gitk: Unify handling of merge diffs with normal 2-way diffs

This adds code to getblobdiffline to make it able to recognize and
display merge diffs (i.e. N-way diffs for N >= 3) as well as normal
two-way diffs.  This means that it can also correctly display the
3-way diff of the local changes when the git repository is in the
middle of a merge with conflicts.

This also removes getmergediffline and changes mergediff to invoke
getblobdiffline rather than getmergediffline.

Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/gitk b/gitk
index 3fe1b479b24b93fc1bd17111338cb1a2b746dedd..e6e49fc5cc348a7ea098c36018008a3ddb10e22a 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -2098,7 +2098,7 @@ proc makewindow {} {
     $ctext tag conf filesep -font textfontbold -back "#aaaaaa"
     $ctext tag conf hunksep -fore [lindex $diffcolors 2]
     $ctext tag conf d0 -fore [lindex $diffcolors 0]
-    $ctext tag conf d1 -fore [lindex $diffcolors 1]
+    $ctext tag conf dresult -fore [lindex $diffcolors 1]
     $ctext tag conf m0 -fore red
     $ctext tag conf m1 -fore blue
     $ctext tag conf m2 -fore green
@@ -3217,7 +3217,7 @@ proc find_hunk_blamespec {base line} {
 }
 
 proc external_blame_diff {} {
-    global currentid diffmergeid cmitmode
+    global currentid cmitmode
     global diff_menu_txtpos diff_menu_line
     global diff_menu_filebase flist_menu_file
 
@@ -6668,130 +6668,16 @@ proc mark_ctext_line {lnum} {
 }
 
 proc mergediff {id} {
-    global diffmergeid mdifffd
+    global diffmergeid
     global diffids treediffs
-    global parents
-    global diffcontext
-    global diffencoding
-    global limitdiffs vfilelimit curview
-    global targetline
+    global parents curview
 
