gitk: Support showing the gathered inline diffs

The previous commit split the diffs into a separate field.  Now we
actually want to show them.

To that end we use the stored diff, and

- process it once to build a fake "tree diff", i.e., a list of all
  changed files;

- feed it through parseblobdiffline to actually format it into the
  $ctext field, like the existing diff machinery would.
Signed-off-by: NThomas Rast <trast@inf.ethz.ch>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

gitk

@@ -156,10 +156,12 @@ proc unmerged_files {files} {
 
 proc parseviewargs {n arglist} {
     global vdatemode vmergeonly vflags vdflags vrevs vfiltered vorigargs env
+    global vinlinediff
     global worddiff git_version
 
     set vdatemode($n) 0
     set vmergeonly($n) 0
+    set vinlinediff($n) 0
     set glflags {}
     set diffargs {}
     set nextisval 0
@@ -7131,6 +7133,7 @@ proc selectline {l isnew {desired_loc {}}} {
     global cmitmode showneartags allcommits
     global targetrow targetid lastscrollrows
     global autoselect autosellen jump_to_here
+    global vinlinediff
 
     catch {unset pending_select}
     $canv delete hover
@@ -7272,6 +7275,8 @@ proc selectline {l isnew {desired_loc {}}} {
     init_flist [mc "Comments"]
     if {$cmitmode eq "tree"} {
 	gettree $id
+    } elseif {$vinlinediff($curview) == 1} {
+	showinlinediff $id
     } elseif {[llength $olds] <= 1} {
 	startdiff $id
     } else {
@@ -7608,6 +7613,39 @@ proc startdiff {ids} {
     }
 }
 
+proc showinlinediff {ids} {
+    global commitinfo commitdata ctext
+    global treediffs
+
+    set info $commitinfo($ids)
+    set diff [lindex $info 7]
+    set difflines [split $diff "\n"]
+
+    initblobdiffvars
+    set treediff {}
+
+    set inhdr 0
+    foreach line $difflines {
+	if {![string compare -length 5 "diff " $line]} {
+	    set inhdr 1
+	} elseif {$inhdr && ![string compare -length 4 "+++ " $line]} {
+	    # offset also accounts for the b/ prefix
+	    lappend treediff [string range $line 6 end]
+	    set inhdr 0
+	}
+    }
+
+    set treediffs($ids) $treediff
+    add_flist $treediff
+
+    $ctext conf -state normal
+    foreach line $difflines {
+	parseblobdiffline $ids $line
+    }
+    maybe_scroll_ctext 1
+    $ctext conf -state disabled
+}
+
 # If the filename (name) is under any of the passed filter paths
 # then return true to include the file in the listing.
 proc path_filter {filter name} {