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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
namespace System.Xml.Xsl.Qil
{
/// <summary>A base internal class for QIL visitors.</summary>
/// <remarks>
/// <p>QilVisitor is a base internal class for traversing QIL graphs. Override individual Visit methods to change
/// behavior for only certain node types; override Visit() to change behavior for all node types at once; override
/// VisitChildren() to change the algorithm for iterating and visiting children.</p>
/// <p>Subclasses may also find it useful to annotate the tree during visitation.</p>
/// </remarks>
internal abstract class QilVisitor
{
//-----------------------------------------------
// QilVisitor methods (manually generated)
//-----------------------------------------------
/// <summary>
/// If a reference is passed to the Visit() method, it is assumed to be the definition.
/// This method assumes it is a reference to a definition.
/// For example, if a Let node is visited, is it the Let definition or a reference to the
/// the Let definition? Without context, it is ambiguous. This method allows a caller
/// to disambiguate.
/// </summary>
protected virtual QilNode VisitAssumeReference(QilNode expr)
{
if (expr is QilReference)
return VisitReference(expr);
return Visit(expr);
}
/// <summary>
/// Visit all children of "parent". By default, take care to avoid circular visits.
/// </summary>
protected virtual QilNode VisitChildren(QilNode parent)
{
for (int i = 0; i < parent.Count; i++)
{
// If child is a reference, then call VisitReference instead of Visit in order to avoid circular visits.
if (IsReference(parent, i))
VisitReference(parent[i]);
else
Visit(parent[i]);
}
return parent;
}
/// <summary>
/// Visit all children of "parent". Take care to avoid circular visits.
/// </summary>
protected virtual bool IsReference(QilNode parent, int childNum)
{
QilNode child = parent[childNum];
if (child != null)
{
switch (child.NodeType)
{
case QilNodeType.For:
case QilNodeType.Let:
case QilNodeType.Parameter:
// Is this a reference or a definition?
switch (parent.NodeType)
{
case QilNodeType.Loop:
case QilNodeType.Filter:
case QilNodeType.Sort:
// Second child of these node types is a reference; first child is a definition
return childNum == 1;
case QilNodeType.GlobalVariableList:
case QilNodeType.GlobalParameterList:
case QilNodeType.FormalParameterList:
// All children of definition lists are definitions
return false;
}
// All other cases are references
return true;
case QilNodeType.Function:
// If parent is an Invoke node, then visit a reference to the function
return parent.NodeType == QilNodeType.Invoke;
}
}
return false;
}
//-----------------------------------------------
// QilVisitor methods (auto-generated)
//-----------------------------------------------
// Do not edit this region
#region AUTOGENERATED
protected virtual QilNode Visit(QilNode n)
{
if (n == null)
return VisitNull()!;
return n.NodeType switch
{
QilNodeType.QilExpression => VisitQilExpression((QilExpression)n),
QilNodeType.FunctionList => VisitFunctionList((QilList)n),
QilNodeType.GlobalVariableList => VisitGlobalVariableList((QilList)n),
QilNodeType.GlobalParameterList => VisitGlobalParameterList((QilList)n),
QilNodeType.ActualParameterList => VisitActualParameterList((QilList)n),
QilNodeType.FormalParameterList => VisitFormalParameterList((QilList)n),
QilNodeType.SortKeyList => VisitSortKeyList((QilList)n),
QilNodeType.BranchList => VisitBranchList((QilList)n),
QilNodeType.OptimizeBarrier => VisitOptimizeBarrier((QilUnary)n),
QilNodeType.Unknown => VisitUnknown(n),
QilNodeType.DataSource => VisitDataSource((QilDataSource)n),
QilNodeType.Nop => VisitNop((QilUnary)n),
QilNodeType.Error => VisitError((QilUnary)n),
QilNodeType.Warning => VisitWarning((QilUnary)n),
QilNodeType.For => VisitFor((QilIterator)n),
QilNodeType.Let => VisitLet((QilIterator)n),
QilNodeType.Parameter => VisitParameter((QilParameter)n),
QilNodeType.PositionOf => VisitPositionOf((QilUnary)n),
QilNodeType.True => VisitTrue(n),
QilNodeType.False => VisitFalse(n),
QilNodeType.LiteralString => VisitLiteralString((QilLiteral)n),
QilNodeType.LiteralInt32 => VisitLiteralInt32((QilLiteral)n),
QilNodeType.LiteralInt64 => VisitLiteralInt64((QilLiteral)n),
QilNodeType.LiteralDouble => VisitLiteralDouble((QilLiteral)n),
QilNodeType.LiteralDecimal => VisitLiteralDecimal((QilLiteral)n),
QilNodeType.LiteralQName => VisitLiteralQName((QilName)n),
QilNodeType.LiteralType => VisitLiteralType((QilLiteral)n),
QilNodeType.LiteralObject => VisitLiteralObject((QilLiteral)n),
QilNodeType.And => VisitAnd((QilBinary)n),
QilNodeType.Or => VisitOr((QilBinary)n),
QilNodeType.Not => VisitNot((QilUnary)n),
