/***************************************************************************** * vlc_threads.h : threads implementation for the VideoLAN client * This header provides portable declarations for mutexes & conditions ***************************************************************************** * Copyright (C) 1999, 2002 VLC authors and VideoLAN * Copyright © 2007-2016 Rémi Denis-Courmont * * Authors: Jean-Marc Dressler * Samuel Hocevar * Gildas Bazin * Christophe Massiot * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This program 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 program; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ #ifndef VLC_THREADS_H_ #define VLC_THREADS_H_ /** * \ingroup os * \defgroup thread Threads and synchronization primitives * @{ * \file * Thread primitive declarations */ /** * Issues an explicit deferred cancellation point. * * This has no effects if thread cancellation is disabled. * This can be called when there is a rather slow non-sleeping operation. * This is also used to force a cancellation point in a function that would * otherwise not always be one (block_FifoGet() is an example). */ VLC_API void vlc_testcancel(void); #if defined (_WIN32) # include # ifndef ETIMEDOUT # define ETIMEDOUT 10060 /* This is the value in winsock.h. */ # endif typedef struct vlc_thread *vlc_thread_t; # define VLC_THREAD_CANCELED NULL # define LIBVLC_NEED_SLEEP typedef struct { bool dynamic; union { struct { bool locked; unsigned long contention; }; CRITICAL_SECTION mutex; }; } vlc_mutex_t; #define VLC_STATIC_MUTEX { false, { { false, 0 } } } #define LIBVLC_NEED_CONDVAR #define LIBVLC_NEED_SEMAPHORE #define LIBVLC_NEED_RWLOCK typedef struct vlc_threadvar *vlc_threadvar_t; typedef struct vlc_timer *vlc_timer_t; # define VLC_THREAD_PRIORITY_LOW 0 # define VLC_THREAD_PRIORITY_INPUT THREAD_PRIORITY_ABOVE_NORMAL # define VLC_THREAD_PRIORITY_AUDIO THREAD_PRIORITY_HIGHEST # define VLC_THREAD_PRIORITY_VIDEO 0 # define VLC_THREAD_PRIORITY_OUTPUT THREAD_PRIORITY_ABOVE_NORMAL # define VLC_THREAD_PRIORITY_HIGHEST THREAD_PRIORITY_TIME_CRITICAL #elif defined (__OS2__) # include typedef struct vlc_thread *vlc_thread_t; #define VLC_THREAD_CANCELED NULL typedef struct { bool dynamic; union { struct { bool locked; unsigned long contention; }; HMTX hmtx; }; } vlc_mutex_t; #define VLC_STATIC_MUTEX { false, { { false, 0 } } } typedef struct { HEV hev; unsigned waiters; HEV hevAck; unsigned signaled; } vlc_cond_t; #define VLC_STATIC_COND { NULLHANDLE, 0, NULLHANDLE, 0 } #define LIBVLC_NEED_SEMAPHORE #define LIBVLC_NEED_RWLOCK typedef struct vlc_threadvar *vlc_threadvar_t; typedef struct vlc_timer *vlc_timer_t; # define VLC_THREAD_PRIORITY_LOW 0 # define VLC_THREAD_PRIORITY_INPUT \ MAKESHORT(PRTYD_MAXIMUM / 2, PRTYC_REGULAR) # define VLC_THREAD_PRIORITY_AUDIO MAKESHORT(PRTYD_MAXIMUM, PRTYC_REGULAR) # define VLC_THREAD_PRIORITY_VIDEO 0 # define VLC_THREAD_PRIORITY_OUTPUT \ MAKESHORT(PRTYD_MAXIMUM / 2, PRTYC_REGULAR) # define VLC_THREAD_PRIORITY_HIGHEST MAKESHORT(0, PRTYC_TIMECRITICAL) # define pthread_sigmask sigprocmask static inline int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout) { static int (*vlc_poll_os2)(struct pollfd *, unsigned, int) = NULL; if (!vlc_poll_os2) { HMODULE hmod; CHAR szFailed[CCHMAXPATH]; if (DosLoadModule(szFailed, sizeof(szFailed), "vlccore", &hmod)) return -1; if (DosQueryProcAddr(hmod, 0, "_vlc_poll_os2", (PFN *)&vlc_poll_os2)) return -1; } return (*vlc_poll_os2)(fds, nfds, timeout); } # define poll(u,n,t) vlc_poll(u, n, t) #elif defined (__ANDROID__) /* pthreads subset without pthread_cancel() */ # include # include # include # define LIBVLC_USE_PTHREAD_CLEANUP 1 # define LIBVLC_NEED_SLEEP # define LIBVLC_NEED_CONDVAR # define LIBVLC_NEED_SEMAPHORE # define LIBVLC_NEED_RWLOCK typedef struct vlc_thread *vlc_thread_t; #define VLC_THREAD_CANCELED NULL typedef pthread_mutex_t vlc_mutex_t; #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER typedef pthread_key_t vlc_threadvar_t; typedef struct vlc_timer *vlc_timer_t; # define VLC_THREAD_PRIORITY_LOW 0 # define VLC_THREAD_PRIORITY_INPUT 0 # define VLC_THREAD_PRIORITY_AUDIO 0 # define VLC_THREAD_PRIORITY_VIDEO 0 # define VLC_THREAD_PRIORITY_OUTPUT 0 # define VLC_THREAD_PRIORITY_HIGHEST 0 static inline int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout) { int val; do { int ugly_timeout = ((unsigned)timeout >= 50) ? 