private XPathExpr ParsePrimaryExpression()
{
XPathExpr expr = this.ParseVariableExpression();
if ((expr == null) && (this.NextToken(XPathTokenID.LParen) != null))
{
expr = this.ParseExpression();
if ((expr == null) || (this.NextToken(XPathTokenID.RParen) == null))
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
}
if (expr == null)
{
expr = this.ParseLiteralExpression();
}
if (expr == null)
{
expr = this.ParseNumberExpression();
}
if (expr == null)
{
expr = this.ParseFunctionExpression();
}
return(expr);
}
XPathExpr ParseFilterExpression()
{
XPathExpr primaryExpr = this.ParsePrimaryExpression();
if (null == primaryExpr)
{
return(null);
}
XPathExpr filterExpr = new XPathExpr(XPathExprType.Filter, primaryExpr.ReturnType);
filterExpr.Add(primaryExpr);
XPathExpr predicate = this.ParsePredicateExpression();
if (null != predicate)
{
EnsureReturnsNodeSet(primaryExpr);
//XPathExpr filterExpr = new XPathExpr(XPathExprType.Filter, ValueDataType.Sequence);
//filterExpr.Add(primaryExpr);
filterExpr.Add(predicate);
// Read in any additional predicates
while (null != (predicate = this.ParsePredicateExpression()))
{
filterExpr.Add(predicate);
}
return(filterExpr);
}
return(primaryExpr);
}
XPathExpr ParsePrimaryExpression()
{
XPathExpr expr = this.ParseVariableExpression();
if (null == expr)
{
if (null != this.NextToken(XPathTokenID.LParen))
{
expr = this.ParseExpression();
if (null == expr || null == this.NextToken(XPathTokenID.RParen))
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
}
}
if (null == expr)
{
expr = this.ParseLiteralExpression();
}
if (null == expr)
{
expr = this.ParseNumberExpression();
}
if (null == expr)
{
expr = this.ParseFunctionExpression();
}
return(expr);
}
private void CompileFilter(XPathExpr expr)
{
XPathExprList subExpr = expr.SubExpr;
XPathExpr expr2 = subExpr[0];
if ((subExpr.Count > 1) && (ValueDataType.Sequence != expr2.ReturnType))
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
this.CompileExpression(expr2);
if (expr2.ReturnType == ValueDataType.Sequence)
{
if (!this.IsSpecialInternalFunction(expr2) && (expr.SubExprCount > 1))
{
this.codeBlock.Append(new MergeOpcode());
this.codeBlock.Append(new PopSequenceToSequenceStackOpcode());
}
else if (this.IsSpecialInternalFunction(expr2) && (expr.SubExprCount > 1))
{
this.codeBlock.DetachLast();
}
this.compiler.nestingLevel++;
if (this.compiler.nestingLevel > 3)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.PredicateNestingTooDeep));
}
for (int i = 1; i < expr.SubExprCount; i++)
{
this.CompilePredicate(subExpr[i]);
}
this.compiler.nestingLevel--;
}
}
private XPathExpr ParseFilterExpression()
{
XPathExpr expr = this.ParsePrimaryExpression();
if (expr == null)
{
return(null);
}
XPathExpr expr2 = new XPathExpr(XPathExprType.Filter, expr.ReturnType);
expr2.Add(expr);
XPathExpr expr3 = this.ParsePredicateExpression();
if (expr3 == null)
{
return(expr);
}
this.EnsureReturnsNodeSet(expr);
expr2.Add(expr3);
while ((expr3 = this.ParsePredicateExpression()) != null)
{
expr2.Add(expr3);
}
return(expr2);
}
private void CompileXsltFunction(XPathXsltFunctionExpr expr)
{
if (expr.SubExprCount > 0)
{
XPathExprList subExpr = expr.SubExpr;
for (int i = subExpr.Count - 1; i >= 0; i--)
{
XPathExpr expr2 = subExpr[i];
this.CompileExpression(expr2);
ValueDataType destType = XPathXsltFunctionExpr.ConvertTypeFromXslt(expr.Function.ArgTypes[i]);
if ((destType != ValueDataType.None) && (expr2.ReturnType != destType))
{
this.CompileTypecast(destType);
}
}
}
if (expr.Function is XPathMessageFunction)
{
this.codeBlock.Append(new XPathMessageFunctionCallOpcode((XPathMessageFunction)expr.Function, expr.SubExprCount));
if (this.IsSpecialInternalFunction(expr))
{
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
}
else
{
this.codeBlock.Append(new XsltFunctionCallOpcode(expr.Context, expr.Function, expr.SubExprCount));
}
}
// Compiles expressions at nesting level == 1 -> boolean expressions that can be processed
// with less complex opcodes because they will never track multiple sequences simultaneously
void CompileBasicBoolean(XPathExpr expr, bool testValue)
{
// Boolean expressions must always have at least 2 sub expressions
Fx.Assert(expr.SubExprCount > 1, "");
Fx.Assert(this.compiler.nestingLevel == 1, "");
OpcodeBlock boolBlock = new OpcodeBlock(); // struct
Opcode blockEnd = new BlockEndOpcode();
XPathExprList subExprList = expr.SubExpr;
// Compile sub-expressions
for (int i = 0; i < subExprList.Count; ++i)
{
XPathExpr subExpr = subExprList[i];
boolBlock.Append(this.CompileBlock(subExpr));
// Make sure each sub-expression can produce a boolean result
if (subExpr.ReturnType != ValueDataType.Boolean)
{
