inheader 1
346         fconfigure $fd \
347                 -blocking 0 \
348                 -encoding [get_path_encoding $path] \
349                 -translation lf
350         fileevent $fd readable [list read_diff $fd $conflict_size $cont_info]
351 }
352
353 proc parse_color_line {line} {
354         set start 0
355         set result ""
356         set markup [list]
357         set regexp {\033\[((?:\d+;)*\d+)?m}
358         set need_reset 0
359         while {[regexp -indices -start $start $regexp $line match code]} {
360                 foreach {begin end} $match break
361                 append result [string range $line $start [expr {$begin - 1}]]
362                 set pos [string length $result]
363                 set col [eval [linsert $code 0 string range $line]]
364                 set start [incr end]
365                 if {$col eq "0" || $col eq ""} {
366                         if {!$need_reset} continue
367                         set need_reset 0
368                 } else {
369                         set need_reset 1
370                 }
371                 lappend markup $pos $col
372         }
373         append result [string range $line $start end]
374         if {[llength $markup] < 4} {set markup {}}
375         return [list $result $markup]
376 }
377
378 proc read_diff {fd conflict_size cont_info} {
379         global ui_diff diff_active is_submodule_diff
380         global is_3way_diff is_conflict_diff current_diff_header
381         global current_diff_queue
382         global diff_empty_count
383
384         $ui_diff conf -state normal
385         while {[gets $fd line] >= 0} {
386                 foreach {line markup} [parse_color_line $line] break
387                 set line [string map {\033 ^} $line]
388
389                 set tags {}
390
391                 # -- Check for start of diff header.
392                 if {   [string match {diff --git *}      $line]
393                     || [string match {diff --cc *}       $line]
394                     || [string match {diff --combined *} $line]} {
395                         set ::current_diff_inheader 1
396                 }
397
398                 # -- Check for end of diff header (any hunk line will do this).
399                 #
400                 if {[regexp {^@@+ } $line]} {set ::current_diff_inheader 0}
401
402                 # -- Automatically detect if this is a 3 way diff.
403                 #
404                 if {[string match {@@@ *} $line]} {set is_3way_diff 1}
405
406                 if {$::current_diff_inheader} {
407
408                         # -- These two lines stop a diff header and shouldn't be in there
409                         if {   [string match {Binary files * and * differ} $line]
410                             || [regexp {^\* Unmerged path }                $line]} {
411                                 set ::current_diff_inheader 0
412                         } else {
413                                 append current_diff_header $line "\n"
414                         }
415
416                         # -- Cleanup uninteresting diff header lines.
417                         #
418                         if {   [string match {diff --git *}      $line]
419                             || [string match {diff --cc *}       $line]
420                             || [string match {diff --combined *} $line]
421                             || [string match {--- *}             $line]
422                             || [string match {+++ *}             $line]
423                             || [string match {index *}           $line]} {
424                                 continue
425                         }
426
427                         # -- Name it symlink, not 120000
428                         #    Note, that the original line is in $current_diff_header
429                         regsub {^(deleted|new) file mode 120000} $line {\1 symlink} line
430
431                 } elseif {   $line eq {\ No newline at end of file}} {
432                         # -- Handle some special lines
433                 } elseif {$is_3way_diff} {
434                         set op [string range $line 0 1]
435                         switch -- $op {
436                         {  } {set tags {}}
437                         {@@} {set tags d_@}
438                         { +} {set tags d_s+}
439                         { -} {set tags d_s-}
440                         {+ } {set tags d_+s}
441                         {- } {set tags d_-s}
442                         {--} {set tags d_--}
443                         {++} {
444                                 set regexp [string map [list %conflict_size $conflict_size]\
445                                                                 {^\+\+([<>=]){%conflict_size}(?: |$)}]
446                                 if {[regexp $regexp $line _g op]} {
447                                         set is_conflict_diff 1
448                                         set line [string replace $line 0 1 {  }]
449                                         set tags d$op
450                                 } else {
451                                         set tags d_++
452                                 }
453                         }
