rocksdb/utilities/object_registry.cc
Jay Zhuang c4a503f3df Fix an race condition during multiple DB opening (#8574)
Summary:
ObjectLibrary is shared between multiple DB instances, the
Register() could have race condition.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8574

Test Plan: pass the failed test

Reviewed By: ajkr

Differential Revision: D29855096

Pulled By: jay-zhuang

fbshipit-source-id: 541eed0bd495d2c963d858d81e7eabf1ba16153c
2021-07-22 13:43:06 -07:00

114 lines
3.5 KiB
C++

// Copyright (c) Facebook, Inc. and its affiliates. 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).
#include "rocksdb/utilities/object_registry.h"
#include "logging/logging.h"
#include "rocksdb/env.h"
namespace ROCKSDB_NAMESPACE {
#ifndef ROCKSDB_LITE
// Looks through the "type" factories for one that matches "name".
// If found, returns the pointer to the Entry matching this name.
// Otherwise, nullptr is returned
const ObjectLibrary::Entry *ObjectLibrary::FindEntry(
const std::string &type, const std::string &name) const {
std::unique_lock<std::mutex> lock(mu_);
auto entries = entries_.find(type);
if (entries != entries_.end()) {
for (const auto &entry : entries->second) {
if (entry->matches(name)) {
return entry.get();
}
}
}
return nullptr;
}
void ObjectLibrary::AddEntry(const std::string &type,
std::unique_ptr<Entry> &entry) {
std::unique_lock<std::mutex> lock(mu_);
auto &entries = entries_[type];
entries.emplace_back(std::move(entry));
}
size_t ObjectLibrary::GetFactoryCount(size_t *types) const {
std::unique_lock<std::mutex> lock(mu_);
*types = entries_.size();
size_t factories = 0;
for (const auto &e : entries_) {
factories += e.second.size();
}
return factories;
}
void ObjectLibrary::Dump(Logger *logger) const {
std::unique_lock<std::mutex> lock(mu_);
for (const auto &iter : entries_) {
ROCKS_LOG_HEADER(logger, " Registered factories for type[%s] ",
iter.first.c_str());
bool printed_one = false;
for (const auto &e : iter.second) {
ROCKS_LOG_HEADER(logger, "%c %s", (printed_one) ? ',' : ':',
e->Name().c_str());
printed_one = true;
}
}
ROCKS_LOG_HEADER(logger, "\n");
}
// Returns the Default singleton instance of the ObjectLibrary
// This instance will contain most of the "standard" registered objects
std::shared_ptr<ObjectLibrary> &ObjectLibrary::Default() {
static std::shared_ptr<ObjectLibrary> instance =
std::make_shared<ObjectLibrary>("default");
return instance;
}
std::shared_ptr<ObjectRegistry> ObjectRegistry::Default() {
static std::shared_ptr<ObjectRegistry> instance(
new ObjectRegistry(ObjectLibrary::Default()));
return instance;
}
std::shared_ptr<ObjectRegistry> ObjectRegistry::NewInstance() {
return std::make_shared<ObjectRegistry>(Default());
}
std::shared_ptr<ObjectRegistry> ObjectRegistry::NewInstance(
const std::shared_ptr<ObjectRegistry> &parent) {
return std::make_shared<ObjectRegistry>(parent);
}
// Searches (from back to front) the libraries looking for the
// an entry that matches this pattern.
// Returns the entry if it is found, and nullptr otherwise
const ObjectLibrary::Entry *ObjectRegistry::FindEntry(
const std::string &type, const std::string &name) const {
for (auto iter = libraries_.crbegin(); iter != libraries_.crend(); ++iter) {
const auto *entry = iter->get()->FindEntry(type, name);
if (entry != nullptr) {
return entry;
}
}
if (parent_ != nullptr) {
return parent_->FindEntry(type, name);
} else {
return nullptr;
}
}
void ObjectRegistry::Dump(Logger *logger) const {
for (auto iter = libraries_.crbegin(); iter != libraries_.crend(); ++iter) {
iter->get()->Dump(logger);
}
if (parent_ != nullptr) {
parent_->Dump(logger);
}
}
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE