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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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,
#include <type_traits>
#include <utility>
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/Maybe.h"
using mozilla::Maybe;
using mozilla::Nothing;
using mozilla::Some;
using mozilla::SomeRef;
using mozilla::ToMaybe;
using mozilla::ToMaybeRef;
#define RUN_TEST(t) \
do { \
bool cond = (t()); \
MOZ_RELEASE_ASSERT(cond, "Unexpectedly returned false during test: " #t); \
cond = AllDestructorsWereCalled(); \
MOZ_RELEASE_ASSERT(cond, \
"Failed to destroy all objects during test: " #t); \
} while (false)
enum Status {
eWasDefaultConstructed,
eWasConstructed,
eWasCopyConstructed,
eWasMoveConstructed,
eWasConstMoveConstructed,
eWasAssigned,
eWasCopyAssigned,
eWasMoveAssigned,
eWasCopiedFrom,
eWasMovedFrom,
eWasConstMovedFrom,
};
static size_t sUndestroyedObjects = 0;
static bool AllDestructorsWereCalled() { return sUndestroyedObjects == 0; }
struct BasicValue {
BasicValue() : mStatus(eWasDefaultConstructed), mTag(0) {
++sUndestroyedObjects;
}
explicit BasicValue(int aTag) : mStatus(eWasConstructed), mTag(aTag) {
++sUndestroyedObjects;
}
BasicValue(const BasicValue& aOther)
: mStatus(eWasCopyConstructed), mTag(aOther.mTag) {
++sUndestroyedObjects;
}
BasicValue(BasicValue&& aOther)
: mStatus(eWasMoveConstructed), mTag(aOther.mTag) {
++sUndestroyedObjects;
aOther.mStatus = eWasMovedFrom;
aOther.mTag = 0;
}
BasicValue(const BasicValue&& aOther)
: mStatus(eWasConstMoveConstructed), mTag(aOther.mTag) {
++sUndestroyedObjects;
aOther.mStatus = eWasConstMovedFrom;
}
~BasicValue() { --sUndestroyedObjects; }
BasicValue& operator=(const BasicValue& aOther) {
mStatus = eWasCopyAssigned;
mTag = aOther.mTag;
return *this;
}
BasicValue& operator=(BasicValue&& aOther) {
mStatus = eWasMoveAssigned;
mTag = aOther.mTag;
aOther.mStatus = eWasMovedFrom;
aOther.mTag = 0;
return *this;
}
bool operator==(const BasicValue& aOther) const {
return mTag == aOther.mTag;
}
bool operator<(const BasicValue& aOther) const { return mTag < aOther.mTag; }
Status GetStatus() const { return mStatus; }
void SetTag(int aValue) { mTag = aValue; }
int GetTag() const { return mTag; }
private:
mutable Status mStatus;
int mTag;
};
struct UncopyableValue {
UncopyableValue() : mStatus(eWasDefaultConstructed) { ++sUndestroyedObjects; }
UncopyableValue(UncopyableValue&& aOther) : mStatus(eWasMoveConstructed) {
++sUndestroyedObjects;
aOther.mStatus = eWasMovedFrom;
}
~UncopyableValue() { --sUndestroyedObjects; }
UncopyableValue& operator=(UncopyableValue&& aOther) {
mStatus = eWasMoveAssigned;
aOther.mStatus = eWasMovedFrom;
return *this;
}
Status GetStatus() { return mStatus; }
private:
UncopyableValue(const UncopyableValue& aOther) = delete;
UncopyableValue& operator=(const UncopyableValue& aOther) = delete;
Status mStatus;
};
struct UnmovableValue {
UnmovableValue() : mStatus(eWasDefaultConstructed) { ++sUndestroyedObjects; }
UnmovableValue(const UnmovableValue& aOther) : mStatus(eWasCopyConstructed) {
++sUndestroyedObjects;
}
~UnmovableValue() { --sUndestroyedObjects; }
UnmovableValue& operator=(const UnmovableValue& aOther) {
mStatus = eWasCopyAssigned;
return *this;
}
Status GetStatus() { return mStatus; }
UnmovableValue(UnmovableValue&& aOther) = delete;
UnmovableValue& operator=(UnmovableValue&& aOther) = delete;
private:
Status mStatus;
};
struct UncopyableUnmovableValue {
UncopyableUnmovableValue() : mStatus(eWasDefaultConstructed) {
++sUndestroyedObjects;
}
explicit UncopyableUnmovableValue(int) : mStatus(eWasConstructed) {
++sUndestroyedObjects;
}
~UncopyableUnmovableValue() { --sUndestroyedObjects; }
Status GetStatus() const { return mStatus; }
private:
UncopyableUnmovableValue(const UncopyableUnmovableValue& aOther) = delete;
UncopyableUnmovableValue& operator=(const UncopyableUnmovableValue& aOther) =
delete;
UncopyableUnmovableValue(UncopyableUnmovableValue&& aOther) = delete;
UncopyableUnmovableValue& operator=(UncopyableUnmovableValue&& aOther) =
delete;
Status mStatus;
};
static_assert(std::is_trivially_destructible_v<Maybe<int>>);
static_assert(std::is_trivially_copy_constructible_v<Maybe<int>>);
static_assert(std::is_trivially_copy_assignable_v<Maybe<int>>);
static_assert(42 == Some(42).value());
static_assert(42 == Some(42).valueOr(43));
static_assert(42 == Maybe<int>{}.valueOr(42));
static_assert(42 == Some(42).valueOrFrom([] { return 43; }));
static_assert(42 == Maybe<int>{}.valueOrFrom([] { return 42; }));
static_assert(Some(43) == [] {
auto val = Some(42);
val.apply([](int& val) { val += 1; });
return val;
}());
static_assert(Some(43) == Some(42).map([](int val) { return val + 1; }));
static_assert(Maybe<int>(std::in_place, 43) ==
Maybe<int>(std::in_place, 42).map([](int val) {
return val + 1;
}));
struct TriviallyDestructible {
TriviallyDestructible() { // not trivially constructible
}
};
static_assert(std::is_trivially_destructible_v<Maybe<TriviallyDestructible>>);
struct UncopyableValueLiteralType {
explicit constexpr UncopyableValueLiteralType(int aValue) : mValue{aValue} {}
UncopyableValueLiteralType(UncopyableValueLiteralType&&) = default;
UncopyableValueLiteralType& operator=(UncopyableValueLiteralType&&) = default;
int mValue;
};
static_assert(
std::is_trivially_destructible_v<Maybe<UncopyableValueLiteralType>>);
static_assert(!std::is_copy_constructible_v<Maybe<UncopyableValueLiteralType>>);
static_assert(!std::is_copy_assignable_v<Maybe<UncopyableValueLiteralType>>);
static_assert(std::is_move_constructible_v<Maybe<UncopyableValueLiteralType>>);
static_assert(std::is_move_assignable_v<Maybe<UncopyableValueLiteralType>>);
constexpr Maybe<UncopyableValueLiteralType> someUncopyable =
Some(UncopyableValueLiteralType{42});
static_assert(someUncopyable.isSome());
static_assert(42 == someUncopyable->mValue);
constexpr Maybe<UncopyableValueLiteralType> someUncopyableAssigned = [] {
auto res = Maybe<UncopyableValueLiteralType>{};
res = Some(UncopyableValueLiteralType{42});
return res;
}();
static_assert(someUncopyableAssigned.isSome());
static_assert(42 == someUncopyableAssigned->mValue);
static bool TestBasicFeatures() {
// Check that a Maybe<T> is initialized to Nothing.
