third_party/WebKit/public/platform/WebThread.h

   1 /*
   2  * Copyright (C) 2011 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  17  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  20  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  21  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25 #ifndef WebThread_h
  26 #define WebThread_h
  27
  28 #include "WebCommon.h"
  29 #include <stdint.h>
  30
  31 namespace blink {
  32 class WebScheduler;
  33 class WebTaskRunner;
  34 class WebTraceLocation;
  35
  36 // Always an integer value.
  37 typedef uintptr_t PlatformThreadId;
  38
  39 // Provides an interface to an embedder-defined thread implementation.
  40 //
  41 // Deleting the thread blocks until all pending, non-delayed tasks have been
  42 // run.
  43 class BLINK_PLATFORM_EXPORT WebThread {
  44 public:
  45     // An IdleTask is passed a deadline in CLOCK_MONOTONIC seconds and is
  46     // expected to complete before this deadline.
  47     class IdleTask {
  48     public:
  49         virtual ~IdleTask() { }
  50         virtual void run(double deadlineSeconds) = 0;
  51     };
  52
  53     class BLINK_PLATFORM_EXPORT TaskObserver {
  54     public:
  55         virtual ~TaskObserver() { }
  56         virtual void willProcessTask() = 0;
  57         virtual void didProcessTask() = 0;
  58     };
  59
  60
  61     // Returns a WebTaskRunner bound to the underlying scheduler's default task queue.
  62     virtual WebTaskRunner* taskRunner() { return nullptr; }
  63
  64     virtual bool isCurrentThread() const = 0;
  65     virtual PlatformThreadId threadId() const { return 0; }
  66
  67     virtual void addTaskObserver(TaskObserver*) { }
  68     virtual void removeTaskObserver(TaskObserver*) { }
  69
  70     // Returns the scheduler associated with the thread.
  71     virtual WebScheduler* scheduler() const = 0;
  72
  73     virtual ~WebThread() { }
  74 };
  75
  76 } // namespace blink
  77
  78 #endif