git-gui/lib/diff.tcl

   1 # git-gui diff viewer
   2 # Copyright (C) 2006, 2007 Shawn Pearce
   3
   4 proc apply_tab_size {{firsttab {}}} {
   5         global have_tk85 repo_config ui_diff
   6
   7         set w [font measure font_diff "0"]
   8         if {$have_tk85 && $firsttab != 0} {
   9                 $ui_diff configure -tabs [list [expr {$firsttab * $w}] [expr {($firsttab + $repo_config(gui.tabsize)) * $w}]]
  10         } elseif {$have_tk85 || $repo_config(gui.tabsize) != 8} {
  11                 $ui_diff configure -tabs [expr {$repo_config(gui.tabsize) * $w}]
  12         } else {
  13                 $ui_diff configure -tabs {}
  14         }
  15 }
  16
  17 proc clear_diff {} {
  18         global ui_diff current_diff_path current_diff_header
  19         global ui_index ui_workdir
  20
  21         $ui_diff conf -state normal
  22         $ui_diff delete 0.0 end
  23         $ui_diff conf -state disabled
  24
  25         set current_diff_path {}
  26         set current_diff_header {}
  27
  28         $ui_index tag remove in_diff 0.0 end
  29         $ui_workdir tag remove in_diff 0.0 end
  30 }
  31
  32 proc reshow_diff {{after {}}} {
  33         global file_states file_lists
  34         global current_diff_path current_diff_side
  35         global ui_diff
  36
  37         set p $current_diff_path
  38         if {$p eq {}} {
  39                 # No diff is being shown.
  40         } elseif {$current_diff_side eq {}} {
  41                 clear_diff
  42         } elseif {[catch {set s $file_states($p)}]
  43                 || [lsearch -sorted -exact $file_lists($current_diff_side) $p] == -1} {
  44
  45                 if {[find_next_diff $current_diff_side $p {} {[^O]}]} {
  46                         next_diff $after
  47                 } else {
  48                         clear_diff
  49                 }
  50         } else {
  51                 set save_pos [lindex [$ui_diff yview] 0]
  52                 show_diff $p $current_diff_side {} $save_pos $after
  53         }
  54 }
  55
  56 proc force_diff_encoding {enc} {
  57         global current_diff_path
  58
  59         if {$current_diff_path ne {}} {
  60                 force_path_encoding $current_diff_path $enc
  61                 reshow_diff
  62         }
  63 }
  64
  65 proc handle_empty_diff {} {
  66         global current_diff_path file_states file_lists
  67         global diff_empty_count
  68
  69         set path $current_diff_path
  70         set s $file_states($path)
  71         if {[lindex $s 0] ne {_M} || [has_textconv $path]} return
  72
  73         # Prevent infinite rescan loops
  74         incr diff_empty_count
  75         if {$diff_empty_count > 1} return
  76
  77         info_popup [mc "No differences detected.
  78
  79 %s has no changes.
  80
  81 The modification date of this file was updated by another application, but the content within the file was not changed.
