/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* gthread.c: MT safety related functions
* Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
* Owen Taylor
*
* 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.
*/
#include "config.h"
/* we know we are deprecated here, no need for warnings */
#define GLIB_DISABLE_DEPRECATION_WARNINGS
#include "gmessages.h"
#include "gslice.h"
#include "gmain.h"
#include "gthread.h"
#include "gthreadprivate.h"
#include "deprecated/gthread.h"
#include "garray.h"
#include "gutils.h"
/* {{{1 Documentation */
/**
* SECTION:threads-deprecated
* @title: Deprecated thread API
* @short_description: old thread APIs (for reference only)
* @see_also: #GThread
*
* These APIs are deprecated. You should not use them in new code.
* This section remains only to assist with understanding code that was
* written to use these APIs at some point in the past.
**/
/**
* GThreadPriority:
* @G_THREAD_PRIORITY_LOW: a priority lower than normal
* @G_THREAD_PRIORITY_NORMAL: the default priority
* @G_THREAD_PRIORITY_HIGH: a priority higher than normal
* @G_THREAD_PRIORITY_URGENT: the highest priority
*
* Deprecated:2.32: Thread priorities no longer have any effect.
*/
/**
* GThreadFunctions:
* @mutex_new: virtual function pointer for g_mutex_new()
* @mutex_lock: virtual function pointer for g_mutex_lock()
* @mutex_trylock: virtual function pointer for g_mutex_trylock()
* @mutex_unlock: virtual function pointer for g_mutex_unlock()
* @mutex_free: virtual function pointer for g_mutex_free()
* @cond_new: virtual function pointer for g_cond_new()
* @cond_signal: virtual function pointer for g_cond_signal()
* @cond_broadcast: virtual function pointer for g_cond_broadcast()
* @cond_wait: virtual function pointer for g_cond_wait()
* @cond_timed_wait: virtual function pointer for g_cond_timed_wait()
* @cond_free: virtual function pointer for g_cond_free()
* @private_new: virtual function pointer for g_private_new()
* @private_get: virtual function pointer for g_private_get()
* @private_set: virtual function pointer for g_private_set()
* @thread_create: virtual function pointer for g_thread_create()
* @thread_yield: virtual function pointer for g_thread_yield()
* @thread_join: virtual function pointer for g_thread_join()
* @thread_exit: virtual function pointer for g_thread_exit()
* @thread_set_priority: virtual function pointer for
* g_thread_set_priority()
* @thread_self: virtual function pointer for g_thread_self()
* @thread_equal: used internally by recursive mutex locks and by some
* assertion checks
*
* This function table is no longer used by g_thread_init()
* to initialize the thread system.
*/
/**
* G_THREADS_IMPL_POSIX:
*
* This macro is defined if POSIX style threads are used.
*
* Deprecated:2.32:POSIX threads are in use on all non-Windows systems.
* Use G_OS_WIN32 to detect Windows.
*/
/**
* G_THREADS_IMPL_WIN32:
*
* This macro is defined if Windows style threads are used.
*
* Deprecated:2.32:Use G_OS_WIN32 to detect Windows.
*/
/* {{{1 Exported Variables */
/* Set this FALSE to have previously-compiled GStaticMutex code use the
* slow path (ie: call into us) to avoid compatibility problems.
*/
gboolean g_thread_use_default_impl = FALSE;
GThreadFunctions g_thread_functions_for_glib_use =
{
g_mutex_new,
g_mutex_lock,
g_mutex_trylock,
g_mutex_unlock,
g_mutex_free,
g_cond_new,
g_cond_signal,
g_cond_broadcast,
g_cond_wait,
g_cond_timed_wait,
g_cond_free,
g_private_new,
g_private_get,
g_private_set,
NULL,
g_thread_yield,
NULL,
NULL,
NULL,
NULL,
NULL,
};
static guint64
gettime (void)
{
return g_get_monotonic_time () * 1000;
}
guint64 (*g_thread_gettime) (void) = gettime;
/* Initialisation {{{1 ---------------------------------------------------- */
gboolean g_threads_got_initialized = TRUE;
/**
* g_thread_init:
* @vtable: a function table of type #GThreadFunctions, that provides
* the entry points to the thread system to be used. Since 2.32,
* this parameter is ignored and should always be %NULL
*
* If you use GLib from more than one thread, you must initialize the
* thread system by calling g_thread_init().
*
* Since version 2.24, calling g_thread_init() multiple times is allowed,
* but nothing happens except for the first call.
*
* Since version 2.32, GLib does not support custom thread implementations
* anymore and the @vtable parameter is ignored and you should pass %NULL.
*
* g_thread_init() must not be called directly or indirectly
* in a callback from GLib. Also no mutexes may be currently locked while
* calling g_thread_init().
*
* To use g_thread_init() in your program, you have to link
* with the libraries that the command pkg-config --libs
* gthread-2.0 outputs. This is not the case for all the
* other thread-related functions of GLib. Those can be used without
* having to link with the thread libraries.
*
* Deprecated:2.32: This function is no longer necessary. The GLib
* threading system is automatically initialized at the start
* of your program.
*/
/**
* g_thread_get_initialized:
*
* Indicates if g_thread_init() has been called.
*
* Returns: %TRUE if threads have been initialized.
