/*

 * Copyright (c) 2003-2005 Nokia Corporation and/or its subsidiary(-ies).

 * All rights reserved.

 * This component and the accompanying materials are made available

 * under the terms of "Eclipse Public License v1.0"

 * which accompanies this distribution, and is available

 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

 *

 * Initial Contributors:

 * Nokia Corporation - initial contribution.

 *

 * Contributors:

 *

 * Description:     Variant data type for AIW generic parameters.

 *

 */

 #ifndef AIW_VARIANT_H

 #define AIW_VARIANT_H

 // INCLUDES

 #include <e32std.h>

 #include <s32strm.h>

 #include <f32file.h>

 #include "AiwVariantType.hrh"

 // FORWARD DECLARATIONS

 // CLASS DECLARATION

 /**

 * Variant data class to hold a value of a TAiwGenericParam instance.

 * The variant contains a data type and a value. This class is attached to

 * TAiwGenericParam instance which holds the semantic type of the value.

 *

 * @lib ServiceHandler.lib

 * @since Series 60 2.6

 * @see TAiwGenericParam

 */

 class TAiwVariant

     {

     public:  // Constructors

         /**

         * Default constructor. Initializes this variant to be empty.

         *

         * @post IsEmpty()

         */

         inline TAiwVariant();

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */

         inline TAiwVariant(TInt32 aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const TUid& aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const TTime& aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const TDesC& aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const HBufC* aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const TDesC8& aValue);

         /**

         * Constructor from a value.

         *

         * @param aValue The value to set for this variant object.

         */        

         inline TAiwVariant(const RFile& aValue);

         /**

         * Copy constructor. Does not take ownership of data.

         *

         * @param aSrc The source object.

         */

         IMPORT_C TAiwVariant(const TAiwVariant& aSrc);

         /**

         * Assignment operator. Does not take ownership of data.

         *

         * @param aValue The source object.

         */

         IMPORT_C TAiwVariant& TAiwVariant::operator=(const TAiwVariant& aValue);

         // This class does not need a destructor because memory allocation

         // policy for variant class has been implemented by TAiwGenericParam

         // class.

     public:  // Interface

         /**

         * Returns the type id of data this variant object is holding.

         */

         inline TVariantTypeId TypeId() const;

         /**

         * Returns ETrue if this variant is empty (it does not hold any value).

         */

         inline TBool IsEmpty() const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */

         IMPORT_C TBool Get(TInt32& aValue) const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */        

         IMPORT_C TBool Get(TUid& aValue)   const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */        

         IMPORT_C TBool Get(TPtrC& aValue)  const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */        

         IMPORT_C TBool Get(TTime& aValue)  const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */        

         IMPORT_C TBool Get(TPtrC8& aValue) const;

         /**

         * Retrieves the value held by this variant.

         *

         * @param aValue If this variant's type does not match the

         *               parameter type, the parameter will not be modified.

         * @return ETrue if aValue was set, EFalse if types did not match.

         */        

         IMPORT_C TBool Get(RFile& aValue) const;

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */

         IMPORT_C TInt32 AsTInt32() const;

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */        

         IMPORT_C TUid AsTUid() const;

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */        

         IMPORT_C TPtrC AsDes() const;

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */        

         IMPORT_C TTime AsTTime() const;

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */        

         IMPORT_C TPtrC8 AsData() const; 

         /**

         * Returns the value held by this variant.

         *

         * @return The value held by this variant. If the data type does not

         *         match the function, the default initialized data is returned.

         */        

         IMPORT_C RFile AsFileHandle() const;

         /**

         * Deletes possibly set value and resets this variant to empty.

         *

         * @post IsEmpty()

         */

         IMPORT_C void Reset();

         /**

         * Sets integer value to this variant. The previous value is overwritten.

         *

         * @param aValue Value for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(TInt32 aValue);

         /**

         * Sets unique ID value to this variant. The previous value is overwritten.

         *

         * @param aValue Value for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(const TUid& aValue);

         /**

         * Sets date and time value to this variant. The previous value is overwritten.

