| Methods Summary |
|---|
| public void | addVariable(com.sun.org.apache.xalan.internal.xsltc.compiler.VariableRefBase variableRef)Add new variable to the closure.
if (_closureVars == null) {
_closureVars = new ArrayList();
}
// Only one reference per variable
if (!_closureVars.contains(variableRef)) {
_closureVars.add(variableRef);
// Add variable to parent closure as well
Closure parentClosure = getParentClosure();
if (parentClosure != null) {
parentClosure.addVariable(variableRef);
}
}
|
| private void | compileFilter(com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator classGen, com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator methodGen)Create a new "Filter" class implementing
CurrentNodeListFilter. Allocate registers for local
variables and local parameters passed in the closure to test().
Notice that local variables need to be "unboxed".
TestGenerator testGen;
LocalVariableGen local;
FilterGenerator filterGen;
_className = getXSLTC().getHelperClassName();
filterGen = new FilterGenerator(_className,
"java.lang.Object",
toString(),
ACC_PUBLIC | ACC_SUPER,
new String[] {
CURRENT_NODE_LIST_FILTER
},
classGen.getStylesheet());
final ConstantPoolGen cpg = filterGen.getConstantPool();
final int length = (_closureVars == null) ? 0 : _closureVars.size();
// Add a new instance variable for each var in closure
for (int i = 0; i < length; i++) {
VariableBase var = ((VariableRefBase) _closureVars.get(i)).getVariable();
filterGen.addField(new Field(ACC_PUBLIC,
cpg.addUtf8(var.getEscapedName()),
cpg.addUtf8(var.getType().toSignature()),
null, cpg.getConstantPool()));
}
final InstructionList il = new InstructionList();
testGen = new TestGenerator(ACC_PUBLIC | ACC_FINAL,
com.sun.org.apache.bcel.internal.generic.Type.BOOLEAN,
new com.sun.org.apache.bcel.internal.generic.Type[] {
com.sun.org.apache.bcel.internal.generic.Type.INT,
com.sun.org.apache.bcel.internal.generic.Type.INT,
com.sun.org.apache.bcel.internal.generic.Type.INT,
com.sun.org.apache.bcel.internal.generic.Type.INT,
Util.getJCRefType(TRANSLET_SIG),
Util.getJCRefType(NODE_ITERATOR_SIG)
},
new String[] {
"node",
"position",
"last",
"current",
"translet",
"iterator"
},
"test", _className, il, cpg);
// Store the dom in a local variable
local = testGen.addLocalVariable("document",
Util.getJCRefType(DOM_INTF_SIG),
null, null);
final String className = classGen.getClassName();
il.append(filterGen.loadTranslet());
il.append(new CHECKCAST(cpg.addClass(className)));
il.append(new GETFIELD(cpg.addFieldref(className,
DOM_FIELD, DOM_INTF_SIG)));
il.append(new ASTORE(local.getIndex()));
// Store the dom index in the test generator
testGen.setDomIndex(local.getIndex());
_exp.translate(filterGen, testGen);
il.append(IRETURN);
testGen.stripAttributes(true);
testGen.setMaxLocals();
testGen.setMaxStack();
testGen.removeNOPs();
filterGen.addEmptyConstructor(ACC_PUBLIC);
filterGen.addMethod(testGen.getMethod());
getXSLTC().dumpClass(filterGen.getJavaClass());
|
| public void | dontOptimize()Turns off all optimizations for this predicate.
_canOptimize = false;
|
| public com.sun.org.apache.xalan.internal.xsltc.compiler.Expression | getCompareValue()Returns the value in an expression of the form 'step = value'.
A value may be either a literal string or a variable whose
type is string. Optimization if off if null is returned.
// Returned cached value if called more than once
if (_value != null) {
return _value;
}
// Nothing to to do if _exp is null
if (_exp == null) {
return null;
}
// Ignore if not an equality expression
if (_exp instanceof EqualityExpr) {
EqualityExpr exp = (EqualityExpr) _exp;
Expression left = exp.getLeft();
Expression right = exp.getRight();
// Return if left is literal string
if (left instanceof LiteralExpr) {
_value = left;
return _value;
}
// Return if left is a variable reference of type string
if (left instanceof VariableRefBase &&
left.getType() == Type.String)
{
_value = left;
return _value;
}
// Return if right is literal string
if (right instanceof LiteralExpr) {
_value = right;
return _value;
}
// Return if left is a variable reference whose type is string
if (right instanceof VariableRefBase &&
right.getType() == Type.String)
{
_value = right;
return _value;
}
}
return null;
|
| public com.sun.org.apache.xalan.internal.xsltc.compiler.Expression | getExpr()
return _exp;
|
| public java.lang.String | getInnerClassName()Returns the name of the auxiliary class or null if this predicate
is compiled inside the Translet.
