/*******************************************************************************
* Copyright (c) 2000, 2011 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.wst.jsdt.internal.compiler.flow;
import org.eclipse.wst.jsdt.internal.compiler.ast.ASTNode;
import org.eclipse.wst.jsdt.internal.compiler.ast.Expression;
import org.eclipse.wst.jsdt.internal.compiler.ast.Reference;
import org.eclipse.wst.jsdt.internal.compiler.lookup.BlockScope;
import org.eclipse.wst.jsdt.internal.compiler.lookup.LocalVariableBinding;
import org.eclipse.wst.jsdt.internal.compiler.lookup.Scope;
import org.eclipse.wst.jsdt.internal.compiler.lookup.VariableBinding;
/**
* Reflects the context of code analysis, keeping track of enclosing
* try statements, exception handlers, etc...
*/
public class FinallyFlowContext extends FlowContext {
Reference[] finalAssignments;
VariableBinding[] finalVariables;
int assignCount;
LocalVariableBinding[] nullLocals;
Expression[] nullReferences;
int[] nullCheckTypes;
int nullCount;
public FinallyFlowContext(FlowContext parent, ASTNode associatedNode) {
super(parent, associatedNode);
}
/**
* Given some contextual initialization info (derived from a try block or a catch block), this
* code will check that the subroutine context does not also initialize a final variable potentially set
* redundantly.
*/
public void complainOnDeferredChecks(FlowInfo flowInfo, BlockScope scope) {
// check inconsistent null checks
if (this.deferNullDiagnostic) { // within an enclosing loop, be conservative
for (int i = 0; i < this.nullCount; i++) {
this.parent.recordUsingNullReference(scope, this.nullLocals[i],
this.nullReferences[i], this.nullCheckTypes[i], flowInfo);
}
}
else { // no enclosing loop, be as precise as possible right now
for (int i = 0; i < this.nullCount; i++) {
Expression expression = this.nullReferences[i];
// final local variable
LocalVariableBinding local = this.nullLocals[i];
switch (this.nullCheckTypes[i]) {
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL:
if (flowInfo.isDefinitelyNonNull(local)) {
if (this.nullCheckTypes[i] == (CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL)) {
scope.problemReporter().localVariableRedundantCheckOnNonNull(local, expression);
} else {
scope.problemReporter().localVariableNonNullComparedToNull(local, expression);
}
continue;
}
case CAN_ONLY_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL | IN_COMPARISON_NON_NULL:
case CAN_ONLY_NULL | IN_ASSIGNMENT:
case CAN_ONLY_NULL | IN_INSTANCEOF:
if (flowInfo.isDefinitelyNull(local)) {
switch(this.nullCheckTypes[i] & CONTEXT_MASK) {
case FlowContext.IN_COMPARISON_NULL:
scope.problemReporter().localVariableRedundantCheckOnNull(local, expression);
continue;
case FlowContext.IN_COMPARISON_NON_NULL:
scope.problemReporter().localVariableNullComparedToNonNull(local, expression);
continue;
case FlowContext.IN_ASSIGNMENT:
scope.problemReporter().localVariableRedundantNullAssignment(local, expression);
continue;
case FlowContext.IN_INSTANCEOF:
scope.problemReporter().localVariableNullInstanceof(local, expression);
continue;
}
}
break;
case MAY_NULL:
if (flowInfo.isDefinitelyNull(local)) {
scope.problemReporter().localVariableNullReference(local, expression);
continue;
}
if (flowInfo.isPotentiallyNull(local)) {
scope.problemReporter().localVariablePotentialNullReference(local, expression);
}
break;
default:
// should not happen
}
}
}
}
public String individualToString() {
StringBuffer buffer = new StringBuffer("Finally flow context"); //$NON-NLS-1$
buffer.append("[finalAssignments count - ").append(assignCount).append(']'); //$NON-NLS-1$
buffer.append("[nullReferences count - ").append(nullCount).append(']'); //$NON-NLS-1$
return buffer.toString();
}
public boolean isSubRoutine() {
return true;
}
protected boolean recordFinalAssignment(
VariableBinding binding,
Reference finalAssignment) {
if (assignCount == 0) {
finalAssignments = new Reference[5];
finalVariables = new VariableBinding[5];
} else {
if (assignCount == finalAssignments.length)
System.arraycopy(
finalAssignments,
0,
(finalAssignments = new Reference[assignCount * 2]),
0,
assignCount);
System.arraycopy(
finalVariables,
0,
(finalVariables = new VariableBinding[assignCount * 2]),
0,
assignCount);
}
finalAssignments[assignCount] = finalAssignment;
finalVariables[assignCount++] = binding;
