| /* 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. |
| */ |
| |
| /* Prelude {{{1 ----------------------------------------------------------- */ |
| |
| /* |
| * Modified by the GLib Team and others 1997-2000. See the AUTHORS |
| * file for a list of people on the GLib Team. See the ChangeLog |
| * files for a list of changes. These files are distributed with |
| * GLib at ftp://ftp.gtk.org/pub/gtk/. |
| */ |
| |
| /* |
| * MT safe |
| */ |
| |
| /* implement gthread.h's inline functions */ |
| #define G_IMPLEMENT_INLINES 1 |
| #define __G_THREAD_C__ |
| |
| #include "config.h" |
| |
| #include "gthread.h" |
| #include "gthreadprivate.h" |
| |
| #ifdef HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| |
| #ifndef G_OS_WIN32 |
| #include <sys/time.h> |
| #include <time.h> |
| #else |
| #include <windows.h> |
| #endif /* G_OS_WIN32 */ |
| |
| #include <string.h> |
| |
| #include "garray.h" |
| #include "gslist.h" |
| #include "gtestutils.h" |
| #include "gtimer.h" |
| |
| |
| /** |
| * SECTION:threads |
| * @title: Threads |
| * @short_description: thread abstraction; including threads, different |
| * mutexes, conditions and thread private data |
| * @see_also: #GThreadPool, #GAsyncQueue |
| * |
| * Threads act almost like processes, but unlike processes all threads |
| * of one process share the same memory. This is good, as it provides |
| * easy communication between the involved threads via this shared |
| * memory, and it is bad, because strange things (so called |
| * "Heisenbugs") might happen if the program is not carefully designed. |
| * In particular, due to the concurrent nature of threads, no |
| * assumptions on the order of execution of code running in different |
| * threads can be made, unless order is explicitly forced by the |
| * programmer through synchronization primitives. |
| * |
| * The aim of the thread related functions in GLib is to provide a |
| * portable means for writing multi-threaded software. There are |
| * primitives for mutexes to protect the access to portions of memory |
| * (#GMutex, #GStaticMutex, #G_LOCK_DEFINE, #GStaticRecMutex and |
| * #GStaticRWLock). There are primitives for condition variables to |
| * allow synchronization of threads (#GCond). There are primitives for |
| * thread-private data - data that every thread has a private instance |
| * of (#GPrivate, #GStaticPrivate). Last but definitely not least there |
| * are primitives to portably create and manage threads (#GThread). |
| * |
| * The threading system is initialized with g_thread_init(), which |
| * takes an optional custom thread implementation or %NULL for the |
| * default implementation. If you want to call g_thread_init() with a |
| * non-%NULL argument this must be done before executing any other GLib |
| * functions (except g_mem_set_vtable()). This is a requirement even if |
| * no threads are in fact ever created by the process. |
| * |
| * Calling g_thread_init() with a %NULL argument is somewhat more |
| * relaxed. You may call any other glib functions in the main thread |
| * before g_thread_init() as long as g_thread_init() is not called from |
| * a glib callback, or with any locks held. However, many libraries |
| * above glib does not support late initialization of threads, so doing |
| * this should be avoided if possible. |
| * |
| * Please note that since version 2.24 the GObject initialization |
| * function g_type_init() initializes threads (with a %NULL argument), |
| * so most applications, including those using Gtk+ will run with |
| * threads enabled. If you want a special thread implementation, make |
| * sure you call g_thread_init() before g_type_init() is called. |
| * |
| * After calling g_thread_init(), GLib is completely thread safe (all |
| * global data is automatically locked), but individual data structure |
| * instances are not automatically locked for performance reasons. So, |
| * for example you must coordinate accesses to the same #GHashTable |
| * from multiple threads. The two notable exceptions from this rule |
| * are #GMainLoop and #GAsyncQueue, which <emphasis>are</emphasis> |
| * threadsafe and need no further application-level locking to be |
| * accessed from multiple threads. |
| * |
| * To help debugging problems in multithreaded applications, GLib |
| * supports error-checking mutexes that will give you helpful error |
| * messages on common problems. To use error-checking mutexes, define |
| * the symbol #G_ERRORCHECK_MUTEXES when compiling the application. |
| **/ |
| |
| /** |
| * G_THREADS_IMPL_POSIX: |
| * |
| * This macro is defined if POSIX style threads are used. |
| **/ |
| |
| /** |
| * G_THREADS_ENABLED: |
| * |
| * This macro is defined if GLib was compiled with thread support. This |
| * does not necessarily mean that there is a thread implementation |
| * available, but it does mean that the infrastructure is in place and |
| * that once you provide a thread implementation to g_thread_init(), |
| * GLib will be multi-thread safe. If #G_THREADS_ENABLED is not |
| * defined, then Glib is not, and cannot be, multi-thread safe. |
| **/ |
| |
| /** |
| * G_THREADS_IMPL_NONE: |
| * |
| * This macro is defined if no thread implementation is used. You can, |
| * however, provide one to g_thread_init() to make GLib multi-thread |
| * safe. |
| **/ |
| |
| /* G_LOCK Documentation {{{1 ---------------------------------------------- */ |
| |
| /* IMPLEMENTATION NOTE: |
| * |
| * G_LOCK_DEFINE and friends are convenience macros defined in |
| * gthread.h. Their documentation lives here. |
| */ |
| |
| /** |
| * G_LOCK_DEFINE: |
| * @name: the name of the lock. |
| * |
| * The %G_LOCK_* macros provide a convenient interface to #GStaticMutex |
| * with the advantage that they will expand to nothing in programs |
| * compiled against a thread-disabled GLib, saving code and memory |
| * there. #G_LOCK_DEFINE defines a lock. It can appear anywhere |
| * variable definitions may appear in programs, i.e. in the first block |
| * of a function or outside of functions. The @name parameter will be |
| * mangled to get the name of the #GStaticMutex. This means that you |
| * can use names of existing variables as the parameter - e.g. the name |
| * of the variable you intent to protect with the lock. Look at our |
| * <function>give_me_next_number()</function> example using the |
| * %G_LOCK_* macros: |
| * |
| * <example> |
| * <title>Using the %G_LOCK_* convenience macros</title> |
| * <programlisting> |
| * G_LOCK_DEFINE (current_number); |
| * |
| * int |
| * give_me_next_number (void) |
| * { |
| * static int current_number = 0; |
| * int ret_val; |
| * |
| * G_LOCK (current_number); |
| * ret_val = current_number = calc_next_number (current_number); |
| * G_UNLOCK (current_number); |
| * |
| * return ret_val; |
| * } |
| * </programlisting> |
| * </example> |
| **/ |
| |
| /** |
| * G_LOCK_DEFINE_STATIC: |
| * @name: the name of the lock. |
| * |
| * This works like #G_LOCK_DEFINE, but it creates a static object. |
| **/ |
| |
| /** |
| * G_LOCK_EXTERN: |
| * @name: the name of the lock. |
| * |
| * This declares a lock, that is defined with #G_LOCK_DEFINE in another |
| * module. |
| **/ |
| |
| /** |
| * G_LOCK: |
| * @name: the name of the lock. |
| * |
| * Works like g_mutex_lock(), but for a lock defined with |
| * #G_LOCK_DEFINE. |
| **/ |
| |
| /** |
| * G_TRYLOCK: |
