Bug 176681 Issue about creating context-parameter path in read-only path[0601]
Description: Issue about creating context-parameter path in read-only path Build number:2.2.0.v20070308 Steps to reproduce: 1. Deploy birt. 2. Set BIRT_VIEWER_DOCUMENT_FOLDER/BIRT_VIEWER_IMAGE_DIR/.. to a read-only path. 3. Preview report. Expected result: Because the path is read-only, folders should be created in ${java.io.tmpdir} Actual result: No folders are created in ${java.io.tmpdir} and reports cannot be previewed in frameset mode.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
*/
	public static String processRealPath( ServletContext context, String path,
			String defaultPath, boolean canWrite )
	{
		String realPath = null;
		
		if ( path == null || path.trim( ).length( ) <= 0 )
		{
			path = DataUtil.trimString( defaultPath );
		}
		path = convertSystemPath( path );
		
		if ( isRelativePath( path ) )
		{
			if ( !path.startsWith( "/" ) ) 
				path = "/" + path; 
			realPath = getRealPath( path, context );
			if ( realPath != null && makeDir( realPath ) )
			{
				if ( !canWrite )
					return trimSep( realPath );
				
				try
				{
					if ( canWrite && new File( realPath ).canWrite( ) )
						return trimSep( realPath );
				}
				catch ( Exception e )
				{
				}