[glib] Add G_SIGNAL_DEPRECATED

[Marc-Andre Lureau <malureau src gnome org>]

commit fb95c20c965bc241fc9d519afede94d3bc7838a8
Author: Marc-Andrà Lureau <marcandre lureau gmail com>
Date:   Mon Nov 7 20:04:15 2011 +0100

    Add G_SIGNAL_DEPRECATED
    
    Similar to G_PARAM_DEPRECATED. It will warn only for users of the
    signals, so a signal can still be emited without warning, for
    compatibility reasons.
    
    Apparently, there is no way user flags could have been used before,
    so that shouldn't break anyone.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=663581

 gobject/gobject.c |    2 +-
 gobject/gsignal.c |   32 +++++++++++++++++++++++++++++++-
 gobject/gsignal.h |    8 ++++++--
 3 files changed, 38 insertions(+), 4 deletions(-)
---
diff --git a/gobject/gobject.c b/gobject/gobject.c
index faf3cef..6e20aa0 100644
--- a/gobject/gobject.c
+++ b/gobject/gobject.c
@@ -1171,7 +1171,7 @@ object_set_property (GObject             *object,
   if (enable_diagnostic[0] == '1')
     {
       if (pspec->flags & G_PARAM_DEPRECATED)
-        g_warning ("The property %s::%s is deprecated and shouldn't be used "
+        g_warning ("The property %s:%s is deprecated and shouldn't be used "
                    "anymore. It will be removed in a future version.",
                    G_OBJECT_TYPE_NAME (object), pspec->name);
     }
diff --git a/gobject/gsignal.c b/gobject/gsignal.c
index 4ea57c5..5736732 100644
--- a/gobject/gsignal.c
+++ b/gobject/gsignal.c
@@ -180,6 +180,7 @@ static	      gboolean		signal_emit_unlocked_R	(SignalNode	 *node,
 							 GValue		 *return_value,
 							 const GValue	 *instance_and_params);
 static const gchar *            type_debug_name         (GType            type);
+static void                     node_check_deprecated   (const SignalNode *node);
 
 
 /* --- structures --- */
@@ -205,7 +206,7 @@ struct _SignalNode
   
   /* reinitializable portion */
   guint		     test_class_offset : 12;
-  guint              flags : 8;
+  guint              flags : 9;
   guint              n_params : 8;
   GType		    *param_types; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
   GType		     return_type; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
@@ -929,6 +930,9 @@ g_signal_add_emission_hook (guint               signal_id,
       g_hook_list_init (node->emission_hooks, sizeof (SignalHook));
       node->emission_hooks->finalize_hook = signal_finalize_hook;
     }
+
+  node_check_deprecated (node);
+
   hook = g_hook_alloc (node->emission_hooks);
   hook->data = hook_data;
   hook->func = (gpointer) hook_func;
@@ -1804,6 +1808,7 @@ g_signal_override_class_closure (guint     signal_id,
   
   SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
+  node_check_deprecated (node);
   if (!g_type_is_a (instance_type, node->itype))
     g_warning ("%s: type `%s' cannot be overridden for signal id `%u'", G_STRLOC, type_debug_name (instance_type), signal_id);
   else
@@ -2229,6 +2234,29 @@ g_signal_connect_closure (gpointer     instance,
   return handler_seq_no;
 }
 
+static void
+node_check_deprecated (const SignalNode *node)
+{
+  static const gchar * g_enable_diagnostic = NULL;
+
+  if (G_UNLIKELY (!g_enable_diagnostic))
+    {
+      g_enable_diagnostic = g_getenv ("G_ENABLE_DIAGNOSTIC");
+      if (!g_enable_diagnostic)
+        g_enable_diagnostic = "0";
+    }
+
+  if (g_enable_diagnostic[0] == '1')
+    {
+      if (node->flags & G_SIGNAL_DEPRECATED)
+        {
+          g_warning ("The signal %s::%s is deprecated and shouldn't be used "
+                     "anymore. It will be removed in a future version.",
+                     type_debug_name (node->itype), node->name);
+        }
+    }
+}
+
 /**
  * g_signal_connect_data:
  * @instance: the instance to connect to.
@@ -2274,6 +2302,8 @@ g_signal_connect_data (gpointer       instance,
     {
       SignalNode *node = LOOKUP_SIGNAL_NODE (signal_id);
 
+      node_check_deprecated (node);
+
       if (detail && !(node->flags & G_SIGNAL_DETAILED))
 	g_warning ("%s: signal `%s' does not support details", G_STRLOC, detailed_signal);
       else if (!g_type_is_a (itype, node->itype))
diff --git a/gobject/gsignal.h b/gobject/gsignal.h
index 0fae33e..5d8ead8 100644
--- a/gobject/gsignal.h
+++ b/gobject/gsignal.h
@@ -110,6 +110,9 @@ typedef gboolean (*GSignalAccumulator)	(GSignalInvocationHint *ihint,
  * @G_SIGNAL_NO_HOOKS: No emissions hooks are supported for this signal.
  * @G_SIGNAL_MUST_COLLECT: Varargs signal emission will always collect the
  *   arguments, even if there are no signal handlers connected.  Since 2.30.
+ * @G_SIGNAL_DEPRECATED: The signal is deprecated and will be removed
+ *   in a future version. A warning will be generated if it is connected while
+ *   running with G_ENABLE_DIAGNOSTIC=1.  Since 2.32.
  * 
  * The signal flags are used to specify a signal's behaviour, the overall
  * signal description outlines how especially the RUN flags control the
@@ -124,14 +127,15 @@ typedef enum
   G_SIGNAL_DETAILED	= 1 << 4,
   G_SIGNAL_ACTION	= 1 << 5,
   G_SIGNAL_NO_HOOKS	= 1 << 6,
-  G_SIGNAL_MUST_COLLECT = 1 << 7
+  G_SIGNAL_MUST_COLLECT = 1 << 7,
+  G_SIGNAL_DEPRECATED   = 1 << 8,
 } GSignalFlags;
 /**
  * G_SIGNAL_FLAGS_MASK:
  * 
  * A mask for all #GSignalFlags bits.
  */
-#define G_SIGNAL_FLAGS_MASK  0xff
+#define G_SIGNAL_FLAGS_MASK  0x1ff
 /**
  * GConnectFlags:
  * @G_CONNECT_AFTER: whether the handler should be called before or after the