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_@
 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 is_submodule_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 $s 0]
 267         set is_3way_diff 0
 268         set is_submodule_diff 0
 269         set diff_active 1
 270         set current_diff_header {}
 271
 272         set cmd [list]
 273         if {$w eq $ui_index} {
 274                 lappend cmd diff-index
 275                 lappend cmd --cached
 276         } elseif {$w eq $ui_workdir} {
 277                 if {[string first {U} $m] >= 0} {
 278                         lappend cmd diff
 279                 } else {
 280                         lappend cmd diff-files
 281                 }
 282         }
 283         if {![is_config_false gui.textconv] && [git-version >= 1.6.1]} {
 284                 lappend cmd --textconv
 285         }
 286
 287         if {[string match {160000 *} [lindex $s 2]]
 288          || [string match {160000 *} [lindex $s 3]]} {
 289                 set is_submodule_diff 1
 290
 291                 if {[git-version >= "1.6.6"]} {
 292                         lappend cmd --submodule
 293                 }
 294         }
 295
 296         lappend cmd -p
 297         lappend cmd --no-color
 298         if {$repo_config(gui.diffcontext) >= 1} {
 299                 lappend cmd "-U$repo_config(gui.diffcontext)"
 300         }
 301         if {$w eq $ui_index} {
 302                 lappend cmd [PARENT]
 303         }
 304         if {$add_opts ne {}} {
 305                 eval lappend cmd $add_opts
 306         } else {
 307                 lappend cmd --
 308                 lappend cmd $path
 309         }
 310
 311         if {$is_submodule_diff && [git-version < "1.6.6"]} {
 312                 if {$w eq $ui_index} {
 313                         set cmd [list submodule summary --cached -- $path]
 314                 } else {
 315                         set cmd [list submodule summary --files -- $path]
 316                 }
 317         }
 318
 319         if {[catch {set fd [eval git_read --nice $cmd]} err]} {
 320                 set diff_active 0
 321                 unlock_index
 322                 ui_status [mc "Unable to display %s" [escape_path $path]]
 323                 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
 324                 return
 325         }
 326
 327         set ::current_diff_inheader 1
 328         fconfigure $fd \
 329                 -blocking 0 \
 330                 -encoding [get_path_encoding $path] \
 331                 -translation lf
 332         fileevent $fd readable [list read_diff $fd $cont_info]
 333 }
 334
 335 proc read_diff {fd cont_info} {
 336         global ui_diff diff_active is_submodule_diff
 337         global is_3way_diff is_conflict_diff current_diff_header
 338         global current_diff_queue
 339         global diff_empty_count
 340
 341         $ui_diff conf -state normal
 342         while {[gets $fd line] >= 0} {
 343                 # -- Cleanup uninteresting diff header lines.
 344                 #
 345                 if {$::current_diff_inheader} {
 346                         if {   [string match {diff --git *}      $line]
 347                             || [string match {diff --cc *}       $line]
 348                             || [string match {diff --combined *} $line]
 349                             || [string match {--- *}             $line]
 350                             || [string match {+++ *}             $line]} {
 351                                 append current_diff_header $line "\n"
 352                                 continue
 353                         }
 354                 }
 355                 if {[string match {index *} $line]} continue
 356                 if {$line eq {deleted file mode 120000}} {
 357                         set line "deleted symlink"
 358                 }
 359                 set ::current_diff_inheader 0
 360
 361                 # -- Automatically detect if this is a 3 way diff.
