liboh/include/sirikata/oh/Storage.hpp

Go to the documentation of this file.

/*  Sirikata
 *  Storage.hpp
 *
 *  Copyright (c) 2010, Stanford University
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * 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.
 *  * Neither the name of Sirikata nor the names of its contributors may
 *    be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __SIRIKATA_OH_STORAGE_HPP__
#define __SIRIKATA_OH_STORAGE_HPP__

#include <sirikata/core/util/Platform.hpp>
#include <sirikata/oh/Platform.hpp>
#include <sirikata/oh/HostedObject.hpp>
#include <sirikata/core/util/Factory.hpp>

namespace Sirikata {
namespace OH {

class SIRIKATA_OH_EXPORT Storage : public Service {
public:
    // A storage implementation contains a set of 'buckets' which
    // provide isolated storage for each object.
    typedef UUID Bucket;

    // Keys are arbitrary-length strings -- the namespace is flat, but
    // it is easy to add human readable hierarchy using a separator
    // (e.g. '.') and a bit of escaping.
    typedef String Key;

    enum Result {
        // Successful. Any data read back should be available in
        // corresponding callback arguments.
        SUCCESS = 0,

        // Failed to lock database or gain a lease. This rarely
        // indicates permanent failure. Rather, it indicates that
        // access to the database was blocked, probably temporarily as
        // an existing lease is blocking it (possibly to be freed up
        // when it automatically expires). Retrying is a reasonable
        // course of action here.
        LOCK_ERROR = 1,

        // There was an error applying the transaction. This could be due to a
        // missing key (for reads), a compare error, or and error writing or
        // erasing a key. The particular error is not specified because
        // operations can be reordered by the implementation for efficiency.
        TRANSACTION_ERROR = 2
    };

    typedef std::tr1::unordered_map<Key, String> ReadSet;
    typedef std::tr1::function<void(Result result, ReadSet* rs)> CommitCallback;
    typedef std::tr1::function<void(Result result, int32 count)> CountCallback;

    virtual ~Storage() {};

    virtual void start() {}
    virtual void stop() {}


    virtual void leaseBucket(const Bucket& bucket) = 0;
    virtual void releaseBucket(const Bucket& bucket) = 0;


    virtual void beginTransaction(const Bucket& bucket) = 0;

    virtual void commitTransaction(const Bucket& bucket, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    virtual bool erase(const Bucket& bucket, const Key& key, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    virtual bool write(const Bucket& bucket, const Key& key, const String& value, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    virtual bool read(const Bucket& bucket, const Key& key, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    virtual bool rangeRead(const Bucket& bucket, const Key& start, const Key& finish, const CommitCallback& cb = 0, const String& timestamp="current") = 0;


    virtual bool compare(const Bucket& bucket, const Key& key, const String& value, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    virtual bool rangeErase(const Bucket& bucket, const Key& start, const Key& finish, const CommitCallback& cb = 0, const String& timestamp="current") = 0;

    // TODO(ewencp) this interface seems broken -- because it uses a different
    // callback, it doesn't fit in with transactions. This currently *has* to be
    // handled separately from other actions...
    virtual bool count(const Bucket& bucket, const Key& start, const Key& finish, const CountCallback& cb = 0, const String& timestamp="current") = 0;
};


class SIRIKATA_OH_EXPORT StorageFactory
    : public AutoSingleton<StorageFactory>,
      public Factory2<Storage*, ObjectHostContext*, const String&>
{
public:
    static StorageFactory& getSingleton();
    static void destroy();
};

} //end namespace OH
} //end namespace Sirikata

#endif //__SIRIKATA_OH_STORAGE_HPP__