50 : timeout; if (timeout >= 0) timeout -= ugly_timeout; vlc_testcancel (); val = poll (fds, nfds, ugly_timeout); } while (val == 0 && timeout != 0); return val; } # define poll(u,n,t) vlc_poll(u, n, t) #elif defined (__APPLE__) # define _APPLE_C_SOURCE 1 /* Proper pthread semantics on OSX */ # include # include /* Unnamed POSIX semaphores not supported on Mac OS X */ # include # include # define LIBVLC_USE_PTHREAD 1 # define LIBVLC_USE_PTHREAD_CLEANUP 1 typedef pthread_t vlc_thread_t; #define VLC_THREAD_CANCELED PTHREAD_CANCELED typedef pthread_mutex_t vlc_mutex_t; #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER typedef pthread_cond_t vlc_cond_t; #define VLC_STATIC_COND PTHREAD_COND_INITIALIZER typedef semaphore_t vlc_sem_t; typedef pthread_rwlock_t vlc_rwlock_t; #define VLC_STATIC_RWLOCK PTHREAD_RWLOCK_INITIALIZER typedef pthread_key_t vlc_threadvar_t; typedef struct vlc_timer *vlc_timer_t; # define VLC_THREAD_PRIORITY_LOW 0 # define VLC_THREAD_PRIORITY_INPUT 22 # define VLC_THREAD_PRIORITY_AUDIO 22 # define VLC_THREAD_PRIORITY_VIDEO 0 # define VLC_THREAD_PRIORITY_OUTPUT 22 # define VLC_THREAD_PRIORITY_HIGHEST 22 #else /* POSIX threads */ # include /* _POSIX_SPIN_LOCKS */ # include # include /** * Whether LibVLC threads are based on POSIX threads. */ # define LIBVLC_USE_PTHREAD 1 /** * Whether LibVLC thread cancellation is based on POSIX threads. */ # define LIBVLC_USE_PTHREAD_CLEANUP 1 /** * Thread handle. */ typedef struct { pthread_t handle; } vlc_thread_t; /** * Return value of a canceled thread. */ #define VLC_THREAD_CANCELED PTHREAD_CANCELED /** * Mutex. * * Storage space for a mutual exclusion lock. */ typedef pthread_mutex_t vlc_mutex_t; /** * Static initializer for (static) mutex. */ #define VLC_STATIC_MUTEX PTHREAD_MUTEX_INITIALIZER /** * Condition variable. * * Storage space for a thread condition variable. */ typedef pthread_cond_t vlc_cond_t; /** * Static initializer for (static) condition variable. * * \note * The condition variable will use the default clock, which is OS-dependent. * Therefore, where timed waits are necessary the condition variable should * always be initialized dynamically explicit instead of using this * initializer. */ #define VLC_STATIC_COND PTHREAD_COND_INITIALIZER /** * Semaphore. * * Storage space for a thread-safe semaphore. */ typedef sem_t vlc_sem_t; /** * Read/write lock. * * Storage space for a slim reader/writer lock. */ typedef pthread_rwlock_t vlc_rwlock_t; /** * Static initializer for (static) read/write lock. */ #define VLC_STATIC_RWLOCK PTHREAD_RWLOCK_INITIALIZER /** * Thread-local key handle. */ typedef pthread_key_t vlc_threadvar_t; /** * Threaded timer handle. */ typedef struct vlc_timer *vlc_timer_t; # define VLC_THREAD_PRIORITY_LOW 0 # define VLC_THREAD_PRIORITY_INPUT 10 # define VLC_THREAD_PRIORITY_AUDIO 5 # define VLC_THREAD_PRIORITY_VIDEO 0 # define VLC_THREAD_PRIORITY_OUTPUT 15 # define VLC_THREAD_PRIORITY_HIGHEST 20 #endif #ifdef LIBVLC_NEED_CONDVAR typedef struct { unsigned value; } vlc_cond_t; # define VLC_STATIC_COND { 0 } #endif #ifdef LIBVLC_NEED_SEMAPHORE typedef struct vlc_sem { vlc_mutex_t lock; vlc_cond_t wait; unsigned value; } vlc_sem_t; #endif #ifdef LIBVLC_NEED_RWLOCK typedef struct vlc_rwlock { vlc_mutex_t mutex; vlc_cond_t wait; long state; } vlc_rwlock_t; # define VLC_STATIC_RWLOCK { VLC_STATIC_MUTEX, VLC_STATIC_COND, 0 } #endif /** * Initializes a fast mutex. * * Recursive locking of a fast mutex is undefined behaviour. (In debug builds, * recursive locking will cause an assertion failure.) */ VLC_API void vlc_mutex_init(vlc_mutex_t *); /** * Initializes a recursive mutex. * \warning This is strongly discouraged. Please use normal mutexes. */ VLC_API void vlc_mutex_init_recursive(vlc_mutex_t *); /** * Deinitializes a mutex. * * The mutex must