[mutter] monitor: improve heuristic to determine display output name

[Cosimo Cecchi <cosimoc src gnome org>]

commit 477acddf642d735ef036a95fda6f4d7f6b522fd1
Author: Cosimo Cecchi <cosimo endlessm com>
Date:   Mon Jan 6 18:26:03 2014 -0800

    monitor: improve heuristic to determine display output name
    
    Under some circumstances, for example when the display controller driver
    doesn't report back the correct EDID, or under VirtualBox, Mutter
    returns suboptimal strings for an output display name, leading to funny
    labels like 'Unknown 0"', or '(null) 0"' in the Settings panel.
    
    This commit improves our heuristic in three ways:
    - we now avoid putting inches in the display name if either dimension is
      zero
    - we use the vendor name in case we're not able to lookup its PnP id
      from the database. Previously we would have passed over '(null)'
    - as a special edge-case, when neither inches nor vendor are known, we
      use the string 'Unknown Display'
    
    Finally, we make the combined vendor + inches string translatable, as
    different languages might want to move the size part of the string to a
    position different than the end.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=721674

 src/core/monitor.c |   65 ++++++++++++++++++++++++++++++++--------------------
 1 files changed, 40 insertions(+), 25 deletions(-)
---
diff --git a/src/core/monitor.c b/src/core/monitor.c
index 6d65f9e..ba8c617 100644
--- a/src/core/monitor.c
+++ b/src/core/monitor.c
@@ -691,46 +691,61 @@ static char *
 make_display_name (MetaMonitorManager *manager,
                    MetaOutput         *output)
 {
+  char *inches = NULL;
+  char *vendor_name = NULL;
+  char *ret;
+  gboolean is_unknown = FALSE;
+
   if (g_str_has_prefix (output->name, "LVDS") ||
       g_str_has_prefix (output->name, "eDP"))
-    return g_strdup (_("Built-in display"));
+    {
+      ret = g_strdup (_("Built-in display"));
+      goto out;
+    }
 
-  if (output->width_mm != -1 && output->height_mm != -1)
+  if (output->width_mm > 0 && output->height_mm > 0)
     {
       double d = sqrt (output->width_mm * output->width_mm +
                        output->height_mm * output->height_mm);
-      char *inches = diagonal_to_str (d / 25.4);
-      char *vendor_name;
-      char *ret;
-
-      if (g_strcmp0 (output->vendor, "unknown") != 0)
-        {
-          if (!manager->pnp_ids)
-            manager->pnp_ids = gnome_pnp_ids_new ();
+      inches = diagonal_to_str (d / 25.4);
+    }
 
-          vendor_name = gnome_pnp_ids_get_pnp_id (manager->pnp_ids,
-                                                  output->vendor);
+  if (g_strcmp0 (output->vendor, "unknown") != 0)
+    {
+      if (!manager->pnp_ids)
+        manager->pnp_ids = gnome_pnp_ids_new ();
 
-          ret = g_strdup_printf ("%s %s", vendor_name, inches);
+      vendor_name = gnome_pnp_ids_get_pnp_id (manager->pnp_ids,
+                                              output->vendor);
 
-          g_free (vendor_name);
-        }
+      if (!vendor_name)
+        vendor_name = g_strdup (output->vendor);
+    }
+  else
+    {
+      if (inches != NULL)
+        vendor_name = g_strdup (_("Unknown"));
       else
-        {
-          /* TRANSLATORS: this is a monitor name (in case we don't know
-             the vendor), it's Unknown followed by a size in inches,
-             like 'Unknown 15"'
-          */
-          ret = g_strdup_printf (_("Unknown %s"), inches);
-        }
+        vendor_name = g_strdup (_("Unknown Display"));
+    }
 
-      g_free (inches);
-      return ret;
+  if (inches != NULL)
+    {
+      /* TRANSLATORS: this is a monitor vendor name, followed by a
+       * size in inches, like 'Dell 15"'
+       */
+      ret = g_strdup_printf (_("%s %s"), vendor_name, inches);
     }
   else
     {
-      return g_strdup (output->vendor);
+      ret = g_strdup (vendor_name);
     }
+
+ out:
+  g_free (inches);
+  g_free (vendor_name);
+
+  return ret;
 }
 
 static gboolean