  82
  83 A rescan will be automatically started to find other files which may have the same state." [short_path $path]]
  84
  85         clear_diff
  86         display_file $path __
  87         rescan ui_ready 0
  88 }
  89
  90 proc show_diff {path w {lno {}} {scroll_pos {}} {callback {}}} {
  91         global file_states file_lists
  92         global is_3way_diff is_conflict_diff diff_active repo_config
  93         global ui_diff ui_index ui_workdir
  94         global current_diff_path current_diff_side current_diff_header
  95         global current_diff_queue
  96
  97         if {$diff_active || ![lock_index read]} return
  98
  99         clear_diff
 100         if {$lno == {}} {
 101                 set lno [lsearch -sorted -exact $file_lists($w) $path]
 102                 if {$lno >= 0} {
 103                         incr lno
 104                 }
 105         }
 106         if {$lno >= 1} {
 107                 $w tag add in_diff $lno.0 [expr {$lno + 1}].0
 108                 $w see $lno.0
 109         }
 110
 111         set s $file_states($path)
 112         set m [lindex $s 0]
 113         set is_conflict_diff 0
 114         set current_diff_path $path
 115         set current_diff_side $w
 116         set current_diff_queue {}
 117         ui_status [mc "Loading diff of %s..." [escape_path $path]]
 118
 119         set cont_info [list $scroll_pos $callback]
 120
 121         apply_tab_size 0
 122
 123         if {[string first {U} $m] >= 0} {
 124                 merge_load_stages $path [list show_unmerged_diff $cont_info]
 125         } elseif {$m eq {_O}} {
 126                 show_other_diff $path $w $m $cont_info
 127         } else {
 128                 start_show_diff $cont_info
 129         }
 130
 131         global current_diff_path selected_paths
 132         set selected_paths($current_diff_path) 1
 133 }
 134
 135 proc show_unmerged_diff {cont_info} {
 136         global current_diff_path current_diff_side
 137         global merge_stages ui_diff is_conflict_diff
 138         global current_diff_queue
 139
 140         if {$merge_stages(2) eq {}} {
 141                 set is_conflict_diff 1
 142                 lappend current_diff_queue \
 143                         [list [mc "LOCAL: deleted\nREMOTE:\n"] d= \
 144                             [list ":1:$current_diff_path" ":3:$current_diff_path"]]
 145         } elseif {$merge_stages(3) eq {}} {
 146                 set is_conflict_diff 1
 147                 lappend current_diff_queue \
 148                         [list [mc "REMOTE: deleted\nLOCAL:\n"] d= \
 149                             [list ":1:$current_diff_path" ":2:$current_diff_path"]]
 150         } elseif {[lindex $merge_stages(1) 0] eq {120000}
 151                 || [lindex $merge_stages(2) 0] eq {120000}
 152                 || [lindex $merge_stages(3) 0] eq {120000}} {
 153                 set is_conflict_diff 1
 154                 lappend current_diff_queue \
 155                         [list [mc "LOCAL:\n"] d= \
 156                             [list ":1:$current_diff_path" ":2:$current_diff_path"]]
 157                 lappend current_diff_queue \
 158                         [list [mc "REMOTE:\n"] d= \
 159                             [list ":1:$current_diff_path" ":3:$current_diff_path"]]
 160         } else {
 161                 start_show_diff $cont_info
 162                 return
 163         }
 164
 165         advance_diff_queue $cont_info
 166 }
 167
 168 proc advance_diff_queue {cont_info} {
 169         global current_diff_queue ui_diff
 170
 171         set item [lindex $current_diff_queue 0]
 172         set current_diff_queue [lrange $current_diff_queue 1 end]
 173
 174         $ui_diff conf -state normal
 175         $ui_diff insert end [lindex $item 0] [lindex $item 1]
 176         $ui_diff conf -state disabled
 177
 178         start_show_diff $cont_info [lindex $item 2]
 179 }
 180
 181 proc show_other_diff {path w m cont_info} {
 182         global file_states file_lists
 183         global is_3way_diff diff_active repo_config
 184         global ui_diff ui_index ui_workdir
 185         global current_diff_path current_diff_side current_diff_header
 186
 187         # - Git won't give us the diff, there's nothing to compare to!
 188         #
 189         if {$m eq {_O}} {
 190                 set max_sz 100000
 191                 set type unknown
 192                 if {[catch {
 193                                 set type [file type $path]
 194                                 switch -- $type {
 195                                 directory {
 196                                         set type submodule
 197                                         set content {}
 198                                         set sz 0
 199                                 }
 200                                 link {
 201                                         set content [file readlink $path]
 202                                         set sz [string length $content]
 203                                 }
 204                                 file {
 205                                         set fd [open $path r]
 206                                         fconfigure $fd \
 207                                                 -eofchar {} \
 208                                                 -encoding [get_path_encoding $path]
 209                                         set content [read $fd $max_sz]
 210                                         close $fd
 211                                         set sz [file size $path]
 212                                 }
 213                                 default {
 214                                         error "'$type' not supported"
 215                                 }
 216                                 }
 217                         } err ]} {
 218                         set diff_active 0
 219                         unlock_index
 220                         ui_status [mc "Unable to display %s" [escape_path $path]]
 221                         error_popup [strcat [mc "Error loading file:"] "\n\n$err"]
 222                         return
 223                 }
 224                 $ui_diff conf -state normal
 225                 if {$type eq {submodule}} {
 226                         $ui_diff insert end \
 227                                 "* [mc "Git Repository (subproject)"]\n" \
 228                                 d_info
 229                 } elseif {![catch {set type [exec file $path]}]} {
 230                         set n [string length $path]
 231                         if {[string equal -length $n $path $type]} {
 232                                 set type [string range $type $n end]
 233                                 regsub {^:?\s*} $type {} type
 234                         }
 235                         $ui_diff insert end "* $type\n" d_info
 236                 }
 237                 if {[string first "\0" $content] != -1} {
 238                         $ui_diff insert end \
 239                                 [mc "* Binary file (not showing content)."] \
 240                                 d_info
 241                 } else {
 242                         if {$sz > $max_sz} {
 243                                 $ui_diff insert end [mc \
 244 "* Untracked file is %d bytes.