| * @name: the name of the lock. |
| * @Returns: %TRUE, if the lock could be locked. |
| * |
| * Works like g_mutex_trylock(), but for a lock defined with |
| * #G_LOCK_DEFINE. |
| **/ |
| |
| /** |
| * G_UNLOCK: |
| * @name: the name of the lock. |
| * |
| * Works like g_mutex_unlock(), but for a lock defined with |
| * #G_LOCK_DEFINE. |
| **/ |
| |
| /* GThreadError {{{1 ------------------------------------------------------- */ |
| /** |
| * GThreadError: |
| * @G_THREAD_ERROR_AGAIN: a thread couldn't be created due to resource |
| * shortage. Try again later. |
| * |
| * Possible errors of thread related functions. |
| **/ |
| |
| /** |
| * G_THREAD_ERROR: |
| * |
| * The error domain of the GLib thread subsystem. |
| **/ |
| GQuark |
| g_thread_error_quark (void) |
| { |
| return g_quark_from_static_string ("g_thread_error"); |
| } |
| |
| /* Miscellaneous Structures {{{1 ------------------------------------------ */ |
| /* Keep this in sync with GRealThread in gmain.c! */ |
| typedef struct _GRealThread GRealThread; |
| struct _GRealThread |
| { |
| GThread thread; |
| gpointer private_data; |
| GRealThread *next; |
| gpointer retval; |
| GSystemThread system_thread; |
| }; |
| |
| typedef struct _GStaticPrivateNode GStaticPrivateNode; |
| struct _GStaticPrivateNode |
| { |
| gpointer data; |
| GDestroyNotify destroy; |
| }; |
| |
| static void g_thread_cleanup (gpointer data); |
| static void g_thread_fail (void); |
| static guint64 gettime (void); |
| |
| guint64 (*g_thread_gettime) (void) = gettime; |
| |
| /* Global Variables {{{1 -------------------------------------------------- */ |
| |
| static GSystemThread zero_thread; /* This is initialized to all zero */ |
| gboolean g_thread_use_default_impl = TRUE; |
| |
| /** |
| * g_thread_supported: |
| * @Returns: %TRUE, if the thread system is initialized. |
| * |
| * This function returns %TRUE if the thread system is initialized, and |
| * %FALSE if it is not. |
| * |
| * <note><para>This function is actually a macro. Apart from taking the |
| * address of it you can however use it as if it was a |
| * function.</para></note> |
| **/ |
| |
| /* IMPLEMENTATION NOTE: |
| * |
| * g_thread_supported() is just returns g_threads_got_initialized |
| */ |
| gboolean g_threads_got_initialized = FALSE; |
| |
| |
| /* Thread Implementation Virtual Function Table {{{1 ---------------------- */ |
| /* Virtual Function Table Documentation {{{2 ------------------------------ */ |
| /** |
| * 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 used by g_thread_init() to initialize the |
| * thread system. The functions in the table are directly used by their |
| * g_* prepended counterparts (described in this document). For |
| * example, if you call g_mutex_new() then mutex_new() from the table |
| * provided to g_thread_init() will be called. |
| * |
| * <note><para>Do not use this struct unless you know what you are |
| * doing.</para></note> |
| **/ |
| |
| /* IMPLEMENTATION NOTE: |
| * |
| * g_thread_functions_for_glib_use is a global symbol that gets used by |
| * most of the "primative" threading calls. g_mutex_lock(), for |
| * example, is just a macro that calls the appropriate virtual function |
| * out of this table. |
| * |
| * For that reason, all of those macros are documented here. |
| */ |
| GThreadFunctions g_thread_functions_for_glib_use = { |
| /* GMutex Virtual Functions {{{2 ------------------------------------------ */ |
| |
| /** |
| * GMutex: |
| * |
| * The #GMutex struct is an opaque data structure to represent a mutex |
| * (mutual exclusion). It can be used to protect data against shared |
| * access. Take for example the following function: |
| * |
| * <example> |
| * <title>A function which will not work in a threaded environment</title> |
| * <programlisting> |
| * int |
| * give_me_next_number (void) |
| * { |
| * static int current_number = 0; |
| * |
| * /<!-- -->* now do a very complicated calculation to calculate the new |
| * * number, this might for example be a random number generator |
| * *<!-- -->/ |
| * current_number = calc_next_number (current_number); |
| * |
| * return current_number; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * It is easy to see that this won't work in a multi-threaded |
| * application. There current_number must be protected against shared |
| * access. A first naive implementation would be: |
| * |
| * <example> |
| * <title>The wrong way to write a thread-safe function</title> |
| * <programlisting> |
| * int |
| * give_me_next_number (void) |
| * { |
| * static int current_number = 0; |
| * int ret_val; |
| * static GMutex * mutex = NULL; |
| * |
| * if (!mutex) mutex = g_mutex_new (<!-- -->); |
| * |
| * g_mutex_lock (mutex); |
| * ret_val = current_number = calc_next_number (current_number); |
| * g_mutex_unlock (mutex); |
| * |
| * return ret_val; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * This looks like it would work, but there is a race condition while |
| * constructing the mutex and this code cannot work reliable. Please do |
| * not use such constructs in your own programs! One working solution |
| * is: |
| * |
| * <example> |
| * <title>A correct thread-safe function</title> |
| * <programlisting> |
| * static GMutex *give_me_next_number_mutex = NULL; |
| * |
| * /<!-- -->* this function must be called before any call to |
| * * give_me_next_number(<!-- -->) |
| * * |
| * * it must be called exactly once. |
| * *<!-- -->/ |
| * void |
| * init_give_me_next_number (void) |
| * { |
| * g_assert (give_me_next_number_mutex == NULL); |
| * give_me_next_number_mutex = g_mutex_new (<!-- -->); |
| * } |
| * |
| * int |
| * give_me_next_number (void) |
| * { |
| * static int current_number = 0; |
| * int ret_val; |
| * |
| * g_mutex_lock (give_me_next_number_mutex); |
| * ret_val = current_number = calc_next_number (current_number); |
| * g_mutex_unlock (give_me_next_number_mutex); |
| * |
| * return ret_val; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * #GStaticMutex provides a simpler and safer way of doing this. |
| * |
| * If you want to use a mutex, and your code should also work without |
| * calling g_thread_init() first, then you can not use a #GMutex, as |
| * g_mutex_new() requires that the thread system be initialized. Use a |
| * #GStaticMutex instead. |
| * |
| * A #GMutex should only be accessed via the following functions. |
| * |
| * <note><para>All of the <function>g_mutex_*</function> functions are |
| * actually macros. Apart from taking their addresses, you can however |
| * use them as if they were functions.</para></note> |
| **/ |
| |
| /** |
| * g_mutex_new: |
| * @Returns: a new #GMutex. |
| * |
| * Creates a new #GMutex. |
| * |
| * <note><para>This function will abort if g_thread_init() has not been |
| * called yet.</para></note> |
| **/ |
| (GMutex*(*)())g_thread_fail, |
| |
| /** |
| * g_mutex_lock: |
| * @mutex: a #GMutex. |
| * |
| * Locks @mutex. If @mutex is already locked by another thread, the |
| * current thread will block until @mutex is unlocked by the other |
| * thread. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will do nothing. |
| * |
| * <note><para>#GMutex is neither guaranteed to be recursive nor to be |
| * non-recursive, i.e. a thread could deadlock while calling |
| * g_mutex_lock(), if it already has locked @mutex. Use |
