base/test/test_simple_task_runner.h

   1 // Copyright (c) 2012 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 #ifndef BASE_TEST_TEST_SIMPLE_TASK_RUNNER_H_
   6 #define BASE_TEST_TEST_SIMPLE_TASK_RUNNER_H_
   7
   8 #include <deque>
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/single_thread_task_runner.h"
  13 #include "base/test/test_pending_task.h"
  14 #include "base/threading/thread_checker.h"
  15
  16 namespace base {
  17
  18 class TimeDelta;
  19
  20 // TestSimpleTaskRunner is a simple TaskRunner implementation that can
  21 // be used for testing.  It implements SingleThreadTaskRunner as that
  22 // interface implements SequencedTaskRunner, which in turn implements
  23 // TaskRunner, so TestSimpleTaskRunner can be passed in to a function
  24 // that accepts any *TaskRunner object.
  25 //
  26 // TestSimpleTaskRunner has the following properties which make it simple:
  27 //
  28 //   - It is non-thread safe; all member functions must be called on
  29 //     the same thread.
  30 //   - Tasks are simply stored in a queue in FIFO order, ignoring delay
  31 //     and nestability.
  32 //   - Tasks aren't guaranteed to be destroyed immediately after
  33 //     they're run.
  34 //
  35 // However, TestSimpleTaskRunner allows for reentrancy, in that it
  36 // handles the running of tasks that in turn call back into itself
  37 // (e.g., to post more tasks).
  38 //
  39 // If you need more complicated properties, consider using this class
  40 // as a template for writing a test TaskRunner implementation using
  41 // TestPendingTask.
  42 //
  43 // Note that, like any TaskRunner, TestSimpleTaskRunner is
  44 // ref-counted.
  45 class TestSimpleTaskRunner : public SingleThreadTaskRunner {
  46  public:
  47   TestSimpleTaskRunner();
  48
  49   // SingleThreadTaskRunner implementation.
  50   virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
  51                                const Closure& task,
  52                                TimeDelta delay) OVERRIDE;
  53   virtual bool PostNonNestableDelayedTask(
  54       const tracked_objects::Location& from_here,
  55       const Closure& task,
  56       TimeDelta delay) OVERRIDE;
  57
  58   virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
  59
  60   const std::deque<TestPendingTask>& GetPendingTasks() const;
  61   bool HasPendingTask() const;
  62   base::TimeDelta NextPendingTaskDelay() const;
  63
  64   // Clears the queue of pending tasks without running them.
  65   void ClearPendingTasks();
  66
  67   // Runs each current pending task in order and clears the queue.
  68   // Any tasks posted by the tasks are not run.
  69   virtual void RunPendingTasks();
  70
  71   // Runs pending tasks until the queue is empty.
  72   void RunUntilIdle();
  73
  74  protected:
  75   virtual ~TestSimpleTaskRunner();
  76
  77   std::deque<TestPendingTask> pending_tasks_;
  78   ThreadChecker thread_checker_;
  79
  80  private:
  81   DISALLOW_COPY_AND_ASSIGN(TestSimpleTaskRunner);
  82 };
  83
  84 }  // namespace base
  85
  86 #endif  // BASE_TEST_TEST_SIMPLE_TASK_RUNNER_H_