///<summary>
/// Return the intersection with the target
///</summary>
public override IPermission Intersect(IPermission target)
{
if (target == null)
{
return(null);
}
MediaPermission operand = target as MediaPermission;
if (operand != null)
{
//
// Construct a permission that is the aggregate of the
// least priveleged level of the 3 enums.
//
MediaPermissionAudio audioIntersectLevel = _mediaPermissionAudio < operand._mediaPermissionAudio
? _mediaPermissionAudio : operand._mediaPermissionAudio;
MediaPermissionVideo videoIntersectLevel = _mediaPermissionVideo < operand._mediaPermissionVideo
? _mediaPermissionVideo : operand._mediaPermissionVideo;
MediaPermissionImage imageIntersectLevel = _mediaPermissionImage < operand._mediaPermissionImage
? _mediaPermissionImage : operand._mediaPermissionImage;
if ((audioIntersectLevel == MediaPermissionAudio.NoAudio) &&
(videoIntersectLevel == MediaPermissionVideo.NoVideo) &&
(imageIntersectLevel == MediaPermissionImage.NoImage))
{
return(null);
}
else
{
return(new MediaPermission(audioIntersectLevel, videoIntersectLevel, imageIntersectLevel));
}
}
else
{
throw new ArgumentException(SR.Get(SRID.TargetNotMediaPermissionLevel));
}
}
//
// CodeAccessPermission implementation
//
///<summary>
/// Is this a subsetOf the target ?
///</summary>
public override bool IsSubsetOf(IPermission target)
{
if (target == null)
{
return(EqualsLevel(MediaPermissionAudio.NoAudio,
MediaPermissionVideo.NoVideo,
MediaPermissionImage.NoImage));
}
MediaPermission operand = target as MediaPermission;
if (operand != null)
{
return((this._mediaPermissionAudio <= operand._mediaPermissionAudio) &&
(this._mediaPermissionVideo <= operand._mediaPermissionVideo) &&
(this._mediaPermissionImage <= operand._mediaPermissionImage));
}
else
{
throw new ArgumentException(SR.Get(SRID.TargetNotMediaPermissionLevel));
}
}
CreateMediaAccessPermission(String uri)
{
CodeAccessPermission codeAccessPermission = null;
if (uri != null)
{
// do a Case invariant dotnet culture specific string compare
if (String.Compare(SafeSecurityHelper.IMAGE, uri, true/*Ignore case*/, TypeConverterHelper.InvariantEnglishUS ) == 0)
{
codeAccessPermission = new MediaPermission(MediaPermissionAudio.NoAudio,
MediaPermissionVideo.NoVideo,
MediaPermissionImage.AllImage);
}
else
{
// we allow access to pack: bits so assuming scheme is not pack: we demand
if (String.Compare((System.Windows.Navigation.BaseUriHelper.GetResolvedUri(System.Windows.Navigation.BaseUriHelper.BaseUri, new Uri(uri, UriKind.RelativeOrAbsolute))).Scheme,
PackUriHelper.UriSchemePack, true /* ignore case */,
TypeConverterHelper.InvariantEnglishUS) != 0)
{
// Creating a URI is fine it is going the other way that is risky
if(!SecurityHelper.CallerHasWebPermission(new Uri(uri,UriKind.RelativeOrAbsolute)))
{
codeAccessPermission = new MediaPermission(MediaPermissionAudio.NoAudio,
MediaPermissionVideo.NoVideo,
MediaPermissionImage.AllImage);
}
}
}
}
else
{
codeAccessPermission = new MediaPermission(MediaPermissionAudio.NoAudio,
MediaPermissionVideo.NoVideo,
MediaPermissionImage.AllImage);
}
return codeAccessPermission;
}