glib/gobject/gsourceclosure.c

/* GObject - GLib Type, Object, Parameter and Signal Library
 * Copyright (C) 2001 Red Hat, Inc.
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * 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 2.1 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, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include "gsourceclosure.h"
#include "gboxed.h"
#include "genums.h"
#include "gmarshal.h"
#include "gvalue.h"
#include "gvaluetypes.h"
#ifdef G_OS_UNIX
#include "glib-unix.h"
#endif

G_DEFINE_BOXED_TYPE (GIOChannel, g_io_channel, g_io_channel_ref, g_io_channel_unref)

GType
g_io_condition_get_type (void)
{
  static GType etype = 0;

  if (g_once_init_enter_pointer (&etype))
    {
      static const GFlagsValue values[] = {
	{ G_IO_IN,   "G_IO_IN",   "in" },
	{ G_IO_OUT,  "G_IO_OUT",  "out" },
	{ G_IO_PRI,  "G_IO_PRI",  "pri" },
	{ G_IO_ERR,  "G_IO_ERR",  "err" },
	{ G_IO_HUP,  "G_IO_HUP",  "hup" },
	{ G_IO_NVAL, "G_IO_NVAL", "nval" },
	{ 0, NULL, NULL }
      };
      GType type_id = g_flags_register_static ("GIOCondition", values);
      g_once_init_leave_pointer (&etype, type_id);
    }
  return etype;
}

/* We need to hand-write this marshaler, since it doesn't have an
 * instance object.
 */
static void
source_closure_marshal_BOOLEAN__VOID (GClosure     *closure,
				      GValue       *return_value,
				      guint         n_param_values,
				      const GValue *param_values,
				      gpointer      invocation_hint,
				      gpointer      marshal_data)
{
  GSourceFunc callback;
  GCClosure *cc = (GCClosure*) closure;
  gboolean v_return;

  g_return_if_fail (return_value != NULL);
  g_return_if_fail (n_param_values == 0);

  callback = (GSourceFunc) (marshal_data ? marshal_data : cc->callback);

  v_return = callback (closure->data);

  g_value_set_boolean (return_value, v_return);
}

static gboolean
io_watch_closure_callback (GIOChannel   *channel,
			   GIOCondition  condition,
			   gpointer      data)
{
  GClosure *closure = data;

  GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
  GValue result_value = G_VALUE_INIT;
  gboolean result;

  g_value_init (&result_value, G_TYPE_BOOLEAN);
  g_value_init (&params[0], G_TYPE_IO_CHANNEL);
  g_value_set_boxed (&params[0], channel);
		     
  g_value_init (&params[1], G_TYPE_IO_CONDITION);
  g_value_set_flags (&params[1], condition);

  g_closure_invoke (closure, &result_value, 2, params, NULL);

  result = g_value_get_boolean (&result_value);
  g_value_unset (&result_value);
  g_value_unset (&params[0]);
  g_value_unset (&params[1]);

  return result;
}

static gboolean
g_child_watch_closure_callback (GPid     pid,
                                gint     status,
                                gpointer data)
{
  GClosure *closure = data;

  GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
  GValue result_value = G_VALUE_INIT;
  gboolean result;

  g_value_init (&result_value, G_TYPE_BOOLEAN);

#ifdef G_OS_UNIX
  g_value_init (&params[0], G_TYPE_ULONG);
  G_STATIC_ASSERT (sizeof (pid) <= sizeof (unsigned long));
  g_value_set_ulong (&params[0], (gulong) pid);
#endif
#ifdef G_OS_WIN32
  g_value_init (&params[0], G_TYPE_POINTER);
  g_value_set_pointer (&params[0], pid);
#endif

  g_value_init (&params[1], G_TYPE_INT);
  g_value_set_int (&params[1], status);

  g_closure_invoke (closure, &result_value, 2, params, NULL);

  result = g_value_get_boolean (&result_value);
  g_value_unset (&result_value);
  g_value_unset (&params[0]);
  g_value_unset (&params[1]);

  return result;
}

#ifdef G_OS_UNIX
static gboolean
g_unix_fd_source_closure_callback (int           fd,
                                   GIOCondition  condition,
                                   gpointer      data)
{
  GClosure *closure = data;

