git-gui: Extract blame viewer status bar into mega-widget

Our blame viewer has had a very fancy progress bar at the bottom of
the window that shows the current status of the blame engine, which
includes the number of lines completed as both a text and a graphical
meter.  I want to reuse this meter system in other places, such as
during a branch switch where read-tree -v can give us a progress
meter for any long-running operation.

This change extracts the code and refactors it as a widget that we
can take advantage of in locations other than in the blame viewer.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

lib/blame.tcl

@@ -21,7 +21,7 @@ field w_amov     ; # text column: annotations + move tracking
 field w_asim     ; # text column: annotations (simple computation)
 field w_file     ; # text column: actual file data
 field w_cviewer  ; # pane showing commit message
-field status     ; # text variable bound to status bar
+field status     ; # status mega-widget instance
 field old_height ; # last known height of $w.file_pane
 
 # Tk UI colors
@@ -242,14 +242,7 @@ constructor new {i_commit i_path} {
 	pack $w.file_pane.cm.sbx -side bottom -fill x
 	pack $w_cviewer -expand 1 -fill both
 
-	frame $w.status \
-		-borderwidth 1 \
-		-relief sunken
-	label $w.status.l \
-		-textvariable @status \
-		-anchor w \
-		-justify left
-	pack $w.status.l -side left
+	set status [::status_bar::new $w.status]
 
 	menu $w.ctxm -tearoff 0
 	$w.ctxm add command \
@@ -360,19 +353,6 @@ method _load {jump} {
 		set total_lines 0
 	}
 
-	if {[winfo exists $w.status.c]} {
-		$w.status.c coords bar 0 0 0 20
-	} else {
-		canvas $w.status.c \
-			-width 100 \
-			-height [expr {int([winfo reqheight $w.status.l] * 0.6)}] \
-			-borderwidth 1 \
-			-relief groove \
-			-highlightt 0
-		$w.status.c create rectangle 0 0 0 20 -tags bar -fill navy
-		pack $w.status.c -side right
-	}
-
 	if {$history eq {}} {
 		$w_back conf -state disabled
 	} else {
@@ -386,7 +366,7 @@ method _load {jump} {
 	set amov_data [list [list]]
 	set asim_data [list [list]]
 
-	set status "Loading $commit:[escape_path $path]..."
+	$status show "Reading $commit:[escape_path $path]..."
 	$w_path conf -text [escape_path $path]
 	if {$commit eq {}} {
 		set fd [open $path r]
@@ -510,13 +490,16 @@ method _exec_blame {cur_w cur_d options cur_s} {
 	lappend cmd -- $path
 	set fd [open "| $cmd" r]
 	fconfigure $fd -blocking 0 -translation lf -encoding binary
-	fileevent $fd readable [cb _read_blame $fd $cur_w $cur_d $cur_s]
+	fileevent $fd readable [cb _read_blame $fd $cur_w $cur_d]
 	set current_fd $fd
 	set blame_lines 0
-	_status $this $cur_s
+
+	$status start \
+		"Loading$cur_s annotations..." \
+		{lines annotated}
 }
 
-method _read_blame {fd cur_w cur_d cur_s} {
+method _read_blame {fd cur_w cur_d} {
 	upvar #0 $cur_d line_data
 	variable group_colors
 	variable original_options
@@ -697,26 +680,13 @@ method _read_blame {fd cur_w cur_d cur_s} {
 				{ original location}
 		} else {
 			set current_fd {}
-			set status {Annotation complete.}
-			destroy $w.status.c
+			$status stop {Annotation complete.}
 		}
 	} else {
-		_status $this $cur_s
+		$status update $blame_lines $total_lines
 	}
 } ifdeleted { catch {close $fd} }
 
-method _status {cur_s} {
-	set have  $blame_lines
-	set total $total_lines
-	set pdone 0
-	if {$total} {set pdone [expr {100 * $have / $total}]}
-
-	set status [format \
-		"Loading%s annotations... %i of %i lines annotated (%2i%%)" \
-		$cur_s $have $total $pdone]
-	$w.status.c coords bar 0 0 $pdone 20
-}
-
 method _click {cur_w pos} {
 	set lno [lindex [split [$cur_w index $pos] .] 0]
 	_showcommit $this $cur_w $lno

lib/status_bar.tcl

@@ -0,0 +1,76 @@
+# git-gui status bar mega-widget
+# Copyright (C) 2007 Shawn Pearce
+
+class status_bar {
+
+field w         ; # our own window path
+field w_l       ; # text widget we draw messages into
+field w_c       ; # canvas we draw a progress bar into
+field status  {}; # single line of text we show
+field prefix  {}; # text we format into status
+field units   {}; # unit of progress
+
+constructor new {path} {
+	set w $path
+	set w_l $w.l
+	set w_c $w.c
+
+	frame $w \
+		-borderwidth 1 \
+		-relief sunken
+	label $w_l \
+		-textvariable @status \
+		-anchor w \
+		-justify left
+	pack $w_l -side left
+
+	bind $w <Destroy> [cb _delete %W]
+	return $this
+}
+
+method start {msg uds} {
+	if {[winfo exists $w_c]} {
+		$w_c coords bar 0 0 0 20
+	} else {
+		canvas $w_c \
+			-width 100 \
+			-height [expr {int([winfo reqheight $w_l] * 0.6)}] \
+			-borderwidth 1 \
+			-relief groove \
+			-highlightt 0
+		$w_c create rectangle 0 0 0 20 -tags bar -fill navy
+		pack $w_c -side right
+	}
+
+	set status $msg
+	set prefix $msg
+	set units  $uds
+}
+
+method update {have total} {
+	set pdone 0
+	if {$total > 0} {
+		set pdone [expr {100 * $have / $total}]
+	}
+
+	set status [format "%s ... %i of %i %s (%2i%%)" \
+		$prefix $have $total $units $pdone]
+	$w_c coords bar 0 0 $pdone 20
+}
+
+method stop {msg} {
+	destroy $w_c
+	set status $msg
+}
+
+method show {msg} {
+	set status $msg
+}
+
+method _delete {current} {
+	if {$current eq $w} {
+		delete_this
+	}
+}
+
+}