 245 * Showing only first %d bytes.
 246 " $sz $max_sz] d_info
 247                         }
 248                         $ui_diff insert end $content
 249                         if {$sz > $max_sz} {
 250                                 $ui_diff insert end [mc "
 251 * Untracked file clipped here by %s.
 252 * To see the entire file, use an external editor.
 253 " [appname]] d_info
 254                         }
 255                 }
 256                 $ui_diff conf -state disabled
 257                 set diff_active 0
 258                 unlock_index
 259                 set scroll_pos [lindex $cont_info 0]
 260                 if {$scroll_pos ne {}} {
 261                         update
 262                         $ui_diff yview moveto $scroll_pos
 263                 }
 264                 ui_ready
 265                 set callback [lindex $cont_info 1]
 266                 if {$callback ne {}} {
 267                         eval $callback
 268                 }
 269                 return
 270         }
 271 }
 272
 273 proc get_conflict_marker_size {path} {
 274         set size 7
 275         catch {
 276                 set fd_rc [eval [list git_read check-attr "conflict-marker-size" -- $path]]
 277                 set ret [gets $fd_rc line]
 278                 close $fd_rc
 279                 if {$ret > 0} {
 280                         regexp {.*: conflict-marker-size: (\d+)$} $line line size
 281                 }
 282         }
 283         return $size
 284 }
 285
 286 proc start_show_diff {cont_info {add_opts {}}} {
 287         global file_states file_lists
 288         global is_3way_diff is_submodule_diff diff_active repo_config
 289         global ui_diff ui_index ui_workdir
 290         global current_diff_path current_diff_side current_diff_header
 291
 292         set path $current_diff_path
 293         set w $current_diff_side
 294
 295         set s $file_states($path)
 296         set m [lindex $s 0]
 297         set is_3way_diff 0
 298         set is_submodule_diff 0
 299         set diff_active 1
 300         set current_diff_header {}
 301         set conflict_size [get_conflict_marker_size $path]
 302
 303         set cmd [list]
 304         if {$w eq $ui_index} {
 305                 lappend cmd diff-index
 306                 lappend cmd --cached
 307                 if {[git-version >= "1.7.2"]} {
 308                         lappend cmd --ignore-submodules=dirty
 309                 }
 310         } elseif {$w eq $ui_workdir} {
 311                 if {[string first {U} $m] >= 0} {
 312                         lappend cmd diff
 313                 } else {
 314                         lappend cmd diff-files
 315                 }
 316         }
 317         if {![is_config_false gui.textconv] && [git-version >= 1.6.1]} {
 318                 lappend cmd --textconv
 319         }
 320
 321         if {[string match {160000 *} [lindex $s 2]]
 322          || [string match {160000 *} [lindex $s 3]]} {
 323                 set is_submodule_diff 1
 324
 325                 if {[git-version >= "1.6.6"]} {
 326                         lappend cmd --submodule
 327                 }
 328         }
 329
 330         lappend cmd -p
 331         lappend cmd --color
 332         set cmd [concat $cmd $repo_config(gui.diffopts)]
 333         if {$repo_config(gui.diffcontext) >= 1} {
 334                 lappend cmd "-U$repo_config(gui.diffcontext)"
 335         }
 336         if {$w eq $ui_index} {
 337                 lappend cmd [PARENT]
 338         }
 339         if {$add_opts ne {}} {
 340                 eval lappend cmd $add_opts
 341         } else {
 342                 lappend cmd --
 343                 lappend cmd $path
 344         }
 345
 346         if {$is_submodule_diff && [git-version < "1.6.6"]} {
 347                 if {$w eq $ui_index} {
 348                         set cmd [list submodule summary --cached -- $path]
 349                 } else {
 350                         set cmd [list submodule summary --files -- $path]
 351                 }
 352         }
 353
 354         if {[catch {set fd [eval git_read --nice $cmd]} err]} {
 355                 set diff_active 0
 356                 unlock_index
 357                 ui_status [mc "Unable to display %s" [escape_path $path]]
 358                 error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
 359                 return
 360         }
 361
 362         set ::current_diff_inheader 1
 363         fconfigure $fd \
 364                 -blocking 0 \
 365                 -encoding [get_path_encoding $path] \
 366                 -translation lf
 367         fileevent $fd readable [list read_diff $fd $conflict_size $cont_info]
 368 }
 369
 370 proc parse_color_line {line} {
 371         set start 0
 372         set result ""
 373         set markup [list]
 374         set regexp {\033\[((?:\d+;)*\d+)?m}
 375         set need_reset 0
 376         while {[regexp -indices -start $start $regexp $line match code]} {
 377                 foreach {begin end} $match break
 378                 append result [string range $line $start [expr {$begin - 1}]]
 379                 set pos [string length $result]
 380                 set col [eval [linsert $code 0 string range $line]]
 381                 set start [incr end]
 382                 if {$col eq "0" || $col eq ""} {
 383                         if {!$need_reset} continue
 384                         set need_reset 0
 385                 } else {
 386                         set need_reset 1
 387                 }
 388                 lappend markup $pos $col
 389         }
 390         append result [string range $line $start end]
 391         if {[llength $markup] < 4} {set markup {}}
 392         return [list $result $markup]
 393 }
 394
 395 proc read_diff {fd conflict_size cont_info} {
 396         global ui_diff diff_active is_submodule_diff
 397         global is_3way_diff is_conflict_diff current_diff_header
 398         global current_diff_queue
 399         global diff_empty_count
 400
 401         $ui_diff conf -state normal
 402         while {[gets $fd line] >= 0} {
 403                 foreach {line markup} [parse_color_line $line] break
 404                 set line [string map {\033 ^} $line]
 405
 406                 set tags {}
 407
 408                 # -- Check for start of diff header.
 409                 if {   [string match {diff --git *}      $line]
 410                     || [string match {diff --cc *}       $line]
 411                     || [string match {diff --combined *} $line]} {
 412                         set ::current_diff_inheader 1
 413                 }
 414
 415                 # -- Check for end of diff header (any hunk line will do this).
 416                 #
 417                 if {[regexp {^@@+ } $line]} {set ::current_diff_inheader 0}
 418
 419                 # -- Automatically detect if this is a 3 way diff.
 420                 #
 421                 if {[string match {@@@ *} $line]} {
 422                         set is_3way_diff 1
 423                         apply_tab_size 1
 424                 }
 425
 426                 if {$::current_diff_inheader} {
 427
 428                         # -- These two lines stop a diff header and shouldn't be in there
 429                         if {   [string match {Binary files * and * differ} $line]
 430                             || [regexp {^\* Unmerged path }                $line]} {
 431                                 set ::current_diff_inheader 0
 432                         } else {
 433                                 append current_diff_header $line "\n"
 434                         }
 435
 436                         # -- Cleanup uninteresting diff header lines.
