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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 <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.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"
#include "content/browser/indexed_db/leveldb/leveldb_slice.h"
namespace content {
class LevelDBWriteBatch;
class CONTENT_EXPORT LevelDBTransaction
: public base::RefCounted<LevelDBTransaction> {
public:
static scoped_refptr<LevelDBTransaction> Create(LevelDBDatabase* db);
void Put(const LevelDBSlice& key, const std::vector<char>& value);
void Remove(const LevelDBSlice& key);
bool Get(const LevelDBSlice& key, std::vector<char>& value, bool& found);
bool Commit();
void Rollback();
scoped_ptr<LevelDBIterator> CreateIterator();
private:
LevelDBTransaction(LevelDBDatabase* db);
virtual ~LevelDBTransaction();
friend class base::RefCounted<LevelDBTransaction>;
struct AVLTreeNode {
AVLTreeNode();
~AVLTreeNode();
std::vector<char> key;
std::vector<char> 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 LevelDBSlice key;
handle get_less(handle h) { return h->less; }
void set_less(handle h, handle less) { h->less = less; }
handle get_greater(handle h) { return h->greater; }
void set_greater(handle h, handle greater) { h->greater = greater; }
int get_balance_factor(handle h) { return h->balance_factor; }
void set_balance_factor(handle h, int bf) { h->balance_factor = bf; }
int compare_key_key(const key& ka, const key& kb) {
return comparator_->Compare(ka, kb);
}
int compare_key_node(const key& k, handle h) {
return compare_key_key(k, key(h->key));
}
int compare_node_node(handle ha, handle hb) {
return compare_key_key(key(ha->key), 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 LevelDBSlice& slice) OVERRIDE;
virtual void Next() OVERRIDE;
virtual void Prev() OVERRIDE;
virtual LevelDBSlice Key() const OVERRIDE;
virtual LevelDBSlice Value() const OVERRIDE;
bool IsDeleted() const;
void Reset();
private:
TreeIterator(LevelDBTransaction* transaction);
mutable TreeType::Iterator iterator_; // Dereferencing this is non-const.
TreeType* tree_;
LevelDBTransaction* transaction_;
std::vector<char> 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 LevelDBSlice& target) OVERRIDE;
virtual void Next() OVERRIDE;
virtual void Prev() OVERRIDE;
virtual LevelDBSlice Key() const OVERRIDE;
virtual LevelDBSlice Value() const OVERRIDE;
void TreeChanged();
private:
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 LevelDBSlice& key,
const std::vector<char>& 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 LevelDBSlice& key);
bool Commit();
private:
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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