1 files changed, 64 insertions, 0 deletions
diff --git a/ppapi/c/pp_completion_callback.h b/ppapi/c/pp_completion_callback.h
new file mode 100644
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+++ b/ppapi/c/pp_completion_callback.h
@@ -0,0 +1,64 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_C_PP_COMPLETION_CALLBACK_H_
+#define PPAPI_C_PP_COMPLETION_CALLBACK_H_
+
+/**
+ * @file
+ * Defines the API ...
+ *
+ * @addtogroup PP
+ * @{
+ */
+
+#include <stdlib.h>
+
+#include "ppapi/c/pp_stdint.h"
+
+typedef void (*PP_CompletionCallback_Func)(void* user_data, int32_t result);
+
+/**
+ * Any method that takes a PP_CompletionCallback has the option of completing
+ * asynchronously if the operation would block.  Such a method should return
+ * PP_Error_WouldBlock to indicate when the method will complete
+ * asynchronously.  If the completion callback is NULL, then the operation will
+ * block if necessary to complete its work.  PP_BlockUntilComplete() provides a
+ * convenient way to specify blocking behavior.
+ *
+ * The result parameter passes an int32_t that if negative indicates an error
+ * code.  Otherwise the result value indicates success.  If it is a positive
+ * value then it may carry additional information.
+ */
+struct PP_CompletionCallback {
+  PP_CompletionCallback_Func func;
+  void* user_data;
+};
+
+inline struct PP_CompletionCallback PP_MakeCompletionCallback(
+    PP_CompletionCallback_Func func,
+    void* user_data) {
+  struct PP_CompletionCallback cc = { func, user_data };
+  return cc;
+}
+
+inline void PP_RunCompletionCallback(struct PP_CompletionCallback* cc,
+                                     int32_t res) {
+  cc->func(cc->user_data, res);
+}
+
+/**
+ * Use this in place of an actual completion callback to request blocking
+ * behavior.  If specified, the calling thread will block until a method
+ *  completes.  This is only usable from background threads.
+ */
+inline struct PP_CompletionCallback PP_BlockUntilComplete() {
+  return PP_MakeCompletionCallback(NULL, NULL);
+}
+
+/**
+ * @}
+ * End of addtogroup PP
+ */
+#endif  // PPAPI_C_PP_COMPLETION_CALLBACK_H_