boolBlock.Append(new TypecastOpcode(ValueDataType.Boolean));
}
if (i < (subExprList.Count - 1))
{
// No point jumping if this is the last expression
boolBlock.Append(new JumpIfOpcode(blockEnd, testValue));
}
}
boolBlock.Append(blockEnd);
this.codeBlock.Append(boolBlock);
}
private void CompileLiteralOrdinal(XPathExpr expr)
{
int ordinal = 0;
try
{
XPathNumberExpr expr2 = (XPathNumberExpr)expr;
ordinal = Convert.ToInt32(expr2.Number);
if (expr2.Negate)
{
ordinal = -ordinal;
expr2.Negate = false;
}
if (ordinal < 1)
{
this.ThrowError(QueryCompileError.InvalidOrdinal);
}
}
catch (OverflowException)
{
this.ThrowError(QueryCompileError.InvalidOrdinal);
}
if ((this.compiler.flags & QueryCompilerFlags.InverseQuery) != QueryCompilerFlags.None)
{
this.codeBlock.Append(new PushContextPositionOpcode());
this.codeBlock.Append(new NumberEqualsOpcode((double)ordinal));
}
else
{
this.codeBlock.Append(new LiteralOrdinalOpcode(ordinal));
}
}
internal static OpcodeBlock CompileForInternalEngine(string xpath, XmlNamespaceManager nsManager, QueryCompilerFlags flags, IFunctionLibrary[] functionLibs, out ValueDataType returnType)
{
OpcodeBlock codeBlock;
returnType = ValueDataType.None;
if (0 == xpath.Length)
{
// 0 length XPaths always match
codeBlock = new OpcodeBlock();
codeBlock.Append(new PushBooleanOpcode(true)); // Always match by pushing true on the eval stack
}
else
{
// Try to parse the xpath. Bind to default function libraries
// The parser returns an expression tree
XPathParser parser = new XPathParser(xpath, nsManager, functionLibs);
XPathExpr parseTree = parser.Parse();
if (null == parseTree)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.CouldNotParseExpression));
}
returnType = parseTree.ReturnType;
// Compile the expression tree
XPathCompiler compiler = new XPathCompiler(flags);
codeBlock = compiler.Compile(parseTree);
}
return(codeBlock);
}
void CompileXsltFunction(XPathXsltFunctionExpr expr)
{
// Compile each argument expression first, introducing a typecast where appropriate
// Arguments are pushed C style - right to left
if (expr.SubExprCount > 0)
{
XPathExprList paramList = expr.SubExpr;
for (int i = paramList.Count - 1; i >= 0; --i)
{
XPathExpr param = paramList[i];
this.CompileExpression(param);
ValueDataType paramType = XPathXsltFunctionExpr.ConvertTypeFromXslt(expr.Function.ArgTypes[i]);
if (ValueDataType.None != paramType)
{
if (param.ReturnType != paramType)
{
this.CompileTypecast(paramType);
}
}
}
}
if (expr.Function is XPathMessageFunction)
{
this.codeBlock.Append(new XPathMessageFunctionCallOpcode((XPathMessageFunction)expr.Function, expr.SubExprCount));
if (IsSpecialInternalFunction(expr))
{
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
}
else
{
this.codeBlock.Append(new XsltFunctionCallOpcode(expr.Context, expr.Function, expr.SubExprCount));
}
}
void CompileRelativePath(XPathExpr expr, bool start)
{
Fx.Assert(XPathExprType.RelativePath == expr.Type, "");
this.CompileSteps(expr.SubExpr, start);
// Step complete. Transfer results onto the value stack
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
private void CompileBoolean(XPathExpr expr, bool testValue)
{
if (this.compiler.nestingLevel == 1)
{
this.CompileBasicBoolean(expr, testValue);
}
else
{
OpcodeBlock block = new OpcodeBlock();
Opcode jump = new BlockEndOpcode();
block.Append(new PushBooleanOpcode(testValue));
XPathExprList subExpr = expr.SubExpr;
XPathExpr expr2 = subExpr[0];
block.Append(this.CompileBlock(expr2));
if (expr2.ReturnType != ValueDataType.Boolean)
{
block.Append(new TypecastOpcode(ValueDataType.Boolean));
}
block.Append(new ApplyBooleanOpcode(jump, testValue));
for (int i = 1; i < subExpr.Count; i++)
{
expr2 = subExpr[i];
block.Append(new StartBooleanOpcode(testValue));
block.Append(this.CompileBlock(expr2));
if (expr2.ReturnType != ValueDataType.Boolean)
{
block.Append(new TypecastOpcode(ValueDataType.Boolean));
}
block.Append(new EndBooleanOpcode(jump, testValue));
}
block.Append(jump);
this.codeBlock.Append(block);
}
}
private void CompileBoolean(XPathExpr expr, bool testValue)
{
if (this.compiler.nestingLevel == 1)
{
this.CompileBasicBoolean(expr, testValue);
}
else
{
OpcodeBlock block = new OpcodeBlock();
Opcode jump = new BlockEndOpcode();
block.Append(new PushBooleanOpcode(testValue));
XPathExprList subExpr = expr.SubExpr;
XPathExpr expr2 = subExpr[0];
block.Append(this.CompileBlock(expr2));
if (expr2.ReturnType != ValueDataType.Boolean)
{
block.Append(new TypecastOpcode(ValueDataType.Boolean));
}
block.Append(new ApplyBooleanOpcode(jump, testValue));
for (int i = 1; i < subExpr.Count; i++)
{
expr2 = subExpr[i];
block.Append(new StartBooleanOpcode(testValue));
