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platform_system_core
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Merge "Add expected<void,E>"

This commit is contained in:
Treehugger Robot 2019-06-07 07:17:47 +00:00 committed by Gerrit Code Review
parent a850fb2d1e b2a85c4333
commit bb1b83e325
4 changed files with 371 additions and 7 deletions
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149
base/expected_test.cpp
View File

@ -29,6 +29,7 @@ typedef expected<int, int> exp_int;
typedef expected<double, double> exp_double;
typedef expected<std::string, std::string> exp_string;
typedef expected<std::pair<std::string, int>, int> exp_pair;
typedef expected<void, int> exp_void;
struct T {
int a;
@ -59,6 +60,9 @@ TEST(Expected, testDefaultConstructible) {
exp_complex e2;
EXPECT_TRUE(e2.has_value());
EXPECT_EQ(T(0,0), e2.value());
exp_void e3;
EXPECT_TRUE(e3.has_value());
}
TEST(Expected, testCopyConstructible) {
@ -69,6 +73,11 @@ TEST(Expected, testCopyConstructible) {
EXPECT_TRUE(e2.has_value());
EXPECT_EQ(0, e.value());
EXPECT_EQ(0, e2.value());
exp_void e3;
exp_void e4 = e3;
EXPECT_TRUE(e3.has_value());
EXPECT_TRUE(e4.has_value());
}
TEST(Expected, testMoveConstructible) {
@ -87,6 +96,11 @@ TEST(Expected, testMoveConstructible) {
EXPECT_TRUE(e4.has_value());
EXPECT_EQ("", e3.value()); // e3 is moved
EXPECT_EQ("hello", e4.value());
exp_void e5;
exp_void e6 = std::move(e5);
EXPECT_TRUE(e5.has_value());
EXPECT_TRUE(e6.has_value());
}
TEST(Expected, testCopyConstructibleFromConvertibleType) {
@ -114,11 +128,13 @@ TEST(Expected, testConstructibleFromValue) {
exp_double e2 = 5.5f;
exp_string e3 = std::string("hello");
exp_complex e4 = T(10, 20);
exp_void e5 = {};
EXPECT_TRUE(e.has_value());
EXPECT_TRUE(e2.has_value());
EXPECT_TRUE(e3.has_value());
EXPECT_TRUE(e4.has_value());
EXPECT_TRUE(e5.has_value());
EXPECT_EQ(3, e.value());
EXPECT_EQ(5.5f, e2.value());
EXPECT_EQ("hello", e3.value());
@ -154,25 +170,33 @@ TEST(Expected, testConstructibleFromUnexpected) {
exp_string::unexpected_type unexp3 = unexpected(std::string("error"));
exp_string e3 = unexp3;
exp_void::unexpected_type unexp4 = unexpected(10);
exp_void e4 = unexp4;
EXPECT_FALSE(e.has_value());
EXPECT_FALSE(e2.has_value());
EXPECT_FALSE(e3.has_value());
EXPECT_FALSE(e4.has_value());
EXPECT_EQ(10, e.error());
EXPECT_EQ(10.5f, e2.error());
EXPECT_EQ("error", e3.error());
EXPECT_EQ(10, e4.error());
}
TEST(Expected, testMoveConstructibleFromUnexpected) {
exp_int e = unexpected(10);
exp_double e2 = unexpected(10.5f);
exp_string e3 = unexpected(std::string("error"));
exp_void e4 = unexpected(10);
EXPECT_FALSE(e.has_value());
EXPECT_FALSE(e2.has_value());
EXPECT_FALSE(e3.has_value());
EXPECT_FALSE(e4.has_value());
EXPECT_EQ(10, e.error());
EXPECT_EQ(10.5f, e2.error());
EXPECT_EQ("error", e3.error());
EXPECT_EQ(10, e4.error());
}
TEST(Expected, testConstructibleByForwarding) {
@ -188,6 +212,9 @@ TEST(Expected, testConstructibleByForwarding) {