Maybe<BasicValue> mayValue;
static_assert(std::is_same_v<BasicValue, decltype(mayValue)::ValueType>,
"Should have BasicValue ValueType");
MOZ_RELEASE_ASSERT(!mayValue);
MOZ_RELEASE_ASSERT(!mayValue.isSome());
MOZ_RELEASE_ASSERT(mayValue.isNothing());
// Check that emplace() default constructs and the accessors work.
mayValue.emplace();
MOZ_RELEASE_ASSERT(mayValue);
MOZ_RELEASE_ASSERT(mayValue.isSome());
MOZ_RELEASE_ASSERT(!mayValue.isNothing());
MOZ_RELEASE_ASSERT(*mayValue == BasicValue());
static_assert(std::is_same_v<BasicValue&, decltype(*mayValue)>,
"operator*() should return a BasicValue&");
MOZ_RELEASE_ASSERT(mayValue.value() == BasicValue());
static_assert(std::is_same_v<BasicValue, decltype(mayValue.value())>,
"value() should return a BasicValue");
MOZ_RELEASE_ASSERT(mayValue.ref() == BasicValue());
static_assert(std::is_same_v<BasicValue&, decltype(mayValue.ref())>,
"ref() should return a BasicValue&");
MOZ_RELEASE_ASSERT(mayValue.ptr() != nullptr);
static_assert(std::is_same_v<BasicValue*, decltype(mayValue.ptr())>,
"ptr() should return a BasicValue*");
MOZ_RELEASE_ASSERT(mayValue->GetStatus() == eWasDefaultConstructed);
// Check that reset() works.
mayValue.reset();
MOZ_RELEASE_ASSERT(!mayValue);
MOZ_RELEASE_ASSERT(!mayValue.isSome());
MOZ_RELEASE_ASSERT(mayValue.isNothing());
// Check that emplace(T1) calls the correct constructor.
mayValue.emplace(1);
MOZ_RELEASE_ASSERT(mayValue);
MOZ_RELEASE_ASSERT(mayValue->GetStatus() == eWasConstructed);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
mayValue.reset();
MOZ_RELEASE_ASSERT(!mayValue);
{
// Check that Maybe(std::in_place, T1) calls the correct constructor.
const auto mayValueConstructed = Maybe<BasicValue>(std::in_place, 1);
MOZ_RELEASE_ASSERT(mayValueConstructed);
MOZ_RELEASE_ASSERT(mayValueConstructed->GetStatus() == eWasConstructed);
MOZ_RELEASE_ASSERT(mayValueConstructed->GetTag() == 1);
}
// Check that Some() and Nothing() work.
mayValue = Some(BasicValue(2));
MOZ_RELEASE_ASSERT(mayValue);
MOZ_RELEASE_ASSERT(mayValue->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 2);
mayValue = Nothing();
MOZ_RELEASE_ASSERT(!mayValue);
// Check that the accessors work through a const ref.
mayValue.emplace();
const Maybe<BasicValue>& mayValueCRef = mayValue;
MOZ_RELEASE_ASSERT(mayValueCRef);
MOZ_RELEASE_ASSERT(mayValueCRef.isSome());
MOZ_RELEASE_ASSERT(!mayValueCRef.isNothing());
MOZ_RELEASE_ASSERT(*mayValueCRef == BasicValue());
static_assert(std::is_same_v<const BasicValue&, decltype(*mayValueCRef)>,
"operator*() should return a BasicValue");
MOZ_RELEASE_ASSERT(mayValueCRef.value() == BasicValue());
static_assert(std::is_same_v<BasicValue, decltype(mayValueCRef.value())>,
"value() should return a BasicValue");
MOZ_RELEASE_ASSERT(mayValueCRef.ref() == BasicValue());
static_assert(std::is_same_v<const BasicValue&, decltype(mayValueCRef.ref())>,
"ref() should return a const BasicValue&");
MOZ_RELEASE_ASSERT(mayValueCRef.ptr() != nullptr);
static_assert(std::is_same_v<const BasicValue*, decltype(mayValueCRef.ptr())>,
"ptr() should return a const BasicValue*");
MOZ_RELEASE_ASSERT(mayValueCRef->GetStatus() == eWasDefaultConstructed);
mayValue.reset();
// Check that we can create and reference Maybe<const Type>.
Maybe<const BasicValue> mayCValue1 = Some(BasicValue(5));
MOZ_RELEASE_ASSERT(mayCValue1);
MOZ_RELEASE_ASSERT(mayCValue1.isSome());
MOZ_RELEASE_ASSERT(*mayCValue1 == BasicValue(5));
const Maybe<const BasicValue>& mayCValue1Ref = mayCValue1;
MOZ_RELEASE_ASSERT(mayCValue1Ref == mayCValue1);
MOZ_RELEASE_ASSERT(*mayCValue1Ref == BasicValue(5));
Maybe<const BasicValue> mayCValue2;
mayCValue2.emplace(6);
MOZ_RELEASE_ASSERT(mayCValue2);
MOZ_RELEASE_ASSERT(mayCValue2.isSome());
MOZ_RELEASE_ASSERT(*mayCValue2 == BasicValue(6));
// Check that accessors work through rvalue-references.
MOZ_RELEASE_ASSERT(Some(BasicValue()));
MOZ_RELEASE_ASSERT(Some(BasicValue()).isSome());
MOZ_RELEASE_ASSERT(!Some(BasicValue()).isNothing());
MOZ_RELEASE_ASSERT(*Some(BasicValue()) == BasicValue());
static_assert(std::is_same_v<BasicValue&&, decltype(*Some(BasicValue()))>,
"operator*() should return a BasicValue&&");
MOZ_RELEASE_ASSERT(Some(BasicValue()).value() == BasicValue());
static_assert(
std::is_same_v<BasicValue, decltype(Some(BasicValue()).value())>,
"value() should return a BasicValue");
MOZ_RELEASE_ASSERT(Some(BasicValue()).ref() == BasicValue());
static_assert(
std::is_same_v<BasicValue&&, decltype(Some(BasicValue()).ref())>,
"ref() should return a BasicValue&&");
MOZ_RELEASE_ASSERT(Some(BasicValue()).ptr() != nullptr);
static_assert(std::is_same_v<BasicValue*, decltype(Some(BasicValue()).ptr())>,
"ptr() should return a BasicValue*");
MOZ_RELEASE_ASSERT(Some(BasicValue())->GetStatus() == eWasMoveConstructed);
// Check that accessors work through const-rvalue-references.
auto MakeConstMaybe = []() -> const Maybe<BasicValue> {
return Some(BasicValue());
};
MOZ_RELEASE_ASSERT(MakeConstMaybe());
MOZ_RELEASE_ASSERT(MakeConstMaybe().isSome());
MOZ_RELEASE_ASSERT(!MakeConstMaybe().isNothing());
MOZ_RELEASE_ASSERT(*MakeConstMaybe() == BasicValue());
static_assert(std::is_same_v<const BasicValue&&, decltype(*MakeConstMaybe())>,
"operator*() should return a const BasicValue&&");
MOZ_RELEASE_ASSERT(MakeConstMaybe().value() == BasicValue());
static_assert(std::is_same_v<BasicValue, decltype(MakeConstMaybe().value())>,
"value() should return a BasicValue");
MOZ_RELEASE_ASSERT(MakeConstMaybe().ref() == BasicValue());
static_assert(
std::is_same_v<const BasicValue&&, decltype(MakeConstMaybe().ref())>,
"ref() should return a const BasicValue&&");
MOZ_RELEASE_ASSERT(MakeConstMaybe().ptr() != nullptr);
static_assert(
std::is_same_v<const BasicValue*, decltype(MakeConstMaybe().ptr())>,
"ptr() should return a const BasicValue*");
MOZ_RELEASE_ASSERT(MakeConstMaybe()->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(BasicValue(*MakeConstMaybe()).GetStatus() ==
eWasConstMoveConstructed);
// Check that take works
mayValue = Some(BasicValue(6));
Maybe taken = mayValue.take();
MOZ_RELEASE_ASSERT(taken->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(taken == Some(BasicValue(6)));
MOZ_RELEASE_ASSERT(!mayValue.isSome());
MOZ_RELEASE_ASSERT(mayValue.take() == Nothing());
// Check that extract works
mayValue = Some(BasicValue(7));
BasicValue extracted = mayValue.extract();
MOZ_RELEASE_ASSERT(extracted.GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(extracted == BasicValue(7));
MOZ_RELEASE_ASSERT(!mayValue.isSome());
return true;
}
template <typename T>
static void TestCopyMaybe() {
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
Maybe<T> dstCopyConstructed = src;
MOZ_RELEASE_ASSERT(2 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstCopyConstructed->GetStatus() == eWasCopyConstructed);
}
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
Maybe<T> dstCopyAssigned;
dstCopyAssigned = src;
MOZ_RELEASE_ASSERT(2 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstCopyAssigned->GetStatus() == eWasCopyConstructed);
}
}
template <typename T>
static void TestMoveMaybe() {
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
Maybe<T> dstMoveConstructed = std::move(src);
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstMoveConstructed->GetStatus() == eWasMoveConstructed);
}
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
Maybe<T> dstMoveAssigned;
dstMoveAssigned = std::move(src);
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstMoveAssigned->GetStatus() == eWasMoveConstructed);
}
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
Maybe<T> dstMoveConstructed = src.take();
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstMoveConstructed->GetStatus() == eWasMoveConstructed);
}
{
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
Maybe<T> src = Some(T());
T dstMoveConstructed = src.extract();
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(dstMoveConstructed.GetStatus() == eWasMoveConstructed);
}
}
static bool TestCopyAndMove() {
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
{
// Check that we get moves when possible for types that can support both
// moves and copies.
