Fix some issues with PLT entries.
[platform/upstream/glib.git] / gobject / gsignal.c
index c78563d..c65565a 100644 (file)
  * MT safe
  */
 
+#include <config.h>
+
 #include        "gsignal.h"
+
 #include        "gbsearcharray.h"
 #include        "gvaluecollector.h"
 #include       "gvaluetypes.h"
 #include       "gboxed.h"
+#include       "gobject.h"
+#include       "genums.h"
+
+#include       "gobjectalias.h"
+
 #include       <string.h> 
+#include       <signal.h>
 
 
 /* pre allocation configurations
  */
 #define        MAX_STACK_VALUES        (16)
-#define HANDLER_PRE_ALLOC       (48)
-#define EMISSION_PRE_ALLOC      (16)
 
-#define REPORT_BUG      "please report occourance circumstances to gtk-devel-list@gnome.org"
+#define REPORT_BUG      "please report occurrence 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 */
 
 
-/* --- generic allocation --- */
-/* we special case allocations generically by replacing
- * these functions with more speed/memory aware variants
- */
-#ifndef        DISABLE_MEM_POOLS
-static inline gpointer
-g_generic_node_alloc (GTrashStack **trash_stack_p,
-                      guint         sizeof_node,
-                      guint         nodes_pre_alloc)
-{
-  gpointer node = g_trash_stack_pop (trash_stack_p);
-  
-  if (!node)
-    {
-      guint8 *block;
-      
-      nodes_pre_alloc = MAX (nodes_pre_alloc, 1);
-      block = g_malloc (sizeof_node * nodes_pre_alloc);
-      while (--nodes_pre_alloc)
-        {
-          g_trash_stack_push (trash_stack_p, block);
-          block += sizeof_node;
-        }
-      node = block;
-    }
-  
-  return node;
-}
-#define        g_generic_node_free(trash_stack_p, node) g_trash_stack_push (trash_stack_p, node)
-#else  /* !DISABLE_MEM_POOLS */
-#define        g_generic_node_alloc(t,sizeof_node,p)    g_malloc (sizeof_node)
-#define        g_generic_node_free(t,node)              g_free (node)
-#endif /* !DISABLE_MEM_POOLS */
-
-
 /* --- typedefs --- */
 typedef struct _SignalNode   SignalNode;
 typedef struct _SignalKey    SignalKey;
@@ -110,7 +82,7 @@ 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,
@@ -129,24 +101,26 @@ 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 gint                    class_closures_cmp      (gconstpointer    node1,
+                                                        gconstpointer    node2);
 static gint                    signal_key_cmp          (gconstpointer    node1,
                                                         gconstpointer    node2);
-static       gboolean          signal_emit_R           (SignalNode      *node,
+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 --- */
@@ -167,19 +141,22 @@ struct _SignalNode
   /* permanent portion */
   guint              signal_id;
   GType              itype;
-  gchar             *name;
+  const gchar       *name;
   guint              destroyed : 1;
   
   /* reinitializable portion */
+  guint                     test_class_offset : 12;
   guint              flags : 8;
   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;
 };
+#define        MAX_TEST_CLASS_OFFSET   (4096)  /* 2^12, 12 bits for test_class_offset */
+#define        TEST_CLASS_MAGIC        (1)     /* indicates NULL class closure, candidate for NOP optimization */
 
 struct _SignalKey
 {
@@ -190,28 +167,30 @@ 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
 {
   guint    signal_id;
   Handler *handlers;
+  Handler *tail_before;  /* normal signal handlers are appended here  */
+  Handler *tail_after;   /* CONNECT_AFTER handlers are appended here  */
 };
+
 struct _Handler
 {
-  guint         id;
+  gulong        sequential_number;
   Handler      *next;
   Handler      *prev;
   GQuark       detail;
-  guint         ref_count : 16;
-#define HANDLER_MAX_REF_COUNT   (1 << 16)
-  guint         block_count : 12;
-#define HANDLER_MAX_BLOCK_COUNT (1 << 12)
+  guint         ref_count;
+  guint         block_count : 16;
+#define HANDLER_MAX_BLOCK_COUNT (1 << 16)
   guint         after : 1;
   GClosure     *closure;
 };
@@ -219,23 +198,40 @@ struct _HandlerMatch
 {
   Handler      *handler;
   HandlerMatch *next;
-  union {
-    guint       signal_id;
-    gpointer   dummy;
-  } d;
+  guint         signal_id;
 };
 
