/*
 * Copyright (C) 2011 Apple 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 "wtf/Functional.h"

#include "testing/gtest/include/gtest/gtest.h"
#include "wtf/RefCounted.h"
#include "wtf/WeakPtr.h"
#include <utility>

namespace WTF {

class UnwrappedClass {
 public:
  explicit UnwrappedClass(int value) : m_value(value) {}

  int value() const { return m_value; }

 private:
  int m_value;
};

// This class must be wrapped in bind() and unwrapped in closure execution.
class ClassToBeWrapped {
  WTF_MAKE_NONCOPYABLE(ClassToBeWrapped);

 public:
  explicit ClassToBeWrapped(int value) : m_value(value) {}

  int value() const { return m_value; }

 private:
  int m_value;
};

class WrappedClass {
 public:
  WrappedClass(const ClassToBeWrapped& to_be_wrapped)
      : m_value(to_be_wrapped.value()) {}

  explicit WrappedClass(int value) : m_value(value) {}

  UnwrappedClass unwrap() const { return UnwrappedClass(m_value); }

 private:
  int m_value;
};

template <>
struct ParamStorageTraits<ClassToBeWrapped> {
  using StorageType = WrappedClass;
};

class HasWeakPtrSupport {
 public:
  HasWeakPtrSupport() : m_weakPtrFactory(this) {}

  WTF::WeakPtr<HasWeakPtrSupport> createWeakPtr() {
    return m_weakPtrFactory.createWeakPtr();
  }

  void revokeAll() { m_weakPtrFactory.revokeAll(); }

  void increment(int* counter) { ++*counter; }

 private:
  WTF::WeakPtrFactory<HasWeakPtrSupport> m_weakPtrFactory;
};

}  // namespace WTF

namespace base {

template <>
struct BindUnwrapTraits<WTF::WrappedClass> {
  static WTF::UnwrappedClass Unwrap(const WTF::WrappedClass& wrapped) {
    return wrapped.unwrap();
  }
};

}  // namespace base

namespace WTF {
namespace {

int returnFortyTwo() {
  return 42;
}

TEST(FunctionalTest, Basic) {
  std::unique_ptr<Function<int()>> returnFortyTwoFunction =
      bind(returnFortyTwo);
  EXPECT_EQ(42, (*returnFortyTwoFunction)());
}

int multiplyByTwo(int n) {
  return n * 2;
}

double multiplyByOneAndAHalf(double d) {
  return d * 1.5;
}

TEST(FunctionalTest, UnaryBind) {
  std::unique_ptr<Function<int()>> multiplyFourByTwoFunction =
      bind(multiplyByTwo, 4);
  EXPECT_EQ(8, (*multiplyFourByTwoFunction)());

  std::unique_ptr<Function<double()>> multiplyByOneAndAHalfFunction =
      bind(multiplyByOneAndAHalf, 3);
  EXPECT_EQ(4.5, (*multiplyByOneAndAHalfFunction)());
}

TEST(FunctionalTest, UnaryPartBind) {
  std::unique_ptr<Function<int(int)>> multiplyByTwoFunction =
      bind(multiplyByTwo);
  EXPECT_EQ(8, (*multiplyByTwoFunction)(4));

  std::unique_ptr<Function<double(double)>> multiplyByOneAndAHalfFunction =
      bind(multiplyByOneAndAHalf);
  EXPECT_EQ(4.5, (*multiplyByOneAndAHalfFunction)(3));
}

int multiply(int x, int y) {
  return x * y;
}

int subtract(int x, int y) {
  return x - y;
}

TEST(FunctionalTest, BinaryBind) {
  std::unique_ptr<Function<int()>> multiplyFourByTwoFunction =
      bind(multiply, 4, 2);
  EXPECT_EQ(8, (*multiplyFourByTwoFunction)());

  std::unique_ptr<Function<int()>> subtractTwoFromFourFunction =
      bind(subtract, 4, 2);
  EXPECT_EQ(2, (*subtractTwoFromFourFunction)());
}