{
Maybe<BasicValue> mayBasicValue = Some(BasicValue(1));
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(mayBasicValue->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue->GetTag() == 1);
mayBasicValue = Some(BasicValue(2));
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(mayBasicValue->GetStatus() == eWasMoveAssigned);
MOZ_RELEASE_ASSERT(mayBasicValue->GetTag() == 2);
mayBasicValue.reset();
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
mayBasicValue.emplace(BasicValue(3));
MOZ_RELEASE_ASSERT(1 == sUndestroyedObjects);
MOZ_RELEASE_ASSERT(mayBasicValue->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue->GetTag() == 3);
// Check that we get copies when moves aren't possible.
Maybe<BasicValue> mayBasicValue2 = Some(*mayBasicValue);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetStatus() == eWasCopyConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetTag() == 3);
mayBasicValue->SetTag(4);
mayBasicValue2 = mayBasicValue;
// MOZ_RELEASE_ASSERT(mayBasicValue2->GetStatus() == eWasCopyAssigned);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetTag() == 4);
mayBasicValue->SetTag(5);
mayBasicValue2.reset();
mayBasicValue2.emplace(*mayBasicValue);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetStatus() == eWasCopyConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetTag() == 5);
// Check that std::move() works. (Another sanity check for move support.)
Maybe<BasicValue> mayBasicValue3 = Some(std::move(*mayBasicValue));
MOZ_RELEASE_ASSERT(mayBasicValue3->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue3->GetTag() == 5);
MOZ_RELEASE_ASSERT(mayBasicValue->GetStatus() == eWasMovedFrom);
mayBasicValue2->SetTag(6);
mayBasicValue3 = Some(std::move(*mayBasicValue2));
MOZ_RELEASE_ASSERT(mayBasicValue3->GetStatus() == eWasMoveAssigned);
MOZ_RELEASE_ASSERT(mayBasicValue3->GetTag() == 6);
MOZ_RELEASE_ASSERT(mayBasicValue2->GetStatus() == eWasMovedFrom);
Maybe<BasicValue> mayBasicValue4;
mayBasicValue4.emplace(std::move(*mayBasicValue3));
MOZ_RELEASE_ASSERT(mayBasicValue4->GetStatus() == eWasMoveConstructed);
MOZ_RELEASE_ASSERT(mayBasicValue4->GetTag() == 6);
MOZ_RELEASE_ASSERT(mayBasicValue3->GetStatus() == eWasMovedFrom);
}
TestCopyMaybe<BasicValue>();
TestMoveMaybe<BasicValue>();
}
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
{
// Check that we always get copies for types that don't support moves.
{
Maybe<UnmovableValue> mayUnmovableValue = Some(UnmovableValue());
MOZ_RELEASE_ASSERT(mayUnmovableValue->GetStatus() == eWasCopyConstructed);
mayUnmovableValue.reset();
mayUnmovableValue.emplace(UnmovableValue());
MOZ_RELEASE_ASSERT(mayUnmovableValue->GetStatus() == eWasCopyConstructed);
}
TestCopyMaybe<UnmovableValue>();
static_assert(std::is_copy_constructible_v<Maybe<UnmovableValue>>);
static_assert(std::is_copy_assignable_v<Maybe<UnmovableValue>>);
static_assert(!std::is_move_constructible_v<Maybe<UnmovableValue>>);
static_assert(!std::is_move_assignable_v<Maybe<UnmovableValue>>);
}
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
{
// Check that types that only support moves, but not copies, work.
{
Maybe<UncopyableValue> mayUncopyableValue = Some(UncopyableValue());
MOZ_RELEASE_ASSERT(mayUncopyableValue->GetStatus() ==
eWasMoveConstructed);
mayUncopyableValue = Some(UncopyableValue());
MOZ_RELEASE_ASSERT(mayUncopyableValue->GetStatus() == eWasMoveAssigned);
mayUncopyableValue.reset();
mayUncopyableValue.emplace(UncopyableValue());
MOZ_RELEASE_ASSERT(mayUncopyableValue->GetStatus() ==
eWasMoveConstructed);
mayUncopyableValue = Nothing();
}
TestMoveMaybe<BasicValue>();
static_assert(!std::is_copy_constructible_v<Maybe<UncopyableValue>>);
static_assert(!std::is_copy_assignable_v<Maybe<UncopyableValue>>);
static_assert(std::is_move_constructible_v<Maybe<UncopyableValue>>);
static_assert(std::is_move_assignable_v<Maybe<UncopyableValue>>);
}
MOZ_RELEASE_ASSERT(0 == sUndestroyedObjects);
{ // Check that types that support neither moves or copies work.
{
const auto mayUncopyableUnmovableValueConstructed =
Maybe<UncopyableUnmovableValue>{std::in_place};
MOZ_RELEASE_ASSERT(mayUncopyableUnmovableValueConstructed->GetStatus() ==
eWasDefaultConstructed);
}
Maybe<UncopyableUnmovableValue> mayUncopyableUnmovableValue;
mayUncopyableUnmovableValue.emplace();
MOZ_RELEASE_ASSERT(mayUncopyableUnmovableValue->GetStatus() ==
eWasDefaultConstructed);
mayUncopyableUnmovableValue.reset();
mayUncopyableUnmovableValue.emplace(0);
MOZ_RELEASE_ASSERT(mayUncopyableUnmovableValue->GetStatus() ==
eWasConstructed);
mayUncopyableUnmovableValue = Nothing();
static_assert(
!std::is_copy_constructible_v<Maybe<UncopyableUnmovableValue>>);
static_assert(!std::is_copy_assignable_v<Maybe<UncopyableUnmovableValue>>);
static_assert(
!std::is_move_constructible_v<Maybe<UncopyableUnmovableValue>>);
static_assert(!std::is_move_assignable_v<Maybe<UncopyableUnmovableValue>>);
}
{
// Test copy and move with a trivially copyable and trivially destructible
// type.
