/*******************************************************************************
* Copyright (c) 2004 IBM Corporation and others.
* All rights reserved. The initial API is made available under the terms of
* the Common Public License v1.0 which is available at:
* http://www.eclipse.org/legal/cpl-v10.html
* Subsequent modifications are made available under the Apache 2.0 license.
*
* Contributors:
* IBM - Initial API and implementation
* Groovy community - subsequent modifications
******************************************************************************/
package org.codehaus.groovy.classgen;
import java.util.List;
import org.codehaus.groovy.ast.*;
import org.codehaus.groovy.ast.expr.BinaryExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.DeclarationExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.GStringExpression;
import org.codehaus.groovy.ast.expr.MapEntryExpression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.expr.PropertyExpression;
import org.codehaus.groovy.ast.expr.TupleExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.ast.stmt.CatchStatement;
import org.codehaus.groovy.control.SourceUnit;
import org.objectweb.asm.Opcodes;
import org.codehaus.groovy.runtime.MetaClassHelper;
import org.codehaus.groovy.syntax.Types;
import static java.lang.reflect.Modifier.*;
/**
* ClassCompletionVerifier
*/
public class ClassCompletionVerifier extends ClassCodeVisitorSupport implements Opcodes {
private ClassNode currentClass;
private SourceUnit source;
private boolean inConstructor = false;
private boolean inStaticConstructor = false;
public ClassCompletionVerifier(SourceUnit source) {
this.source = source;
}
public ClassNode getClassNode() {
return currentClass;
}
public void visitClass(ClassNode node) {
ClassNode oldClass = currentClass;
currentClass = node;
checkImplementsAndExtends(node);
if (source != null && !source.getErrorCollector().hasErrors()) {
checkClassForIncorrectModifiers(node);
checkInterfaceMethodVisibility(node);
checkClassForOverwritingFinal(node);
checkMethodsForIncorrectModifiers(node);
checkMethodsForWeakerAccess(node);
checkMethodsForOverridingFinal(node);
checkNoAbstractMethodsNonabstractClass(node);
}
super.visitClass(node);
currentClass = oldClass;
}
private void checkInterfaceMethodVisibility(ClassNode node) {
if (!node.isInterface()) return;
for (MethodNode method : node.getMethods()) {
if (method.isPrivate()) {
addError("Method '" + method.getName() + "' is private but should be public in " + getDescription(currentClass) + ".", method);
} else if (method.isProtected()) {
addError("Method '" + method.getName() + "' is protected but should be public in " + getDescription(currentClass) + ".", method);
}
}
}
private void checkNoAbstractMethodsNonabstractClass(ClassNode node) {
if (isAbstract(node.getModifiers())) return;
List<MethodNode> abstractMethods = node.getAbstractMethods();
if (abstractMethods == null) return;
for (MethodNode method : abstractMethods) {
addError("Can't have an abstract method in a non-abstract class." +
" The " + getDescription(node) + " must be declared abstract or" +
" the " + getDescription(method) + " must be implemented.", node);
}
}
private void checkClassForIncorrectModifiers(ClassNode node) {
checkClassForAbstractAndFinal(node);
checkClassForOtherModifiers(node);
}
private void checkClassForAbstractAndFinal(ClassNode node) {
if (!isAbstract(node.getModifiers())) return;
if (!isFinal(node.getModifiers())) return;
if (node.isInterface()) {
addError("The " + getDescription(node) + " must not be final. It is by definition abstract.", node);
} else {
addError("The " + getDescription(node) + " must not be both final and abstract.", node);
}
}
private void checkClassForOtherModifiers(ClassNode node) {
checkClassForModifier(node, isTransient(node.getModifiers()), "transient");
checkClassForModifier(node, isVolatile(node.getModifiers()), "volatile");
checkClassForModifier(node, isNative(node.getModifiers()), "native");
if (!(node instanceof InnerClassNode)) {
checkClassForModifier(node, isStatic(node.getModifiers()), "static");
}
// don't check synchronized here as it overlaps with ACC_SUPER
}
private void checkMethodForModifier(MethodNode node, boolean condition, String modifierName) {
if (!condition) return;
addError("The " + getDescription(node) + " has an incorrect modifier " + modifierName + ".", node);
}
private void checkClassForModifier(ClassNode node, boolean condition, String modifierName) {
if (!condition) return;
addError("The " + getDescription(node) + " has an incorrect modifier " + modifierName + ".", node);
