Bug 564016 - Include c:prefix in typelib, use it to optimize find_by_gtype

Parse the c:prefix from the .gir, include it in the header.  Armed with this
information, we can now optimize lookups of GTypes because we
have the requirement that GTypes must start with the c:prefix.  We do
fall back though if a lookup fails.

1 files changed, 72 insertions, 4 deletions

diff --git a/girepository/girepository.c b/girepository/girepository.c
index 06ea13c5..a2a8504d 100644
--- a/girepository/girepository.c
+++ b/girepository/girepository.c
@@ -517,6 +517,7 @@ typedef struct
   GIRepository *repo;
   gint index;
   const gchar *name;
+  gboolean type_firstpass;
   const gchar *type;
   GIBaseInfo *iface;
 } IfaceData;
@@ -528,6 +529,7 @@ find_interface (gpointer key,
 {
   gint i;
   GTypelib *typelib = (GTypelib *)value;
+  Header *header = (Header *) typelib->data;
   IfaceData *iface_data = (IfaceData *)data;
   gint index;
   gint n_entries;
@@ -553,6 +555,28 @@ find_interface (gpointer key,
     }
   else if (iface_data->type)
     {
+      const char *c_prefix;
+      /* Inside each typelib, we include the "C prefix" which acts as
+       * a namespace mechanism.  For GtkTreeView, the C prefix is Gtk.
+       * Given the assumption that GTypes for a library also use the
+       * C prefix, we know we can skip examining a typelib if our
+       * target type does not have this typelib's C prefix.
+       *
+       * However, not every class library necessarily conforms to this,
+       * e.g. Clutter has Cogl inside it.  So, we split this into two
+       * passes.  First we try a lookup, skipping things which don't
+       * have the prefix.  If that fails then we try a global lookup,
+       * ignoring the prefix.
+       *
+       * See http://bugzilla.gnome.org/show_bug.cgi?id=564016
+       */
+      c_prefix = g_typelib_get_string (typelib, header->c_prefix);
+      if (iface_data->type_firstpass && c_prefix != NULL)
+        {
+          if (g_ascii_strncasecmp (c_prefix, iface_data->type, strlen (c_prefix)) != 0)
+            return;
+        }
+
       for (i = 1; i <= n_entries; i++)
 	{
 	  RegisteredTypeBlob *blob;
@@ -638,8 +662,8 @@ g_irepository_get_info (GIRepository *repository,
  * in order to locate the metadata, the namespace corresponding to
  * the type must first have been loaded.  There is currently no
  * mechanism for determining the namespace which corresponds to an
- * arbitrary GType - thus, this function will function most reliably
- * when you have expect the GType to be from a known namespace.
+ * arbitrary GType - thus, this function will operate most reliably
+ * when you know the GType to originate from be from a loaded namespace.
  *
  * Returns: #GIBaseInfo representing metadata about @type, or %NULL
  */
@@ -659,6 +683,7 @@ g_irepository_find_by_gtype (GIRepository *repository,
 
   data.repo = repository;
   data.name = NULL;
+  data.type_firstpass = TRUE;
   data.type = g_type_name (gtype);
   data.index = -1;
   data.iface = NULL;
@@ -666,12 +691,19 @@ g_irepository_find_by_gtype (GIRepository *repository,
   g_hash_table_foreach (repository->priv->typelibs, find_interface, &data);
   g_hash_table_foreach (repository->priv->lazy_typelibs, find_interface, &data);
 
+  /* We do two passes; see comment in find_interface */
+  if (!data.iface)
+    {
+      data.type_firstpass = FALSE;
+      g_hash_table_foreach (repository->priv->typelibs, find_interface, &data);
+      g_hash_table_foreach (repository->priv->lazy_typelibs, find_interface, &data);
+    }
+
   if (data.iface)
     g_hash_table_insert (repository->priv->info_by_gtype,
                          (gpointer) gtype,
                          g_base_info_ref (data.iface));
 
-
   return data.iface;
 }
 
@@ -824,7 +856,43 @@ g_irepository_get_shared_library (GIRepository *repository,
 }
 
 /**
- * g_irepository_get_typelib_path:
+ * g_irepository_get_c_prefix
+ * @repository: A #GIRepository, may be %NULL for the default
+ * @namespace: Namespace to inspect
+ *
+ * This function returns the "C prefix", or the C level namespace
+ * associated with the given introspection namespace.  Each C symbol
+ * starts with this prefix, as well each #GType in the library.
+ *
+ * Note: The namespace must have already been loaded using a function
+ * such as #g_irepository_require before calling this function.
+ *
+ * Returns: C namespace prefix, or %NULL if none associated
+ */
+const gchar *
+g_irepository_get_c_prefix (GIRepository *repository,
+                            const gchar  *namespace_)
+{
+  GTypelib *typelib;
+  Header *header;
+
+  g_return_val_if_fail (namespace_ != NULL, NULL);
+
+  repository = get_repository (repository);
+
+  typelib = get_registered (repository, namespace_, NULL);
+
+  g_return_val_if_fail (typelib != NULL, NULL);
+
+  header = (Header *) typelib->data;
+  if (header->shared_library)
+    return g_typelib_get_string (typelib, header->c_prefix);
+  else
+    return NULL;
+}
+
+/**
+ * g_irepository_get_typelib_path
  * @repository: Repository, may be %NULL for the default
  * @namespace_: GI namespace to use, e.g. "Gtk"
  *