     set diffmergeid $id
     set diffids $id
     set treediffs($id) {}
-    set targetline {}
-    # this doesn't seem to actually affect anything...
-    set cmd [concat | git diff-tree --no-commit-id --cc -U$diffcontext $id]
-    if {$limitdiffs && $vfilelimit($curview) ne {}} {
-       set cmd [concat $cmd -- $vfilelimit($curview)]
-    }
-    if {[catch {set mdf [open $cmd r]} err]} {
-       error_popup "[mc "Error getting merge diffs:"] $err"
-       return
-    }
-    fconfigure $mdf -blocking 0 -encoding binary
-    set mdifffd($id) $mdf
     set np [llength $parents($curview,$id)]
-    set diffencoding [get_path_encoding {}]
     settabs $np
-    filerun $mdf [list getmergediffline $mdf $id $np]
-}
-
-proc getmergediffline {mdf id np} {
-    global diffmergeid ctext cflist mergemax
-    global difffilestart mdifffd treediffs
-    global ctext_file_names ctext_file_lines
-    global diffencoding jump_to_here targetline diffline
-
-    $ctext conf -state normal
-    set nr 0
-    while {[incr nr] <= 1000 && [gets $mdf line] >= 0} {
-       if {![info exists diffmergeid] || $id != $diffmergeid
-           || $mdf != $mdifffd($id)} {
-           close $mdf
-           return 0
-       }
-       if {[regexp {^diff --cc (.*)} $line match fname]} {
-           # start of a new file
-           set fname [encoding convertfrom $fname]
-           $ctext insert end "\n"
-           set here [$ctext index "end - 1c"]
-           lappend difffilestart $here
-           lappend treediffs($id) $fname
-           add_flist [list $fname]
-           lappend ctext_file_names $fname
-           lappend ctext_file_lines [lindex [split $here "."] 0]
-           set diffencoding [get_path_encoding $fname]
-           set l [expr {(78 - [string length $fname]) / 2}]
-           set pad [string range "----------------------------------------" 1 $l]
-           $ctext insert end "$pad $fname $pad\n" filesep
-           set targetline {}
-           if {$jump_to_here ne {} && [lindex $jump_to_here 0] eq $fname} {
-               set targetline [lindex $jump_to_here 1]
-           }
-           set diffline 0
-       } elseif {[regexp {^@@} $line]} {
-           set line [encoding convertfrom $diffencoding $line]
-           $ctext insert end "$line\n" hunksep
-           if {[regexp { \+(\d+),\d+ @@} $line m nl]} {
-               set diffline $nl
-           }
-       } elseif {[regexp {^[0-9a-f]{40}$} $line] || [regexp {^index} $line]} {
-           # do nothing
-       } else {
-           set line [encoding convertfrom $diffencoding $line]
-           # parse the prefix - one ' ', '-' or '+' for each parent
-           set spaces {}
-           set minuses {}
-           set pluses {}
-           set isbad 0
-           for {set j 0} {$j < $np} {incr j} {
-               set c [string range $line $j $j]
-               if {$c == " "} {
-                   lappend spaces $j
-               } elseif {$c == "-"} {
-                   lappend minuses $j
-               } elseif {$c == "+"} {
-                   lappend pluses $j
-               } else {
-                   set isbad 1
-                   break
-               }
-           }
-           set tags {}
-           set num {}
-           if {!$isbad && $minuses ne {} && $pluses eq {}} {
-               # line doesn't appear in result, parents in $minuses have the line
-               set num [lindex $minuses 0]
-           } elseif {!$isbad && $pluses ne {} && $minuses eq {}} {
-               # line appears in result, parents in $pluses don't have the line
-               lappend tags mresult
-               set num [lindex $spaces 0]
-           }
-           if {$num ne {}} {
-               if {$num >= $mergemax} {
-                   set num "max"
-               }
-               lappend tags m$num
-           }
-           $ctext insert end "$line\n" $tags
-           if {$targetline ne {} && $minuses eq {}} {
-               if {$diffline == $targetline} {
-                   set here [$ctext index "end - 1 line"]
-                   mark_ctext_line [lindex [split $here .] 0]
-                   set targetline {}
-               } else {
-                   incr diffline
-               }
-           }
-       }
-    }
-    $ctext conf -state disabled
-    if {[eof $mdf]} {
-       close $mdf
-       return 0
-    }
-    return [expr {$nr >= 1000? 2: 1}]
+    getblobdiffs $id
 }
 
 proc startdiff {ids} {
@@ -6971,9 +6857,9 @@ proc getblobdiffs {ids} {
     global diffcontext
     global ignorespace
     global limitdiffs vfilelimit curview
-    global diffencoding targetline
+    global diffencoding targetline diffnparents
 
-    set cmd [diffcmd $ids "-p -C --no-commit-id -U$diffcontext"]
+    set cmd [diffcmd $ids "-p -C --cc --no-commit-id -U$diffcontext"]
     if {$ignorespace} {
        append cmd " -w"
     }
@@ -6981,10 +6867,11 @@ proc getblobdiffs {ids} {
        set cmd [concat $cmd -- $vfilelimit($curview)]
     }
     if {[catch {set bdf [open $cmd r]} err]} {
-       puts "error getting diffs: $err"
+       error_popup [mc "Error getting diffs: %s" $err]
        return
     }
     set targetline {}
+    set diffnparents 0
     set diffinhdr 0
     set diffencoding [get_path_encoding {}]
     fconfigure $bdf -blocking 0 -encoding binary
@@ -7006,9 +6893,11 @@ proc setinlist {var i val} {
 }
 
 proc makediffhdr {fname ids} {
-    global ctext curdiffstart treediffs
+    global ctext curdiffstart treediffs diffencoding
     global ctext_file_names jump_to_here targetline diffline
 
