git-gui / lib / diff.tclon commit Merge branch 'nd/index-doc' into maint (094574b)
   1# git-gui diff viewer
   2# Copyright (C) 2006, 2007 Shawn Pearce
   3
   4proc 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
  19proc 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 $after
  40        }
  41}
  42
  43proc force_diff_encoding {enc} {
  44        global current_diff_path
  45        
  46        if {$current_diff_path ne {}} {
  47                force_path_encoding $current_diff_path $enc
  48                reshow_diff
  49        }
  50}
  51
  52proc 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
  68The modification date of this file was updated by another application, but the content within the file was not changed.
  69
  70A 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 $path __
  74        rescan ui_ready 0
  75}
  76
  77proc show_diff {path w {lno {}} {scroll_pos {}} {callback {}}} {
  78        global file_states file_lists
  79        global is_3way_diff is_conflict_diff diff_active repo_config
  80        global ui_diff ui_index ui_workdir
  81        global current_diff_path current_diff_side current_diff_header
  82        global current_diff_queue
  83
  84        if {$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 $cont_info
 114        }
 115}
 116
 117proc show_unmerged_diff {cont_info} {
 118        global current_diff_path current_diff_side
 119        global merge_stages ui_diff is_conflict_diff
 120        global current_diff_queue
 121
 122        if {$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
 150proc 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 $item 2]
 161}
 162
 163proc show_other_diff {path w m cont_info} {
 164        global file_states file_lists
 165        global is_3way_diff diff_active repo_config
 166        global ui_diff ui_index ui_workdir
 167        global current_diff_path current_diff_side current_diff_header
 168
 169        # - Git won't give us the diff, there's nothing to compare to!
 170        #
 171        if {$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
 256proc 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 $s 3]]} {
 289                set is_submodule_diff 1
 290
 291                if {[git-version >= "1.6.6"]} {
 292                        lappend cmd --submodule
 293                }
 294        }
 295
 296        lappend cmd -p
 297        lappend cmd --color
 298        if {$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
 335proc parse_color_line {line} {
 336        set start 0
 337        set result ""
 338        set markup [list]
 339        set regexp {\033\[((?:\d+;)*\d+)?m}
 340        while {[regexp -indices -start $start $regexp $line match code]} {
 341                foreach {begin end} $match break
 342                append result [string range $line $start [expr {$begin - 1}]]
 343                lappend markup [string length $result] \
 344                        [eval [linsert $code 0 string range $line]]
 345                set start [incr end]
 346        }
 347        append result [string range $line $start end]
 348        if {[llength $markup] < 4} {set markup {}}
 349        return [list $result $markup]
 350}
 351
 352proc read_diff {fd cont_info} {
 353        global ui_diff diff_active is_submodule_diff
 354        global is_3way_diff is_conflict_diff current_diff_header
 355        global current_diff_queue
 356        global diff_empty_count
 357
 358        $ui_diff conf -state normal
 359        while {[gets $fd line] >= 0} {
 360                foreach {line markup} [parse_color_line $line] break
 361                set line [string map {\033 ^} $line]
 362
 363                # -- Cleanup uninteresting diff header lines.
 364                #
 365                if {$::current_diff_inheader} {
 366                        if {   [string match {diff --git *}      $line]
 367                            || [string match {diff --cc *}       $line]
 368                            || [string match {diff --combined *} $line]
 369                            || [string match {--- *}             $line]
 370                            || [string match {+++ *}             $line]} {
 371                                append current_diff_header $line "\n"
 372                                continue
 373                        }
 374                }
 375                if {[string match {index *} $line]} continue
 376                if {$line eq {deleted file mode 120000}} {
 377                        set line "deleted symlink"
 378                }
 379                set ::current_diff_inheader 0
 380
 381                # -- Automatically detect if this is a 3 way diff.