+typedef struct
+{
+  GType     instance_type; /* 0 for default closure */
+  GClosure *closure;
+} ClassClosure;
+
 
 /* --- variables --- */
-static GBSearchArray  g_signal_key_bsa = G_STATIC_BSEARCH_ARRAY_INIT (sizeof (SignalKey),
-                                                                     signal_key_cmp,
-                                                                     G_BSEARCH_ARRAY_ALIGN_POWER2);
+static GBSearchArray *g_signal_key_bsa = NULL;
+static const GBSearchConfig g_signal_key_bconfig = {
+  sizeof (SignalKey),
+  signal_key_cmp,
+  G_BSEARCH_ARRAY_ALIGN_POWER2,
+};
+static GBSearchConfig g_signal_hlbsa_bconfig = {
+  sizeof (HandlerList),
+  handler_lists_cmp,
+  0,
+};
+static GBSearchConfig g_class_closure_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_handler_ts = NULL;
-static GTrashStack   *g_emission_ts = NULL;
+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 --- */
@@ -263,13 +259,13 @@ signal_id_lookup (GQuark quark,
 
   key.quark = quark;
 
-  /* try looking up signals for this type and its anchestors */
+  /* try looking up signals for this type and its ancestors */
   do
     {
       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;
@@ -285,7 +281,7 @@ 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)
        {
@@ -299,6 +295,15 @@ 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)
 {
@@ -314,15 +319,25 @@ 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;
+  key.tail_before = NULL;
+  key.tail_after  = NULL;
   if (!hlbsa)
     {
-      hlbsa = g_bsearch_array_new (sizeof (HandlerList), handler_lists_cmp, G_BSEARCH_ARRAY_DEFER_SHRINK);
+      hlbsa = g_bsearch_array_create (&g_signal_hlbsa_bconfig);
+      hlbsa = g_bsearch_array_insert (hlbsa, &g_signal_hlbsa_bconfig, &key);
       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);
+      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*
@@ -334,12 +349,12 @@ 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);
@@ -350,11 +365,11 @@ 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;
@@ -374,15 +389,10 @@ handler_match_prepend (HandlerMatch *list,
 {
   HandlerMatch *node;
   
-  /* yeah, we could use our own memchunk here, introducing yet more
-   * rarely used cached nodes and extra allocation overhead.
-   * instead, we use GList* nodes, since they are exactly the size
-   * we need and are already cached. g_signal_init() asserts this.
-   */
-  node = (HandlerMatch*) g_list_alloc ();
+  node = g_slice_new (HandlerMatch);
   node->handler = handler;
   node->next = list;
-  node->d.signal_id = signal_id;
+  node->signal_id = signal_id;
   handler_ref (handler);
   
   return node;
@@ -393,8 +403,8 @@ handler_match_free1_R (HandlerMatch *node,
 {
   HandlerMatch *next = node->next;
   
-  handler_unref_R (node->d.signal_id, instance, node->handler);
-  g_list_free_1 ((GList*) node);
+  handler_unref_R (node->signal_id, instance, node->handler);
+  g_slice_free (HandlerMatch, node);
   
   return next;
 }
@@ -426,7 +436,7 @@ 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) &&
@@ -451,7 +461,7 @@ 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;
               
@@ -463,7 +473,7 @@ 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) &&
@@ -486,16 +496,13 @@ 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);
+  Handler *handler = g_slice_new (Handler);
 #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;
@@ -512,12 +519,7 @@ handler_ref (Handler *handler)
 {
   g_return_if_fail (handler->ref_count > 0);
   
-#ifndef G_DISABLE_CHECKS
-  if (handler->ref_count >= HANDLER_MAX_REF_COUNT - 1)
-    g_error (G_STRLOC ": handler ref_count overflow, %s", REPORT_BUG);
-#endif
-  
-  handler->ref_count += 1;
+  g_atomic_int_inc (&handler->ref_count);
 }
 
 static inline void
@@ -525,25 +527,57 @@ handler_unref_R (guint    signal_id,
                 gpointer instance,
                 Handler *handler)
 {
+  gboolean is_zero;
+
   g_return_if_fail (handler->ref_count > 0);
   
