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   bool PostDelayedTask(const tracked_objects::Location& from_here,
  51                        const Closure& task,
  52                        TimeDelta delay) override;
  53   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
  54                                   const Closure& task,
  55                                   TimeDelta delay) override;
  56
  57   bool RunsTasksOnCurrentThread() const override;
  58
  59   const std::deque<TestPendingTask>& GetPendingTasks() const;
  60   bool HasPendingTask() const;
  61   base::TimeDelta NextPendingTaskDelay() const;
  62
  63   // Clears the queue of pending tasks without running them.
  64   void ClearPendingTasks();
  65
  66   // Runs each current pending task in order and clears the queue.
  67   // Any tasks posted by the tasks are not run.
  68   virtual void RunPendingTasks();
  69
  70   // Runs pending tasks until the queue is empty.
  71   void RunUntilIdle();
  72
  73  protected:
  74   ~TestSimpleTaskRunner() override;
  75
  76   std::deque<TestPendingTask> pending_tasks_;
  77   ThreadChecker thread_checker_;
  78
  79  private:
  80   DISALLOW_COPY_AND_ASSIGN(TestSimpleTaskRunner);
  81 };
  82
  83 }  // namespace base
  84
  85 #endif  // BASE_TEST_TEST_SIMPLE_TASK_RUNNER_H_