+    set fname [encoding convertfrom $fname]
+    set diffencoding [get_path_encoding $fname]
     set i [lsearch -exact $treediffs($ids) $fname]
     if {$i >= 0} {
        setinlist difffilestart $i $curdiffstart
@@ -7028,7 +6917,7 @@ proc getblobdiffline {bdf ids} {
     global diffids blobdifffd ctext curdiffstart
     global diffnexthead diffnextnote difffilestart
     global ctext_file_names ctext_file_lines
-    global diffinhdr treediffs
+    global diffinhdr treediffs mergemax diffnparents
     global diffencoding jump_to_here targetline diffline
 
     set nr 0
@@ -7038,47 +6927,63 @@ proc getblobdiffline {bdf ids} {
            close $bdf
            return 0
        }
-       if {![string compare -length 11 "diff --git " $line]} {
-           # trim off "diff --git "
-           set line [string range $line 11 end]
-           set diffinhdr 1
+       if {![string compare -length 5 "diff " $line]} {
+           if {![regexp {^diff (--cc|--git) } $line m type]} {
+               set line [encoding convertfrom $line]
+               $ctext insert end "$line\n" hunksep
+               continue
+           }
            # start of a new file
+           set diffinhdr 1
            $ctext insert end "\n"
            set curdiffstart [$ctext index "end - 1c"]
            lappend ctext_file_names ""
            lappend ctext_file_lines [lindex [split $curdiffstart "."] 0]
            $ctext insert end "\n" filesep
-           # If the name hasn't changed the length will be odd,
-           # the middle char will be a space, and the two bits either
-           # side will be a/name and b/name, or "a/name" and "b/name".
-           # If the name has changed we'll get "rename from" and
-           # "rename to" or "copy from" and "copy to" lines following this,
-           # and we'll use them to get the filenames.
-           # This complexity is necessary because spaces in the filename(s)
-           # don't get escaped.
-           set l [string length $line]
-           set i [expr {$l / 2}]
-           if {!(($l & 1) && [string index $line $i] eq " " &&
-                 [string range $line 2 [expr {$i - 1}]] eq \
-                     [string range $line [expr {$i + 3}] end])} {
-               continue
-           }
-           # unescape if quoted and chop off the a/ from the front
-           if {[string index $line 0] eq "\""} {
-               set fname [string range [lindex $line 0] 2 end]
+
+           if {$type eq "--cc"} {
+               # start of a new file in a merge diff
+               set fname [string range $line 10 end]
+               if {[lsearch -exact $treediffs($ids) $fname] < 0} {
+                   lappend treediffs($ids) $fname
+                   add_flist [list $fname]
+               }
+
            } else {
-               set fname [string range $line 2 [expr {$i - 1}]]
+               set line [string range $line 11 end]
+               # If the name hasn't changed the length will be odd,
+               # the middle char will be a space, and the two bits either
+               # side will be a/name and b/name, or "a/name" and "b/name".
+               # If the name has changed we'll get "rename from" and
+               # "rename to" or "copy from" and "copy to" lines following
+               # this, and we'll use them to get the filenames.
+               # This complexity is necessary because spaces in the
+               # filename(s) don't get escaped.
+               set l [string length $line]
+               set i [expr {$l / 2}]
+               if {!(($l & 1) && [string index $line $i] eq " " &&
+                     [string range $line 2 [expr {$i - 1}]] eq \
+                         [string range $line [expr {$i + 3}] end])} {
+                   continue
+               }
+               # unescape if quoted and chop off the a/ from the front
+               if {[string index $line 0] eq "\""} {
+                   set fname [string range [lindex $line 0] 2 end]
+               } else {
+                   set fname [string range $line 2 [expr {$i - 1}]]
+               }
            }
-           set fname [encoding convertfrom $fname]
-           set diffencoding [get_path_encoding $fname]
            makediffhdr $fname $ids
 
-       } elseif {[regexp {^@@ -([0-9]+)(,[0-9]+)? \+([0-9]+)(,[0-9]+)? @@(.*)} \
-                      $line match f1l f1c f2l f2c rest]} {
+       } elseif {![string compare -length 2 "@@" $line]} {
+           regexp {^@@+} $line ats
            set line [encoding convertfrom $diffencoding $line]
            $ctext insert end "$line\n" hunksep
+           if {[regexp { \+(\d+),\d+ @@} $line m nl]} {
+               set diffline $nl
+           }
+           set diffnparents [expr {[string length $ats] - 1}]
            set diffinhdr 0
-           set diffline $f2l
 