454                         default {
455                                 puts "error: Unhandled 3 way diff marker: {$op}"
456                                 set tags {}
457                         }
458                         }
459                 } elseif {$is_submodule_diff} {
460                         if {$line == ""} continue
461                         if {[regexp {^Submodule } $line]} {
462                                 set tags d_info
463                         } elseif {[regexp {^\* } $line]} {
464                                 set line [string replace $line 0 1 {Submodule }]
465                                 set tags d_info
466                         } else {
467                                 set op [string range $line 0 2]
468                                 switch -- $op {
469                                 {  <} {set tags d_-}
470                                 {  >} {set tags d_+}
471                                 {  W} {set tags {}}
472                                 default {
473                                         puts "error: Unhandled submodule diff marker: {$op}"
474                                         set tags {}
475                                 }
476                                 }
477                         }
478                 } else {
479                         set op [string index $line 0]
480                         switch -- $op {
481                         { } {set tags {}}
482                         {@} {set tags d_@}
483                         {-} {set tags d_-}
484                         {+} {
485                                 set regexp [string map [list %conflict_size $conflict_size]\
486                                                                 {^\+([<>=]){%conflict_size}(?: |$)}]
487                                 if {[regexp $regexp $line _g op]} {
488                                         set is_conflict_diff 1
489                                         set tags d$op
490                                 } else {
491                                         set tags d_+
492                                 }
493                         }
494                         default {
495                                 puts "error: Unhandled 2 way diff marker: {$op}"
496                                 set tags {}
497                         }
498                         }
499                 }
500                 set mark [$ui_diff index "end - 1 line linestart"]
501                 $ui_diff insert end $line $tags
502                 if {[string index $line end] eq "\r"} {
503                         $ui_diff tag add d_cr {end - 2c}
504                 }
505                 $ui_diff insert end "\n" $tags
506
507                 foreach {posbegin colbegin posend colend} $markup {
508                         set prefix clr
509                         foreach style [lsort -integer [split $colbegin ";"]] {
510                                 if {$style eq "7"} {append prefix i; continue}
511                                 if {$style != 4 && ($style < 30 || $style > 47)} {continue}
512                                 set a "$mark linestart + $posbegin chars"
513                                 set b "$mark linestart + $posend chars"
514                                 catch {$ui_diff tag add $prefix$style $a $b}
515                         }
516                 }
517         }
518         $ui_diff conf -state disabled
519
520         if {[eof $fd]} {
521                 close $fd
522
523                 if {$current_diff_queue ne {}} {
524                         advance_diff_queue $cont_info
525                         return
526                 }
527
528                 set diff_active 0
529                 unlock_index
530                 set scroll_pos [lindex $cont_info 0]
531                 if {$scroll_pos ne {}} {
532                         update
533                         $ui_diff yview moveto $scroll_pos
534                 }
535                 ui_ready
536
537                 if {[$ui_diff index end] eq {2.0}} {
538                         handle_empty_diff
539                 } else {
540                         set diff_empty_count 0
541                 }
542
543                 set callback [lindex $cont_info 1]
544                 if {$callback ne {}} {
545                         eval $callback
546                 }
547         }
548 }
549
550 proc apply_hunk {x y} {
551         global current_diff_path current_diff_header current_diff_side
552         global ui_diff ui_index file_states
553
554         if {$current_diff_path eq {} || $current_diff_header eq {}} return
555         if {![lock_index apply_hunk]} return
556
557         set apply_cmd {apply --cached --whitespace=nowarn}
558         set mi [lindex $file_states($current_diff_path) 0]
559         if {$current_diff_side eq $ui_index} {
560                 set failed_msg [mc "Failed to unstage selected hunk."]
561                 lappend apply_cmd --reverse
562                 if {[string index $mi 0] ne {M}} {
563                         unlock_index
564                         return
565                 }
566         } else {
567                 set failed_msg [mc "Failed to stage selected hunk."]
