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/*
* Copyright (C) 2013 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 lombok.javac.Javac.*;
import static lombok.javac.handlers.JavacHandlerUtil.*;
import org.mangosdk.spi.ProviderFor;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCBinary;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCIdent;
import com.sun.tools.javac.tree.JCTree.JCIf;
import com.sun.tools.javac.tree.JCTree.JCLiteral;
import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
import com.sun.tools.javac.tree.JCTree.JCParens;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCThrow;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;
import lombok.NonNull;
import lombok.core.AnnotationValues;
import lombok.core.AST.Kind;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
@ProviderFor(JavacAnnotationHandler.class)
public class NonNullHandler extends JavacAnnotationHandler<NonNull> {
@Override public void handle(AnnotationValues<NonNull> annotation, JCAnnotation ast, JavacNode annotationNode) {
if (annotationNode.up().getKind() == Kind.FIELD) {
// This is meaningless unless the field is used to generate a method (@Setter, @RequiredArgsConstructor, etc),
// but in that case those handlers will take care of it. However, we DO check if the annotation is applied to
// a primitive, because those handlers trigger on any annotation named @NonNull and we only want the warning
// behaviour on _OUR_ 'lombok.NonNull'.
try {
if (isPrimitive(((JCVariableDecl) annotationNode.up().get()).vartype)) {
annotationNode.addWarning("@NonNull is meaningless on a primitive.");
}
} catch (Exception ignore) {}
return;
}
if (annotationNode.up().getKind() != Kind.ARGUMENT) return;
JCMethodDecl declaration;
try {
declaration = (JCMethodDecl) annotationNode.up().up().get();
} catch (Exception e) {
return;
}
if (JavacHandlerUtil.isGenerated(declaration)) return;
// Possibly, if 'declaration instanceof ConstructorDeclaration', fetch declaration.constructorCall, search it for any references to our parameter,
// and if they exist, create a new method in the class: 'private static <T> T lombok$nullCheck(T expr, String msg) {if (expr == null) throw NPE; return expr;}' and
// wrap all references to it in the super/this to a call to this method.
JCStatement nullCheck = recursiveSetGeneratedBy(generateNullCheck(annotationNode.getTreeMaker(), annotationNode.up()), ast);
if (nullCheck == null) {
// @NonNull applied to a primitive. Kinda pointless. Let's generate a warning.
annotationNode.addWarning("@NonNull is meaningless on a primitive.");
return;
}
List<JCStatement> statements = declaration.body.stats;
String expectedName = annotationNode.up().getName();
for (JCStatement stat : statements) {
if (JavacHandlerUtil.isConstructorCall(stat)) continue;
String varNameOfNullCheck = returnVarNameIfNullCheck(stat);
if (varNameOfNullCheck == null) break;
if (varNameOfNullCheck.equals(expectedName)) return;
}
List<JCStatement> tail = statements;
List<JCStatement> head = List.nil();
for (JCStatement stat : statements) {
if (JavacHandlerUtil.isConstructorCall(stat) || JavacHandlerUtil.isGenerated(stat)) {
tail = tail.tail;
head = head.prepend(stat);
continue;
}
break;
}
List<JCStatement> newList = tail.prepend(nullCheck);
for (JCStatement stat : head) newList = newList.prepend(stat);
declaration.body.stats = newList;
}
/**
* Checks if the statement is of the form 'if (x == null) {throw WHATEVER;},
* where the block braces are optional. If it is of this form, returns "x".
* If it is not of this form, returns null.
*/
private String returnVarNameIfNullCheck(JCStatement stat) {
if (!(stat instanceof JCIf)) return null;
/* Check that the if's statement is a throw statement, possibly in a block. */ {
JCStatement then = ((JCIf) stat).thenpart;
if (then instanceof JCBlock) {
List<JCStatement> stats = ((JCBlock) then).stats;
if (stats.length() == 0) return null;
then = stats.get(0);
}
if (!(then instanceof JCThrow)) return null;
}
/* Check that the if's conditional is like 'x == null'. Return from this method (don't generate
a nullcheck) if 'x' is equal to our own variable's name: There's already a nullcheck here. */ {
JCExpression cond = ((JCIf) stat).cond;
while (cond instanceof JCParens) cond = ((JCParens) cond).expr;
if (!(cond instanceof JCBinary)) return null;
JCBinary bin = (JCBinary) cond;
if (compareCTC(getTag(bin), CTC_EQUAL)) return null;
if (!(bin.lhs instanceof JCIdent)) return null;
if (!(bin.rhs instanceof JCLiteral)) return null;
if (compareCTC(getTypeTag((JCLiteral) bin.rhs), CTC_BOT)) return null;
return ((JCIdent) bin.lhs).name.toString();
}
}
}
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