git-gui: Allow users to browse any branch, not just the current one

We now allow users to pick which commit they want to browse through
our revision picking mega-widget.  This opens up in a dialog first,
and then opens a tree browser for that selected commit.  It is a very
simple approach and requires minimal code changes.

I also clarified the language a bit in the Repository menu, to show
that these actions will access files.  Just in case a user is not
quite sure what specific action they are looking for, but they know
they want some sort of file thing.

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

git-gui.sh

@@ -1670,9 +1670,12 @@ if {[is_enabled transport]} {
 menu .mbar.repository
 
 .mbar.repository add command \
-	-label {Browse Current Branch} \
+	-label {Browse Current Branch's Files} \
 	-command {browser::new $current_branch}
-trace add variable current_branch write ".mbar.repository entryconf [.mbar.repository index last] -label \"Browse \$current_branch\" ;#"
+trace add variable current_branch write ".mbar.repository entryconf [.mbar.repository index last] -label \"Browse \$current_branch's Files\" ;#"
+.mbar.repository add command \
+	-label {Browse Branch Files...} \
+	-command browser_open::dialog
 .mbar.repository add separator
 
 .mbar.repository add command \

lib/browser.tcl

@@ -243,3 +243,56 @@ method _read {fd} {
 }
 
 }
+
+class browser_open {
+
+field w              ; # widget path
+field w_rev          ; # mega-widget to pick the initial revision
+
+constructor dialog {} {
+	make_toplevel top w
+	wm title $top "[appname] ([reponame]): Browse Branch Files"
+	if {$top ne {.}} {
+		wm geometry $top "+[winfo rootx .]+[winfo rooty .]"
+	}
+
+	label $w.header \
+		-text {Browse Branch Files} \
+		-font font_uibold
+	pack $w.header -side top -fill x
+
+	frame $w.buttons
+	button $w.buttons.browse -text Browse \
+		-default active \
+		-command [cb _open]
+	pack $w.buttons.browse -side right
+	button $w.buttons.cancel -text {Cancel} \
+		-command [list destroy $w]
+	pack $w.buttons.cancel -side right -padx 5
+	pack $w.buttons -side bottom -fill x -pady 10 -padx 10
+
+	set w_rev [::choose_rev::new $w.rev {Revision}]
+	$w_rev bind_listbox <Double-Button-1> [cb _open]
+	pack $w.rev -anchor nw -fill both -expand 1 -pady 5 -padx 5
+
+	bind $w <Visibility> [cb _visible]
+	bind $w <Key-Escape> [list destroy $w]
+	bind $w <Key-Return> [cb _open]\;break
+	tkwait window $w
+}
+
+method _open {} {
+	if {[catch {$w_rev commit_or_die} err]} {
+		return
+	}
+	set name [$w_rev get]
+	destroy $w
+	browser::new $name
+}
+
+method _visible {} {
+	grab $w
+	$w_rev focus_filter
+}
+
+}