return _className;
|
| public com.sun.org.apache.xalan.internal.xsltc.compiler.Closure | getParentClosure()Returns a reference to its parent closure or null if outermost.
if (_parentClosure == null) {
SyntaxTreeNode node = getParent();
do {
if (node instanceof Closure) {
_parentClosure = (Closure) node;
break;
}
if (node instanceof TopLevelElement) {
break; // way up in the tree
}
node = node.getParent();
} while (node != null);
}
return _parentClosure;
|
| public int | getPosType()Returns the node type of the expression owning this predicate. The
return value is cached in _ptype.
if (_ptype == -1) {
SyntaxTreeNode parent = getParent();
if (parent instanceof StepPattern) {
_ptype = ((StepPattern)parent).getNodeType();
}
else if (parent instanceof AbsoluteLocationPath) {
AbsoluteLocationPath path = (AbsoluteLocationPath)parent;
Expression exp = path.getPath();
if (exp instanceof Step) {
_ptype = ((Step)exp).getNodeType();
}
}
else if (parent instanceof VariableRefBase) {
final VariableRefBase ref = (VariableRefBase)parent;
final VariableBase var = ref.getVariable();
final Expression exp = var.getExpression();
if (exp instanceof Step) {
_ptype = ((Step)exp).getNodeType();
}
}
else if (parent instanceof Step) {
_ptype = ((Step)parent).getNodeType();
}
}
return _ptype;
|
| public com.sun.org.apache.xalan.internal.xsltc.compiler.Step | getStep()Returns the step in an expression of the form 'step = value'.
Null is returned if the expression is not of the right form.
Optimization if off if null is returned.
// Returned cached value if called more than once
if (_step != null) {
return _step;
}
// Nothing to do if _exp is null
if (_exp == null) {
return null;
}
// Ignore if not equality expression
if (_exp instanceof EqualityExpr) {
EqualityExpr exp = (EqualityExpr)_exp;
Expression left = exp.getLeft();
Expression right = exp.getRight();
// Unwrap and set _step if appropriate
if (left instanceof CastExpr) {
left = ((CastExpr) left).getExpr();
}
if (left instanceof Step) {
_step = (Step) left;
}
// Unwrap and set _step if appropriate
if (right instanceof CastExpr) {
right = ((CastExpr)right).getExpr();
}
if (right instanceof Step) {
_step = (Step)right;
}
}
return _step;
|
| public boolean | hasLastCall()Returns true if the expression in this predicate contains a call
to last().
return _exp.hasLastCall();
|
| public boolean | hasPositionCall()Returns true if the expression in this predicate contains a call
to position().
return _exp.hasPositionCall();
|
| public boolean | inInnerClass()Returns true if this closure is compiled in an inner class (i.e.
if this is a real closure).
return (_className != null);
|
| public boolean | isBooleanTest()Returns true if the predicate is a test for the existance of an
element or attribute. All we have to do is to get the first node
from the step, check if it is there, and then return true/false.
return (_exp instanceof BooleanExpr);
|
| public boolean | isNodeValueTest()Method to see if we can optimise the predicate by using a specialised
iterator for expressions like '/foo/bar[@attr = $var]', which are
very common in many stylesheets
if (!_canOptimize) return false;
return (getStep() != null && getCompareValue() != null);
|
| public boolean | isNthDescendant()Returns a boolean value indicating if the nth descendant optimization
is on. Must be call after type checking!
return _nthDescendant;
|
| public boolean | isNthPositionFilter()Returns a boolean value indicating if the nth position optimization
is on. Must be call after type checking!
return _nthPositionFilter;
|
| public boolean | parentIsPattern()
return (getParent() instanceof Pattern);
|
| public void | setParser(com.sun.org.apache.xalan.internal.xsltc.compiler.Parser parser)Set the parser for this expression.
super.setParser(parser);
_exp.setParser(parser);
|
| public java.lang.String | toString()
return "pred(" + _exp + ')";
|
| public void | translate(com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator classGen, com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator methodGen)Translate a predicate expression. If non of the optimizations apply
then this translation pushes two references on the stack: a reference
to a newly created filter object and a reference to the predicate's
closure. See class Step for further details.
