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/*
* Copyright (C) 2013-2021 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.core.handlers.HandlerUtil.handleFlagUsage;
import static lombok.javac.Javac.*;
import static lombok.javac.JavacTreeMaker.TreeTag.treeTag;
import static lombok.javac.JavacTreeMaker.TypeTag.typeTag;
import static lombok.javac.handlers.JavacHandlerUtil.*;
import java.util.ArrayList;
import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.tree.JCTree.JCAnnotation;
import com.sun.tools.javac.tree.JCTree.JCAssert;
import com.sun.tools.javac.tree.JCTree.JCAssign;
import com.sun.tools.javac.tree.JCTree.JCBinary;
import com.sun.tools.javac.tree.JCTree.JCBlock;
import com.sun.tools.javac.tree.JCTree.JCClassDecl;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.tree.JCTree.JCExpressionStatement;
import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
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.JCMethodInvocation;
import com.sun.tools.javac.tree.JCTree.JCModifiers;
import com.sun.tools.javac.tree.JCTree.JCParens;
import com.sun.tools.javac.tree.JCTree.JCStatement;
import com.sun.tools.javac.tree.JCTree.JCSynchronized;
import com.sun.tools.javac.tree.JCTree.JCThrow;
import com.sun.tools.javac.tree.JCTree.JCTry;
import com.sun.tools.javac.tree.JCTree.JCTypeParameter;
import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
import com.sun.tools.javac.util.List;
import com.sun.tools.javac.util.ListBuffer;
import com.sun.tools.javac.util.Name;
import lombok.AccessLevel;
import lombok.ConfigurationKeys;
import lombok.NonNull;
import lombok.core.AST.Kind;
import lombok.core.AnnotationValues;
import lombok.core.HandlerPriority;
import lombok.javac.JavacAnnotationHandler;
import lombok.javac.JavacNode;
import lombok.javac.JavacTreeMaker;
import lombok.spi.Provides;
@Provides
@HandlerPriority(value = 512) // 2^9; onParameter=@__(@NonNull) has to run first.
public class HandleNonNull extends JavacAnnotationHandler {
private JCMethodDecl createRecordArgslessConstructor(JavacNode typeNode, JavacNode source, JCMethodDecl existingCtr) {
JavacTreeMaker maker = typeNode.getTreeMaker();
java.util.List fields = new ArrayList();
for (JavacNode child : typeNode.down()) {
if (child.getKind() == Kind.FIELD) {
JCVariableDecl v = (JCVariableDecl) child.get();
if ((v.mods.flags & RECORD) != 0) {
fields.add(v);
}
}
}
ListBuffer params = new ListBuffer();
for (int i = 0; i < fields.size(); i++) {
JCVariableDecl arg = fields.get(i);
JCModifiers mods = maker.Modifiers(GENERATED_MEMBER | Flags.PARAMETER, arg.mods.annotations);
params.append(maker.VarDef(mods, arg.name, arg.vartype, null));
}
JCModifiers mods = maker.Modifiers(toJavacModifier(AccessLevel.PUBLIC) | COMPACT_RECORD_CONSTRUCTOR, List.nil());
JCBlock body = maker.Block(0L, List.nil());
if (existingCtr == null) {
JCMethodDecl constr = maker.MethodDef(mods, typeNode.toName(""), null, List.nil(), params.toList(), List.nil(), body, null);
return recursiveSetGeneratedBy(constr, source);
} else {
existingCtr.mods = mods;
existingCtr.body = body;
existingCtr = recursiveSetGeneratedBy(existingCtr, source);
addSuppressWarningsAll(existingCtr.mods, typeNode, typeNode.getNodeFor(getGeneratedBy(existingCtr)), typeNode.getContext());
addGenerated(existingCtr.mods, typeNode, typeNode.getNodeFor(getGeneratedBy(existingCtr)), typeNode.getContext());
return existingCtr;
}
}
/**
* If the provided typeNode is a record, returns the compact constructor (there should only be one, but if the file is
* not semantically sound there might be more). If the only one in existence is the default auto-generated one, it is removed,
* a new explicit one is created, and that one is returned in a list.
*
* Otherwise, an empty list is returned.
*/
private List addCompactConstructorIfNeeded(JavacNode typeNode, JavacNode source) {
List answer = List.nil();
if (typeNode == null || !(typeNode.get() instanceof JCClassDecl)) return answer;
JCClassDecl cDecl = (JCClassDecl) typeNode.get();
if ((cDecl.mods.flags & RECORD) == 0) return answer;
boolean generateConstructor = false;
JCMethodDecl existingCtr = null;
for (JCTree def : cDecl.defs) {
if (def instanceof JCMethodDecl) {
JCMethodDecl md = (JCMethodDecl) def;
if (md.name.contentEquals("")) {
if ((md.mods.flags & Flags.GENERATEDCONSTR) != 0) {
existingCtr = md;
existingCtr.mods.flags = existingCtr.mods.flags & ~Flags.GENERATEDCONSTR;
generateConstructor = true;
} else {
if (!isTolerate(typeNode, md)) {
if ((md.mods.flags & COMPACT_RECORD_CONSTRUCTOR) != 0) {
generateConstructor = false;
answer = answer.prepend(md);
}
}
}
}
}
}
if (generateConstructor) {
JCMethodDecl ctr;
if (existingCtr != null) {
ctr = createRecordArgslessConstructor(typeNode, source, existingCtr);
} else {
ctr = createRecordArgslessConstructor(typeNode, source, null);
injectMethod(typeNode, ctr);
}
answer = answer.prepend(ctr);
}
return answer;
}
private void addNullCheckIfNeeded(JCMethodDecl method, JavacNode paramNode, JavacNode source) {
// 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 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(source.getTreeMaker(), paramNode, source), source);
if (nullCheck == null) {
// @NonNull applied to a primitive. Kinda pointless. Let's generate a warning.
