rocksdb/util/mock_time_env.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include "rocksdb/env.h"
namespace rocksdb {
class MockTimeEnv : public EnvWrapper {
public:
explicit MockTimeEnv(Env* base) : EnvWrapper(base) {}
virtual Status GetCurrentTime(int64_t* time) override {
assert(time != nullptr);
assert(current_time_ <=
static_cast<uint64_t>(std::numeric_limits<int64_t>::max()));
*time = static_cast<int64_t>(current_time_);
return Status::OK();
}
virtual uint64_t NowMicros() override {
assert(current_time_ <= std::numeric_limits<uint64_t>::max() / 1000000);
return current_time_ * 1000000;
}
virtual uint64_t NowNanos() override {
assert(current_time_ <= std::numeric_limits<uint64_t>::max() / 1000000000);
return current_time_ * 1000000000;
}
Update RepeatableThreadTest with MockTimeEnv (#5107) Summary: **This PR updates RepeatableThread::wait, breaking some tests on OS X. The rest of the PR fixes the tests on OS X.** `RepeatableThreadTest.MockEnvTest` uses `MockTimeEnv` and `RepeatableThread`. If `RepeatableThread::wait` calls `TimedWait` with a time smaller than or equal to the current (real) time, `TimedWait` returns immediately on certain platforms, e.g. OS X. #4560 addresses this issue by replacing `TimedWait` with `Wait` in test. This fixes the test but makes test/production code diverge, which is not optimal for test coverage. This PR proposes an alternative fix which unifies test and production code path for `RepeatableThread::wait`. We obtain the current (real) time in seconds and add 10 extra seconds to ensure that `RepeatableThread::wait` invokes `TimedWait` with a time greater than (real) current time. This is to prevent the `TimedWait` function from returning immediately without sleeping and releasing the mutex. If `TimedWait` returns immediately, the mutex will not be released, and `RepeatableThread::TEST_WaitForRun` never has a chance to execute the callback which, in this case, updates the result returned by `mock_env->NowMicros()`. Consequently, `RepeatableThread::wait` cannot break out of the loop, causing test to hang. The extra 10 seconds is a best-effort approach because there seems no reliable and deterministic way to provide the aforementioned guarantee. By the time `RepeatableThread::wait` is called, there is no guarantee that the `delay + mock_env->NowMicros()` will be greater than the current real time. However, 10 seconds should be sufficient in most cases. We will keep an eye for possible flakiness of this test. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5107 Differential Revision: D14680885 Pulled By: riversand963 fbshipit-source-id: d1ecbe10e1dacd110bd464cd01e188bfee72b89e
2019-03-29 18:03:02 +01:00
uint64_t RealNowMicros() { return target()->NowMicros(); }
void set_current_time(uint64_t time) {
assert(time >= current_time_);
current_time_ = time;
}
private:
std::atomic<uint64_t> current_time_{0};
};
} // namespace rocksdb