  GValue params[2] = { G_VALUE_INIT, G_VALUE_INIT };
  GValue result_value = G_VALUE_INIT;
  gboolean result;

  g_value_init (&result_value, G_TYPE_BOOLEAN);

  g_value_init (&params[0], G_TYPE_INT);
  g_value_set_int (&params[0], fd);

  g_value_init (&params[1], G_TYPE_IO_CONDITION);
  g_value_set_flags (&params[1], condition);

  g_closure_invoke (closure, &result_value, 2, params, NULL);

  result = g_value_get_boolean (&result_value);
  g_value_unset (&result_value);
  g_value_unset (&params[0]);
  g_value_unset (&params[1]);

  return result;
}
#endif

static gboolean
source_closure_callback (gpointer data)
{
  GClosure *closure = data;
  GValue result_value = G_VALUE_INIT;
  gboolean result;

  g_value_init (&result_value, G_TYPE_BOOLEAN);
  
  g_closure_invoke (closure, &result_value, 0, NULL, NULL);

  result = g_value_get_boolean (&result_value);
  g_value_unset (&result_value);

  return result;
}

static void
closure_callback_get (gpointer     cb_data,
		      GSource     *source,
		      GSourceFunc *func,
		      gpointer    *data)
{
  GSourceFunc closure_callback = source->source_funcs->closure_callback;

  if (!closure_callback)
    {
      if (source->source_funcs == &g_io_watch_funcs)
        closure_callback = (GSourceFunc)io_watch_closure_callback;
      else if (source->source_funcs == &g_child_watch_funcs)
        closure_callback = (GSourceFunc)g_child_watch_closure_callback;
#ifdef G_OS_UNIX
      else if (source->source_funcs == &g_unix_fd_source_funcs)
        closure_callback = (GSourceFunc)g_unix_fd_source_closure_callback;
#endif
      else if (source->source_funcs == &g_timeout_funcs ||
#ifdef G_OS_UNIX
               source->source_funcs == &g_unix_signal_funcs ||
#endif
               source->source_funcs == &g_idle_funcs)
        closure_callback = source_closure_callback;
    }

  *func = closure_callback;
  *data = cb_data;
}

static GSourceCallbackFuncs closure_callback_funcs = {
  (void (*) (gpointer)) g_closure_ref,
  (void (*) (gpointer)) g_closure_unref,
  closure_callback_get
};

static void
closure_invalidated (gpointer  user_data,
                     GClosure *closure)
{
  g_source_destroy (user_data);
}

/**
 * g_source_set_closure:
 * @source: the source
 * @closure: a #GClosure
 *
 * Set the callback for a source as a #GClosure.
 *
 * If the source is not one of the standard GLib types, the @closure_callback
 * and @closure_marshal fields of the #GSourceFuncs structure must have been
 * filled in with pointers to appropriate functions.
 */
void
g_source_set_closure (GSource  *source,
		      GClosure *closure)
{
  g_return_if_fail (source != NULL);
  g_return_if_fail (closure != NULL);

  if (!source->source_funcs->closure_callback &&
#ifdef G_OS_UNIX
      source->source_funcs != &g_unix_fd_source_funcs &&
      source->source_funcs != &g_unix_signal_funcs &&
#endif
      source->source_funcs != &g_child_watch_funcs &&
      source->source_funcs != &g_io_watch_funcs &&
      source->source_funcs != &g_timeout_funcs &&
      source->source_funcs != &g_idle_funcs)
    {
      g_critical (G_STRLOC ": closure cannot be set on GSource without GSourceFuncs::closure_callback");
      return;
    }

  g_closure_ref (closure);
  g_closure_sink (closure);
  g_source_set_callback_indirect (source, closure, &closure_callback_funcs);

  g_closure_add_invalidate_notifier (closure, source, closure_invalidated);

  if (G_CLOSURE_NEEDS_MARSHAL (closure))
    {
      GClosureMarshal marshal = (GClosureMarshal)source->source_funcs->closure_marshal;
      if (marshal)
	g_closure_set_marshal (closure, marshal);
      else if (source->source_funcs == &g_idle_funcs ||
#ifdef G_OS_UNIX
               source->source_funcs == &g_unix_signal_funcs ||
#endif
               source->source_funcs == &g_timeout_funcs)
	g_closure_set_marshal (closure, source_closure_marshal_BOOLEAN__VOID);
      else
        g_closure_set_marshal (closure, g_cclosure_marshal_generic);
    }
}

static void
dummy_closure_marshal (GClosure     *closure,
		       GValue       *return_value,
		       guint         n_param_values,
		       const GValue *param_values,
		       gpointer      invocation_hint,
		       gpointer      marshal_data)
{
  if (G_VALUE_HOLDS_BOOLEAN (return_value))
    g_value_set_boolean (return_value, TRUE);
}

/**
 * g_source_set_dummy_callback:
 * @source: the source
 *
 * Sets a dummy callback for @source. The callback will do nothing, and
 * if the source expects a #gboolean return value, it will return %TRUE.
 * (If the source expects any other type of return value, it will return
 * a 0/%NULL value; whatever g_value_init() initializes a #GValue to for
 * that type.)
 *
 * If the source is not one of the standard GLib types, the
 * @closure_callback and @closure_marshal fields of the #GSourceFuncs
 * structure must have been filled in with pointers to appropriate
 * functions.
 */
void
g_source_set_dummy_callback (GSource *source)
{
  GClosure *closure;

  closure = g_closure_new_simple (sizeof (GClosure), NULL);
  g_closure_set_meta_marshal (closure, NULL, dummy_closure_marshal);
  g_source_set_closure (source, closure);
}