not be locked, otherwise behaviour is undefined. */ VLC_API void vlc_mutex_destroy(vlc_mutex_t *); /** * Acquires a mutex. * * If needed, this waits for any other thread to release it. * * \warning Beware of deadlocks when locking multiple mutexes at the same time, * or when using mutexes from callbacks. * * \note This function is not a cancellation point. */ VLC_API void vlc_mutex_lock(vlc_mutex_t *); /** * Tries to acquire a mutex. * * This function acquires the mutex if and only if it is not currently held by * another thread. This function never sleeps and can be used in delay-critical * code paths. * * \note This function is not a cancellation point. * * \warning If this function fails, then the mutex is held... by another * thread. The calling thread must deal with the error appropriately. That * typically implies postponing the operations that would have required the * mutex. If the thread cannot defer those operations, then it must use * vlc_mutex_lock(). If in doubt, use vlc_mutex_lock() instead. * * @return 0 if the mutex could be acquired, an error code otherwise. */ VLC_API int vlc_mutex_trylock( vlc_mutex_t * ) VLC_USED; /** * Releases a mutex. * * If the mutex is not held by the calling thread, the behaviour is undefined. * * \note This function is not a cancellation point. */ VLC_API void vlc_mutex_unlock(vlc_mutex_t *); /** * Initializes a condition variable. */ VLC_API void vlc_cond_init(vlc_cond_t *); /** * Initializes a condition variable (wall clock). * * This function initializes a condition variable for timed waiting using the * UTC wall clock time. The time reference is the same as with time() and with * timespec_get() and TIME_UTC. * vlc_cond_timedwait_daytime() must be instead of * vlc_cond_timedwait() for actual waiting. */ void vlc_cond_init_daytime(vlc_cond_t *); /** * Deinitializes a condition variable. * * No threads shall be waiting or signaling the condition, otherwise the * behavior is undefined. */ VLC_API void vlc_cond_destroy(vlc_cond_t *); /** * Wakes up one thread waiting on a condition variable. * * If any thread is currently waiting on the condition variable, at least one * of those threads will be woken up. Otherwise, this function has no effects. * * \note This function is not a cancellation point. */ VLC_API void vlc_cond_signal(vlc_cond_t *); /** * Wakes up all threads waiting on a condition variable. * * \note This function is not a cancellation point. */ VLC_API void vlc_cond_broadcast(vlc_cond_t *); /** * Waits on a condition variable. * * The calling thread will be suspended until another thread calls * vlc_cond_signal() or vlc_cond_broadcast() on the same condition variable, * the thread is cancelled with vlc_cancel(), or the system causes a * spurious unsolicited wake-up. * * A mutex is needed to wait on a condition variable. It must not be * a recursive mutex. Although it is possible to use the same mutex for * multiple condition, it is not valid to use different mutexes for the same * condition variable at the same time from different threads. * * The canonical way to use a condition variable to wait for event foobar is: @code vlc_mutex_lock(&lock); mutex_cleanup_push(&lock); // release the mutex in case of cancellation while (!foobar) vlc_cond_wait(&wait, &lock); // -- foobar is now true, do something about it here -- vlc_cleanup_pop(); vlc_mutex_unlock(&lock); @endcode * * \note This function is a cancellation point. In case of thread cancellation, * the mutex is always locked before cancellation proceeds. * * \param cond condition variable to wait on * \param mutex mutex which is unlocked while waiting, * then locked again when waking up. */ VLC_API void vlc_cond_wait(vlc_cond_t *cond, vlc_mutex_t *mutex); /** * Waits on a condition variable up to a certain date. * * This works like vlc_cond_wait() but with an additional time-out. * The time-out is expressed as an absolute timestamp using the same arbitrary * time reference as the mdate() and mwait() functions. * * \note This function is a cancellation point. In case of thread cancellation, * the mutex is always locked