block.Append(this.CompileBlock(expr2));
if (expr2.ReturnType != ValueDataType.Boolean)
{
block.Append(new TypecastOpcode(ValueDataType.Boolean));
}
block.Append(new EndBooleanOpcode(jump, testValue));
}
block.Append(jump);
this.codeBlock.Append(block);
}
}
private void TypecastIfRequired(XPathExpr expr)
{
if (expr.TypecastRequired)
{
expr.TypecastRequired = false;
this.CompileTypecast(expr.ReturnType);
}
}
XPathExpr EnsureReturnsNodeSet(XPathExpr expr)
{
if (expr.ReturnType != ValueDataType.Sequence)
{
this.ThrowError(QueryCompileError.InvalidFunction);
}
return(expr);
}
XPathExpr EnsureReturnsNodeSet(XPathExpr expr)
{
if (expr.ReturnType != ValueDataType.Sequence)
{
this.ThrowError(QueryCompileError.InvalidFunction);
}
return expr;
}
private XPathExpr ParseFunctionExpression()
{
XPathExpr expr;
XPathToken token = this.NextToken(XPathTokenID.Function);
if (token == null)
{
return(null);
}
NodeQName name = this.QualifyName(token.Prefix, token.Name);
this.NextToken(XPathTokenID.LParen, QueryCompileError.InvalidFunction);
XPathExprList args = new XPathExprList();
while ((expr = this.ParseExpression()) != null)
{
args.Add(expr);
if (this.NextToken(XPathTokenID.Comma) == null)
{
break;
}
}
XPathExpr expr2 = null;
if (this.functionLibraries != null)
{
QueryFunction function = null;
for (int i = 0; i < this.functionLibraries.Length; i++)
{
function = this.functionLibraries[i].Bind(name.Name, name.Namespace, args);
if (function != null)
{
expr2 = new XPathFunctionExpr(function, args);
break;
}
}
}
if ((expr2 == null) && (this.context != null))
{
XPathResultType[] argTypes = new XPathResultType[args.Count];
for (int j = 0; j < args.Count; j++)
{
argTypes[j] = XPathXsltFunctionExpr.ConvertTypeToXslt(args[j].ReturnType);
}
string prefix = this.context.LookupPrefix(name.Namespace);
IXsltContextFunction function2 = this.context.ResolveFunction(prefix, name.Name, argTypes);
if (function2 != null)
{
expr2 = new XPathXsltFunctionExpr(this.context, function2, args);
}
}
if (expr2 == null)
{
this.ThrowError(QueryCompileError.UnsupportedFunction);
}
this.NextToken(XPathTokenID.RParen, QueryCompileError.InvalidFunction);
return(expr2);
}
internal XPathConjunctExpr(XPathExprType type, ValueDataType returnType, XPathExpr left, XPathExpr right) : base(type, returnType)
{
if ((left == null) || (right == null))
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.InvalidExpression));
}
base.SubExpr.Add(left);
base.SubExpr.Add(right);
}
internal XPathConjunctExpr(XPathExprType type, ValueDataType returnType, XPathExpr left, XPathExpr right) : base(type, returnType)
{
if ((left == null) || (right == null))
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.InvalidExpression));
}
base.SubExpr.Add(left);
base.SubExpr.Add(right);
}
private void NegateIfRequired(XPathExpr expr)
{
this.TypecastIfRequired(expr);
if (expr.Negate)
{
expr.Negate = false;
this.codeBlock.Append(new NegateOpcode());
}
}
void NegateIfRequired(XPathExpr expr)
{
// We can combine these two since the flags they examine are set in exactly one (the same) place.
TypecastIfRequired(expr);
if (expr.Negate)
{
expr.Negate = false;
this.codeBlock.Append(new NegateOpcode());
}
}
private void CompileLocationPath(XPathExpr expr)
{
XPathStepExpr expr2 = (XPathStepExpr)expr.SubExpr[0];
this.CompileSteps(expr.SubExpr);
if (1 == this.compiler.nestingLevel)
{
this.compiler.SetPushInitialContext(expr2.SelectDesc.Type != QueryNodeType.Root);
}
}
XPathExpr ParseRelationalExpression()
{
XPathExpr leftExpr = this.ParseAdditiveExpression();
if (null != leftExpr)
{
RelationOperator op;
do
{
op = RelationOperator.None;
XPathToken token = this.NextToken();
if (null != token)
{
switch (token.TokenID)
{
default:
this.PushToken(token);
break;
case XPathTokenID.Lt:
op = RelationOperator.Lt;
break;
case XPathTokenID.Lte:
op = RelationOperator.Le;
break;
case XPathTokenID.Gt:
op = RelationOperator.Gt;
break;
case XPathTokenID.Gte:
op = RelationOperator.Ge;
break;
}
if (RelationOperator.None != op)
{
XPathExpr rightExpr = this.ParseAdditiveExpression();
if (null == rightExpr)
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
leftExpr = new XPathRelationExpr(op, leftExpr, rightExpr);
}
}
} while (RelationOperator.None != op);
}
return(leftExpr);
}
XPathExpr ParsePathExpression()
{
XPathExpr pathExpr = this.ParseLocationPath();
if (null != pathExpr)
{
return(pathExpr);
}
// Perhaps we have a filter expression
XPathExpr filterExpr = this.ParseFilterExpression();
if (null != filterExpr)
{
if (null != this.NextToken(XPathTokenID.Slash))
{
EnsureReturnsNodeSet(filterExpr);
// Is this a complex filter expression.. i.e. followed by further selections..