 382                #
 383                if {[string match {@@@ *} $line]} {set is_3way_diff 1}
 384
 385                if {[string match {mode *} $line]
 386                        || [string match {new file *} $line]
 387                        || [regexp {^(old|new) mode *} $line]
 388                        || [string match {deleted file *} $line]
 389                        || [string match {deleted symlink} $line]
 390                        || [string match {Binary files * and * differ} $line]
 391                        || $line eq {\ No newline at end of file}
 392                        || [regexp {^\* Unmerged path } $line]} {
 393                        set tags {}
 394                } elseif {$is_3way_diff} {
 395                        set op [string range $line 0 1]
 396                        switch -- $op {
 397                        {  } {set tags {}}
 398                        {@@} {set tags d_@}
 399                        { +} {set tags d_s+}
 400                        { -} {set tags d_s-}
 401                        {+ } {set tags d_+s}
 402                        {- } {set tags d_-s}
 403                        {--} {set tags d_--}
 404                        {++} {
 405                                if {[regexp {^\+\+([<>]{7} |={7})} $line _g op]} {
 406                                        set is_conflict_diff 1
 407                                        set line [string replace $line 0 1 {  }]
 408                                        set tags d$op
 409                                } else {
 410                                        set tags d_++
 411                                }
 412                        }
 413                        default {
 414                                puts "error: Unhandled 3 way diff marker: {$op}"
 415                                set tags {}
 416                        }
 417                        }
 418                } elseif {$is_submodule_diff} {
 419                        if {$line == ""} continue
 420                        if {[regexp {^Submodule } $line]} {
 421                                set tags d_@
 422                        } elseif {[regexp {^\* } $line]} {
 423                                set line [string replace $line 0 1 {Submodule }]
 424                                set tags d_@
 425                        } else {
 426                                set op [string range $line 0 2]
 427                                switch -- $op {
 428                                {  <} {set tags d_-}
 429                                {  >} {set tags d_+}
 430                                {  W} {set tags {}}
 431                                default {
 432                                        puts "error: Unhandled submodule diff marker: {$op}"
 433                                        set tags {}
 434                                }
 435                                }
 436                        }
 437                } else {
 438                        set op [string index $line 0]
 439                        switch -- $op {
 440                        { } {set tags {}}
 441                        {@} {set tags d_@}
 442                        {-} {set tags d_-}
 443                        {+} {
 444                                if {[regexp {^\+([<>]{7} |={7})} $line _g op]} {
 445                                        set is_conflict_diff 1
 446                                        set tags d$op
 447                                } else {
 448                                        set tags d_+
 449                                }
 450                        }
 451                        default {
 452                                puts "error: Unhandled 2 way diff marker: {$op}"
 453                                set tags {}
 454                        }
 455                        }
 456                }
 457                set mark [$ui_diff index "end - 1 line linestart"]
 458                $ui_diff insert end $line $tags
 459                if {[string index $line end] eq "\r"} {
 460                        $ui_diff tag add d_cr {end - 2c}
 461                }
 462                $ui_diff insert end "\n" $tags
 463
 464                foreach {posbegin colbegin posend colend} $markup {
 465                        set prefix clr
 466                        foreach style [split $colbegin ";"] {
 467                                if {$style eq "7"} {append prefix i; continue}
 468                                if {$style < 30 || $style > 47} {continue}
 469                                set a "$mark linestart + $posbegin chars"
 470                                set b "$mark linestart + $posend chars"
 471                                catch {$ui_diff tag add $prefix$style $a $b}
 472                        }
 473                }
 474        }
 475        $ui_diff conf -state disabled
 476
 477        if {[eof $fd]} {
 478                close $fd
 479
 480                if {$current_diff_queue ne {}} {
 481                        advance_diff_queue $cont_info
 482                        return
 483                }
 484
 485                set diff_active 0
 486                unlock_index
 487                set scroll_pos [lindex $cont_info 0]
 488                if {$scroll_pos ne {}} {
 489                        update
 490                        $ui_diff yview moveto $scroll_pos
 491                }
 492                ui_ready
 493
 494                if {[$ui_diff index end] eq {2.0}} {
 495                        handle_empty_diff
 496                } else {
 497                        set diff_empty_count 0
 498                }
 499
 500                set callback [lindex $cont_info 1]
 501                if {$callback ne {}} {
 502                        eval $callback
 503                }
 504        }
 505}
 506
 507proc apply_hunk {x y} {
 508        global current_diff_path current_diff_header current_diff_side
 509        global ui_diff ui_index file_states
 510
 511        if {$current_diff_path eq {} || $current_diff_header eq {}} return
 512        if {![lock_index apply_hunk]} return
 513
 514        set apply_cmd {apply --cached --whitespace=nowarn}
 515        set mi [lindex $file_states($current_diff_path) 0]
 516        if {$current_diff_side eq $ui_index} {
 517                set failed_msg [mc "Failed to unstage selected hunk."]
