Source/modules/indexeddb/IDBLevelDBCoding.h

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef IDBLevelDBCoding_h
#define IDBLevelDBCoding_h

#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
#include "wtf/text/WTFString.h"

namespace WebCore {

class IDBKey;
class IDBKeyPath;
class LevelDBSlice;

namespace IDBLevelDBCoding {

const unsigned char MinimumIndexId = 30;

// As most of the IDBKeys and encoded values are short, we initialize some Vectors with a default inline buffer size
// to reduce the memory re-allocations when the Vectors are appended.
static const size_t DefaultInlineBufferSize = 32;

Vector<char> encodeByte(unsigned char);
const char* decodeByte(const char* p, const char* limit, unsigned char& foundChar);
Vector<char> maxIDBKey();
Vector<char> minIDBKey();
Vector<char> encodeBool(bool);
bool decodeBool(const char* begin, const char* end);
Vector<char> encodeInt(int64_t);
inline Vector<char> encodeIntSafely(int64_t nParam, int64_t max)
{
    ASSERT(nParam <= max);
    return encodeInt(nParam);
}
int64_t decodeInt(const char* begin, const char* end);
Vector<char> encodeVarInt(int64_t);
const char* decodeVarInt(const char* p, const char* limit, int64_t& foundInt);
Vector<char> encodeString(const String&);
String decodeString(const char* p, const char* end);
Vector<char> encodeStringWithLength(const String&);
const char* decodeStringWithLength(const char* p, const char* limit, String& foundString);
int compareEncodedStringsWithLength(const char*& p, const char* limitP, const char*& q, const char* limitQ, bool& ok);
Vector<char> encodeDouble(double);
const char* decodeDouble(const char* p, const char* limit, double*);
void encodeIDBKey(const IDBKey&, Vector<char, DefaultInlineBufferSize>& into);
Vector<char> encodeIDBKey(const IDBKey&);
const char* decodeIDBKey(const char* p, const char* limit, RefPtr<IDBKey>& foundKey);
const char* extractEncodedIDBKey(const char* start, const char* limit, Vector<char>* result);
int compareEncodedIDBKeys(const Vector<char>&, const Vector<char>&, bool& ok);
Vector<char> encodeIDBKeyPath(const IDBKeyPath&);
IDBKeyPath decodeIDBKeyPath(const char*, const char*);

int compare(const LevelDBSlice&, const LevelDBSlice&, bool indexKeys = false);

class KeyPrefix {
public:
    KeyPrefix();
    explicit KeyPrefix(int64_t databaseId);
    KeyPrefix(int64_t databaseId, int64_t objectStoreId);
    KeyPrefix(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    static KeyPrefix createWithSpecialIndex(int64_t databaseId, int64_t objectStoreId, int64_t indexId);

    static const char* decode(const char* start, const char* limit, KeyPrefix* result);
    Vector<char> encode() const;
    static Vector<char> encodeEmpty();
    int compare(const KeyPrefix& other) const;

    enum Type {
        GlobalMetaData,
        DatabaseMetaData,
        ObjectStoreData,
        ExistsEntry,
        IndexData,
        InvalidType
    };

    static const size_t kMaxDatabaseIdSizeBits = 3;
    static const size_t kMaxObjectStoreIdSizeBits = 3;
    static const size_t kMaxIndexIdSizeBits = 2;

    static const size_t kMaxDatabaseIdSizeBytes = 1ULL << kMaxDatabaseIdSizeBits; // 8
    static const size_t kMaxObjectStoreIdSizeBytes = 1ULL << kMaxObjectStoreIdSizeBits; // 8
    static const size_t kMaxIndexIdSizeBytes = 1ULL << kMaxIndexIdSizeBits; // 4

    static const size_t kMaxDatabaseIdBits = kMaxDatabaseIdSizeBytes * 8 - 1; // 63
    static const size_t kMaxObjectStoreIdBits = kMaxObjectStoreIdSizeBytes * 8 - 1; // 63
    static const size_t kMaxIndexIdBits = kMaxIndexIdSizeBytes * 8 - 1; // 31