 437                         #
 438                         if {   [string match {diff --git *}      $line]
 439                             || [string match {diff --cc *}       $line]
 440                             || [string match {diff --combined *} $line]
 441                             || [string match {--- *}             $line]
 442                             || [string match {+++ *}             $line]
 443                             || [string match {index *}           $line]} {
 444                                 continue
 445                         }
 446
 447                         # -- Name it symlink, not 120000
 448                         #    Note, that the original line is in $current_diff_header
 449                         regsub {^(deleted|new) file mode 120000} $line {\1 symlink} line
 450
 451                 } elseif {   $line eq {\ No newline at end of file}} {
 452                         # -- Handle some special lines
 453                 } elseif {$is_3way_diff} {
 454                         set op [string range $line 0 1]
 455                         switch -- $op {
 456                         {  } {set tags {}}
 457                         {@@} {set tags d_@}
 458                         { +} {set tags d_s+}
 459                         { -} {set tags d_s-}
 460                         {+ } {set tags d_+s}
 461                         {- } {set tags d_-s}
 462                         {--} {set tags d_--}
 463                         {++} {
 464                                 set regexp [string map [list %conflict_size $conflict_size]\
 465                                                                 {^\+\+([<>=]){%conflict_size}(?: |$)}]
 466                                 if {[regexp $regexp $line _g op]} {
 467                                         set is_conflict_diff 1
 468                                         set line [string replace $line 0 1 {  }]
 469                                         set tags d$op
 470                                 } else {
 471                                         set tags d_++
 472                                 }
 473                         }
 474                         default {
 475                                 puts "error: Unhandled 3 way diff marker: {$op}"
 476                                 set tags {}
 477                         }
 478                         }
 479                 } elseif {$is_submodule_diff} {
 480                         if {$line == ""} continue
 481                         if {[regexp {^Submodule } $line]} {
 482                                 set tags d_info
 483                         } elseif {[regexp {^\* } $line]} {
 484                                 set line [string replace $line 0 1 {Submodule }]
 485                                 set tags d_info
 486                         } else {
 487                                 set op [string range $line 0 2]
 488                                 switch -- $op {
 489                                 {  <} {set tags d_-}
 490                                 {  >} {set tags d_+}
 491                                 {  W} {set tags {}}
 492                                 default {
 493                                         puts "error: Unhandled submodule diff marker: {$op}"
 494                                         set tags {}
 495                                 }
 496                                 }
 497                         }
 498                 } else {
 499                         set op [string index $line 0]
 500                         switch -- $op {
 501                         { } {set tags {}}
 502                         {@} {set tags d_@}
 503                         {-} {set tags d_-}
 504                         {+} {
 505                                 set regexp [string map [list %conflict_size $conflict_size]\
 506                                                                 {^\+([<>=]){%conflict_size}(?: |$)}]
 507                                 if {[regexp $regexp $line _g op]} {
 508                                         set is_conflict_diff 1
 509                                         set tags d$op
 510                                 } else {
 511                                         set tags d_+
 512                                 }
 513                         }
 514                         default {
 515                                 puts "error: Unhandled 2 way diff marker: {$op}"
 516                                 set tags {}
 517                         }
 518                         }
 519                 }
 520                 set mark [$ui_diff index "end - 1 line linestart"]
 521                 $ui_diff insert end $line $tags
 522                 if {[string index $line end] eq "\r"} {
 523                         $ui_diff tag add d_cr {end - 2c}
 524                 }
 525                 $ui_diff insert end "\n" $tags
 526
 527                 foreach {posbegin colbegin posend colend} $markup {
 528                         set prefix clr
 529                         foreach style [lsort -integer [split $colbegin ";"]] {
 530                                 if {$style eq "7"} {append prefix i; continue}
 531                                 if {$style != 4 && ($style < 30 || $style > 47)} {continue}
 532                                 set a "$mark linestart + $posbegin chars"
 533                                 set b "$mark linestart + $posend chars"
 534                                 catch {$ui_diff tag add $prefix$style $a $b}
 535                         }
 536                 }
 537         }
 538         $ui_diff conf -state disabled
 539
 540         if {[eof $fd]} {
 541                 close $fd
 542
 543                 if {$current_diff_queue ne {}} {
 544                         advance_diff_queue $cont_info
 545                         return
 546                 }
 547
 548                 set diff_active 0
 549                 unlock_index
 550                 set scroll_pos [lindex $cont_info 0]
 551                 if {$scroll_pos ne {}} {
 552                         update
 553                         $ui_diff yview moveto $scroll_pos
 554                 }
 555                 ui_ready
 556
 557                 if {[$ui_diff index end] eq {2.0}} {
 558                         handle_empty_diff
 559                 } else {
 560                         set diff_empty_count 0
 561                 }
 562
 563                 set callback [lindex $cont_info 1]
 564                 if {$callback ne {}} {
 565                         eval $callback
 566                 }
 567         }
 568 }
 569
 570 proc apply_or_revert_hunk {x y revert} {
 571         global current_diff_path current_diff_header current_diff_side
 572         global ui_diff ui_index file_states last_revert last_revert_enc
 573
 574         if {$current_diff_path eq {} || $current_diff_header eq {}} return
 575         if {![lock_index apply_hunk]} return
 576
 577         set apply_cmd {apply --whitespace=nowarn}
 578         set mi [lindex $file_states($current_diff_path) 0]
 579         if {$current_diff_side eq $ui_index} {
 580                 set failed_msg [mc "Failed to unstage selected hunk."]
