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/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
//
// Multi-threaded worker
//
// Original source:
// https://chromium.googlesource.com/webm/libwebp
#ifndef AOM_AOM_UTIL_AOM_THREAD_H_
#define AOM_AOM_UTIL_AOM_THREAD_H_
#ifdef __cplusplus
extern "C" {
#endif
// State of the worker thread object
typedef enum {
AVX_WORKER_STATUS_NOT_OK = 0, // object is unusable
AVX_WORKER_STATUS_OK, // ready to work
AVX_WORKER_STATUS_WORKING // busy finishing the current task
} AVxWorkerStatus;
// Function to be called by the worker thread. Takes two opaque pointers as
// arguments (data1 and data2). Should return true on success and return false
// in case of error.
typedef int (*AVxWorkerHook)(void *, void *);
// Platform-dependent implementation details for the worker.
typedef struct AVxWorkerImpl AVxWorkerImpl;
// Synchronization object used to launch job in the worker thread
typedef struct {
AVxWorkerImpl *impl_;
AVxWorkerStatus status_;
// Thread name for the debugger. If not NULL, must point to a string that
// outlives the worker thread. For portability, use a name <= 15 characters
// long (not including the terminating NUL character).
const char *thread_name;
AVxWorkerHook hook; // hook to call
void *data1; // first argument passed to 'hook'
void *data2; // second argument passed to 'hook'
int had_error; // true if a call to 'hook' returned false
} AVxWorker;
// The interface for all thread-worker related functions. All these functions
// must be implemented.
typedef struct {
// Must be called first, before any other method.
void (*init)(AVxWorker *const worker);
// Must be called to initialize the object and spawn the thread. Re-entrant.
// Will potentially launch the thread. Returns false in case of error.
int (*reset)(AVxWorker *const worker);
// Makes sure the previous work is finished. Returns true if worker->had_error
// was not set and no error condition was triggered by the working thread.
int (*sync)(AVxWorker *const worker);
// Triggers the thread to call hook() with data1 and data2 arguments. These
// hook/data1/data2 values can be changed at any time before calling this
// function, but not be changed afterward until the next call to Sync().
void (*launch)(AVxWorker *const worker);
// This function is similar to launch() except that it calls the
// hook directly instead of using a thread. Convenient to bypass the thread
// mechanism while still using the AVxWorker structs. sync() must
// still be called afterward (for error reporting).
void (*execute)(AVxWorker *const worker);
// Kill the thread and terminate the object. To use the object again, one
// must call reset() again.
void (*end)(AVxWorker *const worker);
} AVxWorkerInterface;
// Install a new set of threading functions, overriding the defaults. This
// should be done before any workers are started, i.e., before any encoding or
// decoding takes place. The contents of the interface struct are copied, it
// is safe to free the corresponding memory after this call. This function is
// not thread-safe. Return false in case of invalid pointer or methods.
int aom_set_worker_interface(const AVxWorkerInterface *const winterface);
// Retrieve the currently set thread worker interface.
const AVxWorkerInterface *aom_get_worker_interface(void);
//------------------------------------------------------------------------------
#ifdef __cplusplus
} // extern "C"
#endif
#endif // AOM_AOM_UTIL_AOM_THREAD_H_