7c5e583a27
Summary: I created a separate class ColumnFamilySet to keep track of column families. Before we did this in VersionSet and I believe this approach is cleaner. Let me know if you have any comments. I will commit tomorrow. Test Plan: make check Reviewers: dhruba, haobo, kailiu, sdong CC: leveldb Differential Revision: https://reviews.facebook.net/D15357
88 lines
3.1 KiB
C++
88 lines
3.1 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/options.h"
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#include <map>
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#include <string>
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#include <vector>
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namespace rocksdb {
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class Version;
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class VersionSet;
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// column family metadata
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struct ColumnFamilyData {
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uint32_t id;
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std::string name;
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Version* dummy_versions; // Head of circular doubly-linked list of versions.
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Version* current; // == dummy_versions->prev_
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ColumnFamilyOptions options;
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ColumnFamilyData(uint32_t id, const std::string& name,
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Version* dummy_versions, const ColumnFamilyOptions& options);
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~ColumnFamilyData();
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};
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class ColumnFamilySet {
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public:
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class iterator {
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public:
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explicit iterator(
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std::unordered_map<uint32_t, ColumnFamilyData*>::iterator itr)
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: itr_(itr) {}
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iterator& operator++() {
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++itr_;
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return *this;
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}
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bool operator!=(const iterator& other) { return this->itr_ != other.itr_; }
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ColumnFamilyData* operator*() { return itr_->second; }
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private:
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std::unordered_map<uint32_t, ColumnFamilyData*>::iterator itr_;
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};
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ColumnFamilySet();
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~ColumnFamilySet();
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ColumnFamilyData* GetDefault() const;
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// GetColumnFamily() calls return nullptr if column family is not found
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ColumnFamilyData* GetColumnFamily(uint32_t id) const;
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bool Exists(uint32_t id);
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bool Exists(const std::string& name);
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uint32_t GetID(const std::string& name);
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// this call will return the next available column family ID. it guarantees
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// that there is no column family with id greater than or equal to the
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// returned value in the current running instance. It does not, however,
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// guarantee that the returned ID is unique accross RocksDB restarts.
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// For example, if a client adds a column family 6 and then drops it,
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// after a restart, we might reuse column family 6 ID.
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uint32_t GetNextColumnFamilyID();
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ColumnFamilyData* CreateColumnFamily(const std::string& name, uint32_t id,
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Version* dummy_version,
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const ColumnFamilyOptions& options);
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void DropColumnFamily(uint32_t id);
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iterator begin() { return iterator(column_family_data_.begin()); }
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iterator end() { return iterator(column_family_data_.end()); }
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private:
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std::unordered_map<std::string, uint32_t> column_families_;
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std::unordered_map<uint32_t, ColumnFamilyData*> column_family_data_;
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// we need to keep them alive because we still can't control the lifetime of
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// all of column family data members (options for example)
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std::vector<ColumnFamilyData*> droppped_column_families_;
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uint32_t max_column_family_;
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};
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} // namespace rocksdb
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