/* GObject - GLib Type, Object, Parameter and Signal Library

 * Copyright (C) 2000-2001 Red Hat, Inc.

 * Portions copyright (c) 2006-2009 Nokia Corporation.  All rights reserved.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General

 * Public License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 *

 * this code is based on the original GtkSignal implementation

 * for the Gtk+ library by Peter Mattis <petm@xcf.berkeley.edu>

 */

/*

 * MT safe

 */

#include "config.h"

#include <string.h>

#include <signal.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"

#ifdef __SYMBIAN32__

#include <glib_global.h>

#include "gobject_wsd.h"

#endif /* __SYMBIAN32__ */

/**

 * SECTION:signals

 * @short_description: A means for customization of object behaviour

 *     and a general purpose notification mechanism

 * @title: Signals

 *

 * The basic concept of the signal system is that of the

 * <emphasis>emission</emphasis> of a signal. Signals are introduced

 * per-type and are identified through strings.  Signals introduced

 * for a parent type are available in derived types as well, so

 * basically they are a per-type facility that is inherited.  A signal

 * emission mainly involves invocation of a certain set of callbacks

 * in precisely defined manner. There are two main categories of such

 * callbacks, per-object 

 * <footnote><para>Although signals can deal with any kind of instantiatable 

 * type, i'm referring to those types as "object types" in the following, 

 * simply because that is the context most users will encounter signals in.

 * </para></footnote>

 * ones and user provided ones.

 * The per-object callbacks are most often referred to as "object method

 * handler" or "default (signal) handler", while user provided callbacks are

 * usually just called "signal handler".

 * The object method handler is provided at signal creation time (this most

 * frequently happens at the end of an object class' creation), while user

 * provided handlers are frequently connected and disconnected to/from a certain

 * signal on certain object instances.

 *

 * A signal emission consists of five stages, unless prematurely stopped:

 * <variablelist>

 * <varlistentry><term></term><listitem><para>

 * 	1 - Invocation of the object method handler for %G_SIGNAL_RUN_FIRST signals

 * </para></listitem></varlistentry>

 * <varlistentry><term></term><listitem><para>

 * 	2 - Invocation of normal user-provided signal handlers (<emphasis>after</emphasis> flag %FALSE)

 * </para></listitem></varlistentry>

 * <varlistentry><term></term><listitem><para>

 * 	3 - Invocation of the object method handler for %G_SIGNAL_RUN_LAST signals

 * </para></listitem></varlistentry>

 * <varlistentry><term></term><listitem><para>

 * 	4 - Invocation of user provided signal handlers, connected with an <emphasis>after</emphasis> flag of %TRUE

 * </para></listitem></varlistentry>

 * <varlistentry><term></term><listitem><para>

 * 	5 - Invocation of the object method handler for %G_SIGNAL_RUN_CLEANUP signals

 * </para></listitem></varlistentry>

 * </variablelist>

 * The user-provided signal handlers are called in the order they were

 * connected in.

 * All handlers may prematurely stop a signal emission, and any number of

 * handlers may be connected, disconnected, blocked or unblocked during

 * a signal emission.

 * There are certain criteria for skipping user handlers in stages 2 and 4

 * of a signal emission.

 * First, user handlers may be <emphasis>blocked</emphasis>, blocked handlers are omitted

 * during callback invocation, to return from the "blocked" state, a

 * handler has to get unblocked exactly the same amount of times

 * it has been blocked before.

 * Second, upon emission of a %G_SIGNAL_DETAILED signal, an additional

 * "detail" argument passed in to g_signal_emit() has to match the detail

 * argument of the signal handler currently subject to invocation.

 * Specification of no detail argument for signal handlers (omission of the

 * detail part of the signal specification upon connection) serves as a

 * wildcard and matches any detail argument passed in to emission.

