=== Released 2.2.0 ===
[platform/upstream/glib.git] / gobject / gsignal.c
index 036ab4b..694f059 100644 (file)
  * MT safe
  */
 
+#include <config.h>
+
 #include        "gsignal.h"
 #include        "gbsearcharray.h"
 #include        "gvaluecollector.h"
 #include       "gvaluetypes.h"
 #include       "gboxed.h"
 #include       <string.h> 
+#include       <signal.h>
 
 
 /* pre allocation configurations
  */
 #define        MAX_STACK_VALUES        (16)
-#define BSA_PRE_ALLOC           (20)
 #define HANDLER_PRE_ALLOC       (48)
-#define EMISSION_PRE_ALLOC      (16)
 
 #define REPORT_BUG      "please report occourance circumstances to gtk-devel-list@gnome.org"
 #ifdef G_ENABLE_DEBUG
 #define IF_DEBUG(debug_type, cond)     if ((_g_type_debug_flags & G_TYPE_DEBUG_ ## debug_type) || cond)
-static volatile gpointer *g_trace_instance_signals = NULL;
-static volatile gpointer *g_trap_instance_signals = NULL;
+static volatile gpointer g_trace_instance_signals = NULL;
+static volatile gpointer g_trap_instance_signals = NULL;
 #endif /* G_ENABLE_DEBUG */
 
 
@@ -111,7 +112,7 @@ static            void              handler_insert          (guint            signal_id,
                                                         gpointer         instance,
                                                         Handler         *handler);
 static       Handler*          handler_lookup          (gpointer         instance,
-                                                        guint            handler_id,
+                                                        gulong           handler_id,
                                                         guint           *signal_id_p);
 static inline HandlerMatch*    handler_match_prepend   (HandlerMatch    *list,
                                                         Handler         *handler,
@@ -130,22 +131,26 @@ static inline void                handler_ref             (Handler         *handler);
 static inline void             handler_unref_R         (guint            signal_id,
                                                         gpointer         instance,
                                                         Handler         *handler);
+static gint                    handler_lists_cmp       (gconstpointer    node1,
+                                                        gconstpointer    node2);
 static inline void             emission_push           (Emission       **emission_list_p,
-                                                        guint            signal_id,
-                                                        GQuark           detail,
-                                                        gpointer         instance,
-                                                        EmissionState   *state_p);
+                                                        Emission        *emission);
 static inline void             emission_pop            (Emission       **emission_list_p,
-                                                        EmissionState   *state_p);
+                                                        Emission        *emission);
 static inline Emission*                emission_find           (Emission        *emission_list,
                                                         guint            signal_id,
                                                         GQuark           detail,
                                                         gpointer         instance);
-static       gboolean          signal_emit_R           (SignalNode      *node,
+static gint                    class_closures_cmp      (gconstpointer    node1,
+                                                        gconstpointer    node2);
+static gint                    signal_key_cmp          (gconstpointer    node1,
+                                                        gconstpointer    node2);
+static       gboolean          signal_emit_unlocked_R  (SignalNode      *node,
                                                         GQuark           detail,
                                                         gpointer         instance,
                                                         GValue          *return_value,
                                                         const GValue    *instance_and_params);
+static const gchar *            type_debug_name         (GType            type);
 
 
 /* --- structures --- */
@@ -174,7 +179,7 @@ struct _SignalNode
   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 */
-  GClosure          *class_closure;
+  GBSearchArray     *class_closure_bsa;
   SignalAccumulator *accumulator;
   GSignalCMarshaller c_marshaller;
   GHookList         *emission_hooks;
@@ -189,11 +194,11 @@ struct _SignalKey
 
 struct _Emission
 {
-  Emission      *next;
-  guint          signal_id;
-  GQuark        detail;
-  gpointer       instance;
-  EmissionState *state_p;
+  Emission             *next;
+  gpointer              instance;
+  GSignalInvocationHint ihint;
+  EmissionState         state;
+  GType                        chain_type;
 };
 
 struct _HandlerList
@@ -203,7 +208,7 @@ struct _HandlerList
 };
 struct _Handler
 {
-  guint         id;
+  gulong        sequential_number;
   Handler      *next;
   Handler      *prev;
   GQuark       detail;
@@ -224,16 +229,34 @@ struct _HandlerMatch
   } d;
 };
 
+typedef struct
+{
+  GType     instance_type; /* 0 for default closure */
+  GClosure *closure;
+} ClassClosure;
+
 
 /* --- variables --- */
-static GBSearchArray  g_signal_key_bsa = { NULL, 0, 0, 0, NULL };
+static GBSearchArray *g_signal_key_bsa = NULL;
+static GBSearchConfig g_signal_key_bconfig = G_STATIC_BCONFIG (sizeof (SignalKey),
+                                                              signal_key_cmp,
+                                                              G_BSEARCH_ARRAY_ALIGN_POWER2);
+static GBSearchConfig g_signal_hlbsa_bconfig = G_STATIC_BCONFIG (sizeof (HandlerList),
+                                                                handler_lists_cmp,
+                                                                G_BSEARCH_ARRAY_DEFER_SHRINK);
+static GBSearchConfig g_class_closure_bconfig = G_STATIC_BCONFIG (sizeof (ClassClosure),
+                                                                 class_closures_cmp,
+                                                                 0);
 static GHashTable    *g_handler_list_bsa_ht = NULL;
 static Emission      *g_recursive_emissions = NULL;
 static Emission      *g_restart_emissions = NULL;
-static GTrashStack   *g_bsa_ts = NULL;
+#ifndef DISABLE_MEM_POOLS
 static GTrashStack   *g_handler_ts = NULL;
-static GTrashStack   *g_emission_ts = NULL;
+#endif
+static gulong         g_handler_sequential_number = 1;
 G_LOCK_DEFINE_STATIC (g_signal_mutex);
+#define        SIGNAL_LOCK()           G_LOCK (g_signal_mutex)
+#define        SIGNAL_UNLOCK()         G_UNLOCK (g_signal_mutex)
 
 
 /* --- signal nodes --- */
@@ -267,7 +290,7 @@ signal_id_lookup (GQuark quark,
       SignalKey *signal_key;
       
       key.itype = type;
-      signal_key = g_bsearch_array_lookup (&g_signal_key_bsa, &key);
+      signal_key = g_bsearch_array_lookup (g_signal_key_bsa, &g_signal_key_bconfig, &key);
       
       if (signal_key)
        return signal_key->signal_id;
@@ -283,7 +306,7 @@ signal_id_lookup (GQuark quark,
       SignalKey *signal_key;
 
       key.itype = ifaces[n_ifaces];
-      signal_key = g_bsearch_array_lookup (&g_signal_key_bsa, &key);
+      signal_key = g_bsearch_array_lookup (g_signal_key_bsa, &g_signal_key_bconfig, &key);
 
       if (signal_key)
        {
@@ -297,6 +320,15 @@ signal_id_lookup (GQuark quark,
 }
 
 static gint
+class_closures_cmp (gconstpointer node1,
+                   gconstpointer node2)
+{
+  const ClassClosure *c1 = node1, *c2 = node2;
+  
+  return G_BSEARCH_ARRAY_CMP (c1->instance_type, c2->instance_type);
+}
+
+static gint
 handler_lists_cmp (gconstpointer node1,
                    gconstpointer node2)
 {
@@ -312,22 +344,23 @@ handler_list_ensure (guint    signal_id,
   GBSearchArray *hlbsa = g_hash_table_lookup (g_handler_list_bsa_ht, instance);
   HandlerList key;
   
+  key.signal_id = signal_id;
+  key.handlers = NULL;
   if (!hlbsa)
     {
-      hlbsa = g_generic_node_alloc (&g_bsa_ts,
-                                    sizeof (GBSearchArray),
-                                    BSA_PRE_ALLOC);
-      hlbsa->cmp_func = handler_lists_cmp;
-      hlbsa->sizeof_node = sizeof (HandlerList);
-      hlbsa->flags = G_BSEARCH_DEFER_SHRINK;
-      hlbsa->n_nodes = 0;
-      hlbsa->nodes = NULL;
+      hlbsa = g_bsearch_array_new (&g_signal_hlbsa_bconfig);
+      hlbsa = g_bsearch_array_insert (hlbsa, &g_signal_hlbsa_bconfig, &key, FALSE);
       g_hash_table_insert (g_handler_list_bsa_ht, instance, hlbsa);
     }
-  key.signal_id = signal_id;
-  key.handlers = NULL;
-  
-  return g_bsearch_array_insert (hlbsa, &key, FALSE);
+  else
+    {
+      GBSearchArray *o = hlbsa;
+
+      hlbsa = g_bsearch_array_insert (o, &g_signal_hlbsa_bconfig, &key, FALSE);
+      if (hlbsa != o)
+       g_hash_table_insert (g_handler_list_bsa_ht, instance, hlbsa);
+    }
+  return g_bsearch_array_lookup (hlbsa, &g_signal_hlbsa_bconfig, &key);
 }
 
 static inline HandlerList*
@@ -339,12 +372,12 @@ handler_list_lookup (guint    signal_id,
   
   key.signal_id = signal_id;
   
-  return hlbsa ? g_bsearch_array_lookup (hlbsa, &key) : NULL;
+  return hlbsa ? g_bsearch_array_lookup (hlbsa, &g_signal_hlbsa_bconfig, &key) : NULL;
 }
 
 static Handler*
 handler_lookup (gpointer instance,
-               guint    handler_id,
+               gulong   handler_id,
                guint   *signal_id_p)
 {
   GBSearchArray *hlbsa = g_hash_table_lookup (g_handler_list_bsa_ht, instance);
@@ -355,11 +388,11 @@ handler_lookup (gpointer instance,
       
       for (i = 0; i < hlbsa->n_nodes; i++)
         {
-          HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, i);
+          HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, &g_signal_hlbsa_bconfig, i);
           Handler *handler;
           
           for (handler = hlist->handlers; handler; handler = handler->next)
-            if (handler->id == handler_id)
+            if (handler->sequential_number == handler_id)
               {
                 if (signal_id_p)
                   *signal_id_p = hlist->signal_id;
@@ -431,7 +464,7 @@ handlers_find (gpointer         instance,
       
       mask = ~mask;
       for (handler = hlist ? hlist->handlers : NULL; handler; handler = handler->next)
-        if (handler->id &&
+        if (handler->sequential_number &&
            ((mask & G_SIGNAL_MATCH_DETAIL) || handler->detail == detail) &&
            ((mask & G_SIGNAL_MATCH_CLOSURE) || handler->closure == closure) &&
             ((mask & G_SIGNAL_MATCH_DATA) || handler->closure->data == data) &&
@@ -456,7 +489,7 @@ handlers_find (gpointer         instance,
           
           for (i = 0; i < hlbsa->n_nodes; i++)
             {
-              HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, i);
+              HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, &g_signal_hlbsa_bconfig, i);
              SignalNode *node = NULL;
               Handler *handler;
               
@@ -468,7 +501,7 @@ handlers_find (gpointer         instance,
                }
              
               for (handler = hlist->handlers; handler; handler = handler->next)
-               if (handler->id &&
+               if (handler->sequential_number &&
                    ((mask & G_SIGNAL_MATCH_DETAIL) || handler->detail == detail) &&
                     ((mask & G_SIGNAL_MATCH_CLOSURE) || handler->closure == closure) &&
                     ((mask & G_SIGNAL_MATCH_DATA) || handler->closure->data == data) &&
@@ -491,16 +524,15 @@ handlers_find (gpointer         instance,
 static inline Handler*
 handler_new (gboolean after)
 {
-  static guint handler_id = 1;
   Handler *handler = g_generic_node_alloc (&g_handler_ts,
                                            sizeof (Handler),
                                            HANDLER_PRE_ALLOC);
 #ifndef G_DISABLE_CHECKS
-  if (handler_id == 0)
+  if (g_handler_sequential_number < 1)
     g_error (G_STRLOC ": handler id overflow, %s", REPORT_BUG);
 #endif
   
