Importing ThreadChecker class from Chromium
The ThreadChecker class is imported/re-implemented from Chromium.
The implementation is changed to depend on WebRTC primitives.
R=andrew@webrtc.org, henrike@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/21649004
git-svn-id: http://webrtc.googlecode.com/svn/trunk@6446 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/base/base.gyp b/webrtc/base/base.gyp
index 94b9637..5cb1fd9 100644
--- a/webrtc/base/base.gyp
+++ b/webrtc/base/base.gyp
@@ -268,6 +268,9 @@
'testclient.h',
'thread.cc',
'thread.h',
+ 'thread_checker.h',
+ 'thread_checker_impl.cc',
+ 'thread_checker_impl.h',
'timeutils.cc',
'timeutils.h',
'timing.cc',
diff --git a/webrtc/base/base_tests.gyp b/webrtc/base/base_tests.gyp
index b5ab23f..c5cc7b8 100644
--- a/webrtc/base/base_tests.gyp
+++ b/webrtc/base/base_tests.gyp
@@ -96,6 +96,7 @@
# 'systeminfo_unittest.cc',
'task_unittest.cc',
'testclient_unittest.cc',
+ 'thread_checker_unittest.cc',
'thread_unittest.cc',
'timeutils_unittest.cc',
'urlencode_unittest.cc',
diff --git a/webrtc/base/thread_checker.h b/webrtc/base/thread_checker.h
new file mode 100644
index 0000000..eee9315
--- /dev/null
+++ b/webrtc/base/thread_checker.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Borrowed from Chromium's src/base/threading/thread_checker.h.
+
+#ifndef WEBRTC_BASE_THREAD_CHECKER_H_
+#define WEBRTC_BASE_THREAD_CHECKER_H_
+
+// Apart from debug builds, we also enable the thread checker in
+// builds with DCHECK_ALWAYS_ON so that trybots and waterfall bots
+// with this define will get the same level of thread checking as
+// debug bots.
+//
+// Note that this does not perfectly match situations where DCHECK is
+// enabled. For example a non-official release build may have
+// DCHECK_ALWAYS_ON undefined (and therefore ThreadChecker would be
+// disabled) but have DCHECKs enabled at runtime.
+#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
+#define ENABLE_THREAD_CHECKER 1
+#else
+#define ENABLE_THREAD_CHECKER 0
+#endif
+
+#include "webrtc/base/thread_checker_impl.h"
+
+namespace rtc {
+
+// Do nothing implementation, for use in release mode.
+//
+// Note: You should almost always use the ThreadChecker class to get the
+// right version for your build configuration.
+class ThreadCheckerDoNothing {
+ public:
+ bool CalledOnValidThread() const {
+ return true;
+ }
+
+ void DetachFromThread() {}
+};
+
+// ThreadChecker is a helper class used to help verify that some methods of a
+// class are called from the same thread. It provides identical functionality to
+// base::NonThreadSafe, but it is meant to be held as a member variable, rather
+// than inherited from base::NonThreadSafe.
+//
+// While inheriting from base::NonThreadSafe may give a clear indication about
+// the thread-safety of a class, it may also lead to violations of the style
+// guide with regard to multiple inheritance. The choice between having a
+// ThreadChecker member and inheriting from base::NonThreadSafe should be based
+// on whether:
+// - Derived classes need to know the thread they belong to, as opposed to
+// having that functionality fully encapsulated in the base class.
+// - Derived classes should be able to reassign the base class to another
+// thread, via DetachFromThread.
+//
+// If neither of these are true, then having a ThreadChecker member and calling
+// CalledOnValidThread is the preferable solution.
+//
+// Example:
+// class MyClass {
+// public:
+// void Foo() {
+// DCHECK(thread_checker_.CalledOnValidThread());
+// ... (do stuff) ...
+// }
+//
+// private:
+// ThreadChecker thread_checker_;
+// }
+//
+// In Release mode, CalledOnValidThread will always return true.
+#if ENABLE_THREAD_CHECKER
+class ThreadChecker : public ThreadCheckerImpl {
+};
+#else
+class ThreadChecker : public ThreadCheckerDoNothing {
+};
+#endif // ENABLE_THREAD_CHECKER
+
+#undef ENABLE_THREAD_CHECKER
+
+} // namespace rtc
+
+#endif // WEBRTC_BASE_THREAD_CHECKER_H_
diff --git a/webrtc/base/thread_checker_impl.cc b/webrtc/base/thread_checker_impl.cc
new file mode 100644
index 0000000..4a7455d
--- /dev/null
+++ b/webrtc/base/thread_checker_impl.cc
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Borrowed from Chromium's src/base/threading/thread_checker_impl.cc.