before cancellation proceeds. * * \param cond condition variable to wait on * \param mutex mutex which is unlocked while waiting, * then locked again when waking up * \param deadline absolute timeout * * \warning If the variable was initialized with vlc_cond_init_daytime(), or * was statically initialized with \ref VLC_STATIC_COND, the time reference * used by this function is unspecified (depending on the implementation, it * might be the Unix epoch or the mdate() clock). * * \return 0 if the condition was signaled, an error code in case of timeout. */ VLC_API int vlc_cond_timedwait(vlc_cond_t *cond, vlc_mutex_t *mutex, mtime_t deadline); int vlc_cond_timedwait_daytime(vlc_cond_t *, vlc_mutex_t *, time_t); /** * Initializes a semaphore. * * @param count initial semaphore value (typically 0) */ VLC_API void vlc_sem_init(vlc_sem_t *, unsigned count); /** * Deinitializes a semaphore. */ VLC_API void vlc_sem_destroy(vlc_sem_t *); /** * Increments the value of a semaphore. * * \note This function is not a cancellation point. * * \return 0 on success, EOVERFLOW in case of integer overflow. */ VLC_API int vlc_sem_post(vlc_sem_t *); /** * Waits on a semaphore. * * This function atomically waits for the semaphore to become non-zero then * decrements it, and returns. If the semaphore is non-zero on entry, it is * immediately decremented. * * \note This function may be a point of cancellation. */ VLC_API void vlc_sem_wait(vlc_sem_t *); /** * Initializes a read/write lock. */ VLC_API void vlc_rwlock_init(vlc_rwlock_t *); /** * Destroys an initialized unused read/write lock. */ VLC_API void vlc_rwlock_destroy(vlc_rwlock_t *); /** * Acquires a read/write lock for reading. * * \note Recursion is allowed. * \note This function may be a point of cancellation. */ VLC_API void vlc_rwlock_rdlock(vlc_rwlock_t *); /** * Acquires a read/write lock for writing. Recursion is not allowed. * \note This function may be a point of cancellation. */ VLC_API void vlc_rwlock_wrlock(vlc_rwlock_t *); /** * Releases a read/write lock. * * The calling thread must hold the lock. Otherwise behaviour is undefined. * * \note This function is not a cancellation point. */ VLC_API void vlc_rwlock_unlock(vlc_rwlock_t *); /** * Allocates a thread-specific variable. * * @param key where to store the thread-specific variable handle * @param destr a destruction callback. It is called whenever a thread exits * and the thread-specific variable has a non-NULL value. * * @return 0 on success, a system error code otherwise. * This function can actually fail: on most systems, there is a fixed limit to * the number of thread-specific variables in a given process. */ VLC_API int vlc_threadvar_create(vlc_threadvar_t *key, void (*destr) (void *)); /** * Deallocates a thread-specific variable. */ VLC_API void vlc_threadvar_delete(vlc_threadvar_t *); /** * Sets a thread-specific variable. * \param key thread-local variable key (created with vlc_threadvar_create()) * \param value new value for the variable for the calling thread * \return 0 on success, a system error code otherwise. */ VLC_API int vlc_threadvar_set(vlc_threadvar_t key, void *value); /** * Gets the value of a thread-local variable for the calling thread. * This function cannot fail. * * \return the value associated with the given variable for the calling * or NULL if no value was set. */ VLC_API void *vlc_threadvar_get(vlc_threadvar_t); /** * Waits on an address. * * Puts the calling thread to sleep if a specific value is stored at a * specified address. The thread will sleep until it is woken up by a call to * vlc_addr_signal() or vlc_addr_broadcast() in another thread, or spuriously. * * If the value does not match, do nothing and return immediately. * * \param addr address to check for * \param val value to match at the address */ void vlc_addr_wait(void *addr, unsigned val); /** * Waits on an address with a time-out. * * This function operates as vlc_addr_wait() but provides an additional * time-out. If the time-out elapses, the thread resumes and the function * returns. * * \param addr address to check for * \param