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// 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
#include <limits>
#include <string>
#include <vector>
#include "options/db_options.h"
#include "port/port.h"
#include "rocksdb/comparator.h"
#include "rocksdb/iterator.h"
#include "rocksdb/slice.h"
#include "rocksdb/status.h"
#include "rocksdb/utilities/write_batch_with_index.h"
namespace rocksdb {
class MergeContext;
struct Options;
// Key used by skip list, as the binary searchable index of WriteBatchWithIndex.
struct WriteBatchIndexEntry {
WriteBatchIndexEntry(size_t o, uint32_t c, size_t ko, size_t ksz)
: offset(o),
search_key(nullptr) {}
WriteBatchIndexEntry(const Slice* sk, uint32_t c)
: offset(0),
search_key(sk) {}
// If this flag appears in the offset, it indicates a key that is smaller
// than any other entry for the same column family
static const size_t kFlagMin = port::kMaxSizet;
size_t offset; // offset of an entry in write batch's string buffer.
uint32_t column_family; // column family of the entry.
size_t key_offset; // offset of the key in write batch's string buffer.
size_t key_size; // size of the key.
const Slice* search_key; // if not null, instead of reading keys from
// write batch, use it to compare. This is used
// for lookup key.
class ReadableWriteBatch : public WriteBatch {
explicit ReadableWriteBatch(size_t reserved_bytes = 0, size_t max_bytes = 0)
: WriteBatch(reserved_bytes, max_bytes) {}
// Retrieve some information from a write entry in the write batch, given
// the start offset of the write entry.
Status GetEntryFromDataOffset(size_t data_offset, WriteType* type, Slice* Key,
Slice* value, Slice* blob, Slice* xid) const;
class WriteBatchEntryComparator {
WriteBatchEntryComparator(const Comparator* _default_comparator,
const ReadableWriteBatch* write_batch)
: default_comparator_(_default_comparator), write_batch_(write_batch) {}
// Compare a and b. Return a negative value if a is less than b, 0 if they
// are equal, and a positive value if a is greater than b
int operator()(const WriteBatchIndexEntry* entry1,
const WriteBatchIndexEntry* entry2) const;
int CompareKey(uint32_t column_family, const Slice& key1,
const Slice& key2) const;
void SetComparatorForCF(uint32_t column_family_id,
const Comparator* comparator) {
if (column_family_id >= cf_comparators_.size()) {
cf_comparators_.resize(column_family_id + 1, nullptr);
cf_comparators_[column_family_id] = comparator;
const Comparator* default_comparator() { return default_comparator_; }
const Comparator* default_comparator_;
std::vector<const Comparator*> cf_comparators_;
const ReadableWriteBatch* write_batch_;
class WriteBatchWithIndexInternal {
enum Result { kFound, kDeleted, kNotFound, kMergeInProgress, kError };
// If batch contains a value for key, store it in *value and return kFound.
// If batch contains a deletion for key, return Deleted.
// If batch contains Merge operations as the most recent entry for a key,
// and the merge process does not stop (not reaching a value or delete),
// prepend the current merge operands to *operands,
// and return kMergeInProgress
// If batch does not contain this key, return kNotFound
// Else, return kError on error with error Status stored in *s.
static WriteBatchWithIndexInternal::Result GetFromBatch(
const ImmutableDBOptions& ioptions, WriteBatchWithIndex* batch,
ColumnFamilyHandle* column_family, const Slice& key,
MergeContext* merge_context, WriteBatchEntryComparator* cmp,
std::string* value, bool overwrite_key, Status* s);
} // namespace rocksdb
#endif // !ROCKSDB_LITE