/*
 * Copyright (C) 2013 Google Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "platform/LifecycleNotifier.h"
#include "platform/LifecycleObserver.h"
#include "platform/heap/Handle.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace blink {

class TestingObserver;

class DummyContext final
    : public GarbageCollectedFinalized<DummyContext>,
      public LifecycleNotifier<DummyContext, TestingObserver> {
  USING_GARBAGE_COLLECTED_MIXIN(DummyContext);

 public:
  static DummyContext* create() { return new DummyContext; }

  DEFINE_INLINE_TRACE() {
    LifecycleNotifier<DummyContext, TestingObserver>::trace(visitor);
  }
};

class TestingObserver final
    : public GarbageCollected<TestingObserver>,
      public LifecycleObserver<DummyContext, TestingObserver> {
  USING_GARBAGE_COLLECTED_MIXIN(TestingObserver);

 public:
  static TestingObserver* create(DummyContext* context) {
    return new TestingObserver(context);
  }

  void contextDestroyed() override {
    LifecycleObserver::contextDestroyed();
    if (m_observerToRemoveOnDestruct) {
      lifecycleContext()->removeObserver(m_observerToRemoveOnDestruct);
      m_observerToRemoveOnDestruct.clear();
    }
    m_contextDestroyedCalled = true;
  }

  DEFINE_INLINE_TRACE() {
    visitor->trace(m_observerToRemoveOnDestruct);
    LifecycleObserver::trace(visitor);
  }

  void unobserve() { setContext(nullptr); }

  void setObserverToRemoveAndDestroy(
      TestingObserver* observerToRemoveOnDestruct) {
    ASSERT(!m_observerToRemoveOnDestruct);
    m_observerToRemoveOnDestruct = observerToRemoveOnDestruct;
  }

  TestingObserver* innerObserver() const {
    return m_observerToRemoveOnDestruct;
  }
  bool contextDestroyedCalled() const { return m_contextDestroyedCalled; }

 private:
  explicit TestingObserver(DummyContext* context)
      : LifecycleObserver(context), m_contextDestroyedCalled(false) {}

  Member<TestingObserver> m_observerToRemoveOnDestruct;
  bool m_contextDestroyedCalled;
};

TEST(LifecycleContextTest, shouldObserveContextDestroyed) {
  DummyContext* context = DummyContext::create();
  Persistent<TestingObserver> observer = TestingObserver::create(context);

  EXPECT_EQ(observer->lifecycleContext(), context);
  EXPECT_FALSE(observer->contextDestroyedCalled());
  context->notifyContextDestroyed();
  context = nullptr;
  ThreadState::current()->collectAllGarbage();
  EXPECT_EQ(observer->lifecycleContext(), static_cast<DummyContext*>(0));
  EXPECT_TRUE(observer->contextDestroyedCalled());
}

TEST(LifecycleContextTest, shouldNotObserveContextDestroyedIfUnobserve) {
  DummyContext* context = DummyContext::create();
  Persistent<TestingObserver> observer = TestingObserver::create(context);
  observer->unobserve();
  context->notifyContextDestroyed();
  context = nullptr;
  ThreadState::current()->collectAllGarbage();
  EXPECT_EQ(observer->lifecycleContext(), static_cast<DummyContext*>(0));
  EXPECT_FALSE(observer->contextDestroyedCalled());
}

TEST(LifecycleContextTest, observerRemovedDuringNotifyDestroyed) {
  DummyContext* context = DummyContext::create();
  Persistent<TestingObserver> observer = TestingObserver::create(context);
  TestingObserver* innerObserver = TestingObserver::create(context);
  // Attach the observer to the other. When 'observer' is notified
  // of destruction, it will remove & destroy 'innerObserver'.
  observer->setObserverToRemoveAndDestroy(innerObserver);

  EXPECT_EQ(observer->lifecycleContext(), context);
  EXPECT_EQ(observer->innerObserver()->lifecycleContext(), context);
  EXPECT_FALSE(observer->contextDestroyedCalled());
  EXPECT_FALSE(observer->innerObserver()->contextDestroyedCalled());

  context->notifyContextDestroyed();
  EXPECT_EQ(observer->innerObserver(), nullptr);
  context = nullptr;
  ThreadState::current()->collectAllGarbage();
  EXPECT_EQ(observer->lifecycleContext(), static_cast<DummyContext*>(0));
  EXPECT_TRUE(observer->contextDestroyedCalled());
}

}  // namespace blink