1cf11317ca
This is the clang-tidy lint 'google-explicit-constructor'. There's a whole bunch of breakage that was introduced by this, and we had to opt out a few types of this (esp. the string formatting crap). In some cases minor other changes have been done to keep the code working, instead of converting between types (e.g. an explicit comparison operator implementation for nix::Pid). Change-Id: I12e1ca51a6bc2c882dba81a2526b9729d26988e7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/1832 Tested-by: BuildkiteCI Reviewed-by: kanepyork <rikingcoding@gmail.com> Reviewed-by: glittershark <grfn@gws.fyi>
84 lines
1.8 KiB
C++
84 lines
1.8 KiB
C++
#pragma once
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#include <cassert>
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#include <condition_variable>
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#include <cstdlib>
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#include <mutex>
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namespace nix {
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/* This template class ensures synchronized access to a value of type
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T. It is used as follows:
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struct Data { int x; ... };
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Sync<Data> data;
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{
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auto data_(data.lock());
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data_->x = 123;
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}
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Here, "data" is automatically unlocked when "data_" goes out of
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scope.
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*/
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template <class T, class M = std::mutex>
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class Sync {
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private:
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M mutex;
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T data;
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public:
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Sync() {}
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explicit Sync(const T& data) : data(data) {}
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explicit Sync(T&& data) noexcept : data(std::move(data)) {}
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class Lock {
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private:
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Sync* s;
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std::unique_lock<M> lk;
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friend Sync;
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explicit Lock(Sync* s) : s(s), lk(s->mutex) {}
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public:
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Lock(Lock&& l) : s(l.s) { abort(); }
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Lock(const Lock& l) = delete;
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~Lock() {}
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T* operator->() { return &s->data; }
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T& operator*() { return s->data; }
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void wait(std::condition_variable& cv) {
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assert(s);
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cv.wait(lk);
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}
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template <class Rep, class Period>
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std::cv_status wait_for(
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std::condition_variable& cv,
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const std::chrono::duration<Rep, Period>& duration) {
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assert(s);
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return cv.wait_for(lk, duration);
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}
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template <class Rep, class Period, class Predicate>
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bool wait_for(std::condition_variable& cv,
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const std::chrono::duration<Rep, Period>& duration,
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Predicate pred) {
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assert(s);
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return cv.wait_for(lk, duration, pred);
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}
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template <class Clock, class Duration>
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std::cv_status wait_until(
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std::condition_variable& cv,
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const std::chrono::time_point<Clock, Duration>& duration) {
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assert(s);
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return cv.wait_until(lk, duration);
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}
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};
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Lock lock() { return Lock(this); }
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};
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} // namespace nix
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