TEST(FunctionalTest, BinaryPartBind) {
  std::unique_ptr<Function<int(int)>> multiplyFourFunction = bind(multiply, 4);
  EXPECT_EQ(8, (*multiplyFourFunction)(2));
  std::unique_ptr<Function<int(int, int)>> multiplyFunction = bind(multiply);
  EXPECT_EQ(8, (*multiplyFunction)(4, 2));

  std::unique_ptr<Function<int(int)>> subtractFromFourFunction =
      bind(subtract, 4);
  EXPECT_EQ(2, (*subtractFromFourFunction)(2));
  std::unique_ptr<Function<int(int, int)>> subtractFunction = bind(subtract);
  EXPECT_EQ(2, (*subtractFunction)(4, 2));
}

void sixArgFunc(int a, double b, char c, int* d, double* e, char* f) {
  *d = a;
  *e = b;
  *f = c;
}

void assertArgs(int actualInt,
                double actualDouble,
                char actualChar,
                int expectedInt,
                double expectedDouble,
                char expectedChar) {
  EXPECT_EQ(expectedInt, actualInt);
  EXPECT_EQ(expectedDouble, actualDouble);
  EXPECT_EQ(expectedChar, actualChar);
}

TEST(FunctionalTest, MultiPartBind) {
  int a = 0;
  double b = 0.5;
  char c = 'a';

  std::unique_ptr<Function<void(int, double, char, int*, double*, char*)>>
      unbound = bind(sixArgFunc);
  (*unbound)(1, 1.5, 'b', &a, &b, &c);
  assertArgs(a, b, c, 1, 1.5, 'b');

  std::unique_ptr<Function<void(double, char, int*, double*, char*)>> oneBound =
      bind(sixArgFunc, 2);
  (*oneBound)(2.5, 'c', &a, &b, &c);
  assertArgs(a, b, c, 2, 2.5, 'c');

  std::unique_ptr<Function<void(char, int*, double*, char*)>> twoBound =
      bind(sixArgFunc, 3, 3.5);
  (*twoBound)('d', &a, &b, &c);
  assertArgs(a, b, c, 3, 3.5, 'd');

  std::unique_ptr<Function<void(int*, double*, char*)>> threeBound =
      bind(sixArgFunc, 4, 4.5, 'e');
  (*threeBound)(&a, &b, &c);
  assertArgs(a, b, c, 4, 4.5, 'e');

  std::unique_ptr<Function<void(double*, char*)>> fourBound =
      bind(sixArgFunc, 5, 5.5, 'f', unretained(&a));
  (*fourBound)(&b, &c);
  assertArgs(a, b, c, 5, 5.5, 'f');

  std::unique_ptr<Function<void(char*)>> fiveBound =
      bind(sixArgFunc, 6, 6.5, 'g', unretained(&a), unretained(&b));
  (*fiveBound)(&c);
  assertArgs(a, b, c, 6, 6.5, 'g');

  std::unique_ptr<Function<void()>> sixBound = bind(
      sixArgFunc, 7, 7.5, 'h', unretained(&a), unretained(&b), unretained(&c));
  (*sixBound)();
  assertArgs(a, b, c, 7, 7.5, 'h');
}

class A {
 public:
  explicit A(int i) : m_i(i) {}

  int f() { return m_i; }
  int addF(int j) { return m_i + j; }
  virtual int overridden() { return 42; }

 private:
  int m_i;
};

class B : public A {
 public:
  explicit B(int i) : A(i) {}

  int f() { return A::f() + 1; }
  int addF(int j) { return A::addF(j) + 1; }
  int overridden() override { return 43; }
};

TEST(FunctionalTest, MemberFunctionBind) {
  A a(10);
  std::unique_ptr<Function<int()>> function1 = bind(&A::f, unretained(&a));
  EXPECT_EQ(10, (*function1)());

  std::unique_ptr<Function<int()>> function2 =
      bind(&A::addF, unretained(&a), 15);
  EXPECT_EQ(25, (*function2)());

  std::unique_ptr<Function<int()>> function3 =
      bind(&A::overridden, unretained(&a));
  EXPECT_EQ(42, (*function3)());
}

