libwebp-0.6.0-rc1

third_party/libwebp/utils/thread.h

-// Copyright 2011 Google Inc. All Rights Reserved.
-//
-// Use of this source code is governed by a BSD-style license
-// that can be found in the COPYING file in the root of the source
-// tree. An additional intellectual property rights grant can be found
-// in the file PATENTS. All contributing project authors may
-// be found in the AUTHORS file in the root of the source tree.
-// -----------------------------------------------------------------------------
-//
-// Multi-threaded worker
-//
-// Author: Skal (pascal.massimino@gmail.com)
-
-#ifndef WEBP_UTILS_THREAD_H_
-#define WEBP_UTILS_THREAD_H_
-
-#ifdef HAVE_CONFIG_H
-#include "../webp/config.h"
-#endif
-
-#include "../webp/types.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// State of the worker thread object
-typedef enum {
-  NOT_OK = 0,   // object is unusable
-  OK,           // ready to work
-  WORK          // busy finishing the current task
-} WebPWorkerStatus;
-
-// Function to be called by the worker thread. Takes two opaque pointers as
-// arguments (data1 and data2), and should return false in case of error.
-typedef int (*WebPWorkerHook)(void*, void*);
-
-// Platform-dependent implementation details for the worker.
-typedef struct WebPWorkerImpl WebPWorkerImpl;
-
-// Synchronization object used to launch job in the worker thread
-typedef struct {
-  WebPWorkerImpl* impl_;
-  WebPWorkerStatus status_;
-  WebPWorkerHook hook;    // hook to call
-  void* data1;            // first argument passed to 'hook'
-  void* data2;            // second argument passed to 'hook'
-  int had_error;          // return value of the last call to 'hook'
-} WebPWorker;
-
-// 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)(WebPWorker* 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)(WebPWorker* 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)(WebPWorker* 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)(WebPWorker* 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 WebPWorker structs. Sync() must
-  // still be called afterward (for error reporting).
-  void (*Execute)(WebPWorker* const worker);
-  // Kill the thread and terminate the object. To use the object again, one
-  // must call Reset() again.
-  void (*End)(WebPWorker* const worker);
-} WebPWorkerInterface;
-
-// 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.
-WEBP_EXTERN(int) WebPSetWorkerInterface(
-    const WebPWorkerInterface* const winterface);
-
-// Retrieve the currently set thread worker interface.
-WEBP_EXTERN(const WebPWorkerInterface*) WebPGetWorkerInterface(void);
-
-//------------------------------------------------------------------------------
-
-#ifdef __cplusplus
-}    // extern "C"
-#endif
-
-#endif  /* WEBP_UTILS_THREAD_H_ */