| * #GStaticRecMutex, if you need recursive mutexes.</para></note> |
| **/ |
| NULL, |
| |
| /** |
| * g_mutex_trylock: |
| * @mutex: a #GMutex. |
| * @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. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will immediately return %TRUE. |
| * |
| * <note><para>#GMutex is neither guaranteed to be recursive nor to be |
| * non-recursive, i.e. the return value of g_mutex_trylock() could be |
| * both %FALSE or %TRUE, if the current thread already has locked |
| * @mutex. Use #GStaticRecMutex, if you need recursive |
| * mutexes.</para></note> |
| **/ |
| NULL, |
| |
| /** |
| * g_mutex_unlock: |
| * @mutex: a #GMutex. |
| * |
| * Unlocks @mutex. If another thread is blocked in a g_mutex_lock() |
| * call for @mutex, it will be woken and can lock @mutex itself. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will do nothing. |
| **/ |
| NULL, |
| |
| /** |
| * g_mutex_free: |
| * @mutex: a #GMutex. |
| * |
| * Destroys @mutex. |
| * |
| * <note><para>Calling g_mutex_free() on a locked mutex may result in |
| * undefined behaviour.</para></note> |
| **/ |
| NULL, |
| |
| /* GCond Virtual Functions {{{2 ------------------------------------------ */ |
| |
| /** |
| * GCond: |
| * |
| * The #GCond struct is an opaque data structure that represents a |
| * condition. Threads can block on a #GCond if they find a certain |
| * condition to be false. If other threads change the state of this |
| * condition they signal the #GCond, and that causes the waiting |
| * threads to be woken up. |
| * |
| * <example> |
| * <title> |
| * Using GCond to block a thread until a condition is satisfied |
| * </title> |
| * <programlisting> |
| * GCond* data_cond = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/ |
| * GMutex* data_mutex = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/ |
| * gpointer current_data = NULL; |
| * |
| * void |
| * push_data (gpointer data) |
| * { |
| * g_mutex_lock (data_mutex); |
| * current_data = data; |
| * g_cond_signal (data_cond); |
| * g_mutex_unlock (data_mutex); |
| * } |
| * |
| * gpointer |
| * pop_data (void) |
| * { |
| * gpointer data; |
| * |
| * g_mutex_lock (data_mutex); |
| * while (!current_data) |
| * g_cond_wait (data_cond, data_mutex); |
| * data = current_data; |
| * current_data = NULL; |
| * g_mutex_unlock (data_mutex); |
| * |
| * return data; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * Whenever a thread calls <function>pop_data()</function> now, it will |
| * wait until current_data is non-%NULL, i.e. until some other thread |
| * has called <function>push_data()</function>. |
| * |
| * <note><para>It is important to use the g_cond_wait() and |
| * g_cond_timed_wait() functions only inside a loop which checks for the |
| * condition to be true. It is not guaranteed that the waiting thread |
| * will find the condition fulfilled after it wakes up, even if the |
| * signaling thread left the condition in that state: another thread may |
| * have altered the condition before the waiting thread got the chance |
| * to be woken up, even if the condition itself is protected by a |
| * #GMutex, like above.</para></note> |
| * |
| * A #GCond should only be accessed via the following functions. |
| * |
| * <note><para>All of the <function>g_cond_*</function> functions are |
| * actually macros. Apart from taking their addresses, you can however |
| * use them as if they were functions.</para></note> |
| **/ |
| |
| /** |
| * g_cond_new: |
| * @Returns: a new #GCond. |
| * |
| * Creates a new #GCond. This function will abort, if g_thread_init() |
| * has not been called yet. |
| **/ |
| (GCond*(*)())g_thread_fail, |
| |
| /** |
| * g_cond_signal: |
| * @cond: a #GCond. |
| * |
| * If threads are waiting for @cond, exactly one of them is woken up. |
| * It is good practice to hold the same lock as the waiting thread |
| * while calling this function, though not required. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will do nothing. |
| **/ |
| NULL, |
| |
| /** |
| * g_cond_broadcast: |
| * @cond: a #GCond. |
| * |
| * If threads are waiting for @cond, all of them are woken up. It is |
| * good practice to lock the same mutex as the waiting threads, while |
| * calling this function, though not required. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will do nothing. |
| **/ |
| NULL, |
| |
| /** |
| * g_cond_wait: |
| * @cond: a #GCond. |
| * @mutex: a #GMutex, that is currently locked. |
| * |
| * Waits until this thread is woken up on @cond. The @mutex is unlocked |
| * before falling asleep and locked again before resuming. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will immediately return. |
| **/ |
| NULL, |
| |
| /** |
| * g_cond_timed_wait: |
| * @cond: a #GCond. |
| * @mutex: a #GMutex that is currently locked. |
| * @abs_time: a #GTimeVal, determining the final time. |
| * @Returns: %TRUE if @cond was signalled, or %FALSE on timeout. |
| * |
| * 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. |
| **/ |
| NULL, |
| |
| /** |
| * g_cond_free: |
| * @cond: a #GCond. |
| * |
| * Destroys the #GCond. |
| **/ |
| NULL, |
| |
| /* GPrivate Virtual Functions {{{2 --------------------------------------- */ |
| |
| /** |
| * GPrivate: |
| * |
| * The #GPrivate struct is an opaque data structure to represent a |
| * thread private data key. Threads can thereby obtain and set a |
| * pointer which is private to the current thread. Take our |
| * <function>give_me_next_number(<!-- -->)</function> example from |
| * above. Suppose we don't want <literal>current_number</literal> to be |
| * shared between the threads, but instead to be private to each thread. |
| * This can be done as follows: |
| * |
| * <example> |
| * <title>Using GPrivate for per-thread data</title> |
| * <programlisting> |
| * GPrivate* current_number_key = NULL; /<!-- -->* Must be initialized somewhere |
| * with g_private_new (g_free); *<!-- -->/ |
| * |
| * int |
| * give_me_next_number (void) |
| * { |
| * int *current_number = g_private_get (current_number_key); |
| * |
| * if (!current_number) |
| * { |
| * current_number = g_new (int, 1); |
| * *current_number = 0; |
| * g_private_set (current_number_key, current_number); |
| * } |
| * |
| * *current_number = calc_next_number (*current_number); |
| * |
| * return *current_number; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * Here the pointer belonging to the key |
| * <literal>current_number_key</literal> is read. If it is %NULL, it has |
| * not been set yet. Then get memory for an integer value, assign this |
| * memory to the pointer and write the pointer back. Now we have an |
| * integer value that is private to the current thread. |
| * |
| * The #GPrivate struct should only be accessed via the following |
| * functions. |
| * |
| * <note><para>All of the <function>g_private_*</function> functions are |
| * actually macros. Apart from taking their addresses, you can however |
| * use them as if they were functions.</para></note> |
| **/ |
| |
| /** |
| * g_private_new: |
| * @destructor: a function to destroy the data keyed to #GPrivate when |
| * a thread ends. |
| * @Returns: a new #GPrivate. |
| * |
| * Creates a new #GPrivate. If @destructor is non-%NULL, it is a |
| * pointer to a destructor function. Whenever a thread ends and the |
| * corresponding pointer keyed to this instance of #GPrivate is |
