item_p.h

/*
    Copyright (c) 2008 Tobias Koenig <tokoe@kde.org>

    This library is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    This library is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
    License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to the
    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA.
*/

#ifndef AKONADI_ITEM_P_H
#define AKONADI_ITEM_P_H

#include <QtCore/QDateTime>
#include <QtCore/QMap>
#include <QtCore/QVarLengthArray>

#include "entity_p.h"
#include "itempayloadinternals_p.h"

#include <boost/bind.hpp>

#include <memory>
#include <algorithm>
#include <cassert>
#include <vector>

namespace Akonadi {

namespace _detail {

    template <typename T>
    class clone_ptr {
        T * t;
    public:
        clone_ptr() : t( 0 ) {}
        explicit clone_ptr( T * t ) : t( t ) {}
        clone_ptr( const clone_ptr & other ) : t ( other.t ? other.t->clone() : 0 ) {}
        ~clone_ptr() { delete t; }
        clone_ptr & operator=( const clone_ptr & other ) {
            if ( this != &other ) {
                clone_ptr copy( other );
                swap( copy );
            }
            return *this;
        }
        void swap( clone_ptr & other ) {
            using std::swap;
            swap( t, other.t );
        }
        T * operator->() const { return get(); }
        T & operator*() const { assert( get() != 0 ); return *get(); }
        T * get() const { return t; }
        T * release() { T * const r = t; t = 0; return r; }
        void reset( T * other=0 ) { delete t; t = other; }

    private:
        struct _save_bool { void f() {}; };
        typedef void (_save_bool::*save_bool)();
    public:
        operator save_bool () const { return get() ? &_save_bool::f : 0 ; }
    };

    template <typename T>
    inline void swap( clone_ptr<T> & lhs, clone_ptr<T> & rhs ) {
        lhs.swap( rhs );
    }

    template <typename T, size_t N>
    class VarLengthArray {
        QVarLengthArray<T,N> impl; // ###should be replaced by self-written container that doesn't waste so much space
    public:
        typedef T value_type;
        typedef T* iterator;
        typedef const T* const_iterator;
        typedef T* pointer;
        typedef const T* const_pointer;
        typedef T & reference;
        typedef const T & const_reference;

        explicit VarLengthArray( int size=0 ) : impl( size ) {}
        // compiler-generated dtor, copy ctor, copy assignment are ok
        // swap() makes little sense

        void push_back( const T & t ) { impl.append( t ); }
        int capacity() const          { return impl.capacity(); }
        void clear()                  { impl.clear(); }
        size_t size() const           { return impl.count(); }
        bool empty() const            { return impl.isEmpty(); }
        void pop_back()               { return impl.removeLast(); }
        void reserve( size_t n )      { impl.reserve( n ); }
        void resize( size_t n )       { impl.resize( n ); }

        iterator begin()              { return impl.data(); }
        iterator end()                { return impl.data() + impl.size(); }
        const_iterator begin()  const { return impl.data(); }
        const_iterator end()    const { return impl.data() + impl.size(); }
        const_iterator cbegin() const { return begin(); }
        const_iterator cend()   const { return end(); }

        reference       front()       { return *impl.data(); }
        reference       back()        { return *(impl.data()+impl.size()); }
        const_reference front() const { return *impl.data(); }
        const_reference back()  const { return *(impl.data()+impl.size()); }

        reference       operator[]( size_t n )       { return impl[n]; }
        const_reference operator[]( size_t n ) const { return impl[n]; }
    };

    struct TypedPayload {
        clone_ptr<PayloadBase> payload;
        int sharedPointerId;
        int metaTypeId;
    };

    struct BySharedPointerAndMetaTypeID : std::unary_function<TypedPayload,bool> {
        const int spid;
        const int mtid;
        BySharedPointerAndMetaTypeID( int spid, int mtid ) : spid( spid ), mtid( mtid ) {}
        bool operator()( const TypedPayload & tp ) const {
            return ( mtid == -1 || mtid == tp.metaTypeId )
                && ( spid == -1 || spid == tp.sharedPointerId ) ;
        }
    };

}

} // namespace Akonadi

namespace std {
    template <>
    inline void swap<Akonadi::_detail::TypedPayload>( Akonadi::_detail::TypedPayload & lhs, Akonadi::_detail::TypedPayload & rhs ) {
        lhs.payload.swap( rhs.payload );
        swap( lhs.sharedPointerId, rhs.sharedPointerId );
        swap( lhs.metaTypeId, rhs.metaTypeId );
    }
}

namespace Akonadi {
//typedef _detail::VarLengthArray<_detail::TypedPayload,2> PayloadContainer;
typedef std::vector<_detail::TypedPayload> PayloadContainer;
}

