Add a Clock and TickClock interface for mocking out time

Add DefaultClock and DefaultTickClock implementations.

Add SimpleTestClock and SimpleTestTickClock implementations for test.

Port some classes in sync/ and media/ to use SimpleTest{,Tick}Clock.

BUG=166469

Review URL: https://codereview.chromium.org/11607003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@183865 0039d316-1c4b-4281-b951-d872f2087c98

15 files changed, 325 insertions, 0 deletions

diff --git a/base/base.gyp b/base/base.gyp
index 2c1ecc7..7c63ec2 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -834,6 +834,10 @@
         'test/scoped_path_override.h',
         'test/sequenced_task_runner_test_template.cc',
         'test/sequenced_task_runner_test_template.h',
+        'test/simple_test_clock.cc',
+        'test/simple_test_clock.h',
+        'test/simple_test_tick_clock.cc',
+        'test/simple_test_tick_clock.h',
         'test/task_runner_test_template.cc',
         'test/task_runner_test_template.h',
         'test/test_file_util.h',
diff --git a/base/base.gypi b/base/base.gypi
index 9f588c8..7cad42a 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -491,6 +491,15 @@
           'threading/worker_pool_posix.cc',
           'threading/worker_pool_posix.h',
           'threading/worker_pool_win.cc',
+          'time/clock.cc',
+          'time/clock.h',
+          'time/default_clock.cc',
+          'time/default_clock.h',
+          'time/default_tick_clock.cc',
+          'time/default_tick_clock.h',
+          'time/tick_clock.cc',
+          'time/tick_clock.h',
+          # TODO(akalin): Move time* into time/.
           'time.cc',
           'time.h',
           'time_mac.cc',
diff --git a/base/test/mock_time_provider.h b/base/test/mock_time_provider.h
index 81240f7..b493209 100644
--- a/base/test/mock_time_provider.h
+++ b/base/test/mock_time_provider.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// TODO(akalin): Change all users of this class to use SimpleTestClock
+// or SimpleTestTickClock and remove this class.
+
 // A helper class used to mock out calls to the static method base::Time::Now.
 //
 // Example usage:
diff --git a/base/test/simple_test_clock.cc b/base/test/simple_test_clock.cc
new file mode 100644
index 0000000..3bd6080
--- /dev/null
+++ b/base/test/simple_test_clock.cc
@@ -0,0 +1,23 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/test/simple_test_clock.h"
+
+namespace base {
+
+SimpleTestClock::SimpleTestClock() {}
+
+SimpleTestClock::~SimpleTestClock() {}
+
+Time SimpleTestClock::Now() {
+  AutoLock lock(lock_);
+  return now_;
+}
+
+void SimpleTestClock::Advance(TimeDelta delta) {
+  AutoLock lock(lock_);
+  now_ += delta;
+}
+
+}  // namespace base
diff --git a/base/test/simple_test_clock.h b/base/test/simple_test_clock.h
new file mode 100644
index 0000000..a83312f
--- /dev/null
+++ b/base/test/simple_test_clock.h
@@ -0,0 +1,39 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_SIMPLE_TEST_CLOCK_H_
+#define BASE_SIMPLE_TEST_CLOCK_H_
+
+#include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
+#include "base/time.h"
+#include "base/time/clock.h"
+
+namespace base {
+
+// SimpleTestClock is a Clock implementation that gives control over
+// the returned Time objects.  All methods can be called from any
+// thread.
+class SimpleTestClock : public Clock {
+ public:
+  // Starts off with a clock set to Time().
+  SimpleTestClock();
+  virtual ~SimpleTestClock();
+
+  virtual Time Now() OVERRIDE;
+
+  // Sets the current time forward by |delta|.  Safe to call from any
+  // thread.
+  void Advance(TimeDelta delta);
+
+ private:
+  // Protects |now_|.
+  Lock lock_;
+
+  Time now_;
+};
+
+}  // namespace base
+
+#endif  // BASE_SIMPLE_TEST_CLOCK_H_
diff --git a/base/test/simple_test_tick_clock.cc b/base/test/simple_test_tick_clock.cc
new file mode 100644
index 0000000..1b4696f
--- /dev/null
+++ b/base/test/simple_test_tick_clock.cc
@@ -0,0 +1,26 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/test/simple_test_tick_clock.h"
+
+#include "base/logging.h"
+
+namespace base {
+
+SimpleTestTickClock::SimpleTestTickClock() {}
+
+SimpleTestTickClock::~SimpleTestTickClock() {}
+
+TimeTicks SimpleTestTickClock::NowTicks() {
+  AutoLock lock(lock_);
+  return now_ticks_;
+}
+
+void SimpleTestTickClock::Advance(TimeDelta delta) {
+  AutoLock lock(lock_);
+  DCHECK(delta >= TimeDelta());
+  now_ticks_ += delta;
+}
+
+}  // namespace base
diff --git a/base/test/simple_test_tick_clock.h b/base/test/simple_test_tick_clock.h
new file mode 100644
index 0000000..c53301b
--- /dev/null
+++ b/base/test/simple_test_tick_clock.h
@@ -0,0 +1,39 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_SIMPLE_TEST_TICK_CLOCK_H_
+#define BASE_SIMPLE_TEST_TICK_CLOCK_H_
+
+#include "base/compiler_specific.h"
+#include "base/synchronization/lock.h"
+#include "base/time.h"
+#include "base/time/tick_clock.h"
+
+namespace base {
+
+// SimpleTestTickClock is a TickClock implementation that gives
+// control over the returned TimeTicks objects.  All methods can be
+// called from any thread.
+class SimpleTestTickClock : public TickClock {
+ public:
+  // Starts off with a clock set to TimeTicks().
+  SimpleTestTickClock();
+  virtual ~SimpleTestTickClock();
+
+  virtual TimeTicks NowTicks() OVERRIDE;
+
+  // Sets the current time forward by |delta|.  Safe to call from any
+  // thread.
+  void Advance(TimeDelta delta);
+
+ private:
+  // Protects |now_ticks_|.
+  Lock lock_;
+
+  TimeTicks now_ticks_;
+};
+
+}  // namespace base
+
+#endif  // BASE_SIMPLE_TEST_TICK_CLOCK_H_
diff --git a/base/time/clock.cc b/base/time/clock.cc
new file mode 100644
index 0000000..34dc37e
--- /dev/null
+++ b/base/time/clock.cc
@@ -0,0 +1,11 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/time/clock.h"
+
+namespace base {
+
+Clock::~Clock() {}
+
+}  // namespace base
diff --git a/base/time/clock.h b/base/time/clock.h
new file mode 100644
index 0000000..9fef254
--- /dev/null
+++ b/base/time/clock.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_CLOCK_H_
+#define BASE_CLOCK_H_
+
+#include "base/base_export.h"
+#include "base/time.h"
+
+namespace base {
+
+// A Clock is an interface for objects that vend Times.  It is
+// intended to be able to test the behavior of classes with respect to
+// time.
+//
+// See DefaultClock (base/default_clock.h) for the default
+// implementation that simply uses Time::Now().
+//
+// (An implementation that uses Time::SystemTime() should be added as
+// needed.)
+//
+// See SimpleTestClock (base/test/simple_test_clock.h) for a simple
+// test implementation.
+//
+// See TickClock (base/tick_clock.h) for the equivalent interface for
+// TimeTicks.
+class BASE_EXPORT Clock {
+ public:
+  virtual ~Clock();
+
+  // Now() must be safe to call from any thread.  The caller cannot
+  // make any ordering assumptions about the returned Time.  For
+  // example, the system clock may change to an earlier time.
+  virtual Time Now() = 0;
+};
+
+}  // namespace base
+
+#endif  // BASE_CLOCK_H_
diff --git a/base/time/default_clock.cc b/base/time/default_clock.cc
new file mode 100644
index 0000000..5f70114
--- /dev/null
+++ b/base/time/default_clock.cc
@@ -0,0 +1,15 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/time/default_clock.h"