| * non-%NULL, the destructor is called with this pointer as the |
| * argument. |
| * |
| * <note><para>@destructor is used quite differently from @notify in |
| * g_static_private_set().</para></note> |
| * |
| * <note><para>A #GPrivate can not be freed. Reuse it instead, if you |
| * can, to avoid shortage, or use #GStaticPrivate.</para></note> |
| * |
| * <note><para>This function will abort if g_thread_init() has not been |
| * called yet.</para></note> |
| **/ |
| (GPrivate*(*)(GDestroyNotify))g_thread_fail, |
| |
| /** |
| * g_private_get: |
| * @private_key: a #GPrivate. |
| * @Returns: the corresponding pointer. |
| * |
| * Returns the pointer keyed to @private_key for the current thread. If |
| * g_private_set() hasn't been called for the current @private_key and |
| * thread yet, this pointer will be %NULL. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will return the value of @private_key |
| * casted to #gpointer. Note however, that private data set |
| * <emphasis>before</emphasis> g_thread_init() will |
| * <emphasis>not</emphasis> be retained <emphasis>after</emphasis> the |
| * call. Instead, %NULL will be returned in all threads directly after |
| * g_thread_init(), regardless of any g_private_set() calls issued |
| * before threading system intialization. |
| **/ |
| NULL, |
| |
| /** |
| * g_private_set: |
| * @private_key: a #GPrivate. |
| * @data: the new pointer. |
| * |
| * Sets the pointer keyed to @private_key for the current thread. |
| * |
| * This function can be used even if g_thread_init() has not yet been |
| * called, and, in that case, will set @private_key to @data casted to |
| * #GPrivate*. See g_private_get() for resulting caveats. |
| **/ |
| NULL, |
| |
| /* GThread Virtual Functions {{{2 ---------------------------------------- */ |
| /** |
| * GThread: |
| * |
| * The #GThread struct represents a running thread. It has three public |
| * read-only members, but the underlying struct is bigger, so you must |
| * not copy this struct. |
| * |
| * <note><para>Resources for a joinable thread are not fully released |
| * until g_thread_join() is called for that thread.</para></note> |
| **/ |
| |
| /** |
| * GThreadFunc: |
| * @data: data passed to the thread. |
| * @Returns: the return value of the thread, which will be returned by |
| * g_thread_join(). |
| * |
| * Specifies the type of the @func functions passed to |
| * g_thread_create() or g_thread_create_full(). |
| **/ |
| |
| /** |
| * 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 |
| * |
| * Specifies the priority of a thread. |
| * |
| * <note><para>It is not guaranteed that threads with different priorities |
| * really behave accordingly. On some systems (e.g. Linux) there are no |
| * thread priorities. On other systems (e.g. Solaris) there doesn't |
| * seem to be different scheduling for different priorities. All in all |
| * try to avoid being dependent on priorities.</para></note> |
| **/ |
| |
| /** |
| * 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. |
| * @Returns: the new #GThread on success. |
| * |
| * This function creates a new thread with the default priority. |
| * |
| * If @joinable is %TRUE, you can wait for this threads termination |
| * calling g_thread_join(). Otherwise the thread will just disappear |
| * when it terminates. |
| * |
| * 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. |
| **/ |
| (void(*)(GThreadFunc, gpointer, gulong, |
| gboolean, gboolean, GThreadPriority, |
| gpointer, GError**))g_thread_fail, |
| |
| /** |
| * g_thread_yield: |
| * |
| * Gives way to other threads waiting to be scheduled. |
| * |
| * This function is often used as a method to make busy wait less evil. |
| * But in most cases you will encounter, there are better methods to do |
| * that. So in general you shouldn't use this function. |
| **/ |
| NULL, |
| |
| NULL, /* thread_join */ |
| NULL, /* thread_exit */ |
| NULL, /* thread_set_priority */ |
| NULL, /* thread_self */ |
| NULL /* thread_equal */ |
| }; |
| |
| /* Local Data {{{1 -------------------------------------------------------- */ |
| |
| static GMutex *g_once_mutex = NULL; |
| static GCond *g_once_cond = NULL; |
| static GPrivate *g_thread_specific_private = NULL; |
| static GRealThread *g_thread_all_threads = NULL; |
| static GSList *g_thread_free_indeces = NULL; |
| static GSList* g_once_init_list = NULL; |
| |
| G_LOCK_DEFINE_STATIC (g_thread); |
| |
| /* Initialisation {{{1 ---------------------------------------------------- */ |
| |
| #ifdef G_THREADS_ENABLED |
| /** |
| * g_thread_init: |
| * @vtable: a function table of type #GThreadFunctions, that provides |
| * the entry points to the thread system to be used. |
| * |
| * If you use GLib from more than one thread, you must initialize the |
| * thread system by calling g_thread_init(). Most of the time you will |
| * only have to call <literal>g_thread_init (NULL)</literal>. |
| * |
| * <note><para>Do not call g_thread_init() with a non-%NULL parameter unless |
| * you really know what you are doing.</para></note> |
| * |
| * <note><para>g_thread_init() must not be called directly or indirectly as a |
| * callback from GLib. Also no mutexes may be currently locked while |
| * calling g_thread_init().</para></note> |
| * |
| * <note><para>g_thread_init() changes the way in which #GTimer measures |
| * elapsed time. As a consequence, timers that are running while |
| * g_thread_init() is called may report unreliable times.</para></note> |
| * |
| * Calling g_thread_init() multiple times is allowed (since version |
| * 2.24), but nothing happens except for the first call. If the |
| * argument is non-%NULL on such a call a warning will be printed, but |
| * otherwise the argument is ignored. |
| * |
| * If no thread system is available and @vtable is %NULL or if not all |
| * elements of @vtable are non-%NULL, then g_thread_init() will abort. |
| * |
| * <note><para>To use g_thread_init() in your program, you have to link with |
| * the libraries that the command <command>pkg-config --libs |
| * gthread-2.0</command> 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.</para></note> |
| **/ |
| |
| /* This must be called only once, before any threads are created. |
| * It will only be called from g_thread_init() in -lgthread. |
| */ |
| void |
| g_thread_init_glib (void) |
| { |
| /* We let the main thread (the one that calls g_thread_init) inherit |
| * the static_private data set before calling g_thread_init |
| */ |
| GRealThread* main_thread = (GRealThread*) g_thread_self (); |
| |
| /* mutex and cond creation works without g_threads_got_initialized */ |
| g_once_mutex = g_mutex_new (); |
| g_once_cond = g_cond_new (); |
| |
| /* we may only create mutex and cond in here */ |
| _g_mem_thread_init_noprivate_nomessage (); |
| |
| /* setup the basic threading system */ |
| g_threads_got_initialized = TRUE; |
| g_thread_specific_private = g_private_new (g_thread_cleanup); |
| g_private_set (g_thread_specific_private, main_thread); |
| G_THREAD_UF (thread_self, (&main_thread->system_thread)); |
| |
| /* complete memory system initialization, g_private_*() works now */ |
| _g_slice_thread_init_nomessage (); |
| |
| /* accomplish log system initialization to enable messaging */ |
| _g_messages_thread_init_nomessage (); |
| |
| /* we may run full-fledged initializers from here */ |
| _g_atomic_thread_init (); |