 581                 lappend apply_cmd --reverse --cached
 582                 if {[string index $mi 0] ne {M}} {
 583                         unlock_index
 584                         return
 585                 }
 586         } else {
 587                 if {$revert} {
 588                         set failed_msg [mc "Failed to revert selected hunk."]
 589                         lappend apply_cmd --reverse
 590                 } else {
 591                         set failed_msg [mc "Failed to stage selected hunk."]
 592                         lappend apply_cmd --cached
 593                 }
 594
 595                 if {[string index $mi 1] ne {M}} {
 596                         unlock_index
 597                         return
 598                 }
 599         }
 600
 601         set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
 602         set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
 603         if {$s_lno eq {}} {
 604                 unlock_index
 605                 return
 606         }
 607
 608         set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
 609         if {$e_lno eq {}} {
 610                 set e_lno end
 611         }
 612
 613         set wholepatch "$current_diff_header[$ui_diff get $s_lno $e_lno]"
 614
 615         if {[catch {
 616                 set enc [get_path_encoding $current_diff_path]
 617                 set p [eval git_write $apply_cmd]
 618                 fconfigure $p -translation binary -encoding $enc
 619                 puts -nonewline $p $wholepatch
 620                 close $p} err]} {
 621                 error_popup "$failed_msg\n\n$err"
 622                 unlock_index
 623                 return
 624         }
 625
 626         if {$revert} {
 627                 # Save a copy of this patch for undoing reverts.
 628                 set last_revert $wholepatch
 629                 set last_revert_enc $enc
 630         }
 631
 632         $ui_diff conf -state normal
 633         $ui_diff delete $s_lno $e_lno
 634         $ui_diff conf -state disabled
 635
 636         # Check if the hunk was the last one in the file.
 637         if {[$ui_diff get 1.0 end] eq "\n"} {
 638                 set o _
 639         } else {
 640                 set o ?
 641         }
 642
 643         # Update the status flags.
 644         if {$revert} {
 645                 set mi [string index $mi 0]$o
 646         } elseif {$current_diff_side eq $ui_index} {
 647                 set mi ${o}M
 648         } elseif {[string index $mi 0] eq {_}} {
 649                 set mi M$o
 650         } else {
 651                 set mi ?$o
 652         }
 653         unlock_index
 654         display_file $current_diff_path $mi
 655         # This should trigger shift to the next changed file
 656         if {$o eq {_}} {
 657                 reshow_diff
 658         }
 659 }
 660
 661 proc apply_or_revert_range_or_line {x y revert} {
 662         global current_diff_path current_diff_header current_diff_side
 663         global ui_diff ui_index file_states last_revert
 664
 665         set selected [$ui_diff tag nextrange sel 0.0]
 666
 667         if {$selected == {}} {
 668                 set first [$ui_diff index "@$x,$y"]
 669                 set last $first
 670         } else {
 671                 set first [lindex $selected 0]
 672                 set last [lindex $selected 1]
 673         }
 674
 675         set first_l [$ui_diff index "$first linestart"]
 676         set last_l [$ui_diff index "$last lineend"]
 677
 678         if {$current_diff_path eq {} || $current_diff_header eq {}} return
 679         if {![lock_index apply_hunk]} return
 680
 681         set apply_cmd {apply --whitespace=nowarn}
 682         set mi [lindex $file_states($current_diff_path) 0]
 683         if {$current_diff_side eq $ui_index} {
 684                 set failed_msg [mc "Failed to unstage selected line."]
