rocksdb/utilities/object_registry.cc
Mark Rambacher cfcf045acc The ObjectRegistry class replaces the Registrar and NewCustomObjects.… (#5293)
Summary:
The ObjectRegistry class replaces the Registrar and NewCustomObjects.  Objects are registered with the registry by Type (the class must implement the static const char *Type() method).

This change is necessary for a few reasons:
- By having a class (rather than static template instances), the class can be passed between compilation units, meaning that objects could be registered and shared from a dynamic library with an executable.
- By having a class with instances, different units could have different objects registered.  This could be useful if, for example, one Option allowed for a dynamic library and one did not.

When combined with some other PRs (being able to load shared libraries, a Configurable interface to configure objects to/from string), this code will allow objects in external shared libraries to be added to a RocksDB image at run-time, rather than requiring every new extension to be built into the main library and called explicitly by every program.

Test plan (on riversand963's  devserver)
```
$COMPILE_WITH_ASAN=1 make -j32 all && sleep 1 && make check
```
All tests pass.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5293

Differential Revision: D16363396

Pulled By: riversand963

fbshipit-source-id: fbe4acb615bfc11103eef40a0b288845791c0180
2019-07-23 17:13:05 -07:00

88 lines
2.8 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 {
#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 {
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) {
auto &entries = entries_[type];
entries.emplace_back(std::move(entry));
}
void ObjectLibrary::Dump(Logger *logger) const {
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>();
return instance;
}
std::shared_ptr<ObjectRegistry> ObjectRegistry::NewInstance() {
std::shared_ptr<ObjectRegistry> instance = std::make_shared<ObjectRegistry>();
return instance;
}
ObjectRegistry::ObjectRegistry() {
libraries_.push_back(ObjectLibrary::Default());
}
// 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;
}
}
return nullptr;
}
void ObjectRegistry::Dump(Logger *logger) const {
for (auto iter = libraries_.crbegin(); iter != libraries_.crend(); ++iter) {
iter->get()->Dump(logger);
}
}
#endif // ROCKSDB_LITE
} // namespace rocksdb