/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.javac;
import com.google.gwt.dev.jdt.SafeASTVisitor;
import com.google.gwt.dev.util.InstalledHelpInfo;
import org.eclipse.jdt.core.compiler.CharOperation;
import org.eclipse.jdt.internal.compiler.ast.ASTNode;
import org.eclipse.jdt.internal.compiler.ast.AllocationExpression;
import org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration;
import org.eclipse.jdt.internal.compiler.ast.ConstructorDeclaration;
import org.eclipse.jdt.internal.compiler.ast.FieldDeclaration;
import org.eclipse.jdt.internal.compiler.ast.MethodDeclaration;
import org.eclipse.jdt.internal.compiler.ast.TypeDeclaration;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
import org.eclipse.jdt.internal.compiler.lookup.ClassScope;
import org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope;
import org.eclipse.jdt.internal.compiler.lookup.MethodScope;
import org.eclipse.jdt.internal.compiler.lookup.ReferenceBinding;
import org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding;
import org.eclipse.jdt.internal.compiler.lookup.TypeBinding;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;
/**
* Check a compilation unit for violations of
* {@link com.google.gwt.core.client.JavaScriptObject JavaScriptObject} (JSO)
* restrictions. The restrictions are summarized in
* <code>jsoRestrictions.html</code>.
*
*
* Any violations found are attached as errors on the
* CompilationUnitDeclaration.
*
* @see <a
* href="http://code.google.com/p/google-web-toolkit/wiki/OverlayTypes">Overlay
* types design doc</a>
* @see jsoRestrictions.html
*/
public class JSORestrictionsChecker {
/**
* The order in which the checker will process types is undefined, so this
* type accumulates the information necessary for sanity-checking the JSO
* types.
*/
public static class CheckerState {
private final Map<String, String> interfacesToJsoImpls = new HashMap<String, String>();
public void addJsoInterface(TypeDeclaration jsoType,
CompilationUnitDeclaration cud, ReferenceBinding interf) {
String intfName = CharOperation.toString(interf.compoundName);
String alreadyImplementor = interfacesToJsoImpls.get(intfName);
String myName = CharOperation.toString(jsoType.binding.compoundName);
if (alreadyImplementor == null) {
interfacesToJsoImpls.put(intfName, myName);
} else {
String msg = errAlreadyImplemented(intfName, alreadyImplementor, myName);
errorOn(jsoType, cud, msg);
}
}
public String getJsoImplementor(ReferenceBinding binding) {
String name = CharOperation.toString(binding.compoundName);
return interfacesToJsoImpls.get(name);
}
public boolean isJsoInterface(ReferenceBinding binding) {
String name = CharOperation.toString(binding.compoundName);
return interfacesToJsoImpls.containsKey(name);
}
}
private class JSORestrictionsVisitor extends SafeASTVisitor implements
ClassFileConstants {
private final Stack<Boolean> isJsoStack = new Stack<Boolean>();
@Override
public void endVisit(AllocationExpression exp, BlockScope scope) {
// In rare cases we might not be able to resolve the expression.
if (exp.type == null) {
return;
}
TypeBinding resolvedType = exp.resolvedType;
if (resolvedType == null) {
if (scope == null) {
return;
}
resolvedType = exp.type.resolveType(scope);
}
// Anywhere an allocation occurs is wrong.
if (isJsoSubclass(resolvedType)) {
errorOn(exp, ERR_NEW_JSO);
}
}
@Override
public void endVisit(ConstructorDeclaration meth, ClassScope scope) {
if (!isJso()) {
return;
}
if ((meth.arguments != null) && (meth.arguments.length > 0)) {
errorOn(meth, ERR_CONSTRUCTOR_WITH_PARAMETERS);
}
if ((meth.modifiers & AccProtected) == 0) {
errorOn(meth, ERR_NONPROTECTED_CONSTRUCTOR);
}
if (meth.statements != null && meth.statements.length > 0) {
errorOn(meth, ERR_NONEMPTY_CONSTRUCTOR);
}
}
@Override
public void endVisit(FieldDeclaration field, MethodScope scope) {
if (!isJso()) {
return;
}
if (!field.isStatic()) {
errorOn(field, ERR_INSTANCE_FIELD);
}
}
@Override
public void endVisit(MethodDeclaration meth, ClassScope scope) {
if (!isJso()) {
return;
}
if ((meth.modifiers & (AccFinal | AccPrivate | AccStatic)) == 0) {
// The method's modifiers allow it to be overridden. Make
// one final check to see if the surrounding class is final.
if ((meth.scope == null) || !meth.scope.enclosingSourceType().isFinal()) {
errorOn(meth, ERR_INSTANCE_METHOD_NONFINAL);
}
}
// Should not have to check isStatic() here, but isOverriding() appears
// to be set for static methods.
