git-gui: Avoid an infinite rescan loop in handle_empty_diff.
[git] / 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 $s 0] ne {_M}} return
59
60         # Prevent infinite rescan loops
61         incr diff_empty_count
62         if {$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_@
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_@
219                 }
220                 if {[string first "\0" $content] != -1} {
221                         $ui_diff insert end \
222                                 [mc "* Binary file (not showing content)."] \
223                                 d_@
224                 } else {
225                         if {$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_@
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_@
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 start_show_diff {cont_info {add_opts {}}} {
257         global file_states file_lists
258         global is_3way_diff diff_active repo_config
259         global ui_diff ui_index ui_workdir
260         global current_diff_path current_diff_side current_diff_header
261
262         set path $current_diff_path
263         set w $current_diff_side
264
265         set s $file_states($path)
266         set m [lindex $s 0]
267         set is_3way_diff 0
268         set diff_active 1
269         set current_diff_header {}
270
271         set cmd [list]
272         if {$w eq $ui_index} {
273                 lappend cmd diff-index
274                 lappend cmd --cached
275         } elseif {$w eq $ui_workdir} {
276                 if {[string first {U} $m] >= 0} {
277                         lappend cmd diff
278                 } else {
279                         lappend cmd diff-files
280                 }
281         }
282
283         lappend cmd -p
284         lappend cmd --no-color
285         if {$repo_config(gui.diffcontext) >= 1} {
286                 lappend cmd "-U$repo_config(gui.diffcontext)"
287         }
288         if {$w eq $ui_index} {
289                 lappend cmd [PARENT]
290         }
291         if {$add_opts ne {}} {
292                 eval lappend cmd $add_opts
293         } else {
294                 lappend cmd --
295                 lappend cmd $path
296         }
297
298         if {[catch {set fd [eval git_read --nice $cmd]} err]} {
299                 set diff_active 0
300                 unlock_index
301                 ui_status [mc "Unable to display %s" [escape_path $path]]
302                 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
303                 return
304         }
305
306         set ::current_diff_inheader 1
307         fconfigure $fd \
308                 -blocking 0 \
309                 -encoding [get_path_encoding $path] \
310                 -translation lf
311         fileevent $fd readable [list read_diff $fd $cont_info]
312 }
313
314 proc read_diff {fd cont_info} {
315         global ui_diff diff_active
316         global is_3way_diff is_conflict_diff current_diff_header
317         global current_diff_queue
318         global diff_empty_count
319
320         $ui_diff conf -state normal
321         while {[gets $fd line] >= 0} {
322                 # -- Cleanup uninteresting diff header lines.
323                 #
324                 if {$::current_diff_inheader} {
325                         if {   [string match {diff --git *}      $line]
326                             || [string match {diff --cc *}       $line]
327                             || [string match {diff --combined *} $line]
328                             || [string match {--- *}             $line]
329                             || [string match {+++ *}             $line]} {
330                                 append current_diff_header $line "\n"
331                                 continue
332                         }
333                 }
334                 if {[string match {index *} $line]} continue
335                 if {$line eq {deleted file mode 120000}} {
336                         set line "deleted symlink"
337                 }
338                 set ::current_diff_inheader 0
339
340                 # -- Automatically detect if this is a 3 way diff.