*
* Since: 2.20
*/
gboolean
g_thread_get_initialized (void)
{
return g_thread_supported ();
}
/* We need this for ABI compatibility */
void g_thread_init_glib (void);
void g_thread_init_glib (void) { }
/* Internal variables {{{1 */
static GSList *g_thread_all_threads = NULL;
static GSList *g_thread_free_indices = NULL;
/* Protects g_thread_all_threads and g_thread_free_indices */
G_LOCK_DEFINE_STATIC (g_static_mutex);
G_LOCK_DEFINE_STATIC (g_thread);
/* Misc. GThread functions {{{1 */
/**
* g_thread_set_priority:
* @thread: a #GThread.
* @priority: ignored
*
* This function does nothing.
*
* Deprecated:2.32: Thread priorities no longer have any effect.
*/
void
g_thread_set_priority (GThread *thread,
GThreadPriority priority)
{
}
/**
* g_thread_foreach:
* @thread_func: function to call for all #GThread structures
* @user_data: second argument to @thread_func
*
* Call @thread_func on all #GThreads that have been
* created with g_thread_create().
*
* Note that threads may decide to exit while @thread_func is
* running, so without intimate knowledge about the lifetime of
* foreign threads, @thread_func shouldn't access the GThread*
* pointer passed in as first argument. However, @thread_func will
* not be called for threads which are known to have exited already.
*
* Due to thread lifetime checks, this function has an execution complexity
* which is quadratic in the number of existing threads.
*
* Since: 2.10
*
* Deprecated:2.32: There aren't many things you can do with a #GThread,
* except comparing it with one that was returned from g_thread_create().
* There are better ways to find out if your thread is still alive.
*/
void
g_thread_foreach (GFunc thread_func,
gpointer user_data)
{
GSList *slist = NULL;
GRealThread *thread;
g_return_if_fail (thread_func != NULL);
/* snapshot the list of threads for iteration */
G_LOCK (g_thread);
slist = g_slist_copy (g_thread_all_threads);
G_UNLOCK (g_thread);
/* walk the list, skipping non-existent threads */
while (slist)
{
GSList *node = slist;
slist = node->next;
/* check whether the current thread still exists */
G_LOCK (g_thread);
if (g_slist_find (g_thread_all_threads, node->data))
thread = node->data;
else
thread = NULL;
G_UNLOCK (g_thread);
if (thread)
thread_func (thread, user_data);
g_slist_free_1 (node);
}
}
static void
g_enumerable_thread_remove (gpointer data)
{
GRealThread *thread = data;
G_LOCK (g_thread);
g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
G_UNLOCK (g_thread);
}
GPrivate enumerable_thread_private = G_PRIVATE_INIT (g_enumerable_thread_remove);
static void
g_enumerable_thread_add (GRealThread *thread)
{
G_LOCK (g_thread);
g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
G_UNLOCK (g_thread);
g_private_set (&enumerable_thread_private, thread);
}
static gpointer
g_deprecated_thread_proxy (gpointer data)
{
GRealThread *real = data;
g_enumerable_thread_add (real);
return g_thread_proxy (data);
}
/**
* g_thread_create:
* @func: a function to execute in the new thread
* @data: an argument to supply to the new thread
* @joinable: should this thread be joinable?
* @error: return location for error, or %NULL
*
* This function creates a new thread.
*
* The new thread executes the function @func with the argument @data.
* If the thread was created successfully, it is returned.
*
* @error can be %NULL to ignore errors, or non-%NULL to report errors.
* The error is set, if and only if the function returns %NULL.
*
* This function returns a reference to the created thread only if
* @joinable is %TRUE. In that case, you must free this reference by
* calling g_thread_unref() or g_thread_join(). If @joinable is %FALSE
* then you should probably not touch the return value.
*
* Returns: the new #GThread on success
*
* Deprecated:2.32: Use g_thread_new() instead
*/
GThread *
g_thread_create (GThreadFunc func,
gpointer data,
gboolean joinable,
GError **error)
{
return g_thread_create_full (func, data, 0, joinable, 0, 0, error);
}
/**
* g_thread_create_full:
* @func: a function to execute in the new thread.
* @data: an argument to supply to the new thread.
* @stack_size: a stack size for the new thread.
* @joinable: should this thread be joinable?
* @bound: ignored
* @priority: ignored
* @error: return location for error.
* @Returns: the new #GThread on success.
*
* This function creates a new thread.
*
* Deprecated:2.32: The @bound and @priority arguments are now ignored.
* Use g_thread_new().
*/
GThread *
g_thread_create_full (GThreadFunc func,
gpointer data,
gulong stack_size,
gboolean joinable,
gboolean bound,
GThreadPriority priority,
GError **error)
{
GThread *thread;
thread = g_thread_new_internal (NULL, g_deprecated_thread_proxy,
func, data, stack_size, error);
if (!joinable)
{
thread->joinable = FALSE;
g_thread_unref (thread);
}
return thread;
}
/* GOnce {{{1 ------------------------------------------------------------- */
gboolean
g_once_init_enter_impl (volatile gsize *location)
{
return (g_once_init_enter) (location);
}
/* GStaticMutex {{{1 ------------------------------------------------------ */
/**
* GStaticMutex:
*
* A #GStaticMutex works like a #GMutex.