-  handler->id = handler_id++;
+  handler->sequential_number = g_handler_sequential_number++;
   handler->prev = NULL;
   handler->next = NULL;
   handler->detail = 0;
@@ -545,9 +577,9 @@ handler_unref_R (guint    signal_id,
           
           hlist->handlers = handler->next;
         }
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       g_closure_unref (handler->closure);
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
       g_generic_node_free (&g_handler_ts, handler);
     }
 }
@@ -589,36 +621,29 @@ handler_insert (guint    signal_id,
 }
 
 static inline void
-emission_push (Emission     **emission_list_p,
-              guint          signal_id,
-              GQuark         detail,
-              gpointer       instance,
-              EmissionState *state_p)
-{
-  Emission *emission = g_generic_node_alloc (&g_emission_ts,
-                                             sizeof (Emission),
-                                             EMISSION_PRE_ALLOC);
+emission_push (Emission **emission_list_p,
+              Emission  *emission)
+{
   emission->next = *emission_list_p;
-  emission->signal_id = signal_id;
-  emission->detail = detail;
-  emission->instance = instance;
-  emission->state_p = state_p;
   *emission_list_p = emission;
 }
 
 static inline void
-emission_pop (Emission     **emission_list_p,
-             EmissionState *state_p)
+emission_pop (Emission **emission_list_p,
+             Emission  *emission)
 {
-  Emission **loc = emission_list_p, *emission = *loc;
-  
-  while (emission->state_p != state_p)
-    {
-      loc = &emission->next;
-      emission = *loc;
-    }
-  *loc = emission->next;
-  g_generic_node_free (&g_emission_ts, emission);
+  Emission *node, *last = NULL;
+
+  for (node = *emission_list_p; node; last = node, node = last->next)
+    if (node == emission)
+      {
+       if (last)
+         last->next = node->next;
+       else
+         *emission_list_p = node->next;
+       return;
+      }
+  g_assert_not_reached ();
 }
 
 static inline Emission*
@@ -631,12 +656,37 @@ emission_find (Emission *emission_list,
   
   for (emission = emission_list; emission; emission = emission->next)
     if (emission->instance == instance &&
-       emission->signal_id == signal_id &&
-       emission->detail == detail)
+       emission->ihint.signal_id == signal_id &&
+       emission->ihint.detail == detail)
       return emission;
   return NULL;
 }
 
+static inline Emission*
+emission_find_innermost (gpointer instance)
+{
+  Emission *emission, *s = NULL, *c = NULL;
+  
+  for (emission = g_restart_emissions; emission; emission = emission->next)
+    if (emission->instance == instance)
+      {
+       s = emission;
+       break;
+      }
+  for (emission = g_recursive_emissions; emission; emission = emission->next)
+    if (emission->instance == instance)
+      {
+       c = emission;
+       break;
+      }
+  if (!s)
+    return c;
+  else if (!c)
+    return s;
+  else
+    return G_HAVE_GROWING_STACK ? MAX (c, s) : MIN (c, s);
+}
+
 static gint
 signal_key_cmp (gconstpointer node1,
                 gconstpointer node2)
@@ -652,26 +702,22 @@ signal_key_cmp (gconstpointer node1,
 void
 g_signal_init (void) /* sync with gtype.c */
 {
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   if (!g_n_signal_nodes)
     {
       /* handler_id_node_prepend() requires this */
       g_assert (sizeof (GList) == sizeof (HandlerMatch));
       
-      /* setup signal key array */
-      g_signal_key_bsa.cmp_func = signal_key_cmp;
-      g_signal_key_bsa.sizeof_node = sizeof (SignalKey);
-      g_signal_key_bsa.flags = G_BSEARCH_ALIGN_POWER2; /* alloc-only */
-      
       /* setup handler list binary searchable array hash table (in german, that'd be one word ;) */
       g_handler_list_bsa_ht = g_hash_table_new (g_direct_hash, NULL);
+      g_signal_key_bsa = g_bsearch_array_new (&g_signal_key_bconfig);
       
       /* invalid (0) signal_id */
       g_n_signal_nodes = 1;
       g_signal_nodes = g_renew (SignalNode*, g_signal_nodes, g_n_signal_nodes);
       g_signal_nodes[0] = NULL;
     }
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 }
 
 void
@@ -679,7 +725,7 @@ _g_signals_destroy (GType itype)
 {
   guint i;
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   for (i = 1; i < g_n_signal_nodes; i++)
     {
       SignalNode *node = g_signal_nodes[i];
@@ -689,14 +735,28 @@ _g_signals_destroy (GType itype)
           if (node->destroyed)
             g_warning (G_STRLOC ": signal \"%s\" of type `%s' already destroyed",
                        node->name,
-                       g_type_name (node->itype));
+                       type_debug_name (node->itype));
           else
            signal_destroy_R (node);
         }
     }
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 }
 
+/**
+ * g_signal_stop_emission:
+ * @instance: the object whose signal handlers you wish to stop.
+ * @signal_id: the signal identifier, as returned by g_signal_lookup().
+ * @detail: the detail which the signal was emitted with.
+ * 
+ * Stops a signal's current emission.
+ *
+ * This will prevent the default method from running, if the signal was
+ * %G_SIGNAL_RUN_LAST and you connected normally (i.e. without the "after" 
+ * flag).
+ *
+ * Prints a warning if used on a signal which isn't being emitted.
+ **/
 void
 g_signal_stop_emission (gpointer instance,
                         guint    signal_id,
@@ -707,12 +767,12 @@ g_signal_stop_emission (gpointer instance,
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (signal_id > 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (node && detail && !(node->flags & G_SIGNAL_DETAILED))
     {
       g_warning ("%s: signal id `%u' does not support detail (%u)", G_STRLOC, signal_id, detail);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return;
     }
   if (node && g_type_is_a (G_TYPE_FROM_INSTANCE (instance), node->itype))
@@ -722,11 +782,11 @@ g_signal_stop_emission (gpointer instance,
       
       if (emission)
         {
-          if (*emission->state_p == EMISSION_HOOK)
+          if (emission->state == EMISSION_HOOK)
             g_warning (G_STRLOC ": emission of signal \"%s\" for instance `%p' cannot be stopped from emission hook",
                        node->name, instance);
-          else if (*emission->state_p == EMISSION_RUN)
-            *emission->state_p = EMISSION_STOP;
+          else if (emission->state == EMISSION_RUN)
+            emission->state = EMISSION_STOP;
         }
       else
         g_warning (G_STRLOC ": no emission of signal \"%s\" to stop for instance `%p'",
@@ -734,7 +794,7 @@ g_signal_stop_emission (gpointer instance,
     }
   else
     g_warning ("%s: signal id `%u' is invalid for instance `%p'", G_STRLOC, signal_id, instance);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 }
 
 static void
@@ -746,20 +806,34 @@ signal_finalize_hook (GHookList *hook_list,
   if (destroy)
     {
       hook->destroy = NULL;
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       destroy (hook->data);
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
     }
 }
 
-guint
+/**
+ * g_signal_add_emission_hook:
+ * @signal_id: the signal identifier, as returned by g_signal_lookup().
+ * @detail: the detail on which to call the hook.
+ * @hook_func: a #GSignalEmissionHook function.
+ * @hook_data: user data for @hook_func.
+ * @data_destroy: a #GDestroyNotify for @hook_data.
+ * 
+ * Adds an emission hook for a signal, which will get called for any emission
+ * of that signal, independent of the instance.
+ * 
+ * Return value: the hook id, for later use with 
+ *               g_signal_remove_emission_hook().
+ **/
+gulong
 g_signal_add_emission_hook (guint               signal_id,
                            GQuark              detail,
                            GSignalEmissionHook hook_func,
                            gpointer            hook_data,
                            GDestroyNotify      data_destroy)
 {
-  static guint seq_hook_id = 1;
+  static gulong seq_hook_id = 1;
   SignalNode *node;
   GHook *hook;
   SignalHook *signal_hook;
@@ -767,18 +841,18 @@ g_signal_add_emission_hook (guint               signal_id,
   g_return_val_if_fail (signal_id > 0, 0);
   g_return_val_if_fail (hook_func != NULL, 0);
 
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (!node || node->destroyed || (node->flags & G_SIGNAL_NO_HOOKS))
     {
       g_warning ("%s: invalid signal id `%u'", G_STRLOC, signal_id);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   if (detail && !(node->flags & G_SIGNAL_DETAILED))
     {
       g_warning ("%s: signal id `%u' does not support detail (%u)", G_STRLOC, signal_id, detail);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   if (!node->emission_hooks)
@@ -789,34 +863,42 @@ g_signal_add_emission_hook (guint               signal_id,
     }
   hook = g_hook_alloc (node->emission_hooks);
   hook->data = hook_data;
-  hook->func = hook_func;
+  hook->func = (gpointer) hook_func;
   hook->destroy = data_destroy;
   signal_hook = SIGNAL_HOOK (hook);
   signal_hook->detail = detail;
   node->emission_hooks->seq_id = seq_hook_id;
   g_hook_append (node->emission_hooks, hook);
   seq_hook_id = node->emission_hooks->seq_id;
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 
   return hook->hook_id;
 }
 
+/**
+ * g_signal_remove_emission_hook:
+ * @signal_id: the id of the signal
+ * @hook_id: the id of the emission hook, as returned by 
+ *           g_signal_add_emission_hook()
+ * 
+ * Deletes an emission hook.
+ **/
 void
-g_signal_remove_emission_hook (guint signal_id,
-                              guint hook_id)
+g_signal_remove_emission_hook (guint  signal_id,
+                              gulong hook_id)
 {
   SignalNode *node;
 
   g_return_if_fail (signal_id > 0);
   g_return_if_fail (hook_id > 0);
 
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (!node || node->destroyed)
     g_warning ("%s: invalid signal id `%u'", G_STRLOC, signal_id);
   else if (!node->emission_hooks || !g_hook_destroy (node->emission_hooks, hook_id))
-    g_warning ("%s: signal \"%s\" had no hook (%u) to remove", G_STRLOC, node->name, hook_id);
-  G_UNLOCK (g_signal_mutex);
+    g_warning ("%s: signal \"%s\" had no hook (%lu) to remove", G_STRLOC, node->name, hook_id);
+  SIGNAL_UNLOCK ();
 }
 
 static inline guint
@@ -863,6 +945,20 @@ signal_parse_name (const gchar *name,
   return signal_id;
 }
 
+/**
+ * g_signal_parse_name:
+ * @detailed_signal: a string of the form "signal-name::detail".
+ * @itype: The interface/instance type that introduced "signal-name".
+ * @signal_id_p: Location to store the signal id.
+ * @detail_p: Location to store the detail quark.
+ * @force_detail_quark: %TRUE forces creation of a #GQuark for the detail.
+ * 
+ * Internal function to parse a signal name into its @signal_id
+ * and @detail quark.
+ * 
+ * Return value: Whether the signal name could successfully be parsed and
+ *               @signal_id_p and @detail_p contain valid return values.
+ **/
 gboolean
 g_signal_parse_name (const gchar *detailed_signal,
                     GType        itype,
@@ -877,9 +973,9 @@ g_signal_parse_name (const gchar *detailed_signal,
   g_return_val_if_fail (detailed_signal != NULL, FALSE);
   g_return_val_if_fail (G_TYPE_IS_INSTANTIATABLE (itype) || G_TYPE_IS_INTERFACE (itype), FALSE);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   signal_id = signal_parse_name (detailed_signal, itype, &detail, force_detail_quark);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 
   node = signal_id ? LOOKUP_SIGNAL_NODE (signal_id) : NULL;
   if (!node || node->destroyed ||
@@ -894,61 +990,115 @@ g_signal_parse_name (const gchar *detailed_signal,
   return TRUE;
 }
 