341                 #
342                 if {[string match {@@@ *} $line]} {set is_3way_diff 1}
343
344                 if {[string match {mode *} $line]
345                         || [string match {new file *} $line]
346                         || [regexp {^(old|new) mode *} $line]
347                         || [string match {deleted file *} $line]
348                         || [string match {deleted symlink} $line]
349                         || [string match {Binary files * and * differ} $line]
350                         || $line eq {\ No newline at end of file}
351                         || [regexp {^\* Unmerged path } $line]} {
352                         set tags {}
353                 } elseif {$is_3way_diff} {
354                         set op [string range $line 0 1]
355                         switch -- $op {
356                         {  } {set tags {}}
357                         {@@} {set tags d_@}
358                         { +} {set tags d_s+}
359                         { -} {set tags d_s-}
360                         {+ } {set tags d_+s}
361                         {- } {set tags d_-s}
362                         {--} {set tags d_--}
363                         {++} {
364                                 if {[regexp {^\+\+([<>]{7} |={7})} $line _g op]} {
365                                         set is_conflict_diff 1
366                                         set line [string replace $line 0 1 {  }]
367                                         set tags d$op
368                                 } else {
369                                         set tags d_++
370                                 }
371                         }
372                         default {
373                                 puts "error: Unhandled 3 way diff marker: {$op}"
374                                 set tags {}
375                         }
376                         }
377                 } else {
378                         set op [string index $line 0]
379                         switch -- $op {
380                         { } {set tags {}}
381                         {@} {set tags d_@}
382                         {-} {set tags d_-}
383                         {+} {
384                                 if {[regexp {^\+([<>]{7} |={7})} $line _g op]} {
385                                         set is_conflict_diff 1
386                                         set tags d$op
387                                 } else {
388                                         set tags d_+
389                                 }
390                         }
391                         default {
392                                 puts "error: Unhandled 2 way diff marker: {$op}"
393                                 set tags {}
394                         }
395                         }
396                 }
397                 $ui_diff insert end $line $tags
398                 if {[string index $line end] eq "\r"} {
399                         $ui_diff tag add d_cr {end - 2c}
400                 }
401                 $ui_diff insert end "\n" $tags
402         }
403         $ui_diff conf -state disabled
404
405         if {[eof $fd]} {
406                 close $fd
407
408                 if {$current_diff_queue ne {}} {
409                         advance_diff_queue $cont_info
410                         return
411                 }
412
413                 set diff_active 0
414                 unlock_index
415                 set scroll_pos [lindex $cont_info 0]
416                 if {$scroll_pos ne {}} {
417                         update
418                         $ui_diff yview moveto $scroll_pos
419                 }
420                 ui_ready
421
422                 if {[$ui_diff index end] eq {2.0}} {
423                         handle_empty_diff
424                 } else {
425                         set diff_empty_count 0
426                 }
427
428                 set callback [lindex $cont_info 1]
429                 if {$callback ne {}} {
430                         eval $callback
431                 }
432         }
433 }
434
435 proc apply_hunk {x y} {
436         global current_diff_path current_diff_header current_diff_side
437         global ui_diff ui_index file_states
438
439         if {$current_diff_path eq {} || $current_diff_header eq {}} return
440         if {![lock_index apply_hunk]} return
441
442         set apply_cmd {apply --cached --whitespace=nowarn}
443         set mi [lindex $file_states($current_diff_path) 0]
444         if {$current_diff_side eq $ui_index} {
445                 set failed_msg [mc "Failed to unstage selected hunk."]
446                 lappend apply_cmd --reverse
447                 if {[string index $mi 0] ne {M}} {
448                         unlock_index
449                         return
450                 }
451         } else {
452                 set failed_msg [mc "Failed to stage selected hunk."]
453                 if {[string index $mi 1] ne {M}} {
454                         unlock_index
455                         return
456                 }
457         }
458
459         set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
460         set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
461         if {$s_lno eq {}} {
462                 unlock_index
463                 return
464         }
465
466         set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
467         if {$e_lno eq {}} {
468                 set e_lno end
469         }
470
471         if {[catch {
472                 set enc [get_path_encoding $current_diff_path]
473                 set p [eval git_write $apply_cmd]
474                 fconfigure $p -translation binary -encoding $enc
475                 puts -nonewline $p $current_diff_header
476                 puts -nonewline $p [$ui_diff get $s_lno $e_lno]
477                 close $p} err]} {
478                 error_popup [append $failed_msg "\n\n$err"]
479                 unlock_index
480                 return
481         }
482
483         $ui_diff conf -state normal
484         $ui_diff delete $s_lno $e_lno
485         $ui_diff conf -state disabled
486
487         if {[$ui_diff get 1.0 end] eq "\n"} {
488                 set o _
489         } else {
490                 set o ?
491         }
492
493         if {$current_diff_side eq $ui_index} {
494                 set mi ${o}M
495         } elseif {[string index $mi 0] eq {_}} {
496                 set mi M$o
497         } else {
498                 set mi ?$o
499         }
500         unlock_index
501         display_file $current_diff_path $mi
502         # This should trigger shift to the next changed file
503         if {$o eq {_}} {
504                 reshow_diff
505         }
506 }
507
508 proc apply_line {x y} {
509         global current_diff_path current_diff_header current_diff_side
510         global ui_diff ui_index file_states
511
512         if {$current_diff_path eq {} || $current_diff_header eq {}} return
513         if {![lock_index apply_hunk]} return
514
515         set apply_cmd {apply --cached --whitespace=nowarn}
516         set mi [lindex $file_states($current_diff_path) 0]
517         if {$current_diff_side eq $ui_index} {
518                 set failed_msg [mc "Failed to unstage selected line."]
519                 set to_context {+}
520                 lappend apply_cmd --reverse
521                 if {[string index $mi 0] ne {M}} {
522                         unlock_index
523                         return
524                 }
525         } else {
526                 set failed_msg [mc "Failed to stage selected line."]