TEST(FunctionalTest, MemberFunctionBindWithSubclassPointer) {
  B b(10);
  std::unique_ptr<Function<int()>> function1 = bind(&A::f, unretained(&b));
  EXPECT_EQ(10, (*function1)());

  std::unique_ptr<Function<int()>> function2 =
      bind(&A::addF, unretained(&b), 15);
  EXPECT_EQ(25, (*function2)());

  std::unique_ptr<Function<int()>> function3 =
      bind(&A::overridden, unretained(&b));
  EXPECT_EQ(43, (*function3)());

  std::unique_ptr<Function<int()>> function4 = bind(&B::f, unretained(&b));
  EXPECT_EQ(11, (*function4)());

  std::unique_ptr<Function<int()>> function5 =
      bind(&B::addF, unretained(&b), 15);
  EXPECT_EQ(26, (*function5)());
}

TEST(FunctionalTest, MemberFunctionBindWithSubclassPointerWithCast) {
  B b(10);
  std::unique_ptr<Function<int()>> function1 =
      bind(&A::f, unretained(static_cast<A*>(&b)));
  EXPECT_EQ(10, (*function1)());

  std::unique_ptr<Function<int()>> function2 =
      bind(&A::addF, unretained(static_cast<A*>(&b)), 15);
  EXPECT_EQ(25, (*function2)());

  std::unique_ptr<Function<int()>> function3 =
      bind(&A::overridden, unretained(static_cast<A*>(&b)));
  EXPECT_EQ(43, (*function3)());
}

TEST(FunctionalTest, MemberFunctionPartBind) {
  A a(10);
  std::unique_ptr<Function<int(class A*)>> function1 = bind(&A::f);
  EXPECT_EQ(10, (*function1)(&a));

  std::unique_ptr<Function<int(class A*, int)>> unboundFunction2 =
      bind(&A::addF);
  EXPECT_EQ(25, (*unboundFunction2)(&a, 15));
  std::unique_ptr<Function<int(int)>> objectBoundFunction2 =
      bind(&A::addF, unretained(&a));
  EXPECT_EQ(25, (*objectBoundFunction2)(15));
}

TEST(FunctionalTest, MemberFunctionBindByUniquePtr) {
  std::unique_ptr<Function<int()>> function1 =
      WTF::bind(&A::f, makeUnique<A>(10));
  EXPECT_EQ(10, (*function1)());
}

TEST(FunctionalTest, MemberFunctionBindByPassedUniquePtr) {
  std::unique_ptr<Function<int()>> function1 =
      WTF::bind(&A::f, passed(makeUnique<A>(10)));
  EXPECT_EQ(10, (*function1)());
}

class Number : public RefCounted<Number> {
 public:
  static PassRefPtr<Number> create(int value) {
    return adoptRef(new Number(value));
  }

  ~Number() { m_value = 0; }

  int value() const { return m_value; }

 private:
  explicit Number(int value) : m_value(value) {}

  int m_value;
};

int multiplyNumberByTwo(Number* number) {
  return number->value() * 2;
}

TEST(FunctionalTest, RefCountedStorage) {
  RefPtr<Number> five = Number::create(5);
  EXPECT_EQ(1, five->refCount());
  std::unique_ptr<Function<int()>> multiplyFiveByTwoFunction =
      bind(multiplyNumberByTwo, five);
  EXPECT_EQ(2, five->refCount());
  EXPECT_EQ(10, (*multiplyFiveByTwoFunction)());
  EXPECT_EQ(2, five->refCount());

  std::unique_ptr<Function<int()>> multiplyFourByTwoFunction =
      bind(multiplyNumberByTwo, Number::create(4));
  EXPECT_EQ(8, (*multiplyFourByTwoFunction)());

  RefPtr<Number> six = Number::create(6);
  std::unique_ptr<Function<int()>> multiplySixByTwoFunction =
      bind(multiplyNumberByTwo, six.release());
  EXPECT_FALSE(six);
  EXPECT_EQ(12, (*multiplySixByTwoFunction)());
}

TEST(FunctionalTest, UnretainedWithRefCounted) {
  RefPtr<Number> five = Number::create(5);
  EXPECT_EQ(1, five->refCount());
  std::unique_ptr<Function<int()>> multiplyFiveByTwoFunction =
      bind(multiplyNumberByTwo, unretained(five.get()));
  EXPECT_EQ(1, five->refCount());
  EXPECT_EQ(10, (*multiplyFiveByTwoFunction)());
  EXPECT_EQ(1, five->refCount());
}

int processUnwrappedClass(const UnwrappedClass& u, int v) {
  return u.value() * v;
}