 362                 #
 363                 if {[string match {@@@ *} $line]} {set is_3way_diff 1}
 364
 365                 if {[string match {mode *} $line]
 366                         || [string match {new file *} $line]
 367                         || [regexp {^(old|new) mode *} $line]
 368                         || [string match {deleted file *} $line]
 369                         || [string match {deleted symlink} $line]
 370                         || [string match {Binary files * and * differ} $line]
 371                         || $line eq {\ No newline at end of file}
 372                         || [regexp {^\* Unmerged path } $line]} {
 373                         set tags {}
 374                 } elseif {$is_3way_diff} {
 375                         set op [string range $line 0 1]
 376                         switch -- $op {
 377                         {  } {set tags {}}
 378                         {@@} {set tags d_@}
 379                         { +} {set tags d_s+}
 380                         { -} {set tags d_s-}
 381                         {+ } {set tags d_+s}
 382                         {- } {set tags d_-s}
 383                         {--} {set tags d_--}
 384                         {++} {
 385                                 if {[regexp {^\+\+([<>]{7} |={7})} $line _g op]} {
 386                                         set is_conflict_diff 1
 387                                         set line [string replace $line 0 1 {  }]
 388                                         set tags d$op
 389                                 } else {
 390                                         set tags d_++
 391                                 }
 392                         }
 393                         default {
 394                                 puts "error: Unhandled 3 way diff marker: {$op}"
 395                                 set tags {}
 396                         }
 397                         }
 398                 } elseif {$is_submodule_diff} {
 399                         if {$line == ""} continue
 400                         if {[regexp {^Submodule } $line]} {
 401                                 set tags d_@
 402                         } elseif {[regexp {^\* } $line]} {
 403                                 set line [string replace $line 0 1 {Submodule }]
 404                                 set tags d_@
 405                         } else {
 406                                 set op [string range $line 0 2]
 407                                 switch -- $op {
 408                                 {  <} {set tags d_-}
 409                                 {  >} {set tags d_+}
 410                                 {  W} {set tags {}}
 411                                 default {
 412                                         puts "error: Unhandled submodule diff marker: {$op}"
 413                                         set tags {}
 414                                 }
 415                                 }
 416                         }
 417                 } else {
 418                         set op [string index $line 0]
 419                         switch -- $op {
 420                         { } {set tags {}}
 421                         {@} {set tags d_@}
 422                         {-} {set tags d_-}
 423                         {+} {
 424                                 if {[regexp {^\+([<>]{7} |={7})} $line _g op]} {
 425                                         set is_conflict_diff 1
 426                                         set tags d$op
 427                                 } else {
 428                                         set tags d_+
 429                                 }
 430                         }
 431                         default {
 432                                 puts "error: Unhandled 2 way diff marker: {$op}"
 433                                 set tags {}
 434                         }
 435                         }
 436                 }
 437                 $ui_diff insert end $line $tags
 438                 if {[string index $line end] eq "\r"} {
 439                         $ui_diff tag add d_cr {end - 2c}
 440                 }
 441                 $ui_diff insert end "\n" $tags
 442         }
 443         $ui_diff conf -state disabled
 444
 445         if {[eof $fd]} {
 446                 close $fd
 447
 448                 if {$current_diff_queue ne {}} {
 449                         advance_diff_queue $cont_info
 450                         return
 451                 }
 452
 453                 set diff_active 0
 454                 unlock_index
 455                 set scroll_pos [lindex $cont_info 0]
 456                 if {$scroll_pos ne {}} {
 457                         update
 458                         $ui_diff yview moveto $scroll_pos
 459                 }
 460                 ui_ready
 461
 462                 if {[$ui_diff index end] eq {2.0}} {
 463                         handle_empty_diff
 464                 } else {
 465                         set diff_empty_count 0
 466                 }
 467
 468                 set callback [lindex $cont_info 1]
 469                 if {$callback ne {}} {
 470                         eval $callback
 471                 }
 472         }
 473 }
 474
 475 proc apply_hunk {x y} {
 476         global current_diff_path current_diff_header current_diff_side
 477         global ui_diff ui_index file_states
 478
 479         if {$current_diff_path eq {} || $current_diff_header eq {}} return
 480         if {![lock_index apply_hunk]} return
 481
 482         set apply_cmd {apply --cached --whitespace=nowarn}
 483         set mi [lindex $file_states($current_diff_path) 0]
 484         if {$current_diff_side eq $ui_index} {
 485                 set failed_msg [mc "Failed to unstage selected hunk."]
 486                 lappend apply_cmd --reverse
 487                 if {[string index $mi 0] ne {M}} {
 488                         unlock_index
 489                         return
 490                 }
 491         } else {
 492                 set failed_msg [mc "Failed to stage selected hunk."]
