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.

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"
  *

girepository.h

@@ -108,6 +108,8 @@ const gchar * g_irepository_get_typelib_path   (GIRepository *repository,
 						const gchar  *namespace_);
 const gchar * g_irepository_get_shared_library (GIRepository *repository,
 						const gchar  *namespace_);
+const gchar * g_irepository_get_c_prefix (GIRepository *repository,
+                                          const gchar  *namespace_);
 const gchar * g_irepository_get_version (GIRepository *repository,
 					 const gchar  *namespace_);
 

girmodule.c

@@ -31,7 +31,8 @@
 GIrModule *
 g_ir_module_new (const gchar *name, 
 		 const gchar *version,
-		 const gchar *shared_library)
+		 const gchar *shared_library,
+		 const gchar *c_prefix)
 {
   GIrModule *module;
   
@@ -43,6 +44,7 @@ g_ir_module_new (const gchar *name,
       module->shared_library = g_strdup (shared_library);
   else
       module->shared_library = NULL;
+  module->c_prefix = g_strdup (c_prefix);
   module->dependencies = NULL;
   module->entries = NULL;
 
@@ -229,11 +231,13 @@ g_ir_module_build_typelib (GIrModule  *module,
     }
 
   /* Adjust size for strings allocated in header below specially */
-  size += strlen (module->name);
+  size += ALIGN_VALUE (strlen (module->name) + 1, 4);
   if (module->shared_library) 
-    size += strlen (module->shared_library);
+    size += ALIGN_VALUE (strlen (module->shared_library) + 1, 4);
   if (dependencies != NULL)
-    size += strlen (dependencies);
+    size += ALIGN_VALUE (strlen (dependencies) + 1, 4);
+  if (module->c_prefix != NULL)
+    size += ALIGN_VALUE (strlen (module->c_prefix) + 1, 4);
 
   g_message ("allocating %d bytes (%d header, %d directory, %d entries)\n", 
 	  size, header_size, dir_size, size - header_size - dir_size);
@@ -250,6 +254,9 @@ g_ir_module_build_typelib (GIrModule  *module,
   header->n_local_entries = n_local_entries;
   header->n_attributes = 0;
   header->attributes = 0; /* filled in later */
+  /* NOTE: When writing strings to the typelib here, you should also update
+   * the size calculations above.
+   */
   if (dependencies != NULL)
     header->dependencies = write_string (dependencies, strings, data, &header_size);
   else
@@ -260,6 +267,10 @@ g_ir_module_build_typelib (GIrModule  *module,
   header->shared_library = (module->shared_library?
                              write_string (module->shared_library, strings, data, &header_size)
                              : 0);
+  if (module->c_prefix != NULL)
+    header->c_prefix = write_string (module->c_prefix, strings, data, &header_size);
+  else
+    header->c_prefix = 0;
   header->directory = ALIGN_VALUE (header_size, 4);
   header->entry_blob_size = sizeof (DirEntry);
   header->function_blob_size = sizeof (FunctionBlob);

girmodule.h

@@ -34,6 +34,7 @@ struct _GIrModule
   gchar *name;
   gchar *version;
   gchar *shared_library;
+  gchar *c_prefix;
   GList *dependencies;
   GList *entries;
 
@@ -50,7 +51,8 @@ struct _GIrModule
 
 GIrModule *g_ir_module_new            (const gchar *name,
 				       const gchar *nsversion,
-				       const gchar *module_filename);
+				       const gchar *module_filename,
+				       const gchar *c_prefix);
 void       g_ir_module_free           (GIrModule  *module);
 
 void       g_ir_module_add_include_module (GIrModule  *module,

girparser.c

@@ -88,6 +88,7 @@ struct _ParseContext
   GHashTable *disguised_structures;
 
   const char *namespace;
+  const char *c_prefix;
   GIrModule *current_module;
   GSList *node_stack;
   GIrNode *current_typed;
@@ -2547,7 +2548,7 @@ start_element_handler (GMarkupParseContext *context,
     case 'n':
       if (strcmp (element_name, "namespace") == 0 && ctx->state == STATE_REPOSITORY)
 	{
-	  const gchar *name, *version, *shared_library;
+	  const gchar *name, *version, *shared_library, *cprefix;
 
 	  if (ctx->current_module != NULL)
 	    {
@@ -2561,6 +2562,7 @@ start_element_handler (GMarkupParseContext *context,
 	  name = find_attribute ("name", attribute_names, attribute_values);
 	  version = find_attribute ("version", attribute_names, attribute_values);
 	  shared_library = find_attribute ("shared-library", attribute_names, attribute_values);
+	  cprefix = find_attribute ("c:prefix", attribute_names, attribute_values);
 
 	  if (name == NULL)
 	    MISSING_ATTRIBUTE (context, error, element_name, "name");
@@ -2577,7 +2579,7 @@ start_element_handler (GMarkupParseContext *context,
 			     "<namespace/> name element '%s' doesn't match file name '%s'",
 			     name, ctx->namespace);
 
-	      ctx->current_module = g_ir_module_new (name, version, shared_library);
+	      ctx->current_module = g_ir_module_new (name, version, shared_library, cprefix);
 
 	      ctx->current_module->aliases = ctx->aliases;
 	      ctx->aliases = NULL;

gtypelib.c

@@ -161,7 +161,7 @@ g_typelib_check_sanity (void)
    * Everything else in the code however should be using sizeof().
    */
   
-  CHECK_SIZE (Header, 108);
+  CHECK_SIZE (Header, 112);
   CHECK_SIZE (DirEntry, 12);
   CHECK_SIZE (SimpleTypeBlob, 4);
   CHECK_SIZE (ArgBlob, 16);

gtypelib.h

@@ -247,6 +247,7 @@ typedef struct {
   guint32 namespace;
   guint32 nsversion;
   guint32 shared_library;
+  guint32 c_prefix;
 
   guint16 entry_blob_size;
   guint16 function_blob_size;