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164 linhas
4.4 KiB
164 linhas
4.4 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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//
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// WriteBatch::rep_ :=
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// sequence: fixed64
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// count: fixed32
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// data: record[count]
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// record :=
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// kTypeValue varstring varstring |
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// kTypeLargeValueRef varstring varstring |
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// kTypeDeletion varstring
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// varstring :=
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// len: varint32
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// data: uint8[len]
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#include "leveldb/write_batch.h"
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#include "leveldb/db.h"
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#include "db/dbformat.h"
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#include "db/memtable.h"
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#include "db/write_batch_internal.h"
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#include "util/coding.h"
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namespace leveldb {
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WriteBatch::WriteBatch() {
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Clear();
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}
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WriteBatch::~WriteBatch() { }
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void WriteBatch::Clear() {
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rep_.clear();
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rep_.resize(12);
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}
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int WriteBatchInternal::Count(const WriteBatch* b) {
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return DecodeFixed32(b->rep_.data() + 8);
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}
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void WriteBatchInternal::SetCount(WriteBatch* b, int n) {
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EncodeFixed32(&b->rep_[8], n);
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}
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SequenceNumber WriteBatchInternal::Sequence(const WriteBatch* b) {
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return SequenceNumber(DecodeFixed64(b->rep_.data()));
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}
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void WriteBatchInternal::SetSequence(WriteBatch* b, SequenceNumber seq) {
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EncodeFixed64(&b->rep_[0], seq);
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}
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void WriteBatch::Put(const Slice& key, const Slice& value) {
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WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
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rep_.push_back(static_cast<char>(kTypeValue));
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PutLengthPrefixedSlice(&rep_, key);
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PutLengthPrefixedSlice(&rep_, value);
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}
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void WriteBatchInternal::PutLargeValueRef(WriteBatch* b,
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const Slice& key,
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const LargeValueRef& large_ref) {
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WriteBatchInternal::SetCount(b, WriteBatchInternal::Count(b) + 1);
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b->rep_.push_back(static_cast<char>(kTypeLargeValueRef));
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PutLengthPrefixedSlice(&b->rep_, key);
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PutLengthPrefixedSlice(&b->rep_,
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Slice(large_ref.data, sizeof(large_ref.data)));
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}
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void WriteBatch::Delete(const Slice& key) {
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WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
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rep_.push_back(static_cast<char>(kTypeDeletion));
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PutLengthPrefixedSlice(&rep_, key);
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}
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Status WriteBatchInternal::InsertInto(const WriteBatch* b,
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MemTable* memtable) {
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const int count = WriteBatchInternal::Count(b);
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int found = 0;
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Iterator it(*b);
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for (; !it.Done(); it.Next()) {
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switch (it.op()) {
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case kTypeDeletion:
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memtable->Add(it.sequence_number(), kTypeDeletion, it.key(), Slice());
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break;
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case kTypeValue:
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memtable->Add(it.sequence_number(), kTypeValue, it.key(), it.value());
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break;
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case kTypeLargeValueRef:
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memtable->Add(it.sequence_number(), kTypeLargeValueRef,
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it.key(), it.value());
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break;
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}
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found++;
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}
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if (!it.status().ok()) {
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return it.status();
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} else if (found != count) {
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return Status::Corruption("wrong count in WriteBatch");
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}
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return Status::OK();
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}
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void WriteBatchInternal::SetContents(WriteBatch* b, const Slice& contents) {
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assert(contents.size() >= 12);
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b->rep_.assign(contents.data(), contents.size());
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}
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WriteBatchInternal::Iterator::Iterator(const WriteBatch& batch)
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: input_(WriteBatchInternal::Contents(&batch)),
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done_(false) {
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if (input_.size() < 12) {
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done_ = true;
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} else {
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seq_ = WriteBatchInternal::Sequence(&batch),
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input_.remove_prefix(12);
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GetNextEntry();
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}
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}
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void WriteBatchInternal::Iterator::Next() {
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assert(!done_);
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seq_++;
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GetNextEntry();
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}
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void WriteBatchInternal::Iterator::GetNextEntry() {
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if (input_.empty()) {
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done_ = true;
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return;
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}
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char tag = input_[0];
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input_.remove_prefix(1);
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switch (tag) {
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case kTypeValue:
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case kTypeLargeValueRef:
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if (GetLengthPrefixedSlice(&input_, &key_) &&
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GetLengthPrefixedSlice(&input_, &value_)) {
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op_ = static_cast<ValueType>(tag);
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} else {
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status_ = Status::Corruption("bad WriteBatch Put");
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done_ = true;
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input_.clear();
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}
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break;
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case kTypeDeletion:
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if (GetLengthPrefixedSlice(&input_, &key_)) {
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op_ = kTypeDeletion;
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} else {
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status_ = Status::Corruption("bad WriteBatch Delete");
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done_ = true;
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input_.clear();
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}
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break;
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default:
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status_ = Status::Corruption("unknown WriteBatch tag");
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done_ = true;
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input_.clear();
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break;
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}
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}
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}
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