+
+#include "webrtc/base/thread_checker_impl.h"
+
+#include "webrtc/base/thread.h"
+
+namespace rtc {
+
+ThreadCheckerImpl::ThreadCheckerImpl()
+ : valid_thread_() {
+ EnsureThreadIdAssigned();
+}
+
+ThreadCheckerImpl::~ThreadCheckerImpl() {
+}
+
+bool ThreadCheckerImpl::CalledOnValidThread() const {
+ CritScope scoped_lock(&lock_);
+ EnsureThreadIdAssigned();
+ return valid_thread_->IsCurrent();
+}
+
+void ThreadCheckerImpl::DetachFromThread() {
+ CritScope scoped_lock(&lock_);
+ valid_thread_ = NULL;
+}
+
+void ThreadCheckerImpl::EnsureThreadIdAssigned() const {
+ if (!valid_thread_) {
+ valid_thread_ = Thread::Current();
+ }
+}
+
+} // namespace rtc
diff --git a/webrtc/base/thread_checker_impl.h b/webrtc/base/thread_checker_impl.h
new file mode 100644
index 0000000..1d776b5
--- /dev/null
+++ b/webrtc/base/thread_checker_impl.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Borrowed from Chromium's src/base/threading/thread_checker_impl.h.
+
+#ifndef WEBRTC_BASE_THREAD_CHECKER_IMPL_H_
+#define WEBRTC_BASE_THREAD_CHECKER_IMPL_H_
+
+#include "webrtc/base/criticalsection.h"
+
+namespace rtc {
+
+class Thread;
+
+// Real implementation of ThreadChecker, for use in debug mode, or
+// for temporary use in release mode (e.g. to CHECK on a threading issue
+// seen only in the wild).
+//
+// Note: You should almost always use the ThreadChecker class to get the
+// right version for your build configuration.
+class ThreadCheckerImpl {
+ public:
+ ThreadCheckerImpl();
+ ~ThreadCheckerImpl();
+
+ bool CalledOnValidThread() const;
+
+ // Changes the thread that is checked for in CalledOnValidThread. This may
+ // be useful when an object may be created on one thread and then used
+ // exclusively on another thread.
+ void DetachFromThread();
+
+ private:
+ void EnsureThreadIdAssigned() const;
+
+ mutable CriticalSection lock_;
+ // This is mutable so that CalledOnValidThread can set it.
+ // It's guarded by |lock_|.
+ mutable const Thread* valid_thread_;
+};
+
+} // namespace rtc
+
+#endif // WEBRTC_BASE_THREAD_CHECKER_IMPL_H_
diff --git a/webrtc/base/thread_checker_unittest.cc b/webrtc/base/thread_checker_unittest.cc
new file mode 100644
index 0000000..13c1da5
--- /dev/null
+++ b/webrtc/base/thread_checker_unittest.cc
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Borrowed from Chromium's src/base/threading/thread_checker_unittest.cc.
+
+#include <assert.h>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/base/thread_checker.h"
+#include "webrtc/base/scoped_ptr.h"
+
+// Duplicated from base/threading/thread_checker.h so that we can be
+// good citizens there and undef the macro.
+#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
+#define ENABLE_THREAD_CHECKER 1
+#else
+#define ENABLE_THREAD_CHECKER 0
+#endif
+
+namespace rtc {
+
+namespace {
+
+// Simple class to exercise the basics of ThreadChecker.
+// Both the destructor and DoStuff should verify that they were
+// called on the same thread as the constructor.
+class ThreadCheckerClass : public ThreadChecker {
+ public:
+ ThreadCheckerClass() {}
+
+ // Verifies that it was called on the same thread as the constructor.
+ void DoStuff() {
+ assert(CalledOnValidThread());
+ }
+
+ void DetachFromThread() {
+ ThreadChecker::DetachFromThread();
+ }
+
+ static void MethodOnDifferentThreadImpl();
+ static void DetachThenCallFromDifferentThreadImpl();
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(ThreadCheckerClass);
+};
+
+// Calls ThreadCheckerClass::DoStuff on another thread.
+class CallDoStuffOnThread : public Thread {
+ public:
+ explicit CallDoStuffOnThread(ThreadCheckerClass* thread_checker_class)
+ : Thread(),
+ thread_checker_class_(thread_checker_class) {
+ SetName("call_do_stuff_on_thread", NULL);
+ }
+
+ virtual void Run() OVERRIDE {
+ thread_checker_class_->DoStuff();
+ }
+
+ // New method. Needed since Thread::Join is protected, and it is called by
+ // the TEST.
