/*
* SonarQube JavaScript Plugin
* Copyright (C) 2011 SonarSource and Eriks Nukis
* dev@sonar.codehaus.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02
*/
package org.sonar.javascript.checks;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Maps;
import com.sonar.sslr.api.AstNode;
import com.sonar.sslr.api.AstNodeType;
import com.sonar.sslr.api.AstVisitor;
import com.sonar.sslr.impl.ast.AstWalker;
import org.sonar.check.Priority;
import org.sonar.check.Rule;
import org.sonar.javascript.api.EcmaScriptTokenType;
import org.sonar.javascript.checks.utils.FunctionUtils;
import org.sonar.javascript.checks.utils.IdentifierUtils;
import org.sonar.javascript.parser.EcmaScriptGrammar;
import org.sonar.squidbridge.checks.SquidCheck;
import org.sonar.sslr.parser.LexerlessGrammar;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
@Rule(
key = "VariableShadowing",
priority = Priority.MAJOR)
public class VariableShadowingCheck extends SquidCheck<LexerlessGrammar> {
private Map<AstNode, Scope> scopes;
private static class Scope {
private final Scope outerScope;
private Map<String, AstNode> declaration = Maps.newHashMap();
public Scope() {
this.outerScope = null;
}
public Scope(Scope outerScope) {
this.outerScope = outerScope;
}
private void declare(AstNode astNode) {
Preconditions.checkState(astNode.is(EcmaScriptTokenType.IDENTIFIER));
String identifier = astNode.getTokenValue();
if (!declaration.containsKey(identifier)) {
declaration.put(identifier, astNode);
}
}
}
private static final AstNodeType[] CONST_AND_VAR_NODES = {
EcmaScriptGrammar.VARIABLE_DECLARATION,
EcmaScriptGrammar.VARIABLE_DECLARATION_NO_IN,
EcmaScriptGrammar.LEXICAL_BINDING,
EcmaScriptGrammar.LEXICAL_BINDING_NO_IN};
private Scope currentScope;
@Override
public void init() {
subscribeTo(EcmaScriptGrammar.FORMAL_PARAMETER_LIST);
subscribeTo(FunctionUtils.getFunctionNodes());
subscribeTo(CONST_AND_VAR_NODES);
}
@Override
public void visitFile(AstNode astNode) {
if (astNode != null) {
scopes = Maps.newHashMap();
new AstWalker(new InnerVisitor()).walkAndVisit(astNode);
currentScope = scopes.get(astNode);
}
}
@Override
public void visitNode(AstNode astNode) {
if (astNode.is(FunctionUtils.getFunctionNodes())) {
// enter new scope
currentScope = scopes.get(astNode);
} else if (astNode.is(EcmaScriptGrammar.FORMAL_PARAMETER_LIST)) {
checkIdentifiers(IdentifierUtils.getParametersIdentifier(astNode));
} else if (astNode.is(CONST_AND_VAR_NODES)) {
checkIdentifiers(IdentifierUtils.getVariableIdentifiers(astNode));
}
}
private void check(AstNode astNode) {
Preconditions.checkState(astNode.is(EcmaScriptTokenType.IDENTIFIER));
String identifier = astNode.getTokenValue();
Scope scope = currentScope.outerScope;
while (scope != null) {
if (scope.declaration.containsKey(identifier)) {
getContext().createLineViolation(this, "\"" + identifier + "\" hides variable declared in outer scope.", astNode);
break;
}
scope = scope.outerScope;
}
}
@Override
public void leaveNode(AstNode astNode) {
if (astNode.is(FunctionUtils.getFunctionNodes())) {
// leave scope
currentScope = currentScope.outerScope;
}
}
@Override
public void leaveFile(AstNode astNode) {
currentScope = null;
scopes = null;
}
private void checkIdentifiers(List<AstNode> identifiers) {
for (AstNode identifier : identifiers) {
check(identifier);
}
}
private class InnerVisitor implements AstVisitor {
private Scope currentScope;
public List<AstNodeType> getAstNodeTypesToVisit() {
return ImmutableList.<AstNodeType>builder()
.add(EcmaScriptGrammar.FORMAL_PARAMETER_LIST)
.addAll(Arrays.asList(CONST_AND_VAR_NODES))
.addAll(Arrays.asList(FunctionUtils.getFunctionNodes())).build();
}
@Override
public void visitFile(AstNode astNode) {
currentScope = new Scope();
scopes.put(astNode, currentScope);
}
@Override
public void visitNode(AstNode astNode) {
if (astNode.is(FunctionUtils.getFunctionNodes())) {
// enter new scope
currentScope = new Scope(currentScope);
scopes.put(astNode, currentScope);
} else if (astNode.is(EcmaScriptGrammar.FORMAL_PARAMETER_LIST)) {
declareInCurrentScope(IdentifierUtils.getParametersIdentifier(astNode));
} else if (astNode.is(CONST_AND_VAR_NODES)) {
declareInCurrentScope(IdentifierUtils.getVariableIdentifiers(astNode));
}
}
private void declareInCurrentScope(List<AstNode> identifiers) {
for (AstNode identifier : identifiers) {
currentScope.declare(identifier);
}
}
@Override
public void leaveNode(AstNode astNode) {
if (astNode.is(FunctionUtils.getFunctionNodes())) {
// leave scope
currentScope = currentScope.outerScope;
}
}
@Override
public void leaveFile(AstNode astNode) {
// nop
}
}
}