 */

#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)

#if EMULATOR

PLS(g_trace_instance_signals,gsignal,volatile gpointer )

PLS(g_trap_instance_signals,gsignal,volatile gpointer )

#define g_trace_instance_signals (*FUNCTION_NAME(g_trace_instance_signals,gsignal)())

#define g_trap_instance_signals (*FUNCTION_NAME(g_trap_instance_signals,gsignal)())

#else

static volatile gpointer g_trace_instance_signals = NULL;

static volatile gpointer g_trap_instance_signals = NULL;

#endif /* EMULATOR */

#endif	/* G_ENABLE_DEBUG */

/* --- typedefs --- */

typedef struct _SignalNode   SignalNode;

typedef struct _SignalKey    SignalKey;

typedef struct _Emission     Emission;

typedef struct _Handler      Handler;

typedef struct _HandlerList  HandlerList;

typedef struct _HandlerMatch HandlerMatch;

typedef enum

{

  EMISSION_STOP,

  EMISSION_RUN,

  EMISSION_HOOK,

  EMISSION_RESTART

} EmissionState;

/* --- prototypes --- */

static inline guint		signal_id_lookup	(GQuark		  quark,

							 GType		  itype);

static	      void		signal_destroy_R	(SignalNode	 *signal_node);

static inline HandlerList*	handler_list_ensure	(guint		  signal_id,

							 gpointer	  instance);

static inline HandlerList*	handler_list_lookup	(guint		  signal_id,

							 gpointer	  instance);

static inline Handler*		handler_new		(gboolean	  after);

static	      void		handler_insert		(guint		  signal_id,

							 gpointer	  instance,

							 Handler	 *handler);

static	      Handler*		handler_lookup		(gpointer	  instance,

							 gulong		  handler_id,

							 guint		 *signal_id_p);

static inline HandlerMatch*	handler_match_prepend	(HandlerMatch	 *list,

							 Handler	 *handler,

							 guint		  signal_id);

static inline HandlerMatch*	handler_match_free1_R	(HandlerMatch	 *node,

							 gpointer	  instance);

static	      HandlerMatch*	handlers_find		(gpointer	  instance,

							 GSignalMatchType mask,

							 guint		  signal_id,

							 GQuark		  detail,

							 GClosure	 *closure,

							 gpointer	  func,

							 gpointer	  data,

							 gboolean	  one_and_only);

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,

							 Emission	 *emission);

static inline void		emission_pop		(Emission	**emission_list_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_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 --- */

typedef struct

{

  GSignalAccumulator func;

  gpointer           data;

} SignalAccumulator;

typedef struct

{

  GHook hook;

  GQuark detail;

} SignalHook;

#define	SIGNAL_HOOK(hook)	((SignalHook*) (hook))

struct _SignalNode

{

  /* permanent portion */

  guint              signal_id;

  GType              itype;

  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 */

  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

{

  GType  itype;

  GQuark quark;

  guint  signal_id;

};

struct _Emission

{

  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

{

  gulong        sequential_number;

  Handler      *next;

  Handler      *prev;

  GQuark	detail;

  guint         ref_count;

  guint         block_count : 16;

#define HANDLER_MAX_BLOCK_COUNT (1 << 16)

  guint         after : 1;

  GClosure     *closure;

};

struct _HandlerMatch

{

  Handler      *handler;

  HandlerMatch *next;

  guint         signal_id;

};

typedef struct

{

  GType     instance_type; /* 0 for default closure */

  GClosure *closure;

} ClassClosure;

/* --- variables --- */

#if EMULATOR

PLS(g_signal_key_bsa,gsignal,GBSearchArray *)

PLS(g_signal_hlbsa_bconfig,gsignal,GBSearchConfig)

PLS(g_class_closure_bconfig,gsignal,GBSearchConfig)

PLS(g_handler_list_bsa_ht,gsignal,GHashTable    *)

PLS(g_recursive_emissions,gsignal,Emission *)

PLS(g_restart_emissions ,gsignal,Emission *)

PLS(g_handler_sequential_number ,gsignal,gulong)

PLS_MACRO(g_signal_mutex,gsignal,GStaticMutex)

PLS(g_n_signal_nodes,gsignal,guint)

PLS(g_signal_nodes ,gsignal,SignalNode   **)

#define g_signal_key_bsa (*FUNCTION_NAME(g_signal_key_bsa,gsignal)())

#define g_signal_hlbsa_bconfig (*FUNCTION_NAME(g_signal_hlbsa_bconfig,gsignal)())

#define g_class_closure_bconfig (*FUNCTION_NAME(g_class_closure_bconfig,gsignal)())

#define g_handler_list_bsa_ht (*FUNCTION_NAME(g_handler_list_bsa_ht,gsignal)())

#define g_recursive_emissions (*FUNCTION_NAME(g_recursive_emissions,gsignal)())

#define g_restart_emissions  (*FUNCTION_NAME(g_restart_emissions ,gsignal)())

#define g_handler_sequential_number  (*FUNCTION_NAME(g_handler_sequential_number ,gsignal)())

