Merge "Remove Result<Success> in favor of Result<void>" (bc1ccde8) · Commits · e / os / android_system_core

base/include/android-base/result.h

+2 −7

Original line number	Diff line number	Diff line
		@@ -28,9 +28,8 @@
		// from when the error occurred. ResultError can be used in an ostream directly to print its
		// string value.
		//
		// Success is a typedef that aids in creating Result<T> that do not contain a return value.
		// Result<Success> is the correct return type for a function that either returns successfully or
		// returns an error value. Returning Success() from a function that returns Result<Success> is the
		// Result<void> is the correct return type for a function that either returns successfully or
		// returns an error value. Returning {} from a function that returns Result<void> is the
		// correct way to indicate that a function without a return type has completed successfully.
		//
		// A successful Result<T> is constructed implicitly from any type that can be implicitly converted
		@@ -164,9 +163,5 @@ inline Error ErrnoError() {
		template <typename T>
		using Result = android::base::expected<T, ResultError>;

		// Usage: `Result<Success>` as a result type that doesn't contain a value.
		// Use `return {}` or `return Success()` to return with success.
		using Success = std::monostate;

		} // namespace base
		} // namespace android

base/result_test.cpp

+11 −34

Original line number	Diff line number	Diff line
		@@ -49,27 +49,6 @@ TEST(result, result_accessors_rvalue) {
		EXPECT_EQ('s', Result<std::string>("success")->data()[0]);
		}

		TEST(result, result_success) {
		Result<Success> result = Success();
		ASSERT_TRUE(result);
		ASSERT_TRUE(result.has_value());

		EXPECT_EQ(Success(), *result);
		EXPECT_EQ(Success(), result.value());
		}

		TEST(result, result_success_rvalue) {
		// Success() doesn't actually create a Result<Success> object, but rather an object that can be
		// implicitly constructed into a Result<Success> object.

		auto MakeRvalueSuccessResult = []() -> Result<Success> { return Success(); };
		ASSERT_TRUE(MakeRvalueSuccessResult());
		ASSERT_TRUE(MakeRvalueSuccessResult().has_value());

		EXPECT_EQ(Success(), *MakeRvalueSuccessResult());
		EXPECT_EQ(Success(), MakeRvalueSuccessResult().value());
		}

		TEST(result, result_void) {
		Result<void> ok = {};
		EXPECT_TRUE(ok);
		@@ -96,7 +75,7 @@ TEST(result, result_void) {
		}

		TEST(result, result_error) {
		Result<Success> result = Error() << "failure" << 1;
		Result<void> result = Error() << "failure" << 1;
		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());

		@@ -105,7 +84,7 @@ TEST(result, result_error) {
		}

		TEST(result, result_error_empty) {
		Result<Success> result = Error();
		Result<void> result = Error();
		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());

		@@ -120,7 +99,7 @@ TEST(result, result_error_rvalue) {
		// definition will not know what the type, T, of the underlying Result<T> object that it would
		// create is.

		auto MakeRvalueErrorResult = []() -> Result<Success> { return Error() << "failure" << 1; };
		auto MakeRvalueErrorResult = []() -> Result<void> { return Error() << "failure" << 1; };
		ASSERT_FALSE(MakeRvalueErrorResult());
		ASSERT_FALSE(MakeRvalueErrorResult().has_value());

		@@ -131,7 +110,7 @@ TEST(result, result_error_rvalue) {
		TEST(result, result_errno_error) {
		constexpr int test_errno = 6;
		errno = test_errno;
		Result<Success> result = ErrnoError() << "failure" << 1;
		Result<void> result = ErrnoError() << "failure" << 1;

		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());
		@@ -143,7 +122,7 @@ TEST(result, result_errno_error) {
		TEST(result, result_errno_error_no_text) {
		constexpr int test_errno = 6;
		errno = test_errno;
		Result<Success> result = ErrnoError();
		Result<void> result = ErrnoError();

		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());
		@@ -154,7 +133,7 @@ TEST(result, result_errno_error_no_text) {

		TEST(result, result_error_from_other_result) {
		auto error_text = "test error"s;
		Result<Success> result = Error() << error_text;
		Result<void> result = Error() << error_text;

		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());
		@@ -170,7 +149,7 @@ TEST(result, result_error_from_other_result) {

		TEST(result, result_error_through_ostream) {
		auto error_text = "test error"s;
		Result<Success> result = Error() << error_text;
		Result<void> result = Error() << error_text;

		ASSERT_FALSE(result);
		ASSERT_FALSE(result.has_value());
		@@ -188,7 +167,7 @@ TEST(result, result_errno_error_through_ostream) {
		auto error_text = "test error"s;
		constexpr int test_errno = 6;
		errno = 6;
		Result<Success> result = ErrnoError() << error_text;
		Result<void> result = ErrnoError() << error_text;

		errno = 0;

		@@ -306,9 +285,7 @@ TEST(result, no_copy_on_return) {
		// constructor. This is done with by disabling the forwarding reference constructor if its first
		// and only type is Result<T>.
		TEST(result, result_result_with_success) {
		auto return_result_result_with_success = []() -> Result<Result<Success>> {
		return Result<Success>();
		};
		auto return_result_result_with_success = []() -> Result<Result<void>> { return Result<void>(); };
		auto result = return_result_result_with_success();
		ASSERT_TRUE(result);
		ASSERT_TRUE(*result);
		@@ -318,8 +295,8 @@ TEST(result, result_result_with_success) {
		}

		TEST(result, result_result_with_failure) {
		auto return_result_result_with_error = []() -> Result<Result<Success>> {
		return Result<Success>(ResultError("failure string", 6));
		auto return_result_result_with_error = []() -> Result<Result<void>> {
		return Result<void>(ResultError("failure string", 6));
		};
		auto result = return_result_result_with_error();
		ASSERT_TRUE(result);