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
if (_nthPositionFilter || _nthDescendant) {
_exp.translate(classGen, methodGen);
}
else if (isNodeValueTest() && (getParent() instanceof Step)) {
_value.translate(classGen, methodGen);
il.append(new CHECKCAST(cpg.addClass(STRING_CLASS)));
il.append(new PUSH(cpg, ((EqualityExpr)_exp).getOp()));
}
else {
translateFilter(classGen, methodGen);
}
|
| public void | translateFilter(com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator classGen, com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator methodGen)Translate a predicate expression. This translation pushes
two references on the stack: a reference to a newly created
filter object and a reference to the predicate's closure.
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
// Compile auxiliary class for filter
compileFilter(classGen, methodGen);
// Create new instance of filter
il.append(new NEW(cpg.addClass(_className)));
il.append(DUP);
il.append(new INVOKESPECIAL(cpg.addMethodref(_className,
"<init>", "()V")));
// Initialize closure variables
final int length = (_closureVars == null) ? 0 : _closureVars.size();
for (int i = 0; i < length; i++) {
VariableRefBase varRef = (VariableRefBase) _closureVars.get(i);
VariableBase var = varRef.getVariable();
Type varType = var.getType();
il.append(DUP);
// Find nearest closure implemented as an inner class
Closure variableClosure = _parentClosure;
while (variableClosure != null) {
if (variableClosure.inInnerClass()) break;
variableClosure = variableClosure.getParentClosure();
}
// Use getfield if in an inner class
if (variableClosure != null) {
il.append(ALOAD_0);
il.append(new GETFIELD(
cpg.addFieldref(variableClosure.getInnerClassName(),
var.getEscapedName(), varType.toSignature())));
}
else {
// Use a load of instruction if in translet class
il.append(var.loadInstruction());
}
// Store variable in new closure
il.append(new PUTFIELD(
cpg.addFieldref(_className, var.getEscapedName(),
varType.toSignature())));
}
|
| public com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type | typeCheck(com.sun.org.apache.xalan.internal.xsltc.compiler.SymbolTable stable)Type check a predicate expression. If the type of the expression is
number convert it to boolean by adding a comparison with position().
Note that if the expression is a parameter, we cannot distinguish
at compile time if its type is number or not. Hence, expressions of
reference type are always converted to booleans.
This method may be called twice, before and after calling
dontOptimize(). If so, the second time it should honor
the new value of _canOptimize.
Type texp = _exp.typeCheck(stable);
// We need explicit type information for reference types - no good!
if (texp instanceof ReferenceType) {
_exp = new CastExpr(_exp, texp = Type.Real);
}
// A result tree fragment should not be cast directly to a number type,
// but rather to a boolean value, and then to a numer (0 or 1).
// Ref. section 11.2 of the XSLT 1.0 spec
if (texp instanceof ResultTreeType) {
_exp = new CastExpr(_exp, Type.Boolean);
_exp = new CastExpr(_exp, Type.Real);
texp = _exp.typeCheck(stable);
}
// Numerical types will be converted to a position filter
if (texp instanceof NumberType) {
// Cast any numerical types to an integer
if (texp instanceof IntType == false) {
_exp = new CastExpr(_exp, Type.Int);
}
if (_canOptimize) {
// Nth position optimization. Expression must not depend on context
_nthPositionFilter =
!_exp.hasLastCall() && !_exp.hasPositionCall();
// _nthDescendant optimization - only if _nthPositionFilter is on
if (_nthPositionFilter) {
SyntaxTreeNode parent = getParent();
_nthDescendant = (parent instanceof Step) &&
(parent.getParent() instanceof AbsoluteLocationPath);
return _type = Type.NodeSet;
}
}
// Reset optimization flags
_nthPositionFilter = _nthDescendant = false;
// Otherwise, expand [e] to [position() = e]
final QName position =
getParser().getQNameIgnoreDefaultNs("position");
final PositionCall positionCall =
new PositionCall(position);
positionCall.setParser(getParser());
positionCall.setParent(this);
_exp = new EqualityExpr(EqualityExpr.EQ, positionCall,
_exp);
if (_exp.typeCheck(stable) != Type.Boolean) {
_exp = new CastExpr(_exp, Type.Boolean);
}
return _type = Type.Boolean;
}
else {
// All other types will be handled as boolean values
if (texp instanceof BooleanType == false) {
_exp = new CastExpr(_exp, Type.Boolean);
}
return _type = Type.Boolean;
}
|