568                 if {[string index $mi 1] ne {M}} {
569                         unlock_index
570                         return
571                 }
572         }
573
574         set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
575         set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
576         if {$s_lno eq {}} {
577                 unlock_index
578                 return
579         }
580
581         set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
582         if {$e_lno eq {}} {
583                 set e_lno end
584         }
585
586         if {[catch {
587                 set enc [get_path_encoding $current_diff_path]
588                 set p [eval git_write $apply_cmd]
589                 fconfigure $p -translation binary -encoding $enc
590                 puts -nonewline $p $current_diff_header
591                 puts -nonewline $p [$ui_diff get $s_lno $e_lno]
592                 close $p} err]} {
593                 error_popup [append $failed_msg "\n\n$err"]
594                 unlock_index
595                 return
596         }
597
598         $ui_diff conf -state normal
599         $ui_diff delete $s_lno $e_lno
600         $ui_diff conf -state disabled
601
602         if {[$ui_diff get 1.0 end] eq "\n"} {
603                 set o _
604         } else {
605                 set o ?
606         }
607
608         if {$current_diff_side eq $ui_index} {
609                 set mi ${o}M
610         } elseif {[string index $mi 0] eq {_}} {
611                 set mi M$o
612         } else {
613                 set mi ?$o
614         }
615         unlock_index
616         display_file $current_diff_path $mi
617         # This should trigger shift to the next changed file
618         if {$o eq {_}} {
619                 reshow_diff
620         }
621 }
622
623 proc apply_range_or_line {x y} {
624         global current_diff_path current_diff_header current_diff_side
625         global ui_diff ui_index file_states
626
627         set selected [$ui_diff tag nextrange sel 0.0]
628
629         if {$selected == {}} {
630                 set first [$ui_diff index "@$x,$y"]
631                 set last $first
632         } else {
633                 set first [lindex $selected 0]
634                 set last [lindex $selected 1]
635         }
636
637         set first_l [$ui_diff index "$first linestart"]
638         set last_l [$ui_diff index "$last lineend"]
639
640         if {$current_diff_path eq {} || $current_diff_header eq {}} return
641         if {![lock_index apply_hunk]} return
642
643         set apply_cmd {apply --cached --whitespace=nowarn}
644         set mi [lindex $file_states($current_diff_path) 0]
645         if {$current_diff_side eq $ui_index} {
646                 set failed_msg [mc "Failed to unstage selected line."]
647                 set to_context {+}
648                 lappend apply_cmd --reverse
649                 if {[string index $mi 0] ne {M}} {
650                         unlock_index
651                         return
652                 }
653         } else {
654                 set failed_msg [mc "Failed to stage selected line."]
655                 set to_context {-}
656                 if {[string index $mi 1] ne {M}} {
657                         unlock_index
658                         return
659                 }
660         }
661
662         set wholepatch {}
663
664         while {$first_l < $last_l} {
665                 set i_l [$ui_diff search -backwards -regexp ^@@ $first_l 0.0]
666                 if {$i_l eq {}} {
667                         # If there's not a @@ above, then the selected range
668                         # must have come before the first_l @@
669                         set i_l [$ui_diff search -regexp ^@@ $first_l $last_l]
670                 }
671                 if {$i_l eq {}} {
672                         unlock_index
673                         return
674                 }
675                 # $i_l is now at the beginning of a line
676
677                 # pick start line number from hunk header
678                 set hh [$ui_diff get $i_l "$i_l + 1 lines"]
679                 set hh [lindex [split $hh ,] 0]
680                 set hln [lindex [split $hh -] 1]
681
682                 # There is a special situation to take care of. Consider this
683                 # hunk:
684                 #
685                 #    @@ -10,4 +10,4 @@
686                 #     context before
687                 #    -old 1
688                 #    -old 2
689                 #    +new 1
690                 #    +new 2
691                 #     context after
692                 #
693                 # We used to keep the context lines in the order they appear in
694                 # the hunk. But then it is not possible to correctly stage only
695                 # "-old 1" and "+new 1" - it would result in this staged text:
696                 #
697                 #    context before
698                 #    old 2
699                 #    new 1
700                 #    context after
701                 #
702                 # (By symmetry it is not possible to *un*stage "old 2" and "new
703                 # 2".)
