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115 lines
3.0 KiB
115 lines
3.0 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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#include "db/true_iter.h"
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#include "db/db_impl.h"
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#include "db/dbformat.h"
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#include "db/filename.h"
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#include <fstream>
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#include <iostream>
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#include <queue>
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#include <thread>
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#include "leveldb/env.h"
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#include "leveldb/iterator.h"
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#include "port/port.h"
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#include "util/logging.h"
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#include "util/mutexlock.h"
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#include "util/random.h"
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namespace leveldb {
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namespace {
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// DBTrueIter simply wrap the DbIter and will parse the true value (maybe from
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// valuelog) for user.
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// if the crc check fail, DBTrueIter will skip the bad record
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// and show it to user by status().
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// bad status will remain showed by status(), like other iterator.
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class DBTrueIter : public Iterator {
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public:
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DBTrueIter(DBImpl* db, Iterator* iter, bool check_crc)
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: db_(db), iter_(iter), check_crc_(check_crc) {}
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DBTrueIter(const DBTrueIter&) = delete;
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DBTrueIter& operator=(const DBTrueIter&) = delete;
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~DBTrueIter() override { delete iter_; }
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bool Valid() const override { return iter_->Valid(); }
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Slice key() const override { return iter_->key(); }
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Slice value() const override {
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return Slice(buf_for_value.data(), buf_for_value.size());
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}
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Status status() const override {
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if (status_.ok())
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return iter_->status();
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else
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return status_;
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}
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void Next() override;
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void Prev() override;
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void Seek(const Slice& target) override;
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void SeekToFirst() override;
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void SeekToLast() override;
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private:
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Status GetAndParseTrueValue(Slice tmp_value) {
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Status status = db_->parseTrueValue(&tmp_value, &buf_for_value, check_crc_);
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if (!status.ok()) status_ = status;
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return status;
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}
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DBImpl* db_;
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Iterator* const iter_;
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std::string buf_for_value;
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Status status_ = Status::OK();
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bool check_crc_;
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};
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void DBTrueIter::Next() {
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iter_->Next();
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while (iter_->Valid()) {
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Status res = GetAndParseTrueValue(iter_->value());
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if (res.ok()) break;
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iter_->Next();
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}
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}
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void DBTrueIter::Prev() {
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iter_->Prev();
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while (iter_->Valid()) {
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Status res = GetAndParseTrueValue(iter_->value());
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if (res.ok()) break;
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iter_->Prev();
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}
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}
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void DBTrueIter::Seek(const Slice& target) {
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iter_->Seek(target);
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if (iter_->Valid()) {
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Status res = GetAndParseTrueValue(iter_->value());
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if (!res.ok()) Next(); // lowerbound
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}
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}
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void DBTrueIter::SeekToFirst() {
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iter_->SeekToFirst();
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if (iter_->Valid()) {
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Status res = GetAndParseTrueValue(iter_->value());
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if (!res.ok()) Next();
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}
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}
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void DBTrueIter::SeekToLast() {
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iter_->SeekToLast();
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if (iter_->Valid()) {
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Status res = GetAndParseTrueValue(iter_->value());
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if (!res.ok()) Prev();
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}
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}
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} // anonymous namespace
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Iterator* NewTrueIterator(DBImpl* db, Iterator* db_iter, bool check_crc) {
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return new DBTrueIter(db, db_iter, check_crc);
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}
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} // namespace leveldb
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