if (!meth.isStatic()
&& (meth.binding != null && meth.binding.isOverriding())) {
errorOn(meth, ERR_OVERRIDDEN_METHOD);
}
}
@Override
public void endVisit(TypeDeclaration type, ClassScope scope) {
popIsJso();
}
@Override
public void endVisit(TypeDeclaration type, CompilationUnitScope scope) {
popIsJso();
}
@Override
public void endVisitValid(TypeDeclaration type, BlockScope scope) {
popIsJso();
}
@Override
public boolean visit(TypeDeclaration type, ClassScope scope) {
pushIsJso(checkType(type));
return true;
}
@Override
public boolean visit(TypeDeclaration type, CompilationUnitScope scope) {
pushIsJso(checkType(type));
return true;
}
@Override
public boolean visitValid(TypeDeclaration type, BlockScope scope) {
pushIsJso(checkType(type));
return true;
}
private boolean checkType(TypeDeclaration type) {
SourceTypeBinding binding = type.binding;
if (!isJsoSubclass(binding)) {
return false;
}
if (type.enclosingType != null && !binding.isStatic()) {
errorOn(type, ERR_IS_NONSTATIC_NESTED);
}
ReferenceBinding[] interfaces = binding.superInterfaces();
if (interfaces != null) {
for (ReferenceBinding interf : interfaces) {
if (interf.methods() == null) {
continue;
}
if (interf.methods().length > 0) {
// See if any of my superTypes implement it.
ReferenceBinding superclass = binding.superclass();
if (superclass == null
|| !superclass.implementsInterface(interf, true)) {
state.addJsoInterface(type, cud, interf);
}
}
}
}
return true;
}
private boolean isJso() {
return isJsoStack.peek();
}
private void popIsJso() {
isJsoStack.pop();
}
private void pushIsJso(boolean isJso) {
isJsoStack.push(isJso);
}
}
static final String ERR_CONSTRUCTOR_WITH_PARAMETERS = "Constructors must not have parameters in subclasses of JavaScriptObject";
static final String ERR_INSTANCE_FIELD = "Instance fields cannot be used in subclasses of JavaScriptObject";
static final String ERR_INSTANCE_METHOD_NONFINAL = "Instance methods must be 'final' in non-final subclasses of JavaScriptObject";
static final String ERR_IS_NONSTATIC_NESTED = "Nested classes must be 'static' if they extend JavaScriptObject";
static final String ERR_NEW_JSO = "'new' cannot be used to create instances of JavaScriptObject subclasses; instances must originate in JavaScript";
static final String ERR_NONEMPTY_CONSTRUCTOR = "Constructors must be totally empty in subclasses of JavaScriptObject";
static final String ERR_NONPROTECTED_CONSTRUCTOR = "Constructors must be 'protected' in subclasses of JavaScriptObject";
static final String ERR_OVERRIDDEN_METHOD = "Methods cannot be overridden in JavaScriptObject subclasses";
static final String JSO_CLASS = "com/google/gwt/core/client/JavaScriptObject";
/**
* Checks an entire
* {@link org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration}.
*
*/
public static void check(CheckerState state, CompilationUnitDeclaration cud) {
JSORestrictionsChecker checker = new JSORestrictionsChecker(state, cud);
checker.check();
}
/**
* Returns {@code true} if {@code typeBinding} is {@code JavaScriptObject} or
* any subtype.
*/
public static boolean isJso(TypeBinding typeBinding) {
if (!(typeBinding instanceof ReferenceBinding)) {
return false;
}
ReferenceBinding binding = (ReferenceBinding) typeBinding;
while (binding != null) {
if (JSO_CLASS.equals(String.valueOf(binding.constantPoolName()))) {
return true;
}
binding = binding.superclass();
}
return false;
}
/**
* Returns {@code true} if {@code typeBinding} is a subtype of
* {@code JavaScriptObject}, but not {@code JavaScriptObject} itself.
*/
public static boolean isJsoSubclass(TypeBinding typeBinding) {
if (!(typeBinding instanceof ReferenceBinding)) {
return false;
}
ReferenceBinding binding = (ReferenceBinding) typeBinding;
return isJso(binding.superclass());
}
static String errAlreadyImplemented(String intfName, String impl1,
String impl2) {
return "Only one JavaScriptObject type may implement the methods of an "
+ "interface that declared methods. The interface (" + intfName
+ ") is implemented by both (" + impl1 + ") and (" + impl2 + ")";
}
private static void errorOn(ASTNode node, CompilationUnitDeclaration cud,
String error) {
GWTProblem.recordError(node, cud, error, new InstalledHelpInfo(
"jsoRestrictions.html"));
}
private final CompilationUnitDeclaration cud;
private final CheckerState state;
private JSORestrictionsChecker(CheckerState state,
CompilationUnitDeclaration cud) {
this.cud = cud;
this.state = state;
}
private void check() {
cud.traverse(new JSORestrictionsVisitor(), cud.scope);
}
private void errorOn(ASTNode node, String error) {
errorOn(node, cud, error);
}
}