val value to match at the address * \param delay time-out duration * * \return true if the function was woken up before the time-out, * false if the time-out elapsed. */ bool vlc_addr_timedwait(void *addr, unsigned val, mtime_t delay); /** * Wakes up one thread on an address. * * Wakes up (at least) one of the thread sleeping on the specified address. * The address must be equal to the first parameter given by at least one * thread sleeping within the vlc_addr_wait() or vlc_addr_timedwait() * functions. If no threads are found, this function does nothing. * * \param addr address identifying which threads may be woken up */ void vlc_addr_signal(void *addr); /** * Wakes up all thread on an address. * * Wakes up all threads sleeping on the specified address (if any). * Any thread sleeping within a call to vlc_addr_wait() or vlc_addr_timedwait() * with the specified address as first call parameter will be woken up. * * \param addr address identifying which threads to wake up */ void vlc_addr_broadcast(void *addr); /** * Creates and starts a new thread. * * The thread must be joined with vlc_join() to reclaim resources * when it is not needed anymore. * * @param th storage space for the handle of the new thread (cannot be NULL) * [OUT] * @param entry entry point for the thread * @param data data parameter given to the entry point * @param priority thread priority value * @return 0 on success, a standard error code on error. * @note In case of error, the value of *th is undefined. */ VLC_API int vlc_clone(vlc_thread_t *th, void *(*entry)(void *), void *data, int priority) VLC_USED; /** * Marks a thread as cancelled. * * Next time the target thread reaches a cancellation point (while not having * disabled cancellation), it will run its cancellation cleanup handler, the * thread variable destructors, and terminate. * * vlc_join() must be used regardless of a thread being cancelled or not, to * avoid leaking resources. */ VLC_API void vlc_cancel(vlc_thread_t); /** * Waits for a thread to complete (if needed), then destroys it. * * \note This is a cancellation point. In case of cancellation, the thread is * not joined. * \warning A thread cannot join itself (normally VLC will abort if this is * attempted). Also a detached thread cannot be joined. * * @param th thread handle * @param result [OUT] pointer to write the thread return value or NULL */ VLC_API void vlc_join(vlc_thread_t th, void **result); /** * Disables thread cancellation. * * This functions saves the current cancellation state (enabled or disabled), * then disables cancellation for the calling thread. It must be called before * entering a piece of code that is not cancellation-safe, unless it can be * proven that the calling thread will not be cancelled. * * \note This function is not a cancellation point. * * \return Previous cancellation state (opaque value for vlc_restorecancel()). */ VLC_API int vlc_savecancel(void); /** * Restores the cancellation state. * * This function restores the cancellation state of the calling thread to * a state previously saved by vlc_savecancel(). * * \note This function is not a cancellation point. * * \param state previous state as returned by vlc_savecancel(). */ VLC_API void vlc_restorecancel(int state); /** * Internal handler for thread cancellation. * * Do not call this function directly. Use wrapper macros instead: * vlc_cleanup_push(), vlc_cleanup_pop(). */ VLC_API void vlc_control_cancel(int cmd, ...); /** * Thread handle. * * This function returns the thread handle of the calling thread. * * \note The exact type of the thread handle depends on the platform, * including an integer type, a pointer type or a compound type of any size. * If you need an integer identifier, use vlc_thread_id() instead. * * \note vlc_join(vlc_thread_self(), NULL) is undefined, * as it obviously does not make any sense (it might result in a deadlock, but * there are no warranties that it will). * * \return the thread handle */ VLC_API vlc_thread_t vlc_thread_self(void) VLC_USED; /** * Thread identifier. * * This function returns the identifier of