Merge branch 'th/main-sources-dict-as-set' into 'main'

gmain: optimize "context->sources" hash table to use as set

See merge request GNOME/glib!3664

glib/ghash.c

@@ -2552,6 +2552,50 @@ g_int_hash (gconstpointer v)
   return *(const gint*) v;
 }
 
+/**
+ * g_uint_equal:
+ * @v1: (not nullable): a pointer to a #guint key
+ * @v2: (not nullable): a pointer to a #guint key to compare with @v1
+ *
+ * Compares the two #guint values being pointed to and returns
+ * %TRUE if they are equal.
+ * It can be passed to g_hash_table_new() as the @key_equal_func
+ * parameter, when using non-%NULL pointers to integers as keys in a
+ * #GHashTable.
+ *
+ * Note that this function acts on pointers to #guint, not on #guint
+ * directly: if your hash table's keys are of the form
+ * `GUINT_TO_POINTER (n)`, use g_direct_equal() instead.
+ *
+ * Returns: %TRUE if the two keys match.
+ */
+gboolean
+g_uint_equal (gconstpointer v1,
+              gconstpointer v2)
+{
+  return *((const guint *) v1) == *((const guint *) v2);
+}
+
+/**
+ * g_uint_hash:
+ * @v: (not nullable): a pointer to a #guint key
+ *
+ * Converts a pointer to a #guint to a hash value.
+ * It can be passed to g_hash_table_new() as the @hash_func parameter,
+ * when using non-%NULL pointers to integer values as keys in a #GHashTable.
+ *
+ * Note that this function acts on pointers to #guint, not on #guint
+ * directly: if your hash table's keys are of the form
+ * `GUINT_TO_POINTER (n)`, use g_direct_hash() instead.
+ *
+ * Returns: a hash value corresponding to the key.
+ */
+guint
+g_uint_hash (gconstpointer v)
+{
+  return *(const guint *) v;
+}
+
 /**
  * g_int64_equal:
  * @v1: (not nullable): a pointer to a #gint64 key

glib/glib-private.h

@@ -63,6 +63,18 @@ void __lsan_ignore_object (const void *p) __attribute__ ((weak));
 
 #endif
 
+/**
+ * G_CONTAINER_OF:
+ * @ptr: a pointer to a member @field of type @type.
+ * @type: the type of the container in which @field is embedded.
+ * @field: the name of the field in @type.
+ *
+ * Casts away constness of @ptr.
+ *
+ * Returns: a pointer to the container, so that "&(@container)->field == (@ptr)" holds.
+ */
+#define G_CONTAINER_OF(ptr, type, field) ((type *) G_STRUCT_MEMBER_P (ptr, -G_STRUCT_OFFSET (type, field)))
+
 /*
  * g_leak_sanitizer_is_supported:
  *
@@ -303,4 +315,7 @@ GLibPrivateVTable *glib__private__ (void);
 # define GLIB_DEFAULT_LOCALE ""
 #endif
 
+gboolean g_uint_equal (gconstpointer v1, gconstpointer v2);
+guint g_uint_hash (gconstpointer v);
+
 #endif /* __GLIB_PRIVATE_H__ */

glib/gmain.c

@@ -637,7 +637,7 @@ g_main_context_new_with_flags (GMainContextFlags flags)
   g_mutex_init (&context->mutex);
   g_cond_init (&context->cond);
 
-  context->sources = g_hash_table_new (NULL, NULL);
+  context->sources = g_hash_table_new (g_uint_hash, g_uint_equal);
   context->owner = NULL;
   context->flags = flags;
   context->waiters = NULL;
@@ -1166,13 +1166,13 @@ g_source_attach_unlocked (GSource      *source,
    */
   do
     id = context->next_id++;
-  while (id == 0 || g_hash_table_contains (context->sources, GUINT_TO_POINTER (id)));
+  while (id == 0 || g_hash_table_contains (context->sources, &id));
 
   source->context = context;
   source->source_id = id;
   g_source_ref (source);
 
-  g_hash_table_insert (context->sources, GUINT_TO_POINTER (id), source);
+  g_hash_table_add (context->sources, &source->source_id);
 
   source_add_to_context (source, context);
 
@@ -2239,7 +2239,7 @@ g_source_unref_internal (GSource      *source,
 	    g_warning (G_STRLOC ": ref_count == 0, but source was still attached to a context!");
 	  source_remove_from_context (source, context);
 
-          g_hash_table_remove (context->sources, GUINT_TO_POINTER (source->source_id));
+	  g_hash_table_remove (context->sources, &source->source_id);
 	}
 
       if (source->source_funcs->finalize)
@@ -2348,7 +2348,8 @@ GSource *
 g_main_context_find_source_by_id (GMainContext *context,
                                   guint         source_id)
 {
-  GSource *source;
+  GSource *source = NULL;
+  gconstpointer ptr;
 
   g_return_val_if_fail (source_id > 0, NULL);
 
@@ -2356,12 +2357,15 @@ g_main_context_find_source_by_id (GMainContext *context,
     context = g_main_context_default ();
 
   LOCK_CONTEXT (context);
-  source = g_hash_table_lookup (context->sources, GUINT_TO_POINTER (source_id));
+  ptr = g_hash_table_lookup (context->sources, &source_id);
+  if (ptr)
+    {
+      source = G_CONTAINER_OF (ptr, GSource, source_id);
+      if (SOURCE_DESTROYED (source))
+        source = NULL;
+    }
   UNLOCK_CONTEXT (context);
 
-  if (source && SOURCE_DESTROYED (source))
-    source = NULL;
-
   return source;
 }