| _g_convert_thread_init (); |
| _g_rand_thread_init (); |
| _g_main_thread_init (); |
| _g_utils_thread_init (); |
| _g_futex_thread_init (); |
| #ifdef G_OS_WIN32 |
| _g_win32_thread_init (); |
| #endif |
| } |
| #endif /* G_THREADS_ENABLED */ |
| |
| /* The following sections implement: GOnce, GStaticMutex, GStaticRecMutex, |
| * GStaticPrivate, |
| **/ |
| |
| /* GOnce {{{1 ------------------------------------------------------------- */ |
| |
| /** |
| * GOnce: |
| * @status: the status of the #GOnce |
| * @retval: the value returned by the call to the function, if @status |
| * is %G_ONCE_STATUS_READY |
| * |
| * A #GOnce struct controls a one-time initialization function. Any |
| * one-time initialization function must have its own unique #GOnce |
| * struct. |
| * |
| * Since: 2.4 |
| **/ |
| |
| /** |
| * G_ONCE_INIT: |
| * |
| * A #GOnce must be initialized with this macro before it can be used. |
| * |
| * <informalexample> |
| * <programlisting> |
| * GOnce my_once = G_ONCE_INIT; |
| * </programlisting> |
| * </informalexample> |
| * |
| * Since: 2.4 |
| **/ |
| |
| /** |
| * GOnceStatus: |
| * @G_ONCE_STATUS_NOTCALLED: the function has not been called yet. |
| * @G_ONCE_STATUS_PROGRESS: the function call is currently in progress. |
| * @G_ONCE_STATUS_READY: the function has been called. |
| * |
| * The possible statuses of a one-time initialization function |
| * controlled by a #GOnce struct. |
| * |
| * Since: 2.4 |
| **/ |
| |
| /** |
| * g_once: |
| * @once: a #GOnce structure |
| * @func: the #GThreadFunc function associated to @once. This function |
| * is called only once, regardless of the number of times it and |
| * its associated #GOnce struct are passed to g_once(). |
| * @arg: data to be passed to @func |
| * |
| * The first call to this routine by a process with a given #GOnce |
| * struct calls @func with the given argument. Thereafter, subsequent |
| * calls to g_once() with the same #GOnce struct do not call @func |
| * again, but return the stored result of the first call. On return |
| * from g_once(), the status of @once will be %G_ONCE_STATUS_READY. |
| * |
| * For example, a mutex or a thread-specific data key must be created |
| * exactly once. In a threaded environment, calling g_once() ensures |
| * that the initialization is serialized across multiple threads. |
| * |
| * <note><para>Calling g_once() recursively on the same #GOnce struct in |
| * @func will lead to a deadlock.</para></note> |
| * |
| * <informalexample> |
| * <programlisting> |
| * gpointer |
| * get_debug_flags (void) |
| * { |
| * static GOnce my_once = G_ONCE_INIT; |
| * |
| * g_once (&my_once, parse_debug_flags, NULL); |
| * |
| * return my_once.retval; |
| * } |
| * </programlisting> |
| * </informalexample> |
| * |
| * Since: 2.4 |
| **/ |
| gpointer |
| g_once_impl (GOnce *once, |
| GThreadFunc func, |
| gpointer arg) |
| { |
| g_mutex_lock (g_once_mutex); |
| |
| while (once->status == G_ONCE_STATUS_PROGRESS) |
| g_cond_wait (g_once_cond, g_once_mutex); |
| |
| if (once->status != G_ONCE_STATUS_READY) |
| { |
| once->status = G_ONCE_STATUS_PROGRESS; |
| g_mutex_unlock (g_once_mutex); |
| |
| once->retval = func (arg); |
| |
| g_mutex_lock (g_once_mutex); |
| once->status = G_ONCE_STATUS_READY; |
| g_cond_broadcast (g_once_cond); |
| } |
| |
| g_mutex_unlock (g_once_mutex); |
| |
| return once->retval; |
| } |
| |
| /** |
| * g_once_init_enter: |
| * @value_location: location of a static initializable variable |
| * containing 0. |
| * @Returns: %TRUE if the initialization section should be entered, |
| * %FALSE and blocks otherwise |
| * |
| * Function to be called when starting a critical initialization |
| * section. The argument @value_location must point to a static |
| * 0-initialized variable that will be set to a value other than 0 at |
| * the end of the initialization section. In combination with |
| * g_once_init_leave() and the unique address @value_location, it can |
| * be ensured that an initialization section will be executed only once |
| * during a program's life time, and that concurrent threads are |
| * blocked until initialization completed. To be used in constructs |
| * like this: |
| * |
| * <informalexample> |
| * <programlisting> |
| * static gsize initialization_value = 0; |
| * |
| * if (g_once_init_enter (&initialization_value)) |
| * { |
| * gsize setup_value = 42; /<!-- -->* initialization code here *<!-- -->/ |
| * |
| * g_once_init_leave (&initialization_value, setup_value); |
| * } |
| * |
| * /<!-- -->* use initialization_value here *<!-- -->/ |
| * </programlisting> |
| * </informalexample> |
| * |
| * Since: 2.14 |
| **/ |
| gboolean |
| g_once_init_enter_impl (volatile gsize *value_location) |
| { |
| gboolean need_init = FALSE; |
| g_mutex_lock (g_once_mutex); |
| if (g_atomic_pointer_get (value_location) == NULL) |
| { |
| if (!g_slist_find (g_once_init_list, (void*) value_location)) |
| { |
| need_init = TRUE; |
| g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location); |
| } |
| else |
| do |
| g_cond_wait (g_once_cond, g_once_mutex); |
| while (g_slist_find (g_once_init_list, (void*) value_location)); |
| } |
| g_mutex_unlock (g_once_mutex); |
| return need_init; |
| } |
| |
| /** |
| * g_once_init_leave: |
| * @value_location: location of a static initializable variable |
| * containing 0. |
| * @initialization_value: new non-0 value for *@value_location. |
| * |
| * Counterpart to g_once_init_enter(). Expects a location of a static |
| * 0-initialized initialization variable, and an initialization value |
| * other than 0. Sets the variable to the initialization value, and |
| * releases concurrent threads blocking in g_once_init_enter() on this |
| * initialization variable. |
| * |
| * Since: 2.14 |
| **/ |
| void |
| g_once_init_leave (volatile gsize *value_location, |
| gsize initialization_value) |
| { |
| g_return_if_fail (g_atomic_pointer_get (value_location) == NULL); |
| g_return_if_fail (initialization_value != 0); |
| g_return_if_fail (g_once_init_list != NULL); |
| |
| g_atomic_pointer_set ((void**)value_location, (void*) initialization_value); |
| g_mutex_lock (g_once_mutex); |
| g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location); |
| g_cond_broadcast (g_once_cond); |
| g_mutex_unlock (g_once_mutex); |
| } |
| |
| /* GStaticMutex {{{1 ------------------------------------------------------ */ |
| |
| /** |
| * GStaticMutex: |
| * |
| * A #GStaticMutex works like a #GMutex, but it has one significant |
| * advantage. It doesn't need to be created at run-time like a #GMutex, |
| * but can be defined at compile-time. Here is a shorter, easier and |
| * safer version of our <function>give_me_next_number()</function> |
| * example: |
| * |
| * <example> |
| * <title> |
| * Using <structname>GStaticMutex</structname> |
| * to simplify thread-safe programming |
| * </title> |
| * <programlisting> |
| * 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; |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * 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 <function>g_static_mutex_*</function> functions apart |
| * from <function>g_static_mutex_get_mutex</function> can also be used |
| * even if g_thread_init() has not yet been called. Then they do |
| * nothing, apart from <function>g_static_mutex_trylock</function>, |
| * which does nothing but returning %TRUE. |