{
constexpr Maybe<int> src = Some(42);
constexpr Maybe<int> dstCopyConstructed = src;
static_assert(src.isSome());
static_assert(dstCopyConstructed.isSome());
static_assert(42 == *src);
static_assert(42 == *dstCopyConstructed);
static_assert(42 == dstCopyConstructed.value());
}
{
const Maybe<int> src = Some(42);
Maybe<int> dstCopyAssigned;
dstCopyAssigned = src;
MOZ_RELEASE_ASSERT(src.isSome());
MOZ_RELEASE_ASSERT(dstCopyAssigned.isSome());
MOZ_RELEASE_ASSERT(42 == *src);
MOZ_RELEASE_ASSERT(42 == *dstCopyAssigned);
}
{
Maybe<int> src = Some(42);
const Maybe<int> dstMoveConstructed = std::move(src);
MOZ_RELEASE_ASSERT(!src.isSome());
MOZ_RELEASE_ASSERT(dstMoveConstructed.isSome());
MOZ_RELEASE_ASSERT(42 == *dstMoveConstructed);
}
{
Maybe<int> src = Some(42);
Maybe<int> dstMoveAssigned;
dstMoveAssigned = std::move(src);
MOZ_RELEASE_ASSERT(!src.isSome());
MOZ_RELEASE_ASSERT(dstMoveAssigned.isSome());
MOZ_RELEASE_ASSERT(42 == *dstMoveAssigned);
}
}
return true;
}
static BasicValue* sStaticBasicValue = nullptr;
static BasicValue MakeBasicValue() { return BasicValue(9); }
static BasicValue& MakeBasicValueRef() { return *sStaticBasicValue; }
static BasicValue* MakeBasicValuePtr() { return sStaticBasicValue; }
static bool TestFunctionalAccessors() {
BasicValue value(9);
sStaticBasicValue = new BasicValue(9);
// Check that the 'some' case of functional accessors works.
Maybe<BasicValue> someValue = Some(BasicValue(3));
MOZ_RELEASE_ASSERT(someValue.valueOr(value) == BasicValue(3));
static_assert(std::is_same_v<BasicValue, decltype(someValue.valueOr(value))>,
"valueOr should return a BasicValue");
MOZ_RELEASE_ASSERT(someValue.valueOrFrom(&MakeBasicValue) == BasicValue(3));
static_assert(
std::is_same_v<BasicValue,
decltype(someValue.valueOrFrom(&MakeBasicValue))>,
"valueOrFrom should return a BasicValue");
MOZ_RELEASE_ASSERT(someValue.ptrOr(&value) != &value);
static_assert(std::is_same_v<BasicValue*, decltype(someValue.ptrOr(&value))>,
"ptrOr should return a BasicValue*");
MOZ_RELEASE_ASSERT(*someValue.ptrOrFrom(&MakeBasicValuePtr) == BasicValue(3));
static_assert(
std::is_same_v<BasicValue*,
decltype(someValue.ptrOrFrom(&MakeBasicValuePtr))>,
"ptrOrFrom should return a BasicValue*");
MOZ_RELEASE_ASSERT(someValue.refOr(value) == BasicValue(3));
static_assert(std::is_same_v<BasicValue&, decltype(someValue.refOr(value))>,
"refOr should return a BasicValue&");
MOZ_RELEASE_ASSERT(someValue.refOrFrom(&MakeBasicValueRef) == BasicValue(3));
static_assert(
std::is_same_v<BasicValue&,
decltype(someValue.refOrFrom(&MakeBasicValueRef))>,
"refOrFrom should return a BasicValue&");
// Check that the 'some' case works through a const reference.
const Maybe<BasicValue>& someValueCRef = someValue;
MOZ_RELEASE_ASSERT(someValueCRef.valueOr(value) == BasicValue(3));
static_assert(
std::is_same_v<BasicValue, decltype(someValueCRef.valueOr(value))>,
"valueOr should return a BasicValue");
MOZ_RELEASE_ASSERT(someValueCRef.valueOrFrom(&MakeBasicValue) ==
BasicValue(3));
static_assert(
std::is_same_v<BasicValue,
decltype(someValueCRef.valueOrFrom(&MakeBasicValue))>,
"valueOrFrom should return a BasicValue");
MOZ_RELEASE_ASSERT(someValueCRef.ptrOr(&value) != &value);
static_assert(
std::is_same_v<const BasicValue*, decltype(someValueCRef.ptrOr(&value))>,
"ptrOr should return a const BasicValue*");
MOZ_RELEASE_ASSERT(*someValueCRef.ptrOrFrom(&MakeBasicValuePtr) ==
BasicValue(3));
static_assert(
std::is_same_v<const BasicValue*,
decltype(someValueCRef.ptrOrFrom(&MakeBasicValuePtr))>,
"ptrOrFrom should return a const BasicValue*");
MOZ_RELEASE_ASSERT(someValueCRef.refOr(value) == BasicValue(3));
static_assert(
std::is_same_v<const BasicValue&, decltype(someValueCRef.refOr(value))>,
"refOr should return a const BasicValue&");
MOZ_RELEASE_ASSERT(someValueCRef.refOrFrom(&MakeBasicValueRef) ==
BasicValue(3));
static_assert(
std::is_same_v<const BasicValue&,
decltype(someValueCRef.refOrFrom(&MakeBasicValueRef))>,
"refOrFrom should return a const BasicValue&");
// Check that the 'none' case of functional accessors works.
Maybe<BasicValue> noneValue;
MOZ_RELEASE_ASSERT(noneValue.valueOr(value) == BasicValue(9));
static_assert(std::is_same_v<BasicValue, decltype(noneValue.valueOr(value))>,
"valueOr should return a BasicValue");
MOZ_RELEASE_ASSERT(noneValue.valueOrFrom(&MakeBasicValue) == BasicValue(9));
static_assert(
std::is_same_v<BasicValue,
decltype(noneValue.valueOrFrom(&MakeBasicValue))>,
"valueOrFrom should return a BasicValue");
MOZ_RELEASE_ASSERT(noneValue.ptrOr(&value) == &value);
static_assert(std::is_same_v<BasicValue*, decltype(noneValue.ptrOr(&value))>,
"ptrOr should return a BasicValue*");
MOZ_RELEASE_ASSERT(*noneValue.ptrOrFrom(&MakeBasicValuePtr) == BasicValue(9));
static_assert(
std::is_same_v<BasicValue*,
decltype(noneValue.ptrOrFrom(&MakeBasicValuePtr))>,
"ptrOrFrom should return a BasicValue*");
MOZ_RELEASE_ASSERT(noneValue.refOr(value) == BasicValue(9));
static_assert(std::is_same_v<BasicValue&, decltype(noneValue.refOr(value))>,
"refOr should return a BasicValue&");
MOZ_RELEASE_ASSERT(noneValue.refOrFrom(&MakeBasicValueRef) == BasicValue(9));
static_assert(
std::is_same_v<BasicValue&,
decltype(noneValue.refOrFrom(&MakeBasicValueRef))>,
"refOrFrom should return a BasicValue&");
// Check that the 'none' case works through a const reference.
const Maybe<BasicValue>& noneValueCRef = noneValue;
MOZ_RELEASE_ASSERT(noneValueCRef.valueOr(value) == BasicValue(9));
static_assert(
std::is_same_v<BasicValue, decltype(noneValueCRef.valueOr(value))>,
"valueOr should return a BasicValue");
MOZ_RELEASE_ASSERT(noneValueCRef.valueOrFrom(&MakeBasicValue) ==
BasicValue(9));
static_assert(
std::is_same_v<BasicValue,
decltype(noneValueCRef.valueOrFrom(&MakeBasicValue))>,
"valueOrFrom should return a BasicValue");
MOZ_RELEASE_ASSERT(noneValueCRef.ptrOr(&value) == &value);
static_assert(
std::is_same_v<const BasicValue*, decltype(noneValueCRef.ptrOr(&value))>,
"ptrOr should return a const BasicValue*");
MOZ_RELEASE_ASSERT(*noneValueCRef.ptrOrFrom(&MakeBasicValuePtr) ==
BasicValue(9));
static_assert(
std::is_same_v<const BasicValue*,
decltype(noneValueCRef.ptrOrFrom(&MakeBasicValuePtr))>,
"ptrOrFrom should return a const BasicValue*");
MOZ_RELEASE_ASSERT(noneValueCRef.refOr(value) == BasicValue(9));
static_assert(
std::is_same_v<const BasicValue&, decltype(noneValueCRef.refOr(value))>,
"refOr should return a const BasicValue&");
MOZ_RELEASE_ASSERT(noneValueCRef.refOrFrom(&MakeBasicValueRef) ==
BasicValue(9));
static_assert(
std::is_same_v<const BasicValue&,
decltype(noneValueCRef.refOrFrom(&MakeBasicValueRef))>,
"refOrFrom should return a const BasicValue&");
// Clean up so the undestroyed objects count stays accurate.
