gitk: Allow safely calling nukefile from a run queue handler

Originally dorunq assumed that the queue entry remained first
in the queue after the script eval, and blindly removed it.
However, if the handler calls nukefile, it may not be the
case anymore, and a random queue entry gets dropped instead.

This makes dorunq remove the entry before calling the
script, and adds a global variable to allow other functions
to determine if they are called from within a dorunq handler.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

gitk

@@ -22,11 +22,11 @@ proc gitdir {} {
 # run before X event handlers, so reading from a fast source can
 # make the GUI completely unresponsive.
 proc run args {
-    global isonrunq runq
+    global isonrunq runq currunq
 
     set script $args
     if {[info exists isonrunq($script)]} return
-    if {$runq eq {}} {
+    if {$runq eq {} && ![info exists currunq]} {
 	after idle dorunq
     }
     lappend runq [list {} $script]
@@ -38,10 +38,10 @@ proc filerun {fd script} {
 }
 
 proc filereadable {fd script} {
-    global runq
+    global runq currunq
 
     fileevent $fd readable {}
-    if {$runq eq {}} {
+    if {$runq eq {} && ![info exists currunq]} {
 	after idle dorunq
     }
     lappend runq [list $fd $script]
@@ -60,17 +60,19 @@ proc nukefile {fd} {
 }
 
 proc dorunq {} {
-    global isonrunq runq
+    global isonrunq runq currunq
 
     set tstart [clock clicks -milliseconds]
     set t0 $tstart
     while {[llength $runq] > 0} {
 	set fd [lindex $runq 0 0]
 	set script [lindex $runq 0 1]
+	set currunq [lindex $runq 0]
+	set runq [lrange $runq 1 end]
 	set repeat [eval $script]
+	unset currunq
 	set t1 [clock clicks -milliseconds]
 	set t [expr {$t1 - $t0}]
-	set runq [lrange $runq 1 end]
 	if {$repeat ne {} && $repeat} {
 	    if {$fd eq {} || $repeat == 2} {
 		# script returns 1 if it wants to be readded