    static const int64_t kMaxDatabaseId = (1ULL << kMaxDatabaseIdBits) - 1; // max signed int64_t
    static const int64_t kMaxObjectStoreId = (1ULL << kMaxObjectStoreIdBits) - 1; // max signed int64_t
    static const int64_t kMaxIndexId = (1ULL << kMaxIndexIdBits) - 1; // max signed int32_t

    static bool isValidDatabaseId(int64_t databaseId);
    static bool isValidObjectStoreId(int64_t indexId);
    static bool isValidIndexId(int64_t indexId);
    static bool validIds(int64_t databaseId, int64_t objectStoreId, int64_t indexId)
    {
        return isValidDatabaseId(databaseId) && isValidObjectStoreId(objectStoreId) && isValidIndexId(indexId);
    }
    static bool validIds(int64_t databaseId, int64_t objectStoreId)
    {
        return isValidDatabaseId(databaseId) && isValidObjectStoreId(objectStoreId);
    }

    Type type() const;

    int64_t m_databaseId;
    int64_t m_objectStoreId;
    int64_t m_indexId;

    static const int64_t InvalidId = -1;

private:
    static Vector<char> encodeInternal(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    // Special constructor for createWithSpecialIndex()
    KeyPrefix(Type, int64_t databaseId, int64_t objectStoreId, int64_t indexId);
};

class SchemaVersionKey {
public:
    static Vector<char> encode();
};

class MaxDatabaseIdKey {
public:
    static Vector<char> encode();
};

class DataVersionKey {
public:
    static Vector<char> encode();
};

class DatabaseFreeListKey {
public:
    DatabaseFreeListKey();
    static const char* decode(const char* start, const char* limit, DatabaseFreeListKey* result);
    static Vector<char> encode(int64_t databaseId);
    static Vector<char> encodeMaxKey();
    int64_t databaseId() const;
    int compare(const DatabaseFreeListKey& other) const;

private:
    int64_t m_databaseId;
};

class DatabaseNameKey {
public:
    static const char* decode(const char* start, const char* limit, DatabaseNameKey* result);
    static Vector<char> encode(const String& origin, const String& databaseName);
    static Vector<char> encodeMinKeyForOrigin(const String& origin);
    static Vector<char> encodeStopKeyForOrigin(const String& origin);
    String origin() const { return m_origin; }
    String databaseName() const { return m_databaseName; }
    int compare(const DatabaseNameKey& other);

private:
    String m_origin; // FIXME: Store encoded strings, or just pointers.
    String m_databaseName;
};

class DatabaseMetaDataKey {
public:
    enum MetaDataType {
        OriginName = 0,
        DatabaseName = 1,
        UserVersion = 2,
        MaxObjectStoreId = 3,
        UserIntVersion = 4,
        MaxSimpleMetaDataType = 5
    };

    static Vector<char> encode(int64_t databaseId, MetaDataType);
};

class ObjectStoreMetaDataKey {
public:
    enum MetaDataType {
        Name = 0,
        KeyPath = 1,
        AutoIncrement = 2,
        Evictable = 3,
        LastVersion = 4,
        MaxIndexId = 5,
        HasKeyPath = 6,
        KeyGeneratorCurrentNumber = 7
    };

    ObjectStoreMetaDataKey();
    static const char* decode(const char* start, const char* limit, ObjectStoreMetaDataKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, unsigned char metaDataType);
    static Vector<char> encodeMaxKey(int64_t databaseId);
    static Vector<char> encodeMaxKey(int64_t databaseId, int64_t objectStoreId);
    int64_t objectStoreId() const;
    unsigned char metaDataType() const;
    int compare(const ObjectStoreMetaDataKey& other);

private:
    int64_t m_objectStoreId;
    unsigned char m_metaDataType;
};

class IndexMetaDataKey {
public:
    enum MetaDataType {
        Name = 0,
        Unique = 1,
        KeyPath = 2,
        MultiEntry = 3
    };