#define g__g_signal_mutex_lock (*FUNCTION_NAME_MACRO(g_signal_mutex,gsignal)())

#define g_n_signal_nodes (*FUNCTION_NAME(g_n_signal_nodes,gsignal)())

#define g_signal_nodes (*FUNCTION_NAME(g_signal_nodes,gsignal)())

const GBSearchConfig temp_g_signal_hlbsa_bconfig = {

  sizeof (HandlerList),

  handler_lists_cmp,

  0,

};

 const GBSearchConfig temp_g_class_closure_bconfig = {

  sizeof (ClassClosure),

  class_closures_cmp,

  0,

};

#else

static GBSearchArray *g_signal_key_bsa = NULL;

#endif//EMULATOR

static const GBSearchConfig g_signal_key_bconfig = {

  sizeof (SignalKey),

  signal_key_cmp,

  G_BSEARCH_ARRAY_ALIGN_POWER2,

};

#if (!EMULATOR)

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 gulong         g_handler_sequential_number = 1;

G_LOCK_DEFINE_STATIC (g_signal_mutex);

#endif//EMULATOR

#define	SIGNAL_LOCK()		G_LOCK (g_signal_mutex)

#define	SIGNAL_UNLOCK()		G_UNLOCK (g_signal_mutex)

/* --- signal nodes --- */

#if (!EMULATOR)

static guint          g_n_signal_nodes = 0;

static SignalNode   **g_signal_nodes = NULL;

#endif /* EMULATOR */

static inline SignalNode*

LOOKUP_SIGNAL_NODE (register guint signal_id)

{

  if (signal_id < g_n_signal_nodes)

    return g_signal_nodes[signal_id];

  else

    return NULL;

}

/* --- functions --- */

static inline guint

signal_id_lookup (GQuark quark,

		  GType  itype)

{

  GType *ifaces, type = itype;

  SignalKey key;

  guint n_ifaces;

  key.quark = quark;

  /* 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, &g_signal_key_bconfig, &key);

      if (signal_key)

	return signal_key->signal_id;

      type = g_type_parent (type);

    }

  while (type);

  /* no luck, try interfaces it exports */

  ifaces = g_type_interfaces (itype, &n_ifaces);

  while (n_ifaces--)

    {

      SignalKey *signal_key;

      key.itype = ifaces[n_ifaces];

      signal_key = g_bsearch_array_lookup (g_signal_key_bsa, &g_signal_key_bconfig, &key);

      if (signal_key)

	{

	  g_free (ifaces);

	  return signal_key->signal_id;

	}

    }

  g_free (ifaces);

  return 0;

}

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)

{

  const HandlerList *hlist1 = node1, *hlist2 = node2;

  return G_BSEARCH_ARRAY_CMP (hlist1->signal_id, hlist2->signal_id);

}

static inline HandlerList*

handler_list_ensure (guint    signal_id,

		     gpointer instance)

{

  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_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);

    }

  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*

handler_list_lookup (guint    signal_id,

		     gpointer instance)

{

  GBSearchArray *hlbsa = g_hash_table_lookup (g_handler_list_bsa_ht, instance);

  HandlerList key;

  key.signal_id = signal_id;

  return hlbsa ? g_bsearch_array_lookup (hlbsa, &g_signal_hlbsa_bconfig, &key) : NULL;

}

static Handler*

handler_lookup (gpointer instance,

		gulong   handler_id,

		guint   *signal_id_p)

{

  GBSearchArray *hlbsa = g_hash_table_lookup (g_handler_list_bsa_ht, instance);

  if (hlbsa)

    {

      guint i;

      for (i = 0; i < hlbsa->n_nodes; 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->sequential_number == handler_id)

              {

                if (signal_id_p)

                  *signal_id_p = hlist->signal_id;

                return handler;

              }

        }

    }

  return NULL;

}

static inline HandlerMatch*

handler_match_prepend (HandlerMatch *list,

		       Handler      *handler,

		       guint	     signal_id)

{

  HandlerMatch *node;

  node = g_slice_new (HandlerMatch);

  node->handler = handler;

  node->next = list;

  node->signal_id = signal_id;

  handler_ref (handler);

  return node;

}

static inline HandlerMatch*

handler_match_free1_R (HandlerMatch *node,

		       gpointer      instance)

{

  HandlerMatch *next = node->next;

  handler_unref_R (node->signal_id, instance, node->handler);

  g_slice_free (HandlerMatch, node);

  return next;