the calling thread. The identifier * cannot change for the entire duration of the thread, and no other thread can * have the same identifier at the same time in the same process. Typically, * the identifier is also unique across all running threads of all existing * processes, but that depends on the operating system. * * There are no particular semantics to the thread ID with LibVLC. * It is provided mainly for tracing and debugging. * * \warning This function is not currently implemented on all supported * platforms. Where not implemented, it returns (unsigned long)-1. * * \return the thread identifier (or -1 if unimplemented) */ VLC_API unsigned long vlc_thread_id(void) VLC_USED; /** * Precision monotonic clock. * * In principles, the clock has a precision of 1 MHz. But the actual resolution * may be much lower, especially when it comes to sleeping with mwait() or * msleep(). Most general-purpose operating systems provide a resolution of * only 100 to 1000 Hz. * * \warning The origin date (time value "zero") is not specified. It is * typically the time the kernel started, but this is platform-dependent. * If you need wall clock time, use gettimeofday() instead. * * \return a timestamp in microseconds. */ VLC_API mtime_t mdate(void); /** * Waits until a deadline. * * \param deadline timestamp to wait for (\ref mdate()) * * \note The deadline may be exceeded due to OS scheduling. * \note This function is a cancellation point. */ VLC_API void mwait(mtime_t deadline); /** * Waits for an interval of time. * * \param delay how long to wait (in microseconds) * * \note The delay may be exceeded due to OS scheduling. * \note This function is a cancellation point. */ VLC_API void msleep(mtime_t delay); #define VLC_HARD_MIN_SLEEP 10000 /* 10 milliseconds = 1 tick at 100Hz */ #define VLC_SOFT_MIN_SLEEP 9000000 /* 9 seconds */ #if defined (__GNUC__) && !defined (__clang__) /* Linux has 100, 250, 300 or 1000Hz * * HZ=100 by default on FreeBSD, but some architectures use a 1000Hz timer */ static __attribute__((unused)) __attribute__((noinline)) __attribute__((error("sorry, cannot sleep for such short a time"))) mtime_t impossible_delay( mtime_t delay ) { (void) delay; return VLC_HARD_MIN_SLEEP; } static __attribute__((unused)) __attribute__((noinline)) __attribute__((warning("use proper event handling instead of short delay"))) mtime_t harmful_delay( mtime_t delay ) { return delay; } # define check_delay( d ) \ ((__builtin_constant_p(d < VLC_HARD_MIN_SLEEP) \ && (d < VLC_HARD_MIN_SLEEP)) \ ? impossible_delay(d) \ : ((__builtin_constant_p(d < VLC_SOFT_MIN_SLEEP) \ && (d < VLC_SOFT_MIN_SLEEP)) \ ? harmful_delay(d) \ : d)) static __attribute__((unused)) __attribute__((noinline)) __attribute__((error("deadlines can not be constant"))) mtime_t impossible_deadline( mtime_t deadline ) { return deadline; } # define check_deadline( d ) \ (__builtin_constant_p(d) ? impossible_deadline(d) : d) #else # define check_delay(d) (d) # define check_deadline(d) (d) #endif /** * Initializes an asynchronous timer. * * \param id pointer to timer to be initialized * \param func function that the timer will call * \param data parameter for the timer function * \return 0 on success, a system error code otherwise. * * \warning Asynchronous timers are processed from an unspecified thread. * \note Multiple occurrences of a single interval timer are serialized: * they cannot run concurrently. */ VLC_API int vlc_timer_create(vlc_timer_t *id, void (*func)(void *), void *data) VLC_USED; /** * Destroys an initialized timer. * * If needed, the timer is first disarmed. Behaviour is undefined if the * specified timer is not initialized. * * \warning This function must be called before the timer data can be * freed and before the timer callback function can be unmapped/unloaded. * * \param timer timer to destroy */ VLC_API void vlc_timer_destroy(vlc_timer_t timer); /** * Arms or disarms an initialized timer. * * This functions overrides any previous call to itself. * * \note A timer can fire later than requested due to system scheduling * limitations. An interval timer