 493                 if {[string index $mi 1] ne {M}} {
 494                         unlock_index
 495                         return
 496                 }
 497         }
 498
 499         set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
 500         set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
 501         if {$s_lno eq {}} {
 502                 unlock_index
 503                 return
 504         }
 505
 506         set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
 507         if {$e_lno eq {}} {
 508                 set e_lno end
 509         }
 510
 511         if {[catch {
 512                 set enc [get_path_encoding $current_diff_path]
 513                 set p [eval git_write $apply_cmd]
 514                 fconfigure $p -translation binary -encoding $enc
 515                 puts -nonewline $p $current_diff_header
 516                 puts -nonewline $p [$ui_diff get $s_lno $e_lno]
 517                 close $p} err]} {
 518                 error_popup [append $failed_msg "\n\n$err"]
 519                 unlock_index
 520                 return
 521         }
 522
 523         $ui_diff conf -state normal
 524         $ui_diff delete $s_lno $e_lno
 525         $ui_diff conf -state disabled
 526
 527         if {[$ui_diff get 1.0 end] eq "\n"} {
 528                 set o _
 529         } else {
 530                 set o ?
 531         }
 532
 533         if {$current_diff_side eq $ui_index} {
 534                 set mi ${o}M
 535         } elseif {[string index $mi 0] eq {_}} {
 536                 set mi M$o
 537         } else {
 538                 set mi ?$o
 539         }
 540         unlock_index
 541         display_file $current_diff_path $mi
 542         # This should trigger shift to the next changed file
 543         if {$o eq {_}} {
 544                 reshow_diff
 545         }
 546 }
 547
 548 proc apply_range_or_line {x y} {
 549         global current_diff_path current_diff_header current_diff_side
 550         global ui_diff ui_index file_states
 551
 552         set selected [$ui_diff tag nextrange sel 0.0]
 553
 554         if {$selected == {}} {
 555                 set first [$ui_diff index "@$x,$y"]
 556                 set last $first
 557         } else {
 558                 set first [lindex $selected 0]
 559                 set last [lindex $selected 1]
 560         }
 561
 562         set first_l [$ui_diff index "$first linestart"]
 563         set last_l [$ui_diff index "$last lineend"]
 564
 565         if {$current_diff_path eq {} || $current_diff_header eq {}} return
 566         if {![lock_index apply_hunk]} return
 567
 568         set apply_cmd {apply --cached --whitespace=nowarn}
 569         set mi [lindex $file_states($current_diff_path) 0]
 570         if {$current_diff_side eq $ui_index} {
 571                 set failed_msg [mc "Failed to unstage selected line."]
 572                 set to_context {+}
 573                 lappend apply_cmd --reverse
 574                 if {[string index $mi 0] ne {M}} {
 575                         unlock_index
 576                         return
 577                 }
 578         } else {
 579                 set failed_msg [mc "Failed to stage selected line."]
 580                 set to_context {-}
 581                 if {[string index $mi 1] ne {M}} {
 582                         unlock_index
 583                         return
 584                 }
 585         }
 586
 587         set wholepatch {}
 588
 589         while {$first_l < $last_l} {
 590                 set i_l [$ui_diff search -backwards -regexp ^@@ $first_l 0.0]
 591                 if {$i_l eq {}} {
 592                         # If there's not a @@ above, then the selected range
 593                         # must have come before the first_l @@
 594                         set i_l [$ui_diff search -regexp ^@@ $first_l $last_l]
 595                 }
 596                 if {$i_l eq {}} {
 597                         unlock_index
 598                         return
 599                 }
 600                 # $i_l is now at the beginning of a line
 601
 602                 # pick start line number from hunk header
 603                 set hh [$ui_diff get $i_l "$i_l + 1 lines"]
 604                 set hh [lindex [split $hh ,] 0]
 605                 set hln [lindex [split $hh -] 1]
 606
 607                 # There is a special situation to take care of. Consider this
 608                 # hunk:
 609                 #
 610                 #    @@ -10,4 +10,4 @@
 611                 #     context before
 612                 #    -old 1
 613                 #    -old 2
 614                 #    +new 1
 615                 #    +new 2
 616                 #     context after
 617                 #
 618                 # We used to keep the context lines in the order they appear in
 619                 # the hunk. But then it is not possible to correctly stage only
 620                 # "-old 1" and "+new 1" - it would result in this staged text:
 621                 #
 622                 #    context before
 623                 #    old 2
 624                 #    new 1
 625                 #    context after
 626                 #
 627                 # (By symmetry it is not possible to *un*stage "old 2" and "new
 628                 # 2".)