 518                lappend apply_cmd --reverse
 519                if {[string index $mi 0] ne {M}} {
 520                        unlock_index
 521                        return
 522                }
 523        } else {
 524                set failed_msg [mc "Failed to stage selected hunk."]
 525                if {[string index $mi 1] ne {M}} {
 526                        unlock_index
 527                        return
 528                }
 529        }
 530
 531        set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
 532        set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
 533        if {$s_lno eq {}} {
 534                unlock_index
 535                return
 536        }
 537
 538        set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
 539        if {$e_lno eq {}} {
 540                set e_lno end
 541        }
 542
 543        if {[catch {
 544                set enc [get_path_encoding $current_diff_path]
 545                set p [eval git_write $apply_cmd]
 546                fconfigure $p -translation binary -encoding $enc
 547                puts -nonewline $p $current_diff_header
 548                puts -nonewline $p [$ui_diff get $s_lno $e_lno]
 549                close $p} err]} {
 550                error_popup [append $failed_msg "\n\n$err"]
 551                unlock_index
 552                return
 553        }
 554
 555        $ui_diff conf -state normal
 556        $ui_diff delete $s_lno $e_lno
 557        $ui_diff conf -state disabled
 558
 559        if {[$ui_diff get 1.0 end] eq "\n"} {
 560                set o _
 561        } else {
 562                set o ?
 563        }
 564
 565        if {$current_diff_side eq $ui_index} {
 566                set mi ${o}M
 567        } elseif {[string index $mi 0] eq {_}} {
 568                set mi M$o
 569        } else {
 570                set mi ?$o
 571        }
 572        unlock_index
 573        display_file $current_diff_path $mi
 574        # This should trigger shift to the next changed file
 575        if {$o eq {_}} {
 576                reshow_diff
 577        }
 578}
 579
 580proc apply_range_or_line {x y} {
 581        global current_diff_path current_diff_header current_diff_side
 582        global ui_diff ui_index file_states
 583
 584        set selected [$ui_diff tag nextrange sel 0.0]
 585
 586        if {$selected == {}} {
 587                set first [$ui_diff index "@$x,$y"]
 588                set last $first
 589        } else {
 590                set first [lindex $selected 0]
 591                set last [lindex $selected 1]
 592        }
 593
 594        set first_l [$ui_diff index "$first linestart"]
 595        set last_l [$ui_diff index "$last lineend"]
 596
 597        if {$current_diff_path eq {} || $current_diff_header eq {}} return
 598        if {![lock_index apply_hunk]} return
 599
 600        set apply_cmd {apply --cached --whitespace=nowarn}
 601        set mi [lindex $file_states($current_diff_path) 0]
 602        if {$current_diff_side eq $ui_index} {
 603                set failed_msg [mc "Failed to unstage selected line."]
 604                set to_context {+}
 605                lappend apply_cmd --reverse
 606                if {[string index $mi 0] ne {M}} {
 607                        unlock_index
 608                        return
 609                }
 610        } else {
 611                set failed_msg [mc "Failed to stage selected line."]
 612                set to_context {-}
 613                if {[string index $mi 1] ne {M}} {
 614                        unlock_index
 615                        return
 616                }
 617        }
 618
 619        set wholepatch {}
 620
 621        while {$first_l < $last_l} {
 622                set i_l [$ui_diff search -backwards -regexp ^@@ $first_l 0.0]
 623                if {$i_l eq {}} {
 624                        # If there's not a @@ above, then the selected range
 625                        # must have come before the first_l @@
 626                        set i_l [$ui_diff search -regexp ^@@ $first_l $last_l]
 627                }
 628                if {$i_l eq {}} {
 629                        unlock_index
 630                        return
 631                }
 632                # $i_l is now at the beginning of a line
 633
 634                # pick start line number from hunk header
 635                set hh [$ui_diff get $i_l "$i_l + 1 lines"]
 636                set hh [lindex [split $hh ,] 0]
 637                set hln [lindex [split $hh -] 1]
 638
 639                # There is a special situation to take care of. Consider this
 640                # hunk:
 641                #
 642                #    @@ -10,4 +10,4 @@
 643                #     context before
 644                #    -old 1
 645                #    -old 2
 646                #    +new 1
 647                #    +new 2
 648                #     context after
 649                #
 650                # We used to keep the context lines in the order they appear in
 651                # the hunk. But then it is not possible to correctly stage only
 652                # "-old 1" and "+new 1" - it would result in this staged text:
 653                #
 654                #    context before
 655                #    old 2
 656                #    new 1
 657                #    context after
 658                #
 659                # (By symmetry it is not possible to *un*stage "old 2" and "new
 660                # 2".)
