git gui: show diffs with a minimum of 1 context line
[git/git.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 {} {
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 || [catch {set s $file_states($p)}]
29 || [lsearch -sorted -exact $file_lists($current_diff_side) $p] == -1} {
30 clear_diff
31 } else {
32 set save_pos [lindex [$ui_diff yview] 0]
33 show_diff $p $current_diff_side {} $save_pos
34 }
35 }
36
37 proc handle_empty_diff {} {
38 global current_diff_path file_states file_lists
39
40 set path $current_diff_path
41 set s $file_states($path)
42 if {[lindex $s 0] ne {_M}} return
43
44 info_popup [mc "No differences detected.
45
46 %s has no changes.
47
48 The modification date of this file was updated by another application, but the content within the file was not changed.
49
50 A rescan will be automatically started to find other files which may have the same state." [short_path $path]]
51
52 clear_diff
53 display_file $path __
54 rescan ui_ready 0
55 }
56
57 proc show_diff {path w {lno {}} {scroll_pos {}}} {
58 global file_states file_lists
59 global is_3way_diff diff_active repo_config
60 global ui_diff ui_index ui_workdir
61 global current_diff_path current_diff_side current_diff_header
62
63 if {$diff_active || ![lock_index read]} return
64
65 clear_diff
66 if {$lno == {}} {
67 set lno [lsearch -sorted -exact $file_lists($w) $path]
68 if {$lno >= 0} {
69 incr lno
70 }
71 }
72 if {$lno >= 1} {
73 $w tag add in_diff $lno.0 [expr {$lno + 1}].0
74 }
75
76 set s $file_states($path)
77 set m [lindex $s 0]
78 set is_3way_diff 0
79 set diff_active 1
80 set current_diff_path $path
81 set current_diff_side $w
82 set current_diff_header {}
83 ui_status [mc "Loading diff of %s..." [escape_path $path]]
84
85 # - Git won't give us the diff, there's nothing to compare to!
86 #
87 if {$m eq {_O}} {
88 set max_sz [expr {128 * 1024}]
89 set type unknown
90 if {[catch {
91 set type [file type $path]
92 switch -- $type {
93 directory {
94 set type submodule
95 set content {}
96 set sz 0
97 }
98 link {
99 set content [file readlink $path]
100 set sz [string length $content]
101 }
102 file {
103 set fd [open $path r]
104 fconfigure $fd -eofchar {}
105 set content [read $fd $max_sz]
106 close $fd
107 set sz [file size $path]
108 }
109 default {
110 error "'$type' not supported"
111 }
112 }
113 } err ]} {
114 set diff_active 0
115 unlock_index
116 ui_status [mc "Unable to display %s" [escape_path $path]]
117 error_popup [strcat [mc "Error loading file:"] "\n\n$err"]
118 return
119 }
120 $ui_diff conf -state normal
121 if {$type eq {submodule}} {
122 $ui_diff insert end [append \
123 "* " \
124 [mc "Git Repository (subproject)"] \
125 "\n"] d_@
126 } elseif {![catch {set type [exec file $path]}]} {
127 set n [string length $path]
128 if {[string equal -length $n $path $type]} {
129 set type [string range $type $n end]
130 regsub {^:?\s*} $type {} type
131 }
132 $ui_diff insert end "* $type\n" d_@
133 }
134 if {[string first "\0" $content] != -1} {
135 $ui_diff insert end \
136 [mc "* Binary file (not showing content)."] \
137 d_@
138 } else {
139 if {$sz > $max_sz} {
140 $ui_diff insert end \
141 "* Untracked file is $sz bytes.
142 * Showing only first $max_sz bytes.
143 " d_@
144 }
145 $ui_diff insert end $content
146 if {$sz > $max_sz} {
147 $ui_diff insert end "
148 * Untracked file clipped here by [appname].
149 * To see the entire file, use an external editor.