+/**
+ * g_signal_stop_emission_by_name:
+ * @instance: the object whose signal handlers you wish to stop.
+ * @detailed_signal: a string of the form "signal-name::detail".
+ * 
+ * Stops a signal's current emission.
+ *
+ * This is just like g_signal_stop_emission() except it will look up the 
+ * signal id for you.
+ **/
+void
+g_signal_stop_emission_by_name (gpointer     instance,
+                               const gchar *detailed_signal)
+{
+  guint signal_id;
+  GQuark detail = 0;
+  GType itype;
+  
+  g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
+  g_return_if_fail (detailed_signal != NULL);
+  
+  SIGNAL_LOCK ();
+  itype = G_TYPE_FROM_INSTANCE (instance);
+  signal_id = signal_parse_name (detailed_signal, itype, &detail, TRUE);
+  if (signal_id)
+    {
+      SignalNode *node = LOOKUP_SIGNAL_NODE (signal_id);
+      
+      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))
+       g_warning ("%s: signal `%s' is invalid for instance `%p'", G_STRLOC, detailed_signal, instance);
+      else
+       {
+         Emission *emission_list = node->flags & G_SIGNAL_NO_RECURSE ? g_restart_emissions : g_recursive_emissions;
+         Emission *emission = emission_find (emission_list, signal_id, detail, instance);
+         
+         if (emission)
+           {
+             if (emission->state == EMISSION_HOOK)
+               g_warning (G_STRLOC ": emission of signal \"%s\" for instance `%p' cannot be stopped from emission hook",
+                          node->name, instance);
+             else if (emission->state == EMISSION_RUN)
+               emission->state = EMISSION_STOP;
+           }
+         else
+           g_warning (G_STRLOC ": no emission of signal \"%s\" to stop for instance `%p'",
+                      node->name, instance);
+       }
+    }
+  else
+    g_warning ("%s: signal `%s' is invalid for instance `%p'", G_STRLOC, detailed_signal, instance);
+  SIGNAL_UNLOCK ();
+}
+
+/**
+ * g_signal_lookup:
+ * @name: the signal's name.
+ * @itype: the type that the signal operates on.
+ * 
+ * Given the name of the signal and the type of object it connects to, gets 
+ * the signal's identifying integer. Emitting the signal by number is 
+ * somewhat faster than using the name each time.
+ *
+ * Also tries the ancestors of the given type.
+ *
+ * See g_signal_new() for details on allowed signal names.
+ * 
+ * Return value: the signal's identifying number, or 0 if no signal was found.
+ **/
 guint
 g_signal_lookup (const gchar *name,
                  GType        itype)
 {
   guint signal_id;
-  
   g_return_val_if_fail (name != NULL, 0);
   g_return_val_if_fail (G_TYPE_IS_INSTANTIATABLE (itype) || G_TYPE_IS_INTERFACE (itype), 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   signal_id = signal_id_lookup (g_quark_try_string (name), itype);
-  G_UNLOCK (g_signal_mutex);
-  
-  return signal_id;
-}
-
-G_CONST_RETURN gchar*
-g_signal_name (guint signal_id)
-{
-  SignalNode *node;
-  gchar *name;
-  
-  G_LOCK (g_signal_mutex);
-  node = LOOKUP_SIGNAL_NODE (signal_id);
-  name = node ? node->name : NULL;
-  G_UNLOCK (g_signal_mutex);
-  
-  return name;
-}
-
-void
-g_signal_query (guint         signal_id,
-               GSignalQuery *query)
-{
-  SignalNode *node;
-  
-  g_return_if_fail (query != NULL);
-  
-  G_LOCK (g_signal_mutex);
-  node = LOOKUP_SIGNAL_NODE (signal_id);
-  if (!node || node->destroyed)
-    query->signal_id = 0;
-  else
+  SIGNAL_UNLOCK ();
+  if (!signal_id)
     {
-      query->signal_id = node->signal_id;
-      query->signal_name = node->name;
-      query->itype = node->itype;
-      query->signal_flags = node->flags;
-      query->return_type = node->return_type;
-      query->n_params = node->n_params;
-      query->param_types = node->param_types;
+      /* give elaborate warnings */
+      if (!g_type_name (itype))
+       g_warning (G_STRLOC ": unable to lookup signal \"%s\" for invalid type id `%lu'",
+                  name, itype);
+      else if (!G_TYPE_IS_INSTANTIATABLE (itype))
+       g_warning (G_STRLOC ": unable to lookup signal \"%s\" for non instantiatable type `%s'",
+                  name, g_type_name (itype));
+      else if (!g_type_class_peek (itype))
+       g_warning (G_STRLOC ": unable to lookup signal \"%s\" of unloaded type `%s'",
+                  name, g_type_name (itype));
     }
-  G_UNLOCK (g_signal_mutex);
+  
+  return signal_id;
 }
 
+/**
+ * g_signal_list_ids:
+ * @itype: Instance or interface type.
+ * @n_ids: Location to store the number of signal ids for @itype.
+ * 
+ * Lists the signals by id that a certain instance or interface type
+ * created. Further information about the signals can be acquired through
+ * g_signal_query().
+ * 
+ * Return value: Newly allocated array of signal IDs.
+ **/
 guint*
 g_signal_list_ids (GType  itype,
                   guint *n_ids)
@@ -961,10 +1111,9 @@ g_signal_list_ids (GType  itype,
   g_return_val_if_fail (G_TYPE_IS_INSTANTIATABLE (itype) || G_TYPE_IS_INTERFACE (itype), NULL);
   g_return_val_if_fail (n_ids != NULL, NULL);
   
-  G_LOCK (g_signal_mutex);
-  
-  keys = g_signal_key_bsa.nodes;
-  n_nodes  = g_signal_key_bsa.n_nodes;
+  SIGNAL_LOCK ();
+  keys = G_BSEARCH_ARRAY_NODES (g_signal_key_bsa);
+  n_nodes = g_signal_key_bsa->n_nodes;
   result = g_array_new (FALSE, FALSE, sizeof (guint));
   
   for (i = 0; i < n_nodes; i++)
@@ -978,59 +1127,129 @@ g_signal_list_ids (GType  itype,
        if (!strchr (name, '_'))
          g_array_append_val (result, keys[i].signal_id);
       }
-  
   *n_ids = result->len;
+  SIGNAL_UNLOCK ();
+  if (!n_nodes)
+    {
+      /* give elaborate warnings */
+      if (!g_type_name (itype))
+       g_warning (G_STRLOC ": unable to list signals for invalid type id `%lu'",
+                  itype);
+      else if (!G_TYPE_IS_INSTANTIATABLE (itype))
+       g_warning (G_STRLOC ": unable to list signals of non instantiatable type `%s'",
+                  g_type_name (itype));
+      else if (!g_type_class_peek (itype))
+       g_warning (G_STRLOC ": unable to list signals of unloaded type `%s'",
+                  g_type_name (itype));
+    }
   
-  G_UNLOCK (g_signal_mutex);
-  
-  return (guint *) g_array_free (result, FALSE);
+  return (guint*) g_array_free (result, FALSE);
 }
 
-guint
-g_signal_new_valist (const gchar       *signal_name,
-                     GType              itype,
-                     GSignalFlags       signal_flags,
-                     GClosure          *class_closure,
-                     GSignalAccumulator accumulator,
-                    gpointer           accu_data,
-                     GSignalCMarshaller c_marshaller,
-                     GType              return_type,
-                     guint              n_params,
-                     va_list            args)
+/**
+ * g_signal_name:
+ * @signal_id: the signal's identifying number.
+ * 
+ * Given the signal's identifier, finds its name.
+ *
+ * Two different signals may have the same name, if they have differing types.
+ * 
+ * Return value: the signal name, or %NULL if the signal number was invalid.
+ **/
+G_CONST_RETURN gchar*
+g_signal_name (guint signal_id)
 {
-  GType *param_types;
-  guint i;
-  guint signal_id;
+  SignalNode *node;
+  gchar *name;
+  
+  SIGNAL_LOCK ();
+  node = LOOKUP_SIGNAL_NODE (signal_id);
+  name = node ? node->name : NULL;
+  SIGNAL_UNLOCK ();
+  
+  return name;
+}
 
-  if (n_params > 0)
+/**
+ * g_signal_query:
+ * @signal_id: The signal id of the signal to query information for.
+ * @query: A user provided structure that is filled in with constant
+ *         values upon success.
+ * 
+ * Queries the signal system for in-depth information about a
+ * specific signal. This function will fill in a user-provided
+ * structure to hold signal-specific information. If an invalid
+ * signal id is passed in, the @signal_id member of the #GSignalQuery
+ * is 0. All members filled into the #GSignalQuery structure should
+ * be considered constant and have to be left untouched.
+ **/
+void
+g_signal_query (guint         signal_id,
+               GSignalQuery *query)
+{
+  SignalNode *node;
+  
+  g_return_if_fail (query != NULL);
+  
+  SIGNAL_LOCK ();
+  node = LOOKUP_SIGNAL_NODE (signal_id);
+  if (!node || node->destroyed)
+    query->signal_id = 0;
+  else
     {
-      param_types = g_new (GType, n_params);
-
-      for (i = 0; i < n_params; i++)
-       param_types[i] = va_arg (args, GType);
+      query->signal_id = node->signal_id;
+      query->signal_name = node->name;
+      query->itype = node->itype;
+      query->signal_flags = node->flags;
+      query->return_type = node->return_type;
+      query->n_params = node->n_params;
+      query->param_types = node->param_types;
     }
-  else
-    param_types = NULL;
-
-  signal_id = g_signal_newv (signal_name, itype, signal_flags,
-                            class_closure, accumulator, accu_data, c_marshaller,
-                            return_type, n_params, param_types);
-  g_free (param_types);
-
-  return signal_id;
+  SIGNAL_UNLOCK ();
 }
 
+/**
+ * g_signal_new:
+ * @signal_name: the name for the signal
+ * @itype: the type this signal pertains to. It will also pertain to 
+ *    types which are derived from this type.
+ * @signal_flags: a combination of #GSignalFlags specifying detail of when 
+ *    the default handler is to be invoked. You should at least specify 
+ *    %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST. 
+ * @class_offset: The offset of the function pointer in the class structure 
+ *    for this type. Used to invoke a class method generically.
+ * @accumulator: the accumulator for this signal; may be %NULL.
+ * @accu_data: user data for the @accumulator.
+ * @c_marshaller: the function to translate arrays of parameter values to 
+ *    signal emissions into C language callback invocations.
+ * @return_type: the type of return value, or #G_TYPE_NONE for a signal 
+ *    without a return value.
+ * @n_params: the number of parameter types to follow.
+ * @Varargs: a list of types, one for each parameter.
+ * 
+ * Creates a new signal. (This is usually done in the class initializer.)
+ *
+ * A signal name consists of segments consisting of ASCII letters and
+ * digits, separated by either the '-' or '_' character. The first
+ * character of a signal name must be a letter. Names which violate these
+ * rules lead to undefined behaviour of the GSignal system. 
+ *
+ * When registering a signal and looking up a signal, either separator can
+ * be used, but they cannot be mixed. 
+ * 
+ * Return value: the signal id
+ **/
 guint
-g_signal_newc (const gchar      *signal_name,
-               GType             itype,
-               GSignalFlags      signal_flags,
-               guint              class_offset,
-              GSignalAccumulator accumulator,
-              gpointer           accu_data,
-               GSignalCMarshaller c_marshaller,
-               GType             return_type,
-               guint             n_params,
-               ...)
+g_signal_new (const gchar       *signal_name,
+             GType               itype,
+             GSignalFlags        signal_flags,
+             guint               class_offset,
+             GSignalAccumulator  accumulator,
+             gpointer            accu_data,
+             GSignalCMarshaller  c_marshaller,
+             GType               return_type,
+             guint               n_params,
+             ...)
 {
   va_list args;
   guint signal_id;
@@ -1040,7 +1259,7 @@ g_signal_newc (const gchar         *signal_name,
   va_start (args, n_params);
 
   signal_id = g_signal_new_valist (signal_name, itype, signal_flags,
-                                   g_signal_type_cclosure_new (itype, class_offset),
+                                   class_offset ? g_signal_type_cclosure_new (itype, class_offset) : NULL,
                                   accumulator, accu_data, c_marshaller,
                                    return_type, n_params, args);
 
@@ -1049,6 +1268,89 @@ g_signal_newc (const gchar        *signal_name,
   return signal_id;
 }
 