EXPECT_TRUE(e3.has_value());
EXPECT_EQ("hello",e3->first);
EXPECT_EQ(30,e3->second);
exp_void e4({});
EXPECT_TRUE(e4.has_value());
}
TEST(Expected, testDestructible) {
@ -217,6 +244,14 @@ TEST(Expected, testAssignable) {
EXPECT_EQ(20, e3.value());
EXPECT_EQ(20, e4.value());
exp_void e5 = unexpected(10);
ASSERT_FALSE(e5.has_value());
exp_void e6;
e5 = e6;
EXPECT_TRUE(e5.has_value());
EXPECT_TRUE(e6.has_value());
}
TEST(Expected, testAssignableFromValue) {
@ -231,6 +266,11 @@ TEST(Expected, testAssignableFromValue) {
exp_string e3 = "hello";
e3 = "world";
EXPECT_EQ("world", e3.value());
exp_void e4 = unexpected(10);
ASSERT_FALSE(e4.has_value());
e4 = {};
EXPECT_TRUE(e4.has_value());
}
TEST(Expected, testAssignableFromUnexpected) {
@ -248,6 +288,11 @@ TEST(Expected, testAssignableFromUnexpected) {
e3 = unexpected("world");
EXPECT_FALSE(e3.has_value());
EXPECT_EQ("world", e3.error());
exp_void e4 = {};
e4 = unexpected(10);
EXPECT_FALSE(e4.has_value());
EXPECT_EQ(10, e4.error());
}
TEST(Expected, testAssignableFromMovedValue) {
@ -285,6 +330,11 @@ TEST(Expected, testEmplace) {
EXPECT_EQ(10.5f, t.b);
EXPECT_EQ(3, exp.value().a);
EXPECT_EQ(10.5, exp.value().b);
exp_void e = unexpected(10);
ASSERT_FALSE(e.has_value());
e.emplace();
EXPECT_TRUE(e.has_value());
}
TEST(Expected, testSwapExpectedExpected) {
@ -296,6 +346,13 @@ TEST(Expected, testSwapExpectedExpected) {
EXPECT_TRUE(e2.has_value());
EXPECT_EQ(20, e.value());
EXPECT_EQ(10, e2.value());
exp_void e3;
exp_void e4;
e3.swap(e4);
EXPECT_TRUE(e3.has_value());
EXPECT_TRUE(e4.has_value());
}
TEST(Expected, testSwapUnexpectedUnexpected) {
@ -306,6 +363,14 @@ TEST(Expected, testSwapUnexpectedUnexpected) {
EXPECT_FALSE(e2.has_value());
EXPECT_EQ(20, e.error());
EXPECT_EQ(10, e2.error());
exp_void e3 = unexpected(10);
exp_void e4 = unexpected(20);
e3.swap(e4);
EXPECT_FALSE(e3.has_value());
EXPECT_FALSE(e4.has_value());
EXPECT_EQ(20, e3.error());
EXPECT_EQ(10, e4.error());
}
TEST(Expected, testSwapExpectedUnepected) {
@ -316,6 +381,13 @@ TEST(Expected, testSwapExpectedUnepected) {
EXPECT_TRUE(e2.has_value());
EXPECT_EQ(30, e.error());
EXPECT_EQ(10, e2.value());
exp_void e3;
exp_void e4 = unexpected(10);
e3.swap(e4);
EXPECT_FALSE(e3.has_value());
EXPECT_TRUE(e4.has_value());
EXPECT_EQ(10, e3.error());
}
TEST(Expected, testDereference) {
@ -361,6 +433,13 @@ TEST(Expected, testSameValues) {
EXPECT_TRUE(e2 == e);
EXPECT_FALSE(e != e2);
EXPECT_FALSE(e2 != e);
exp_void e3;
exp_void e4;
EXPECT_TRUE(e3 == e4);
EXPECT_TRUE(e4 == e3);
EXPECT_FALSE(e3 != e4);
EXPECT_FALSE(e4 != e3);
}
TEST(Expected, testDifferentValues) {
@ -379,6 +458,13 @@ TEST(Expected, testValueWithError) {
EXPECT_FALSE(e2 == e);
EXPECT_TRUE(e != e2);
EXPECT_TRUE(e2 != e);
exp_void e3;
exp_void e4 = unexpected(10);
EXPECT_FALSE(e3 == e4);
EXPECT_FALSE(e4 == e3);
EXPECT_TRUE(e3 != e4);
EXPECT_TRUE(e4 != e3);
}
TEST(Expected, testSameErrors) {
@ -388,6 +474,13 @@ TEST(Expected, testSameErrors) {