 685                 set to_context {+}
 686                 lappend apply_cmd --reverse --cached
 687                 if {[string index $mi 0] ne {M}} {
 688                         unlock_index
 689                         return
 690                 }
 691         } else {
 692                 if {$revert} {
 693                         set failed_msg [mc "Failed to revert selected line."]
 694                         set to_context {+}
 695                         lappend apply_cmd --reverse
 696                 } else {
 697                         set failed_msg [mc "Failed to stage selected line."]
 698                         set to_context {-}
 699                         lappend apply_cmd --cached
 700                 }
 701
 702                 if {[string index $mi 1] ne {M}} {
 703                         unlock_index
 704                         return
 705                 }
 706         }
 707
 708         set wholepatch {}
 709
 710         while {$first_l < $last_l} {
 711                 set i_l [$ui_diff search -backwards -regexp ^@@ $first_l 0.0]
 712                 if {$i_l eq {}} {
 713                         # If there's not a @@ above, then the selected range
 714                         # must have come before the first_l @@
 715                         set i_l [$ui_diff search -regexp ^@@ $first_l $last_l]
 716                 }
 717                 if {$i_l eq {}} {
 718                         unlock_index
 719                         return
 720                 }
 721                 # $i_l is now at the beginning of a line
 722
 723                 # pick start line number from hunk header
 724                 set hh [$ui_diff get $i_l "$i_l + 1 lines"]
 725                 set hh [lindex [split $hh ,] 0]
 726                 set hln [lindex [split $hh -] 1]
 727                 set hln [lindex [split $hln " "] 0]
 728
 729                 # There is a special situation to take care of. Consider this
 730                 # hunk:
 731                 #
 732                 #    @@ -10,4 +10,4 @@
 733                 #     context before
 734                 #    -old 1
 735                 #    -old 2
 736                 #    +new 1
 737                 #    +new 2
 738                 #     context after
 739                 #
 740                 # We used to keep the context lines in the order they appear in
 741                 # the hunk. But then it is not possible to correctly stage only
 742                 # "-old 1" and "+new 1" - it would result in this staged text:
 743                 #
 744                 #    context before
 745                 #    old 2
 746                 #    new 1
 747                 #    context after
 748                 #
 749                 # (By symmetry it is not possible to *un*stage "old 2" and "new
 750                 # 2".)
 751                 #
 752                 # We resolve the problem by introducing an asymmetry, namely,
 753                 # when a "+" line is *staged*, it is moved in front of the
 754                 # context lines that are generated from the "-" lines that are
 755                 # immediately before the "+" block. That is, we construct this
 756                 # patch:
 757                 #
 758                 #    @@ -10,4 +10,5 @@
 759                 #     context before
 760                 #    +new 1
 761                 #     old 1
 762                 #     old 2
 763                 #     context after
 764                 #
 765                 # But we do *not* treat "-" lines that are *un*staged in a
 766                 # special way.
 767                 #
 768                 # With this asymmetry it is possible to stage the change "old
 769                 # 1" -> "new 1" directly, and to stage the change "old 2" ->
 770                 # "new 2" by first staging the entire hunk and then unstaging
 771                 # the change "old 1" -> "new 1".
 772                 #
 773                 # Applying multiple lines adds complexity to the special
 774                 # situation.  The pre_context must be moved after the entire
 775                 # first block of consecutive staged "+" lines, so that
 776                 # staging both additions gives the following patch:
 777                 #
 778                 #    @@ -10,4 +10,6 @@
 779                 #     context before
 780                 #    +new 1
 781                 #    +new 2
 782                 #     old 1
 783                 #     old 2
 784                 #     context after
 785
 786                 # This is non-empty if and only if we are _staging_ changes;
 787                 # then it accumulates the consecutive "-" lines (after
 788                 # converting them to context lines) in order to be moved after
 789                 # "+" change lines.
