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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_TRANSACTION_H_
#define CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_TRANSACTION_H_
#include <map>
#include <memory>
#include <set>
#include <string>
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/strings/string_piece.h"
#include "content/browser/indexed_db/leveldb/leveldb_comparator.h"
#include "content/browser/indexed_db/leveldb/leveldb_database.h"
#include "content/browser/indexed_db/leveldb/leveldb_iterator.h"
namespace content {
class LevelDBWriteBatch;
class CONTENT_EXPORT LevelDBTransaction
: public base::RefCounted<LevelDBTransaction> {
public:
void Put(const base::StringPiece& key, std::string* value);
void Remove(const base::StringPiece& key);
virtual leveldb::Status Get(const base::StringPiece& key,
std::string* value,
bool* found);
virtual leveldb::Status Commit();
void Rollback();
std::unique_ptr<LevelDBIterator> CreateIterator();
protected:
virtual ~LevelDBTransaction();
explicit LevelDBTransaction(LevelDBDatabase* db);
friend class IndexedDBClassFactory;
private:
friend class base::RefCounted<LevelDBTransaction>;
FRIEND_TEST_ALL_PREFIXES(LevelDBDatabaseTest, Transaction);
FRIEND_TEST_ALL_PREFIXES(LevelDBDatabaseTest, TransactionCommitTest);
FRIEND_TEST_ALL_PREFIXES(LevelDBDatabaseTest, TransactionIterator);
struct Record {
Record();
~Record();
std::string key;
std::string value;
bool deleted;
};
class Comparator {
public:
explicit Comparator(const LevelDBComparator* comparator)
: comparator_(comparator) {}
bool operator()(const base::StringPiece& a,
const base::StringPiece& b) const {
return comparator_->Compare(a, b) < 0;
}
private:
const LevelDBComparator* comparator_;
};
typedef std::map<base::StringPiece, Record*, Comparator> DataType;
class DataIterator : public LevelDBIterator {
public:
static std::unique_ptr<DataIterator> Create(
LevelDBTransaction* transaction);
~DataIterator() override;
bool IsValid() const override;
leveldb::Status SeekToLast() override;
leveldb::Status Seek(const base::StringPiece& slice) override;
leveldb::Status Next() override;
leveldb::Status Prev() override;
base::StringPiece Key() const override;
base::StringPiece Value() const override;
bool IsDeleted() const;
private:
explicit DataIterator(LevelDBTransaction* transaction);
DataType* data_;
DataType::iterator iterator_;
DISALLOW_COPY_AND_ASSIGN(DataIterator);
};
class TransactionIterator : public LevelDBIterator {
public:
~TransactionIterator() override;
static std::unique_ptr<TransactionIterator> Create(
scoped_refptr<LevelDBTransaction> transaction);
bool IsValid() const override;
leveldb::Status SeekToLast() override;
leveldb::Status Seek(const base::StringPiece& target) override;
leveldb::Status Next() override;
leveldb::Status Prev() override;
base::StringPiece Key() const override;
base::StringPiece Value() const override;
void DataChanged();
private:
enum Direction { FORWARD, REVERSE };
explicit TransactionIterator(scoped_refptr<LevelDBTransaction> transaction);
void HandleConflictsAndDeletes();
void SetCurrentIteratorToSmallestKey();
void SetCurrentIteratorToLargestKey();
void RefreshDataIterator() const;
bool DataIteratorIsLower() const;
bool DataIteratorIsHigher() const;
scoped_refptr<LevelDBTransaction> transaction_;
const LevelDBComparator* comparator_;
mutable std::unique_ptr<DataIterator> data_iterator_;
std::unique_ptr<LevelDBIterator> db_iterator_;
LevelDBIterator* current_;
Direction direction_;
mutable bool data_changed_;
DISALLOW_COPY_AND_ASSIGN(TransactionIterator);
};
void Set(const base::StringPiece& key, std::string* value, bool deleted);
void Clear();
void RegisterIterator(TransactionIterator* iterator);
void UnregisterIterator(TransactionIterator* iterator);
void NotifyIterators();
LevelDBDatabase* db_;
const LevelDBSnapshot snapshot_;
const LevelDBComparator* comparator_;
Comparator data_comparator_;
DataType data_;
bool finished_;
std::set<TransactionIterator*> iterators_;
DISALLOW_COPY_AND_ASSIGN(LevelDBTransaction);
};
// Reads go straight to the database, ignoring any writes cached in
// write_batch_, and writes are write-through, without consolidation.
class LevelDBDirectTransaction {
public:
static std::unique_ptr<LevelDBDirectTransaction> Create(LevelDBDatabase* db);
~LevelDBDirectTransaction();
void Put(const base::StringPiece& key, const std::string* value);
leveldb::Status Get(const base::StringPiece& key,
std::string* value,
bool* found);
void Remove(const base::StringPiece& key);
leveldb::Status Commit();
private:
explicit LevelDBDirectTransaction(LevelDBDatabase* db);
LevelDBDatabase* db_;
std::unique_ptr<LevelDBWriteBatch> write_batch_;
bool finished_;
DISALLOW_COPY_AND_ASSIGN(LevelDBDirectTransaction);
};
} // namespace content
#endif // CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_TRANSACTION_H_
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