delete sStaticBasicValue;
sStaticBasicValue = nullptr;
return true;
}
static bool gFunctionWasApplied = false;
static void IncrementTag(BasicValue& aValue) {
gFunctionWasApplied = true;
aValue.SetTag(aValue.GetTag() + 1);
}
static void AccessValue(const BasicValue&) { gFunctionWasApplied = true; }
struct IncrementTagFunctor {
IncrementTagFunctor() : mBy(1) {}
void operator()(BasicValue& aValue) {
aValue.SetTag(aValue.GetTag() + mBy.GetTag());
}
BasicValue mBy;
};
static bool TestApply() {
// Check that apply handles the 'Nothing' case.
gFunctionWasApplied = false;
Maybe<BasicValue> mayValue;
mayValue.apply(&IncrementTag);
mayValue.apply(&AccessValue);
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
// Check that apply handles the 'Some' case.
mayValue = Some(BasicValue(1));
mayValue.apply(&IncrementTag);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 2);
gFunctionWasApplied = false;
mayValue.apply(&AccessValue);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
// Check that apply works with a const reference.
const Maybe<BasicValue>& mayValueCRef = mayValue;
gFunctionWasApplied = false;
mayValueCRef.apply(&AccessValue);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
// Check that apply works with functors.
IncrementTagFunctor tagIncrementer;
MOZ_RELEASE_ASSERT(tagIncrementer.mBy.GetStatus() == eWasConstructed);
mayValue = Some(BasicValue(1));
mayValue.apply(tagIncrementer);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 2);
MOZ_RELEASE_ASSERT(tagIncrementer.mBy.GetStatus() == eWasConstructed);
// Check that apply works with lambda expressions.
int32_t two = 2;
gFunctionWasApplied = false;
mayValue = Some(BasicValue(2));
mayValue.apply([&](BasicValue& aVal) { aVal.SetTag(aVal.GetTag() * two); });
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 4);
mayValue.apply([=](BasicValue& aVal) { aVal.SetTag(aVal.GetTag() * two); });
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 8);
mayValueCRef.apply(
[&](const BasicValue& aVal) { gFunctionWasApplied = true; });
MOZ_RELEASE_ASSERT(gFunctionWasApplied == true);
// Check that apply can move the contained value.
mayValue = Some(BasicValue(1));
Maybe<BasicValue> otherValue;
std::move(mayValue).apply(
[&](BasicValue&& aVal) { otherValue = Some(std::move(aVal)); });
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
MOZ_RELEASE_ASSERT(otherValue->GetStatus() == eWasMoveConstructed);
return true;
}
static int TimesTwo(const BasicValue& aValue) { return aValue.GetTag() * 2; }
static int TimesTwoAndResetOriginal(BasicValue& aValue) {
int tag = aValue.GetTag();
aValue.SetTag(1);
return tag * 2;
}
struct MultiplyTagFunctor {
MultiplyTagFunctor() : mBy(2) {}
int operator()(BasicValue& aValue) { return aValue.GetTag() * mBy.GetTag(); }
BasicValue mBy;
};
static bool TestMap() {
// Check that map handles the 'Nothing' case.
Maybe<BasicValue> mayValue;
MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwo) == Nothing());
static_assert(std::is_same_v<Maybe<int>, decltype(mayValue.map(&TimesTwo))>,
"map(TimesTwo) should return a Maybe<int>");
MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwoAndResetOriginal) == Nothing());
// Check that map handles the 'Some' case.
mayValue = Some(BasicValue(2));
MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwo) == Some(4));
MOZ_RELEASE_ASSERT(mayValue.map(&TimesTwoAndResetOriginal) == Some(4));
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
mayValue = Some(BasicValue(2));
// Check that map works with a const reference.
mayValue->SetTag(2);
const Maybe<BasicValue>& mayValueCRef = mayValue;
MOZ_RELEASE_ASSERT(mayValueCRef.map(&TimesTwo) == Some(4));
static_assert(
std::is_same_v<Maybe<int>, decltype(mayValueCRef.map(&TimesTwo))>,
"map(TimesTwo) should return a Maybe<int>");
// Check that map works with functors.
MultiplyTagFunctor tagMultiplier;
MOZ_RELEASE_ASSERT(tagMultiplier.mBy.GetStatus() == eWasConstructed);
MOZ_RELEASE_ASSERT(mayValue.map(tagMultiplier) == Some(4));
MOZ_RELEASE_ASSERT(tagMultiplier.mBy.GetStatus() == eWasConstructed);
// Check that map works with lambda expressions.
int two = 2;
mayValue = Some(BasicValue(2));
Maybe<int> mappedValue =
mayValue.map([&](const BasicValue& aVal) { return aVal.GetTag() * two; });
MOZ_RELEASE_ASSERT(mappedValue == Some(4));
mappedValue =
mayValue.map([=](const BasicValue& aVal) { return aVal.GetTag() * two; });
MOZ_RELEASE_ASSERT(mappedValue == Some(4));
mappedValue = mayValueCRef.map(
[&](const BasicValue& aVal) { return aVal.GetTag() * two; });
MOZ_RELEASE_ASSERT(mappedValue == Some(4));
// Check that map can move the contained value.
mayValue = Some(BasicValue(1));
Maybe<BasicValue> otherValue = std::move(mayValue).map(
[](BasicValue&& aValue) { return std::move(aValue); });
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
MOZ_RELEASE_ASSERT(otherValue->GetStatus() == eWasMoveConstructed);
// Check that function object qualifiers are preserved when invoked.
struct F {
std::integral_constant<int, 1> operator()(int) & { return {}; }
std::integral_constant<int, 2> operator()(int) const& { return {}; }
std::integral_constant<int, 3> operator()(int) && { return {}; }
std::integral_constant<int, 4> operator()(int) const&& { return {}; }
};
Maybe<int> mi = Some(0);
const Maybe<int> cmi = Some(0);
F f;
static_assert(std::is_same<decltype(mi.map(f)),
Maybe<std::integral_constant<int, 1>>>::value,
"Maybe.map(&)");
MOZ_RELEASE_ASSERT(mi.map(f).value()() == 1);
static_assert(std::is_same<decltype(cmi.map(f)),
Maybe<std::integral_constant<int, 1>>>::value,
"const Maybe.map(&)");
MOZ_RELEASE_ASSERT(cmi.map(f).value()() == 1);
const F cf;
static_assert(std::is_same<decltype(mi.map(cf)),
Maybe<std::integral_constant<int, 2>>>::value,
"Maybe.map(const &)");
MOZ_RELEASE_ASSERT(mi.map(cf).value() == 2);
static_assert(std::is_same<decltype(cmi.map(cf)),
Maybe<std::integral_constant<int, 2>>>::value,
"const Maybe.map(const &)");
MOZ_RELEASE_ASSERT(cmi.map(cf).value() == 2);
static_assert(std::is_same<decltype(mi.map(F{})),
Maybe<std::integral_constant<int, 3>>>::value,
"Maybe.map(&&)");
MOZ_RELEASE_ASSERT(mi.map(F{}).value() == 3);
static_assert(std::is_same<decltype(cmi.map(F{})),
Maybe<std::integral_constant<int, 3>>>::value,
"const Maybe.map(&&)");
MOZ_RELEASE_ASSERT(cmi.map(F{}).value() == 3);
using CF = const F;
static_assert(std::is_same<decltype(mi.map(CF{})),
Maybe<std::integral_constant<int, 4>>>::value,
"Maybe.map(const &&)");
MOZ_RELEASE_ASSERT(mi.map(CF{}).value() == 4);
static_assert(std::is_same<decltype(cmi.map(CF{})),
Maybe<std::integral_constant<int, 4>>>::value,
"const Maybe.map(const &&)");
MOZ_RELEASE_ASSERT(cmi.map(CF{}).value() == 4);
return true;
}
static bool TestToMaybe() {
BasicValue value(1);
BasicValue* nullPointer = nullptr;
// Check that a non-null pointer translates into a Some value.
