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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 <set>
#include <string>
#include <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_piece.h"
#include "content/browser/indexed_db/leveldb/avltree.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:
explicit LevelDBTransaction(LevelDBDatabase* db);
void Put(const base::StringPiece& key, std::string* value);
void Remove(const base::StringPiece& key);
bool Get(const base::StringPiece& key, std::string* value, bool* found);
bool Commit();
void Rollback();
scoped_ptr<LevelDBIterator> CreateIterator();
private:
virtual ~LevelDBTransaction();
friend class base::RefCounted<LevelDBTransaction>;
struct AVLTreeNode {
AVLTreeNode();
~AVLTreeNode();
std::string key;
std::string value;
bool deleted;
AVLTreeNode* less;
AVLTreeNode* greater;
int balance_factor;
DISALLOW_COPY_AND_ASSIGN(AVLTreeNode);
};
struct AVLTreeAbstractor {
typedef AVLTreeNode* handle;
typedef size_t size;
typedef base::StringPiece key;
handle GetLess(handle h) { return h->less; }
void SetLess(handle h, handle less) { h->less = less; }
handle GetGreater(handle h) { return h->greater; }
void SetGreater(handle h, handle greater) { h->greater = greater; }
int GetBalanceFactor(handle h) { return h->balance_factor; }
void SetBalanceFactor(handle h, int bf) { h->balance_factor = bf; }
int CompareKeyKey(const key& ka, const key& kb) {
return comparator_->Compare(ka, kb);
}
int CompareKeyNode(const key& k, handle h) {
return CompareKeyKey(k, h->key);
}
int CompareNodeNode(handle ha, handle hb) {
return CompareKeyKey(ha->key, hb->key);
}
static handle Null() { return 0; }
const LevelDBComparator* comparator_;
};
typedef AVLTree<AVLTreeAbstractor> TreeType;
class TreeIterator : public LevelDBIterator {
public:
static scoped_ptr<TreeIterator> Create(LevelDBTransaction* transaction);
virtual ~TreeIterator();
virtual bool IsValid() const OVERRIDE;
virtual void SeekToLast() OVERRIDE;
virtual void Seek(const base::StringPiece& slice) OVERRIDE;
virtual void Next() OVERRIDE;
virtual void Prev() OVERRIDE;
virtual base::StringPiece Key() const OVERRIDE;
virtual base::StringPiece Value() const OVERRIDE;
bool IsDeleted() const;
void Reset();
private:
explicit TreeIterator(LevelDBTransaction* transaction);
mutable TreeType::Iterator iterator_; // Dereferencing this is non-const.
TreeType* tree_;
LevelDBTransaction* transaction_;
std::string key_;
};
class TransactionIterator : public LevelDBIterator {
public:
virtual ~TransactionIterator();
static scoped_ptr<TransactionIterator> Create(
scoped_refptr<LevelDBTransaction> transaction);
virtual bool IsValid() const OVERRIDE;
virtual void SeekToLast() OVERRIDE;
virtual void Seek(const base::StringPiece& target) OVERRIDE;
virtual void Next() OVERRIDE;
virtual void Prev() OVERRIDE;
virtual base::StringPiece Key() const OVERRIDE;
virtual base::StringPiece Value() const OVERRIDE;
void TreeChanged();
private:
explicit TransactionIterator(scoped_refptr<LevelDBTransaction> transaction);
void HandleConflictsAndDeletes();
void SetCurrentIteratorToSmallestKey();
void SetCurrentIteratorToLargestKey();
void RefreshTreeIterator() const;
bool TreeIteratorIsLower() const;
bool TreeIteratorIsHigher() const;
scoped_refptr<LevelDBTransaction> transaction_;
const LevelDBComparator* comparator_;
mutable scoped_ptr<TreeIterator> tree_iterator_;
scoped_ptr<LevelDBIterator> db_iterator_;
LevelDBIterator* current_;
enum Direction {
FORWARD,
REVERSE
};
Direction direction_;
mutable bool tree_changed_;
};
void Set(const base::StringPiece& key, std::string* value, bool deleted);
void ClearTree();
void RegisterIterator(TransactionIterator* iterator);
void UnregisterIterator(TransactionIterator* iterator);
void NotifyIteratorsOfTreeChange();
LevelDBDatabase* db_;
const LevelDBSnapshot snapshot_;
const LevelDBComparator* comparator_;
TreeType tree_;
bool finished_;
std::set<TransactionIterator*> iterators_;
};
class LevelDBWriteOnlyTransaction {
public:
static scoped_ptr<LevelDBWriteOnlyTransaction> Create(LevelDBDatabase* db);
~LevelDBWriteOnlyTransaction();
void Remove(const base::StringPiece& key);
bool Commit();
private:
explicit LevelDBWriteOnlyTransaction(LevelDBDatabase* db);
LevelDBDatabase* db_;
scoped_ptr<LevelDBWriteBatch> write_batch_;
bool finished_;
};
} // namespace content
#endif // CONTENT_BROWSER_INDEXED_DB_LEVELDB_LEVELDB_TRANSACTION_H_
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