150 " d_@
151 }
152 }
153 $ui_diff conf -state disabled
154 set diff_active 0
155 unlock_index
156 if {$scroll_pos ne {}} {
157 update
158 $ui_diff yview moveto $scroll_pos
159 }
160 ui_ready
161 return
162 }
163
164 set cmd [list]
165 if {$w eq $ui_index} {
166 lappend cmd diff-index
167 lappend cmd --cached
168 } elseif {$w eq $ui_workdir} {
169 if {[string index $m 0] eq {U}} {
170 lappend cmd diff
171 } else {
172 lappend cmd diff-files
173 }
174 }
175
176 lappend cmd -p
177 lappend cmd --no-color
178 if {$repo_config(gui.diffcontext) >= 1} {
179 lappend cmd "-U$repo_config(gui.diffcontext)"
180 }
181 if {$w eq $ui_index} {
182 lappend cmd [PARENT]
183 }
184 lappend cmd --
185 lappend cmd $path
186
187 if {[catch {set fd [eval git_read --nice $cmd]} err]} {
188 set diff_active 0
189 unlock_index
190 ui_status [mc "Unable to display %s" [escape_path $path]]
191 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
192 return
193 }
194
195 fconfigure $fd \
196 -blocking 0 \
197 -encoding binary \
198 -translation binary
199 fileevent $fd readable [list read_diff $fd $scroll_pos]
200 }
201
202 proc read_diff {fd scroll_pos} {
203 global ui_diff diff_active
204 global is_3way_diff current_diff_header
205
206 $ui_diff conf -state normal
207 while {[gets $fd line] >= 0} {
208 # -- Cleanup uninteresting diff header lines.
209 #
210 if { [string match {diff --git *} $line]
211 || [string match {diff --cc *} $line]
212 || [string match {diff --combined *} $line]
213 || [string match {--- *} $line]
214 || [string match {+++ *} $line]} {
215 append current_diff_header $line "\n"
216 continue
217 }
218 if {[string match {index *} $line]} continue
219 if {$line eq {deleted file mode 120000}} {
220 set line "deleted symlink"
221 }
222
223 # -- Automatically detect if this is a 3 way diff.
224 #
225 if {[string match {@@@ *} $line]} {set is_3way_diff 1}
226
227 if {[string match {mode *} $line]
228 || [string match {new file *} $line]
229 || [regexp {^(old|new) mode *} $line]
230 || [string match {deleted file *} $line]
231 || [string match {deleted symlink} $line]
232 || [string match {Binary files * and * differ} $line]
233 || $line eq {\ No newline at end of file}
234 || [regexp {^\* Unmerged path } $line]} {
235 set tags {}
236 } elseif {$is_3way_diff} {
237 set op [string range $line 0 1]
238 switch -- $op {
239 { } {set tags {}}
240 {@@} {set tags d_@}
241 { +} {set tags d_s+}
242 { -} {set tags d_s-}
243 {+ } {set tags d_+s}
244 {- } {set tags d_-s}
245 {--} {set tags d_--}
246 {++} {
247 if {[regexp {^\+\+([<>]{7} |={7})} $line _g op]} {
248 set line [string replace $line 0 1 { }]
249 set tags d$op
250 } else {
251 set tags d_++
252 }
253 }
254 default {
255 puts "error: Unhandled 3 way diff marker: {$op}"
256 set tags {}
257 }
258 }
259 } else {
260 set op [string index $line 0]
261 switch -- $op {
262 { } {set tags {}}
263 {@} {set tags d_@}
264 {-} {set tags d_-}
265 {+} {
266 if {[regexp {^\+([<>]{7} |={7})} $line _g op]} {
267 set line [string replace $line 0 0 { }]
268 set tags d$op
269 } else {
270 set tags d_+
271 }
272 }