-  handler->ref_count -= 1;
-  if (!handler->ref_count)
+  is_zero = g_atomic_int_dec_and_test (&handler->ref_count);
+
+  if (G_UNLIKELY (is_zero))
     {
+      HandlerList *hlist = NULL;
+
       if (handler->next)
         handler->next->prev = handler->prev;
-      if (handler->prev)       /* watch out for g_signal_handlers_destroy()! */
+      if (handler->prev)    /* watch out for g_signal_handlers_destroy()! */
         handler->prev->next = handler->next;
       else
         {
-          HandlerList *hlist = handler_list_lookup (signal_id, instance);
-          
+          hlist = handler_list_lookup (signal_id, instance);
           hlist->handlers = handler->next;
         }
-      G_UNLOCK (g_signal_mutex);
+
+      if (instance)
+        {
+          /*  check if we are removing the handler pointed to by tail_before  */
+          if (!handler->after && (!handler->next || handler->next->after))
+            {
+              if (!hlist)
+                hlist = handler_list_lookup (signal_id, instance);
+              if (hlist)
+                {
+                  g_assert (hlist->tail_before == handler); /* paranoid */
+                  hlist->tail_before = handler->prev;
+                }
+            }
+
+          /*  check if we are removing the handler pointed to by tail_after  */
+          if (!handler->next)
+            {
+              if (!hlist)
+                hlist = handler_list_lookup (signal_id, instance);
+              if (hlist)
+                {
+                  g_assert (hlist->tail_after == handler); /* paranoid */
+                  hlist->tail_after = handler->prev;
+                }
+            }
+        }
+
+      SIGNAL_UNLOCK ();
       g_closure_unref (handler->closure);
-      G_LOCK (g_signal_mutex);
-      g_generic_node_free (&g_handler_ts, handler);
+      SIGNAL_LOCK ();
+      g_slice_free (Handler, handler);
     }
 }
 
@@ -558,62 +592,64 @@ handler_insert (guint    signal_id,
   
   hlist = handler_list_ensure (signal_id, instance);
   if (!hlist->handlers)
-    hlist->handlers = handler;
-  else if (hlist->handlers->after && !handler->after)
     {
-      handler->next = hlist->handlers;
-      hlist->handlers->prev = handler;
       hlist->handlers = handler;
+      if (!handler->after)
+        hlist->tail_before = handler;
+    }
+  else if (handler->after)
+    {
+      handler->prev = hlist->tail_after;
+      hlist->tail_after->next = handler;
     }
   else
     {
-      Handler *tmp = hlist->handlers;
-      
-      if (handler->after)
-        while (tmp->next)
-          tmp = tmp->next;
-      else
-        while (tmp->next && !tmp->next->after)
-          tmp = tmp->next;
-      if (tmp->next)
-        tmp->next->prev = handler;
-      handler->next = tmp->next;
-      handler->prev = tmp;
-      tmp->next = handler;
+      if (hlist->tail_before)
+        {
+          handler->next = hlist->tail_before->next;
+          if (handler->next)
+            handler->next->prev = handler;
+          handler->prev = hlist->tail_before;
+          hlist->tail_before->next = handler;
+        }
+      else /* insert !after handler into a list of only after handlers */
+        {
+          handler->next = hlist->handlers;
+          if (handler->next)
+            handler->next->prev = handler;
+          hlist->handlers = handler;
+        }
+      hlist->tail_before = handler;
     }
+
+  if (!handler->next)
+    hlist->tail_after = handler;
 }
 
 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*
@@ -626,12 +662,37 @@ 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)
@@ -645,23 +706,21 @@ signal_key_cmp (gconstpointer node1,
 }
 
 void
-g_signal_init (void) /* sync with gtype.c */
+g_signal_init (void)
 {
-  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 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_create (&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
@@ -669,7 +728,7 @@ _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];
@@ -679,12 +738,12 @@ _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 ();
 }
 
 void
@@ -697,12 +756,12 @@ 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))
@@ -712,11 +771,11 @@ 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'",
@@ -724,7 +783,7 @@ 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
@@ -736,20 +795,20 @@ 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
+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;
@@ -757,18 +816,24 @@ 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))
+  if (!node || node->destroyed)
     {
       g_warning ("%s: invalid signal id `%u'", G_STRLOC, signal_id);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
+      return 0;
+    }
+  if (node->flags & G_SIGNAL_NO_HOOKS) 
+    {
+      g_warning ("%s: signal id `%u' does not support emission hooks (G_SIGNAL_NO_HOOKS flag set)", G_STRLOC, signal_id);
+      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)
@@ -779,34 +844,34 @@ 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;
 }
 