 629                 #
 630                 # We resolve the problem by introducing an asymmetry, namely,
 631                 # when a "+" line is *staged*, it is moved in front of the
 632                 # context lines that are generated from the "-" lines that are
 633                 # immediately before the "+" block. That is, we construct this
 634                 # patch:
 635                 #
 636                 #    @@ -10,4 +10,5 @@
 637                 #     context before
 638                 #    +new 1
 639                 #     old 1
 640                 #     old 2
 641                 #     context after
 642                 #
 643                 # But we do *not* treat "-" lines that are *un*staged in a
 644                 # special way.
 645                 #
 646                 # With this asymmetry it is possible to stage the change "old
 647                 # 1" -> "new 1" directly, and to stage the change "old 2" ->
 648                 # "new 2" by first staging the entire hunk and then unstaging
 649                 # the change "old 1" -> "new 1".
 650                 #
 651                 # Applying multiple lines adds complexity to the special
 652                 # situation.  The pre_context must be moved after the entire
 653                 # first block of consecutive staged "+" lines, so that
 654                 # staging both additions gives the following patch:
 655                 #
 656                 #    @@ -10,4 +10,6 @@
 657                 #     context before
 658                 #    +new 1
 659                 #    +new 2
 660                 #     old 1
 661                 #     old 2
 662                 #     context after
 663
 664                 # This is non-empty if and only if we are _staging_ changes;
 665                 # then it accumulates the consecutive "-" lines (after
 666                 # converting them to context lines) in order to be moved after
 667                 # "+" change lines.
 668                 set pre_context {}
 669
 670                 set n 0
 671                 set m 0
 672                 set i_l [$ui_diff index "$i_l + 1 lines"]
 673                 set patch {}
 674                 while {[$ui_diff compare $i_l < "end - 1 chars"] &&
 675                        [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
 676                         set next_l [$ui_diff index "$i_l + 1 lines"]
 677                         set c1 [$ui_diff get $i_l]
 678                         if {[$ui_diff compare $first_l <= $i_l] &&
 679                             [$ui_diff compare $i_l < $last_l] &&
 680                             ($c1 eq {-} || $c1 eq {+})} {
 681                                 # a line to stage/unstage
 682                                 set ln [$ui_diff get $i_l $next_l]
 683                                 if {$c1 eq {-}} {
 684                                         set n [expr $n+1]
 685                                         set patch "$patch$pre_context$ln"
 686                                         set pre_context {}
 687                                 } else {
 688                                         set m [expr $m+1]
 689                                         set patch "$patch$ln"
 690                                 }
 691                         } elseif {$c1 ne {-} && $c1 ne {+}} {
 692                                 # context line
 693                                 set ln [$ui_diff get $i_l $next_l]
 694                                 set patch "$patch$pre_context$ln"
 695                                 set n [expr $n+1]
 696                                 set m [expr $m+1]
 697                                 set pre_context {}
 698                         } elseif {$c1 eq $to_context} {
 699                                 # turn change line into context line
 700                                 set ln [$ui_diff get "$i_l + 1 chars" $next_l]
 701                                 if {$c1 eq {-}} {
 702                                         set pre_context "$pre_context $ln"
 703                                 } else {
 704                                         set patch "$patch $ln"
 705                                 }
 706                                 set n [expr $n+1]
 707                                 set m [expr $m+1]
 708                         } else {
 709                                 # a change in the opposite direction of
 710                                 # to_context which is outside the range of
 711                                 # lines to apply.
 712                                 set patch "$patch$pre_context"
 713                                 set pre_context {}
 714                         }
 715                         set i_l $next_l
 716                 }
 717                 set patch "$patch$pre_context"
 718                 set wholepatch "$wholepatch@@ -$hln,$n +$hln,$m @@\n$patch"
 719                 set first_l [$ui_diff index "$next_l + 1 lines"]
 720         }
 721
 722         if {[catch {
 723                 set enc [get_path_encoding $current_diff_path]
 724                 set p [eval git_write $apply_cmd]
 725                 fconfigure $p -translation binary -encoding $enc
 726                 puts -nonewline $p $current_diff_header
 727                 puts -nonewline $p $wholepatch
 728                 close $p} err]} {
 729                 error_popup [append $failed_msg "\n\n$err"]
 730         }
 731
 732         unlock_index
 733 }