        } elseif {$diffinhdr} {
            if {![string compare -length 12 "rename from " $line]} {
@@ -7097,8 +7002,6 @@ proc getblobdiffline {bdf ids} {
                if {[string index $fname 0] eq "\""} {
                    set fname [lindex $fname 0]
                }
-               set fname [encoding convertfrom $fname]
-               set diffencoding [get_path_encoding $fname]
                makediffhdr $fname $ids
            } elseif {[string compare -length 3 $line "---"] == 0} {
                # do nothing
@@ -7111,28 +7014,53 @@ proc getblobdiffline {bdf ids} {
 
        } else {
            set line [encoding convertfrom $diffencoding $line]
-           set x [string range $line 0 0]
-           set here [$ctext index "end - 1 chars"]
-           if {$x == "-" || $x == "+"} {
-               set tag [expr {$x == "+"}]
-               $ctext insert end "$line\n" d$tag
-           } elseif {$x == " "} {
-               $ctext insert end "$line\n"
+           # parse the prefix - one ' ', '-' or '+' for each parent
+           set prefix [string range $line 0 [expr {$diffnparents - 1}]]
+           set tag [expr {$diffnparents > 1? "m": "d"}]
+           if {[string trim $prefix " -+"] eq {}} {
+               # prefix only has " ", "-" and "+" in it: normal diff line
+               set num [string first "-" $prefix]
+               if {$num >= 0} {
+                   # removed line, first parent with line is $num
+                   if {$num >= $mergemax} {
+                       set num "max"
+                   }
+                   $ctext insert end "$line\n" $tag$num
+               } else {
+                   set tags {}
+                   if {[string first "+" $prefix] >= 0} {
+                       # added line
+                       lappend tags ${tag}result
+                       if {$diffnparents > 1} {
+                           set num [string first " " $prefix]
+                           if {$num >= 0} {
+                               if {$num >= $mergemax} {
+                                   set num "max"
+                               }
+                               lappend tags m$num
+                           }
+                       }
+                   }
+                   if {$targetline ne {}} {
+                       if {$diffline == $targetline} {
+                           set seehere [$ctext index "end - 1 chars"]
+                           set targetline {}
+                       } else {
+                           incr diffline
+                       }
+                   }
+                   $ctext insert end "$line\n" $tags
+               }
            } else {
                # "\ No newline at end of file",
                # or something else we don't recognize
                $ctext insert end "$line\n" hunksep
            }
-           if {$targetline ne {} && ($x eq " " || $x eq "+")} {
-               if {$diffline == $targetline} {
-                   mark_ctext_line [lindex [split $here .] 0]
-                   set targetline {}
-               } else {
-                   incr diffline
-               }
-           }
        }
     }
+    if {[info exists seehere]} {
+       mark_ctext_line [lindex [split $seehere .] 0]
+    }
     $ctext conf -state disabled
     if {[eof $bdf]} {
        close $bdf
@@ -7145,7 +7073,7 @@ proc changediffdisp {} {
     global ctext diffelide
 
     $ctext tag conf d0 -elide [lindex $diffelide 0]
-    $ctext tag conf d1 -elide [lindex $diffelide 1]
+    $ctext tag conf dresult -elide [lindex $diffelide 1]
 }
 
 proc highlightfile {loc cline} {
@@ -9817,7 +9745,7 @@ proc doprefs {} {
     label $top.diffnew -padx 40 -relief sunk -background [lindex $diffcolors 1]
     button $top.diffnewbut -text [mc "Diff: new lines"] -font optionfont \
        -command [list choosecolor diffcolors 1 $top.diffnew "diff new lines" \
-                     [list $ctext tag conf d1 -foreground]]
+                     [list $ctext tag conf dresult -foreground]]
     grid x $top.diffnewbut $top.diffnew -sticky w
     label $top.hunksep -padx 40 -relief sunk -background [lindex $diffcolors 2]
     button $top.hunksepbut -text [mc "Diff: hunk header"] -font optionfont \