Add chrome to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 117 insertions, 0 deletions

diff --git a/chrome/common/worker_thread_ticker.h b/chrome/common/worker_thread_ticker.h
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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CHROME_COMMON_WORKER_THREAD_TICKER_H__
+#define CHROME_COMMON_WORKER_THREAD_TICKER_H__
+
+#include <windows.h>
+#include <atlbase.h>
+#include <vector>
+
+#include "base/lock.h"
+
+// This class provides the follwoing functionality:
+// It invokes a set of registered handlers at periodic intervals in
+// the context of an arbitrary worker thread.
+// This functionality is similar to a waitable timer except that the
+// timer in this case is a low-resolution timer (millisecond granularity)
+// and it does not require the caller to be in an alertable wait state.
+// The callbacks are invoked in the context of an arbitrary worker thread
+// from the system thread pool
+class WorkerThreadTicker {
+ public:
+  // This callback interface to be implemented by clients of this
+  // class
+  class Callback {
+   public:
+    // Gets invoked when the timer period is up
+    virtual void OnTick() = 0;
+  };
+
+  // tick_interval is the periodic interval in which to invoke the
+  // registered handlers
+  explicit WorkerThreadTicker(int tick_interval);
+
+  ~WorkerThreadTicker();
+
+  // Registers a callback handler interface
+  // tick_handler is the handler interface to register. The ownership of this
+  // object is not transferred to this class.
+  bool RegisterTickHandler(Callback *tick_handler);
+
+  // Unregisters a callback handler interface
+  // tick_handler is the handler interface to unregister
+  bool UnregisterTickHandler(Callback *tick_handler);
+
+  // Starts the ticker. Returns false if the ticker is already running
+  // or if the Start fails.
+  bool Start();
+  // Stops the ticker and waits for all callbacks. to be done. This method
+  // does not provide a way to stop without waiting for the callbacks to be
+  // done because this is inherently risky.
+  // Returns false is the ticker is not running
+  bool Stop();
+  bool IsRunning() const;
+
+  void set_tick_interval(int tick_interval) {
+    tick_interval_ = tick_interval;
+  }
+
+  int tick_interval() const {
+    return tick_interval_;
+  }
+
+ private:
+  // A list type that holds all registered callback interfaces
+  typedef std::vector<Callback*> TickHandlerListType;
+
+  // This is the callback function registered with the
+  // RegisterWaitForSingleObject API. It gets invoked in a system worker thread
+  // periodically at intervals of tick_interval_ miliiseconds
+  static void CALLBACK TickCallback(WorkerThreadTicker* this_ticker,
+                                    BOOLEAN timer_or_wait_fired);
+
+  // Helper that invokes all registered handlers
+  void InvokeHandlers();
+
+  // A dummy event to be used by the RegisterWaitForSingleObject API
+  CHandle dummy_event_;
+  // The wait handle returned by the RegisterWaitForSingleObject API
+  HANDLE wait_handle_;
+  // The interval at which the callbacks are to be invoked
+  int tick_interval_;
+  // Lock for the tick_handler_list_ list
+  Lock tick_handler_list_lock_;
+  // A list that holds all registered callback interfaces
+  TickHandlerListType tick_handler_list_;
+
+  DISALLOW_EVIL_CONSTRUCTORS(WorkerThreadTicker);
+};
+
+#endif  // CHROME_COMMON_WORKER_THREAD_TICKER_H__