+static inline ClassClosure*
+signal_find_class_closure (SignalNode *node,
+                          GType       itype)
+{
+  GBSearchArray *bsa = node->class_closure_bsa;
+  ClassClosure *cc;
+
+  if (bsa)
+    {
+      ClassClosure key;
+
+      /* cc->instance_type is 0 for default closure */
+      
+      key.instance_type = itype;
+      cc = g_bsearch_array_lookup (bsa, &g_class_closure_bconfig, &key);
+      while (!cc && key.instance_type)
+       {
+         key.instance_type = g_type_parent (key.instance_type);
+         cc = g_bsearch_array_lookup (bsa, &g_class_closure_bconfig, &key);
+       }
+    }
+  else
+    cc = NULL;
+  return cc;
+}
+
+static inline GClosure*
+signal_lookup_closure (SignalNode    *node,
+                      GTypeInstance *instance)
+{
+  ClassClosure *cc;
+
+  if (node->class_closure_bsa && node->class_closure_bsa->n_nodes == 1)
+    cc = G_BSEARCH_ARRAY_NODES (node->class_closure_bsa);
+  else
+    cc = signal_find_class_closure (node, G_TYPE_FROM_INSTANCE (instance));
+  return cc ? cc->closure : NULL;
+}
+
+static void
+signal_add_class_closure (SignalNode *node,
+                         GType       itype,
+                         GClosure   *closure)
+{
+  ClassClosure key;
+
+  if (!node->class_closure_bsa)
+    node->class_closure_bsa = g_bsearch_array_new (&g_class_closure_bconfig);
+  key.instance_type = itype;
+  key.closure = g_closure_ref (closure);
+  node->class_closure_bsa = g_bsearch_array_insert (node->class_closure_bsa,
+                                                   &g_class_closure_bconfig,
+                                                   &key,
+                                                   FALSE);
+  g_closure_sink (closure);
+  if (node->c_marshaller && closure && G_CLOSURE_NEEDS_MARSHAL (closure))
+    g_closure_set_marshal (closure, node->c_marshaller);
+}
+
+/**
+ * g_signal_newv:
+ * @signal_name: the name for the signal
+ * @itype: the type this signal pertains to. It will also pertain to 
+ *    types which are derived from this type.
+ * @signal_flags: a combination of #GSignalFlags specifying detail of when 
+ *    the default handler is to be invoked. You should at least specify 
+ *    %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST. 
+ * @class_closure: The closure to invoke on signal emission. 
+ * @accumulator: the accumulator for this signal; may be %NULL.
+ * @accu_data: user data for the @accumulator.
+ * @c_marshaller: the function to translate arrays of parameter values to 
+ *    signal emissions into C language callback invocations.
+ * @return_type: the type of return value, or #G_TYPE_NONE for a signal 
+ *    without a return value.
+ * @n_params: the length of @param_types.
+ * @param_types: an array types, one for each parameter.
+ * 
+ * Creates a new signal. (This is usually done in the class initializer.)
+ *
+ * See g_signal_new() for details on allowed signal names.
+ *
+ * Return value: the signal id
+ **/
 guint
 g_signal_newv (const gchar       *signal_name,
                GType              itype,
@@ -1069,15 +1371,16 @@ g_signal_newv (const gchar       *signal_name,
   g_return_val_if_fail (G_TYPE_IS_INSTANTIATABLE (itype) || G_TYPE_IS_INTERFACE (itype), 0);
   if (n_params)
     g_return_val_if_fail (param_types != NULL, 0);
+  g_return_val_if_fail ((return_type & G_SIGNAL_TYPE_STATIC_SCOPE) == 0, 0);
   if (return_type == (G_TYPE_NONE & ~G_SIGNAL_TYPE_STATIC_SCOPE))
     g_return_val_if_fail (accumulator == NULL, 0);
   if (!accumulator)
     g_return_val_if_fail (accu_data == NULL, 0);
 
   name = g_strdup (signal_name);
-  g_strdelimit (name, G_STR_DELIMITERS ":^", '_');  // FIXME do character checks like for types
+  g_strdelimit (name, G_STR_DELIMITERS ":^", '_');  /* FIXME do character checks like for types */
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   
   signal_id = signal_id_lookup (g_quark_try_string (name), itype);
   node = LOOKUP_SIGNAL_NODE (signal_id);
@@ -1085,37 +1388,46 @@ g_signal_newv (const gchar       *signal_name,
     {
       g_warning (G_STRLOC ": signal \"%s\" already exists in the `%s' %s",
                  name,
-                 g_type_name (node->itype),
+                 type_debug_name (node->itype),
                  G_TYPE_IS_INTERFACE (node->itype) ? "interface" : "class ancestry");
       g_free (name);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   if (node && node->itype != itype)
     {
       g_warning (G_STRLOC ": signal \"%s\" for type `%s' was previously created for type `%s'",
                  name,
-                 g_type_name (itype),
-                 g_type_name (node->itype));
+                 type_debug_name (itype),
+                 type_debug_name (node->itype));
       g_free (name);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   for (i = 0; i < n_params; i++)
     if (!G_TYPE_IS_VALUE (param_types[i] & ~G_SIGNAL_TYPE_STATIC_SCOPE))
       {
        g_warning (G_STRLOC ": parameter %d of type `%s' for signal \"%s::%s\" is not a value type",
-                  i + 1, g_type_name (param_types[i] & ~G_SIGNAL_TYPE_STATIC_SCOPE), g_type_name (itype), name);
+                  i + 1, type_debug_name (param_types[i]), type_debug_name (itype), name);
        g_free (name);
-       G_UNLOCK (g_signal_mutex);
+       SIGNAL_UNLOCK ();
        return 0;
       }
   if (return_type != G_TYPE_NONE && !G_TYPE_IS_VALUE (return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE))
     {
       g_warning (G_STRLOC ": return value of type `%s' for signal \"%s::%s\" is not a value type",
-                g_type_name (return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE), g_type_name (itype), name);
+                type_debug_name (return_type), type_debug_name (itype), name);
+      g_free (name);
+      SIGNAL_UNLOCK ();
+      return 0;
+    }
+  if (return_type != G_TYPE_NONE &&
+      (signal_flags & (G_SIGNAL_RUN_FIRST | G_SIGNAL_RUN_LAST | G_SIGNAL_RUN_CLEANUP)) == G_SIGNAL_RUN_FIRST)
+    {
+      g_warning (G_STRLOC ": signal \"%s::%s\" has return type `%s' and is only G_SIGNAL_RUN_FIRST",
+                type_debug_name (itype), name, type_debug_name (return_type));
       g_free (name);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   
@@ -1134,10 +1446,10 @@ g_signal_newv (const gchar       *signal_name,
       key.itype = itype;
       key.quark = g_quark_from_string (node->name);
       key.signal_id = signal_id;
-      g_bsearch_array_insert (&g_signal_key_bsa, &key, FALSE);
+      g_signal_key_bsa = g_bsearch_array_insert (g_signal_key_bsa, &g_signal_key_bconfig, &key, FALSE);
       g_strdelimit (node->name, "_", '-');
       key.quark = g_quark_from_static_string (node->name);
-      g_bsearch_array_insert (&g_signal_key_bsa, &key, FALSE);
+      g_signal_key_bsa = g_bsearch_array_insert (g_signal_key_bsa, &g_signal_key_bconfig, &key, FALSE);
     }
   node->destroyed = FALSE;
   
@@ -1146,9 +1458,7 @@ g_signal_newv (const gchar       *signal_name,
   node->n_params = n_params;
   node->param_types = g_memdup (param_types, sizeof (GType) * n_params);
   node->return_type = return_type;
-  node->class_closure = class_closure ? g_closure_ref (class_closure) : NULL;
-  if (class_closure)
-    g_closure_sink (class_closure);
+  node->class_closure_bsa = NULL;
   if (accumulator)
     {
       node->accumulator = g_new (SignalAccumulator, 1);
@@ -1159,9 +1469,68 @@ g_signal_newv (const gchar       *signal_name,
     node->accumulator = NULL;
   node->c_marshaller = c_marshaller;
   node->emission_hooks = NULL;
-  if (node->c_marshaller && class_closure && G_CLOSURE_NEEDS_MARSHAL (class_closure))
-    g_closure_set_marshal (class_closure, node->c_marshaller);
-  G_UNLOCK (g_signal_mutex);
+  if (class_closure)
+    signal_add_class_closure (node, 0, class_closure);
+  SIGNAL_UNLOCK ();
+
+  return signal_id;
+}
+
+/**
+ * g_signal_new_valist:
+ * @signal_name: the name for the signal
+ * @itype: the type this signal pertains to. It will also pertain to 
+ *    types which are derived from this type.
+ * @signal_flags: a combination of #GSignalFlags specifying detail of when 
+ *    the default handler is to be invoked. You should at least specify 
+ *    %G_SIGNAL_RUN_FIRST or %G_SIGNAL_RUN_LAST. 
+ * @class_closure: The closure to invoke on signal emission. 
+ * @accumulator: the accumulator for this signal; may be %NULL.
+ * @accu_data: user data for the @accumulator.
+ * @c_marshaller: the function to translate arrays of parameter values to 
+ *    signal emissions into C language callback invocations.
+ * @return_type: the type of return value, or #G_TYPE_NONE for a signal 
+ *    without a return value.
+ * @n_params: the number of parameter types in @args.
+ * @args: va_list of #GType, one for each parameter.
+ * 
+ * Creates a new signal. (This is usually done in the class initializer.)
+ *
+ * See g_signal_new() for details on allowed signal names.
+ *
+ * Return value: the signal id
+ **/
+guint
+g_signal_new_valist (const gchar       *signal_name,
+                     GType              itype,
+                     GSignalFlags       signal_flags,
+                     GClosure          *class_closure,
+                     GSignalAccumulator accumulator,
+                    gpointer           accu_data,
+                     GSignalCMarshaller c_marshaller,
+                     GType              return_type,
+                     guint              n_params,
+                     va_list            args)
+{
+  GType *param_types;
+  guint i;
+  guint signal_id;
+
+  if (n_params > 0)
+    {
+      param_types = g_new (GType, n_params);
+
+      for (i = 0; i < n_params; i++)
+       param_types[i] = va_arg (args, GType);
+    }
+  else
+    param_types = NULL;
+
+  signal_id = g_signal_newv (signal_name, itype, signal_flags,
+                            class_closure, accumulator, accu_data, c_marshaller,
+                            return_type, n_params, param_types);
+  g_free (param_types);
+
   return signal_id;
 }
 
@@ -1169,14 +1538,14 @@ static void
 signal_destroy_R (SignalNode *signal_node)
 {
   SignalNode node = *signal_node;
-  
+
   signal_node->destroyed = TRUE;
   
   /* reentrancy caution, zero out real contents first */
   signal_node->n_params = 0;
   signal_node->param_types = NULL;
   signal_node->return_type = 0;
-  signal_node->class_closure = NULL;
+  signal_node->class_closure_bsa = NULL;
   signal_node->accumulator = NULL;
   signal_node->c_marshaller = NULL;
   signal_node->emission_hooks = NULL;
@@ -1188,7 +1557,7 @@ signal_destroy_R (SignalNode *signal_node)
     
     for (emission = (node.flags & G_SIGNAL_NO_RECURSE) ? g_restart_emissions : g_recursive_emissions;
          emission; emission = emission->next)
-      if (emission->signal_id == node.signal_id)
+      if (emission->ihint.signal_id == node.signal_id)
         g_critical (G_STRLOC ": signal \"%s\" being destroyed is currently in emission (instance `%p')",
                     node.name, emission->instance);
   }
@@ -1196,19 +1565,173 @@ signal_destroy_R (SignalNode *signal_node)
   
   /* free contents that need to
    */
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
   g_free (node.param_types);
-  g_closure_unref (node.class_closure);
+  if (node.class_closure_bsa)
+    {
+      guint i;
+
+      for (i = 0; i < node.class_closure_bsa->n_nodes; i++)
+       {
+         ClassClosure *cc = g_bsearch_array_get_nth (node.class_closure_bsa, &g_class_closure_bconfig, i);
+
+         g_closure_unref (cc->closure);
+       }
+      g_bsearch_array_destroy (node.class_closure_bsa, &g_class_closure_bconfig);
+    }
   g_free (node.accumulator);
   if (node.emission_hooks)
     {
       g_hook_list_clear (node.emission_hooks);
       g_free (node.emission_hooks);
     }
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
 }
 