+ void Join() {
+ Thread::Join();
+ }
+
+ private:
+ ThreadCheckerClass* thread_checker_class_;
+
+ DISALLOW_COPY_AND_ASSIGN(CallDoStuffOnThread);
+};
+
+// Deletes ThreadCheckerClass on a different thread.
+class DeleteThreadCheckerClassOnThread : public Thread {
+ public:
+ explicit DeleteThreadCheckerClassOnThread(
+ ThreadCheckerClass* thread_checker_class)
+ : Thread(),
+ thread_checker_class_(thread_checker_class) {
+ SetName("delete_thread_checker_class_on_thread", NULL);
+ }
+
+ virtual void Run() OVERRIDE {
+ thread_checker_class_.reset();
+ }
+
+ // New method. Needed since Thread::Join is protected, and it is called by
+ // the TEST.
+ void Join() {
+ Thread::Join();
+ }
+
+ private:
+ scoped_ptr<ThreadCheckerClass> thread_checker_class_;
+
+ DISALLOW_COPY_AND_ASSIGN(DeleteThreadCheckerClassOnThread);
+};
+
+} // namespace
+
+TEST(ThreadCheckerTest, CallsAllowedOnSameThread) {
+ scoped_ptr<ThreadCheckerClass> thread_checker_class(
+ new ThreadCheckerClass);
+
+ // Verify that DoStuff doesn't assert.
+ thread_checker_class->DoStuff();
+
+ // Verify that the destructor doesn't assert.
+ thread_checker_class.reset();
+}
+
+TEST(ThreadCheckerTest, DestructorAllowedOnDifferentThread) {
+ scoped_ptr<ThreadCheckerClass> thread_checker_class(
+ new ThreadCheckerClass);
+
+ // Verify that the destructor doesn't assert
+ // when called on a different thread.
+ DeleteThreadCheckerClassOnThread delete_on_thread(
+ thread_checker_class.release());
+
+ delete_on_thread.Start();
+ delete_on_thread.Join();
+}
+
+TEST(ThreadCheckerTest, DetachFromThread) {
+ scoped_ptr<ThreadCheckerClass> thread_checker_class(
+ new ThreadCheckerClass);
+
+ // Verify that DoStuff doesn't assert when called on a different thread after
+ // a call to DetachFromThread.
+ thread_checker_class->DetachFromThread();
+ CallDoStuffOnThread call_on_thread(thread_checker_class.get());
+
+ call_on_thread.Start();
+ call_on_thread.Join();
+}
+
+#if GTEST_HAS_DEATH_TEST || !ENABLE_THREAD_CHECKER
+
+void ThreadCheckerClass::MethodOnDifferentThreadImpl() {
+ scoped_ptr<ThreadCheckerClass> thread_checker_class(
+ new ThreadCheckerClass);
+
+ // DoStuff should assert in debug builds only when called on a
+ // different thread.
+ CallDoStuffOnThread call_on_thread(thread_checker_class.get());
+
+ call_on_thread.Start();
+ call_on_thread.Join();
+}
+
+#if ENABLE_THREAD_CHECKER
+TEST(ThreadCheckerDeathTest, MethodNotAllowedOnDifferentThreadInDebug) {
+ ASSERT_DEATH({
+ ThreadCheckerClass::MethodOnDifferentThreadImpl();
+ }, "");
+}
+#else
+TEST(ThreadCheckerTest, MethodAllowedOnDifferentThreadInRelease) {
+ ThreadCheckerClass::MethodOnDifferentThreadImpl();
+}
+#endif // ENABLE_THREAD_CHECKER
+
+void ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl() {
+ scoped_ptr<ThreadCheckerClass> thread_checker_class(
+ new ThreadCheckerClass);
+
+ // DoStuff doesn't assert when called on a different thread
+ // after a call to DetachFromThread.
+ thread_checker_class->DetachFromThread();
+ CallDoStuffOnThread call_on_thread(thread_checker_class.get());
+
+ call_on_thread.Start();
+ call_on_thread.Join();
+
+ // DoStuff should assert in debug builds only after moving to
+ // another thread.
+ thread_checker_class->DoStuff();
+}
+
+#if ENABLE_THREAD_CHECKER
+TEST(ThreadCheckerDeathTest, DetachFromThreadInDebug) {
+ ASSERT_DEATH({
+ ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl();
+ }, "");
+}
+#else
+TEST(ThreadCheckerTest, DetachFromThreadInRelease) {
+ ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl();
+}
+#endif // ENABLE_THREAD_CHECKER
+
+#endif // GTEST_HAS_DEATH_TEST || !ENABLE_THREAD_CHECKER
+
+// Just in case we ever get lumped together with other compilation units.
+#undef ENABLE_THREAD_CHECKER
+
+} // namespace rtc