Maybe<BasicValue> mayValue = ToMaybe(&value);
static_assert(std::is_same_v<Maybe<BasicValue>, decltype(ToMaybe(&value))>,
"ToMaybe should return a Maybe<BasicValue>");
MOZ_RELEASE_ASSERT(mayValue.isSome());
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
MOZ_RELEASE_ASSERT(mayValue->GetStatus() == eWasCopyConstructed);
MOZ_RELEASE_ASSERT(value.GetStatus() != eWasMovedFrom);
// Check that a null pointer translates into a Nothing value.
mayValue = ToMaybe(nullPointer);
static_assert(
std::is_same_v<Maybe<BasicValue>, decltype(ToMaybe(nullPointer))>,
"ToMaybe should return a Maybe<BasicValue>");
MOZ_RELEASE_ASSERT(mayValue.isNothing());
return true;
}
static bool TestComparisonOperators() {
Maybe<BasicValue> nothingValue = Nothing();
Maybe<BasicValue> anotherNothingValue = Nothing();
Maybe<BasicValue> oneValue = Some(BasicValue(1));
Maybe<BasicValue> anotherOneValue = Some(BasicValue(1));
Maybe<BasicValue> twoValue = Some(BasicValue(2));
// Check equality.
MOZ_RELEASE_ASSERT(nothingValue == anotherNothingValue);
MOZ_RELEASE_ASSERT(oneValue == anotherOneValue);
// Check inequality.
MOZ_RELEASE_ASSERT(nothingValue != oneValue);
MOZ_RELEASE_ASSERT(oneValue != nothingValue);
MOZ_RELEASE_ASSERT(oneValue != twoValue);
// Check '<'.
MOZ_RELEASE_ASSERT(nothingValue < oneValue);
MOZ_RELEASE_ASSERT(oneValue < twoValue);
// Check '<='.
MOZ_RELEASE_ASSERT(nothingValue <= anotherNothingValue);
MOZ_RELEASE_ASSERT(nothingValue <= oneValue);
MOZ_RELEASE_ASSERT(oneValue <= oneValue);
MOZ_RELEASE_ASSERT(oneValue <= twoValue);
// Check '>'.
MOZ_RELEASE_ASSERT(oneValue > nothingValue);
MOZ_RELEASE_ASSERT(twoValue > oneValue);
// Check '>='.
MOZ_RELEASE_ASSERT(nothingValue >= anotherNothingValue);
MOZ_RELEASE_ASSERT(oneValue >= nothingValue);
MOZ_RELEASE_ASSERT(oneValue >= oneValue);
MOZ_RELEASE_ASSERT(twoValue >= oneValue);
return true;
}
// Check that Maybe<> can wrap a superclass that happens to also be a concrete
// class (i.e. that the compiler doesn't warn when we invoke the superclass's
// destructor explicitly in |reset()|.
class MySuperClass {
virtual void VirtualMethod() { /* do nothing */
}
};
class MyDerivedClass : public MySuperClass {
void VirtualMethod() override { /* do nothing */
}
};
static bool TestVirtualFunction() {
Maybe<MySuperClass> super;
super.emplace();
super.reset();
Maybe<MyDerivedClass> derived;
derived.emplace();
derived.reset();
// If this compiles successfully, we've passed.
return true;
}
static Maybe<int*> ReturnSomeNullptr() { return Some(nullptr); }
struct D {
explicit D(const Maybe<int*>&) {}
};
static bool TestSomeNullptrConversion() {
Maybe<int*> m1 = Some(nullptr);
MOZ_RELEASE_ASSERT(m1.isSome());
MOZ_RELEASE_ASSERT(m1);
MOZ_RELEASE_ASSERT(!*m1);
auto m2 = ReturnSomeNullptr();
MOZ_RELEASE_ASSERT(m2.isSome());
MOZ_RELEASE_ASSERT(m2);
MOZ_RELEASE_ASSERT(!*m2);
Maybe<decltype(nullptr)> m3 = Some(nullptr);
MOZ_RELEASE_ASSERT(m3.isSome());
MOZ_RELEASE_ASSERT(m3);
MOZ_RELEASE_ASSERT(*m3 == nullptr);
D d(Some(nullptr));
return true;
}
struct Base {};
struct Derived : Base {};
static Maybe<Base*> ReturnDerivedPointer() {
Derived* d = nullptr;
return Some(d);
}
struct ExplicitConstructorBasePointer {
explicit ExplicitConstructorBasePointer(const Maybe<Base*>&) {}
};
static bool TestSomePointerConversion() {
Base base;
Derived derived;
Maybe<Base*> m1 = Some(&derived);
MOZ_RELEASE_ASSERT(m1.isSome());
MOZ_RELEASE_ASSERT(m1);
MOZ_RELEASE_ASSERT(*m1 == &derived);
auto m2 = ReturnDerivedPointer();
MOZ_RELEASE_ASSERT(m2.isSome());
MOZ_RELEASE_ASSERT(m2);
MOZ_RELEASE_ASSERT(*m2 == nullptr);
Maybe<Base*> m3 = Some(&base);
MOZ_RELEASE_ASSERT(m3.isSome());
MOZ_RELEASE_ASSERT(m3);
MOZ_RELEASE_ASSERT(*m3 == &base);
auto s1 = Some(&derived);
Maybe<Base*> c1(s1);
MOZ_RELEASE_ASSERT(c1.isSome());
MOZ_RELEASE_ASSERT(c1);
MOZ_RELEASE_ASSERT(*c1 == &derived);
ExplicitConstructorBasePointer ecbp(Some(&derived));
return true;
}
struct SourceType1 {
int mTag;
operator int() const { return mTag; }
};
struct DestType {
int mTag;
Status mStatus;
DestType() : mTag(0), mStatus(eWasDefaultConstructed) {}
MOZ_IMPLICIT DestType(int aTag) : mTag(aTag), mStatus(eWasConstructed) {}
MOZ_IMPLICIT DestType(SourceType1&& aSrc)
: mTag(aSrc.mTag), mStatus(eWasMoveConstructed) {}
MOZ_IMPLICIT DestType(const SourceType1& aSrc)
: mTag(aSrc.mTag), mStatus(eWasCopyConstructed) {}
DestType& operator=(int aTag) {
mTag = aTag;
mStatus = eWasAssigned;
return *this;
}
DestType& operator=(SourceType1&& aSrc) {
mTag = aSrc.mTag;
mStatus = eWasMoveAssigned;
return *this;
}
DestType& operator=(const SourceType1& aSrc) {
mTag = aSrc.mTag;
mStatus = eWasCopyAssigned;
return *this;
}
};
struct SourceType2 {
int mTag;
operator DestType() const& {
DestType result;
result.mTag = mTag;
result.mStatus = eWasCopiedFrom;
return result;
}
operator DestType() && {
DestType result;
result.mTag = mTag;
result.mStatus = eWasMovedFrom;
return result;
}
};
static bool TestTypeConversion() {
{
Maybe<SourceType1> src = Some(SourceType1{1});
Maybe<DestType> dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 1);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasCopyConstructed);
src = Some(SourceType1{2});
dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 2);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasCopyAssigned);
}
{
Maybe<SourceType1> src = Some(SourceType1{1});
Maybe<DestType> dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasMoveConstructed);
src = Some(SourceType1{2});
dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasMoveAssigned);
}
{
Maybe<SourceType2> src = Some(SourceType2{1});
Maybe<DestType> dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 1);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasCopiedFrom);
src = Some(SourceType2{2});
dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 2);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasCopiedFrom);
}
{
Maybe<SourceType2> src = Some(SourceType2{1});
Maybe<DestType> dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasMovedFrom);
src = Some(SourceType2{2});
dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasMovedFrom);
}
{
Maybe<int> src = Some(1);
Maybe<DestType> dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && *src == 1);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasConstructed);
src = Some(2);
dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && *src == 2);
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasAssigned);