EXPECT_TRUE(e2 == e);
EXPECT_FALSE(e != e2);
EXPECT_FALSE(e2 != e);
exp_void e3 = unexpected(10);
exp_void e4 = unexpected(10);
EXPECT_TRUE(e3 == e4);
EXPECT_TRUE(e4 == e3);
EXPECT_FALSE(e3 != e4);
EXPECT_FALSE(e4 != e3);
}
TEST(Expected, testDifferentErrors) {
@ -397,6 +490,13 @@ TEST(Expected, testDifferentErrors) {
EXPECT_FALSE(e2 == e);
EXPECT_TRUE(e != e2);
EXPECT_TRUE(e2 != e);
exp_void e3 = unexpected(10);
exp_void e4 = unexpected(20);
EXPECT_FALSE(e3 == e4);
EXPECT_FALSE(e4 == e3);
EXPECT_TRUE(e3 != e4);
EXPECT_TRUE(e4 != e3);
}
TEST(Expected, testCompareWithSameValue) {
@ -424,6 +524,13 @@ TEST(Expected, testCompareWithSameError) {
EXPECT_TRUE(error == e);
EXPECT_FALSE(e != error);
EXPECT_FALSE(error != e);
exp_void e2 = unexpected(10);
exp_void::unexpected_type error2 = 10;
EXPECT_TRUE(e2 == error2);
EXPECT_TRUE(error2 == e2);
EXPECT_FALSE(e2 != error2);
EXPECT_FALSE(error2 != e2);
}
TEST(Expected, testCompareWithDifferentError) {
@ -433,6 +540,32 @@ TEST(Expected, testCompareWithDifferentError) {
EXPECT_FALSE(error == e);
EXPECT_TRUE(e != error);
EXPECT_TRUE(error != e);
exp_void e2 = unexpected(10);
exp_void::unexpected_type error2 = 20;
EXPECT_FALSE(e2 == error2);
EXPECT_FALSE(error2 == e2);
EXPECT_TRUE(e2 != error2);
EXPECT_TRUE(error2 != e2);
}
TEST(Expected, testCompareDifferentType) {
expected<int,int> e = 10;
expected<int32_t, int> e2 = 10;
EXPECT_TRUE(e == e2);
e2 = 20;
EXPECT_FALSE(e == e2);
expected<std::string_view,int> e3 = "hello";
expected<std::string,int> e4 = "hello";
EXPECT_TRUE(e3 == e4);
e4 = "world";
EXPECT_FALSE(e3 == e4);
expected<void,int> e5;
expected<int,int> e6 = 10;
EXPECT_FALSE(e5 == e6);
EXPECT_FALSE(e6 == e5);
}
TEST(Expected, testDivideExample) {
@ -478,6 +611,22 @@ TEST(Expected, testPair) {
EXPECT_EQ("yes", r->first);
}
TEST(Expected, testVoid) {
auto test = [](bool ok) -> exp_void {
if (ok) {
return {};
} else {
return unexpected(10);
}
};
auto r = test(true);
EXPECT_TRUE(r);
r = test(false);
EXPECT_FALSE(r);
EXPECT_EQ(10, r.error());
}
// copied from result_test.cpp
struct ConstructorTracker {
static size_t constructor_called;

196
base/include/android-base/expected.h
View File

@ -412,13 +412,7 @@ constexpr bool operator==(const expected<T1, E1>& x, const expected<T2, E2>& y)
template<class T1, class E1, class T2, class E2>
constexpr bool operator!=(const expected<T1, E1>& x, const expected<T2, E2>& y) {
if (x.has_value() != y.has_value()) {
return true;
} else if (!x.has_value()) {
return x.error() != y.error();
} else {
return *x != *y;
}
return !(x == y);
}
// comparison with T
@ -457,6 +451,194 @@ constexpr bool operator!=(const unexpected<E2>& x, const expected<T1, E1>& y) {
return y.has_value() || (x.value() != y.error());
}
template<class E>
class _NODISCARD_ expected<void, E> {
public:
using value_type = void;
using error_type = E;
using unexpected_type = unexpected<E>;
// constructors
constexpr expected() = default;