| * |
| * <note><para>All of the <function>g_static_mutex_*</function> |
| * functions are actually macros. Apart from taking their addresses, you |
| * can however use them as if they were functions.</para></note> |
| **/ |
| |
| /** |
| * 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(). |
| * |
| * <informalexample> |
| * <programlisting> |
| * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT; |
| * </programlisting> |
| * </informalexample> |
| **/ |
| |
| /** |
| * g_static_mutex_init: |
| * @mutex: a #GStaticMutex to be initialized. |
| * |
| * Initializes @mutex. Alternatively you can initialize it with |
| * #G_STATIC_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 sturcture 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. |
| **/ |
| GMutex * |
| g_static_mutex_get_mutex_impl (GMutex** mutex) |
| { |
| if (!g_thread_supported ()) |
| return NULL; |
| |
| g_assert (g_once_mutex); |
| |
| g_mutex_lock (g_once_mutex); |
| |
| if (!(*mutex)) |
| g_atomic_pointer_set (mutex, g_mutex_new()); |
| |
| g_mutex_unlock (g_once_mutex); |
| |
| return *mutex; |
| } |
| |
| /* 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. |
| **/ |
| |
| /** |
| * g_static_mutex_trylock: |
| * @mutex: a #GStaticMutex. |
| * @Returns: %TRUE, if the #GStaticMutex could be locked. |
| * |
| * Works like g_mutex_trylock(), but for a #GStaticMutex. |
| **/ |
| |
| /** |
| * g_static_mutex_unlock: |
| * @mutex: a #GStaticMutex. |
| * |
| * Works like g_mutex_unlock(), but for a #GStaticMutex. |
| **/ |
| |
| /** |
| * 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. |
| * |
| * <note><para>Calling g_static_mutex_free() on a locked mutex may |
| * result in undefined behaviour.</para></note> |
| **/ |
| 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; |
| } |
| |
| /* ------------------------------------------------------------------------ */ |
| |
| /** |
| * 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(). |
| * |
| * Even though #GStaticRecMutex is not opaque, it should only be used |
| * with the following functions. |
| * |
| * All of the <function>g_static_rec_mutex_*</function> functions can |
| * be used even if g_thread_init() has not been called. Then they do |
| * nothing, apart from <function>g_static_rec_mutex_trylock</function>, |
| * 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(). |
| * |
| * <informalexample> |
| * <programlisting> |
| * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT; |
| * </programlisting> |
| </informalexample> |
| **/ |
| |
| /** |
| * 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. |
| **/ |
| 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; |
| } |
| |
| /** |
| * 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. |
| **/ |
| void |
| g_static_rec_mutex_lock (GStaticRecMutex* mutex) |
| { |
| GSystemThread self; |
| |
| g_return_if_fail (mutex); |
| |
| if (!g_thread_supported ()) |
| return; |
| |
| G_THREAD_UF (thread_self, (&self)); |
| |
| if (g_system_thread_equal (self, mutex->owner)) |
| { |
| mutex->depth++; |
| return; |
| } |
| g_static_mutex_lock (&mutex->mutex); |
| g_system_thread_assign (mutex->owner, self); |
| mutex->depth = 1; |
| } |
| |
| /** |
| * 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. |
| **/ |
| gboolean |
| g_static_rec_mutex_trylock (GStaticRecMutex* mutex) |
| { |
| GSystemThread self; |
| |
| g_return_val_if_fail (mutex, FALSE); |
| |
| if (!g_thread_supported ()) |
| return TRUE; |
| |
| G_THREAD_UF (thread_self, (&self)); |
| |
| if (g_system_thread_equal (self, mutex->owner)) |
| { |
| mutex->depth++; |
| return TRUE; |
| } |
| |
| if (!g_static_mutex_trylock (&mutex->mutex)) |
| return FALSE; |
| |
| g_system_thread_assign (mutex->owner, self); |
| mutex->depth = 1; |
| return TRUE; |
| } |
| |
| /** |
| * 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. |
| **/ |
| void |
| g_static_rec_mutex_unlock (GStaticRecMutex* mutex) |
| { |
| g_return_if_fail (mutex); |
| |
| if (!g_thread_supported ()) |
| return; |
| |
| if (mutex->depth > 1) |
| { |
| mutex->depth--; |
| return; |
| } |
| g_system_thread_assign (mutex->owner, zero_thread); |
| g_static_mutex_unlock (&mutex->mutex); |
| } |
| |
| /** |
| * 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. |
| **/ |
| void |
| g_static_rec_mutex_lock_full (GStaticRecMutex *mutex, |
| guint depth) |
| { |
| GSystemThread self; |
| g_return_if_fail (mutex); |
| |
| if (!g_thread_supported ()) |
| return; |
| |
| if (depth == 0) |
| return; |
| |
| G_THREAD_UF (thread_self, (&self)); |
| |
| if (g_system_thread_equal (self, mutex->owner)) |
| { |
| mutex->depth += depth; |
| return; |
| } |
| g_static_mutex_lock (&mutex->mutex); |
| g_system_thread_assign (mutex->owner, self); |
| mutex->depth = 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. |
| **/ |
| guint |
| g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex) |
| { |
| guint depth; |
| |
| g_return_val_if_fail (mutex, 0); |
| |
| if (!g_thread_supported ()) |
| return 1; |
| |
| depth = mutex->depth; |
| |
| g_system_thread_assign (mutex->owner, zero_thread); |
| mutex->depth = 0; |
| g_static_mutex_unlock (&mutex->mutex); |
| |
| 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. |
| **/ |
| void |
| g_static_rec_mutex_free (GStaticRecMutex *mutex) |
| { |
| g_return_if_fail (mutex); |
| |
| g_static_mutex_free (&mutex->mutex); |
| } |
| |
| /* GStaticPrivate {{{1 ---------------------------------------------------- */ |
| |
| /** |
| * 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 <function>give_me_next_number()</function> example with |
| * #GStaticPrivate: |
| * |
| * <example> |
| * <title>Using GStaticPrivate for per-thread data</title> |
| * <programlisting> |
| * int |
| * give_me_next_number (<!-- -->) |
| * { |
| * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT; |
| * int *current_number = g_static_private_get (&current_number_key); |
| * |
| * if (!current_number) |
| * { |
| * current_number = g_new (int,1); |
| * *current_number = 0; |
| * g_static_private_set (&current_number_key, current_number, g_free); |
| * } |
| * |
| * *current_number = calc_next_number (*current_number); |
| * |
| * return *current_number; |
| * } |
| * </programlisting> |
| * </example> |
| **/ |
| |
| /** |
| * G_STATIC_PRIVATE_INIT: |
| * |
| * Every #GStaticPrivate must be initialized with this macro, before it |
| * can be used. |
| * |
| * <informalexample> |
| * <programlisting> |
| * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT; |
| * </programlisting> |
| * </informalexample> |
| **/ |
| |
| /** |
| * 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. |
| * @Returns: the corresponding pointer. |
| * |
| * Works like g_private_get() only for a #GStaticPrivate. |
| * |
| * This function works even if g_thread_init() has not yet been called. |
| **/ |
| gpointer |
| g_static_private_get (GStaticPrivate *private_key) |
| { |
| GRealThread *self = (GRealThread*) g_thread_self (); |
| GArray *array; |
| |
| array = self->private_data; |
| if (!array) |
| return NULL; |
| |
| if (!private_key->index) |
| return NULL; |
| else if (private_key->index <= array->len) |
| return g_array_index (array, GStaticPrivateNode, |
| private_key->index - 1).data; |
| else |
| return NULL; |
| } |
| |
| /** |
| * 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(). |