}
{
Maybe<int> src = Some(1);
Maybe<DestType> dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 1);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasConstructed);
src = Some(2);
dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && dest->mTag == 2);
MOZ_RELEASE_ASSERT(dest->mStatus == eWasAssigned);
}
{
Maybe<SourceType1> src = Some(SourceType1{1});
Maybe<int> dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 1);
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 1);
src = Some(SourceType1{2});
dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && src->mTag == 2);
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 2);
}
{
Maybe<SourceType1> src = Some(SourceType1{1});
Maybe<int> dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 1);
src = Some(SourceType1{2});
dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 2);
}
{
Maybe<size_t> src = Some(1);
Maybe<char16_t> dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && *src == 1);
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 1);
src = Some(2);
dest = src;
MOZ_RELEASE_ASSERT(src.isSome() && *src == 2);
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 2);
}
{
Maybe<size_t> src = Some(1);
Maybe<char16_t> dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 1);
src = Some(2);
dest = std::move(src);
MOZ_RELEASE_ASSERT(src.isNothing());
MOZ_RELEASE_ASSERT(dest.isSome() && *dest == 2);
}
return true;
}
static bool TestReference() {
static_assert(std::is_trivially_destructible_v<Maybe<int&>>);
static_assert(std::is_trivially_copy_constructible_v<Maybe<int&>>);
static_assert(std::is_trivially_copy_assignable_v<Maybe<int&>>);
static_assert(Maybe<int&>{}.isNothing());
static_assert(Maybe<int&>{Nothing{}}.isNothing());
{
Maybe<int&> defaultConstructed;
MOZ_RELEASE_ASSERT(defaultConstructed.isNothing());
MOZ_RELEASE_ASSERT(!defaultConstructed.isSome());
MOZ_RELEASE_ASSERT(!defaultConstructed);
}
{
Maybe<int&> nothing = Nothing();
MOZ_RELEASE_ASSERT(nothing.isNothing());
MOZ_RELEASE_ASSERT(!nothing.isSome());
MOZ_RELEASE_ASSERT(!nothing);
}
{
int foo = 42, bar = 42;
Maybe<int&> some = SomeRef(foo);
MOZ_RELEASE_ASSERT(!some.isNothing());
MOZ_RELEASE_ASSERT(some.isSome());
MOZ_RELEASE_ASSERT(some);
MOZ_RELEASE_ASSERT(&some.ref() == &foo);
MOZ_RELEASE_ASSERT(some.refEquals(foo));
MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
MOZ_RELEASE_ASSERT(!some.refEquals(bar));
MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
some.ref()++;
MOZ_RELEASE_ASSERT(43 == foo);
(*some)++;
MOZ_RELEASE_ASSERT(44 == foo);
}
{
int foo = 42, bar = 42;
Maybe<int&> some;
some.emplace(foo);
MOZ_RELEASE_ASSERT(!some.isNothing());
MOZ_RELEASE_ASSERT(some.isSome());
MOZ_RELEASE_ASSERT(some);
MOZ_RELEASE_ASSERT(&some.ref() == &foo);
MOZ_RELEASE_ASSERT(some.refEquals(foo));
MOZ_RELEASE_ASSERT(some.refEquals(SomeRef(foo)));
MOZ_RELEASE_ASSERT(!some.refEquals(Nothing()));
MOZ_RELEASE_ASSERT(!some.refEquals(bar));
MOZ_RELEASE_ASSERT(!some.refEquals(SomeRef(bar)));
some.ref()++;
MOZ_RELEASE_ASSERT(43 == foo);
}
{
Maybe<int&> defaultConstructed;
defaultConstructed.reset();
MOZ_RELEASE_ASSERT(defaultConstructed.isNothing());
MOZ_RELEASE_ASSERT(!defaultConstructed.isSome());
MOZ_RELEASE_ASSERT(!defaultConstructed);
}
{
int foo = 42;
Maybe<int&> some = SomeRef(foo);
some.reset();
MOZ_RELEASE_ASSERT(some.isNothing());
MOZ_RELEASE_ASSERT(!some.isSome());
MOZ_RELEASE_ASSERT(!some);
}
{
int foo = 42;
Maybe<int&> some = SomeRef(foo);
auto& applied = some.apply([](int& ref) { ref++; });
MOZ_RELEASE_ASSERT(&some == &applied);
MOZ_RELEASE_ASSERT(43 == foo);
}
{
Maybe<int&> nothing;
auto& applied = nothing.apply([](int& ref) { ref++; });
MOZ_RELEASE_ASSERT(¬hing == &applied);
}
{
int foo = 42;
Maybe<int&> some = SomeRef(foo);
auto mapped = some.map([](int& ref) { return &ref; });
static_assert(std::is_same_v<decltype(mapped), Maybe<int*>>);
MOZ_RELEASE_ASSERT(&foo == *mapped);
}
{
Maybe<int&> nothing;
auto mapped = nothing.map([](int& ref) { return &ref; });
MOZ_RELEASE_ASSERT(mapped.isNothing());
MOZ_RELEASE_ASSERT(!mapped.isSome());
MOZ_RELEASE_ASSERT(!mapped);
}
{
int foo = 42;
auto someRef = ToMaybeRef(&foo);
static_assert(std::is_same_v<decltype(someRef), Maybe<int&>>);
MOZ_RELEASE_ASSERT(someRef.isSome());
MOZ_RELEASE_ASSERT(&foo == &someRef.ref());
}
{
int* fooPtr = nullptr;
auto someRef = ToMaybeRef(fooPtr);
static_assert(std::is_same_v<decltype(someRef), Maybe<int&>>);
MOZ_RELEASE_ASSERT(someRef.isNothing());
}
return true;
}
static Maybe<int> IncrementAndReturnTag(BasicValue& aValue) {
gFunctionWasApplied = true;
aValue.SetTag(aValue.GetTag() + 1);
return Some(aValue.GetTag());
}
static Maybe<int> AccessValueAndReturnNothing(const BasicValue&) {
gFunctionWasApplied = true;
return Nothing();
}
static Maybe<int> AccessValueAndReturnOther(const BasicValue&) {
gFunctionWasApplied = true;
return Some(42);
}
struct IncrementAndReturnTagFunctor {
IncrementAndReturnTagFunctor() : mBy(1) {}
Maybe<int> operator()(BasicValue& aValue) {
aValue.SetTag(aValue.GetTag() + mBy.GetTag());
return Some(aValue.GetTag());
}
BasicValue mBy;
};
struct AccessValueAndReturnOtherFunctor {
explicit AccessValueAndReturnOtherFunctor(int aVal) : mBy(aVal) {}
Maybe<BasicValue> operator()() {
gFunctionWasApplied = true;
return Some(mBy);
}
BasicValue mBy;
};
static bool TestAndThen() {
// Check that andThen handles the 'Nothing' case.
gFunctionWasApplied = false;
Maybe<BasicValue> mayValue;
Maybe<int> otherValue = mayValue.andThen(&AccessValueAndReturnOther);
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue.isNothing());
// Check that andThen handles the 'Some' case.
mayValue = Some(BasicValue(1));
otherValue = mayValue.andThen(&AccessValueAndReturnNothing);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue.isNothing());
gFunctionWasApplied = false;
otherValue = mayValue.andThen(&IncrementAndReturnTag);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 2);
MOZ_RELEASE_ASSERT(*otherValue == 2);
gFunctionWasApplied = false;
otherValue = mayValue.andThen(&AccessValueAndReturnOther);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(*otherValue == 42);
// Check that andThen works with a const reference.
const Maybe<BasicValue>& mayValueCRef = mayValue;
gFunctionWasApplied = false;
otherValue = mayValueCRef.andThen(&AccessValueAndReturnOther);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(*otherValue == 42);
// Check that andThen works with functors.
