[RFC 2/4] gitk: Add diff-diff support

[Steffen Prohaska <prohaska@zib.de>]

---
 gitk-git/gitk |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/gitk-git/gitk b/gitk-git/gitk
index 1da0b0a..ca121e4 100644
--- a/gitk-git/gitk
+++ b/gitk-git/gitk
@@ -1019,6 +1019,8 @@ proc makewindow {} {
 	-command {diffvssel 0}
     $rowctxmenu add command -label "Diff selected -> this" \
 	-command {diffvssel 1}
+    $rowctxmenu add command -label "Diff Diff selected -> this" \
+	-command {diffdiffvssel 1}
     $rowctxmenu add command -label "Make patch" -command mkpatch
     $rowctxmenu add command -label "Create tag" -command mktag
     $rowctxmenu add command -label "Write commit to file" -command writecommit
@@ -6010,6 +6012,50 @@ proc doseldiff {oldid newid} {
     startdiff [list $oldid $newid]
 }
 
+proc diffdiffvssel {dirn} {
+    global rowmenuid selectedline displayorder
+
+    if {![info exists selectedline]} return
+    if {$dirn} {
+	set oldid [lindex $displayorder $selectedline]
+	set newid $rowmenuid
+    } else {
+	set oldid $rowmenuid
+	set newid [lindex $displayorder $selectedline]
+    }
+    addtohistory [list doseldiffdiff $oldid $newid]
+    doseldiffdiff $oldid $newid
+}
+
+proc doseldiffdiff {oldid newid} {
+    global ctext
+    global commitinfo
+
+    $ctext conf -state normal
+    clear_ctext
+    init_flist "Top"
+    $ctext insert end "From Commit "
+    $ctext insert end $oldid link0
+    setlink $oldid link0
+    $ctext insert end "\n     "
+    $ctext insert end [lindex $commitinfo($oldid) 0]
+    $ctext insert end "\n\nTo Commit   "
+    $ctext insert end $newid link1
+    setlink $newid link1
+    $ctext insert end "\n     "
+    $ctext insert end [lindex $commitinfo($newid) 0]
+    $ctext insert end "\n"
+    $ctext insert end "\n"
+    $ctext conf -state disabled
+    $ctext tag remove found 1.0 end
+
+    set diff [exec git diff-diff $oldid $newid]
+    $ctext conf -state normal
+    $ctext insert end "\n"
+    $ctext insert end $diff
+    $ctext conf -state disabled
+}
+
 proc mkpatch {} {
     global rowmenuid currentid commitinfo patchtop patchnum
 
-- 
1.5.4.rc0.37.geff3a-dirty