    IndexMetaDataKey();
    static const char* decode(const char* start, const char* limit, IndexMetaDataKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, int64_t indexId, unsigned char metaDataType);
    static Vector<char> encodeMaxKey(int64_t databaseId, int64_t objectStoreId);
    static Vector<char> encodeMaxKey(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    int compare(const IndexMetaDataKey& other);
    int64_t indexId() const;
    unsigned char metaDataType() const { return m_metaDataType; }

private:
    int64_t m_objectStoreId;
    int64_t m_indexId;
    unsigned char m_metaDataType;
};

class ObjectStoreFreeListKey {
public:
    ObjectStoreFreeListKey();
    static const char* decode(const char* start, const char* limit, ObjectStoreFreeListKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId);
    static Vector<char> encodeMaxKey(int64_t databaseId);
    int64_t objectStoreId() const;
    int compare(const ObjectStoreFreeListKey& other);

private:
    int64_t m_objectStoreId;
};

class IndexFreeListKey {
public:
    IndexFreeListKey();
    static const char* decode(const char* start, const char* limit, IndexFreeListKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    static Vector<char> encodeMaxKey(int64_t databaseId, int64_t objectStoreId);
    int compare(const IndexFreeListKey& other);
    int64_t objectStoreId() const;
    int64_t indexId() const;

private:
    int64_t m_objectStoreId;
    int64_t m_indexId;
};

class ObjectStoreNamesKey {
public:
    // FIXME: We never use this to look up object store ids, because a mapping
    // is kept in the IDBDatabaseBackendImpl. Can the mapping become unreliable?
    // Can we remove this?
    static const char* decode(const char* start, const char* limit, ObjectStoreNamesKey* result);
    static Vector<char> encode(int64_t databaseId, const String& objectStoreName);
    int compare(const ObjectStoreNamesKey& other);
    String objectStoreName() const { return m_objectStoreName; }

private:
    String m_objectStoreName; // FIXME: Store the encoded string, or just pointers to it.
};

class IndexNamesKey {
public:
    IndexNamesKey();
    // FIXME: We never use this to look up index ids, because a mapping
    // is kept at a higher level.
    static const char* decode(const char* start, const char* limit, IndexNamesKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, const String& indexName);
    int compare(const IndexNamesKey& other);
    String indexName() const { return m_indexName; }

private:
    int64_t m_objectStoreId;
    String m_indexName;
};

class ObjectStoreDataKey {
public:
    static const char* decode(const char* start, const char* end, ObjectStoreDataKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, const Vector<char> encodedUserKey);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, const IDBKey& userKey);
    int compare(const ObjectStoreDataKey& other, bool& ok);
    PassRefPtr<IDBKey> userKey() const;
    static const int64_t SpecialIndexNumber;

private:
    Vector<char> m_encodedUserKey;
};

class ExistsEntryKey {
public:
    static const char* decode(const char* start, const char* end, ExistsEntryKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, const Vector<char>& encodedKey);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, const IDBKey& userKey);
    int compare(const ExistsEntryKey& other, bool& ok);
    PassRefPtr<IDBKey> userKey() const;

    static const int64_t SpecialIndexNumber;

private:
    Vector<char> m_encodedUserKey;
};

class IndexDataKey {
public:
    IndexDataKey();
    static const char* decode(const char* start, const char* limit, IndexDataKey* result);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, int64_t indexId, const Vector<char>& encodedUserKey, const Vector<char>& encodedPrimaryKey, int64_t sequenceNumber = 0);
    static Vector<char> encode(int64_t databaseId, int64_t objectStoreId, int64_t indexId, const IDBKey& userKey);
    static Vector<char> encodeMinKey(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    static Vector<char> encodeMaxKey(int64_t databaseId, int64_t objectStoreId, int64_t indexId);
    int compare(const IndexDataKey& other, bool ignoreDuplicates, bool& ok);
    int64_t databaseId() const;
    int64_t objectStoreId() const;
    int64_t indexId() const;
    PassRefPtr<IDBKey> userKey() const;
    PassRefPtr<IDBKey> primaryKey() const;

private:
    int64_t m_databaseId;
    int64_t m_objectStoreId;
    int64_t m_indexId;
    Vector<char> m_encodedUserKey;
    Vector<char> m_encodedPrimaryKey;
    int64_t m_sequenceNumber;
};

} // namespace IDBLevelDBCoding

} // namespace WebCore

#endif // IDBLevelDBCoding_h