XPathExprList relPath = this.ParseRelativePath();
if (null == relPath)
{
this.ThrowError(QueryCompileError.InvalidLocationPath);
}
XPathExpr relPathExpr = new XPathExpr(XPathExprType.RelativePath, ValueDataType.Sequence, relPath);
pathExpr = new XPathExpr(XPathExprType.Path, ValueDataType.Sequence);
pathExpr.Add(filterExpr);
pathExpr.Add(relPathExpr);
}
else if (null != this.NextToken(XPathTokenID.DblSlash))
{
EnsureReturnsNodeSet(filterExpr);
XPathExprList relPath = this.ParseRelativePath();
if (null == relPath)
{
this.ThrowError(QueryCompileError.InvalidLocationPath);
}
XPathExpr relPathExpr = new XPathExpr(XPathExprType.RelativePath, ValueDataType.Sequence, relPath);
pathExpr = new XPathExpr(XPathExprType.Path, ValueDataType.Sequence);
pathExpr.Add(filterExpr);
pathExpr.Add(new XPathStepExpr(new NodeSelectCriteria(QueryAxisType.DescendantOrSelf, NodeQName.Empty, QueryNodeType.All)));
pathExpr.Add(relPathExpr);
}
else
{
pathExpr = filterExpr;
}
}
return(pathExpr);
}
void CompileLocationPath(XPathExpr expr)
{
Fx.Assert(expr.SubExprCount > 0, "");
XPathStepExpr firstStep = (XPathStepExpr)expr.SubExpr[0];
this.CompileSteps(expr.SubExpr);
if (1 == this.compiler.nestingLevel)
{
this.compiler.SetPushInitialContext(firstStep.SelectDesc.Type != QueryNodeType.Root);
}
}
XPathExpr ParseMultiplicativeExpression()
{
XPathExpr leftExpr = this.ParseUnaryExpression();
if (null != leftExpr)
{
MathOperator op;
do
{
op = MathOperator.None;
XPathToken token = this.NextToken();
if (null != token)
{
switch (token.TokenID)
{
default:
this.PushToken(token);
break;
case XPathTokenID.Multiply:
op = MathOperator.Multiply;
break;
case XPathTokenID.Div:
op = MathOperator.Div;
break;
case XPathTokenID.Mod:
op = MathOperator.Mod;
break;
}
if (MathOperator.None != op)
{
XPathExpr rightExpr = this.ParseUnaryExpression();
if (null == rightExpr)
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
leftExpr = new XPathMathExpr(op, leftExpr, rightExpr);
}
}
} while (MathOperator.None != op);
}
return(leftExpr);
}
internal XPathExpr Parse()
{
XPathExpr expr = this.ParseExpression();
if (expr == null)
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
if (this.NextToken() != null)
{
this.ThrowError(QueryCompileError.UnexpectedToken);
}
return(expr);
}
private void CompileFunctionParam(QueryFunction function, XPathExprList paramList, int index)
{
XPathExpr expr = paramList[index];
this.CompileExpression(expr);
if ((function.ParamTypes[index] != ValueDataType.None) && (expr.ReturnType != function.ParamTypes[index]))
{
if (function.ParamTypes[index] == ValueDataType.Sequence)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.InvalidTypeConversion));
}
this.CompileTypecast(function.ParamTypes[index]);
}
}
private bool IsSpecialInternalFunction(XPathExpr expr)
{
if (expr.Type != XPathExprType.XsltFunction)
{
return(false);
}
XPathMessageFunction function = ((XPathXsltFunctionExpr)expr).Function as XPathMessageFunction;
if (function == null)
{
return(false);
}
return((function.ReturnType == XPathResultType.NodeSet) && (function.Maxargs == 0));
}
private XPathExpr ParseRelationalExpression()
{
XPathExpr left = this.ParseAdditiveExpression();
if (left != null)
{
RelationOperator none;
do
{
none = RelationOperator.None;
XPathToken token = this.NextToken();
if (token != null)
{
switch (token.TokenID)
{
case XPathTokenID.Gt:
none = RelationOperator.Gt;
break;
case XPathTokenID.Gte:
none = RelationOperator.Ge;
break;
case XPathTokenID.Lt:
none = RelationOperator.Lt;
break;
case XPathTokenID.Lte:
none = RelationOperator.Le;
break;
default:
this.PushToken(token);
break;
}
if (none != RelationOperator.None)
{
XPathExpr right = this.ParseAdditiveExpression();
if (right == null)
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
left = new XPathRelationExpr(none, left, right);
}
}
}while (none != RelationOperator.None);
}
return(left);
}
internal virtual OpcodeBlock Compile(XPathExpr expr)
{
this.nestingLevel = 1;
this.pushInitialContext = false;
OpcodeBlock block = new XPathExprCompiler(this).Compile(expr);
if (this.pushInitialContext)
{
OpcodeBlock block2 = new OpcodeBlock();
block2.Append(new PushContextNodeOpcode());
block2.Append(block);
block2.Append(new PopContextNodes());
return block2;
}
return block;
}
internal void AddBooleanExpression(XPathExprType boolExprType, XPathExpr expr)
{
if (boolExprType == expr.Type)
{
XPathExprList subExpr = expr.SubExpr;
for (int i = 0; i < subExpr.Count; i++)