273 default {
274 puts "error: Unhandled 2 way diff marker: {$op}"
275 set tags {}
276 }
277 }
278 }
279 $ui_diff insert end $line $tags
280 if {[string index $line end] eq "\r"} {
281 $ui_diff tag add d_cr {end - 2c}
282 }
283 $ui_diff insert end "\n" $tags
284 }
285 $ui_diff conf -state disabled
286
287 if {[eof $fd]} {
288 close $fd
289 set diff_active 0
290 unlock_index
291 if {$scroll_pos ne {}} {
292 update
293 $ui_diff yview moveto $scroll_pos
294 }
295 ui_ready
296
297 if {[$ui_diff index end] eq {2.0}} {
298 handle_empty_diff
299 }
300 }
301 }
302
303 proc apply_hunk {x y} {
304 global current_diff_path current_diff_header current_diff_side
305 global ui_diff ui_index file_states
306
307 if {$current_diff_path eq {} || $current_diff_header eq {}} return
308 if {![lock_index apply_hunk]} return
309
310 set apply_cmd {apply --cached --whitespace=nowarn}
311 set mi [lindex $file_states($current_diff_path) 0]
312 if {$current_diff_side eq $ui_index} {
313 set failed_msg [mc "Failed to unstage selected hunk."]
314 lappend apply_cmd --reverse
315 if {[string index $mi 0] ne {M}} {
316 unlock_index
317 return
318 }
319 } else {
320 set failed_msg [mc "Failed to stage selected hunk."]
321 if {[string index $mi 1] ne {M}} {
322 unlock_index
323 return
324 }
325 }
326
327 set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
328 set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
329 if {$s_lno eq {}} {
330 unlock_index
331 return
332 }
333
334 set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
335 if {$e_lno eq {}} {
336 set e_lno end
337 }
338
339 if {[catch {
340 set p [eval git_write $apply_cmd]
341 fconfigure $p -translation binary -encoding binary
342 puts -nonewline $p $current_diff_header
343 puts -nonewline $p [$ui_diff get $s_lno $e_lno]
344 close $p} err]} {
345 error_popup [append $failed_msg "\n\n$err"]
346 unlock_index
347 return
348 }
349
350 $ui_diff conf -state normal
351 $ui_diff delete $s_lno $e_lno
352 $ui_diff conf -state disabled
353
354 if {[$ui_diff get 1.0 end] eq "\n"} {
355 set o _
356 } else {
357 set o ?
358 }
359
360 if {$current_diff_side eq $ui_index} {
361 set mi ${o}M
362 } elseif {[string index $mi 0] eq {_}} {
363 set mi M$o
364 } else {
365 set mi ?$o
366 }
367 unlock_index
368 display_file $current_diff_path $mi
369 if {$o eq {_}} {
370 clear_diff
371 } else {
372 set current_diff_path $current_diff_path
373 }
374 }
375
376 proc apply_line {x y} {
377 global current_diff_path current_diff_header current_diff_side
378 global ui_diff ui_index file_states
379
380 if {$current_diff_path eq {} || $current_diff_header eq {}} return
381 if {![lock_index apply_hunk]} return
382
383 set apply_cmd {apply --cached --whitespace=nowarn}
384 set mi [lindex $file_states($current_diff_path) 0]
385 if {$current_diff_side eq $ui_index} {
386 set failed_msg [mc "Failed to unstage selected line."]
387 set to_context {+}
388 lappend apply_cmd --reverse
389 if {[string index $mi 0] ne {M}} {
390 unlock_index
391 return
392 }
393 } else {
394 set failed_msg [mc "Failed to stage selected line."]