 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
@@ -867,9 +932,9 @@ 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 ||
@@ -884,59 +949,77 @@ g_signal_parse_name (const gchar *detailed_signal,
   return TRUE;
 }
 
+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 ();
+}
+
 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;
 }
 
 guint*
@@ -951,10 +1034,9 @@ 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_get_nth (g_signal_key_bsa, &g_signal_key_bconfig, 0);
+  n_nodes = g_bsearch_array_get_n_nodes (g_signal_key_bsa);
   result = g_array_new (FALSE, FALSE, sizeof (guint));
   
   for (i = 0; i < n_nodes; i++)
@@ -968,59 +1050,75 @@ g_signal_list_ids (GType  itype,
        if (!strchr (name, '_'))
          g_array_append_val (result, keys[i].signal_id);
       }
-  
   *n_ids = result->len;
-  
-  G_UNLOCK (g_signal_mutex);
+  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));
+    }
   
   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_CONST_RETURN gchar*
+g_signal_name (guint signal_id)
 {
-  GType *param_types;
-  guint i;
-  guint signal_id;
+  SignalNode *node;
+  const gchar *name;
+  
+  SIGNAL_LOCK ();
+  node = LOOKUP_SIGNAL_NODE (signal_id);
+  name = node ? node->name : NULL;
+  SIGNAL_UNLOCK ();
+  
+  return (char*) name;
+}
 
-  if (n_params > 0)
+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 ();
 }
 
 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;
@@ -1035,10 +1133,83 @@ g_signal_newc (const gchar       *signal_name,
                                    return_type, n_params, args);
 
   va_end (args);
+
+  /* optimize NOP emissions with NULL class handlers */
+  if (signal_id && G_TYPE_IS_INSTANTIATABLE (itype) && return_type == G_TYPE_NONE &&
+      class_offset && class_offset < MAX_TEST_CLASS_OFFSET)
+    {
+      SignalNode *node;
+
+      SIGNAL_LOCK ();
+      node = LOOKUP_SIGNAL_NODE (signal_id);
+      node->test_class_offset = class_offset;
+      SIGNAL_UNLOCK ();
+    }
  
   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 && g_bsearch_array_get_n_nodes (node->class_closure_bsa) == 1)
+    cc = g_bsearch_array_get_nth (node->class_closure_bsa, &g_class_closure_bconfig, 0);
+  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;
+
+  /* can't optimize NOP emissions with overridden class closures */
+  node->test_class_offset = 0;
+
+  if (!node->class_closure_bsa)
+    node->class_closure_bsa = g_bsearch_array_create (&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);
+  g_closure_sink (closure);
+  if (node->c_marshaller && closure && G_CLOSURE_NEEDS_MARSHAL (closure))
+    g_closure_set_marshal (closure, node->c_marshaller);
+}
+
 guint
 g_signal_newv (const gchar       *signal_name,
                GType              itype,
@@ -1066,9 +1237,9 @@ g_signal_newv (const gchar       *signal_name,
     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);
@@ -1076,47 +1247,46 @@ 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);
-      G_UNLOCK (g_signal_mutex);
+      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",
-                g_type_name (itype), name,
-                g_type_name (return_type & ~G_SIGNAL_TYPE_STATIC_SCOPE));
+                type_debug_name (itype), name, type_debug_name (return_type));
       g_free (name);
-      G_UNLOCK (g_signal_mutex);
+      SIGNAL_UNLOCK ();
       return 0;
     }
   
@@ -1135,21 +1305,21 @@ 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_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);
+      g_strdelimit (name, "_", '-');
+      node->name = g_intern_string (name);
+      key.quark = g_quark_from_string (name);
+      g_signal_key_bsa = g_bsearch_array_insert (g_signal_key_bsa, &g_signal_key_bconfig, &key);
     }
   node->destroyed = FALSE;
-  
+  node->test_class_offset = 0;
+
   /* setup reinitializable portion */
   node->flags = signal_flags & G_SIGNAL_FLAGS_MASK;
   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);
@@ -1160,9 +1330,51 @@ 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);
+  else if (G_TYPE_IS_INSTANTIATABLE (itype) && return_type == G_TYPE_NONE)
+    {
+      /* optimize NOP emissions */
+      node->test_class_offset = TEST_CLASS_MAGIC;
+    }
+  SIGNAL_UNLOCK ();
+
+  g_free (name);
+
+  return 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;
 }
 
