rocksdb/db/column_family.h
2014-01-24 18:40:05 -08:00

88 lines
3.1 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include "rocksdb/options.h"
#include <unordered_map>
#include <string>
#include <vector>
namespace rocksdb {
class Version;
class VersionSet;
// column family metadata
struct ColumnFamilyData {
uint32_t id;
std::string name;
Version* dummy_versions; // Head of circular doubly-linked list of versions.
Version* current; // == dummy_versions->prev_
ColumnFamilyOptions options;
ColumnFamilyData(uint32_t id, const std::string& name,
Version* dummy_versions, const ColumnFamilyOptions& options);
~ColumnFamilyData();
};
class ColumnFamilySet {
public:
class iterator {
public:
explicit iterator(
std::unordered_map<uint32_t, ColumnFamilyData*>::iterator itr)
: itr_(itr) {}
iterator& operator++() {
++itr_;
return *this;
}
bool operator!=(const iterator& other) { return this->itr_ != other.itr_; }
ColumnFamilyData* operator*() { return itr_->second; }
private:
std::unordered_map<uint32_t, ColumnFamilyData*>::iterator itr_;
};
ColumnFamilySet();
~ColumnFamilySet();
ColumnFamilyData* GetDefault() const;
// GetColumnFamily() calls return nullptr if column family is not found
ColumnFamilyData* GetColumnFamily(uint32_t id) const;
bool Exists(uint32_t id);
bool Exists(const std::string& name);
uint32_t GetID(const std::string& name);
// this call will return the next available column family ID. it guarantees
// that there is no column family with id greater than or equal to the
// returned value in the current running instance. It does not, however,
// guarantee that the returned ID is unique accross RocksDB restarts.
// For example, if a client adds a column family 6 and then drops it,
// after a restart, we might reuse column family 6 ID.
uint32_t GetNextColumnFamilyID();
ColumnFamilyData* CreateColumnFamily(const std::string& name, uint32_t id,
Version* dummy_version,
const ColumnFamilyOptions& options);
void DropColumnFamily(uint32_t id);
iterator begin() { return iterator(column_family_data_.begin()); }
iterator end() { return iterator(column_family_data_.end()); }
private:
std::unordered_map<std::string, uint32_t> column_families_;
std::unordered_map<uint32_t, ColumnFamilyData*> column_family_data_;
// we need to keep them alive because we still can't control the lifetime of
// all of column family data members (options for example)
std::vector<ColumnFamilyData*> droppped_column_families_;
uint32_t max_column_family_;
};
} // namespace rocksdb