George McIntyre
116 lines
2.6 KiB
C++
116 lines
2.6 KiB
C++
/*
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* Copyright - See the COPYRIGHT that is included with this distribution.
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* pvxs is distributed subject to a Software License Agreement found
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* in file LICENSE that is included with this distribution.
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*
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* Author George S. McIntyre <george@level-n.com>, 2023
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*
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*/
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#ifndef PVXS_DBMANYLOCKER_H
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#define PVXS_DBMANYLOCKER_H
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#include <vector>
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#include <dbCommon.h>
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#include <dbLock.h>
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namespace pvxs {
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namespace ioc {
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/**
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* A lock that can lock multiple DB records simultaneously. To be used with DBManyLocker
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*
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* e.g.
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* DBManyLock lock = DBManyLock(channels);
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*/
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class DBManyLock {
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public:
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dbLocker* pLocker{};
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/**
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* Empty lock
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*/
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DBManyLock()
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:pLocker(nullptr) {
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}
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/**
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* Create a many lock from a list of channels
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*
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* @param channels the list of channels to lock
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* @param flags the lock flags to be passed on to dbLockerAlloc()
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*/
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explicit DBManyLock(const std::vector<dbCommon*>& channels, unsigned flags = 0) {
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pLocker = dbLockerAlloc(channels.data(), channels.size(), flags);
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if (!pLocker) {
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throw std::invalid_argument("Failed to create locker");
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}
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}
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/**
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* When the lock goes out of scope, then free the lock
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*/
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~DBManyLock() {
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if (pLocker) {
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dbLockerFree(pLocker);
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pLocker = nullptr;
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}
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}
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explicit operator dbLocker*() const {
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return pLocker;
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}
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DBManyLock(DBManyLock&& other) noexcept
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:pLocker(other.pLocker) {
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other.pLocker = nullptr;
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}
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DBManyLock& operator=(DBManyLock&& other) noexcept {
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if (pLocker) {
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dbLockerFree(pLocker);
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}
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pLocker = other.pLocker;
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other.pLocker = nullptr;
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return *this;
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}
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// Prevent copy construction and assignment
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DBManyLock(const DBManyLock&) = delete;
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DBManyLock& operator=(const DBManyLock& other) = delete;
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};
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/**
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* To lock access to multiple DB records simultaneously.
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* Use by creating a new object. It will lock the records locked by the constructor parameter while the object is
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* in scope. First you need to create a lock using the DBManyLock().
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*
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* e.g.
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* {
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* DBManyLock lock = DBManyLock(channels);
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* DBManyLocker F(lock); // Lock all channels
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* for ( auto& pDbChannel: channels ) {
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* IOCSource::put(pDbChannel, ...);
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* }
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* ...
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* } // Unlocked
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*/
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class DBManyLocker {
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public:
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const DBManyLock& lock;
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explicit DBManyLocker(DBManyLock& L)
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:lock(L) {
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dbScanLockMany(lock.pLocker);
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}
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~DBManyLocker() {
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dbScanUnlockMany(lock.pLocker);
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}
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};
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} // pvxs
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} // ioc
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#endif //PVXS_DBMANYLOCKER_H
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