| * |
| * <note><para>@notify is used quite differently from @destructor in |
| * g_private_new().</para></note> |
| **/ |
| void |
| g_static_private_set (GStaticPrivate *private_key, |
| gpointer data, |
| GDestroyNotify notify) |
| { |
| GRealThread *self = (GRealThread*) g_thread_self (); |
| GArray *array; |
| static guint next_index = 0; |
| GStaticPrivateNode *node; |
| |
| array = self->private_data; |
| if (!array) |
| { |
| array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode)); |
| self->private_data = array; |
| } |
| |
| if (!private_key->index) |
| { |
| G_LOCK (g_thread); |
| |
| if (!private_key->index) |
| { |
| if (g_thread_free_indeces) |
| { |
| private_key->index = |
| GPOINTER_TO_UINT (g_thread_free_indeces->data); |
| g_thread_free_indeces = |
| g_slist_delete_link (g_thread_free_indeces, |
| g_thread_free_indeces); |
| } |
| else |
| private_key->index = ++next_index; |
| } |
| |
| G_UNLOCK (g_thread); |
| } |
| |
| 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) |
| { |
| gpointer ddata = node->data; |
| GDestroyNotify ddestroy = node->destroy; |
| |
| node->data = data; |
| node->destroy = notify; |
| |
| ddestroy (ddata); |
| } |
| else |
| { |
| node->data = data; |
| node->destroy = notify; |
| } |
| } |
| |
| /** |
| * 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; |
| GRealThread *thread; |
| |
| if (!idx) |
| return; |
| |
| private_key->index = 0; |
| |
| G_LOCK (g_thread); |
| |
| thread = g_thread_all_threads; |
| while (thread) |
| { |
| GArray *array = thread->private_data; |
| thread = thread->next; |
| |
| if (array && idx <= array->len) |
| { |
| GStaticPrivateNode *node = &g_array_index (array, |
| GStaticPrivateNode, |
| idx - 1); |
| gpointer ddata = node->data; |
| GDestroyNotify ddestroy = node->destroy; |
| |
| node->data = NULL; |
| node->destroy = NULL; |
| |
| if (ddestroy) |
| { |
| G_UNLOCK (g_thread); |
| ddestroy (ddata); |
| G_LOCK (g_thread); |
| } |
| } |
| } |
| g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces, |
| GUINT_TO_POINTER (idx)); |
| G_UNLOCK (g_thread); |
| } |
| |
| /* GThread Extra Functions {{{1 ------------------------------------------- */ |
| static void |
| g_thread_cleanup (gpointer data) |
| { |
| if (data) |
| { |
| GRealThread* thread = data; |
| if (thread->private_data) |
| { |
| GArray* array = thread->private_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); |
| } |
| |
| /* We only free the thread structure, if it isn't joinable. If |
| it is, the structure is freed in g_thread_join */ |
| if (!thread->thread.joinable) |
| { |
| GRealThread *t, *p; |
| |
| G_LOCK (g_thread); |
| for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next) |
| { |
| if (t == thread) |
| { |
| if (p) |
| p->next = t->next; |
| else |
| g_thread_all_threads = t->next; |
| break; |
| } |
| } |
| G_UNLOCK (g_thread); |
| |
| /* Just to make sure, this isn't used any more */ |
| g_system_thread_assign (thread->system_thread, zero_thread); |
| g_free (thread); |
| } |
| } |
| } |
| |
| static void |
| g_thread_fail (void) |
| { |
| g_error ("The thread system is not yet initialized."); |
| } |
| |
| #define G_NSEC_PER_SEC 1000000000 |
| |
| static guint64 |
| gettime (void) |
| { |
| #ifdef G_OS_WIN32 |
| guint64 v; |
| |
| /* Returns 100s of nanoseconds since start of 1601 */ |
| GetSystemTimeAsFileTime ((FILETIME *)&v); |
| |
| /* Offset to Unix epoch */ |
| v -= G_GINT64_CONSTANT (116444736000000000); |
| /* Convert to nanoseconds */ |
| v *= 100; |
| |
| return v; |
| #else |
| struct timeval tv; |
| |
| gettimeofday (&tv, NULL); |
| |
| return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC); |
| #endif |
| } |
| |
| static gpointer |
| g_thread_create_proxy (gpointer data) |
| { |
| GRealThread* thread = data; |
| |
| g_assert (data); |
| |
| /* This has to happen before G_LOCK, as that might call g_thread_self */ |
| g_private_set (g_thread_specific_private, data); |
| |
| /* the lock makes sure, that thread->system_thread is written, |
| before thread->thread.func is called. See g_thread_create. */ |
| G_LOCK (g_thread); |
| G_UNLOCK (g_thread); |
| |
| thread->retval = thread->thread.func (thread->thread.data); |
| |
| return NULL; |
| } |
| |
| /** |
| * 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: should this thread be bound to a system thread? |
| * @priority: a priority for the thread. |
| * @error: return location for error. |
| * @Returns: the new #GThread on success. |
| * |
| * This function creates a new thread with the priority @priority. If |
| * the underlying thread implementation supports it, the thread gets a |
| * stack size of @stack_size or the default value for the current |
| * platform, if @stack_size is 0. |
| * |
| * If @joinable is %TRUE, you can wait for this threads termination |
| * calling g_thread_join(). Otherwise the thread will just disappear |
| * when it terminates. If @bound is %TRUE, this thread will be |
| * scheduled in the system scope, otherwise the implementation is free |
| * to do scheduling in the process scope. The first variant is more |
| * expensive resource-wise, but generally faster. On some systems (e.g. |
| * Linux) all threads are bound. |
| * |
| * 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. |
| * |
| * <note><para>It is not guaranteed that threads with different priorities |
| * really behave accordingly. On some systems (e.g. Linux) there are no |
| * thread priorities. On other systems (e.g. Solaris) there doesn't |
| * seem to be different scheduling for different priorities. All in all |
| * try to avoid being dependent on priorities. Use |
| * %G_THREAD_PRIORITY_NORMAL here as a default.</para></note> |
| * |
| * <note><para>Only use g_thread_create_full() if you really can't use |
| * g_thread_create() instead. g_thread_create() does not take |
| * @stack_size, @bound, and @priority as arguments, as they should only |
| * be used in cases in which it is unavoidable.</para></note> |
| **/ |
| GThread* |
| g_thread_create_full (GThreadFunc func, |
| gpointer data, |
| gulong stack_size, |
| gboolean joinable, |
| gboolean bound, |
| GThreadPriority priority, |
| GError **error) |
| { |
| GRealThread* result; |
| GError *local_error = NULL; |
| g_return_val_if_fail (func, NULL); |
| g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL); |
| g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL); |
| |
| result = g_new0 (GRealThread, 1); |
| |
| result->thread.joinable = joinable; |
| result->thread.priority = priority; |
| result->thread.func = func; |
| result->thread.data = data; |
| result->private_data = NULL; |
| G_LOCK (g_thread); |
| G_THREAD_UF (thread_create, (g_thread_create_proxy, result, |
| stack_size, joinable, bound, priority, |
| &result->system_thread, &local_error)); |
| if (!local_error) |
| { |
| result->next = g_thread_all_threads; |
| g_thread_all_threads = result; |
| } |
| G_UNLOCK (g_thread); |
| |
| if (local_error) |
| { |
| g_propagate_error (error, local_error); |
| g_free (result); |
| return NULL; |
| } |
| |
| return (GThread*) result; |
| } |
| |
| /** |
| * g_thread_exit: |
| * @retval: the return value of this thread. |
| * |
| * Exits the current thread. If another thread is waiting for that |
| * thread using g_thread_join() and the current thread is joinable, the |
| * waiting thread will be woken up and get @retval as the return value |
