Du kannst nicht mehr als 25 Themen auswählen
Themen müssen entweder mit einem Buchstaben oder einer Ziffer beginnen. Sie können Bindestriche („-“) enthalten und bis zu 35 Zeichen lang sein.
150 Zeilen
4.1 KiB
150 Zeilen
4.1 KiB
// 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.
|
|
//
|
|
// WriteBatch::rep_ :=
|
|
// sequence: fixed64
|
|
// count: fixed32
|
|
// data: record[count]
|
|
// record :=
|
|
// kTypeValue varstring varstring |
|
|
// kTypeDeletion varstring
|
|
// varstring :=
|
|
// len: varint32
|
|
// data: uint8[len]
|
|
|
|
#include "leveldb/write_batch.h"
|
|
|
|
#include "db/dbformat.h"
|
|
#include "db/memtable.h"
|
|
#include "db/write_batch_internal.h"
|
|
#include "leveldb/db.h"
|
|
#include "util/coding.h"
|
|
|
|
namespace leveldb {
|
|
|
|
// WriteBatch header has an 8-byte sequence number followed by a 4-byte count.
|
|
static const size_t kHeader = 12;
|
|
|
|
WriteBatch::WriteBatch() { Clear(); }
|
|
|
|
WriteBatch::~WriteBatch() = default;
|
|
|
|
WriteBatch::Handler::~Handler() = default;
|
|
|
|
void WriteBatch::Clear() {
|
|
rep_.clear();
|
|
rep_.resize(kHeader);
|
|
}
|
|
|
|
size_t WriteBatch::ApproximateSize() const { return rep_.size(); }
|
|
|
|
Status WriteBatch::Iterate(Handler* handler) const {
|
|
Slice input(rep_);
|
|
if (input.size() < kHeader) {
|
|
return Status::Corruption("malformed WriteBatch (too small)");
|
|
}
|
|
|
|
input.remove_prefix(kHeader);
|
|
Slice key, value;
|
|
int found = 0;
|
|
while (!input.empty()) {
|
|
found++;
|
|
char tag = input[0];
|
|
input.remove_prefix(1);
|
|
switch (tag) {
|
|
case kTypeValue:
|
|
if (GetLengthPrefixedSlice(&input, &key) &&
|
|
GetLengthPrefixedSlice(&input, &value)) {
|
|
handler->Put(key, value);
|
|
} else {
|
|
return Status::Corruption("bad WriteBatch Put");
|
|
}
|
|
break;
|
|
case kTypeDeletion:
|
|
if (GetLengthPrefixedSlice(&input, &key)) {
|
|
handler->Delete(key);
|
|
} else {
|
|
return Status::Corruption("bad WriteBatch Delete");
|
|
}
|
|
break;
|
|
default:
|
|
return Status::Corruption("unknown WriteBatch tag");
|
|
}
|
|
}
|
|
if (found != WriteBatchInternal::Count(this)) {
|
|
return Status::Corruption("WriteBatch has wrong count");
|
|
} else {
|
|
return Status::OK();
|
|
}
|
|
}
|
|
|
|
int WriteBatchInternal::Count(const WriteBatch* b) {
|
|
return DecodeFixed32(b->rep_.data() + 8);
|
|
}
|
|
|
|
void WriteBatchInternal::SetCount(WriteBatch* b, int n) {
|
|
EncodeFixed32(&b->rep_[8], n);
|
|
}
|
|
|
|
SequenceNumber WriteBatchInternal::Sequence(const WriteBatch* b) {
|
|
return SequenceNumber(DecodeFixed64(b->rep_.data()));
|
|
}
|
|
|
|
void WriteBatchInternal::SetSequence(WriteBatch* b, SequenceNumber seq) {
|
|
EncodeFixed64(&b->rep_[0], seq);
|
|
}
|
|
|
|
void WriteBatch::Put(const Slice& key, const Slice& value) {
|
|
WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
|
|
rep_.push_back(static_cast<char>(kTypeValue));
|
|
PutLengthPrefixedSlice(&rep_, key);
|
|
PutLengthPrefixedSlice(&rep_, value);
|
|
}
|
|
|
|
void WriteBatch::Delete(const Slice& key) {
|
|
WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
|
|
rep_.push_back(static_cast<char>(kTypeDeletion));
|
|
PutLengthPrefixedSlice(&rep_, key);
|
|
}
|
|
|
|
void WriteBatch::Append(const WriteBatch& source) {
|
|
WriteBatchInternal::Append(this, &source);
|
|
}
|
|
|
|
namespace {
|
|
class MemTableInserter : public WriteBatch::Handler {
|
|
public:
|
|
SequenceNumber sequence_;
|
|
MemTable* mem_;
|
|
|
|
void Put(const Slice& key, const Slice& value) override {
|
|
mem_->Add(sequence_, kTypeValue, key, value);
|
|
sequence_++;
|
|
}
|
|
void Delete(const Slice& key) override {
|
|
mem_->Add(sequence_, kTypeDeletion, key, Slice());
|
|
sequence_++;
|
|
}
|
|
};
|
|
} // namespace
|
|
|
|
Status WriteBatchInternal::InsertInto(const WriteBatch* b, MemTable* memtable) {
|
|
MemTableInserter inserter;
|
|
inserter.sequence_ = WriteBatchInternal::Sequence(b);
|
|
inserter.mem_ = memtable;
|
|
return b->Iterate(&inserter);
|
|
}
|
|
|
|
void WriteBatchInternal::SetContents(WriteBatch* b, const Slice& contents) {
|
|
assert(contents.size() >= kHeader);
|
|
b->rep_.assign(contents.data(), contents.size());
|
|
}
|
|
|
|
void WriteBatchInternal::Append(WriteBatch* dst, const WriteBatch* src) {
|
|
SetCount(dst, Count(dst) + Count(src));
|
|
assert(src->rep_.size() >= kHeader);
|
|
dst->rep_.append(src->rep_.data() + kHeader, src->rep_.size() - kHeader);
|
|
}
|
|
|
|
} // namespace leveldb
|