constexpr expected(const expected& rhs) = default;
constexpr expected(expected&& rhs) noexcept = default;
template<class U, class G _ENABLE_IF(
std::is_void_v<U> &&
std::is_convertible_v<const G&, E> /* non-explicit */
)>
constexpr expected(const expected<U, G>& rhs) {
if (!rhs.has_value()) var_ = unexpected(rhs.error());
}
template<class U, class G _ENABLE_IF(
std::is_void_v<U> &&
!std::is_convertible_v<const G&, E> /* explicit */
)>
constexpr explicit expected(const expected<U, G>& rhs) {
if (!rhs.has_value()) var_ = unexpected(rhs.error());
}
template<class U, class G _ENABLE_IF(
std::is_void_v<U> &&
std::is_convertible_v<const G&&, E> /* non-explicit */
)>
constexpr expected(expected<U, G>&& rhs) {
if (!rhs.has_value()) var_ = unexpected(std::move(rhs.error()));
}
template<class U, class G _ENABLE_IF(
std::is_void_v<U> &&
!std::is_convertible_v<const G&&, E> /* explicit */
)>
constexpr explicit expected(expected<U, G>&& rhs) {
if (!rhs.has_value()) var_ = unexpected(std::move(rhs.error()));
}
template<class G = E _ENABLE_IF(
std::is_constructible_v<E, const G&> &&
std::is_convertible_v<const G&, E> /* non-explicit */
)>
constexpr expected(const unexpected<G>& e)
: var_(std::in_place_index<1>, e.value()) {}
template<class G = E _ENABLE_IF(
std::is_constructible_v<E, const G&> &&
!std::is_convertible_v<const G&, E> /* explicit */
)>
constexpr explicit expected(const unexpected<G>& e)
: var_(std::in_place_index<1>, E(e.value())) {}
template<class G = E _ENABLE_IF(
std::is_constructible_v<E, G&&> &&
std::is_convertible_v<G&&, E> /* non-explicit */
)>
constexpr expected(unexpected<G>&& e)
: var_(std::in_place_index<1>, std::move(e.value())) {}
template<class G = E _ENABLE_IF(
std::is_constructible_v<E, G&&> &&
!std::is_convertible_v<G&&, E> /* explicit */
)>
constexpr explicit expected(unexpected<G>&& e)
: var_(std::in_place_index<1>, E(std::move(e.value()))) {}
template<class... Args _ENABLE_IF(
sizeof...(Args) == 0
)>
constexpr explicit expected(std::in_place_t, Args&&...) {}
template<class... Args _ENABLE_IF(
std::is_constructible_v<E, Args...>
)>
constexpr explicit expected(unexpect_t, Args&&... args)
: var_(unexpected_type(std::forward<Args>(args)...)) {}
template<class U, class... Args _ENABLE_IF(
std::is_constructible_v<E, std::initializer_list<U>&, Args...>
)>
constexpr explicit expected(unexpect_t, std::initializer_list<U> il, Args&&... args)
: var_(unexpected_type(il, std::forward<Args>(args)...)) {}
// destructor
~expected() = default;
// assignment
// Note: SFNAIE doesn't work here because assignment operator should be
// non-template. We could workaround this by defining a templated parent class
// having the assignment operator. This incomplete implementation however
// doesn't allow us to copy assign expected<T,E> even when T is non-copy
// assignable. The copy assignment will fail by the underlying std::variant
// anyway though the error message won't be clear.
