git-svn-id: http://webrtc.googlecode.com/svn/trunk@6 4adac7df-926f-26a2-2b94-8c16560cd09d

system_wrappers/interface/event_wrapper.h

@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE 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.
+ */
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_
+
+namespace webrtc {
+enum EventTypeWrapper
+{
+    kEventSignaled = 1,
+    kEventError = 2,
+    kEventTimeout = 3
+};
+
+#define WEBRTC_EVENT_10_SEC   10000
+#define WEBRTC_EVENT_INFINITE 0xffffffff
+
+class EventWrapper
+{
+public:
+    // Factory method. Constructor disabled.
+    static EventWrapper* Create();
+    virtual ~EventWrapper() {}
+
+    // Releases threads who are calling Wait() and has started waiting. Please
+    // note that a thread calling Wait() will not start waiting immediately.
+    // assumptions to the contrary is a very common source of issues in
+    // multithreaded programming.
+    // Set is sticky in the sense that it will release at least one thread
+    // either immediately or some time in the future.
+    virtual bool Set() = 0;
+
+    // Prevents future Wait() calls from finishing without a new Set() call.
+    virtual bool Reset() = 0;
+
+    // Puts the calling thread into a wait state. The thread may be released
+    // by a Set() call depending on if other threads are waiting and if so on
+    // timing. The thread that was released will call Reset() before leaving
+    // preventing more threads from being released. If multiple threads
+    // are waiting for the same Set(), only one (random) thread is guaranteed to
+    // be released. It is possible that multiple (random) threads are released
+    // Depending on timing.
+    virtual EventTypeWrapper Wait(unsigned long maxTime) = 0;
+
+    // Starts a timer that will call a non-sticky version of Set() either once
+    // or periodically. If the timer is periodic it ensures that there is no
+    // drift over time relative to the system clock.
+    virtual bool StartTimer(bool periodic, unsigned long time) = 0;
+
+    virtual bool StopTimer() = 0;
+
+    // Only implemented on Windows
+    // Returns 1 if a key has been pressed since last call to this function.
+    // -1 indicates failure
+    // 0 indicates no key has been pressed since last call
+    // TODO(hellner) this function does not seem to belong here
+    static int KeyPressed();
+};
+} // namespace webrtc
+
+#endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_EVENT_WRAPPER_H_