+
+namespace base {
+
+DefaultClock::~DefaultClock() {}
+
+Time DefaultClock::Now() {
+  return Time::Now();
+}
+
+}  // namespace base
diff --git a/base/time/default_clock.h b/base/time/default_clock.h
new file mode 100644
index 0000000..2022d5c
--- /dev/null
+++ b/base/time/default_clock.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_DEFAULT_CLOCK_H_
+#define BASE_DEFAULT_CLOCK_H_
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/time/clock.h"
+
+namespace base {
+
+// DefaultClock is a Clock implementation that uses Time::Now().
+class BASE_EXPORT DefaultClock : public Clock {
+ public:
+  virtual ~DefaultClock();
+
+  // Simply returns Time::Now().
+  virtual Time Now() OVERRIDE;
+};
+
+}  // namespace base
+
+#endif  // BASE_DEFAULT_CLOCK_H_
diff --git a/base/time/default_tick_clock.cc b/base/time/default_tick_clock.cc
new file mode 100644
index 0000000..ce62fcc
--- /dev/null
+++ b/base/time/default_tick_clock.cc
@@ -0,0 +1,15 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/time/default_tick_clock.h"
+
+namespace base {
+
+DefaultTickClock::~DefaultTickClock() {}
+
+TimeTicks DefaultTickClock::NowTicks() {
+  return TimeTicks::Now();
+}
+
+}  // namespace base
diff --git a/base/time/default_tick_clock.h b/base/time/default_tick_clock.h
new file mode 100644
index 0000000..553a8d2
--- /dev/null
+++ b/base/time/default_tick_clock.h
@@ -0,0 +1,25 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_DEFAULT_TICK_CLOCK_H_
+#define BASE_DEFAULT_TICK_CLOCK_H_
+
+#include "base/base_export.h"
+#include "base/compiler_specific.h"
+#include "base/time/tick_clock.h"
+
+namespace base {
+
+// DefaultClock is a Clock implementation that uses TimeTicks::Now().
+class BASE_EXPORT DefaultTickClock : public TickClock {
+ public:
+  virtual ~DefaultTickClock();
+
+  // Simply returns TimeTicks::Now().
+  virtual TimeTicks NowTicks() OVERRIDE;
+};
+
+}  // namespace base
+
+#endif  // BASE_DEFAULT_CLOCK_H_
diff --git a/base/time/tick_clock.cc b/base/time/tick_clock.cc
new file mode 100644
index 0000000..495805c
--- /dev/null
+++ b/base/time/tick_clock.cc
@@ -0,0 +1,11 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/time/tick_clock.h"
+
+namespace base {
+
+TickClock::~TickClock() {}
+
+}  // namespace base
diff --git a/base/time/tick_clock.h b/base/time/tick_clock.h
new file mode 100644
index 0000000..396e0c9
--- /dev/null
+++ b/base/time/tick_clock.h
@@ -0,0 +1,40 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_TICK_CLOCK_H_
+#define BASE_TICK_CLOCK_H_
+
+#include "base/base_export.h"
+#include "base/time.h"
+
+namespace base {
+
+// A TickClock is an interface for objects that vend TimeTicks.  It is
+// intended to be able to test the behavior of classes with respect to
+// non-decreasing time.
+//
+// See DefaultTickClock (base/default_tick_clock.h) for the default
+// implementation that simply uses TimeTicks::Now().
+//
+// (Other implementations that use TimeTicks::HighResNow() or
+// TimeTicks::NowFromSystemTime() should be added as needed.)
+//
+// See SimpleTestTickClock (base/test/simple_test_tick_clock.h) for a
+// simple test implementation.
+//
+// See Clock (base/clock.h) for the equivalent interface for Times.
+class BASE_EXPORT TickClock {
+ public:
+  virtual ~TickClock();
+
+  // NowTicks() must be safe to call from any thread.  The caller may
+  // assume that NowTicks() is monotonic (but not strictly monotonic).
+  // In other words, the returned TimeTicks will never decrease with
+  // time, although they might "stand still".
+  virtual TimeTicks NowTicks() = 0;
+};
+
+}  // namespace base
+
+#endif  // BASE_TICK_CLOCK_H_