IncrementAndReturnTagFunctor tagIncrementer;
MOZ_RELEASE_ASSERT(tagIncrementer.mBy.GetStatus() == eWasConstructed);
mayValue = Some(BasicValue(1));
otherValue = mayValue.andThen(tagIncrementer);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 2);
MOZ_RELEASE_ASSERT(*otherValue == 2);
MOZ_RELEASE_ASSERT(tagIncrementer.mBy.GetStatus() == eWasConstructed);
// Check that andThen works with lambda expressions.
gFunctionWasApplied = false;
mayValue = Some(BasicValue(2));
otherValue = mayValue.andThen(
[](BasicValue& aVal) { return Some(aVal.GetTag() * 2); });
MOZ_RELEASE_ASSERT(*otherValue == 4);
otherValue = otherValue.andThen([](int aVal) { return Some(aVal * 2); });
MOZ_RELEASE_ASSERT(*otherValue == 8);
otherValue = mayValueCRef.andThen([&](const BasicValue& aVal) {
gFunctionWasApplied = true;
return Some(42);
});
MOZ_RELEASE_ASSERT(gFunctionWasApplied == true);
MOZ_RELEASE_ASSERT(*otherValue == 42);
// Check that andThen can move the contained value.
mayValue = Some(BasicValue(1));
otherValue = std::move(mayValue).andThen([&](BasicValue&& aVal) {
BasicValue tmp = std::move(aVal);
return Some(tmp.GetTag());
});
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(*otherValue == 1);
return true;
}
static bool TestOrElse() {
const auto createValue = [&](int aTag) {
return [&, aTag]() -> Maybe<BasicValue> {
gFunctionWasApplied = true;
return Some(BasicValue(aTag));
};
};
// Check that orElse handles the 'Some' case.
gFunctionWasApplied = false;
Maybe<BasicValue> mayValue = Some(BasicValue(1));
Maybe<BasicValue> otherValue = mayValue.orElse(createValue(2));
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
// Check that orElse handles the 'Nothing' case.
mayValue = Nothing();
otherValue = mayValue.orElse(createValue(1));
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
gFunctionWasApplied = false;
otherValue = otherValue.orElse(createValue(2));
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
// Check that orElse works with a const reference.
mayValue = Nothing();
const Maybe<BasicValue>& mayValueCRef = mayValue;
gFunctionWasApplied = false;
otherValue = mayValueCRef.orElse(createValue(1));
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
// Check that orElse works with functors.
gFunctionWasApplied = false;
AccessValueAndReturnOtherFunctor accesser(42);
mayValue = Some(BasicValue(1));
otherValue = mayValue.orElse(accesser);
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
mayValue = Nothing();
otherValue = mayValue.orElse(accesser);
MOZ_RELEASE_ASSERT(gFunctionWasApplied);
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 42);
// Check that orElse works with lambda expressions.
gFunctionWasApplied = false;
mayValue = Nothing();
otherValue = mayValue.orElse([] { return Some(BasicValue(1)); });
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
mayValue = otherValue.orElse([] { return Some(BasicValue(2)); });
MOZ_RELEASE_ASSERT(mayValue->GetTag() == 1);
otherValue = mayValueCRef.orElse([&] {
gFunctionWasApplied = true;
return Some(BasicValue(42));
});
MOZ_RELEASE_ASSERT(!gFunctionWasApplied);
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
// Check that orElse can move the contained value.
mayValue = Some(BasicValue(1));
otherValue = std::move(mayValue).orElse([] { return Some(BasicValue(2)); });
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(otherValue->GetTag() == 1);
return true;
}
static bool TestComposedMoves() {
const auto moveAlong = [](UncopyableValue&& aValue) {
return Some(std::move(aValue));
};
const auto justNothing = []() -> Maybe<UncopyableValue> { return Nothing(); };
const auto createValue = [] { return Some(UncopyableValue()); };
// Check that andThen and orElse can propagate a non-copyable value created
// mid-chain.
Maybe<UncopyableValue> mayValue;
Maybe<UncopyableValue> movedValue = std::move(mayValue)
.andThen(moveAlong)
.orElse(createValue)
.andThen(moveAlong);
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(movedValue->GetStatus() == eWasMoveConstructed);
// Check that andThen and orElse can propagate a non-copyable value created
// pre-chain.
mayValue = Some(UncopyableValue{});
movedValue = std::move(mayValue)
.andThen(moveAlong)
.orElse(justNothing)
.andThen(moveAlong);
MOZ_RELEASE_ASSERT(mayValue.isNothing());
MOZ_RELEASE_ASSERT(movedValue->GetStatus() == eWasMoveAssigned);
// Check that andThen and orElse can propagate a reference.
{
UncopyableValue val{};
UncopyableValue otherVal{};
const auto passAlong = [](UncopyableValue& aValue) {
return SomeRef(aValue);
};
const auto fallbackToOther = [&]() { return SomeRef(otherVal); };
Maybe<UncopyableValue&> mayRef = SomeRef(val);
Maybe<UncopyableValue&> chainedRef =
mayRef.andThen(passAlong).orElse(fallbackToOther).andThen(passAlong);
MOZ_RELEASE_ASSERT(&val != &otherVal,
"Distinct values should not compare equal");
MOZ_RELEASE_ASSERT(&*mayRef == &*chainedRef,
"Chain should pass along the same reference");
}
// Check that andThen and orElse can propagate a const reference.
{
const UncopyableValue val{};
const UncopyableValue otherVal{};
const auto passAlong = [](const UncopyableValue& aValue) {
return SomeRef(aValue);
};
const auto fallbackToOther = [&]() { return SomeRef(otherVal); };
Maybe<const UncopyableValue&> mayRef = SomeRef(val);
Maybe<const UncopyableValue&> chainedRef =
mayRef.andThen(passAlong).orElse(fallbackToOther).andThen(passAlong);
MOZ_RELEASE_ASSERT(&val != &otherVal,
"Distinct values should not compare equal");
MOZ_RELEASE_ASSERT(&*mayRef == &*chainedRef,
"Chain should pass along the same reference");
}
return true;
}
// These are quasi-implementation details, but we assert them here to prevent
// backsliding to earlier times when Maybe<T> for smaller T took up more space
// than T's alignment required.
static_assert(sizeof(Maybe<char>) == 2 * sizeof(char),
"Maybe<char> shouldn't bloat at all ");
static_assert(sizeof(Maybe<bool>) <= 2 * sizeof(bool),
"Maybe<bool> shouldn't bloat");
static_assert(sizeof(Maybe<int>) <= 2 * sizeof(int),
"Maybe<int> shouldn't bloat");
static_assert(sizeof(Maybe<long>) <= 2 * sizeof(long),
"Maybe<long> shouldn't bloat");
static_assert(sizeof(Maybe<double>) <= 2 * sizeof(double),
"Maybe<double> shouldn't bloat");
static_assert(sizeof(Maybe<int&>) == sizeof(int*));
int main() {
RUN_TEST(TestBasicFeatures);
RUN_TEST(TestCopyAndMove);
RUN_TEST(TestFunctionalAccessors);
RUN_TEST(TestApply);
RUN_TEST(TestMap);
RUN_TEST(TestToMaybe);
RUN_TEST(TestComparisonOperators);
RUN_TEST(TestVirtualFunction);
RUN_TEST(TestSomeNullptrConversion);
RUN_TEST(TestSomePointerConversion);
RUN_TEST(TestTypeConversion);
RUN_TEST(TestReference);
RUN_TEST(TestAndThen);
RUN_TEST(TestOrElse);
RUN_TEST(TestComposedMoves);
return 0;
}