}
private String getDescription(ClassNode node) {
return (node.isInterface() ? "interface" : "class") + " '" + node.getName() + "'";
}
private String getDescription(MethodNode node) {
return "method '" + node.getTypeDescriptor() + "'";
}
private String getDescription(FieldNode node) {
return "field '" + node.getName() + "'";
}
private void checkAbstractDeclaration(MethodNode methodNode) {
if (!methodNode.isAbstract()) return;
if (isAbstract(currentClass.getModifiers())) return;
addError("Can't have an abstract method in a non-abstract class." +
" The " + getDescription(currentClass) + " must be declared abstract or the method '" +
methodNode.getTypeDescriptor() + "' must not be abstract.", methodNode);
}
private void checkClassForOverwritingFinal(ClassNode cn) {
ClassNode superCN = cn.getSuperClass();
if (superCN == null) return;
if (!isFinal(superCN.getModifiers())) return;
StringBuilder msg = new StringBuilder();
msg.append("You are not allowed to overwrite the final ");
msg.append(getDescription(superCN));
msg.append(".");
addError(msg.toString(), cn);
}
private void checkImplementsAndExtends(ClassNode node) {
ClassNode cn = node.getSuperClass();
if (cn.isInterface() && !node.isInterface()) {
addError("You are not allowed to extend the " + getDescription(cn) + ", use implements instead.", node);
}
for (ClassNode anInterface : node.getInterfaces()) {
cn = anInterface;
if (!cn.isInterface()) {
addError("You are not allowed to implement the " + getDescription(cn) + ", use extends instead.", node);
}
}
}
private void checkMethodsForIncorrectModifiers(ClassNode cn) {
if (!cn.isInterface()) return;
for (MethodNode method : cn.getMethods()) {
if (isFinal(method.getModifiers())) {
addError("The " + getDescription(method) + " from " + getDescription(cn) +
" must not be final. It is by definition abstract.", method);
}
if (method.isStatic() && !isConstructor(method)) {
addError("The " + getDescription(method) + " from " + getDescription(cn) +
" must not be static. Only fields may be static in an interface.", method);
}
}
}
private void checkMethodsForWeakerAccess(ClassNode cn) {
for (MethodNode method : cn.getMethods()) {
checkMethodForWeakerAccessPrivileges(method, cn);
}
}
private boolean isConstructor(MethodNode method) {
return method.getName().equals("<clinit>");
}
private void checkMethodsForOverridingFinal(ClassNode cn) {
for (MethodNode method : cn.getMethods()) {
Parameter[] params = method.getParameters();
for (MethodNode superMethod : cn.getSuperClass().getMethods(method.getName())) {
Parameter[] superParams = superMethod.getParameters();
if (!hasEqualParameterTypes(params, superParams)) continue;
if (!isFinal(superMethod.getModifiers())) break;
addInvalidUseOfFinalError(method, params, superMethod.getDeclaringClass());
return;
}
}
}
private void addInvalidUseOfFinalError(MethodNode method, Parameter[] parameters, ClassNode superCN) {
StringBuilder msg = new StringBuilder();
msg.append("You are not allowed to override the final method ").append(method.getName());
msg.append("(");
boolean needsComma = false;
for (Parameter parameter : parameters) {
if (needsComma) {
msg.append(",");
} else {
needsComma = true;
}
msg.append(parameter.getType());
}
msg.append(") from ").append(getDescription(superCN));
msg.append(".");
addError(msg.toString(), method);
}
private void addWeakerAccessError(ClassNode cn, MethodNode method, Parameter[] parameters, MethodNode superMethod) {
StringBuilder msg = new StringBuilder();
msg.append(method.getName());
msg.append("(");
boolean needsComma = false;
for (Parameter parameter : parameters) {
if (needsComma) {
msg.append(",");
} else {
needsComma = true;
}
msg.append(parameter.getType());
}
msg.append(") in ");
msg.append(cn.getName());
msg.append(" cannot override ");
msg.append(superMethod.getName());
msg.append(" in ");
msg.append(superMethod.getDeclaringClass().getName());
msg.append("; attempting to assign weaker access privileges; was ");
msg.append(superMethod.isPublic() ? "public" : "protected");
addError(msg.toString(), method);
}
private boolean hasEqualParameterTypes(Parameter[] first, Parameter[] second) {
if (first.length != second.length) return false;
for (int i = 0; i < first.length; i++) {
String ft = first[i].getType().getName();
String st = second[i].getType().getName();
if (ft.equals(st)) continue;
return false;
}
return true;
}
protected SourceUnit getSourceUnit() {
return source;
}
public void visitMethod(MethodNode node) {
inConstructor = false;
inStaticConstructor = node.isStaticConstructor();
