Source code of Windows XP (NT5)
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150 lines
3.8 KiB

//+---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation, 1991 - 2000.
//
// File: Xpr.cxx
//
// Contents: Internal expression classes
//
// Classes: CXpr
//
// History: 11-Sep-91 KyleP Created
//
//----------------------------------------------------------------------------
#include <pch.cxx>
#pragma hdrstop
#include <xpr.hxx>
//+---------------------------------------------------------------------------
//
// Member: CXpr::IsMatch, public
//
// Arguments: [obj] -- Objects table
//
// Returns: FALSE (default)
//
// History: 01-Dec-91 KyleP Created.
//
//----------------------------------------------------------------------------
BOOL CXpr::IsMatch( CRetriever & )
{
return( FALSE );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::HitCount, public
//
// Returns: 0 (default)
//
// History: 01-May-91 KyleP Created.
//
//----------------------------------------------------------------------------
ULONG CXpr::HitCount( CRetriever & )
{
return( 0 );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::Rank, public
//
// Returns: MaxRank (default)
//
// History: 01-May-91 KyleP Created.
//
//----------------------------------------------------------------------------
LONG CXpr::Rank( CRetriever & )
{
return( MAX_QUERY_RANK );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::ValueType, public
//
// Returns: Default value type (PTNone).
//
// History: 26-Nov-91 KyleP Created.
//
//----------------------------------------------------------------------------
ULONG CXpr::ValueType() const
{
return( VT_EMPTY );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::Clone(), public
//
// Returns: A new copy of the expression.
//
// Signals: ???
//
// History: 11-Dec-91 KyleP Created.
//
// Notes: This must be subclassed by every node type which will
// actually be cloned.
//
//----------------------------------------------------------------------------
CXpr * CXpr::Clone()
{
//
// It is illegal to clone an expression which hasn't over-ridden this.
//
Win4Assert( 0 );
return( 0 );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::IsLeaf, public
//
// Synopsis: Determines if an expression is a leaf node.
//
// Returns: TRUE for this default implementation.
//
// History: 11-Dec-91 KyleP Created.
//
//----------------------------------------------------------------------------
BOOL CXpr::IsLeaf() const
{
return( TRUE );
}
//+---------------------------------------------------------------------------
//
// Member: CXpr::GetValue, public
//
// Synopsis: Calculates the value of the expression for the current object.
//
// Arguments: [obj] -- Objects table. Positioned to current object.
// [p] -- Buffer to store value.
// [pcb] -- On input, size of p, on output, return size if
// successful, else required size.
//
// Returns: GVRNotSupported for this default implementation.
//
// History: 11-Dec-91 KyleP Created.
//
// Notes: This is a virtual method of CXpr to make it a simple
// transformation to allow *any* expression to return a
// value instead of just property value expressions.
//
//----------------------------------------------------------------------------
GetValueResult CXpr::GetValue(CRetriever &, PROPVARIANT *, ULONG *)
{
return( GVRNotSupported );
}