{
this.AddBooleanExpression(boolExprType, subExpr[i]);
}
}
else
{
this.Add(expr);
}
}
private XPathExpr ParsePredicateExpression()
{
XPathExpr expr = null;
if (this.NextToken(XPathTokenID.LBracket) != null)
{
expr = this.ParseExpression();
if (expr == null)
{
this.ThrowError(QueryCompileError.InvalidPredicate);
}
this.NextToken(XPathTokenID.RBracket, QueryCompileError.InvalidPredicate);
}
return(expr);
}
internal void AddBooleanExpression(XPathExprType boolExprType, XPathExpr expr)
{
if (boolExprType == expr.Type)
{
XPathExprList subExpr = expr.SubExpr;
for (int i = 0; i < subExpr.Count; i++)
{
this.AddBooleanExpression(boolExprType, subExpr[i]);
}
}
else
{
this.Add(expr);
}
}
private void CompilePath(XPathExpr expr)
{
if (expr.Type == XPathExprType.Filter)
{
this.CompileFilter(expr.SubExpr[0]);
}
else
{
this.CompileExpression(expr.SubExpr[0]);
if (expr.SubExpr[0].ReturnType == ValueDataType.Sequence)
{
if (this.IsSpecialInternalFunction(expr.SubExpr[0]))
{
this.codeBlock.DetachLast();
}
else
{
this.codeBlock.Append(new MergeOpcode());
this.codeBlock.Append(new PopSequenceToSequenceStackOpcode());
}
}
}
if (expr.SubExprCount == 2)
{
this.CompileRelativePath(expr.SubExpr[1], false);
}
else if (expr.SubExprCount == 3)
{
XPathExpr expr2 = expr.SubExpr[1];
XPathStepExpr expr3 = (XPathStepExpr)expr2;
if (!expr3.SelectDesc.Axis.IsSupported())
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.UnsupportedAxis));
}
this.codeBlock.Append(new SelectOpcode(expr3.SelectDesc));
if (expr3.SubExprCount > 0)
{
this.compiler.nestingLevel++;
if (this.compiler.nestingLevel > 3)
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.PredicateNestingTooDeep));
}
this.CompilePredicates(expr3.SubExpr);
this.compiler.nestingLevel--;
}
this.CompileRelativePath(expr.SubExpr[2], false);
}
}
// Compiles top level expressions
internal virtual OpcodeBlock Compile(XPathExpr expr)
{
Fx.Assert(null != expr, "");
this.nestingLevel = 1;
this.pushInitialContext = false;
XPathExprCompiler exprCompiler = new XPathExprCompiler(this);
OpcodeBlock mainBlock = exprCompiler.Compile(expr);
if (this.pushInitialContext)
{
OpcodeBlock expandedBlock = new OpcodeBlock();
expandedBlock.Append(new PushContextNodeOpcode());
expandedBlock.Append(mainBlock);
expandedBlock.Append(new PopContextNodes());
return expandedBlock;
}
return mainBlock;
}
internal OpcodeBlock Compile(XPathExpr expr)
{
this.codeBlock = new OpcodeBlock(); // struct
this.CompileExpression(expr);
return this.codeBlock;
}
void CompileRelativePath(XPathExpr expr, bool start)
{
Fx.Assert(XPathExprType.RelativePath == expr.Type, "");
this.CompileSteps(expr.SubExpr, start);
// Step complete. Transfer results onto the value stack
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
void CompilePredicate(XPathExpr expr)
{
// If the expression does not return a boolean, introduce a typecast
// If the predicate expression is a standalone number literal, interpret it as a literal
if (expr.IsLiteral && XPathExprType.Number == expr.Type)
{
this.CompileLiteralOrdinal(expr);
}
else
{
this.CompileExpression(expr);
if (expr.ReturnType == ValueDataType.Double)
{
this.codeBlock.Append(new OrdinalOpcode());
}
else if (expr.ReturnType != ValueDataType.Boolean)
{
this.CompileTypecast(ValueDataType.Boolean);
}
}
// Apply the results of the predicate on the context sequence
this.codeBlock.Append(new ApplyFilterOpcode());
}
XPathExpr ParseAndExpression()
{
XPathExpr eqExpr = this.ParseEqualityExpression();
if (null != eqExpr && null != this.NextToken(XPathTokenID.And))
{
XPathExpr andExpr = new XPathExpr(XPathExprType.And, ValueDataType.Boolean);
andExpr.AddBooleanExpression(XPathExprType.And, eqExpr);
do
{
eqExpr = this.ParseEqualityExpression();
if (eqExpr == null)
this.ThrowError(QueryCompileError.InvalidExpression);
andExpr.AddBooleanExpression(XPathExprType.And, eqExpr);
} while (null != this.NextToken(XPathTokenID.And));
return andExpr;
}
return eqExpr;
}
internal void Add(XPathExpr expr)
{
Fx.Assert(null != expr, "");
this.list.Add(expr);
}
XPathExpr ParsePathExpression()
{
XPathExpr pathExpr = this.ParseLocationPath();
if (null != pathExpr)
{
return pathExpr;
}
// Perhaps we have a filter expression
XPathExpr filterExpr = this.ParseFilterExpression();
if (null != filterExpr)
{
if (null != this.NextToken(XPathTokenID.Slash))
{
EnsureReturnsNodeSet(filterExpr);
// Is this a complex filter expression.. i.e. followed by further selections..
