cc/trees/blocking_task_runner.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/trees/blocking_task_runner.h"
   6
   7 #include <utility>
   8
   9 #include "base/callback.h"
  10 #include "base/logging.h"
  11 #include "base/message_loop/message_loop_proxy.h"
  12
  13 namespace cc {
  14
  15 // static
  16 scoped_ptr<BlockingTaskRunner> BlockingTaskRunner::Create(
  17     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
  18   return make_scoped_ptr(new BlockingTaskRunner(task_runner));
  19 }
  20
  21 BlockingTaskRunner::BlockingTaskRunner(
  22     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
  23     : thread_id_(base::PlatformThread::CurrentId()),
  24       task_runner_(task_runner),
  25       capture_(0) {
  26 }
  27
  28 BlockingTaskRunner::~BlockingTaskRunner() {}
  29
  30 bool BlockingTaskRunner::BelongsToCurrentThread() {
  31   return base::PlatformThread::CurrentId() == thread_id_;
  32 }
  33
  34 bool BlockingTaskRunner::PostTask(const tracked_objects::Location& from_here,
  35                                   const base::Closure& task) {
  36   base::AutoLock lock(lock_);
  37   DCHECK(task_runner_.get() || capture_);
  38   if (!capture_)
  39     return task_runner_->PostTask(from_here, task);
  40   captured_tasks_.push_back(task);
  41   return true;
  42 }
  43
  44 void BlockingTaskRunner::SetCapture(bool capture) {
  45   DCHECK(BelongsToCurrentThread());
  46
  47   std::vector<base::Closure> tasks;
  48
  49   {
  50     base::AutoLock lock(lock_);
  51     capture_ += capture ? 1 : -1;
  52     DCHECK_GE(capture_, 0);
  53
  54     if (capture_)
  55       return;
  56
  57     // We're done capturing, so grab all the captured tasks and run them.
  58     tasks.swap(captured_tasks_);
  59   }
  60   for (size_t i = 0; i < tasks.size(); ++i)
  61     tasks[i].Run();
  62 }
  63
  64 BlockingTaskRunner::CapturePostTasks::CapturePostTasks(
  65     BlockingTaskRunner* blocking_runner)
  66     : blocking_runner_(blocking_runner) {
  67   blocking_runner_->SetCapture(true);
  68 }
  69
  70 BlockingTaskRunner::CapturePostTasks::~CapturePostTasks() {
  71   blocking_runner_->SetCapture(false);
  72 }
  73
  74 }  // namespace cc