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/*
* Copyright (C) 2012 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.javac.handlers;
import static com.sun.tools.javac.code.Flags.*;
import static lombok.javac.handlers.JavacHandlerUtil.*;
import static lombok.javac.handlers.JavacResolver.*;
import java.util.ArrayList;
import java.util.List;
import javax.lang.model.element.ElementKind;
import lombok.core.AnnotationValues;
import lombok.core.HandlerPriority;
import lombok.experimental.ExtensionMethod;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
import org.mangosdk.spi.ProviderFor;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Type.ClassType;
import com.sun.tools.javac.code.Type.ErrorType;
import com.sun.tools.javac.code.Type.ForAll;
import com.sun.tools.javac.code.Type.MethodType;
import com.sun.tools.javac.code.Types;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
import com.sun.tools.javac.tree.JCTree.JCIdent;
import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
/**
* Handles the {@link ExtensionMethod} annotation for javac.
*/
@ProviderFor(JavacAnnotationHandler.class)
@HandlerPriority(66560) // 2^16 + 2^10; we must run AFTER HandleVal which is at 2^16
public class HandleExtensionMethod extends JavacAnnotationHandler<ExtensionMethod> {
@Override
public void handle(final AnnotationValues<ExtensionMethod> annotation, final JCAnnotation source, final JavacNode annotationNode) {
deleteAnnotationIfNeccessary(annotationNode, ExtensionMethod.class);
JavacNode typeNode = annotationNode.up();
boolean isClassOrEnum = isClassOrEnum(typeNode);
if (!isClassOrEnum) {
annotationNode.addError("@ExtensionMethod can only be used on a class or an enum");
return;
}
boolean suppressBaseMethods = annotation.getInstance().suppressBaseMethods();
List<Object> extensionProviders = annotation.getActualExpressions("value");
if (extensionProviders.isEmpty()) {
annotationNode.addError(String.format("@%s has no effect since no extension types were specified.", ExtensionMethod.class.getName()));
return;
}
final List<Extension> extensions = getExtensions(annotationNode, extensionProviders);
if (extensions.isEmpty()) return;
new ExtensionMethodReplaceVisitor(annotationNode, extensions, suppressBaseMethods).replace();
annotationNode.rebuild();
}
public List<Extension> getExtensions(final JavacNode typeNode, final List<Object> extensionProviders) {
List<Extension> extensions = new ArrayList<Extension>();
for (Object extensionProvider : extensionProviders) {
if (!(extensionProvider instanceof JCFieldAccess)) continue;
JCFieldAccess provider = (JCFieldAccess) extensionProvider;
if (!("class".equals(provider.name.toString()))) continue;
Type providerType = CLASS.resolveMember(typeNode, provider.selected);
if (providerType == null) continue;
if ((providerType.tsym.flags() & (INTERFACE | ANNOTATION)) != 0) continue;
extensions.add(getExtension(typeNode, (ClassType) providerType));
}
return extensions;
}
public Extension getExtension(final JavacNode typeNode, final ClassType extensionMethodProviderType) {
List<MethodSymbol> extensionMethods = new ArrayList<MethodSymbol>();
TypeSymbol tsym = extensionMethodProviderType.asElement();
if (tsym != null) for (Symbol member : tsym.getEnclosedElements()) {
if (member.getKind() != ElementKind.METHOD) continue;
MethodSymbol method = (MethodSymbol) member;
if ((method.flags() & (STATIC | PUBLIC)) == 0) continue;
if (method.params().isEmpty()) continue;
extensionMethods.add(method);
}
return new Extension(extensionMethods, tsym);
}
private static class Extension {
final List<MethodSymbol> extensionMethods;
final TypeSymbol extensionProvider;
public Extension(List<MethodSymbol> extensionMethods, TypeSymbol extensionProvider) {
this.extensionMethods = extensionMethods;
this.extensionProvider = extensionProvider;
}
}
private static class ExtensionMethodReplaceVisitor extends TreeScanner<Void, Void> {
final JavacNode annotationNode;
final List<Extension> extensions;
final boolean suppressBaseMethods;
public ExtensionMethodReplaceVisitor(JavacNode annotationNode, List<Extension> extensions, boolean suppressBaseMethods) {
this.annotationNode = annotationNode;
this.extensions = extensions;
this.suppressBaseMethods = suppressBaseMethods;
}
public void replace() {
annotationNode.up().get().accept(this, null);
}
@Override
public Void visitMethodInvocation(final MethodInvocationTree tree, final Void p) {
handleMethodCall((JCMethodInvocation) tree);
return super.visitMethodInvocation(tree, p);
}
private void handleMethodCall(final JCMethodInvocation methodCall) {
JavacNode methodCallNode = annotationNode.getAst().get(methodCall);
if (methodCallNode == null) {
// This should mean the node does not exist in the source at all. This is the case for generated nodes, such as implicit super() calls.
return;
}
JavacNode surroundingType = upToTypeNode(methodCallNode);
TypeSymbol surroundingTypeSymbol = ((JCClassDecl)surroundingType.get()).sym;
JCExpression receiver = receiverOf(methodCall);
String methodName = methodNameOf(methodCall);
if ("this".equals(methodName) || "super".equals(methodName)) return;
Type resolvedMethodCall = CLASS_AND_METHOD.resolveMember(methodCallNode, methodCall);
if (resolvedMethodCall == null) return;
if (!suppressBaseMethods && !(resolvedMethodCall instanceof ErrorType)) return;
Type receiverType = CLASS_AND_METHOD.resolveMember(methodCallNode, receiver);
if (receiverType == null) return;
if (receiverType.tsym.toString().endsWith(receiver.toString())) return;
Types types = Types.instance(annotationNode.getContext());
for (Extension extension : extensions) {
TypeSymbol extensionProvider = extension.extensionProvider;
if (surroundingTypeSymbol == extensionProvider) continue;
for (MethodSymbol extensionMethod : extension.extensionMethods) {
if (!methodName.equals(extensionMethod.name.toString())) continue;
Type extensionMethodType = extensionMethod.type;
if (!MethodType.class.isInstance(extensionMethodType) && !ForAll.class.isInstance(extensionMethodType)) continue;
Type firstArgType = types.erasure(extensionMethodType.asMethodType().argtypes.get(0));
if (!types.isAssignable(receiverType, firstArgType)) continue;
methodCall.args = methodCall.args.prepend(receiver);
methodCall.meth = chainDotsString(annotationNode, extensionProvider.toString() + "." + methodName);
return;
}
}
}
private String methodNameOf(final JCMethodInvocation methodCall) {
if (methodCall.meth instanceof JCIdent) {
return ((JCIdent) methodCall.meth).name.toString();
} else {
return ((JCFieldAccess) methodCall.meth).name.toString();
}
}
private JCExpression receiverOf(final JCMethodInvocation methodCall) {
if (methodCall.meth instanceof JCIdent) {
return annotationNode.getTreeMaker().Ident(annotationNode.toName("this"));
} else {
return ((JCFieldAccess) methodCall.meth).selected;
}
}
}
}
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