XPathExprList relPath = this.ParseRelativePath();
if (null == relPath)
{
this.ThrowError(QueryCompileError.InvalidLocationPath);
}
XPathExpr relPathExpr = new XPathExpr(XPathExprType.RelativePath, ValueDataType.Sequence, relPath);
pathExpr = new XPathExpr(XPathExprType.Path, ValueDataType.Sequence);
pathExpr.Add(filterExpr);
pathExpr.Add(relPathExpr);
}
else if (null != this.NextToken(XPathTokenID.DblSlash))
{
EnsureReturnsNodeSet(filterExpr);
XPathExprList relPath = this.ParseRelativePath();
if (null == relPath)
{
this.ThrowError(QueryCompileError.InvalidLocationPath);
}
XPathExpr relPathExpr = new XPathExpr(XPathExprType.RelativePath, ValueDataType.Sequence, relPath);
pathExpr = new XPathExpr(XPathExprType.Path, ValueDataType.Sequence);
pathExpr.Add(filterExpr);
pathExpr.Add(new XPathStepExpr(new NodeSelectCriteria(QueryAxisType.DescendantOrSelf, NodeQName.Empty, QueryNodeType.All)));
pathExpr.Add(relPathExpr);
}
else
{
pathExpr = filterExpr;
}
}
return pathExpr;
}
OpcodeBlock CompileBlock(XPathExpr expr)
{
XPathExprCompiler compiler = new XPathExprCompiler(this);
return compiler.Compile(expr);
}
bool IsSpecialInternalFunction(XPathExpr expr)
{
if (expr.Type != XPathExprType.XsltFunction)
{
return false;
}
XPathMessageFunction func = ((XPathXsltFunctionExpr)expr).Function as XPathMessageFunction;
if (func != null)
{
return func.ReturnType == XPathResultType.NodeSet && func.Maxargs == 0;
}
return false;
}
XPathExpr ParseOrExpression()
{
XPathExpr andExpr = this.ParseAndExpression();
if (null != andExpr && null != this.NextToken(XPathTokenID.Or))
{
XPathExpr orExpr = new XPathExpr(XPathExprType.Or, ValueDataType.Boolean);
orExpr.AddBooleanExpression(XPathExprType.Or, andExpr);
do
{
andExpr = this.ParseAndExpression();
if (andExpr == null)
this.ThrowError(QueryCompileError.InvalidExpression);
orExpr.AddBooleanExpression(XPathExprType.Or, andExpr);
} while (null != this.NextToken(XPathTokenID.Or));
return orExpr;
}
return andExpr;
}
XPathExpr ParseFilterExpression()
{
XPathExpr primaryExpr = this.ParsePrimaryExpression();
if (null == primaryExpr)
{
return null;
}
XPathExpr filterExpr = new XPathExpr(XPathExprType.Filter, primaryExpr.ReturnType);
filterExpr.Add(primaryExpr);
XPathExpr predicate = this.ParsePredicateExpression();
if (null != predicate)
{
EnsureReturnsNodeSet(primaryExpr);
//XPathExpr filterExpr = new XPathExpr(XPathExprType.Filter, ValueDataType.Sequence);
//filterExpr.Add(primaryExpr);
filterExpr.Add(predicate);
// Read in any additional predicates
while (null != (predicate = this.ParsePredicateExpression()))
{
filterExpr.Add(predicate);
}
return filterExpr;
}
return primaryExpr;
}
// Compiles expressions at nesting level == 1 -> boolean expressions that can be processed
// with less complex opcodes because they will never track multiple sequences simultaneously
void CompileBasicBoolean(XPathExpr expr, bool testValue)
{
// Boolean expressions must always have at least 2 sub expressions
Fx.Assert(expr.SubExprCount > 1, "");
Fx.Assert(this.compiler.nestingLevel == 1, "");
OpcodeBlock boolBlock = new OpcodeBlock(); // struct
Opcode blockEnd = new BlockEndOpcode();
XPathExprList subExprList = expr.SubExpr;
// Compile sub-expressions
for (int i = 0; i < subExprList.Count; ++i)
{
XPathExpr subExpr = subExprList[i];
boolBlock.Append(this.CompileBlock(subExpr));
// Make sure each sub-expression can produce a boolean result
if (subExpr.ReturnType != ValueDataType.Boolean)
{
boolBlock.Append(new TypecastOpcode(ValueDataType.Boolean));
}
if (i < (subExprList.Count - 1))
{
// No point jumping if this is the last expression
boolBlock.Append(new JumpIfOpcode(blockEnd, testValue));
}
}
boolBlock.Append(blockEnd);
this.codeBlock.Append(boolBlock);
}
internal void Add(XPathExpr expr)
{
this.list.Add(expr);
}
internal XPathRelationExpr(RelationOperator op, XPathExpr left, XPathExpr right) : base(XPathExprType.Relational, ValueDataType.Boolean, left, right)
{
this.op = op;
}
void NegateIfRequired(XPathExpr expr)
{
// We can combine these two since the flags they examine are set in exactly one (the same) place.