*
* Prior to GLib 2.32, GStaticMutex had the significant advantage
* that it doesn't need to be created at run-time, but can be defined
* at compile-time. Since 2.32, #GMutex can be statically allocated
* as well, and GStaticMutex has been deprecated.
*
* Here is a version of our give_me_next_number() example using
* a GStaticMutex.
*
*
*
* Using <structname>GStaticMutex</structname>
* to simplify thread-safe programming
*
*
* int
* give_me_next_number (void)
* {
* static int current_number = 0;
* int ret_val;
* static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
*
* g_static_mutex_lock (&mutex);
* ret_val = current_number = calc_next_number (current_number);
* g_static_mutex_unlock (&mutex);
*
* return ret_val;
* }
*
*
*
* Sometimes you would like to dynamically create a mutex. If you don't
* want to require prior calling to g_thread_init(), because your code
* should also be usable in non-threaded programs, you are not able to
* use g_mutex_new() and thus #GMutex, as that requires a prior call to
* g_thread_init(). In theses cases you can also use a #GStaticMutex.
* It must be initialized with g_static_mutex_init() before using it
* and freed with with g_static_mutex_free() when not needed anymore to
* free up any allocated resources.
*
* Even though #GStaticMutex is not opaque, it should only be used with
* the following functions, as it is defined differently on different
* platforms.
*
* All of the g_static_mutex_* functions apart
* from g_static_mutex_get_mutex can also be used
* even if g_thread_init() has not yet been called. Then they do
* nothing, apart from g_static_mutex_trylock,
* which does nothing but returning %TRUE.
*
* All of the g_static_mutex_*
* functions are actually macros. Apart from taking their addresses, you
* can however use them as if they were functions.
**/
/**
* G_STATIC_MUTEX_INIT:
*
* A #GStaticMutex must be initialized with this macro, before it can
* be used. This macro can used be to initialize a variable, but it
* cannot be assigned to a variable. In that case you have to use
* g_static_mutex_init().
*
* |[
* GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
* ]|
**/
/**
* g_static_mutex_init:
* @mutex: a #GStaticMutex to be initialized.
*
* Initializes @mutex.
* Alternatively you can initialize it with #G_STATIC_MUTEX_INIT.
*
* Deprecated: 2.32: Use g_mutex_init()
*/
void
g_static_mutex_init (GStaticMutex *mutex)
{
static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
g_return_if_fail (mutex);
*mutex = init_mutex;
}
/* IMPLEMENTATION NOTE:
*
* On some platforms a GStaticMutex is actually a normal GMutex stored
* inside of a structure instead of being allocated dynamically. We can
* only do this for platforms on which we know, in advance, how to
* allocate (size) and initialise (value) that memory.
*
* On other platforms, a GStaticMutex is nothing more than a pointer to
* a GMutex. In that case, the first access we make to the static mutex
* must first allocate the normal GMutex and store it into the pointer.
*
* configure.ac writes macros into glibconfig.h to determine if
* g_static_mutex_get_mutex() accesses the structure in memory directly
* (on platforms where we are able to do that) or if it ends up here,
* where we may have to allocate the GMutex before returning it.
*/
/**
* g_static_mutex_get_mutex:
* @mutex: a #GStaticMutex.
* @Returns: the #GMutex corresponding to @mutex.
*
* For some operations (like g_cond_wait()) you must have a #GMutex
* instead of a #GStaticMutex. This function will return the
* corresponding #GMutex for @mutex.
*
* Deprecated: 2.32: Just use a #GMutex
*/
GMutex *
g_static_mutex_get_mutex_impl (GStaticMutex* mutex)
{
GMutex *result;
if (!g_thread_supported ())
return NULL;
result = g_atomic_pointer_get (&mutex->mutex);
if (!result)
{
G_LOCK (g_static_mutex);
result = mutex->mutex;
if (!result)
{
result = g_mutex_new ();
g_atomic_pointer_set (&mutex->mutex, result);
}
G_UNLOCK (g_static_mutex);
}
return result;
}
/* IMPLEMENTATION NOTE:
*
* g_static_mutex_lock(), g_static_mutex_trylock() and
* g_static_mutex_unlock() are all preprocessor macros that wrap the
* corresponding g_mutex_*() function around a call to
* g_static_mutex_get_mutex().
*/
/**
* g_static_mutex_lock:
* @mutex: a #GStaticMutex.
*
* Works like g_mutex_lock(), but for a #GStaticMutex.
*
* Deprecated: 2.32: Use g_mutex_lock()
*/
/**
* g_static_mutex_trylock:
* @mutex: a #GStaticMutex.
* @Returns: %TRUE, if the #GStaticMutex could be locked.
*
* Works like g_mutex_trylock(), but for a #GStaticMutex.
*
* Deprecated: 2.32: Use g_mutex_trylock()
*/
/**
* g_static_mutex_unlock:
* @mutex: a #GStaticMutex.
*
* Works like g_mutex_unlock(), but for a #GStaticMutex.
*
* Deprecated: 2.32: Use g_mutex_unlock()
*/
/**
* g_static_mutex_free:
* @mutex: a #GStaticMutex to be freed.
*
* Releases all resources allocated to @mutex.
*
* You don't have to call this functions for a #GStaticMutex with an
* unbounded lifetime, i.e. objects declared 'static', but if you have
* a #GStaticMutex as a member of a structure and the structure is
* freed, you should also free the #GStaticMutex.
