libwebp: update to 0.4.1

third_party/libwebp/utils/thread.h

Index: third_party/libwebp/utils/thread.h
diff --git a/third_party/libwebp/utils/thread.h b/third_party/libwebp/utils/thread.h
index aef33bdaf21f18fe896485e4818b1e851bb10b52..7bd451b124ae3b81596abfbcc823e3cb129d3a38 100644
--- a/third_party/libwebp/utils/thread.h
+++ b/third_party/libwebp/utils/thread.h
@@ -15,33 +15,15 @@
 #define WEBP_UTILS_THREAD_H_
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include "../webp/config.h"
 #endif
 
+#include "../webp/types.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#ifdef WEBP_USE_THREAD
-
-#if defined(_WIN32)
-
-#include <windows.h>
-typedef HANDLE pthread_t;
-typedef CRITICAL_SECTION pthread_mutex_t;
-typedef struct {
-  HANDLE waiting_sem_;
-  HANDLE received_sem_;
-  HANDLE signal_event_;
-} pthread_cond_t;
-
-#else
-
-#include <pthread.h>
-
-#endif    /* _WIN32 */
-#endif    /* WEBP_USE_THREAD */
-
 // State of the worker thread object
 typedef enum {
   NOT_OK = 0,   // object is unusable
@@ -53,13 +35,12 @@ typedef enum {
 // arguments (data1 and data2), and should return false in case of error.
 typedef int (*WebPWorkerHook)(void*, void*);
 
-// Synchronize object used to launch job in the worker thread
+// Platform-dependent implementation details for the worker.
+typedef struct WebPWorkerImpl WebPWorkerImpl;
+
+// Synchronization object used to launch job in the worker thread
 typedef struct {
-#ifdef WEBP_USE_THREAD
-  pthread_mutex_t mutex_;
-  pthread_cond_t  condition_;
-  pthread_t       thread_;
-#endif
+  WebPWorkerImpl* impl_;
   WebPWorkerStatus status_;
   WebPWorkerHook hook;    // hook to call
   void* data1;            // first argument passed to 'hook'
@@ -67,26 +48,41 @@ typedef struct {
   int had_error;          // return value of the last call to 'hook'
 } WebPWorker;
 
-// Must be called first, before any other method.
-void WebPWorkerInit(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 WebPWorkerReset(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 WebPWorkerSync(WebPWorker* const worker);
-// Triggers the thread to call hook() with data1 and data2 argument. These
-// hook/data1/data2 can be changed at any time before calling this function,
-// but not be changed afterward until the next call to WebPWorkerSync().
-void WebPWorkerLaunch(WebPWorker* const worker);
-// This function is similar to WebPWorkerLaunch() except that it calls the
-// hook directly instead of using a thread. Convenient to bypass the thread
-// mechanism while still using the WebPWorker structs. WebPWorkerSync() must
-// still be called afterward (for error reporting).
-void WebPWorkerExecute(WebPWorker* const worker);
-// Kill the thread and terminate the object. To use the object again, one
-// must call WebPWorkerReset() again.
-void WebPWorkerEnd(WebPWorker* const worker);
+// 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 interface);
+
+// Retrieve the currently set thread worker interface.
+WEBP_EXTERN(const WebPWorkerInterface*) WebPGetWorkerInterface(void);
 
 //------------------------------------------------------------------------------