[PATCH 2/3] gitk: write only changed configuration variables

[Max Kirillov <max@max630.net>]

If a variable is changed in a concurrent gitk or manually it is
preserved unless it has changed in this instance

This change does not affect geometry and views save; geometry does not
need it, and views need special merging, which treats each view
separately rather that fully replace the shole list.

Signed-off-by: Max Kirillov <max@max630.net>
---
 gitk | 41 +++++++++++++++++++++++++++++++++--------
 1 file changed, 33 insertions(+), 8 deletions(-)

diff --git a/gitk b/gitk
index 6069afe..6e22024 100755
--- a/gitk
+++ b/gitk
@@ -2804,12 +2804,25 @@ proc doprogupdate {} {
     }
 }
 
+proc config_variable_change_cb {name name2 op} {
+    global config_variable_changed
+    if {$op eq "write"} {
+	set config_variable_changed($name) 1
+    }
+}
+
 proc savestuff {w} {
-    global viewname viewfiles viewargs viewargscmd viewperm nextviewnum
-    global use_ttk
     global stuffsaved
     global config_file config_file_tmp
-    global config_variables
+    global config_variables config_variable_changed
+
+    upvar #0 viewname current_viewname
+    upvar #0 viewfiles current_viewfiles
+    upvar #0 viewargs current_viewargs
+    upvar #0 viewargscmd current_viewargscmd
+    upvar #0 viewperm current_viewperm
+    upvar #0 nextviewnum current_nextviewnum
+    upvar #0 use_ttk current_use_ttk
 
     if {$stuffsaved} return
     if {![winfo viewable .]} return
@@ -2821,16 +2834,24 @@ proc savestuff {w} {
 	if {$::tcl_platform(platform) eq {windows}} {
 	    file attributes $config_file_tmp -hidden true
 	}
+	if {[file exists $config_file]} {
+	    source $config_file
+	}
 	foreach var_name $config_variables {
 	    upvar #0 $var_name var
-	    puts $f [list set $var_name $var]
+	    upvar 0 $var_name old_var
+	    if {!$config_variable_changed($var_name) && [info exists old_var]} {
+		puts $f [list set $var_name $old_var]
+	    } else {
+		puts $f [list set $var_name $var]
+	    }
 	}
 
 	puts $f "set geometry(main) [wm geometry .]"
 	puts $f "set geometry(state) [wm state .]"
 	puts $f "set geometry(topwidth) [winfo width .tf]"
 	puts $f "set geometry(topheight) [winfo height .tf]"
-	if {$use_ttk} {
+	if {$current_use_ttk} {
 	    puts $f "set geometry(pwsash0) \"[.tf.histframe.pwclist sashpos 0] 1\""
 	    puts $f "set geometry(pwsash1) \"[.tf.histframe.pwclist sashpos 1] 1\""
 	} else {
@@ -2841,9 +2862,9 @@ proc savestuff {w} {
 	puts $f "set geometry(botheight) [winfo height .bleft]"
 
 	puts -nonewline $f "set permviews {"
-	for {set v 0} {$v < $nextviewnum} {incr v} {
-	    if {$viewperm($v)} {
-		puts $f "{[list $viewname($v) $viewfiles($v) $viewargs($v) $viewargscmd($v)]}"
+	for {set v 0} {$v < $current_nextviewnum} {incr v} {
+	    if {$current_viewperm($v)} {
+		puts $f "{[list $current_viewname($v) $current_viewfiles($v) $current_viewargs($v) $current_viewargscmd($v)]}"
 	    }
 	}
 	puts $f "}"
@@ -12600,6 +12621,10 @@ set config_variables {
     linehoveroutlinecolor mainheadcirclecolor workingfilescirclecolor
     indexcirclecolor circlecolors linkfgcolor circleoutlinecolor
 }
+foreach var $config_variables {
+    set config_variable_changed($var) 0
+    trace add variable $var write config_variable_change_cb
+}
 
 parsefont mainfont $mainfont
 eval font create mainfont [fontflags mainfont]
-- 
2.0.1.1697.g73c6810