*
* Calling g_static_mutex_free() on a locked mutex may
* result in undefined behaviour.
*
* Deprecated: 2.32: Use g_mutex_free()
*/
void
g_static_mutex_free (GStaticMutex* mutex)
{
GMutex **runtime_mutex;
g_return_if_fail (mutex);
/* The runtime_mutex is the first (or only) member of GStaticMutex,
* see both versions (of glibconfig.h) in configure.ac. Note, that
* this variable is NULL, if g_thread_init() hasn't been called or
* if we're using the default thread implementation and it provides
* static mutexes. */
runtime_mutex = ((GMutex**)mutex);
if (*runtime_mutex)
g_mutex_free (*runtime_mutex);
*runtime_mutex = NULL;
}
/* {{{1 GStaticRecMutex */
/**
* GStaticRecMutex:
*
* A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
* multiple times by one thread. If you enter it n times, you have to
* unlock it n times again to let other threads lock it. An exception
* is the function g_static_rec_mutex_unlock_full(): that allows you to
* unlock a #GStaticRecMutex completely returning the depth, (i.e. the
* number of times this mutex was locked). The depth can later be used
* to restore the state of the #GStaticRecMutex by calling
* g_static_rec_mutex_lock_full(). In GLib 2.32, #GStaticRecMutex has
* been deprecated in favor of #GRecMutex.
*
* Even though #GStaticRecMutex is not opaque, it should only be used
* with the following functions.
*
* All of the g_static_rec_mutex_* functions can
* be used even if g_thread_init() has not been called. Then they do
* nothing, apart from g_static_rec_mutex_trylock,
* which does nothing but returning %TRUE.
**/
/**
* G_STATIC_REC_MUTEX_INIT:
*
* A #GStaticRecMutex must be initialized with this macro before it can
* be used. This macro can used be to initialize a variable, but it
* cannot be assigned to a variable. In that case you have to use
* g_static_rec_mutex_init().
*
* |[
* GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
* ]|
*/
/**
* g_static_rec_mutex_init:
* @mutex: a #GStaticRecMutex to be initialized.
*
* A #GStaticRecMutex must be initialized with this function before it
* can be used. Alternatively you can initialize it with
* #G_STATIC_REC_MUTEX_INIT.
*
* Deprecated: 2.32: Use g_rec_mutex_init()
*/
void
g_static_rec_mutex_init (GStaticRecMutex *mutex)
{
static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
g_return_if_fail (mutex);
*mutex = init_mutex;
}
static GRecMutex *
g_static_rec_mutex_get_rec_mutex_impl (GStaticRecMutex* mutex)
{
GRecMutex *result;
if (!g_thread_supported ())
return NULL;
result = g_atomic_pointer_get (&mutex->mutex.mutex);
if (!result)
{
G_LOCK (g_static_mutex);
result = (GRecMutex *) mutex->mutex.mutex;
if (!result)
{
result = g_slice_new (GRecMutex);
g_rec_mutex_init (result);
g_atomic_pointer_set (&mutex->mutex.mutex, result);
}
G_UNLOCK (g_static_mutex);
}
return result;
}
/**
* g_static_rec_mutex_lock:
* @mutex: a #GStaticRecMutex to lock.
*
* Locks @mutex. If @mutex is already locked by another thread, the
* current thread will block until @mutex is unlocked by the other
* thread. If @mutex is already locked by the calling thread, this
* functions increases the depth of @mutex and returns immediately.
*
* Deprecated: 2.32: Use g_rec_mutex_lock()
*/
void
g_static_rec_mutex_lock (GStaticRecMutex* mutex)
{
GRecMutex *rm;
rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
g_rec_mutex_lock (rm);
mutex->depth++;
}
/**
* g_static_rec_mutex_trylock:
* @mutex: a #GStaticRecMutex to lock.
* @Returns: %TRUE, if @mutex could be locked.
*
* Tries to lock @mutex. If @mutex is already locked by another thread,
* it immediately returns %FALSE. Otherwise it locks @mutex and returns
* %TRUE. If @mutex is already locked by the calling thread, this
* functions increases the depth of @mutex and immediately returns
* %TRUE.
*
* Deprecated: 2.32: Use g_rec_mutex_trylock()
*/
gboolean
g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
{
GRecMutex *rm;
rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
if (g_rec_mutex_trylock (rm))
{
mutex->depth++;
return TRUE;
}
else
return FALSE;
}
/**
* g_static_rec_mutex_unlock:
* @mutex: a #GStaticRecMutex to unlock.
*
* Unlocks @mutex. Another thread will be allowed to lock @mutex only
* when it has been unlocked as many times as it had been locked
* before. If @mutex is completely unlocked and another thread is
* blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
* woken and can lock @mutex itself.
*
* Deprecated: 2.32: Use g_rec_mutex_unlock()
*/
void
g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
{
GRecMutex *rm;
rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
mutex->depth--;
g_rec_mutex_unlock (rm);
}
/**
* g_static_rec_mutex_lock_full:
* @mutex: a #GStaticRecMutex to lock.
* @depth: number of times this mutex has to be unlocked to be
* completely unlocked.
*
* Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
*
* Deprecated: 2.32: Use g_rec_mutex_lock()
*/
void
g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
guint depth)
{
GRecMutex *rm;
rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
while (depth--)
{
g_rec_mutex_lock (rm);
mutex->depth++;
}
}
/**
* g_static_rec_mutex_unlock_full:
* @mutex: a #GStaticRecMutex to completely unlock.
