mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-14 22:56:12 -04:00
Janusz Sobczak
7a99b5e0a3
ExceptionOr<T>::ok() returns true if the value is set. This can be misleading
for boolean types.
ExceptionOr<bool> result = SomeFunction();
if (result.ok()) {
if (result.result() {
// Case 1: SomeFunction returned true
} else {
// Case 2: SomeFunction returned false
} else {
// Case 3: SomeFunction returned an exception
}
It's easy to overlook case 2.
The specialized ExceptionOr<bool>::ok() returns false in Case 2, which allows
us to write:
if (result) {
// SomeFunction returned true
} else {
// SomeFunction returned false or an exception
// result.GetException() can be used if we need to handle different exceptions
// differenty
}
PiperOrigin-RevId: 544715641
68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "internal/platform/count_down_latch.h"
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#include "gtest/gtest.h"
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#include "internal/platform/single_thread_executor.h"
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namespace nearby {
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namespace {
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TEST(CountDownLatch, ConstructorDestructorWorks) { CountDownLatch latch(1); }
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TEST(CountDownLatch, LatchAwaitCanWait) {
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CountDownLatch latch(1);
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SingleThreadExecutor executor;
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std::atomic_bool done = false;
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executor.Execute([&done, &latch]() {
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done = true;
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latch.CountDown();
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});
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latch.Await();
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EXPECT_TRUE(done);
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}
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TEST(CountDownLatch, LatchExtraCountDownIgnored) {
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CountDownLatch latch(1);
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SingleThreadExecutor executor;
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std::atomic_bool done = false;
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executor.Execute([&done, &latch]() {
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done = true;
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latch.CountDown();
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latch.CountDown();
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latch.CountDown();
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});
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latch.Await();
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EXPECT_TRUE(done);
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}
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TEST(CountDownLatch, LatchAwaitWithTimeoutCanExpire) {
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CountDownLatch latch(1);
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SingleThreadExecutor executor;
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auto response = latch.Await(absl::Milliseconds(100));
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EXPECT_FALSE(response);
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}
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TEST(CountDownLatch, InitialCountZero_AwaitDoesNotBlock) {
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CountDownLatch latch(0);
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auto response = latch.Await();
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EXPECT_TRUE(response.Ok());
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}
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} // namespace
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} // namespace nearby
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