gitk: Some improvements for the code for updating the display

This should be more robust in the case that some does "Update" before
the initial drawing is finished.  It also avoids having to reset the
list of children for each commit and reconstruct it.

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

gitk

@@ -133,14 +133,6 @@ proc getcommitlines {commfd}  {
 	set id [lindex $ids 0]
 	set olds [lrange $ids 1 end]
 	set cmit [string range $cmit [expr {$j + 1}] end]
-	if {$phase == "updatecommits"} {
-	    $canv delete all
-	    set oldcommits $commits
-	    set commits {}
-	    unset children
-	    unset nchildren
-	    set phase getcommits
-	}
 	lappend commits $id
 	set commitlisted($id) 1
 	parsecommit $id $cmit 1 [lrange $ids 1 end]
@@ -751,7 +743,6 @@ proc assigncolor {id} {
 
 proc initgraph {} {
     global canvy canvy0 lineno numcommits nextcolor linespc
-    global mainline mainlinearrow sidelines
     global nchildren ncleft
     global displist nhyperspace
 
@@ -760,9 +751,11 @@ proc initgraph {} {
     set canvy $canvy0
     set lineno -1
     set numcommits 0
-    catch {unset mainline}
-    catch {unset mainlinearrow}
-    catch {unset sidelines}
+    foreach v {mainline mainlinearrow sidelines colormap cornercrossings
+		crossings idline lineid} {
+	global $v
+	catch {unset $v}
+    }
     foreach id [array names nchildren] {
 	set ncleft($id) $nchildren($id)
     }
@@ -1431,30 +1424,23 @@ proc decidenext {{noread 0}} {
 	    }
 	}
     }
-    if {$level < 0} {
-	if {$todo != {}} {
-	    puts "ERROR: none of the pending commits can be done yet:"
-	    foreach p $todo {
-		puts "  $p ($ncleft($p))"
-	    }
-	}
-	return -1
-    }
 
     return $level
 }
 
 proc drawcommit {id reading} {
-    global phase todo nchildren datemode nextupdate revlistorder
-    global numcommits ncmupdate displayorder todo onscreen
+    global phase todo nchildren datemode nextupdate revlistorder ncleft
     global numcommits ncmupdate displayorder todo onscreen parents
+    global commitlisted commitordered
 
     if {$phase != "incrdraw"} {
 	set phase incrdraw
 	set displayorder {}
 	set todo {}
 	initgraph
+	catch {unset commitordered}
     }
+    set commitordered($id) 1
     if {$nchildren($id) == 0} {
 	lappend todo $id
 	set onscreen($id) 0
@@ -1469,18 +1455,16 @@ proc drawcommit {id reading} {
 	updatetodo $level 0
     } else {
 	set level [decidenext 1]
-	if {$level == {} || $id != [lindex $todo $level]} {
-	    return
-	}
+	if {$level == {} || $level < 0} return
 	while 1 {
+	    set id [lindex $todo $level]
+	    if {![info exists commitordered($id)]} {
+		break
+	    }
 	    lappend displayorder [lindex $todo $level]
 	    if {[updatetodo $level $datemode]} {
 		set level [decidenext 1]
-		if {$level == {}} break
-	    }
-	    set id [lindex $todo $level]
-	    if {![info exists commitlisted($id)]} {
-		break
+		if {$level == {} || $level < 0} break
 	    }
 	}
     }
@@ -1490,17 +1474,19 @@ proc drawcommit {id reading} {
 proc finishcommits {} {
     global phase oldcommits commits
     global canv mainfont ctext maincursor textcursor
-    global parents
+    global parents displayorder todo
 
     if {$phase == "incrdraw" || $phase == "removecommits"} {
 	foreach id $oldcommits {
 	    lappend commits $id
-	    updatechildren $id $parents($id)
 	    drawcommit $id 0
 	}
 	set oldcommits {}
 	drawrest
     } elseif {$phase == "updatecommits"} {
+	# there were no new commits, in fact
+	set commits $oldcommits
+	set oldcommits {}
 	set phase {}
     } else {
 	$canv delete all
@@ -1540,7 +1526,7 @@ proc drawgraph {} {
 
 proc drawrest {} {
     global phase stopped redisplaying selectedline
-    global datemode todo displayorder
+    global datemode todo displayorder ncleft
     global numcommits ncmupdate
     global nextupdate startmsecs revlistorder
 
@@ -1556,6 +1542,13 @@ proc drawrest {} {
 	    }
 	}
     }
+    if {$todo != {}} {
+	puts "ERROR: none of the pending commits can be done yet:"
+	foreach p $todo {
+	    puts "  $p ($ncleft($p))"
+	}
+    }
+
     drawmore 0
     set phase {}
     set drawmsecs [expr {[clock clicks -milliseconds] - $startmsecs}]
@@ -3637,13 +3630,35 @@ proc updatecommits {rargs} {
     global idtags idheads idotherrefs
     global leftover
     global parsed_args
-    global canv
+    global canv mainfont
     global oldcommits commits
     global parents nchildren children ncleft
 
     set old_args $parsed_args
     parse_args $rargs
 
+    if {$phase == "getcommits" || $phase == "incrdraw"} {
+	# havent read all the old commits, just start again from scratch
+	stopfindproc
+	set oldcommits {}
+	set commits {}
+	foreach v {children nchildren parents commitlisted commitinfo
+		   selectedline matchinglines treediffs
+		   mergefilelist currentid rowtextx} {
+	    global $v
+	    catch {unset $v}
+	}
+	readrefs
+	if {$phase == "incrdraw"} {
+	    allcanvs delete all
+	    $canv create text 3 3 -anchor nw -text "Reading commits..." \
+		-font $mainfont -tags textitems
+	    set phase getcommits
+	}
+	start_rev_list $parsed_args
+	return
+    }
+
     foreach id $old_args {
 	if {![regexp {^[0-9a-f]{40}$} $id]} continue
 	if {[info exists oldref($id)]} continue
@@ -3664,20 +3679,27 @@ proc updatecommits {rargs} {
     }
 
     set phase updatecommits
+    set oldcommits $commits
+    set commits {}
     set removed_commits [split [eval exec git-rev-list $ignorenew] "\n" ]
     if {[llength $removed_commits] > 0} {
-	$canv delete all
-	set oldcommits {}
-	foreach c $commits {
-	    if {[lsearch $c $removed_commits] < 0} {
-		lappend oldcommits $c
-	    } else {
+	allcanvs delete all
+	foreach c $removed_commits {
+	    set i [lsearch -exact $oldcommits $c]
+	    if {$i >= 0} {
+		set oldcommits [lreplace $oldcommits $i $i]
 		unset commitlisted($c)
+		foreach p $parents($c) {
+		    if {[info exists nchildren($p)]} {
+			set j [lsearch -exact $children($p) $c]
+			if {$j >= 0} {
+			    set children($p) [lreplace $children($p) $j $j]
+			    incr nchildren($p) -1
+			}
+		    }
+		}
 	    }
 	}
-	set commits {}
-	unset children
-	unset nchildren
 	set phase removecommits
     }