* @Returns: number of times @mutex has been locked by the current
* thread.
*
* Completely unlocks @mutex. If another thread is blocked in a
* g_static_rec_mutex_lock() call for @mutex, it will be woken and can
* lock @mutex itself. This function returns the number of times that
* @mutex has been locked by the current thread. To restore the state
* before the call to g_static_rec_mutex_unlock_full() you can call
* g_static_rec_mutex_lock_full() with the depth returned by this
* function.
*
* Deprecated: 2.32: Use g_rec_mutex_unlock()
*/
guint
g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
{
GRecMutex *rm;
gint depth;
gint i;
rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
/* all access to mutex->depth done while still holding the lock */
depth = mutex->depth;
i = mutex->depth;
mutex->depth = 0;
while (i--)
g_rec_mutex_unlock (rm);
return depth;
}
/**
* g_static_rec_mutex_free:
* @mutex: a #GStaticRecMutex to be freed.
*
* Releases all resources allocated to a #GStaticRecMutex.
*
* You don't have to call this functions for a #GStaticRecMutex with an
* unbounded lifetime, i.e. objects declared 'static', but if you have
* a #GStaticRecMutex as a member of a structure and the structure is
* freed, you should also free the #GStaticRecMutex.
*
* Deprecated: 2.32: Use g_rec_mutex_clear()
*/
void
g_static_rec_mutex_free (GStaticRecMutex *mutex)
{
g_return_if_fail (mutex);
if (mutex->mutex.mutex)
{
GRecMutex *rm = (GRecMutex *) mutex->mutex.mutex;
g_rec_mutex_clear (rm);
g_slice_free (GRecMutex, rm);
}
}
/* GStaticRWLock {{{1 ----------------------------------------------------- */
/**
* GStaticRWLock:
*
* The #GStaticRWLock struct represents a read-write lock. A read-write
* lock can be used for protecting data that some portions of code only
* read from, while others also write. In such situations it is
* desirable that several readers can read at once, whereas of course
* only one writer may write at a time. Take a look at the following
* example:
*
*
* An array with access functions
*
* GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
* GPtrArray *array;
*
* gpointer
* my_array_get (guint index)
* {
* gpointer retval = NULL;
*
* if (!array)
* return NULL;
*
* g_static_rw_lock_reader_lock (&rwlock);
* if (index < array->len)
* retval = g_ptr_array_index (array, index);
* g_static_rw_lock_reader_unlock (&rwlock);
*
* return retval;
* }
*
* void
* my_array_set (guint index, gpointer data)
* {
* g_static_rw_lock_writer_lock (&rwlock);
*
* if (!array)
* array = g_ptr_array_new ();
*
* if (index >= array->len)
* g_ptr_array_set_size (array, index+1);
* g_ptr_array_index (array, index) = data;
*
* g_static_rw_lock_writer_unlock (&rwlock);
* }
*
*
*
* This example shows an array which can be accessed by many readers
* (the my_array_get() function) simultaneously,
* whereas the writers (the my_array_set()
* function) will only be allowed once at a time and only if no readers
* currently access the array. This is because of the potentially
* dangerous resizing of the array. Using these functions is fully
* multi-thread safe now.
*
* Most of the time, writers should have precedence over readers. That
* means, for this implementation, that as soon as a writer wants to
* lock the data, no other reader is allowed to lock the data, whereas,
* of course, the readers that already have locked the data are allowed
* to finish their operation. As soon as the last reader unlocks the
* data, the writer will lock it.
*
* Even though #GStaticRWLock is not opaque, it should only be used
* with the following functions.
*
* All of the g_static_rw_lock_* functions can be
* used even if g_thread_init() has not been called. Then they do
* nothing, apart from g_static_rw_lock_*_trylock,
* which does nothing but returning %TRUE.
*
* A read-write lock has a higher overhead than a mutex. For
* example, both g_static_rw_lock_reader_lock() and
* g_static_rw_lock_reader_unlock() have to lock and unlock a
* #GStaticMutex, so it takes at least twice the time to lock and unlock
* a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
* only data structures that are accessed by multiple readers, and which
* keep the lock for a considerable time justify a #GStaticRWLock. The
* above example most probably would fare better with a
* #GStaticMutex.
*
* Deprecated: 2.32: Use a #GRWLock instead
**/
/**
* G_STATIC_RW_LOCK_INIT:
*
* A #GStaticRWLock must be initialized with this macro before it can
* be used. This macro can used be to initialize a variable, but it
* cannot be assigned to a variable. In that case you have to use
* g_static_rw_lock_init().
*
* |[
* GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
* ]|
*/
/**
* g_static_rw_lock_init:
* @lock: a #GStaticRWLock to be initialized.
*
* A #GStaticRWLock must be initialized with this function before it
* can be used. Alternatively you can initialize it with
* #G_STATIC_RW_LOCK_INIT.