QilNodeType.Conditional => VisitConditional((QilTernary)n),
QilNodeType.Choice => VisitChoice((QilChoice)n),
QilNodeType.Length => VisitLength((QilUnary)n),
QilNodeType.Sequence => VisitSequence((QilList)n),
QilNodeType.Union => VisitUnion((QilBinary)n),
QilNodeType.Intersection => VisitIntersection((QilBinary)n),
QilNodeType.Difference => VisitDifference((QilBinary)n),
QilNodeType.Average => VisitAverage((QilUnary)n),
QilNodeType.Sum => VisitSum((QilUnary)n),
QilNodeType.Minimum => VisitMinimum((QilUnary)n),
QilNodeType.Maximum => VisitMaximum((QilUnary)n),
QilNodeType.Negate => VisitNegate((QilUnary)n),
QilNodeType.Add => VisitAdd((QilBinary)n),
QilNodeType.Subtract => VisitSubtract((QilBinary)n),
QilNodeType.Multiply => VisitMultiply((QilBinary)n),
QilNodeType.Divide => VisitDivide((QilBinary)n),
QilNodeType.Modulo => VisitModulo((QilBinary)n),
QilNodeType.StrLength => VisitStrLength((QilUnary)n),
QilNodeType.StrConcat => VisitStrConcat((QilStrConcat)n),
QilNodeType.StrParseQName => VisitStrParseQName((QilBinary)n),
QilNodeType.Ne => VisitNe((QilBinary)n),
QilNodeType.Eq => VisitEq((QilBinary)n),
QilNodeType.Gt => VisitGt((QilBinary)n),
QilNodeType.Ge => VisitGe((QilBinary)n),
QilNodeType.Lt => VisitLt((QilBinary)n),
QilNodeType.Le => VisitLe((QilBinary)n),
QilNodeType.Is => VisitIs((QilBinary)n),
QilNodeType.After => VisitAfter((QilBinary)n),
QilNodeType.Before => VisitBefore((QilBinary)n),
QilNodeType.Loop => VisitLoop((QilLoop)n),
QilNodeType.Filter => VisitFilter((QilLoop)n),
QilNodeType.Sort => VisitSort((QilLoop)n),
QilNodeType.SortKey => VisitSortKey((QilSortKey)n),
QilNodeType.DocOrderDistinct => VisitDocOrderDistinct((QilUnary)n),
QilNodeType.Function => VisitFunction((QilFunction)n),
QilNodeType.Invoke => VisitInvoke((QilInvoke)n),
QilNodeType.Content => VisitContent((QilUnary)n),
QilNodeType.Attribute => VisitAttribute((QilBinary)n),
QilNodeType.Parent => VisitParent((QilUnary)n),
QilNodeType.Root => VisitRoot((QilUnary)n),
QilNodeType.XmlContext => VisitXmlContext(n),
QilNodeType.Descendant => VisitDescendant((QilUnary)n),
QilNodeType.DescendantOrSelf => VisitDescendantOrSelf((QilUnary)n),
QilNodeType.Ancestor => VisitAncestor((QilUnary)n),
QilNodeType.AncestorOrSelf => VisitAncestorOrSelf((QilUnary)n),
QilNodeType.Preceding => VisitPreceding((QilUnary)n),
QilNodeType.FollowingSibling => VisitFollowingSibling((QilUnary)n),
QilNodeType.PrecedingSibling => VisitPrecedingSibling((QilUnary)n),
QilNodeType.NodeRange => VisitNodeRange((QilBinary)n),
QilNodeType.Deref => VisitDeref((QilBinary)n),
QilNodeType.ElementCtor => VisitElementCtor((QilBinary)n),
QilNodeType.AttributeCtor => VisitAttributeCtor((QilBinary)n),
QilNodeType.CommentCtor => VisitCommentCtor((QilUnary)n),
QilNodeType.PICtor => VisitPICtor((QilBinary)n),
QilNodeType.TextCtor => VisitTextCtor((QilUnary)n),
QilNodeType.RawTextCtor => VisitRawTextCtor((QilUnary)n),
QilNodeType.DocumentCtor => VisitDocumentCtor((QilUnary)n),
QilNodeType.NamespaceDecl => VisitNamespaceDecl((QilBinary)n),
QilNodeType.RtfCtor => VisitRtfCtor((QilBinary)n),
QilNodeType.NameOf => VisitNameOf((QilUnary)n),
QilNodeType.LocalNameOf => VisitLocalNameOf((QilUnary)n),
QilNodeType.NamespaceUriOf => VisitNamespaceUriOf((QilUnary)n),
QilNodeType.PrefixOf => VisitPrefixOf((QilUnary)n),
QilNodeType.TypeAssert => VisitTypeAssert((QilTargetType)n),
QilNodeType.IsType => VisitIsType((QilTargetType)n),
QilNodeType.IsEmpty => VisitIsEmpty((QilUnary)n),
QilNodeType.XPathNodeValue => VisitXPathNodeValue((QilUnary)n),
QilNodeType.XPathFollowing => VisitXPathFollowing((QilUnary)n),
QilNodeType.XPathPreceding => VisitXPathPreceding((QilUnary)n),
QilNodeType.XPathNamespace => VisitXPathNamespace((QilUnary)n),
QilNodeType.XsltGenerateId => VisitXsltGenerateId((QilUnary)n),
QilNodeType.XsltInvokeLateBound => VisitXsltInvokeLateBound((QilInvokeLateBound)n),
QilNodeType.XsltInvokeEarlyBound => VisitXsltInvokeEarlyBound((QilInvokeEarlyBound)n),
QilNodeType.XsltCopy => VisitXsltCopy((QilBinary)n),
QilNodeType.XsltCopyOf => VisitXsltCopyOf((QilUnary)n),
QilNodeType.XsltConvert => VisitXsltConvert((QilTargetType)n),
_ => VisitUnknown(n),
};
}
protected virtual QilNode VisitReference(QilNode n)
{
if (n == null)
return VisitNull()!;
return n.NodeType switch
{
QilNodeType.For => VisitForReference((QilIterator)n),
QilNodeType.Let => VisitLetReference((QilIterator)n),
QilNodeType.Parameter => VisitParameterReference((QilParameter)n),
QilNodeType.Function => VisitFunctionReference((QilFunction)n),
_ => VisitUnknown(n),
};
}
protected virtual QilNode? VisitNull() { return null; }
#region meta
protected virtual QilNode VisitQilExpression(QilExpression n) { return VisitChildren(n); }
