1 // Copyright (c) 2011 The LevelDB Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. See the AUTHORS file for names of contributors. 4 // 5 // TableBuilder provides the interface used to build a Table 6 // (an immutable and sorted map from keys to values). 7 // 8 // Multiple threads can invoke const methods on a TableBuilder without 9 // external synchronization, but if any of the threads may call a 10 // non-const method, all threads accessing the same TableBuilder must use 11 // external synchronization. 12 13 #ifndef STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_ 14 #define STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_ 15 16 #include <stdint.h> 17 #include "leveldb/options.h" 18 #include "leveldb/status.h" 19 20 namespace leveldb { 21 22 class BlockBuilder; 23 class BlockHandle; 24 class WritableFile; 25 26 class TableBuilder { 27 public: 28 // Create a builder that will store the contents of the table it is 29 // building in *file. Does not close the file. It is up to the 30 // caller to close the file after calling Finish(). 31 TableBuilder(const Options& options, WritableFile* file); 32 33 // REQUIRES: Either Finish() or Abandon() has been called. 34 ~TableBuilder(); 35 36 // Change the options used by this builder. Note: only some of the 37 // option fields can be changed after construction. If a field is 38 // not allowed to change dynamically and its value in the structure 39 // passed to the constructor is different from its value in the 40 // structure passed to this method, this method will return an error 41 // without changing any fields. 42 Status ChangeOptions(const Options& options); 43 44 // Add key,value to the table being constructed. 45 // REQUIRES: key is after any previously added key according to comparator. 46 // REQUIRES: Finish(), Abandon() have not been called 47 void Add(const Slice& key, const Slice& value); 48 49 // Advanced operation: flush any buffered key/value pairs to file. 50 // Can be used to ensure that two adjacent entries never live in 51 // the same data block. Most clients should not need to use this method. 52 // REQUIRES: Finish(), Abandon() have not been called 53 void Flush(); 54 55 // Return non-ok iff some error has been detected. 56 Status status() const; 57 58 // Finish building the table. Stops using the file passed to the 59 // constructor after this function returns. 60 // REQUIRES: Finish(), Abandon() have not been called 61 Status Finish(); 62 63 // Indicate that the contents of this builder should be abandoned. Stops 64 // using the file passed to the constructor after this function returns. 65 // If the caller is not going to call Finish(), it must call Abandon() 66 // before destroying this builder. 67 // REQUIRES: Finish(), Abandon() have not been called 68 void Abandon(); 69 70 // Number of calls to Add() so far. 71 uint64_t NumEntries() const; 72 73 // Size of the file generated so far. If invoked after a successful 74 // Finish() call, returns the size of the final generated file. 75 uint64_t FileSize() const; 76 77 private: 78 bool ok() const { return status().ok(); } 79 void WriteBlock(BlockBuilder* block, BlockHandle* handle); 80 void WriteRawBlock(const Slice& data, CompressionType, BlockHandle* handle); 81 82 struct Rep; 83 Rep* rep_; 84 85 // No copying allowed 86 TableBuilder(const TableBuilder&); 87 void operator=(const TableBuilder&); 88 }; 89 90 } // namespace leveldb 91 92 #endif // STORAGE_LEVELDB_INCLUDE_TABLE_BUILDER_H_ 93
