foundationdb/fdbclient/DatabaseContext.cpp

80 lines
3.0 KiB
C++

/*
* DatabaseContext.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "fdbclient/DatabaseContext.h"
Reference<WatchMetadata> DatabaseContext::getWatchMetadata(int64_t tenantId, KeyRef key) const {
const auto it = watchMap.find(std::make_pair(tenantId, key));
if (it == watchMap.end())
return Reference<WatchMetadata>();
return it->second;
}
void DatabaseContext::setWatchMetadata(Reference<WatchMetadata> metadata) {
const WatchMapKey key(metadata->parameters->tenant.tenantId, metadata->parameters->key);
watchMap[key] = metadata;
// NOTE Here we do *NOT* update/reset the reference count for the key, see the source code in getWatchFuture.
// Basically the reference count could be increased, or the same watch is refreshed, or the watch might be cancelled
}
int32_t DatabaseContext::increaseWatchRefCount(const int64_t tenantID, KeyRef key, const Version& version) {
const WatchMapKey mapKey(tenantID, key);
watchCounterMap[mapKey].insert(version);
return watchCounterMap[mapKey].size();
}
int32_t DatabaseContext::decreaseWatchRefCount(const int64_t tenantID, KeyRef key, const Version& version) {
const WatchMapKey mapKey(tenantID, key);
auto mapKeyIter = watchCounterMap.find(mapKey);
if (mapKeyIter == std::end(watchCounterMap)) {
// Key does not exist. The metadata might be removed by deleteWatchMetadata already.
return 0;
}
auto& versionSet = mapKeyIter->second;
auto versionIter = versionSet.find(version);
if (versionIter == std::end(versionSet)) {
// Version not found, the watch might be cleared before.
return versionSet.size();
}
versionSet.erase(versionIter);
const auto count = versionSet.size();
// The metadata might be deleted somewhere else, before calling this decreaseWatchRefCount
if (auto metadata = getWatchMetadata(tenantID, key); metadata.isValid() && versionSet.size() == 0) {
// It is a *must* to cancel the watchFutureSS manually. watchFutureSS waits for watchStorageServerResp, which
// holds a reference to the metadata. If the ACTOR is not cancelled, it indirectly holds a Future waiting for
// itself.
metadata->watchFutureSS.cancel();
deleteWatchMetadata(tenantID, key);
}
return count;
}
void DatabaseContext::deleteWatchMetadata(int64_t tenantId, KeyRef key, bool removeReferenceCount) {
const WatchMapKey mapKey(tenantId, key);
watchMap.erase(mapKey);
if (removeReferenceCount) {
watchCounterMap.erase(mapKey);
}
}