wibox.drawable: add __tostring meta method

lib/awful/titlebar.lua

@@ -75,7 +75,7 @@ local function new(c, args)
 
     local ret
     if not bars[position] then
-        ret = drawable(d, nil)
+        ret = drawable(d, nil, "awful.titlebar")
         local function update_colors()
             local args = bars[position].args
             ret:set_bg(get_color("bg", c, args))

lib/wibox/drawable.lua

@@ -229,7 +229,7 @@ local function setup_signals(_drawable)
     clone_signal("property::y")
 end
 
-function drawable.new(d, widget_arg)
+function drawable.new(d, widget_arg, drawable_name)
     local ret = object()
     ret.drawable = d
     ret.widget_arg = widget_arg or ret
@@ -287,6 +287,15 @@ function drawable.new(d, widget_arg)
     d:connect_signal("mouse::move", function(_, x, y) handle_motion(ret, x, y) end)
     d:connect_signal("mouse::leave", function() handle_leave(ret) end)
 
+    -- Add __tostring method to metatable.
+    ret.drawable_name = drawable_name or object.modulename(3)
+    local mt = {}
+    local orig_string = tostring(ret)
+    mt.__tostring = function(o)
+        return string.format("%s (%s)", ret.drawable_name, orig_string)
+    end
+    ret = setmetatable(ret, mt)
+
     -- Make sure the drawable is drawn at least once
     ret.draw()
 

lib/wibox/init.lua

@@ -108,7 +108,8 @@ local function new(args)
     local ret = object()
     local w = capi.drawin(args)
     ret.drawin = w
-    ret._drawable = wibox.drawable(w.drawable, ret)
+    ret._drawable = wibox.drawable(w.drawable, ret,
+        "wibox drawable (" .. object.modulename(3) .. ")")
 
     for k, v in pairs(wibox) do
         if type(v) == "function" then