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// 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 |
// kTypeLargeValueRef varstring varstring |
// kTypeDeletion varstring
// varstring :=
// len: varint32
// data: uint8[len]
#include "leveldb/write_batch.h"
#include "leveldb/db.h"
#include "db/dbformat.h"
#include "db/memtable.h"
#include "db/write_batch_internal.h"
#include "util/coding.h"
namespace leveldb {
WriteBatch::WriteBatch() {
Clear();
}
WriteBatch::~WriteBatch() { }
void WriteBatch::Clear() {
rep_.clear();
rep_.resize(12);
}
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 WriteBatchInternal::PutLargeValueRef(WriteBatch* b,
const Slice& key,
const LargeValueRef& large_ref) {
WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
b->rep_.push_back(static_cast<char>(kTypeLargeValueRef));
PutLengthPrefixedSlice(&b->rep_, key);
PutLengthPrefixedSlice(&b->rep_,
Slice(large_ref.data, sizeof(large_ref.data)));
}
void WriteBatch::Delete(const Slice& key) {
WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
rep_.push_back(static_cast<char>(kTypeDeletion));
PutLengthPrefixedSlice(&rep_, key);
}
Status WriteBatchInternal::InsertInto(const WriteBatch* b,
MemTable* memtable) {
const int count = WriteBatchInternal::Count(b);
int found = 0;
Iterator it(*b);
for (; !it.Done(); it.Next()) {
switch (it.op()) {
case kTypeDeletion:
memtable->Add(it.sequence_number(), kTypeDeletion, it.key(), Slice());
break;
case kTypeValue:
memtable->Add(it.sequence_number(), kTypeValue, it.key(), it.value());
break;
case kTypeLargeValueRef:
memtable->Add(it.sequence_number(), kTypeLargeValueRef,
it.key(), it.value());
break;
}
found++;
}
if (!it.status().ok()) {
return it.status();
} else if (found != count) {
return Status::Corruption("wrong count in WriteBatch");
}
return Status::OK();
}
void WriteBatchInternal::SetContents(WriteBatch* b, const Slice& contents) {
assert(contents.size() >= 12);
b->rep_.assign(contents.data(), contents.size());
}
WriteBatchInternal::Iterator::Iterator(const WriteBatch& batch)
: input_(WriteBatchInternal::Contents(&batch)),
done_(false) {
if (input_.size() < 12) {
done_ = true;
} else {
seq_ = WriteBatchInternal::Sequence(&batch),
input_.remove_prefix(12);
GetNextEntry();
}
}
void WriteBatchInternal::Iterator::Next() {
assert(!done_);
seq_++;
GetNextEntry();
}
void WriteBatchInternal::Iterator::GetNextEntry() {
if (input_.empty()) {
done_ = true;
return;
}
char tag = input_[0];
input_.remove_prefix(1);
switch (tag) {
case kTypeValue:
case kTypeLargeValueRef:
if (GetLengthPrefixedSlice(&input_, &key_) &&
GetLengthPrefixedSlice(&input_, &value_)) {
op_ = static_cast<ValueType>(tag);
} else {
status_ = Status::Corruption("bad WriteBatch Put");
done_ = true;
input_.clear();
}
break;
case kTypeDeletion:
if (GetLengthPrefixedSlice(&input_, &key_)) {
op_ = kTypeDeletion;
} else {
status_ = Status::Corruption("bad WriteBatch Delete");
done_ = true;
input_.clear();
}
break;
default:
status_ = Status::Corruption("unknown WriteBatch tag");
done_ = true;
input_.clear();
break;
}
}
}
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