-guint
+/**
+ * g_signal_override_class_closure:
+ * @signal_id: the signal id 
+ * @instance_type: the instance type on which to override the class closure 
+ *                 for the signal. 
+ * @class_closure: the closure. 
+ * 
+ * Overrides the class closure (i.e. the default handler) for the given signal
+ * for emissions on instances of @instance_type. @instance_type must be derived
+ * from the type to which the signal belongs.
+ **/
+void
+g_signal_override_class_closure (guint     signal_id,
+                                GType     instance_type,
+                                GClosure *class_closure)
+{
+  SignalNode *node;
+  
+  g_return_if_fail (signal_id > 0);
+  g_return_if_fail (class_closure != NULL);
+  
+  SIGNAL_LOCK ();
+  node = LOOKUP_SIGNAL_NODE (signal_id);
+  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
+    {
+      ClassClosure *cc = signal_find_class_closure (node, instance_type);
+      
+      if (cc && cc->instance_type == instance_type)
+       g_warning ("%s: type `%s' is already overridden for signal id `%u'", G_STRLOC, type_debug_name (instance_type), signal_id);
+      else
+       signal_add_class_closure (node, instance_type, class_closure);
+    }
+  SIGNAL_UNLOCK ();
+}
+
+/**
+ * g_signal_chain_from_overridden:
+ * @instance_and_params:  the argument list of the signal emission. The first 
+ *      element in the array is a #GValue for the instance the signal is 
+ *      being emitted on. The rest are any arguments to be passed to the 
+ *      signal.  
+ * @return_value: Location for the return value. 
+ * 
+ * Calls the original class closure of a signal. This function should only
+ * be called from an overridden class closure; see 
+ * g_signal_override_class_closure().
+ **/
+void
+g_signal_chain_from_overridden (const GValue *instance_and_params,
+                               GValue       *return_value)
+{
+  GType chain_type = 0, restore_type = 0;
+  Emission *emission = NULL;
+  GClosure *closure = NULL;
+  guint n_params = 0;
+  gpointer instance;
+  
+  g_return_if_fail (instance_and_params != NULL);
+  instance = g_value_peek_pointer (instance_and_params);
+  g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
+  
+  SIGNAL_LOCK ();
+  emission = emission_find_innermost (instance);
+  if (emission)
+    {
+      SignalNode *node = LOOKUP_SIGNAL_NODE (emission->ihint.signal_id);
+      
+      g_assert (node != NULL); /* paranoid */
+      
+      /* we should probably do the same parameter checks as g_signal_emit() here.
+       */
+      if (emission->chain_type != G_TYPE_NONE)
+       {
+         ClassClosure *cc = signal_find_class_closure (node, emission->chain_type);
+         
+         g_assert (cc != NULL);        /* closure currently in call stack */
+
+         n_params = node->n_params;
+         restore_type = cc->instance_type;
+         cc = signal_find_class_closure (node, g_type_parent (cc->instance_type));
+         if (cc && cc->instance_type != restore_type)
+           {
+             closure = cc->closure;
+             chain_type = cc->instance_type;
+           }
+       }
+      else
+       g_warning ("%s: signal id `%u' cannot be chained from current emission stage for instance `%p'", G_STRLOC, node->signal_id, instance);
+    }
+  else
+    g_warning ("%s: no signal is currently being emitted for instance `%p'", G_STRLOC, instance);
+  if (closure)
+    {
+      emission->chain_type = chain_type;
+      SIGNAL_UNLOCK ();
+      g_closure_invoke (closure,
+                       return_value,
+                       n_params + 1,
+                       instance_and_params,
+                       &emission->ihint);
+      SIGNAL_LOCK ();
+      emission->chain_type = restore_type;
+    }
+  SIGNAL_UNLOCK ();
+}
+
+/**
+ * g_signal_get_invocation_hint:
+ * @instance: the instance to query
+ * 
+ * Returns the invocation hint of the innermost signal emission of instance. 
+ * 
+ * Return value: the invocation hint of the innermost signal emission.
+ **/
+GSignalInvocationHint*
+g_signal_get_invocation_hint (gpointer instance)
+{
+  Emission *emission = NULL;
+  
+  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), NULL);
+
+  SIGNAL_LOCK ();
+  emission = emission_find_innermost (instance);
+  SIGNAL_UNLOCK ();
+  
+  return emission ? &emission->ihint : NULL;
+}
+
+/**
+ * g_signal_connect_closure_by_id:
+ * @instance: the instance to connect to.
+ * @signal_id: the id of the signal.
+ * @detail: the detail.
+ * @closure: the closure to connect.
+ * @after: whether the handler should be called before or after the 
+ *         default handler of the signal.
+ * 
+ * Connects a closure to a signal for a particular object.
+ *
+ * Return value: the handler id 
+ **/
+gulong
 g_signal_connect_closure_by_id (gpointer  instance,
                                guint     signal_id,
                                GQuark    detail,
@@ -1216,13 +1739,13 @@ g_signal_connect_closure_by_id (gpointer  instance,
                                gboolean  after)
 {
   SignalNode *node;
-  guint handler_id = 0;
+  gulong handler_seq_no = 0;
   
   g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
   g_return_val_if_fail (signal_id > 0, 0);
   g_return_val_if_fail (closure != NULL, 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (node)
     {
@@ -1234,7 +1757,7 @@ g_signal_connect_closure_by_id (gpointer  instance,
        {
          Handler *handler = handler_new (after);
          
-         handler_id = handler->id;
+         handler_seq_no = handler->sequential_number;
          handler->detail = detail;
          handler->closure = g_closure_ref (closure);
          g_closure_sink (closure);
@@ -1245,18 +1768,31 @@ g_signal_connect_closure_by_id (gpointer  instance,
     }
   else
     g_warning ("%s: signal id `%u' is invalid for instance `%p'", G_STRLOC, signal_id, instance);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
   
-  return handler_id;
+  return handler_seq_no;
 }
 
-guint
+/**
+ * g_signal_connect_closure:
+ * @instance: the instance to connect to.
+ * @detailed_signal: a string of the form "signal-name::detail".
+ * @closure: the closure to connect.
+ * @after: whether the handler should be called before or after the 
+ *         default handler of the signal.
+ * 
+ * Connects a closure to a signal for a particular object.
+ *
+ * Return value: the handler id 
+ **/
+gulong
 g_signal_connect_closure (gpointer     instance,
                          const gchar *detailed_signal,
                          GClosure    *closure,
                          gboolean     after)
 {
-  guint signal_id, handler_id = 0;
+  guint signal_id;
+  gulong handler_seq_no = 0;
   GQuark detail = 0;
   GType itype;
 
@@ -1264,7 +1800,7 @@ g_signal_connect_closure (gpointer     instance,
   g_return_val_if_fail (detailed_signal != NULL, 0);
   g_return_val_if_fail (closure != NULL, 0);
 
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   itype = G_TYPE_FROM_INSTANCE (instance);
   signal_id = signal_parse_name (detailed_signal, itype, &detail, TRUE);
   if (signal_id)
@@ -1279,7 +1815,7 @@ g_signal_connect_closure (gpointer     instance,
        {
          Handler *handler = handler_new (after);
 
-         handler_id = handler->id;
+         handler_seq_no = handler->sequential_number;
          handler->detail = detail;
          handler->closure = g_closure_ref (closure);
          g_closure_sink (closure);
@@ -1290,29 +1826,46 @@ g_signal_connect_closure (gpointer     instance,
     }
   else
     g_warning ("%s: signal `%s' is invalid for instance `%p'", G_STRLOC, detailed_signal, instance);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 
-  return handler_id;
+  return handler_seq_no;
 }
 
-guint
+/**
+ * g_signal_connect_data:
+ * @instance: the instance to connect to.
+ * @detailed_signal: a string of the form "signal-name::detail".
+ * @c_handler: the #GCallback to connect.
+ * @data: data to pass to @c_handler calls. 
+ * @destroy_data: a #GDestroyNotify for @data.
+ * @connect_flags: a combination of #GConnectFlags.
+ * 
+ * Connects a #GCallback function to a signal for a particular object.
+ * 
+ * Return value: the handler id 
+ **/
+gulong
 g_signal_connect_data (gpointer       instance,
                       const gchar   *detailed_signal,
                       GCallback      c_handler,
                       gpointer       data,
                       GClosureNotify destroy_data,
-                      gboolean       swapped,
-                      gboolean       after)
+                      GConnectFlags  connect_flags)
 {
-  guint signal_id, handler_id = 0;
+  guint signal_id;
+  gulong handler_seq_no = 0;
   GQuark detail = 0;
   GType itype;
-
+  gboolean swapped, after;
+  
   g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
   g_return_val_if_fail (detailed_signal != NULL, 0);
   g_return_val_if_fail (c_handler != NULL, 0);
 
-  G_LOCK (g_signal_mutex);
+  swapped = (connect_flags & G_CONNECT_SWAPPED) != FALSE;
+  after = (connect_flags & G_CONNECT_AFTER) != FALSE;
+
+  SIGNAL_LOCK ();
   itype = G_TYPE_FROM_INSTANCE (instance);
   signal_id = signal_parse_name (detailed_signal, itype, &detail, TRUE);
   if (signal_id)
@@ -1327,7 +1880,7 @@ g_signal_connect_data (gpointer       instance,
        {
          Handler *handler = handler_new (after);
 
-         handler_id = handler->id;
+         handler_seq_no = handler->sequential_number;
          handler->detail = detail;
          handler->closure = g_closure_ref ((swapped ? g_cclosure_new_swap : g_cclosure_new) (c_handler, data, destroy_data));
          g_closure_sink (handler->closure);
@@ -1338,21 +1891,35 @@ g_signal_connect_data (gpointer       instance,
     }
   else
     g_warning ("%s: signal `%s' is invalid for instance `%p'", G_STRLOC, detailed_signal, instance);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 
-  return handler_id;
+  return handler_seq_no;
 }
 
+/**
+ * g_signal_handler_block:
+ * @instance: The instance to block the signal handler of.
+ * @handler_id: Handler id of the handler to be blocked.
+ * 
+ * Blocks a handler of an instance so it will not be called during 
+ * any signal emissions unless it is unblocked again. Thus "blocking" 
+ * a signal handler means to temporarily deactive it, a signal handler 
+ * has to be unblocked exactly the same amount of times it has been 
+ * blocked before to become active again.
+ *
+ * The @handler_id has to be a valid signal handler id, connected to a 
+ * signal of @instance.
+ **/
 void
 g_signal_handler_block (gpointer instance,
-                        guint    handler_id)
+                        gulong   handler_id)
 {
   Handler *handler;
   
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (handler_id > 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   handler = handler_lookup (instance, handler_id, NULL);
   if (handler)
     {
@@ -1360,40 +1927,70 @@ g_signal_handler_block (gpointer instance,
       if (handler->block_count >= HANDLER_MAX_BLOCK_COUNT - 1)
         g_error (G_STRLOC ": handler block_count overflow, %s", REPORT_BUG);
 #endif
-      
       handler->block_count += 1;
     }
   else
-    g_warning ("%s: instance `%p' has no handler with id `%u'", G_STRLOC, instance, handler_id);
-  G_UNLOCK (g_signal_mutex);
+    g_warning ("%s: instance `%p' has no handler with id `%lu'", G_STRLOC, instance, handler_id);
+  SIGNAL_UNLOCK ();
 }
 
+/**
+ * g_signal_handler_unblock:
+ * @instance: The instance to unblock the signal handler of.
+ * @handler_id: Handler id of the handler to be unblocked.
+ * 
+ * Undoes the effect of a previous g_signal_handler_block() call. 
+ * A blocked handler is skipped during signal emissions and will not be 
+ * invoked, unblocking it (for exactly the amount of times it has been 
+ * blocked before) reverts its "blocked" state, so the handler will be 
+ * recognized by the signal system and is called upon future or currently
+ * ongoing signal emissions (since the order in which handlers are
+ * called during signal emissions is deterministic, whether the
+ * unblocked handler in question is called as part of a currently
+ * ongoing emission depends on how far that emission has proceeded
+ * yet).
+ *
+ * The @handler_id has to be a valid id of a signal handler that is 
+ * connected to a signal of @instance and is currently blocked.
+ **/
 void
 g_signal_handler_unblock (gpointer instance,
-                          guint    handler_id)
+                          gulong   handler_id)
 {
   Handler *handler;
   
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (handler_id > 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   handler = handler_lookup (instance, handler_id, NULL);
   if (handler)
     {
       if (handler->block_count)
         handler->block_count -= 1;
       else
-        g_warning (G_STRLOC ": handler `%u' of instance `%p' is not blocked", handler_id, instance);
+        g_warning (G_STRLOC ": handler `%lu' of instance `%p' is not blocked", handler_id, instance);
     }
   else
-    g_warning ("%s: instance `%p' has no handler with id `%u'", G_STRLOC, instance, handler_id);
-  G_UNLOCK (g_signal_mutex);
+    g_warning ("%s: instance `%p' has no handler with id `%lu'", G_STRLOC, instance, handler_id);
+  SIGNAL_UNLOCK ();
 }
 
