/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "gtest/gtest.h"

#include "CopyOnWrite.h"

using namespace mozilla;

using namespace mozilla::image;

struct ValueStats

{

  int32_t mCopies = 0;

  int32_t mFrees = 0;

  int32_t mCalls = 0;

  int32_t mConstCalls = 0;

  int32_t mSerial = 0;

};

struct Value

{

  NS_INLINE_DECL_REFCOUNTING(Value)

  explicit Value(ValueStats& aStats)

    : mStats(aStats)

    , mSerial(mStats.mSerial++)

  { }

  Value(const Value& aOther)

    : mStats(aOther.mStats)

    , mSerial(mStats.mSerial++)

  {

    mStats.mCopies++;

  }

  void Go() { mStats.mCalls++; }

  void Go() const { mStats.mConstCalls++; }

  int32_t Serial() const { return mSerial; }

protected:

  ~Value() { mStats.mFrees++; }

private:

  ValueStats& mStats;

  int32_t mSerial;

};

TEST(ImageCopyOnWrite, Read)

{

  ValueStats stats;

  {

    CopyOnWrite<Value> cow(new Value(stats));

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_TRUE(cow.CanRead());

    cow.Read([&](const Value* aValue) {

      EXPECT_EQ(0, stats.mCopies);

      EXPECT_EQ(0, stats.mFrees);

      EXPECT_EQ(0, aValue->Serial());

      EXPECT_TRUE(cow.CanRead());

      EXPECT_TRUE(cow.CanWrite());

      aValue->Go();

      EXPECT_EQ(0, stats.mCalls);

      EXPECT_EQ(1, stats.mConstCalls);

    });

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_EQ(0, stats.mCalls);

    EXPECT_EQ(1, stats.mConstCalls);

  }

  EXPECT_EQ(0, stats.mCopies);

  EXPECT_EQ(1, stats.mFrees);

}

TEST(ImageCopyOnWrite, RecursiveRead)

{

  ValueStats stats;

  {

    CopyOnWrite<Value> cow(new Value(stats));

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_TRUE(cow.CanRead());

    cow.Read([&](const Value* aValue) {

      EXPECT_EQ(0, stats.mCopies);

      EXPECT_EQ(0, stats.mFrees);

      EXPECT_EQ(0, aValue->Serial());

      EXPECT_TRUE(cow.CanRead());

      EXPECT_TRUE(cow.CanWrite());

      // Make sure that Read() inside a Read() succeeds.

      cow.Read([&](const Value* aValue) {

        EXPECT_EQ(0, stats.mCopies);

        EXPECT_EQ(0, stats.mFrees);

        EXPECT_EQ(0, aValue->Serial());

        EXPECT_TRUE(cow.CanRead());

        EXPECT_TRUE(cow.CanWrite());

        aValue->Go();

        EXPECT_EQ(0, stats.mCalls);

        EXPECT_EQ(1, stats.mConstCalls);

      }, []() {

        // This gets called if we can't read. We shouldn't get here.

        EXPECT_TRUE(false);

      });

    });

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_EQ(0, stats.mCalls);

    EXPECT_EQ(1, stats.mConstCalls);

  }

  EXPECT_EQ(0, stats.mCopies);

  EXPECT_EQ(1, stats.mFrees);

}

TEST(ImageCopyOnWrite, Write)

{

  ValueStats stats;

  {

    CopyOnWrite<Value> cow(new Value(stats));

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_TRUE(cow.CanRead());

    EXPECT_TRUE(cow.CanWrite());

    cow.Write([&](Value* aValue) {

      EXPECT_EQ(0, stats.mCopies);

      EXPECT_EQ(0, stats.mFrees);

      EXPECT_EQ(0, aValue->Serial());

      EXPECT_TRUE(!cow.CanRead());

      EXPECT_TRUE(!cow.CanWrite());

      aValue->Go();

      EXPECT_EQ(1, stats.mCalls);

      EXPECT_EQ(0, stats.mConstCalls);

    });

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_EQ(1, stats.mCalls);

    EXPECT_EQ(0, stats.mConstCalls);

  }

  EXPECT_EQ(0, stats.mCopies);

  EXPECT_EQ(1, stats.mFrees);

}

TEST(ImageCopyOnWrite, WriteRecursive)

{

  ValueStats stats;

  {

    CopyOnWrite<Value> cow(new Value(stats));

    EXPECT_EQ(0, stats.mCopies);

    EXPECT_EQ(0, stats.mFrees);

    EXPECT_TRUE(cow.CanRead());

    EXPECT_TRUE(cow.CanWrite());

    cow.Read([&](const Value* aValue) {

      EXPECT_EQ(0, stats.mCopies);

      EXPECT_EQ(0, stats.mFrees);

      EXPECT_EQ(0, aValue->Serial());

      EXPECT_TRUE(cow.CanRead());

      EXPECT_TRUE(cow.CanWrite());

      // Make sure Write() inside a Read() succeeds.

      cow.Write([&](Value* aValue) {

        EXPECT_EQ(1, stats.mCopies);

        EXPECT_EQ(0, stats.mFrees);

        EXPECT_EQ(1, aValue->Serial());

        EXPECT_TRUE(!cow.CanRead());

        EXPECT_TRUE(!cow.CanWrite());

        aValue->Go();

        EXPECT_EQ(1, stats.mCalls);

        EXPECT_EQ(0, stats.mConstCalls);

        // Make sure Read() inside a Write() fails.

        cow.Read([](const Value* aValue) {

          // This gets called if we can read. We shouldn't get here.

          EXPECT_TRUE(false);

        }, []() {

          // This gets called if we can't read. We *should* get here.

          EXPECT_TRUE(true);

        });

        // Make sure Write() inside a Write() fails.

        cow.Write([](Value* aValue) {

          // This gets called if we can write. We shouldn't get here.

          EXPECT_TRUE(false);

        }, []() {

          // This gets called if we can't write. We *should* get here.

          EXPECT_TRUE(true);

        });

      }, []() {

        // This gets called if we can't write. We shouldn't get here.

        EXPECT_TRUE(false);

      });

      aValue->Go();

      EXPECT_EQ(1, stats.mCopies);

      EXPECT_EQ(0, stats.mFrees);

      EXPECT_EQ(1, stats.mCalls);

      EXPECT_EQ(1, stats.mConstCalls);

    });

    EXPECT_EQ(1, stats.mCopies);

    EXPECT_EQ(1, stats.mFrees);

    EXPECT_EQ(1, stats.mCalls);

    EXPECT_EQ(1, stats.mConstCalls);

  }

  EXPECT_EQ(1, stats.mCopies);

  EXPECT_EQ(2, stats.mFrees);

}