checkAbstractDeclaration(node);
checkRepetitiveMethod(node);
checkOverloadingPrivateAndPublic(node);
checkMethodModifiers(node);
super.visitMethod(node);
}
private void checkMethodModifiers(MethodNode node) {
// don't check volatile here as it overlaps with ACC_BRIDGE
// additional modifiers not allowed for interfaces
if ((this.currentClass.getModifiers() & ACC_INTERFACE) != 0) {
checkMethodForModifier(node, isStrict(node.getModifiers()), "strictfp");
checkMethodForModifier(node, isSynchronized(node.getModifiers()), "synchronized");
checkMethodForModifier(node, isNative(node.getModifiers()), "native");
}
}
private void checkMethodForWeakerAccessPrivileges(MethodNode mn, ClassNode cn) {
Parameter[] params = mn.getParameters();
for (MethodNode superMethod : cn.getSuperClass().getMethods(mn.getName())) {
Parameter[] superParams = superMethod.getParameters();
if (!hasEqualParameterTypes(params, superParams)) continue;
if ((mn.isPrivate() && !superMethod.isPrivate()) ||
(mn.isProtected() && superMethod.isPublic())) {
addWeakerAccessError(cn, mn, params, superMethod);
return;
}
}
}
private void checkOverloadingPrivateAndPublic(MethodNode node) {
if (isConstructor(node)) return;
boolean hasPrivate = false;
boolean hasPublic = false;
for (MethodNode method : currentClass.getMethods(node.getName())) {
if (method == node) continue;
if (!method.getDeclaringClass().equals(node.getDeclaringClass())) continue;
if (method.isPublic() || method.isProtected()) {
hasPublic = true;
} else {
hasPrivate = true;
}
}
if (hasPrivate && hasPublic) {
addError("Mixing private and public/protected methods of the same name causes multimethods to be disabled and is forbidden to avoid surprising behaviour. Renaming the private methods will solve the problem.", node);
}
}
private void checkRepetitiveMethod(MethodNode node) {
if (isConstructor(node)) return;
for (MethodNode method : currentClass.getMethods(node.getName())) {
if (method == node) continue;
if (!method.getDeclaringClass().equals(node.getDeclaringClass())) continue;
Parameter[] p1 = node.getParameters();
Parameter[] p2 = method.getParameters();
if (p1.length != p2.length) continue;
addErrorIfParamsAndReturnTypeEqual(p2, p1, node, method);
}
}
private void addErrorIfParamsAndReturnTypeEqual(Parameter[] p2, Parameter[] p1,
MethodNode node, MethodNode element) {
boolean isEqual = true;
for (int i = 0; i < p2.length; i++) {
isEqual &= p1[i].getType().equals(p2[i].getType());
}
isEqual &= node.getReturnType().equals(element.getReturnType());
if (isEqual) {
addError("Repetitive method name/signature for " + getDescription(node) +
" in " + getDescription(currentClass) + ".", node);
}
}
public void visitField(FieldNode node) {
if (currentClass.getDeclaredField(node.getName()) != node) {
addError("The " + getDescription(node) + " is declared multiple times.", node);
}
checkInterfaceFieldModifiers(node);
super.visitField(node);
}
public void visitProperty(PropertyNode node) {
checkDuplicateProperties(node);
super.visitProperty(node);
}
private void checkDuplicateProperties(PropertyNode node) {
ClassNode cn = node.getDeclaringClass();
String name = node.getName();
String getterName = "get" + MetaClassHelper.capitalize(name);
if (Character.isUpperCase(name.charAt(0))) {
for (PropertyNode propNode : cn.getProperties()) {
String otherName = propNode.getField().getName();
String otherGetterName = "get" + MetaClassHelper.capitalize(otherName);
if (node != propNode && getterName.equals(otherGetterName)) {
String msg = "The field " + name + " and " + otherName + " on the class " +
cn.getName() + " will result in duplicate JavaBean properties, which is not allowed";
addError(msg, node);
}
}
}
}
private void checkInterfaceFieldModifiers(FieldNode node) {
if (!currentClass.isInterface()) return;
if ((node.getModifiers() & (ACC_PUBLIC | ACC_STATIC | ACC_FINAL)) == 0 ||
(node.getModifiers() & (ACC_PRIVATE | ACC_PROTECTED)) != 0) {
addError("The " + getDescription(node) + " is not 'public static final' but is defined in " +
getDescription(currentClass) + ".", node);
}
}
public void visitBinaryExpression(BinaryExpression expression) {
if (expression.getOperation().getType() == Types.LEFT_SQUARE_BRACKET &&
expression.getRightExpression() instanceof MapEntryExpression) {
addError("You tried to use a map entry for an index operation, this is not allowed. " +
"Maybe something should be set in parentheses or a comma is missing?",
expression.getRightExpression());
}
super.visitBinaryExpression(expression);
switch (expression.getOperation().getType()) {
case Types.EQUAL: // = assignment