can fail to trigger sometimes, either because * the system is busy or suspended, or because a previous iteration of the * timer is still running. See also vlc_timer_getoverrun(). * * \param timer initialized timer * \param absolute the timer value origin is the same as mdate() if true, * the timer value is relative to now if false. * \param value zero to disarm the timer, otherwise the initial time to wait * before firing the timer. * \param interval zero to fire the timer just once, otherwise the timer * repetition interval. */ VLC_API void vlc_timer_schedule(vlc_timer_t timer, bool absolute, mtime_t value, mtime_t interval); /** * Fetches and resets the overrun counter for a timer. * * This functions returns the number of times that the interval timer should * have fired, but the callback was not invoked due to scheduling problems. * The call resets the counter to zero. * * \param timer initialized timer * \return the timer overrun counter (typically zero) */ VLC_API unsigned vlc_timer_getoverrun(vlc_timer_t) VLC_USED; /** * Count CPUs. * * \return number of available (logical) CPUs. */ VLC_API unsigned vlc_GetCPUCount(void); enum { VLC_CLEANUP_PUSH, VLC_CLEANUP_POP, VLC_CANCEL_ADDR_SET, VLC_CANCEL_ADDR_CLEAR, }; #if defined (LIBVLC_USE_PTHREAD_CLEANUP) /** * Registers a thread cancellation handler. * * This pushes a function to run if the thread is cancelled (or otherwise * exits prematurely). * * If multiple procedures are registered, * they are handled in last-in first-out order. * * \note Any call to vlc_cleanup_push() must paired with a call to * vlc_cleanup_pop(). * \warning Branching into or out of the block between these two function calls * is not allowed (read: it will likely crash the whole process). * * \param routine procedure to call if the thread ends * \param arg argument for the procedure */ # define vlc_cleanup_push( routine, arg ) pthread_cleanup_push (routine, arg) /** * Unregisters the last cancellation handler. * * This pops the cancellation handler that was last pushed with * vlc_cleanup_push() in the calling thread. */ # define vlc_cleanup_pop( ) pthread_cleanup_pop (0) #else typedef struct vlc_cleanup_t vlc_cleanup_t; struct vlc_cleanup_t { vlc_cleanup_t *next; void (*proc) (void *); void *data; }; /* This macros opens a code block on purpose. This is needed for multiple * calls within a single function. This also prevent Win32 developers from * writing code that would break on POSIX (POSIX opens a block as well). */ # define vlc_cleanup_push( routine, arg ) \ do { \ vlc_cleanup_t vlc_cleanup_data = { NULL, routine, arg, }; \ vlc_control_cancel (VLC_CLEANUP_PUSH, &vlc_cleanup_data) # define vlc_cleanup_pop( ) \ vlc_control_cancel (VLC_CLEANUP_POP); \ } while (0) #endif /* !LIBVLC_USE_PTHREAD_CLEANUP */ static inline void vlc_cleanup_lock (void *lock) { vlc_mutex_unlock ((vlc_mutex_t *)lock); } #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock) static inline void vlc_cancel_addr_set(void *addr) { vlc_control_cancel(VLC_CANCEL_ADDR_SET, addr); } static inline void vlc_cancel_addr_clear(void *addr) { vlc_control_cancel(VLC_CANCEL_ADDR_CLEAR, addr); } #ifdef __cplusplus /** * Helper C++ class to lock a mutex. * * The mutex is locked when the object is created, and unlocked when the object * is destroyed. */ class vlc_mutex_locker { private: vlc_mutex_t *lock; public: vlc_mutex_locker (vlc_mutex_t *m) : lock (m) { vlc_mutex_lock (lock); } ~vlc_mutex_locker (void) { vlc_mutex_unlock (lock); } }; #endif enum { VLC_AVCODEC_MUTEX = 0, VLC_GCRYPT_MUTEX, VLC_XLIB_MUTEX, VLC_MOSAIC_MUTEX, VLC_HIGHLIGHT_MUTEX, #ifdef _WIN32 VLC_MTA_MUTEX, #endif /* Insert new entry HERE */ VLC_MAX_MUTEX }; /** * Internal handler for global mutexes. * * Do not use this function directly. Use helper macros instead: * vlc_global_lock(), vlc_global_unlock(). */ VLC_API void vlc_global_mutex(unsigned, bool); /** * Acquires a global mutex. */ #define vlc_global_lock( n ) vlc_global_mutex(n, true) /** * Releases a global mutex. */ #define vlc_global_unlock( n ) vlc_global_mutex(n, false) /** @} */ #endif /* !_VLC_THREADS_H */