*
* Deprecated: 2.32: Use g_rw_lock_init() instead
*/
void
g_static_rw_lock_init (GStaticRWLock* lock)
{
static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
g_return_if_fail (lock);
*lock = init_lock;
}
inline static void
g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
{
if (!*cond)
*cond = g_cond_new ();
g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
}
inline static void
g_static_rw_lock_signal (GStaticRWLock* lock)
{
if (lock->want_to_write && lock->write_cond)
g_cond_signal (lock->write_cond);
else if (lock->want_to_read && lock->read_cond)
g_cond_broadcast (lock->read_cond);
}
/**
* g_static_rw_lock_reader_lock:
* @lock: a #GStaticRWLock to lock for reading.
*
* Locks @lock for reading. There may be unlimited concurrent locks for
* reading of a #GStaticRWLock at the same time. If @lock is already
* locked for writing by another thread or if another thread is already
* waiting to lock @lock for writing, this function will block until
* @lock is unlocked by the other writing thread and no other writing
* threads want to lock @lock. This lock has to be unlocked by
* g_static_rw_lock_reader_unlock().
*
* #GStaticRWLock is not recursive. It might seem to be possible to
* recursively lock for reading, but that can result in a deadlock, due
* to writer preference.
*
* Deprecated: 2.32: Use g_rw_lock_reader_lock() instead
*/
void
g_static_rw_lock_reader_lock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
if (!g_threads_got_initialized)
return;
g_static_mutex_lock (&lock->mutex);
lock->want_to_read++;
while (lock->have_writer || lock->want_to_write)
g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
lock->want_to_read--;
lock->read_counter++;
g_static_mutex_unlock (&lock->mutex);
}
/**
* g_static_rw_lock_reader_trylock:
* @lock: a #GStaticRWLock to lock for reading.
* @Returns: %TRUE, if @lock could be locked for reading.
*
* Tries to lock @lock for reading. If @lock is already locked for
* writing by another thread or if another thread is already waiting to
* lock @lock for writing, immediately returns %FALSE. Otherwise locks
* @lock for reading and returns %TRUE. This lock has to be unlocked by
* g_static_rw_lock_reader_unlock().
*
* Deprectated: 2.32: Use g_rw_lock_reader_trylock() instead
*/
gboolean
g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
{
gboolean ret_val = FALSE;
g_return_val_if_fail (lock, FALSE);
if (!g_threads_got_initialized)
return TRUE;
g_static_mutex_lock (&lock->mutex);
if (!lock->have_writer && !lock->want_to_write)
{
lock->read_counter++;
ret_val = TRUE;
}
g_static_mutex_unlock (&lock->mutex);
return ret_val;
}
/**
* g_static_rw_lock_reader_unlock:
* @lock: a #GStaticRWLock to unlock after reading.
*
* Unlocks @lock. If a thread waits to lock @lock for writing and all
* locks for reading have been unlocked, the waiting thread is woken up
* and can lock @lock for writing.
*
* Deprectated: 2.32: Use g_rw_lock_reader_unlock() instead
*/
void
g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
if (!g_threads_got_initialized)
return;
g_static_mutex_lock (&lock->mutex);
lock->read_counter--;
if (lock->read_counter == 0)
g_static_rw_lock_signal (lock);
g_static_mutex_unlock (&lock->mutex);
}
/**
* g_static_rw_lock_writer_lock:
* @lock: a #GStaticRWLock to lock for writing.
*
* Locks @lock for writing. If @lock is already locked for writing or
* reading by other threads, this function will block until @lock is
* completely unlocked and then lock @lock for writing. While this
* functions waits to lock @lock, no other thread can lock @lock for
* reading. When @lock is locked for writing, no other thread can lock
* @lock (neither for reading nor writing). This lock has to be
* unlocked by g_static_rw_lock_writer_unlock().
*
* Deprectated: 2.32: Use g_rw_lock_writer_lock() instead
*/
void
g_static_rw_lock_writer_lock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
if (!g_threads_got_initialized)
return;
g_static_mutex_lock (&lock->mutex);
lock->want_to_write++;
while (lock->have_writer || lock->read_counter)
g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
lock->want_to_write--;
lock->have_writer = TRUE;
g_static_mutex_unlock (&lock->mutex);
}
/**
* g_static_rw_lock_writer_trylock:
* @lock: a #GStaticRWLock to lock for writing.
* @Returns: %TRUE, if @lock could be locked for writing.
*
* Tries to lock @lock for writing. If @lock is already locked (for
* either reading or writing) by another thread, it immediately returns
* %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
* lock has to be unlocked by g_static_rw_lock_writer_unlock().
*
* Deprectated: 2.32: Use g_rw_lock_writer_trylock() instead
*/
gboolean
g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
{
gboolean ret_val = FALSE;
g_return_val_if_fail (lock, FALSE);
if (!g_threads_got_initialized)
return TRUE;
g_static_mutex_lock (&lock->mutex);
if (!lock->have_writer && !lock->read_counter)
{
lock->have_writer = TRUE;
ret_val = TRUE;
}
g_static_mutex_unlock (&lock->mutex);
return ret_val;
}
/**
* g_static_rw_lock_writer_unlock:
* @lock: a #GStaticRWLock to unlock after writing.
*
* Unlocks @lock. If a thread is waiting to lock @lock for writing and
* all locks for reading have been unlocked, the waiting thread is
* woken up and can lock @lock for writing. If no thread is waiting to
* lock @lock for writing, and some thread or threads are waiting to
* lock @lock for reading, the waiting threads are woken up and can
* lock @lock for reading.