case Types.BITWISE_AND_EQUAL:
case Types.BITWISE_OR_EQUAL:
case Types.BITWISE_XOR_EQUAL:
case Types.PLUS_EQUAL:
case Types.MINUS_EQUAL:
case Types.MULTIPLY_EQUAL:
case Types.DIVIDE_EQUAL:
case Types.INTDIV_EQUAL:
case Types.MOD_EQUAL:
case Types.POWER_EQUAL:
case Types.LEFT_SHIFT_EQUAL:
case Types.RIGHT_SHIFT_EQUAL:
case Types.RIGHT_SHIFT_UNSIGNED_EQUAL:
checkFinalFieldAccess(expression.getLeftExpression());
break;
default:
break;
}
}
private void checkFinalFieldAccess(Expression expression) {
if (!(expression instanceof VariableExpression) && !(expression instanceof PropertyExpression)) return;
Variable v = null;
if (expression instanceof VariableExpression) {
VariableExpression ve = (VariableExpression) expression;
v = ve.getAccessedVariable();
} else {
PropertyExpression propExp = ((PropertyExpression) expression);
Expression objectExpression = propExp.getObjectExpression();
if (objectExpression instanceof VariableExpression) {
VariableExpression varExp = (VariableExpression) objectExpression;
if (varExp.isThisExpression()) {
v = currentClass.getDeclaredField(propExp.getPropertyAsString());
}
}
}
if (v instanceof FieldNode) {
FieldNode fn = (FieldNode) v;
/*
* if it is static final but not accessed inside a static constructor, or,
* if it is an instance final but not accessed inside a instance constructor, it is an error
*/
boolean isFinal = fn.isFinal();
boolean isStatic = fn.isStatic();
boolean error = isFinal && ((isStatic && !inStaticConstructor) || (!isStatic && !inConstructor));
if (error) addError("cannot modify" + (isStatic ? " static" : "") + " final field '" + fn.getName() +
"' outside of " + (isStatic ? "static initialization block." : "constructor."), expression);
}
}
public void visitConstructor(ConstructorNode node) {
inConstructor = true;
inStaticConstructor = node.isStaticConstructor();
super.visitConstructor(node);
}
public void visitCatchStatement(CatchStatement cs) {
if (!(cs.getExceptionType().isDerivedFrom(ClassHelper.make(Throwable.class)))) {
addError("Catch statement parameter type is not a subclass of Throwable.", cs);
}
super.visitCatchStatement(cs);
}
public void visitMethodCallExpression(MethodCallExpression mce) {
super.visitMethodCallExpression(mce);
Expression aexp = mce.getArguments();
if (aexp instanceof TupleExpression) {
TupleExpression arguments = (TupleExpression) aexp;
for (Expression e : arguments.getExpressions()) {
checkForInvalidDeclaration(e);
}
} else {
checkForInvalidDeclaration(aexp);
}
}
@Override
public void visitDeclarationExpression(DeclarationExpression expression) {
super.visitDeclarationExpression(expression);
if (expression.isMultipleAssignmentDeclaration()) return;
checkInvalidDeclarationModifier(expression, ACC_ABSTRACT, "abstract");
checkInvalidDeclarationModifier(expression, ACC_NATIVE, "native");
checkInvalidDeclarationModifier(expression, ACC_PRIVATE, "private");
checkInvalidDeclarationModifier(expression, ACC_PROTECTED, "protected");
checkInvalidDeclarationModifier(expression, ACC_PUBLIC, "public");
checkInvalidDeclarationModifier(expression, ACC_STATIC, "static");
checkInvalidDeclarationModifier(expression, ACC_STRICT, "strictfp");
checkInvalidDeclarationModifier(expression, ACC_SYNCHRONIZED, "synchronized");
checkInvalidDeclarationModifier(expression, ACC_TRANSIENT, "transient");
checkInvalidDeclarationModifier(expression, ACC_VOLATILE, "volatile");
}
private void checkInvalidDeclarationModifier(DeclarationExpression expression, int modifier, String modName) {
if ((expression.getVariableExpression().getModifiers() & modifier) != 0) {
addError("Modifier '" + modName + "' not allowed here.", expression);
}
}
private void checkForInvalidDeclaration(Expression exp) {
if (!(exp instanceof DeclarationExpression)) return;
addError("Invalid use of declaration inside method call.", exp);
}
public void visitConstantExpression(ConstantExpression expression) {
super.visitConstantExpression(expression);
checkStringExceedingMaximumLength(expression);
}
public void visitGStringExpression(GStringExpression expression) {
super.visitGStringExpression(expression);
for (ConstantExpression ce : expression.getStrings()) {
checkStringExceedingMaximumLength(ce);
}
}
private void checkStringExceedingMaximumLength(ConstantExpression expression) {
Object value = expression.getValue();
if (value instanceof String) {
String s = (String) value;
if (s.length() > 65535) {
addError("String too long. The given string is " + s.length() + " Unicode code units long, but only a maximum of 65535 is allowed.", expression);
}
}
}
}