+/**
+ * g_signal_handler_disconnect:
+ * @instance: The instance to remove the signal handler from. 
+ * @handler_id: Handler id of the handler to be disconnected.
+ * 
+ * Disconnects a handler from an instance so it will not be called during 
+ * any future or currently ongoing emissions of the signal it has been 
+ * connected to. The @handler_id becomes invalid and may be reused.
+ *
+ * The @handler_id has to be a valid signal handler id, connected to a 
+ * signal of @instance.
+ **/
 void
 g_signal_handler_disconnect (gpointer instance,
-                             guint    handler_id)
+                             gulong   handler_id)
 {
   Handler *handler;
   guint signal_id;
@@ -1401,19 +1998,56 @@ g_signal_handler_disconnect (gpointer instance,
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (handler_id > 0);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   handler = handler_lookup (instance, handler_id, &signal_id);
   if (handler)
     {
-      handler->id = 0;
+      handler->sequential_number = 0;
       handler->block_count = 1;
       handler_unref_R (signal_id, instance, handler);
     }
   else
-    g_warning ("%s: instance `%p' has no handler with id `%u'", G_STRLOC, instance, handler_id);
-  G_UNLOCK (g_signal_mutex);
+    g_warning ("%s: instance `%p' has no handler with id `%lu'", G_STRLOC, instance, handler_id);
+  SIGNAL_UNLOCK ();
+}
+
+/**
+ * g_signal_handler_is_connected:
+ * @instance: The instance where a signal handler is sought.
+ * @handler_id: the handler id.
+ * 
+ * Returns whether @handler_id is the id of a handler connected to @instance.
+ * 
+ * Return value: whether @handler_id identifies a handler connected to 
+ *               @instance.
+ **/
+gboolean
+g_signal_handler_is_connected (gpointer instance,
+                              gulong   handler_id)
+{
+  Handler *handler;
+  gboolean connected;
+
+  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), FALSE);
+  g_return_val_if_fail (handler_id > 0, FALSE);
+
+  SIGNAL_LOCK ();
+  handler = handler_lookup (instance, handler_id, NULL);
+  connected = handler != NULL;
+  SIGNAL_UNLOCK ();
+
+  return connected;
 }
 
+/**
+ * g_signal_handlers_destroy:
+ * @instance: The instance whose signal handlers are to be destroyed
+ * 
+ * Destroys all the signal handlers connected to an object. This is done 
+ * automatically when the object is destroyed.
+ *
+ * This function is labeled private.
+ **/
 void
 g_signal_handlers_destroy (gpointer instance)
 {
@@ -1421,7 +2055,7 @@ g_signal_handlers_destroy (gpointer instance)
   
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   hlbsa = g_hash_table_lookup (g_handler_list_bsa_ht, instance);
   if (hlbsa)
     {
@@ -1432,7 +2066,7 @@ g_signal_handlers_destroy (gpointer instance)
       
       for (i = 0; i < hlbsa->n_nodes; i++)
         {
-          HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, i);
+          HandlerList *hlist = g_bsearch_array_get_nth (hlbsa, &g_signal_hlbsa_bconfig, i);
           Handler *handler = hlist->handlers;
          
           while (handler)
@@ -1444,20 +2078,38 @@ g_signal_handlers_destroy (gpointer instance)
               /* cruel unlink, this works because _all_ handlers vanish */
               tmp->next = NULL;
               tmp->prev = tmp;
-              if (tmp->id)
+              if (tmp->sequential_number)
                {
-                 tmp->id = 0;
+                 tmp->sequential_number = 0;
                  handler_unref_R (0, NULL, tmp);
                }
             }
         }
-      g_free (hlbsa->nodes);
-      g_generic_node_free (&g_bsa_ts, hlbsa);
+      g_bsearch_array_destroy (hlbsa, &g_signal_hlbsa_bconfig);
     }
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 }
 
-guint
+/**
+ * g_signal_handler_find:
+ * @instance: The instance owning the signal handler to be found.
+ * @mask: Mask indicating which of @signal_id, @detail, @closure, @func 
+ *        and/or @data the handler has to match.
+ * @signal_id: Signal the handler has to be connected to.
+ * @detail: Signal detail the handler has to be connected to.
+ * @closure: The closure the handler will invoke.
+ * @func: The C closure callback of the handler (useless for non-C closures).
+ * @data: The closure data of the handler's closure.
+ * 
+ * Finds the first signal handler that matches certain selection criteria.
+ * The criteria mask is passed as an OR-ed combination of #GSignalMatchType
+ * flags, and the criteria values are passed as arguments.
+ * The match @mask has to be non-0 for successful matches.
+ * If no handler was found, 0 is returned.
+ * 
+ * Return value: A valid non-0 signal handler id for a successful match.
+ **/
+gulong
 g_signal_handler_find (gpointer         instance,
                        GSignalMatchType mask,
                        guint            signal_id,
@@ -1466,7 +2118,7 @@ g_signal_handler_find (gpointer         instance,
                        gpointer         func,
                        gpointer         data)
 {
-  guint handler_id = 0;
+  gulong handler_seq_no = 0;
   
   g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
   g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, 0);
@@ -1475,17 +2127,17 @@ g_signal_handler_find (gpointer         instance,
     {
       HandlerMatch *mlist;
       
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
       mlist = handlers_find (instance, mask, signal_id, detail, closure, func, data, TRUE);
       if (mlist)
        {
-         handler_id = mlist->handler->id;
+         handler_seq_no = mlist->handler->sequential_number;
          handler_match_free1_R (mlist, instance);
        }
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
     }
   
-  return handler_id;
+  return handler_seq_no;
 }
 
 static guint
@@ -1497,7 +2149,7 @@ signal_handlers_foreach_matched_R (gpointer         instance,
                                   gpointer         func,
                                   gpointer         data,
                                   void           (*callback) (gpointer instance,
-                                                              guint    handler_id))
+                                                              gulong   handler_seq_no))
 {
   HandlerMatch *mlist;
   guint n_handlers = 0;
@@ -1506,15 +2158,39 @@ signal_handlers_foreach_matched_R (gpointer         instance,
   while (mlist)
     {
       n_handlers++;
-      G_UNLOCK (g_signal_mutex);
-      callback (instance, mlist->handler->id);
-      G_LOCK (g_signal_mutex);
+      if (mlist->handler->sequential_number)
+       {
+         SIGNAL_UNLOCK ();
+         callback (instance, mlist->handler->sequential_number);
+         SIGNAL_LOCK ();
+       }
       mlist = handler_match_free1_R (mlist, instance);
     }
   
   return n_handlers;
 }
 
+/**
+ * g_signal_handlers_block_matched:
+ * @instance: The instance to block handlers from. 
+ * @mask: Mask indicating which of @signal_id, @detail, @closure, @func 
+ *        and/or @data the handlers have to match.
+ * @signal_id: Signal the handlers have to be connected to.
+ * @detail: Signal detail the handlers have to be connected to.
+ * @closure: The closure the handlers will invoke.
+ * @func: The C closure callback of the handlers (useless for non-C closures).
+ * @data: The closure data of the handlers' closures.
+ * 
+ * Blocks all handlers on an instance that match a certain selection criteria.
+ * The criteria mask is passed as an OR-ed combination of #GSignalMatchType 
+ * flags, and the criteria values are passed as arguments.
+ * Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
+ * or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
+ * If no handlers were found, 0 is returned, the number of blocked handlers
+ * otherwise.
+ * 
+ * Return value: The amount of handlers that got blocked.
+ **/
 guint
 g_signal_handlers_block_matched (gpointer         instance,
                                 GSignalMatchType mask,
@@ -1531,16 +2207,38 @@ g_signal_handlers_block_matched (gpointer         instance,
   
   if (mask & (G_SIGNAL_MATCH_CLOSURE | G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA))
     {
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
       n_handlers = signal_handlers_foreach_matched_R (instance, mask, signal_id, detail,
                                                      closure, func, data,
                                                      g_signal_handler_block);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
     }
   
   return n_handlers;
 }
 
+/**
+ * g_signal_handlers_unblock_matched:
+ * @instance: The instance to unblock handlers from.
+ * @mask: Mask indicating which of @signal_id, @detail, @closure, @func 
+ *        and/or @data the handlers have to match.
+ * @signal_id: Signal the handlers have to be connected to.
+ * @detail: Signal detail the handlers have to be connected to.
+ * @closure: The closure the handlers will invoke.
+ * @func: The C closure callback of the handlers (useless for non-C closures).
+ * @data: The closure data of the handlers' closures.
+ * 
+ * Unblocks all handlers on an instance that match a certain selection
+ * criteria. The criteria mask is passed as an OR-ed combination of
+ * #GSignalMatchType flags, and the criteria values are passed as arguments.
+ * Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
+ * or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
+ * If no handlers were found, 0 is returned, the number of unblocked handlers
+ * otherwise. The match criteria should not apply to any handlers that are
+ * not currently blocked.
+ * 
+ * Return value: The amount of handlers that got unblocked.
+ **/
 guint
 g_signal_handlers_unblock_matched (gpointer         instance,
                                   GSignalMatchType mask,
@@ -1557,16 +2255,37 @@ g_signal_handlers_unblock_matched (gpointer         instance,
   
   if (mask & (G_SIGNAL_MATCH_CLOSURE | G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA))
     {
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
       n_handlers = signal_handlers_foreach_matched_R (instance, mask, signal_id, detail,
                                                      closure, func, data,
                                                      g_signal_handler_unblock);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
     }
   
   return n_handlers;
 }
 
+/**
+ * g_signal_handlers_disconnect_matched:
+ * @instance: The instance to remove handlers from. 
+ * @mask: Mask indicating which of @signal_id, @detail, @closure, @func 
+ *        and/or @data the handlers have to match.
+ * @signal_id: Signal the handlers have to be connected to.
+ * @detail: Signal detail the handlers have to be connected to.
+ * @closure: The closure the handlers will invoke.
+ * @func: The C closure callback of the handlers (useless for non-C closures).
+ * @data: The closure data of the handlers' closures.
+ * 
+ * Disconnects all handlers on an instance that match a certain selection 
+ * criteria. The criteria mask is passed as an OR-ed combination of
+ * #GSignalMatchType flags, and the criteria values are passed as arguments.
+ * Passing at least one of the %G_SIGNAL_MATCH_CLOSURE, %G_SIGNAL_MATCH_FUNC
+ * or %G_SIGNAL_MATCH_DATA match flags is required for successful matches.
+ * If no handlers were found, 0 is returned, the number of disconnected 
+ * handlers otherwise.
+ * 
+ * Return value: The amount of handlers that got disconnected.
+ **/
 guint
 g_signal_handlers_disconnect_matched (gpointer         instance,
                                      GSignalMatchType mask,
@@ -1583,16 +2302,34 @@ g_signal_handlers_disconnect_matched (gpointer         instance,
   
   if (mask & (G_SIGNAL_MATCH_CLOSURE | G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA))
     {
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
       n_handlers = signal_handlers_foreach_matched_R (instance, mask, signal_id, detail,
                                                      closure, func, data,
                                                      g_signal_handler_disconnect);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
     }
   
   return n_handlers;
 }
 
+/**
+ * g_signal_has_handler_pending:
+ * @instance: the object whose signal handlers are sought.
+ * @signal_id: the signal id.
+ * @detail: the detail.
+ * @may_be_blocked: whether blocked handlers should count as match.
+ * 
+ * Returns whether there are any handlers connected to @instance for the
+ * given signal id and detail.
+ *
+ * One example of when you might use this is when the arguments to the 
+ * signal are difficult to compute. A class implementor may opt to not emit 
+ * the signal if no one is attached anyway, thus saving the cost of building
+ * the arguments.
+ * 
+ * Return value: %TRUE if a handler is connected to the signal, 
+ *               %FALSE otherwise.
+ **/
 gboolean
 g_signal_has_handler_pending (gpointer instance,
                              guint    signal_id,
@@ -1605,7 +2342,7 @@ g_signal_has_handler_pending (gpointer instance,
   g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), FALSE);
   g_return_val_if_fail (signal_id > 0, FALSE);
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   if (detail)
     {
       SignalNode *node = LOOKUP_SIGNAL_NODE (signal_id);
@@ -1613,7 +2350,7 @@ g_signal_has_handler_pending (gpointer instance,
       if (!(node->flags & G_SIGNAL_DETAILED))
        {
          g_warning ("%s: signal id `%u' does not support detail (%u)", G_STRLOC, signal_id, detail);
-         G_UNLOCK (g_signal_mutex);
+         SIGNAL_UNLOCK ();
          return FALSE;
        }
     }
@@ -1627,11 +2364,26 @@ g_signal_has_handler_pending (gpointer instance,
     }
   else
     has_pending = FALSE;
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
   
   return has_pending;
 }
 
+/**
+ * g_signal_emitv:
+ * @instance_and_params: argument list for the signal emission. The first 
+ *      element in the array is a #GValue for the instance the signal is 
+ *      being emitted on. The rest are any arguments to be passed to the 
+ *      signal.  
+ * @signal_id: the signal id 
+ * @detail: the detail
+ * @return_value: Location to store the return value of the signal emission.
+ * 
+ * Emits a signal. 
+ *
+ * Note that g_signal_emitv() doesn't change @return_value if no handlers are
+ * connected, in contrast to g_signal_emit() and g_signal_emit_valist().
+ **/
 void
 g_signal_emitv (const GValue *instance_and_params,
                guint         signal_id,
@@ -1641,7 +2393,9 @@ g_signal_emitv (const GValue *instance_and_params,
   const GValue *param_values;
   gpointer instance;
   SignalNode *node;
+#ifdef G_ENABLE_DEBUG
   guint i;
+#endif
   
   g_return_if_fail (instance_and_params != NULL);
   instance = g_value_peek_pointer (instance_and_params);
@@ -1650,19 +2404,19 @@ g_signal_emitv (const GValue *instance_and_params,
 
   param_values = instance_and_params + 1;
   