*
* Deprectated: 2.32: Use g_rw_lock_writer_unlock() instead
*/
void
g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
{
g_return_if_fail (lock);
if (!g_threads_got_initialized)
return;
g_static_mutex_lock (&lock->mutex);
lock->have_writer = FALSE;
g_static_rw_lock_signal (lock);
g_static_mutex_unlock (&lock->mutex);
}
/**
* g_static_rw_lock_free:
* @lock: a #GStaticRWLock to be freed.
*
* Releases all resources allocated to @lock.
*
* You don't have to call this functions for a #GStaticRWLock with an
* unbounded lifetime, i.e. objects declared 'static', but if you have
* a #GStaticRWLock as a member of a structure, and the structure is
* freed, you should also free the #GStaticRWLock.
*
* Deprecated: 2.32: Use a #GRWLock instead
*/
void
g_static_rw_lock_free (GStaticRWLock* lock)
{
g_return_if_fail (lock);
if (lock->read_cond)
{
g_cond_free (lock->read_cond);
lock->read_cond = NULL;
}
if (lock->write_cond)
{
g_cond_free (lock->write_cond);
lock->write_cond = NULL;
}
g_static_mutex_free (&lock->mutex);
}
/* GPrivate {{{1 ------------------------------------------------------ */
/**
* g_private_new:
* @notify: a #GDestroyNotify
*
* Creates a new #GPrivate.
*
* Deprecated:2.32: dynamic allocation of #GPrivate is a bad idea. Use
* static storage and G_PRIVATE_INIT() instead.
*
* Returns: a newly allocated #GPrivate (which can never be destroyed)
*/
GPrivate *
g_private_new (GDestroyNotify notify)
{
GPrivate tmp = G_PRIVATE_INIT (notify);
GPrivate *key;
key = g_slice_new (GPrivate);
*key = tmp;
return key;
}
/* {{{1 GStaticPrivate */
typedef struct _GStaticPrivateNode GStaticPrivateNode;
struct _GStaticPrivateNode
{
gpointer data;
GDestroyNotify destroy;
GStaticPrivate *owner;
};
static void
g_static_private_cleanup (gpointer data)
{
GArray *array = data;
guint i;
for (i = 0; i < array->len; i++ )
{
GStaticPrivateNode *node = &g_array_index (array, GStaticPrivateNode, i);
if (node->destroy)
node->destroy (node->data);
}
g_array_free (array, TRUE);
}
GPrivate static_private_private = G_PRIVATE_INIT (g_static_private_cleanup);
/**
* GStaticPrivate:
*
* A #GStaticPrivate works almost like a #GPrivate, but it has one
* significant advantage. It doesn't need to be created at run-time
* like a #GPrivate, but can be defined at compile-time. This is
* similar to the difference between #GMutex and #GStaticMutex. Now
* look at our give_me_next_number() example with
* #GStaticPrivate:
*
*
* Using GStaticPrivate for per-thread data
*
* int
* give_me_next_number ()
* {
* static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
* int *current_number = g_static_private_get (¤t_number_key);
*
* if (!current_number)
* {
* current_number = g_new (int,1);
* *current_number = 0;
* g_static_private_set (¤t_number_key, current_number, g_free);
* }
*
* *current_number = calc_next_number (*current_number);
*
* return *current_number;
* }
*
*
*/
/**
* G_STATIC_PRIVATE_INIT:
*
* Every #GStaticPrivate must be initialized with this macro, before it
* can be used.
*
* |[
* GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
* ]|
*/
/**
* g_static_private_init:
* @private_key: a #GStaticPrivate to be initialized
*
* Initializes @private_key. Alternatively you can initialize it with
* #G_STATIC_PRIVATE_INIT.
*/
void
g_static_private_init (GStaticPrivate *private_key)
{
private_key->index = 0;
}
/**
* g_static_private_get:
* @private_key: a #GStaticPrivate
*
* Works like g_private_get() only for a #GStaticPrivate.
*
* This function works even if g_thread_init() has not yet been called.
*
* Returns: the corresponding pointer
*/
gpointer
g_static_private_get (GStaticPrivate *private_key)
{
GArray *array;
gpointer ret = NULL;
array = g_private_get (&static_private_private);
if (array && private_key->index != 0 && private_key->index <= array->len)
{
GStaticPrivateNode *node;
node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
/* Deal with the possibility that the GStaticPrivate which used
* to have this index got freed and the index got allocated to
* a new one. In this case, the data in the node is stale, so
* free it and return NULL.
*/
if (G_UNLIKELY (node->owner != private_key))
{
if (node->destroy)
node->destroy (node->data);
node->destroy = NULL;
node->data = NULL;
node->owner = NULL;
}
ret = node->data;
}
return ret;
}
/**
* g_static_private_set:
* @private_key: a #GStaticPrivate
* @data: the new pointer
* @notify: a function to be called with the pointer whenever the
* current thread ends or sets this pointer again
*
* Sets the pointer keyed to @private_key for the current thread and
* the function @notify to be called with that pointer (%NULL or
* non-%NULL), whenever the pointer is set again or whenever the
* current thread ends.
*
* This function works even if g_thread_init() has not yet been called.
* If g_thread_init() is called later, the @data keyed to @private_key
* will be inherited only by the main thread, i.e. the one that called
* g_thread_init().
*
* @notify is used quite differently from @destructor in
* g_private_new().
