51 rindas
978 B
51 rindas
978 B
//
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// Created by 马也驰 on 2024/12/28.
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//
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#ifndef LEVELDB_SHARED_LOCK_H
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#define LEVELDB_SHARED_LOCK_H
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#include <mutex>
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class SharedLock {
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public:
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SharedLock() : read_count_(0) {}
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public:
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void soft_lock() {
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write_latch_.lock();
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read_count_latch_.lock();
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if (!read_count_) {
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read_latch_.lock();
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}
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read_count_ ++;
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read_count_latch_.unlock();
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write_latch_.unlock();
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}
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void soft_unlock() {
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read_count_latch_.lock();
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read_count_ --;
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if (!read_count_) {
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read_latch_.unlock();
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}
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read_count_latch_.unlock();
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}
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void hard_lock() {
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read_latch_.lock();
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write_latch_.lock();
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read_latch_.unlock();
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}
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void hard_unlock() {
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write_latch_.unlock();
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}
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private:
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std::mutex read_latch_; // indicate if any read is proceeding
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std::mutex read_count_latch_;
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volatile size_t read_count_;
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std::mutex write_latch_; // indicate if any write is proceeding
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};
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#endif // LEVELDB_SHARED_LOCK_H
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