TypecastIfRequired(expr);
if (expr.Negate)
{
expr.Negate = false;
this.codeBlock.Append(new NegateOpcode());
}
}
void TypecastIfRequired(XPathExpr expr)
{
if (expr.TypecastRequired)
{
expr.TypecastRequired = false;
CompileTypecast(expr.ReturnType);
}
}
void CompileLiteralOrdinal(XPathExpr expr)
{
int ordinal = 0;
try
{
XPathNumberExpr numExpr = (XPathNumberExpr)expr;
ordinal = Convert.ToInt32(numExpr.Number);
if (numExpr.Negate)
{
ordinal = -ordinal;
numExpr.Negate = false;
}
if (ordinal < 1)
{
this.ThrowError(QueryCompileError.InvalidOrdinal);
}
}
catch (OverflowException)
{
this.ThrowError(QueryCompileError.InvalidOrdinal);
}
if (0 != (this.compiler.flags & QueryCompilerFlags.InverseQuery))
{
this.codeBlock.Append(new PushContextPositionOpcode());
this.codeBlock.Append(new NumberEqualsOpcode(ordinal));
}
else
{
this.codeBlock.Append(new LiteralOrdinalOpcode(ordinal));
}
}
void CompileBoolean(XPathExpr expr, bool testValue)
{
// Boolean expressions must always have at least 2 sub expressions
Fx.Assert(expr.SubExprCount > 1, "");
if (this.compiler.nestingLevel == 1)
{
this.CompileBasicBoolean(expr, testValue);
return;
}
OpcodeBlock boolBlock = new OpcodeBlock(); // struct
Opcode blockEnd = new BlockEndOpcode();
// Set up the result mask
boolBlock.Append(new PushBooleanOpcode(testValue));
XPathExprList subExprList = expr.SubExpr;
XPathExpr subExpr;
// the first expression needs the least work..
subExpr = subExprList[0];
boolBlock.Append(this.CompileBlock(subExpr));
if (subExpr.ReturnType != ValueDataType.Boolean)
{
boolBlock.Append(new TypecastOpcode(ValueDataType.Boolean));
}
boolBlock.Append(new ApplyBooleanOpcode(blockEnd, testValue));
// Compile remaining sub-expressions
for (int i = 1; i < subExprList.Count; ++i)
{
subExpr = subExprList[i];
boolBlock.Append(new StartBooleanOpcode(testValue));
boolBlock.Append(this.CompileBlock(subExpr));
// Make sure each sub-expression can produce a boolean result
if (subExpr.ReturnType != ValueDataType.Boolean)
{
boolBlock.Append(new TypecastOpcode(ValueDataType.Boolean));
}
boolBlock.Append(new EndBooleanOpcode(blockEnd, testValue));
}
boolBlock.Append(blockEnd);
this.codeBlock.Append(boolBlock);
}
void CompileLocationPath(XPathExpr expr)
{
Fx.Assert(expr.SubExprCount > 0, "");
XPathStepExpr firstStep = (XPathStepExpr)expr.SubExpr[0];
this.CompileSteps(expr.SubExpr);
if (1 == this.compiler.nestingLevel)
{
this.compiler.SetPushInitialContext(firstStep.SelectDesc.Type != QueryNodeType.Root);
}
}
internal void AddBooleanExpression(XPathExprType boolExprType, XPathExpr expr)
{
Fx.Assert(boolExprType == this.type, "");
// An boolean sub0expression that is of the same type as its container should be merged and flattened
// into its parent
if (boolExprType == expr.Type)
{
XPathExprList subExprList = expr.SubExpr;
for (int i = 0; i < subExprList.Count; ++i)
{
this.AddBooleanExpression(boolExprType, subExprList[i]);
}
}
else
{
this.Add(expr);
}
}
void CompilePath(XPathExpr expr)
{
Fx.Assert(expr.SubExprCount == 2 || expr.SubExprCount == 3, "");
if (expr.Type == XPathExprType.Filter)
{
this.CompileFilter(expr.SubExpr[0]);
}
else
{
this.CompileExpression(expr.SubExpr[0]);
if (expr.SubExpr[0].ReturnType == ValueDataType.Sequence)
{
if (IsSpecialInternalFunction(expr.SubExpr[0]))
{
this.codeBlock.DetachLast();
}
else
{
this.codeBlock.Append(new MergeOpcode());
this.codeBlock.Append(new PopSequenceToSequenceStackOpcode());
}
}
}
if (expr.SubExprCount == 2)
{
this.CompileRelativePath(expr.SubExpr[1], false);
}
else if (expr.SubExprCount == 3)
{
// Compile the step
XPathExpr e = expr.SubExpr[1];
Fx.Assert(XPathExprType.PathStep == e.Type, "");
XPathStepExpr step = (XPathStepExpr)e;
Fx.Assert(QueryNodeType.Root != step.SelectDesc.Type, "");
if (!step.SelectDesc.Axis.IsSupported())
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.UnsupportedAxis));
}
this.codeBlock.Append(new SelectOpcode(step.SelectDesc));
// The step may have predicates..
