1 // Copyright 2013 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // Multi-threaded worker 11 // 12 // Original source: 13 // https://chromium.googlesource.com/webm/libwebp 14 15 #ifndef VPX_VPX_UTIL_VPX_THREAD_H_ 16 #define VPX_VPX_UTIL_VPX_THREAD_H_ 17 18 #ifdef __cplusplus 19 extern "C" { 20 #endif 21 22 // State of the worker thread object 23 typedef enum { 24 VPX_WORKER_STATUS_NOT_OK = 0, // object is unusable 25 VPX_WORKER_STATUS_OK, // ready to work 26 VPX_WORKER_STATUS_WORKING // busy finishing the current task 27 } VPxWorkerStatus; 28 29 // Function to be called by the worker thread. Takes two opaque pointers as 30 // arguments (data1 and data2). Should return true on success and return false 31 // in case of error. 32 typedef int (*VPxWorkerHook)(void *, void *); 33 34 // Platform-dependent implementation details for the worker. 35 typedef struct VPxWorkerImpl VPxWorkerImpl; 36 37 // Synchronization object used to launch job in the worker thread 38 typedef struct { 39 VPxWorkerImpl *impl_; 40 VPxWorkerStatus status_; 41 // Thread name for the debugger. If not NULL, must point to a string that 42 // outlives the worker thread. For portability, use a name <= 15 characters 43 // long (not including the terminating NUL character). 44 const char *thread_name; 45 VPxWorkerHook hook; // hook to call 46 void *data1; // first argument passed to 'hook' 47 void *data2; // second argument passed to 'hook' 48 int had_error; // true if a call to 'hook' returned false 49 } VPxWorker; 50 51 // The interface for all thread-worker related functions. All these functions 52 // must be implemented. 53 typedef struct { 54 // Must be called first, before any other method. 55 void (*init)(VPxWorker *const worker); 56 // Must be called to initialize the object and spawn the thread. Re-entrant. 57 // Will potentially launch the thread. Returns false in case of error. 58 int (*reset)(VPxWorker *const worker); 59 // Makes sure the previous work is finished. Returns true if worker->had_error 60 // was not set and no error condition was triggered by the working thread. 61 int (*sync)(VPxWorker *const worker); 62 // Triggers the thread to call hook() with data1 and data2 arguments. These 63 // hook/data1/data2 values can be changed at any time before calling this 64 // function, but not be changed afterward until the next call to Sync(). 65 void (*launch)(VPxWorker *const worker); 66 // This function is similar to launch() except that it calls the 67 // hook directly instead of using a thread. Convenient to bypass the thread 68 // mechanism while still using the VPxWorker structs. sync() must 69 // still be called afterward (for error reporting). 70 void (*execute)(VPxWorker *const worker); 71 // Kill the thread and terminate the object. To use the object again, one 72 // must call reset() again. 73 void (*end)(VPxWorker *const worker); 74 } VPxWorkerInterface; 75 76 // Install a new set of threading functions, overriding the defaults. This 77 // should be done before any workers are started, i.e., before any encoding or 78 // decoding takes place. The contents of the interface struct are copied, it 79 // is safe to free the corresponding memory after this call. This function is 80 // not thread-safe. Return false in case of invalid pointer or methods. 81 int vpx_set_worker_interface(const VPxWorkerInterface *const winterface); 82 83 // Retrieve the currently set thread worker interface. 84 const VPxWorkerInterface *vpx_get_worker_interface(void); 85 86 //------------------------------------------------------------------------------ 87 88 #ifdef __cplusplus 89 } // extern "C" 90 #endif 91 92 #endif // VPX_VPX_UTIL_VPX_THREAD_H_ 93