 661                #
 662                # We resolve the problem by introducing an asymmetry, namely,
 663                # when a "+" line is *staged*, it is moved in front of the
 664                # context lines that are generated from the "-" lines that are
 665                # immediately before the "+" block. That is, we construct this
 666                # patch:
 667                #
 668                #    @@ -10,4 +10,5 @@
 669                #     context before
 670                #    +new 1
 671                #     old 1
 672                #     old 2
 673                #     context after
 674                #
 675                # But we do *not* treat "-" lines that are *un*staged in a
 676                # special way.
 677                #
 678                # With this asymmetry it is possible to stage the change "old
 679                # 1" -> "new 1" directly, and to stage the change "old 2" ->
 680                # "new 2" by first staging the entire hunk and then unstaging
 681                # the change "old 1" -> "new 1".
 682                #
 683                # Applying multiple lines adds complexity to the special
 684                # situation.  The pre_context must be moved after the entire
 685                # first block of consecutive staged "+" lines, so that
 686                # staging both additions gives the following patch:
 687                #
 688                #    @@ -10,4 +10,6 @@
 689                #     context before
 690                #    +new 1
 691                #    +new 2
 692                #     old 1
 693                #     old 2
 694                #     context after
 695
 696                # This is non-empty if and only if we are _staging_ changes;
 697                # then it accumulates the consecutive "-" lines (after
 698                # converting them to context lines) in order to be moved after
 699                # "+" change lines.
 700                set pre_context {}
 701
 702                set n 0
 703                set m 0
 704                set i_l [$ui_diff index "$i_l + 1 lines"]
 705                set patch {}
 706                while {[$ui_diff compare $i_l < "end - 1 chars"] &&
 707                       [$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
 708                        set next_l [$ui_diff index "$i_l + 1 lines"]
 709                        set c1 [$ui_diff get $i_l]
 710                        if {[$ui_diff compare $first_l <= $i_l] &&
 711                            [$ui_diff compare $i_l < $last_l] &&
 712                            ($c1 eq {-} || $c1 eq {+})} {
 713                                # a line to stage/unstage
 714                                set ln [$ui_diff get $i_l $next_l]
 715                                if {$c1 eq {-}} {
 716                                        set n [expr $n+1]
 717                                        set patch "$patch$pre_context$ln"
 718                                        set pre_context {}
 719                                } else {
 720                                        set m [expr $m+1]
 721                                        set patch "$patch$ln"
 722                                }
 723                        } elseif {$c1 ne {-} && $c1 ne {+}} {
 724                                # context line
 725                                set ln [$ui_diff get $i_l $next_l]
 726                                set patch "$patch$pre_context$ln"
 727                                set n [expr $n+1]
 728                                set m [expr $m+1]
 729                                set pre_context {}
 730                        } elseif {$c1 eq $to_context} {
 731                                # turn change line into context line
 732                                set ln [$ui_diff get "$i_l + 1 chars" $next_l]
 733                                if {$c1 eq {-}} {
 734                                        set pre_context "$pre_context $ln"
 735                                } else {
 736                                        set patch "$patch $ln"
 737                                }
 738                                set n [expr $n+1]
 739                                set m [expr $m+1]
 740                        } else {
 741                                # a change in the opposite direction of
 742                                # to_context which is outside the range of
 743                                # lines to apply.
 744                                set patch "$patch$pre_context"
 745                                set pre_context {}
 746                        }
 747                        set i_l $next_l
 748                }
 749                set patch "$patch$pre_context"
 750                set wholepatch "$wholepatch@@ -$hln,$n +$hln,$m @@\n$patch"
 751                set first_l [$ui_diff index "$next_l + 1 lines"]
 752        }
 753
 754        if {[catch {
 755                set enc [get_path_encoding $current_diff_path]
 756                set p [eval git_write $apply_cmd]
 757                fconfigure $p -translation binary -encoding $enc
 758                puts -nonewline $p $current_diff_header
 759                puts -nonewline $p $wholepatch
 760                close $p} err]} {
 761                error_popup [append $failed_msg "\n\n$err"]
 762        }
 763
 764        unlock_index
 765}