expected& operator=(const expected& rhs) = default;
// Note for SFNAIE above applies to here as well
expected& operator=(expected&& rhs) = default;
template<class G = E>
expected& operator=(const unexpected<G>& rhs) {
var_ = rhs;
return *this;
}
template<class G = E _ENABLE_IF(
std::is_nothrow_move_constructible_v<G> &&
std::is_move_assignable_v<G>
)>
expected& operator=(unexpected<G>&& rhs) {
var_ = std::move(rhs);
return *this;
}
// modifiers
void emplace() {
var_ = std::monostate();
}
// swap
template<typename = std::enable_if_t<
std::is_swappable_v<E>>
>
void swap(expected& rhs) noexcept(std::is_nothrow_move_constructible_v<E>) {
var_.swap(rhs.var_);
}
// observers
constexpr explicit operator bool() const noexcept { return has_value(); }
constexpr bool has_value() const noexcept { return var_.index() == 0; }
constexpr void value() const& { if (!has_value()) std::get<0>(var_); }
constexpr const E& error() const& { return std::get<unexpected_type>(var_).value(); }
constexpr E& error() & { return std::get<unexpected_type>(var_).value(); }
constexpr const E&& error() const&& { return std::move(std::get<unexpected_type>(var_)).value(); }
constexpr E&& error() && { return std::move(std::get<unexpected_type>(var_)).value(); }
// expected equality operators
template<class E1, class E2>
friend constexpr bool operator==(const expected<void, E1>& x, const expected<void, E2>& y);
// Specialized algorithms
template<class T1, class E1>
friend void swap(expected<T1, E1>&, expected<T1, E1>&) noexcept;
private:
std::variant<std::monostate, unexpected_type> var_;
};
template<class E1, class E2>
constexpr bool operator==(const expected<void, E1>& x, const expected<void, E2>& y) {
if (x.has_value() != y.has_value()) {
return false;
} else if (!x.has_value()) {
return x.error() == y.error();
} else {
return true;
}
}
template<class T1, class E1, class E2>
constexpr bool operator==(const expected<T1, E1>& x, const expected<void, E2>& y) {
if (x.has_value() != y.has_value()) {
return false;
} else if (!x.has_value()) {
return x.error() == y.error();
} else {
return false;
}
}
template<class E1, class T2, class E2>
constexpr bool operator==(const expected<void, E1>& x, const expected<T2, E2>& y) {
if (x.has_value() != y.has_value()) {
return false;
} else if (!x.has_value()) {
return x.error() == y.error();
} else {
return false;
}
}
template<class E>
class unexpected {
public:

8
base/include/android-base/result.h
View File

@ -98,6 +98,14 @@ struct ResultError {
int code_;
};
inline bool operator==(const ResultError& lhs, const ResultError& rhs) {
return lhs.message() == rhs.message() && lhs.code() == rhs.code();
}
inline bool operator!=(const ResultError& lhs, const ResultError& rhs) {
return !(lhs == rhs);
}
inline std::ostream& operator<<(std::ostream& os, const ResultError& t) {
os << t.message();
return os;

25
base/result_test.cpp
View File

@ -70,6 +70,31 @@ TEST(result, result_success_rvalue) {
EXPECT_EQ(Success(), MakeRvalueSuccessResult().value());
}
TEST(result, result_void) {
Result<void> ok = {};
EXPECT_TRUE(ok);
ok.value(); // should not crash
ASSERT_DEATH(ok.error(), "");
Result<void> fail = Error() << "failure" << 1;
EXPECT_FALSE(fail);
EXPECT_EQ("failure1", fail.error().message());
EXPECT_EQ(0, fail.error().code());
EXPECT_TRUE(ok != fail);
ASSERT_DEATH(fail.value(), "");
auto test = [](bool ok) -> Result<void> {
if (ok) return {};
else return Error() << "failure" << 1;
};
EXPECT_TRUE(test(true));
EXPECT_FALSE(test(false));
test(true).value(); // should not crash
ASSERT_DEATH(test(true).error(), "");
ASSERT_DEATH(test(false).value(), "");
EXPECT_EQ("failure1", test(false).error().message());
}
TEST(result, result_error) {
Result<Success> result = Error() << "failure" << 1;
ASSERT_FALSE(result);