*/
void
g_static_private_set (GStaticPrivate *private_key,
gpointer data,
GDestroyNotify notify)
{
GArray *array;
static guint next_index = 0;
GStaticPrivateNode *node;
if (!private_key->index)
{
G_LOCK (g_thread);
if (!private_key->index)
{
if (g_thread_free_indices)
{
private_key->index = GPOINTER_TO_UINT (g_thread_free_indices->data);
g_thread_free_indices = g_slist_delete_link (g_thread_free_indices,
g_thread_free_indices);
}
else
private_key->index = ++next_index;
}
G_UNLOCK (g_thread);
}
array = g_private_get (&static_private_private);
if (!array)
{
array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
g_private_set (&static_private_private, array);
}
if (private_key->index > array->len)
g_array_set_size (array, private_key->index);
node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
if (node->destroy)
node->destroy (node->data);
node->data = data;
node->destroy = notify;
node->owner = private_key;
}
/**
* g_static_private_free:
* @private_key: a #GStaticPrivate to be freed
*
* Releases all resources allocated to @private_key.
*
* You don't have to call this functions for a #GStaticPrivate with an
* unbounded lifetime, i.e. objects declared 'static', but if you have
* a #GStaticPrivate as a member of a structure and the structure is
* freed, you should also free the #GStaticPrivate.
*/
void
g_static_private_free (GStaticPrivate *private_key)
{
guint idx = private_key->index;
if (!idx)
return;
private_key->index = 0;
/* Freeing the per-thread data is deferred to either the
* thread end or the next g_static_private_get() call for
* the same index.
*/
G_LOCK (g_thread);
g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
GUINT_TO_POINTER (idx));
G_UNLOCK (g_thread);
}
/* GMutex {{{1 ------------------------------------------------------ */
/**
* g_mutex_new:
*
* Allocates and initializes a new #GMutex.
*
* Returns: a newly allocated #GMutex. Use g_mutex_free() to free
*
* Deprecated:3.32:GMutex can now be statically allocated, or embedded
* in structures and initialised with g_mutex_init().
*/
GMutex *
g_mutex_new (void)
{
GMutex *mutex;
mutex = g_slice_new (GMutex);
g_mutex_init (mutex);
return mutex;
}
/**
* g_mutex_free:
* @mutex: a #GMutex
*
* Destroys a @mutex that has been created with g_mutex_new().
*
* Calling g_mutex_free() on a locked mutex may result
* in undefined behaviour.
*
* Deprecated:3.32:GMutex can now be statically allocated, or embedded
* in structures and initialised with g_mutex_init().
*/
void
g_mutex_free (GMutex *mutex)
{
g_mutex_clear (mutex);
g_slice_free (GMutex, mutex);
}
/* GCond {{{1 ------------------------------------------------------ */
/**
* g_cond_new:
*
* Allocates and initializes a new #GCond.
*
* Returns: a newly allocated #GCond. Free with g_cond_free()
*
* Deprecated:3.32:GCond can now be statically allocated, or embedded
* in structures and initialised with g_cond_init().
*/
GCond *
g_cond_new (void)
{
GCond *cond;
cond = g_slice_new (GCond);
g_cond_init (cond);
return cond;
}
/**
* g_cond_free:
* @cond: a #GCond
*
* Destroys a #GCond that has been created with g_cond_new().
*
* Calling g_cond_free() for a #GCond on which threads are
* blocking leads to undefined behaviour.
*
* Deprecated:3.32:GCond can now be statically allocated, or embedded
* in structures and initialised with g_cond_init().
*/
void
g_cond_free (GCond *cond)
{
g_cond_clear (cond);
g_slice_free (GCond, cond);
}
/**
* g_cond_timed_wait:
* @cond: a #GCond
* @mutex: a #GMutex that is currently locked
* @abs_time: a #GTimeVal, determining the final time
*
* Waits until this thread is woken up on @cond, but not longer than
* until the time specified by @abs_time. The @mutex is unlocked before
* falling asleep and locked again before resuming.
*
* If @abs_time is %NULL, g_cond_timed_wait() acts like g_cond_wait().
*
* This function can be used even if g_thread_init() has not yet been
* called, and, in that case, will immediately return %TRUE.
*
* To easily calculate @abs_time a combination of g_get_current_time()
* and g_time_val_add() can be used.
*
* Returns: %TRUE if @cond was signalled, or %FALSE on timeout
* Deprecated:2.32: Use g_cond_wait_until() instead.
*/
gboolean
g_cond_timed_wait (GCond *cond,
GMutex *mutex,
GTimeVal *abs_time)
{
gint64 end_time;
if (abs_time == NULL)
{
g_cond_wait (cond, mutex);
return TRUE;
}
end_time = abs_time->tv_sec;
end_time *= 1000000;
end_time += abs_time->tv_usec;
#ifdef CLOCK_MONOTONIC
/* would be nice if we had clock_rtoffset, but that didn't seem to
* make it into the kernel yet...
*/
end_time += g_get_monotonic_time () - g_get_real_time ();
#else
/* if CLOCK_MONOTONIC is not defined then g_get_montonic_time() and
* g_get_real_time() are returning the same clock, so don't bother...
*/
#endif
return g_cond_wait_until (cond, mutex, end_time);
}
/* {{{1 Epilogue */
/* vim: set foldmethod=marker: */