Fix pointer compare-and-swap on Windows.

webrtc/base/criticalsection_unittest.cc

 /*
  *  Copyright 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.
  */
 
 #include <set>
 #include <vector>
 
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/event.h"
 #include "webrtc/base/gunit.h"
+#include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/scopedptrcollection.h"
 #include "webrtc/base/thread.h"
 #include "webrtc/test/testsupport/gtest_disable.h"
 
 namespace rtc {
 
 namespace {
 
 const int kLongTime = 10000;  // 10 seconds
 const int kNumThreads = 16;
@@ skipping 186 matching lines @@
   EXPECT_EQ(1, AtomicOps::Increment(&value));
   EXPECT_EQ(1, value);
   EXPECT_EQ(2, AtomicOps::Increment(&value));
   EXPECT_EQ(2, value);
   EXPECT_EQ(1, AtomicOps::Decrement(&value));
   EXPECT_EQ(1, value);
   EXPECT_EQ(0, AtomicOps::Decrement(&value));
   EXPECT_EQ(0, value);
 }
 
+TEST(AtomicOpsTest, SimplePtr) {
+  class Foo {};
+  Foo* volatile foo = nullptr;
+  scoped_ptr<Foo> a(new Foo());
+  scoped_ptr<Foo> b(new Foo());
+  // Reading the initial value should work as expected.
+  EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == nullptr);
+  // Setting using compare and swap should work.
+  EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr(
+                  &foo, static_cast<Foo*>(nullptr), a.get()) == nullptr);
+  EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == a.get());
+  // Setting another value but with the wrong previous pointer should fail
+  // (remain a).
+  EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr(
+                  &foo, static_cast<Foo*>(nullptr), b.get()) == a.get());
+  EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == a.get());
+  // Replacing a with b should work.
+  EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr(&foo, a.get(), b.get()) ==
+              a.get());
+  EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == b.get());
+}
+
 TEST(AtomicOpsTest, Increment) {
   // Create and start lots of threads.
   AtomicOpRunner<IncrementOp, UniqueValueVerifier> runner(0);
   ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 
   // Release the hounds!
   EXPECT_TRUE(runner.Run());
   EXPECT_EQ(kOperationsToRun * kNumThreads, runner.shared_value());
@@ skipping 59 matching lines @@
   EXPECT_FALSE(cs.IsLocked());
   if (!cs.TryEnter())
     FAIL();
   EXPECT_TRUE(cs.IsLocked());
   cs.Leave();
   EXPECT_FALSE(cs.IsLocked());
 }
 #endif
 
 }  // namespace rtc