naughty.dbus: Fix inline icon data handling

LGI truncates GVariant bytestring instances at the first embedded \0
byte when using .value for "unwrapping". This commit works around that
problem by avoiding the .value API for accessing the image data [0].

Thanks a lot to Will Dietz for finding this problem and for providing a
preliminary patch fixing the problem. That saved me a lot of time [1].

[0]: https://github.com/pavouk/lgi/pull/223
[1]: eecdeb7d46

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/naughty/dbus.lua

@@ -191,7 +191,17 @@ local function protected_method_call(_, sender, object_path, interface, method,
             if icon ~= "" then
                 args.icon = icon
             elseif hints.icon_data or hints.image_data then
-                if hints.icon_data == nil then hints.icon_data = hints.image_data end
+                -- Icon data is a bit complex and hence needs special care:
+                -- .value breaks with the array of bytes (ay) that we get here.
+                -- So, bypass it and look up the needed value differently
+                local icon_data
+                for k, v in parameters:get_child_value(7 - 1):pairs() do
+                    if k == "icon_data" then
+                        icon_data = v
+                    elseif k == "image_data" and icon_data == nil then
+                        icon_data = v
+                    end
+                end
 
                 -- icon_data is an array:
                 -- 1 -> width
@@ -201,8 +211,12 @@ local function protected_method_call(_, sender, object_path, interface, method,
                 -- 5 -> bits per sample
                 -- 6 -> channels
                 -- 7 -> data
-                local w, h, rowstride, _, _, channels, icon_data = unpack(hints.icon_data)
+
-                args.icon = convert_icon(w, h, rowstride, channels, icon_data)
+                -- Get the value as a GVariant and then use LGI's special
+                -- GVariant.data to get that as an LGI byte buffer. That one can
+                -- then by converted to a string via its __tostring metamethod.
+                local data = tostring(icon_data:get_child_value(7 - 1).data)
+                args.icon = convert_icon(icon_data[1], icon_data[2], icon_data[3], icon_data[6], data)
             end
             if replaces_id and replaces_id ~= "" and replaces_id ~= 0 then
                 args.replaces_id = replaces_id