+++ /dev/null
-// Copyright (c) 2011-present, Facebook, Inc. 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).
-
-#pragma once
-#ifndef ROCKSDB_LITE
-
-#include <array>
-#include "rocksdb/slice.h"
-#include "db/dbformat.h"
-#include "table/plain_table_reader.h"
-
-namespace rocksdb {
-
-class WritableFile;
-struct ParsedInternalKey;
-struct PlainTableReaderFileInfo;
-enum PlainTableEntryType : unsigned char;
-
-// Helper class to write out a key to an output file
-// Actual data format of the key is documented in plain_table_factory.h
-class PlainTableKeyEncoder {
- public:
- explicit PlainTableKeyEncoder(EncodingType encoding_type,
- uint32_t user_key_len,
- const SliceTransform* prefix_extractor,
- size_t index_sparseness)
- : encoding_type_((prefix_extractor != nullptr) ? encoding_type : kPlain),
- fixed_user_key_len_(user_key_len),
- prefix_extractor_(prefix_extractor),
- index_sparseness_((index_sparseness > 1) ? index_sparseness : 1),
- key_count_for_prefix_(0) {}
- // key: the key to write out, in the format of internal key.
- // file: the output file to write out
- // offset: offset in the file. Needs to be updated after appending bytes
- // for the key
- // meta_bytes_buf: buffer for extra meta bytes
- // meta_bytes_buf_size: offset to append extra meta bytes. Will be updated
- // if meta_bytes_buf is updated.
- Status AppendKey(const Slice& key, WritableFileWriter* file, uint64_t* offset,
- char* meta_bytes_buf, size_t* meta_bytes_buf_size);
-
- // Return actual encoding type to be picked
- EncodingType GetEncodingType() { return encoding_type_; }
-
- private:
- EncodingType encoding_type_;
- uint32_t fixed_user_key_len_;
- const SliceTransform* prefix_extractor_;
- const size_t index_sparseness_;
- size_t key_count_for_prefix_;
- IterKey pre_prefix_;
-};
-
-class PlainTableFileReader {
- public:
- explicit PlainTableFileReader(const PlainTableReaderFileInfo* _file_info)
- : file_info_(_file_info), num_buf_(0) {}
- // In mmaped mode, the results point to mmaped area of the file, which
- // means it is always valid before closing the file.
- // In non-mmap mode, the results point to an internal buffer. If the caller
- // makes another read call, the results may not be valid. So callers should
- // make a copy when needed.
- // In order to save read calls to files, we keep two internal buffers:
- // the first read and the most recent read. This is efficient because it
- // columns these two common use cases:
- // (1) hash index only identify one location, we read the key to verify
- // the location, and read key and value if it is the right location.
- // (2) after hash index checking, we identify two locations (because of
- // hash bucket conflicts), we binary search the two location to see
- // which one is what we need and start to read from the location.
- // These two most common use cases will be covered by the two buffers
- // so that we don't need to re-read the same location.
- // Currently we keep a fixed size buffer. If a read doesn't exactly fit
- // the buffer, we replace the second buffer with the location user reads.
- //
- // If return false, status code is stored in status_.
- bool Read(uint32_t file_offset, uint32_t len, Slice* out) {
- if (file_info_->is_mmap_mode) {
- assert(file_offset + len <= file_info_->data_end_offset);
- *out = Slice(file_info_->file_data.data() + file_offset, len);
- return true;
- } else {
- return ReadNonMmap(file_offset, len, out);
- }
- }
-
- // If return false, status code is stored in status_.
- bool ReadNonMmap(uint32_t file_offset, uint32_t len, Slice* output);
-
- // *bytes_read = 0 means eof. false means failure and status is saved
- // in status_. Not directly returning Status to save copying status
- // object to map previous performance of mmap mode.
- inline bool ReadVarint32(uint32_t offset, uint32_t* output,
- uint32_t* bytes_read);
-
- bool ReadVarint32NonMmap(uint32_t offset, uint32_t* output,
- uint32_t* bytes_read);
-
- Status status() const { return status_; }
-
- const PlainTableReaderFileInfo* file_info() { return file_info_; }
-
- private:
- const PlainTableReaderFileInfo* file_info_;
-
- struct Buffer {
- Buffer() : buf_start_offset(0), buf_len(0), buf_capacity(0) {}
- std::unique_ptr<char[]> buf;
- uint32_t buf_start_offset;
- uint32_t buf_len;
- uint32_t buf_capacity;
- };
-
- // Keep buffers for two recent reads.
- std::array<std::unique_ptr<Buffer>, 2> buffers_;
- uint32_t num_buf_;
- Status status_;
-
- Slice GetFromBuffer(Buffer* buf, uint32_t file_offset, uint32_t len);
-};
-
-// A helper class to decode keys from input buffer
-// Actual data format of the key is documented in plain_table_factory.h
-class PlainTableKeyDecoder {
- public:
- explicit PlainTableKeyDecoder(const PlainTableReaderFileInfo* file_info,
- EncodingType encoding_type,
- uint32_t user_key_len,
- const SliceTransform* prefix_extractor)
- : file_reader_(file_info),
- encoding_type_(encoding_type),
- prefix_len_(0),
- fixed_user_key_len_(user_key_len),
- prefix_extractor_(prefix_extractor),
- in_prefix_(false) {}
- // Find the next key.
- // start: char array where the key starts.
- // limit: boundary of the char array
- // parsed_key: the output of the result key
- // internal_key: if not null, fill with the output of the result key in
- // un-parsed format
- // bytes_read: how many bytes read from start. Output
- // seekable: whether key can be read from this place. Used when building
- // indexes. Output.
- Status NextKey(uint32_t start_offset, ParsedInternalKey* parsed_key,
- Slice* internal_key, Slice* value, uint32_t* bytes_read,
- bool* seekable = nullptr);
-
- Status NextKeyNoValue(uint32_t start_offset, ParsedInternalKey* parsed_key,
- Slice* internal_key, uint32_t* bytes_read,
- bool* seekable = nullptr);
-
- PlainTableFileReader file_reader_;
- EncodingType encoding_type_;
- uint32_t prefix_len_;
- uint32_t fixed_user_key_len_;
- Slice saved_user_key_;
- IterKey cur_key_;
- const SliceTransform* prefix_extractor_;
- bool in_prefix_;
-
- private:
- Status NextPlainEncodingKey(uint32_t start_offset,
- ParsedInternalKey* parsed_key,
- Slice* internal_key, uint32_t* bytes_read,
- bool* seekable = nullptr);
- Status NextPrefixEncodingKey(uint32_t start_offset,
- ParsedInternalKey* parsed_key,
- Slice* internal_key, uint32_t* bytes_read,
- bool* seekable = nullptr);
- Status ReadInternalKey(uint32_t file_offset, uint32_t user_key_size,
- ParsedInternalKey* parsed_key, uint32_t* bytes_read,
- bool* internal_key_valid, Slice* internal_key);
- inline Status DecodeSize(uint32_t start_offset,
- PlainTableEntryType* entry_type, uint32_t* key_size,
- uint32_t* bytes_read);
-};
-
-} // namespace rocksdb
-
-#endif // ROCKSDB_LITE
projects / ceph.git / blobdiff