git-gui: Display the size of the pack directory.

Just as we show the amount of disk space taken by the loose objects,
its interesting to know how much space is taken by the packs directory.
So show that in our Database Statistics dialog.

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

git-gui.sh

@@ -2814,6 +2814,16 @@ proc do_stats {} {
 	}
 	close $fd
 
+	set packed_sz 0
+	foreach p [glob -directory [gitdir objects pack] \
+		-type f \
+		-nocomplain -- *] {
+		incr packed_sz [file size $p]
+	}
+	if {$packed_sz > 0} {
+		set stats(size-pack) [expr {$packed_sz / 1024}]
+	}
+
 	set w .stats_view
 	toplevel $w
 	wm geometry $w "+[winfo rootx .]+[winfo rooty .]"
@@ -2839,6 +2849,7 @@ proc do_stats {} {
 		{size            {Disk space used by loose objects} { KiB}}
 		{in-pack         {Number of packed objects}}
 		{packs           {Number of packs}}
+		{size-pack       {Disk space used by packed objects} { KiB}}
 		{prune-packable  {Packed objects waiting for pruning}}
 		{garbage         {Garbage files}}
 		} {