protected virtual QilNode VisitFunctionList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitGlobalVariableList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitGlobalParameterList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitActualParameterList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitFormalParameterList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitSortKeyList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitBranchList(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitOptimizeBarrier(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitUnknown(QilNode n) { return VisitChildren(n); }
#endregion
#region specials
protected virtual QilNode VisitDataSource(QilDataSource n) { return VisitChildren(n); }
protected virtual QilNode VisitNop(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitError(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitWarning(QilUnary n) { return VisitChildren(n); }
#endregion
#region variables
protected virtual QilNode VisitFor(QilIterator n) { return VisitChildren(n); }
protected virtual QilNode VisitForReference(QilIterator n) { return n; }
protected virtual QilNode VisitLet(QilIterator n) { return VisitChildren(n); }
protected virtual QilNode VisitLetReference(QilIterator n) { return n; }
protected virtual QilNode VisitParameter(QilParameter n) { return VisitChildren(n); }
protected virtual QilNode VisitParameterReference(QilParameter n) { return n; }
protected virtual QilNode VisitPositionOf(QilUnary n) { return VisitChildren(n); }
#endregion
#region literals
protected virtual QilNode VisitTrue(QilNode n) { return VisitChildren(n); }
protected virtual QilNode VisitFalse(QilNode n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralString(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralInt32(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralInt64(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralDouble(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralDecimal(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralQName(QilName n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralType(QilLiteral n) { return VisitChildren(n); }
protected virtual QilNode VisitLiteralObject(QilLiteral n) { return VisitChildren(n); }
#endregion
#region boolean operators
protected virtual QilNode VisitAnd(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitOr(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitNot(QilUnary n) { return VisitChildren(n); }
#endregion
#region choice
protected virtual QilNode VisitConditional(QilTernary n) { return VisitChildren(n); }
protected virtual QilNode VisitChoice(QilChoice n) { return VisitChildren(n); }
#endregion
#region collection operators
protected virtual QilNode VisitLength(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitSequence(QilList n) { return VisitChildren(n); }
protected virtual QilNode VisitUnion(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitIntersection(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitDifference(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitAverage(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitSum(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitMinimum(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitMaximum(QilUnary n) { return VisitChildren(n); }
#endregion
#region arithmetic operators
protected virtual QilNode VisitNegate(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitAdd(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitSubtract(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitMultiply(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitDivide(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitModulo(QilBinary n) { return VisitChildren(n); }
#endregion
#region string operators
protected virtual QilNode VisitStrLength(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitStrConcat(QilStrConcat n) { return VisitChildren(n); }
protected virtual QilNode VisitStrParseQName(QilBinary n) { return VisitChildren(n); }
#endregion
#region value comparison operators
protected virtual QilNode VisitNe(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitEq(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitGt(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitGe(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitLt(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitLe(QilBinary n) { return VisitChildren(n); }
#endregion
#region node comparison operators
protected virtual QilNode VisitIs(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitAfter(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitBefore(QilBinary n) { return VisitChildren(n); }
#endregion
#region loops
protected virtual QilNode VisitLoop(QilLoop n) { return VisitChildren(n); }
