Change cursor to a hand cursor when over a SHA1 ID link.

This is based on suggestions by Jeff Epler and Linus Torvalds, but
extended so that we do the switching between the watch cursor and
the normal cursor correctly as well.

Also fixed a bug pointed out by Junio Hamano - I wasn't incrementing
the link number (duh!).

gitk

@@ -54,7 +54,7 @@ proc getcommits {rargs} {
     $canv create text 3 3 -anchor nw -text "Reading commits..." \
 	-font $mainfont -tags textitems
     . config -cursor watch
-    $ctext config -cursor watch
+    settextcursor watch
 }
 
 proc getcommitlines {commfd}  {
@@ -277,7 +277,7 @@ proc makewindow {} {
     global canv canv2 canv3 linespc charspc ctext cflist textfont
     global findtype findtypemenu findloc findstring fstring geometry
     global entries sha1entry sha1string sha1but
-    global maincursor textcursor
+    global maincursor textcursor curtextcursor
     global rowctxmenu gaudydiff mergemax
 
     menu .bar
@@ -465,6 +465,7 @@ proc makewindow {} {
 
     set maincursor [. cget -cursor]
     set textcursor [$ctext cget -cursor]
+    set curtextcursor $textcursor
 
     set rowctxmenu .rowctxmenu
     menu $rowctxmenu -tearoff 0
@@ -1142,7 +1143,18 @@ proc finishcommits {} {
 	drawrest $level [llength $startcommits]
     }
     . config -cursor $maincursor
-    $ctext config -cursor $textcursor
+    settextcursor $textcursor
+}
+
+# Don't change the text pane cursor if it is currently the hand cursor,
+# showing that we are over a sha1 ID link.
+proc settextcursor {c} {
+    global ctext curtextcursor
+
+    if {[$ctext cget -cursor] == $curtextcursor} {
+	$ctext config -cursor $c
+    }
+    set curtextcursor $c
 }
 
 proc drawgraph {} {
@@ -1377,7 +1389,7 @@ proc stopfindproc {{done 0}} {
 	unset findinprogress
 	if {$phase != "incrdraw"} {
 	    . config -cursor $maincursor
-	    $ctext config -cursor $textcursor
+	    settextcursor $textcursor
 	}
     }
 }
@@ -1420,7 +1432,7 @@ proc findpatches {} {
     fileevent $f readable readfindproc
     set finddidsel 0
     . config -cursor watch
-    $ctext config -cursor watch
+    settextcursor watch
     set findinprogress 1
 }
 
@@ -1525,7 +1537,7 @@ proc findfiles {} {
     set id $lineid($l)
     set p [lindex $parents($id) 0]
     . config -cursor watch
-    $ctext config -cursor watch
+    settextcursor watch
     set findinprogress 1
     findcont [list $id $p]
     update
@@ -1802,10 +1814,14 @@ proc selectline {l isnew} {
 	set linkid [string range $comment $s $e]
 	if {![info exists idline($linkid)]} continue
 	incr e
-	$ctext tag conf link$i -foreground blue -underline 1
+	$ctext tag add link "$commentstart + $s c" "$commentstart + $e c"
 	$ctext tag add link$i "$commentstart + $s c" "$commentstart + $e c"
 	$ctext tag bind link$i <1> [list selectline $idline($linkid) 1]
+	incr i
     }
+    $ctext tag conf link -foreground blue -underline 1
+    $ctext tag bind link <Enter> { %W configure -cursor hand2 }
+    $ctext tag bind link <Leave> { %W configure -cursor $curtextcursor }
 
     $ctext tag delete Comments
     $ctext tag remove found 1.0 end