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (!node || !g_type_is_a (G_TYPE_FROM_INSTANCE (instance), node->itype))
     {
       g_warning ("%s: signal id `%u' is invalid for instance `%p'", G_STRLOC, signal_id, instance);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return;
     }
 #ifdef G_ENABLE_DEBUG
   if (detail && !(node->flags & G_SIGNAL_DETAILED))
     {
       g_warning ("%s: signal id `%u' does not support detail (%u)", G_STRLOC, signal_id, detail);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return;
     }
   for (i = 0; i < node->n_params; i++)
@@ -1670,11 +2424,11 @@ g_signal_emitv (const GValue *instance_and_params,
       {
        g_critical ("%s: value for `%s' parameter %u for signal \"%s\" is of type `%s'",
                    G_STRLOC,
-                   g_type_name (node->param_types[i] & ~G_SIGNAL_TYPE_STATIC_SCOPE),
+                   type_debug_name (node->param_types[i]),
                    i,
                    node->name,
                    G_VALUE_TYPE_NAME (param_values + i));
-       G_UNLOCK (g_signal_mutex);
+       SIGNAL_UNLOCK ();
        return;
       }
   if (node->return_type != G_TYPE_NONE)
@@ -1683,19 +2437,19 @@ g_signal_emitv (const GValue *instance_and_params,
        {
          g_critical ("%s: return value `%s' for signal \"%s\" is (NULL)",
                      G_STRLOC,
-                     g_type_name (node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE),
+                     type_debug_name (node->return_type),
                      node->name);
-         G_UNLOCK (g_signal_mutex);
+         SIGNAL_UNLOCK ();
          return;
        }
       else if (!node->accumulator && !G_TYPE_CHECK_VALUE_TYPE (return_value, node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE))
        {
          g_critical ("%s: return value `%s' for signal \"%s\" is of type `%s'",
                      G_STRLOC,
-                     g_type_name (node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE),
+                     type_debug_name (node->return_type),
                      node->name,
                      G_VALUE_TYPE_NAME (return_value));
-         G_UNLOCK (g_signal_mutex);
+         SIGNAL_UNLOCK ();
          return;
        }
     }
@@ -1703,10 +2457,24 @@ g_signal_emitv (const GValue *instance_and_params,
     return_value = NULL;
 #endif /* G_ENABLE_DEBUG */
 
-  signal_emit_R (node, detail, instance, return_value, instance_and_params);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
+  signal_emit_unlocked_R (node, detail, instance, return_value, instance_and_params);
 }
 
+/**
+ * g_signal_emit_valist:
+ * @instance: the instance the signal is being emitted on.
+ * @signal_id: the signal id 
+ * @detail: the detail
+ * @var_args: a list of parameters to be passed to the signal, followed by a
+ *            location for the return value. If the return type of the signal
+ *            is #G_TYPE_NONE, the return value location can be omitted.
+ * 
+ * Emits a signal. 
+ *
+ * Note that g_signal_emit_valist() resets the return value to the default
+ * if no handlers are connected, in contrast to g_signal_emitv().
+ **/
 void
 g_signal_emit_valist (gpointer instance,
                      guint    signal_id,
@@ -1714,30 +2482,33 @@ g_signal_emit_valist (gpointer instance,
                      va_list  var_args)
 {
   GValue *instance_and_params, stack_values[MAX_STACK_VALUES], *free_me = NULL;
+  GType signal_return_type;
   GValue *param_values;
   SignalNode *node;
-  guint i;
-
+  guint i, n_params;
+  
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (signal_id > 0);
 
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   node = LOOKUP_SIGNAL_NODE (signal_id);
   if (!node || !g_type_is_a (G_TYPE_FROM_INSTANCE (instance), node->itype))
     {
       g_warning ("%s: signal id `%u' is invalid for instance `%p'", G_STRLOC, signal_id, instance);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return;
     }
 #ifndef G_DISABLE_CHECKS
   if (detail && !(node->flags & G_SIGNAL_DETAILED))
     {
       g_warning ("%s: signal id `%u' does not support detail (%u)", G_STRLOC, signal_id, detail);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return;
     }
 #endif  /* !G_DISABLE_CHECKS */
 
+  n_params = node->n_params;
+  signal_return_type = node->return_type;
   if (node->n_params < MAX_STACK_VALUES)
     instance_and_params = stack_values;
   else
@@ -1749,12 +2520,15 @@ g_signal_emit_valist (gpointer instance,
   for (i = 0; i < node->n_params; i++)
     {
       gchar *error;
-
+      GType ptype = node->param_types[i] & ~G_SIGNAL_TYPE_STATIC_SCOPE;
+      gboolean static_scope = node->param_types[i] & G_SIGNAL_TYPE_STATIC_SCOPE;
+      
       param_values[i].g_type = 0;
-      g_value_init (param_values + i, node->param_types[i] & ~G_SIGNAL_TYPE_STATIC_SCOPE);
+      SIGNAL_UNLOCK ();
+      g_value_init (param_values + i, ptype);
       G_VALUE_COLLECT (param_values + i,
                       var_args,
-                      node->param_types[i] & G_SIGNAL_TYPE_STATIC_SCOPE ? G_VALUE_NOCOPY_CONTENTS : 0,
+                      static_scope ? G_VALUE_NOCOPY_CONTENTS : 0,
                       &error);
       if (error)
        {
@@ -1767,47 +2541,65 @@ g_signal_emit_valist (gpointer instance,
          while (i--)
            g_value_unset (param_values + i);
 
-         G_UNLOCK (g_signal_mutex);
          g_free (free_me);
          return;
        }
+      SIGNAL_LOCK ();
     }
+  SIGNAL_UNLOCK ();
   instance_and_params->g_type = 0;
   g_value_init (instance_and_params, G_TYPE_FROM_INSTANCE (instance));
   g_value_set_instance (instance_and_params, instance);
-  if (node->return_type == G_TYPE_NONE)
-    signal_emit_R (node, detail, instance, NULL, instance_and_params);
+  if (signal_return_type == G_TYPE_NONE)
+    signal_emit_unlocked_R (node, detail, instance, NULL, instance_and_params);
   else
     {
       GValue return_value = { 0, };
       gchar *error = NULL;
+      GType rtype = signal_return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE;
+      gboolean static_scope = signal_return_type & G_SIGNAL_TYPE_STATIC_SCOPE;
+      
+      g_value_init (&return_value, rtype);
 
-      g_value_init (&return_value, node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE);
-      if (signal_emit_R (node, detail, instance, &return_value, instance_and_params))
-       G_VALUE_LCOPY (&return_value,
-                      var_args,
-                      node->return_type & G_SIGNAL_TYPE_STATIC_SCOPE ? G_VALUE_NOCOPY_CONTENTS : 0,
-                      &error);
+      signal_emit_unlocked_R (node, detail, instance, &return_value, instance_and_params);
+
+      G_VALUE_LCOPY (&return_value,
+                    var_args,
+                    static_scope ? G_VALUE_NOCOPY_CONTENTS : 0,
+                    &error);
       if (!error)
        g_value_unset (&return_value);
       else
        {
          g_warning ("%s: %s", G_STRLOC, error);
          g_free (error);
-
+         
          /* we purposely leak the value here, it might not be
           * in a sane state if an error condition occoured
           */
        }
     }
-  for (i = 0; i < node->n_params; i++)
+  for (i = 0; i < n_params; i++)
     g_value_unset (param_values + i);
   g_value_unset (instance_and_params);
   if (free_me)
     g_free (free_me);
-  G_UNLOCK (g_signal_mutex);
 }
 
+/**
+ * g_signal_emit:
+ * @instance: the instance the signal is being emitted on.
+ * @signal_id: the signal id 
+ * @detail: the detail
+ * @Varargs: parameters to be passed to the signal, followed by a
+ *            location for the return value. If the return type of the signal
+ *            is #G_TYPE_NONE, the return value location can be omitted.
+ * 
+ * Emits a signal. 
+ *
+ * Note that g_signal_emit() resets the return value to the default
+ * if no handlers are connected, in contrast to g_signal_emitv().
+ **/
 void
 g_signal_emit (gpointer instance,
               guint    signal_id,
@@ -1821,6 +2613,19 @@ g_signal_emit (gpointer instance,
   va_end (var_args);
 }
 
+/**
+ * g_signal_emit_by_name:
+ * @instance: the instance the signal is being emitted on.
+ * @detailed_signal: a string of the form "signal-name::detail".
+ * @Varargs: parameters to be passed to the signal, followed by a
+ *           location for the return value. If the return type of the signal
+ *           is #G_TYPE_NONE, the return value location can be omitted.
+ * 
+ * Emits a signal. 
+ *
+ * Note that g_signal_emit_by_name() resets the return value to the default
+ * if no handlers are connected, in contrast to g_signal_emitv().
+ **/
 void
 g_signal_emit_by_name (gpointer     instance,
                       const gchar *detailed_signal,
@@ -1832,9 +2637,9 @@ g_signal_emit_by_name (gpointer     instance,
   g_return_if_fail (G_TYPE_CHECK_INSTANCE (instance));
   g_return_if_fail (detailed_signal != NULL);
 
-  G_LOCK (g_signal_mutex);
+  SIGNAL_LOCK ();
   signal_id = signal_parse_name (detailed_signal, G_TYPE_FROM_INSTANCE (instance), &detail, TRUE);
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 
   if (signal_id)
     {
@@ -1866,26 +2671,26 @@ accumulate (GSignalInvocationHint *ihint,
 }
 
 static gboolean
-signal_emit_R (SignalNode   *node,
-              GQuark        detail,
-              gpointer      instance,
-              GValue       *emission_return,
-              const GValue *instance_and_params)
+signal_emit_unlocked_R (SignalNode   *node,
+                       GQuark        detail,
+                       gpointer      instance,
+                       GValue       *emission_return,
+                       const GValue *instance_and_params)
 {
-  EmissionState emission_state = 0;
   SignalAccumulator *accumulator;
-  GSignalInvocationHint ihint;
+  Emission emission;
   GClosure *class_closure;
   HandlerList *hlist;
   Handler *handler_list = NULL;
   GValue *return_accu, accu = { 0, };
-  guint signal_id = node->signal_id;
+  guint signal_id;
+  gulong max_sequential_handler_number;
   gboolean return_value_altered = FALSE;
   
 #ifdef G_ENABLE_DEBUG
   IF_DEBUG (SIGNALS, g_trace_instance_signals == instance || g_trap_instance_signals == instance)
     {
-      g_message ("%s::%s(%u) emitted (instance=%p signal-node=%p)\n",
+      g_message ("%s::%s(%u) emitted (instance=%p, signal-node=%p)",
                 g_type_name (G_TYPE_FROM_INSTANCE (instance)),
                 node->name, detail,
                 instance, node);
@@ -1894,60 +2699,71 @@ signal_emit_R (SignalNode   *node,
     }
 #endif /* G_ENABLE_DEBUG */
   