// Tests that:
// - ParamStorageTraits's wrap()/unwrap() are called, and
// - bind()'s arguments are passed as references to ParamStorageTraits::wrap()
//   with no additional copies.
// This test would fail in compile if something is wrong,
// rather than in runtime.
TEST(FunctionalTest, WrapUnwrap) {
  std::unique_ptr<Function<int()>> function =
      bind(processUnwrappedClass, ClassToBeWrapped(3), 7);
  EXPECT_EQ(21, (*function)());
}

TEST(FunctionalTest, WrapUnwrapInPartialBind) {
  std::unique_ptr<Function<int(int)>> partiallyBoundFunction =
      bind(processUnwrappedClass, ClassToBeWrapped(3));
  EXPECT_EQ(21, (*partiallyBoundFunction)(7));
}

bool lotsOfArguments(int first,
                     int second,
                     int third,
                     int fourth,
                     int fifth,
                     int sixth,
                     int seventh,
                     int eighth,
                     int ninth,
                     int tenth) {
  return first == 1 && second == 2 && third == 3 && fourth == 4 && fifth == 5 &&
         sixth == 6 && seventh == 7 && eighth == 8 && ninth == 9 && tenth == 10;
}

TEST(FunctionalTest, LotsOfBoundVariables) {
  std::unique_ptr<Function<bool(int, int)>> eightBound =
      bind(lotsOfArguments, 1, 2, 3, 4, 5, 6, 7, 8);
  EXPECT_TRUE((*eightBound)(9, 10));

  std::unique_ptr<Function<bool(int)>> nineBound =
      bind(lotsOfArguments, 1, 2, 3, 4, 5, 6, 7, 8, 9);
  EXPECT_TRUE((*nineBound)(10));

  std::unique_ptr<Function<bool()>> allBound =
      bind(lotsOfArguments, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
  EXPECT_TRUE((*allBound)());
}

class MoveOnly {
 public:
  explicit MoveOnly(int value) : m_value(value) {}
  MoveOnly(MoveOnly&& other) : m_value(other.m_value) {
    // Reset the value on move.
    other.m_value = 0;
  }

  int value() const { return m_value; }

 private:
  MoveOnly(const MoveOnly&) = delete;
  MoveOnly& operator=(const MoveOnly&) = delete;

  // Disable move-assignment, since it isn't used within bind().
  MoveOnly& operator=(MoveOnly&&) = delete;

  int m_value;
};

int singleMoveOnlyByRvalueReference(MoveOnly&& moveOnly) {
  int value = moveOnly.value();
  MoveOnly(std::move(moveOnly));
  return value;
}

int tripleMoveOnlysByRvalueReferences(MoveOnly&& first,
                                      MoveOnly&& second,
                                      MoveOnly&& third) {
  int value = first.value() + second.value() + third.value();
  MoveOnly(std::move(first));
  MoveOnly(std::move(second));
  MoveOnly(std::move(third));
  return value;
}

int singleMoveOnlyByValue(MoveOnly moveOnly) {
  return moveOnly.value();
}

int tripleMoveOnlysByValues(MoveOnly first, MoveOnly second, MoveOnly third) {
  return first.value() + second.value() + third.value();
}

TEST(FunctionalTest, BindMoveOnlyObjects) {
  MoveOnly one(1);
  std::unique_ptr<Function<int()>> bound =
      bind(singleMoveOnlyByRvalueReference, passed(std::move(one)));
  EXPECT_EQ(0, one.value());  // Should be moved away.
  EXPECT_EQ(1, (*bound)());
  // The stored value must be cleared in the first function call.
  EXPECT_EQ(0, (*bound)());

  bound = bind(singleMoveOnlyByValue, passed(MoveOnly(1)));
  EXPECT_EQ(1, (*bound)());
  EXPECT_EQ(0, (*bound)());

  bound = bind(tripleMoveOnlysByRvalueReferences, passed(MoveOnly(1)),
               passed(MoveOnly(2)), passed(MoveOnly(3)));
  EXPECT_EQ(6, (*bound)());
  EXPECT_EQ(0, (*bound)());