@@ -1170,14 +1382,15 @@ 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->test_class_offset = 0;
   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;
@@ -1189,7 +1402,7 @@ 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);
   }
@@ -1197,19 +1410,129 @@ 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_free (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
+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 ();
+}
+
+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 ();
+}
+
+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;
+}
+
+gulong
 g_signal_connect_closure_by_id (gpointer  instance,
                                guint     signal_id,
                                GQuark    detail,
@@ -1217,13 +1540,13 @@ 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)
     {
@@ -1235,7 +1558,7 @@ 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);
@@ -1246,18 +1569,19 @@ 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
+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;
 
@@ -1265,7 +1589,7 @@ 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)
@@ -1280,7 +1604,7 @@ 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);
@@ -1291,29 +1615,33 @@ 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
+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)
@@ -1328,7 +1656,7 @@ 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);
@@ -1339,21 +1667,21 @@ 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;
 }
 
 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)
     {
@@ -1361,40 +1689,39 @@ 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 ();
 }
 
 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 ();
 }
 
 void
 g_signal_handler_disconnect (gpointer instance,
-                             guint    handler_id)
+                             gulong   handler_id)
 {
   Handler *handler;
   guint signal_id;
@@ -1402,17 +1729,34 @@ 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 ();
+}
+
+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);
+
+  SIGNAL_LOCK ();
+  handler = handler_lookup (instance, handler_id, NULL);
+  connected = handler != NULL;
+  SIGNAL_UNLOCK ();
+
+  return connected;
 }
 
 void
@@ -1422,7 +1766,7 @@ 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)
     {
@@ -1433,7 +1777,7 @@ 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)
@@ -1445,19 +1789,19 @@ 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_bsearch_array_destroy (hlbsa);
+      g_bsearch_array_free (hlbsa, &g_signal_hlbsa_bconfig);
     }
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
 }
 
-guint
+gulong
 g_signal_handler_find (gpointer         instance,
                        GSignalMatchType mask,
                        guint            signal_id,
@@ -1466,7 +1810,7 @@ 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 +1819,17 @@ 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 +1841,7 @@ 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;
@@ -1506,9 +1850,12 @@ 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);
     }
   
@@ -1526,16 +1873,16 @@ g_signal_handlers_block_matched (gpointer         instance,
 {
   guint n_handlers = 0;
   
-  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), FALSE);
-  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, FALSE);
+  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
+  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, 0);
   
   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;
@@ -1552,16 +1899,16 @@ g_signal_handlers_unblock_matched (gpointer         instance,
 {
   guint n_handlers = 0;
   
-  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), FALSE);
-  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, FALSE);
+  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
+  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, 0);
   
   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;
@@ -1578,16 +1925,16 @@ g_signal_handlers_disconnect_matched (gpointer         instance,
 {
   guint n_handlers = 0;
   
-  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), FALSE);
-  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, FALSE);
+  g_return_val_if_fail (G_TYPE_CHECK_INSTANCE (instance), 0);
+  g_return_val_if_fail ((mask & ~G_SIGNAL_MATCH_MASK) == 0, 0);
   
   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;
@@ -1605,7 +1952,7 @@ 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 +1960,7 @@ 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;
        }
     }
@@ -1627,42 +1974,90 @@ g_signal_has_handler_pending (gpointer instance,
     }
   else
     has_pending = FALSE;
-  G_UNLOCK (g_signal_mutex);
+  SIGNAL_UNLOCK ();
   