704                 #
705                 # We resolve the problem by introducing an asymmetry, namely,
706                 # when a "+" line is *staged*, it is moved in front of the
707                 # context lines that are generated from the "-" lines that are
708                 # immediately before the "+" block. That is, we construct this
709                 # patch:
710                 #
711                 #    @@ -10,4 +10,5 @@
712                 #     context before
713                 #    +new 1
714                 #     old 1
715                 #     old 2
716                 #     context after
717                 #
718                 # But we do *not* treat "-" lines that are *un*staged in a
719                 # special way.
720                 #
721                 # With this asymmetry it is possible to stage the change "old
722                 # 1" -> "new 1" directly, and to stage the change "old 2" ->
723                 # "new 2" by first staging the entire hunk and then unstaging
724                 # the change "old 1" -> "new 1".
725                 #
726                 # Applying multiple lines adds complexity to the special
727                 # situation.  The pre_context must be moved after the entire
728                 # first block of consecutive staged "+" lines, so that
729                 # staging both additions gives the following patch:
730                 #
731                 #    @@ -10,4 +10,6 @@
732                 #     context before
733                 #    +new 1
734                 #    +new 2
735                 #     old 1
736                 #     old 2
737                 #     context after
738
739                 # This is non-empty if and only if we are _staging_ changes;
740                 # then it accumulates the consecutive "-" lines (after
741                 # converting them to context lines) in order to be moved after
742                 # "+" change lines.
743                 set pre_context {}
744
745                 set n 0
746                 set m 0
747                 set i_l [$ui_diff index "$i_l + 1 lines"]
748                 set patch {}
749                 while {[$ui_diff compare $i_l < "end - 1 chars"] &&
750                        [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
751                         set next_l [$ui_diff index "$i_l + 1 lines"]
752                         set c1 [$ui_diff get $i_l]
753                         if {[$ui_diff compare $first_l <= $i_l] &&
754                             [$ui_diff compare $i_l < $last_l] &&
755                             ($c1 eq {-} || $c1 eq {+})} {
756                                 # a line to stage/unstage
757                                 set ln [$ui_diff get $i_l $next_l]
758                                 if {$c1 eq {-}} {
759                                         set n [expr $n+1]
760                                         set patch "$patch$pre_context$ln"
761                                         set pre_context {}
762                                 } else {
763                                         set m [expr $m+1]
764                                         set patch "$patch$ln"
765                                 }
766                         } elseif {$c1 ne {-} && $c1 ne {+}} {
767                                 # context line
768                                 set ln [$ui_diff get $i_l $next_l]
769                                 set patch "$patch$pre_context$ln"
770                                 # Skip the "\ No newline at end of
771                                 # file". Depending on the locale setting
772                                 # we don't know what this line looks
773                                 # like exactly. The only thing we do
774                                 # know is that it starts with "\ "
775                                 if {![string match {\\ *} $ln]} {
776                                         set n [expr $n+1]
777                                         set m [expr $m+1]
778                                 }
779                                 set pre_context {}
780                         } elseif {$c1 eq $to_context} {
781                                 # turn change line into context line
782                                 set ln [$ui_diff get "$i_l + 1 chars" $next_l]
783                                 if {$c1 eq {-}} {
784                                         set pre_context "$pre_context $ln"
785                                 } else {
786                                         set patch "$patch $ln"
787                                 }
788                                 set n [expr $n+1]
789                                 set m [expr $m+1]
790                         } else {
791                                 # a change in the opposite direction of
792                                 # to_context which is outside the range of
793                                 # lines to apply.
794                                 set patch "$patch$pre_context"
795                                 set pre_context {}
796                         }
797                         set i_l $next_l
798                 }
799                 set patch "$patch$pre_context"
800                 set wholepatch "$wholepatch@@ -$hln,$n +$hln,$m @@\n$patch"
801                 set first_l [$ui_diff index "$next_l + 1 lines"]
802         }
803
804         if {[catch {
805                 set enc [get_path_encoding $current_diff_path]
806                 set p [eval git_write $apply_cmd]
807                 fconfigure $p -translation binary -encoding $enc
808                 puts -nonewline $p $current_diff_header
809                 puts -nonewline $p $wholepatch
810                 close $p} err]} {
811                 error_popup [append $failed_msg "\n\n$err"]
812         }
813
814         unlock_index
815 }