 790                 set pre_context {}
 791
 792                 set n 0
 793                 set m 0
 794                 set i_l [$ui_diff index "$i_l + 1 lines"]
 795                 set patch {}
 796                 while {[$ui_diff compare $i_l < "end - 1 chars"] &&
 797                        [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
 798                         set next_l [$ui_diff index "$i_l + 1 lines"]
 799                         set c1 [$ui_diff get $i_l]
 800                         if {[$ui_diff compare $first_l <= $i_l] &&
 801                             [$ui_diff compare $i_l < $last_l] &&
 802                             ($c1 eq {-} || $c1 eq {+})} {
 803                                 # a line to stage/unstage
 804                                 set ln [$ui_diff get $i_l $next_l]
 805                                 if {$c1 eq {-}} {
 806                                         set n [expr $n+1]
 807                                         set patch "$patch$pre_context$ln"
 808                                         set pre_context {}
 809                                 } else {
 810                                         set m [expr $m+1]
 811                                         set patch "$patch$ln"
 812                                 }
 813                         } elseif {$c1 ne {-} && $c1 ne {+}} {
 814                                 # context line
 815                                 set ln [$ui_diff get $i_l $next_l]
 816                                 set patch "$patch$pre_context$ln"
 817                                 # Skip the "\ No newline at end of
 818                                 # file". Depending on the locale setting
 819                                 # we don't know what this line looks
 820                                 # like exactly. The only thing we do
 821                                 # know is that it starts with "\ "
 822                                 if {![string match {\\ *} $ln]} {
 823                                         set n [expr $n+1]
 824                                         set m [expr $m+1]
 825                                 }
 826                                 set pre_context {}
 827                         } elseif {$c1 eq $to_context} {
 828                                 # turn change line into context line
 829                                 set ln [$ui_diff get "$i_l + 1 chars" $next_l]
 830                                 if {$c1 eq {-}} {
 831                                         set pre_context "$pre_context $ln"
 832                                 } else {
 833                                         set patch "$patch $ln"
 834                                 }
 835                                 set n [expr $n+1]
 836                                 set m [expr $m+1]
 837                         } else {
 838                                 # a change in the opposite direction of
 839                                 # to_context which is outside the range of
 840                                 # lines to apply.
 841                                 set patch "$patch$pre_context"
 842                                 set pre_context {}
 843                         }
 844                         set i_l $next_l
 845                 }
 846                 set patch "$patch$pre_context"
 847                 set wholepatch "$wholepatch@@ -$hln,$n +$hln,$m @@\n$patch"
 848                 set first_l [$ui_diff index "$next_l + 1 lines"]
 849         }
 850
 851         if {[catch {
 852                 set enc [get_path_encoding $current_diff_path]
 853                 set p [eval git_write $apply_cmd]
 854                 fconfigure $p -translation binary -encoding $enc
 855                 puts -nonewline $p $current_diff_header
 856                 puts -nonewline $p $wholepatch
 857                 close $p} err]} {
 858                 error_popup "$failed_msg\n\n$err"
 859                 unlock_index
 860                 return
 861         }
 862
 863         if {$revert} {
 864                 # Save a copy of this patch for undoing reverts.
 865                 set last_revert $current_diff_header$wholepatch
 866                 set last_revert_enc $enc
 867         }
 868
 869         unlock_index
 870 }
 871
 872 # Undo the last line/hunk reverted. When hunks and lines are reverted, a copy
 873 # of the diff applied is saved. Re-apply that diff to undo the revert.
 874 #
 875 # Right now, we only use a single variable to hold the copy, and not a
 876 # stack/deque for simplicity, so multiple undos are not possible. Maybe this
 877 # can be added if the need for something like this is felt in the future.
 878 proc undo_last_revert {} {
 879         global last_revert current_diff_path current_diff_header
 880         global last_revert_enc
 881
 882         if {$last_revert eq {}} return
 883         if {![lock_index apply_hunk]} return
 884
 885         set apply_cmd {apply --whitespace=nowarn}
 886         set failed_msg [mc "Failed to undo last revert."]
 887
 888         if {[catch {
 889                 set enc $last_revert_enc
 890                 set p [eval git_write $apply_cmd]
 891                 fconfigure $p -translation binary -encoding $enc
 892                 puts -nonewline $p $last_revert
 893                 close $p} err]} {
 894                 error_popup "$failed_msg\n\n$err"
 895                 unlock_index
 896                 return
 897         }
 898
 899         set last_revert {}
 900
 901         unlock_index
 902 }