   return has_pending;
 }
 
+static inline gboolean
+signal_check_skip_emission (SignalNode *node,
+                           gpointer    instance,
+                           GQuark      detail)
+{
+  HandlerList *hlist;
+
+  /* are we able to check for NULL class handlers? */
+  if (!node->test_class_offset)
+    return FALSE;
+
+  /* are there emission hooks pending? */
+  if (node->emission_hooks && node->emission_hooks->hooks)
+    return FALSE;
+
+  /* is there a non-NULL class handler? */
+  if (node->test_class_offset != TEST_CLASS_MAGIC)
+    {
+      GTypeClass *class = G_TYPE_INSTANCE_GET_CLASS (instance, G_TYPE_FROM_INSTANCE (instance), GTypeClass);
+
+      if (G_STRUCT_MEMBER (gpointer, class, node->test_class_offset))
+       return FALSE;
+    }
+
+  /* are signals being debugged? */
+#ifdef  G_ENABLE_DEBUG
+  IF_DEBUG (SIGNALS, g_trace_instance_signals || g_trap_instance_signals)
+    return FALSE;
+#endif /* G_ENABLE_DEBUG */
+
+  /* is this a no-recurse signal already in emission? */
+  if (node->flags & G_SIGNAL_NO_RECURSE &&
+      emission_find (g_restart_emissions, node->signal_id, detail, instance))
+    return FALSE;
+
+  /* do we have pending handlers? */
+  hlist = handler_list_lookup (node->signal_id, instance);
+  if (hlist && hlist->handlers)
+    return FALSE;
+
+  /* none of the above, no emission required */
+  return TRUE;
+}
+
 void
 g_signal_emitv (const GValue *instance_and_params,
                guint         signal_id,
                GQuark        detail,
                GValue       *return_value)
 {
-  const GValue *param_values;
   gpointer instance;
   SignalNode *node;
+#ifdef G_ENABLE_DEBUG
+  const GValue *param_values;
   guint i;
+#endif
   
   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));
   g_return_if_fail (signal_id > 0);
 
+#ifdef G_ENABLE_DEBUG
   param_values = instance_and_params + 1;
-  
-  G_LOCK (g_signal_mutex);
+#endif
+
+  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 +2065,11 @@ 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 +2078,19 @@ 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;
        }
     }
@@ -1703,8 +2098,17 @@ 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);
+  /* optimize NOP emissions */
+  if (signal_check_skip_emission (node, instance, detail))
+    {
+      /* nothing to do to emit this signal */
+      SIGNAL_UNLOCK ();
+      /* g_printerr ("omitting emission of \"%s\"\n", node->name); */
+      return;
+    }
+
+  SIGNAL_UNLOCK ();
+  signal_emit_unlocked_R (node, detail, instance, return_value, instance_and_params);
 }
 
 void
@@ -1714,30 +2118,42 @@ 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 */
 
+  /* optimize NOP emissions */
+  if (signal_check_skip_emission (node, instance, detail))
+    {
+      /* nothing to do to emit this signal */
+      SIGNAL_UNLOCK ();
+      /* g_printerr ("omitting emission of \"%s\"\n", node->name); */
+      return;
+    }
+
+  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 +2165,15 @@ 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)
        {
@@ -1767,45 +2186,49 @@ 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
+          * in a sane state if an error condition occured
           */
        }
     }
-  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);
 }
 
 void
@@ -1832,9 +2255,9 @@ 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)
     {
@@ -1866,20 +2289,20 @@ 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
@@ -1894,60 +2317,71 @@ 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 +2390,7 @@ 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 +2398,13 @@ 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 +2413,7 @@ 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 +2421,7 @@ signal_emit_R (SignalNode   *node,
     {
       Handler *handler = handler_list;
       
-      emission_state = EMISSION_RUN;
+      emission.state = EMISSION_RUN;
       handler_ref (handler);
       do
        {
@@ -1999,21 +2433,22 @@ 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 +2461,35 @@ 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 +2497,28 @@ 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 +2530,24 @@ 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);
@@ -2118,27 +2557,57 @@ 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>";
+}
+
+gboolean
+g_signal_accumulator_true_handled (GSignalInvocationHint *ihint,
+                                  GValue                *return_accu,
+                                  const GValue          *handler_return,
+                                  gpointer               dummy)
+{
+  gboolean continue_emission;
+  gboolean signal_handled;
+  
+  signal_handled = g_value_get_boolean (handler_return);
+  g_value_set_boolean (return_accu, signal_handled);
+  continue_emission = !signal_handled;
+  
+  return continue_emission;
+}
 
 /* --- compile standard marshallers --- */
-#include       "gobject.h"
-#include       "genums.h"
 #include        "gmarshal.c"
+
+#define __G_SIGNAL_C__
+#include "gobjectaliasdef.c"