+  SIGNAL_LOCK ();
+  signal_id = node->signal_id;
   if (node->flags & G_SIGNAL_NO_RECURSE)
     {
-      Emission *emission = emission_find (g_restart_emissions, signal_id, detail, instance);
+      Emission *node = emission_find (g_restart_emissions, signal_id, detail, instance);
       
-      if (emission)
+      if (node)
        {
-         *emission->state_p = EMISSION_RESTART;
+         node->state = EMISSION_RESTART;
+         SIGNAL_UNLOCK ();
          return return_value_altered;
        }
     }
-  ihint.signal_id = node->signal_id;
-  ihint.detail = detail;
   accumulator = node->accumulator;
   if (accumulator)
     {
+      SIGNAL_UNLOCK ();
       g_value_init (&accu, node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE);
       return_accu = &accu;
+      SIGNAL_LOCK ();
     }
   else
     return_accu = emission_return;
-  emission_push ((node->flags & G_SIGNAL_NO_RECURSE) ? &g_restart_emissions : &g_recursive_emissions,
-                signal_id, detail, instance, &emission_state);
-  class_closure = node->class_closure;
+  emission.instance = instance;
+  emission.ihint.signal_id = node->signal_id;
+  emission.ihint.detail = detail;
+  emission.ihint.run_type = 0;
+  emission.state = 0;
+  emission.chain_type = G_TYPE_NONE;
+  emission_push ((node->flags & G_SIGNAL_NO_RECURSE) ? &g_restart_emissions : &g_recursive_emissions, &emission);
+  class_closure = signal_lookup_closure (node, instance);
   
  EMIT_RESTART:
   
   if (handler_list)
     handler_unref_R (signal_id, instance, handler_list);
+  max_sequential_handler_number = g_handler_sequential_number;
   hlist = handler_list_lookup (signal_id, instance);
   handler_list = hlist ? hlist->handlers : NULL;
   if (handler_list)
     handler_ref (handler_list);
   
-  ihint.run_type = G_SIGNAL_RUN_FIRST;
+  emission.ihint.run_type = G_SIGNAL_RUN_FIRST;
   
   if ((node->flags & G_SIGNAL_RUN_FIRST) && class_closure)
     {
-      emission_state = EMISSION_RUN;
-      
-      G_UNLOCK (g_signal_mutex);
+      emission.state = EMISSION_RUN;
+
+      emission.chain_type = G_TYPE_FROM_INSTANCE (instance);
+      SIGNAL_UNLOCK ();
       g_closure_invoke (class_closure,
                        return_accu,
                        node->n_params + 1,
                        instance_and_params,
-                       &ihint);
-      if (!accumulate (&ihint, emission_return, &accu, accumulator) &&
-         emission_state == EMISSION_RUN)
-       emission_state = EMISSION_STOP;
-      G_LOCK (g_signal_mutex);
+                       &emission.ihint);
+      if (!accumulate (&emission.ihint, emission_return, &accu, accumulator) &&
+         emission.state == EMISSION_RUN)
+       emission.state = EMISSION_STOP;
+      SIGNAL_LOCK ();
+      emission.chain_type = G_TYPE_NONE;
       return_value_altered = TRUE;
       
-      if (emission_state == EMISSION_STOP)
+      if (emission.state == EMISSION_STOP)
        goto EMIT_CLEANUP;
-      else if (emission_state == EMISSION_RESTART)
+      else if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
@@ -1956,7 +2772,7 @@ signal_emit_R (SignalNode   *node,
       gboolean need_destroy, was_in_call, may_recurse = TRUE;
       GHook *hook;
 
-      emission_state = EMISSION_HOOK;
+      emission.state = EMISSION_HOOK;
       hook = g_hook_first_valid (node->emission_hooks, may_recurse);
       while (hook)
        {
@@ -1964,13 +2780,13 @@ signal_emit_R (SignalNode   *node,
          
          if (!signal_hook->detail || signal_hook->detail == detail)
            {
-             GSignalEmissionHook hook_func = hook->func;
+             GSignalEmissionHook hook_func = (GSignalEmissionHook) hook->func;
              
              was_in_call = G_HOOK_IN_CALL (hook);
              hook->flags |= G_HOOK_FLAG_IN_CALL;
-              G_UNLOCK (g_signal_mutex);
-             need_destroy = !hook_func (&ihint, node->n_params + 1, instance_and_params, hook->data);
-             G_LOCK (g_signal_mutex);
+              SIGNAL_UNLOCK ();
+             need_destroy = !hook_func (&emission.ihint, node->n_params + 1, instance_and_params, hook->data);
+             SIGNAL_LOCK ();
              if (!was_in_call)
                hook->flags &= ~G_HOOK_FLAG_IN_CALL;
              if (need_destroy)
@@ -1979,7 +2795,7 @@ signal_emit_R (SignalNode   *node,
          hook = g_hook_next_valid (node->emission_hooks, hook, may_recurse);
        }
       
-      if (emission_state == EMISSION_RESTART)
+      if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
@@ -1987,7 +2803,7 @@ signal_emit_R (SignalNode   *node,
     {
       Handler *handler = handler_list;
       
-      emission_state = EMISSION_RUN;
+      emission.state = EMISSION_RUN;
       handler_ref (handler);
       do
        {
@@ -1999,21 +2815,22 @@ signal_emit_R (SignalNode   *node,
              handler_list = handler;
              break;
            }
-         else if (!handler->block_count && (!handler->detail || handler->detail == detail))
+         else if (!handler->block_count && (!handler->detail || handler->detail == detail) &&
+                  handler->sequential_number < max_sequential_handler_number)
            {
-             G_UNLOCK (g_signal_mutex);
+             SIGNAL_UNLOCK ();
              g_closure_invoke (handler->closure,
                                return_accu,
                                node->n_params + 1,
                                instance_and_params,
-                               &ihint);
-             if (!accumulate (&ihint, emission_return, &accu, accumulator) &&
-                 emission_state == EMISSION_RUN)
-               emission_state = EMISSION_STOP;
-             G_LOCK (g_signal_mutex);
+                               &emission.ihint);
+             if (!accumulate (&emission.ihint, emission_return, &accu, accumulator) &&
+                 emission.state == EMISSION_RUN)
+               emission.state = EMISSION_STOP;
+             SIGNAL_LOCK ();
              return_value_altered = TRUE;
              
-             tmp = emission_state == EMISSION_RUN ? handler->next : NULL;
+             tmp = emission.state == EMISSION_RUN ? handler->next : NULL;
            }
          else
            tmp = handler->next;
@@ -2026,33 +2843,35 @@ signal_emit_R (SignalNode   *node,
        }
       while (handler);
       
-      if (emission_state == EMISSION_STOP)
+      if (emission.state == EMISSION_STOP)
        goto EMIT_CLEANUP;
-      else if (emission_state == EMISSION_RESTART)
+      else if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
-  ihint.run_type = G_SIGNAL_RUN_LAST;
+  emission.ihint.run_type = G_SIGNAL_RUN_LAST;
   
   if ((node->flags & G_SIGNAL_RUN_LAST) && class_closure)
     {
-      emission_state = EMISSION_RUN;
+      emission.state = EMISSION_RUN;
       
-      G_UNLOCK (g_signal_mutex);
+      emission.chain_type = G_TYPE_FROM_INSTANCE (instance);
+      SIGNAL_UNLOCK ();
       g_closure_invoke (class_closure,
                        return_accu,
                        node->n_params + 1,
                        instance_and_params,
-                       &ihint);
-      if (!accumulate (&ihint, emission_return, &accu, accumulator) &&
-         emission_state == EMISSION_RUN)
-       emission_state = EMISSION_STOP;
-      G_LOCK (g_signal_mutex);
+                       &emission.ihint);
+      if (!accumulate (&emission.ihint, emission_return, &accu, accumulator) &&
+         emission.state == EMISSION_RUN)
+       emission.state = EMISSION_STOP;
+      SIGNAL_LOCK ();
+      emission.chain_type = G_TYPE_NONE;
       return_value_altered = TRUE;
       
-      if (emission_state == EMISSION_STOP)
+      if (emission.state == EMISSION_STOP)
        goto EMIT_CLEANUP;
-      else if (emission_state == EMISSION_RESTART)
+      else if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
@@ -2060,27 +2879,28 @@ signal_emit_R (SignalNode   *node,
     {
       Handler *handler = handler_list;
       
-      emission_state = EMISSION_RUN;
+      emission.state = EMISSION_RUN;
       handler_ref (handler);
       do
        {
          Handler *tmp;
          
-         if (handler->after && !handler->block_count && (!handler->detail || handler->detail == detail))
+         if (handler->after && !handler->block_count && (!handler->detail || handler->detail == detail) &&
+             handler->sequential_number < max_sequential_handler_number)
            {
-             G_UNLOCK (g_signal_mutex);
+             SIGNAL_UNLOCK ();
              g_closure_invoke (handler->closure,
                                return_accu,
                                node->n_params + 1,
                                instance_and_params,
-                               &ihint);
-             if (!accumulate (&ihint, emission_return, &accu, accumulator) &&
-                 emission_state == EMISSION_RUN)
-               emission_state = EMISSION_STOP;
-             G_LOCK (g_signal_mutex);
+                               &emission.ihint);
+             if (!accumulate (&emission.ihint, emission_return, &accu, accumulator) &&
+                 emission.state == EMISSION_RUN)
+               emission.state = EMISSION_STOP;
+             SIGNAL_LOCK ();
              return_value_altered = TRUE;
              
-             tmp = emission_state == EMISSION_RUN ? handler->next : NULL;
+             tmp = emission.state == EMISSION_RUN ? handler->next : NULL;
            }
          else
            tmp = handler->next;
@@ -2092,23 +2912,24 @@ signal_emit_R (SignalNode   *node,
        }
       while (handler);
       
-      if (emission_state == EMISSION_STOP)
+      if (emission.state == EMISSION_STOP)
        goto EMIT_CLEANUP;
-      else if (emission_state == EMISSION_RESTART)
+      else if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
  EMIT_CLEANUP:
   
-  ihint.run_type = G_SIGNAL_RUN_CLEANUP;
+  emission.ihint.run_type = G_SIGNAL_RUN_CLEANUP;
   
   if ((node->flags & G_SIGNAL_RUN_CLEANUP) && class_closure)
     {
       gboolean need_unset = FALSE;
       
-      emission_state = EMISSION_STOP;
+      emission.state = EMISSION_STOP;
       
-      G_UNLOCK (g_signal_mutex);
+      emission.chain_type = G_TYPE_FROM_INSTANCE (instance);
+      SIGNAL_UNLOCK ();
       if (node->return_type != G_TYPE_NONE && !accumulator)
        {
          g_value_init (&accu, node->return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE);
@@ -2118,25 +2939,38 @@ signal_emit_R (SignalNode   *node,
                        node->return_type != G_TYPE_NONE ? &accu : NULL,
                        node->n_params + 1,
                        instance_and_params,
-                       &ihint);
+                       &emission.ihint);
       if (need_unset)
        g_value_unset (&accu);
-      G_LOCK (g_signal_mutex);
+      SIGNAL_LOCK ();
+      emission.chain_type = G_TYPE_NONE;
       
-      if (emission_state == EMISSION_RESTART)
+      if (emission.state == EMISSION_RESTART)
        goto EMIT_RESTART;
     }
   
   if (handler_list)
     handler_unref_R (signal_id, instance, handler_list);
   
-  emission_pop ((node->flags & G_SIGNAL_NO_RECURSE) ? &g_restart_emissions : &g_recursive_emissions, &emission_state);
+  emission_pop ((node->flags & G_SIGNAL_NO_RECURSE) ? &g_restart_emissions : &g_recursive_emissions, &emission);
+  SIGNAL_UNLOCK ();
   if (accumulator)
     g_value_unset (&accu);
   
   return return_value_altered;
 }
 
+static const gchar*
+type_debug_name (GType type)
+{
+  if (type)
+    {
+      const char *name = g_type_name (type & ~G_SIGNAL_TYPE_STATIC_SCOPE);
+      return name ? name : "<unknown>";
+    }
+  else
+    return "<invalid>";
+}
 
 /* --- compile standard marshallers --- */
 #include       "gobject.h"