/* NOTE: This code depends on the form of Qil expressions generated by XPathPatternBuilder.
* More specifically, it recognizes the following two patterns:
*
* A) /, *, @*, text(), comment(), processing-instruction():
* (And* $x:(IsType RefTo LiteralType))
*
* B) foo, @ns:foo, processing-instruction('foo'):
* (And* $x:(And (IsType RefTo LiteralType) (Eq (NameOf RefTo) LiteralQName)))
*
* where all RefTo refer to 'it', and LiteralType has exactly one NodeKind bit set.
*
* If one of patterns recognized, we nip $x off of the nested And sequence:
* (And* (And2 (And1 $x:* $y:*) $z:*)) => (And* (And2 $y:* $z:*))
*/
private void NipOffTypeNameCheck()
{
QilBinary[] leftPath = new QilBinary[4]; // Circular buffer for last 4 And nodes
int idx = -1; // Index of last element in leftPath
QilNode node = condition; // Walker through left path of the tree
nodeKind = XmlNodeKindFlags.None;
qname = null;
while (node.NodeType == QilNodeType.And)
{
node = (leftPath[++idx & 3] = (QilBinary)node).Left;
}
// Recognizing (IsType RefTo LiteralType)
if (!(node.NodeType == QilNodeType.IsType))
{
return;
}
QilBinary isType = (QilBinary)node;
if (!(isType.Left == iterator && isType.Right.NodeType == QilNodeType.LiteralType))
{
return;
}
XmlNodeKindFlags nodeKinds = isType.Right.XmlType.NodeKinds;
if (!Bits.ExactlyOne((uint)nodeKinds))
{
return;
}
// Recognized pattern A, check for B
QilNode x = isType;
nodeKind = nodeKinds;
QilBinary lastAnd = leftPath[idx & 3];
if (lastAnd != null && lastAnd.Right.NodeType == QilNodeType.Eq)
{
QilBinary eq = (QilBinary)lastAnd.Right;
// Recognizing (Eq (NameOf RefTo) LiteralQName)
if (eq.Left.NodeType == QilNodeType.NameOf &&
((QilUnary)eq.Left).Child == iterator && eq.Right.NodeType == QilNodeType.LiteralQName
)
{
// Recognized pattern B
x = lastAnd;
qname = (QilName)((QilLiteral)eq.Right).Value;
idx--;
}
}
// Nip $x off the condition
QilBinary and1 = leftPath[idx & 3];
QilBinary and2 = leftPath[--idx & 3];
if (and2 != null)
{
and2.Left = and1.Right;
}
else if (and1 != null)
{
condition = and1.Right;
}
else
{
condition = null;
}
}
private bool CheckNamespaceInScope(QilBinary nd)
{
QilName? ndName;
string prefix, ns;
string? prefixExisting, nsExisting;
XPathNodeType nodeType;
switch (nd.NodeType)
{
case QilNodeType.ElementCtor:
case QilNodeType.AttributeCtor:
ndName = nd.Left as QilName;
if (ndName != null)
{
prefix = ndName.Prefix;
ns = ndName.NamespaceUri;
nodeType = (nd.NodeType == QilNodeType.ElementCtor) ? XPathNodeType.Element : XPathNodeType.Attribute;
break;
}
// Not a literal name, so return false
return(false);
default:
Debug.Assert(nd.NodeType == QilNodeType.NamespaceDecl);
prefix = (string)(QilLiteral)nd.Left;
ns = (string)(QilLiteral)nd.Right;
nodeType = XPathNodeType.Namespace;
break;
}
// Attribute with null namespace and xmlns:xml are always in-scope
if (nd.NodeType == QilNodeType.AttributeCtor && ns.Length == 0 ||
prefix == "xml" && ns == XmlReservedNs.NsXml)
{
XmlILConstructInfo.Write(nd).IsNamespaceInScope = true;
return(true);
}
// Don't process names that are invalid
if (!ValidateNames.ValidateName(prefix, string.Empty, ns, nodeType, ValidateNames.Flags.CheckPrefixMapping))
{
return(false);
}
// Atomize names
prefix = _nsmgr.NameTable !.Add(prefix);
ns = _nsmgr.NameTable.Add(ns);
// Determine whether namespace is already in-scope
for (int iNmsp = 0; iNmsp < _cntNmsp; iNmsp++)
{
_nsmgr.GetNamespaceDeclaration(iNmsp, out prefixExisting, out nsExisting);
// If prefix is already declared,
if ((object)prefix == (object?)prefixExisting)
{
// Then if the namespace is the same, this namespace is redundant
if ((object)ns == (object?)nsExisting)
{
XmlILConstructInfo.Write(nd).IsNamespaceInScope = true;
}
// Else quit searching, because any further matching prefixes will be hidden (not in-scope)
Debug.Assert(nd.NodeType != QilNodeType.NamespaceDecl || !_nsmgr.HasNamespace(prefix) || _nsmgr.LookupNamespace(prefix) == ns,
"Compilers must ensure that namespace declarations do not conflict with the namespace used by the element constructor.");
break;
}
}
// If not in-scope, then add if it's allowed
if (_addInScopeNmsp)
{
_nsmgr.AddNamespace(prefix, ns);
_cntNmsp++;
}
return(true);
}