// disable Q_FOREACH on PayloadContainer (b/c it likes to take copies and clone_ptr doesn't like that)
template <>
class QForeachContainer<Akonadi::PayloadContainer> {};

namespace Akonadi {

class ItemPrivate : public EntityPrivate
{
  public:
    explicit ItemPrivate( Item::Id id = -1 )
      : EntityPrivate( id ),
        mLegacyPayload(),
        mPayloads(),
        mConversionInProgress( false ),
        mRevision( -1 ),
        mCollectionId( -1 ),
        mSize( 0 ),
        mModificationTime(),
        mFlagsOverwritten( false ),
        mSizeChanged( false ),
        mClearPayload( false )
    {
    }

#if 0
    ItemPrivate( const ItemPrivate &other )
        : EntityPrivate( other )
    {
      mFlags = other.mFlags;
      mRevision = other.mRevision;
      mSize = other.mSize;
      mModificationTime = other.mModificationTime;
      mMimeType = other.mMimeType;
      mLegacyPayload = other.mLegacyPayload;
      mPayloads = other.mPayloads;
      mConversionInProgress = false;
      mAddedFlags = other.mAddedFlags;
      mDeletedFlags = other.mDeletedFlags;
      mFlagsOverwritten = other.mFlagsOverwritten;
      mSizeChanged = other.mSizeChanged;
      mCollectionId = other.mCollectionId;
      mClearPayload = other.mClearPayload;
    }
#endif

    ~ItemPrivate()
    {
    }

    void resetChangeLog()
    {
      mFlagsOverwritten = false;
      mAddedFlags.clear();
      mDeletedFlags.clear();
      mSizeChanged = false;
    }

    EntityPrivate *clone() const
    {
      return new ItemPrivate( *this );
    }

    bool hasMetaTypeId( int mtid ) const {
        return std::find_if( mPayloads.begin(), mPayloads.end(),
                             _detail::BySharedPointerAndMetaTypeID( -1, mtid ) )
            != mPayloads.end();
    }

    PayloadBase * payloadBaseImpl( int spid, int mtid ) const {
        const PayloadContainer::const_iterator it
            = std::find_if( mPayloads.begin(), mPayloads.end(),
                            _detail::BySharedPointerAndMetaTypeID( spid, mtid ) );
        return it == mPayloads.end() ? 0 : it->payload.get() ;
    }

    bool movePayloadFrom( ItemPrivate * other, int mtid ) const /*sic!*/ {
      assert( other );
      const size_t oldSize = mPayloads.size();
      PayloadContainer & oPayloads = other->mPayloads;
      const _detail::BySharedPointerAndMetaTypeID matcher( -1, mtid );
      const size_t numMatching
        = std::count_if( oPayloads.begin(), oPayloads.end(), matcher );
      mPayloads.resize( oldSize + numMatching );
      using namespace std; // for swap()
      for ( PayloadContainer::iterator
              dst = mPayloads.begin() + oldSize,
              src = oPayloads.begin(), end = oPayloads.end() ; src != end ; ++src )
        if ( matcher( *src ) ) {
          swap( *dst, *src );
          ++dst;
        }
      return numMatching > 0 ;
    }

#if 0
    std::auto_ptr<PayloadBase> takePayloadBaseImpl( int spid, int mtid ) {
        PayloadContainer::iterator it
            = std::find_if( mPayloads.begin(), mPayloads.end(),
                            _detail::BySharedPointerAndMetaTypeID( spid, mtid ) );
        if ( it == mPayloads.end() )
            return std::auto_ptr<PayloadBase>();
        std::rotate( it, it + 1, mPayloads.end() );
        std::auto_ptr<PayloadBase> result( it->payload.release() );
        mPayloads.pop_back();
        return result;
    }
#endif

    void setPayloadBaseImpl( int spid, int mtid, std::auto_ptr<PayloadBase> p, bool add ) const /*sic!*/ {

        if ( !add )
            mLegacyPayload.reset();

        if ( !p.get() ) {
            if ( !add )
                mPayloads.clear();
            return;
        }

        // if !add, delete all payload variants
        // (they're conversions of each other)
        mPayloads.resize( add ? mPayloads.size() + 1 : 1 );
        _detail::TypedPayload & tp = mPayloads.back();
        tp.payload.reset( p.release() );
        tp.sharedPointerId = spid;
        tp.metaTypeId = mtid;
    }

    void setLegacyPayloadBaseImpl( std::auto_ptr<PayloadBase> p );
    void tryEnsureLegacyPayload() const;

    mutable _detail::clone_ptr<PayloadBase> mLegacyPayload;
    mutable PayloadContainer mPayloads;
    mutable bool mConversionInProgress;
    int mRevision;
    Item::Flags mFlags;
    Entity::Id mCollectionId;
    qint64 mSize;
    QDateTime mModificationTime;
    QString mMimeType;
    QString mGid;
    Item::Flags mAddedFlags;
    Item::Flags mDeletedFlags;
    QSet<QByteArray> mCachedPayloadParts;
    bool mFlagsOverwritten : 1;
    bool mSizeChanged : 1;
    bool mClearPayload : 1;
};

}

#endif