         *

         * @param aValue Value for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(const TTime& aValue);

         /**

         * Sets constant text reference to this variant. 

         *

         * @param aValue Text value for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(const TDesC& aValue);

         /**

         * Sets constant text reference to this variant. 

         *

         * @param aValue Text value for this variant object to hold. 

         *               Ownership is not taken.

         */

         inline void Set(const HBufC* aValue);

         /**

         * Sets constant 8-bit text reference to this variant.

         * 

         * @param aValue Text value for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(const TDesC8& aValue);

         /**

         * Sets RFile file handle to this variant.

         *

         * @param aValue File handle for this variant object to hold.

         * @post *this == aValue

         */

         IMPORT_C void Set(const RFile& aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */

         inline TAiwVariant& operator=(const TTime& aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(const TUid& aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(TInt32 aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(const TDesC& aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(const HBufC* aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(const TDesC8& aValue);

         /**

         * Assignment operator for the variant.

         *

         * @param aValue The source object.

         */        

         inline TAiwVariant& operator=(const RFile& aValue);

     private:

         /**

         * Streaming support for TAiwGenericParam.

         * Internalizes this variant from a stream.

         */

         void InternalizeL(RReadStream& aStream);

         /**

         * Streaming support for TAiwGenericParam.

         * Externalizes this variant to a stream.

         */

         void ExternalizeL(RWriteStream& aStream) const;

         /**

         * Streaming support for TAiwGenericParam.

         * Returns the maximum externalized size of this variant in bytes.

         */

         TInt Size() const; 

         /**

         * Data copying support for TAiwGenericParam.

         * Sets the copy of given variant value to this variant

         * @param aValue variant value for this variant object to hold.

         * @post *this == aValue

         */

         void SetL(const TAiwVariant& aValue);

         /**

         * Destroys any dynamic resource owned by this variant.

         */

         void Destroy();

         /// Debug invariant

         void __DbgTestInvariant() const;

     private:  // Data

         /// Type of the data this variant is holding

         TUint8 iTypeId;

         /// POD storage for a 64-bit integer

         struct SInt64

             {

             TInt32 iLow;

             TInt32 iHigh;

             void InternalizeL(RReadStream& aStream);

             void ExternalizeL(RWriteStream& aStream) const;

             void Set(const TInt64& aTInt64);

             operator TInt64() const;

             TBool operator==(const SInt64& aRhs) const;

             };

         // Data value stored in this variant.

         // One of these are effective at a time depending on the iTypeId

         //

         union UData

             {

             TInt32 iInt32;      // 32-bit integer

             SInt64 iInt64;      // 64-bit integer

             HBufC* iBufC;       // owned string pointer 

             HBufC8* iBufC8;     // owned 8-bit data pointer 

             };

         UData  iData;  // Data union

         TPtrC  iPtrC;  // Pointer to string

         TPtrC8 iPtrC8; // Pointer to 8-bit data 

     private:  // friend declarations

         friend IMPORT_C TBool operator==(const TAiwVariant& aLhs, const TAiwVariant& aRhs);

         /// TAiwGenericParam needs access to private streaming and copying methods.

         friend class TAiwGenericParam;

     };

 // FUNCTIONS

 /**

 * Returns ETrue if two variants are equal.

 *

 * @param aLhs Left hand side.

 * @param aRhs Right hand side.

 * @return ETrue if equal, EFalse otherwise.

 */

 IMPORT_C TBool operator==(const TAiwVariant& aLhs, const TAiwVariant& aRhs);

 /**

 * Returns ETrue if two variants are not equal.

 *

 * @param aLhs Left hand side.

 * @param aRhs Right hand side.

 * @return ETrue if not equal, EFalse otherwise.

 */

 inline TBool operator!=(const TAiwVariant& aLhs, const TAiwVariant& aRhs);

 /**

 * Dumps the contents of aVariant to debug output. Available only in debug builds.

 *

 * @param aVariant The object to be dumped.

 */

 void Dump(const TAiwVariant& aVariant);

 // INLINE FUNCTIONS

 #include "AiwVariant.inl"

 #endif // AIW_VARIANT_H

 // End of File