  bound = bind(tripleMoveOnlysByValues, passed(MoveOnly(1)),
               passed(MoveOnly(2)), passed(MoveOnly(3)));
  EXPECT_EQ(6, (*bound)());
  EXPECT_EQ(0, (*bound)());
}

class CountCopy {
 public:
  CountCopy() : m_copies(0) {}
  CountCopy(const CountCopy& other) : m_copies(other.m_copies + 1) {}

  int copies() const { return m_copies; }

 private:
  // Copy/move-assignment is not needed in the test.
  CountCopy& operator=(const CountCopy&) = delete;
  CountCopy& operator=(CountCopy&&) = delete;

  int m_copies;
};

int takeCountCopyAsConstReference(const CountCopy& counter) {
  return counter.copies();
}

int takeCountCopyAsValue(CountCopy counter) {
  return counter.copies();
}

TEST(FunctionalTest, CountCopiesOfBoundArguments) {
  CountCopy lvalue;
  std::unique_ptr<Function<int()>> bound =
      bind(takeCountCopyAsConstReference, lvalue);
  EXPECT_EQ(2, (*bound)());  // wrapping and unwrapping.

  bound = bind(takeCountCopyAsConstReference, CountCopy());  // Rvalue.
  EXPECT_EQ(2, (*bound)());

  bound = bind(takeCountCopyAsValue, lvalue);
  // wrapping, unwrapping and copying in the final function argument.
  EXPECT_EQ(3, (*bound)());

  bound = bind(takeCountCopyAsValue, CountCopy());
  EXPECT_EQ(3, (*bound)());
}

TEST(FunctionalTest, MoveUnboundArgumentsByRvalueReference) {
  std::unique_ptr<Function<int(MoveOnly &&)>> boundSingle =
      bind(singleMoveOnlyByRvalueReference);
  EXPECT_EQ(1, (*boundSingle)(MoveOnly(1)));
  EXPECT_EQ(42, (*boundSingle)(MoveOnly(42)));

  std::unique_ptr<Function<int(MoveOnly&&, MoveOnly&&, MoveOnly &&)>>
      boundTriple = bind(tripleMoveOnlysByRvalueReferences);
  EXPECT_EQ(6, (*boundTriple)(MoveOnly(1), MoveOnly(2), MoveOnly(3)));
  EXPECT_EQ(666, (*boundTriple)(MoveOnly(111), MoveOnly(222), MoveOnly(333)));

  std::unique_ptr<Function<int(MoveOnly)>> boundSingleByValue =
      bind(singleMoveOnlyByValue);
  EXPECT_EQ(1, (*boundSingleByValue)(MoveOnly(1)));

  std::unique_ptr<Function<int(MoveOnly, MoveOnly, MoveOnly)>>
      boundTripleByValue = bind(tripleMoveOnlysByValues);
  EXPECT_EQ(6, (*boundTripleByValue)(MoveOnly(1), MoveOnly(2), MoveOnly(3)));
}

TEST(FunctionalTest, CountCopiesOfUnboundArguments) {
  CountCopy lvalue;
  std::unique_ptr<Function<int(const CountCopy&)>> bound1 =
      bind(takeCountCopyAsConstReference);
  EXPECT_EQ(0, (*bound1)(lvalue));  // No copies!
  EXPECT_EQ(0, (*bound1)(CountCopy()));

  std::unique_ptr<Function<int(CountCopy)>> bound2 = bind(takeCountCopyAsValue);
  // At Function::operator(), at Callback::Run() and at the destination
  // function.
  EXPECT_EQ(3, (*bound2)(lvalue));
  // Compiler is allowed to optimize one copy away if the argument is rvalue.
  EXPECT_LE((*bound2)(CountCopy()), 2);
}

TEST(FunctionalTest, WeakPtr) {
  HasWeakPtrSupport obj;
  int counter = 0;
  std::unique_ptr<WTF::Closure> bound =
      WTF::bind(&HasWeakPtrSupport::increment, obj.createWeakPtr(),
                WTF::unretained(&counter));

  (*bound)();
  EXPECT_FALSE(bound->isCancelled());
  EXPECT_EQ(1, counter);

  obj.revokeAll();
  EXPECT_TRUE(bound->isCancelled());
  (*bound)();
  EXPECT_EQ(1, counter);
}

}  // anonymous namespace

}  // namespace WTF