return true;
}
public void recordUsingNullReference(Scope scope, LocalVariableBinding local,
Expression reference, int checkType, FlowInfo flowInfo) {
if ((flowInfo.tagBits & FlowInfo.UNREACHABLE) == 0 && !flowInfo.isDefinitelyUnknown(local)) {
if (deferNullDiagnostic) { // within an enclosing loop, be conservative
switch (checkType) {
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL:
case CAN_ONLY_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL | IN_COMPARISON_NON_NULL:
case CAN_ONLY_NULL | IN_ASSIGNMENT:
case CAN_ONLY_NULL | IN_INSTANCEOF:
if (flowInfo.cannotBeNull(local)) {
if (checkType == (CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL)) {
scope.problemReporter().localVariableRedundantCheckOnNonNull(local, reference);
} else {
scope.problemReporter().localVariableNonNullComparedToNull(local, reference);
}
return;
}
if (flowInfo.canOnlyBeNull(local)) {
switch(checkType & CONTEXT_MASK) {
case FlowContext.IN_COMPARISON_NULL:
scope.problemReporter().localVariableRedundantCheckOnNull(local, reference);
return;
case FlowContext.IN_COMPARISON_NON_NULL:
scope.problemReporter().localVariableNullComparedToNonNull(local, reference);
return;
case FlowContext.IN_ASSIGNMENT:
scope.problemReporter().localVariableRedundantNullAssignment(local, reference);
return;
case FlowContext.IN_INSTANCEOF:
scope.problemReporter().localVariableNullInstanceof(local, reference);
return;
}
}
break;
case MAY_NULL :
if (flowInfo.cannotBeNull(local)) {
return;
}
if (flowInfo.canOnlyBeNull(local)) {
scope.problemReporter().localVariableNullReference(local, reference);
return;
}
break;
default:
// never happens
}
}
else { // no enclosing loop, be as precise as possible right now
switch (checkType) {
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL:
if (flowInfo.isDefinitelyNonNull(local)) {
if (checkType == (CAN_ONLY_NULL_NON_NULL | IN_COMPARISON_NON_NULL)) {
scope.problemReporter().localVariableRedundantCheckOnNonNull(local, reference);
} else {
scope.problemReporter().localVariableNonNullComparedToNull(local, reference);
}
return;
}
case CAN_ONLY_NULL | IN_COMPARISON_NULL:
case CAN_ONLY_NULL | IN_COMPARISON_NON_NULL:
case CAN_ONLY_NULL | IN_ASSIGNMENT:
case CAN_ONLY_NULL | IN_INSTANCEOF:
if (flowInfo.isDefinitelyNull(local)) {
switch(checkType & CONTEXT_MASK) {
case FlowContext.IN_COMPARISON_NULL:
scope.problemReporter().localVariableRedundantCheckOnNull(local, reference);
return;
case FlowContext.IN_COMPARISON_NON_NULL:
scope.problemReporter().localVariableNullComparedToNonNull(local, reference);
return;
case FlowContext.IN_ASSIGNMENT:
scope.problemReporter().localVariableRedundantNullAssignment(local, reference);
return;
case FlowContext.IN_INSTANCEOF:
scope.problemReporter().localVariableNullInstanceof(local, reference);
return;
}
}
break;
case MAY_NULL :
if (flowInfo.isDefinitelyNull(local)) {
scope.problemReporter().localVariableNullReference(local, reference);
return;
}
if (flowInfo.isPotentiallyNull(local)) {
scope.problemReporter().localVariablePotentialNullReference(local, reference);
return;
}
if (flowInfo.isDefinitelyNonNull(local)) {
return; // shortcut: cannot be null
}
break;
default:
// never happens
}
}
recordNullReference(local, reference, checkType);
// prepare to re-check with try/catch flow info
}
}
void removeFinalAssignmentIfAny(Reference reference) {
for (int i = 0; i < assignCount; i++) {
if (finalAssignments[i] == reference) {
finalAssignments[i] = null;
finalVariables[i] = null;
return;
}
}
}
protected void recordNullReference(LocalVariableBinding local,
Expression expression, int status) {
if (this.nullCount == 0) {
this.nullLocals = new LocalVariableBinding[5];
this.nullReferences = new Expression[5];
this.nullCheckTypes = new int[5];
}
else if (this.nullCount == this.nullLocals.length) {
int newLength = this.nullCount * 2;
System.arraycopy(this.nullLocals, 0,
this.nullLocals = new LocalVariableBinding[newLength], 0,
this.nullCount);
System.arraycopy(this.nullReferences, 0,
this.nullReferences = new Expression[newLength], 0,
this.nullCount);
System.arraycopy(this.nullCheckTypes, 0,
this.nullCheckTypes = new int[newLength], 0,
this.nullCount);
}
this.nullLocals[this.nullCount] = local;
this.nullReferences[this.nullCount] = expression;
this.nullCheckTypes[this.nullCount++] = status;
}
}