Merge changes from topic "or_return" (e060580c) · Commits · e / os / android_system_core

init/builtins.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -117,7 +117,7 @@ class ErrorIgnoreEnoent {
		android::base::GetMinimumLogSeverity() > android::base::DEBUG) {}

		template <typename T>
		operator android::base::expected<T, ResultError<int>>() {
		operator android::base::expected<T, ResultError<android::base::Errno>>() {
		if (ignore_error_) {
		return {};
		}

libutils/Android.bp

+10 −5

Original line number	Diff line number	Diff line
		@@ -28,16 +28,18 @@ cc_library_headers {
		min_sdk_version: "apex_inherit",

		header_libs: [
		"liblog_headers",
		"libsystem_headers",
		"libbase_headers",
		"libcutils_headers",
		"liblog_headers",
		"libprocessgroup_headers",
		"libsystem_headers",
		],
		export_header_lib_headers: [
		"liblog_headers",
		"libsystem_headers",
		"libbase_headers",
		"libcutils_headers",
		"liblog_headers",
		"libprocessgroup_headers",
		"libsystem_headers",
		],
		export_include_dirs: ["include"],

		@@ -299,13 +301,14 @@ cc_test {

		srcs: [
		"BitSet_test.cpp",
		"Errors_test.cpp",
		"FileMap_test.cpp",
		"LruCache_test.cpp",
		"Mutex_test.cpp",
		"SharedBuffer_test.cpp",
		"Singleton_test.cpp",
		"String8_test.cpp",
		"String16_test.cpp",
		"String8_test.cpp",
		"StrongPointer_test.cpp",
		"Timers_test.cpp",
		"Unicode_test.cpp",
		@@ -364,6 +367,7 @@ cc_test_library {
		"-Wall",
		"-Werror",
		],
		header_libs: ["libutils_headers"],
		}

		cc_test_library {
		@@ -376,6 +380,7 @@ cc_test_library {
		"-Werror",
		],
		shared_libs: ["libutils_test_singleton1"],
		header_libs: ["libutils_headers"],
		}

		cc_benchmark {

libutils/Errors_test.cpp

0 → 100644

+110 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2021 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#include "utils/ErrorsMacros.h"

		#include <android-base/result.h>

		#include <gtest/gtest.h>

		using namespace android;

		using android::base::Error;
		using android::base::Result;

		status_t success_or_fail(bool success) {
		if (success)
		return OK;
		else
		return PERMISSION_DENIED;
		}

		TEST(errors, unwrap_or_return) {
		auto f = [](bool success, int* val) -> status_t {
		OR_RETURN(success_or_fail(success));
		*val = 10;
		return OK;
		};

		int val;
		status_t s = f(true, &val);
		EXPECT_EQ(OK, s);
		EXPECT_EQ(10, val);

		val = 0; // reset
		status_t q = f(false, &val);
		EXPECT_EQ(PERMISSION_DENIED, q);
		EXPECT_EQ(0, val);
		}

		TEST(errors, unwrap_or_return_result) {
		auto f = [](bool success) -> Result<std::string, StatusT> {
		OR_RETURN(success_or_fail(success));
		return "hello";
		};

		auto r = f(true);
		EXPECT_TRUE(r.ok());
		EXPECT_EQ("hello", *r);

		auto s = f(false);
		EXPECT_FALSE(s.ok());
		EXPECT_EQ(PERMISSION_DENIED, s.error().code());
		EXPECT_EQ("PERMISSION_DENIED", s.error().message());
		}

		TEST(errors, unwrap_or_return_result_int) {
		auto f = [](bool success) -> Result<int, StatusT> {
		OR_RETURN(success_or_fail(success));
		return 10;
		};

		auto r = f(true);
		EXPECT_TRUE(r.ok());
		EXPECT_EQ(10, *r);

		auto s = f(false);
		EXPECT_FALSE(s.ok());
		EXPECT_EQ(PERMISSION_DENIED, s.error().code());
		EXPECT_EQ("PERMISSION_DENIED", s.error().message());
		}

		TEST(errors, unwrap_or_fatal) {
		OR_FATAL(success_or_fail(true));

		EXPECT_DEATH(OR_FATAL(success_or_fail(false)), "PERMISSION_DENIED");
		}

		TEST(errors, result_in_status) {
		auto f = [](bool success) -> Result<std::string, StatusT> {
		if (success)
		return "OK";
		else
		return Error<StatusT>(PERMISSION_DENIED) << "custom error message";
		};

		auto g = [&](bool success) -> status_t {
		std::string val = OR_RETURN(f(success));
		EXPECT_EQ("OK", val);
		return OK;
		};

		status_t a = g(true);
		EXPECT_EQ(OK, a);

		status_t b = g(false);
		EXPECT_EQ(PERMISSION_DENIED, b);
		}

libutils/include/utils/ErrorsMacros.h

0 → 100644

+86 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2021 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#pragma once

		#include "Errors.h"

		// It would have been better if this file (ErrorsMacros.h) is entirely in utils/Errors.h. However
		// that is infeasible as some (actually many) are using utils/Errors.h via the implicit include path
		// `system/core/include` [1]. Since such users are not guaranteed to specify the dependency to
		// libbase_headers, the following headers from libbase_headers can't be found.
		// [1] build/soong/cc/config/global.go#commonGlobalIncludes
		#include <android-base/errors.h>
		#include <android-base/result.h>

		#include <assert.h>

		namespace android {

		// StatusT is a wrapper class for status_t. Use this type instead of status_t when instantiating
		// Result<T, E> and Error<E> template classes. This is required to distinguish status_t from
		// other integer-based error code types like errno, and also to provide utility functions like
		// print().
		struct StatusT {
		StatusT() : val_(OK) {}
		StatusT(status_t s) : val_(s) {}
		const status_t& value() const { return val_; }
		operator status_t() const { return val_; }
		std::string print() const { return statusToString(val_); }

		status_t val_;
		};

		namespace base {

		// Specialization of android::base::OkOrFail<V> for V = status_t. This is used to use the OR_RETURN
		// and OR_FATAL macros with statements that yields a value of status_t. See android-base/errors.h
		// for the detailed contract.
		template <>
		struct OkOrFail<status_t> {
		// Tests if status_t is a success value of not.
		static bool IsOk(const status_t& s) { return s == OK; }

		// Unwrapping status_t in the success case is just asserting that it is actually a success.
		// We don't return OK because it would be redundant.
		static void Unwrap([[maybe_unused]] status_t&& s) { assert(IsOk(s)); }

		// Consumes status_t when it's a fail value
		static OkOrFail<status_t> Fail(status_t&& s) {
		assert(!IsOk(s));
		return OkOrFail<status_t>{s};
		}
		status_t val_;

		// And converts back into status_t. This is used when OR_RETURN is used in a function whose
		// return type is status_t.
		operator status_t() && { return val_; }

		// Or converts into Result<T, StatusT>. This is used when OR_RETURN is used in a function whose
		// return type is Result<T, StatusT>.
		template <typename T, typename = std::enable_if_t<!std::is_same_v<T, status_t>>>
		operator Result<T, StatusT>() && {
		return Error<StatusT>(std::move(val_));
		}

		operator Result<int, StatusT>() && { return Error<StatusT>(std::move(val_)); }

		// String representation of the error value.
		static std::string ErrorMessage(const status_t& s) { return statusToString(s); }
		};

		} // namespace base
		} // namespace android