527                 set to_context {-}
528                 if {[string index $mi 1] ne {M}} {
529                         unlock_index
530                         return
531                 }
532         }
533
534         set the_l [$ui_diff index @$x,$y]
535
536         # operate only on change lines
537         set c1 [$ui_diff get "$the_l linestart"]
538         if {$c1 ne {+} && $c1 ne {-}} {
539                 unlock_index
540                 return
541         }
542         set sign $c1
543
544         set i_l [$ui_diff search -backwards -regexp ^@@ $the_l 0.0]
545         if {$i_l eq {}} {
546                 unlock_index
547                 return
548         }
549         # $i_l is now at the beginning of a line
550
551         # pick start line number from hunk header
552         set hh [$ui_diff get $i_l "$i_l + 1 lines"]
553         set hh [lindex [split $hh ,] 0]
554         set hln [lindex [split $hh -] 1]
555
556         # There is a special situation to take care of. Consider this hunk:
557         #
558         #    @@ -10,4 +10,4 @@
559         #     context before
560         #    -old 1
561         #    -old 2
562         #    +new 1
563         #    +new 2
564         #     context after
565         #
566         # We used to keep the context lines in the order they appear in the
567         # hunk. But then it is not possible to correctly stage only
568         # "-old 1" and "+new 1" - it would result in this staged text:
569         #
570         #    context before
571         #    old 2
572         #    new 1
573         #    context after
574         #
575         # (By symmetry it is not possible to *un*stage "old 2" and "new 2".)
576         #
577         # We resolve the problem by introducing an asymmetry, namely, when
578         # a "+" line is *staged*, it is moved in front of the context lines
579         # that are generated from the "-" lines that are immediately before
580         # the "+" block. That is, we construct this patch:
581         #
582         #    @@ -10,4 +10,5 @@
583         #     context before
584         #    +new 1
585         #     old 1
586         #     old 2
587         #     context after
588         #
589         # But we do *not* treat "-" lines that are *un*staged in a special
590         # way.
591         #
592         # With this asymmetry it is possible to stage the change
593         # "old 1" -> "new 1" directly, and to stage the change
594         # "old 2" -> "new 2" by first staging the entire hunk and
595         # then unstaging the change "old 1" -> "new 1".
596
597         # This is non-empty if and only if we are _staging_ changes;
598         # then it accumulates the consecutive "-" lines (after converting
599         # them to context lines) in order to be moved after the "+" change
600         # line.
601         set pre_context {}
602
603         set n 0
604         set i_l [$ui_diff index "$i_l + 1 lines"]
605         set patch {}
606         while {[$ui_diff compare $i_l < "end - 1 chars"] &&
607                [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
608                 set next_l [$ui_diff index "$i_l + 1 lines"]
609                 set c1 [$ui_diff get $i_l]
610                 if {[$ui_diff compare $i_l <= $the_l] &&
611                     [$ui_diff compare $the_l < $next_l]} {
612                         # the line to stage/unstage
613                         set ln [$ui_diff get $i_l $next_l]
614                         if {$c1 eq {-}} {
615                                 set n [expr $n+1]
616                                 set patch "$patch$pre_context$ln"
617                         } else {
618                                 set patch "$patch$ln$pre_context"
619                         }
620                         set pre_context {}
621                 } elseif {$c1 ne {-} && $c1 ne {+}} {
622                         # context line
623                         set ln [$ui_diff get $i_l $next_l]
624                         set patch "$patch$pre_context$ln"
625                         set n [expr $n+1]
626                         set pre_context {}
627                 } elseif {$c1 eq $to_context} {
628                         # turn change line into context line
629                         set ln [$ui_diff get "$i_l + 1 chars" $next_l]
630                         if {$c1 eq {-}} {
631                                 set pre_context "$pre_context $ln"
632                         } else {
633                                 set patch "$patch $ln"
634                         }
635                         set n [expr $n+1]
636                 }
637                 set i_l $next_l
638         }
639         set patch "@@ -$hln,$n +$hln,[eval expr $n $sign 1] @@\n$patch"
640
641         if {[catch {
642                 set enc [get_path_encoding $current_diff_path]
643                 set p [eval git_write $apply_cmd]
644                 fconfigure $p -translation binary -encoding $enc
645                 puts -nonewline $p $current_diff_header
646                 puts -nonewline $p $patch
647                 close $p} err]} {
648                 error_popup [append $failed_msg "\n\n$err"]
649         }
650
651         unlock_index
652 }