protected virtual QilNode VisitFilter(QilLoop n) { return VisitChildren(n); }
#endregion
#region sorting
protected virtual QilNode VisitSort(QilLoop n) { return VisitChildren(n); }
protected virtual QilNode VisitSortKey(QilSortKey n) { return VisitChildren(n); }
protected virtual QilNode VisitDocOrderDistinct(QilUnary n) { return VisitChildren(n); }
#endregion
#region function definition and invocation
protected virtual QilNode VisitFunction(QilFunction n) { return VisitChildren(n); }
protected virtual QilNode VisitFunctionReference(QilFunction n) { return n; }
protected virtual QilNode VisitInvoke(QilInvoke n) { return VisitChildren(n); }
#endregion
#region XML navigation
protected virtual QilNode VisitContent(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitAttribute(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitParent(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitRoot(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXmlContext(QilNode n) { return VisitChildren(n); }
protected virtual QilNode VisitDescendant(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitDescendantOrSelf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitAncestor(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitAncestorOrSelf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitPreceding(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitFollowingSibling(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitPrecedingSibling(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitNodeRange(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitDeref(QilBinary n) { return VisitChildren(n); }
#endregion
#region XML construction
protected virtual QilNode VisitElementCtor(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitAttributeCtor(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitCommentCtor(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitPICtor(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitTextCtor(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitRawTextCtor(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitDocumentCtor(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitNamespaceDecl(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitRtfCtor(QilBinary n) { return VisitChildren(n); }
#endregion
#region Node properties
protected virtual QilNode VisitNameOf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitLocalNameOf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitNamespaceUriOf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitPrefixOf(QilUnary n) { return VisitChildren(n); }
#endregion
#region Type operators
protected virtual QilNode VisitTypeAssert(QilTargetType n) { return VisitChildren(n); }
protected virtual QilNode VisitIsType(QilTargetType n) { return VisitChildren(n); }
protected virtual QilNode VisitIsEmpty(QilUnary n) { return VisitChildren(n); }
#endregion
#region XPath operators
protected virtual QilNode VisitXPathNodeValue(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXPathFollowing(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXPathPreceding(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXPathNamespace(QilUnary n) { return VisitChildren(n); }
#endregion
#region XSLT
protected virtual QilNode VisitXsltGenerateId(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXsltInvokeLateBound(QilInvokeLateBound n) { return VisitChildren(n); }
protected virtual QilNode VisitXsltInvokeEarlyBound(QilInvokeEarlyBound n) { return VisitChildren(n); }
protected virtual QilNode VisitXsltCopy(QilBinary n) { return VisitChildren(n); }
protected virtual QilNode VisitXsltCopyOf(QilUnary n) { return VisitChildren(n); }
protected virtual QilNode VisitXsltConvert(QilTargetType n) { return VisitChildren(n); }
#endregion
#endregion // AUTOGENERATED
}
//for checking the depth of QilNode to avoid StackOverflow in visit stage
internal sealed class QilDepthChecker
{
private const int MAX_QIL_DEPTH = 800;
private readonly Dictionary<QilNode, bool> _visitedRef = new Dictionary<QilNode, bool>();
public static void Check(QilNode input)
{
if (LocalAppContextSwitches.LimitXPathComplexity)
{
new QilDepthChecker().Check(input, 0);
}
}
private void Check(QilNode input, int depth)
{
if (depth > MAX_QIL_DEPTH)
{
throw XsltException.Create(SR.Xslt_InputTooComplex);
}
//QilReference node may duplicate, the first one is definition and should expand, others are reference.
if (input is QilReference)
{
if (_visitedRef.ContainsKey(input))
return;
_visitedRef[input] = true;
}
int nextDepth = depth + 1;
for (int i = 0; i < input.Count; i++)
{
QilNode child = input[i];
if (child != null)
{
Check(child, nextDepth);
}
}
}
}
}
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