Multi reader/writer cache/buffer

media/blink/waiter_index.h

Index: media/blink/waiter_index.h
diff --git a/media/blink/waiter_index.h b/media/blink/waiter_index.h
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+// Copyright 2013 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 MEDIA_BLINK_WAITER_INDEX_H_
+#define MEDIA_BLINK_WAITER_INDEX_H_
+
+#include <map>
+#include <set>
+
+namespace media {
+
+class Waiter {
+public:
+  virtual ~Waiter() {}
+  virtual void Continue() = 0;
+};
+
+class WaiterIndex {
+public:
+  WaiterIndex();
+  ~WaiterIndex();
+  // Register a waiter at position |pos|.
+  void WaitFor(int32_t pos, Waiter* waiter);
+  // Unregister a waiter, |pos| should be the same
+  // position as given to WaitFor().
+  void StopWaitFor(int32_t pos, Waiter* waiter);
+  // Wake up all waiters waiting at |pos|.
+  void WakeUp(int32_t pos);
+  // Delete all waiters. Makes it possible for
+  // for this class to own waiters.
+  void DeleteWaiters();
+
+  const std::map<int32_t, std::set<Waiter*> > map() const {
+    return waiters_;
+  }
+
+ private:
+  std::map<int32_t, std::set<Waiter*> > waiters_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BLINK_WAITER_INDEX_H