gitk: Remember the view in the history list

When moving backwards or forwards through the history list, this
automatically switches the view so that each point that we jump to
is shown in the same view that it was originally displayed in.

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

gitk

@@ -959,7 +959,8 @@ proc showview {n} {
 		     $commitidx $rowlaidout $rowoptim $numcommits \
 		     $linesegends $leftover $commfd]
 	    fileevent $commfd readable {}
-	} elseif {![info exists viewdata($curview)]} {
+	} elseif {![info exists viewdata($curview)]
+		  || [lindex $viewdata($curview) 0] ne {}} {
 	    set viewdata($curview) \
 		[list {} $displayorder $parentlist $childlist $rowidlist \
 		     $rowoffsets $rowrangelist $commitlisted]
@@ -1035,6 +1036,14 @@ proc showview {n} {
     allcanvs yview moveto $yf
     drawvisible
     selectline $row 0
+    if {$phase eq {}} {
+	global maincursor textcursor
+	. config -cursor $maincursor
+	settextcursor $textcursor
+    } else {
+	. config -cursor watch
+	settextcursor watch
+    }
 }
 
 proc shortids {ids} {
@@ -2301,7 +2310,7 @@ proc stopfindproc {{done 0}} {
     }
     if {[info exists findinprogress]} {
 	unset findinprogress
-	if {$phase != "incrdraw"} {
+	if {$phase eq {}} {
 	    . config -cursor $maincursor
 	    settextcursor $textcursor
 	}
@@ -2840,17 +2849,18 @@ proc unselectline {} {
 }
 
 proc addtohistory {cmd} {
-    global history historyindex
+    global history historyindex curview
 
+    set elt [list $curview $cmd]
     if {$historyindex > 0
-	&& [lindex $history [expr {$historyindex - 1}]] == $cmd} {
+	&& [lindex $history [expr {$historyindex - 1}]] == $elt} {
 	return
     }
 
     if {$historyindex < [llength $history]} {
-	set history [lreplace $history $historyindex end $cmd]
+	set history [lreplace $history $historyindex end $elt]
     } else {
-	lappend history $cmd
+	lappend history $elt
     }
     incr historyindex
     if {$historyindex > 1} {
@@ -2861,13 +2871,23 @@ proc addtohistory {cmd} {
     .ctop.top.bar.rightbut conf -state disabled
 }
 
+proc godo {elt} {
+    global curview
+
+    set view [lindex $elt 0]
+    set cmd [lindex $elt 1]
+    if {$curview != $view} {
+	showview $view
+    }
+    eval $cmd
+}
+
 proc goback {} {
     global history historyindex
 
     if {$historyindex > 1} {
 	incr historyindex -1
-	set cmd [lindex $history [expr {$historyindex - 1}]]
+	godo [lindex $history [expr {$historyindex - 1}]]
-	eval $cmd
 	.ctop.top.bar.rightbut conf -state normal
     }
     if {$historyindex <= 1} {
@@ -2881,7 +2901,7 @@ proc goforw {} {
     if {$historyindex < [llength $history]} {
 	set cmd [lindex $history $historyindex]
 	incr historyindex
-	eval $cmd
+	godo $cmd
 	.ctop.top.bar.leftbut conf -state normal
     }
     if {$historyindex >= [llength $history]} {