395 set to_context {-}
396 if {[string index $mi 1] ne {M}} {
397 unlock_index
398 return
399 }
400 }
401
402 set the_l [$ui_diff index @$x,$y]
403
404 # operate only on change lines
405 set c1 [$ui_diff get "$the_l linestart"]
406 if {$c1 ne {+} && $c1 ne {-}} {
407 unlock_index
408 return
409 }
410 set sign $c1
411
412 set i_l [$ui_diff search -backwards -regexp ^@@ $the_l 0.0]
413 if {$i_l eq {}} {
414 unlock_index
415 return
416 }
417 # $i_l is now at the beginning of a line
418
419 # pick start line number from hunk header
420 set hh [$ui_diff get $i_l "$i_l + 1 lines"]
421 set hh [lindex [split $hh ,] 0]
422 set hln [lindex [split $hh -] 1]
423
424 # There is a special situation to take care of. Consider this hunk:
425 #
426 # @@ -10,4 +10,4 @@
427 # context before
428 # -old 1
429 # -old 2
430 # +new 1
431 # +new 2
432 # context after
433 #
434 # We used to keep the context lines in the order they appear in the
435 # hunk. But then it is not possible to correctly stage only
436 # "-old 1" and "+new 1" - it would result in this staged text:
437 #
438 # context before
439 # old 2
440 # new 1
441 # context after
442 #
443 # (By symmetry it is not possible to *un*stage "old 2" and "new 2".)
444 #
445 # We resolve the problem by introducing an asymmetry, namely, when
446 # a "+" line is *staged*, it is moved in front of the context lines
447 # that are generated from the "-" lines that are immediately before
448 # the "+" block. That is, we construct this patch:
449 #
450 # @@ -10,4 +10,5 @@
451 # context before
452 # +new 1
453 # old 1
454 # old 2
455 # context after
456 #
457 # But we do *not* treat "-" lines that are *un*staged in a special
458 # way.
459 #
460 # With this asymmetry it is possible to stage the change
461 # "old 1" -> "new 1" directly, and to stage the change
462 # "old 2" -> "new 2" by first staging the entire hunk and
463 # then unstaging the change "old 1" -> "new 1".
464
465 # This is non-empty if and only if we are _staging_ changes;
466 # then it accumulates the consecutive "-" lines (after converting
467 # them to context lines) in order to be moved after the "+" change
468 # line.
469 set pre_context {}
470
471 set n 0
472 set i_l [$ui_diff index "$i_l + 1 lines"]
473 set patch {}
474 while {[$ui_diff compare $i_l < "end - 1 chars"] &&
475 [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
476 set next_l [$ui_diff index "$i_l + 1 lines"]
477 set c1 [$ui_diff get $i_l]
478 if {[$ui_diff compare $i_l <= $the_l] &&
479 [$ui_diff compare $the_l < $next_l]} {
480 # the line to stage/unstage
481 set ln [$ui_diff get $i_l $next_l]
482 if {$c1 eq {-}} {
483 set n [expr $n+1]
484 set patch "$patch$pre_context$ln"
485 } else {
486 set patch "$patch$ln$pre_context"
487 }
488 set pre_context {}
489 } elseif {$c1 ne {-} && $c1 ne {+}} {
490 # context line
491 set ln [$ui_diff get $i_l $next_l]
492 set patch "$patch$pre_context$ln"
493 set n [expr $n+1]
494 set pre_context {}
495 } elseif {$c1 eq $to_context} {
496 # turn change line into context line
497 set ln [$ui_diff get "$i_l + 1 chars" $next_l]
498 if {$c1 eq {-}} {
499 set pre_context "$pre_context $ln"
500 } else {
501 set patch "$patch $ln"
502 }
503 set n [expr $n+1]
504 }
505 set i_l $next_l
506 }
507 set patch "@@ -$hln,$n +$hln,[eval expr $n $sign 1] @@\n$patch"
508
509 if {[catch {
510 set p [eval git_write $apply_cmd]
511 fconfigure $p -translation binary -encoding binary
512 puts -nonewline $p $current_diff_header
513 puts -nonewline $p $patch
514 close $p} err]} {
515 error_popup [append $failed_msg "\n\n$err"]
516 }
517
518 unlock_index
519 }