| * of g_thread_join(). If the current thread is not joinable, @retval |
| * is ignored. Calling |
| * |
| * <informalexample> |
| * <programlisting> |
| * g_thread_exit (retval); |
| * </programlisting> |
| * </informalexample> |
| * |
| * is equivalent to returning @retval from the function @func, as given |
| * to g_thread_create(). |
| * |
| * <note><para>Never call g_thread_exit() from within a thread of a |
| * #GThreadPool, as that will mess up the bookkeeping and lead to funny |
| * and unwanted results.</para></note> |
| **/ |
| void |
| g_thread_exit (gpointer retval) |
| { |
| GRealThread* real = (GRealThread*) g_thread_self (); |
| real->retval = retval; |
| G_THREAD_CF (thread_exit, (void)0, ()); |
| } |
| |
| /** |
| * g_thread_join: |
| * @thread: a #GThread to be waited for. |
| * @Returns: the return value of the thread. |
| * |
| * Waits until @thread finishes, i.e. the function @func, as given to |
| * g_thread_create(), returns or g_thread_exit() is called by @thread. |
| * All resources of @thread including the #GThread struct are released. |
| * @thread must have been created with @joinable=%TRUE in |
| * g_thread_create(). The value returned by @func or given to |
| * g_thread_exit() by @thread is returned by this function. |
| **/ |
| gpointer |
| g_thread_join (GThread* thread) |
| { |
| GRealThread* real = (GRealThread*) thread; |
| GRealThread *p, *t; |
| gpointer retval; |
| |
| g_return_val_if_fail (thread, NULL); |
| g_return_val_if_fail (thread->joinable, NULL); |
| g_return_val_if_fail (!g_system_thread_equal (real->system_thread, |
| zero_thread), NULL); |
| |
| G_THREAD_UF (thread_join, (&real->system_thread)); |
| |
| retval = real->retval; |
| |
| G_LOCK (g_thread); |
| for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next) |
| { |
| if (t == (GRealThread*) thread) |
| { |
| if (p) |
| p->next = t->next; |
| else |
| g_thread_all_threads = t->next; |
| break; |
| } |
| } |
| G_UNLOCK (g_thread); |
| |
| /* Just to make sure, this isn't used any more */ |
| thread->joinable = 0; |
| g_system_thread_assign (real->system_thread, zero_thread); |
| |
| /* the thread structure for non-joinable threads is freed upon |
| thread end. We free the memory here. This will leave a loose end, |
| if a joinable thread is not joined. */ |
| |
| g_free (thread); |
| |
| return retval; |
| } |
| |
| /** |
| * g_thread_set_priority: |
| * @thread: a #GThread. |
| * @priority: a new priority for @thread. |
| * |
| * Changes the priority of @thread to @priority. |
| * |
| * <note><para>It is not guaranteed that threads with different |
| * priorities really behave accordingly. On some systems (e.g. Linux) |
| * there are no thread priorities. On other systems (e.g. Solaris) there |
| * doesn't seem to be different scheduling for different priorities. All |
| * in all try to avoid being dependent on priorities.</para></note> |
| **/ |
| void |
| g_thread_set_priority (GThread* thread, |
| GThreadPriority priority) |
| { |
| GRealThread* real = (GRealThread*) thread; |
| |
| g_return_if_fail (thread); |
| g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread)); |
| g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW); |
| g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT); |
| |
| thread->priority = priority; |
| |
| G_THREAD_CF (thread_set_priority, (void)0, |
| (&real->system_thread, priority)); |
| } |
| |
| /** |
| * g_thread_self: |
| * @Returns: the current thread. |
| * |
| * This functions returns the #GThread corresponding to the calling |
| * thread. |
| **/ |
| GThread* |
| g_thread_self (void) |
| { |
| GRealThread* thread = g_private_get (g_thread_specific_private); |
| |
| if (!thread) |
| { |
| /* If no thread data is available, provide and set one. This |
| can happen for the main thread and for threads, that are not |
| created by GLib. */ |
| thread = g_new0 (GRealThread, 1); |
| thread->thread.joinable = FALSE; /* This is a save guess */ |
| thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is |
| just a guess */ |
| thread->thread.func = NULL; |
| thread->thread.data = NULL; |
| thread->private_data = NULL; |
| |
| if (g_thread_supported ()) |
| G_THREAD_UF (thread_self, (&thread->system_thread)); |
| |
| g_private_set (g_thread_specific_private, thread); |
| |
| G_LOCK (g_thread); |
| thread->next = g_thread_all_threads; |
| g_thread_all_threads = thread; |
| G_UNLOCK (g_thread); |
| } |
| |
| return (GThread*)thread; |
| } |
| |
| /* 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: |
| * |
| * <example> |
| * <title>An array with access functions</title> |
| * <programlisting> |
| * 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); |
| * } |
| * </programlisting> |
| * </example> |
| * |
| * This example shows an array which can be accessed by many readers |
| * (the <function>my_array_get()</function> function) simultaneously, |
| * whereas the writers (the <function>my_array_set()</function> |
| * 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 <function>g_static_rw_lock_*</function> functions can be |
| * used even if g_thread_init() has not been called. Then they do |
| * nothing, apart from <function>g_static_rw_lock_*_trylock</function>, |
| * which does nothing but returning %TRUE. |
| * |
| * <note><para>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.</para></note> |
| **/ |
| |
| /** |
| * 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(). |
| * |
| * <informalexample> |
| * <programlisting> |
| * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT; |
| * </programlisting> |
| * </informalexample> |
| **/ |
| |
| /** |
| * 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. |
| **/ |
| 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. |
| **/ |
| 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(). |
| **/ |
| 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. |
| **/ |
| 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(). |
| **/ |
| 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(). |
| **/ |
| 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. |
| **/ |
| 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. |
| **/ |
| 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); |
| } |
| |
| /* Unsorted {{{1 ---------------------------------------------------------- */ |
| |
| /** |
| * g_thread_foreach |
| * @thread_func: function to call for all GThread structures |
| * @user_data: second argument to @thread_func |
| * |
| * Call @thread_func on all existing #GThread structures. 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 |
| */ |
| 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); |
| for (thread = g_thread_all_threads; thread; thread = thread->next) |
| slist = g_slist_prepend (slist, thread); |
| G_UNLOCK (g_thread); |
| /* walk the list, skipping non-existant threads */ |
| while (slist) |
| { |
| GSList *node = slist; |
| slist = node->next; |
| /* check whether the current thread still exists */ |
| G_LOCK (g_thread); |
| for (thread = g_thread_all_threads; thread; thread = thread->next) |
| if (thread == node->data) |
| break; |
| G_UNLOCK (g_thread); |
| if (thread) |
| thread_func (thread, user_data); |
| g_slist_free_1 (node); |
| } |
| } |
| |
| /** |
| * 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 () |
| { |
| return g_thread_supported (); |
| } |