if (step.SubExprCount > 0)
{
this.compiler.nestingLevel++;
if (this.compiler.nestingLevel > 3) // throw if we find something deepter than [ [ ] ]
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.PredicateNestingTooDeep));
}
this.CompilePredicates(step.SubExpr);
this.compiler.nestingLevel--;
}
// Compile the relative path
this.CompileRelativePath(expr.SubExpr[2], false);
}
}
void CompileExpression(XPathExpr expr)
{
Fx.Assert(null != expr, "");
switch (expr.Type)
{
default:
this.ThrowError(QueryCompileError.UnsupportedExpression);
break;
case XPathExprType.And:
this.CompileBoolean(expr, true);
break;
case XPathExprType.Or:
this.CompileBoolean(expr, false);
break;
case XPathExprType.Relational:
this.CompileRelational((XPathRelationExpr)expr);
break;
case XPathExprType.Function:
this.CompileFunction((XPathFunctionExpr)expr);
break;
case XPathExprType.Union:
{
XPathConjunctExpr unionExpr = (XPathConjunctExpr)expr;
this.CompileExpression(unionExpr.Left);
this.CompileExpression(unionExpr.Right);
this.codeBlock.Append(new UnionOpcode());
}
break;
case XPathExprType.RelativePath:
this.CompileRelativePath(expr, true);
break;
case XPathExprType.LocationPath:
if (expr.SubExprCount > 0)
{
this.CompileLocationPath(expr);
// Step complete. Transfer results onto the value stack
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
break;
case XPathExprType.Math:
this.CompileMath((XPathMathExpr)expr);
break;
case XPathExprType.Number:
XPathNumberExpr number = (XPathNumberExpr)expr;
double literal = number.Number;
if (number.Negate)
{
number.Negate = false;
literal = -literal;
}
this.codeBlock.Append(new PushNumberOpcode(literal));
break;
case XPathExprType.String:
this.codeBlock.Append(new PushStringOpcode(((XPathStringExpr)expr).String));
break;
case XPathExprType.Filter:
this.CompileFilter(expr);
if (expr.ReturnType == ValueDataType.Sequence)
{
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
break;
case XPathExprType.Path:
this.CompilePath(expr);
if (expr.SubExprCount == 0 && expr.ReturnType == ValueDataType.Sequence)
{
this.codeBlock.Append(new PopSequenceToValueStackOpcode());
}
break;
case XPathExprType.XsltFunction:
this.CompileXsltFunction((XPathXsltFunctionExpr)expr);
break;
case XPathExprType.XsltVariable:
this.CompileXsltVariable((XPathXsltVariableExpr)expr);
break;
}
NegateIfRequired(expr);
}
internal void Add(XPathExpr expr)
{
this.SubExpr.Add(expr);
}
void CompileFilter(XPathExpr expr)
{
Fx.Assert(XPathExprType.Filter == expr.Type, "");
// The filter expression has two components - the expression and its predicate
// It may have an optional relative path following it
//Debug.Assert(expr.SubExprCount <= 3);
XPathExprList subExpr = expr.SubExpr;
XPathExpr filterExpr = subExpr[0];
if (subExpr.Count > 1 && ValueDataType.Sequence != filterExpr.ReturnType)
{
this.ThrowError(QueryCompileError.InvalidExpression);
}
// The filter expression will return a sequence and push it onto the value stack
// Transfer it back to the sequence stack, so we can keep working on it
this.CompileExpression(filterExpr);
if (filterExpr.ReturnType == ValueDataType.Sequence)
{
if (!IsSpecialInternalFunction(filterExpr) && expr.SubExprCount > 1)
{
// Flatten the sequence and move it to the sequence stack
this.codeBlock.Append(new MergeOpcode());
this.codeBlock.Append(new PopSequenceToSequenceStackOpcode());
}
else if (IsSpecialInternalFunction(filterExpr) && expr.SubExprCount > 1)
{
this.codeBlock.DetachLast();
}
// Now, apply the predicates
this.compiler.nestingLevel++;
if (this.compiler.nestingLevel > 3) // throw if we find something deepter than [ [ ] ]
{
throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(new QueryCompileException(QueryCompileError.PredicateNestingTooDeep));
}
for (int i = 1; i < expr.SubExprCount; ++i)
{
this.CompilePredicate(subExpr[i]);
}
this.compiler.nestingLevel--;
}
}
internal XPathMathExpr(MathOperator op, XPathExpr left, XPathExpr right)
: base(XPathExprType.Math, ValueDataType.Double, left, right)
{
this.op = op;
}