source.addWarning("@NonNull is meaningless on a primitive.");
return;
}
List statements = method.body.stats;
String expectedName = paramNode.getName();
/* Abort if the null check is already there, delving into try and synchronized statements */ {
List stats = statements;
int idx = 0;
while (stats.size() > idx) {
JCStatement stat = stats.get(idx++);
if (JavacHandlerUtil.isConstructorCall(stat)) continue;
if (stat instanceof JCTry) {
stats = ((JCTry) stat).body.stats;
idx = 0;
continue;
}
if (stat instanceof JCSynchronized) {
stats = ((JCSynchronized) stat).body.stats;
idx = 0;
continue;
}
String varNameOfNullCheck = returnVarNameIfNullCheck(stat);
if (varNameOfNullCheck == null) break;
if (varNameOfNullCheck.equals(expectedName)) return;
}
}
List tail = statements;
List head = List.nil();
for (JCStatement stat : statements) {
if (JavacHandlerUtil.isConstructorCall(stat) || (JavacHandlerUtil.isGenerated(stat) && isNullCheck(stat))) {
tail = tail.tail;
head = head.prepend(stat);
continue;
}
break;
}
List newList = tail.prepend(nullCheck);
for (JCStatement stat : head) newList = newList.prepend(stat);
method.body.stats = newList;
source.getAst().setChanged();
}
@Override public void handle(AnnotationValues annotation, JCAnnotation ast, JavacNode annotationNode) {
handleFlagUsage(annotationNode, ConfigurationKeys.NON_NULL_FLAG_USAGE, "@NonNull");
final JavacNode node;
if (annotationNode.up().getKind() == Kind.TYPE_USE) {
node = annotationNode.directUp().directUp();
} else {
node = annotationNode.up();
}
if (node.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) node.get()).vartype)) {
annotationNode.addWarning("@NonNull is meaningless on a primitive.");
}
} catch (Exception ignore) {}
JCVariableDecl fDecl = (JCVariableDecl) node.get();
if ((fDecl.mods.flags & RECORD) != 0) {
// well, these kinda double as parameters (of the compact constructor), so we do some work here.
List compactConstructors = addCompactConstructorIfNeeded(node.up(), annotationNode);
for (JCMethodDecl ctr : compactConstructors) {
addNullCheckIfNeeded(ctr, node, annotationNode);
}
}
return;
}
if (node.getKind() != Kind.ARGUMENT) return;
JCMethodDecl declaration;
try {
declaration = (JCMethodDecl) node.up().get();
} catch (Exception e) {
return;
}
if (declaration.body == null) {
// This used to be a warning, but as @NonNull also has a documentary purpose, better to not warn about this. Since 1.16.7
return;
}
if ((declaration.mods.flags & (GENERATED_MEMBER | COMPACT_RECORD_CONSTRUCTOR)) != 0) {
// The 'real' annotations are on the `record Foo(@NonNull Obj x)` part and we just see these
// syntax-sugared over. We deal with it on the field declaration variant, as those are always there,
// not dependent on whether you write out the compact constructor or not.
return;
}
addNullCheckIfNeeded(declaration, node, annotationNode);
}
public boolean isNullCheck(JCStatement stat) {
return returnVarNameIfNullCheck(stat) != null;
}
/**
* Checks if the statement is of the form 'if (x == null) {throw WHATEVER;}' or 'assert x != null;',
* where the block braces are optional. If it is of this form, returns "x".
* If it is not of this form, returns null.
*/
public String returnVarNameIfNullCheck(JCStatement stat) {
boolean isIf = stat instanceof JCIf;
boolean isExpression = stat instanceof JCExpressionStatement;
if (!isIf && !(stat instanceof JCAssert) && !isExpression) return null;
if (isExpression) {
/* Check if the statements contains a call to checkNotNull or requireNonNull */
JCExpression expression = ((JCExpressionStatement) stat).expr;
if (expression instanceof JCAssign) expression = ((JCAssign) expression).rhs;
if (!(expression instanceof JCMethodInvocation)) return null;
JCMethodInvocation invocation = (JCMethodInvocation) expression;
JCExpression method = invocation.meth;
Name name = null;
if (method instanceof JCFieldAccess) {
name = ((JCFieldAccess) method).name;
} else if (method instanceof JCIdent) {
name = ((JCIdent) method).name;
}
if (name == null || (!name.contentEquals("checkNotNull") && !name.contentEquals("requireNonNull"))) return null;
if (invocation.args.isEmpty()) return null;
JCExpression firstArgument = invocation.args.head;
if (!(firstArgument instanceof JCIdent)) return null;
return ((JCIdent) firstArgument).toString();
}
if (isIf) {
/* Check that the if's statement is a throw statement, possibly in a block. */
JCStatement then = ((JCIf) stat).thenpart;
if (then instanceof JCBlock) {
List 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 = isIf ? ((JCIf) stat).cond : ((JCAssert) stat).cond;
while (cond instanceof JCParens) cond = ((JCParens) cond).expr;
if (!(cond instanceof JCBinary)) return null;
JCBinary bin = (JCBinary) cond;
if (isIf) {
if (!CTC_EQUAL.equals(treeTag(bin))) return null;
} else {
if (!CTC_NOT_EQUAL.equals(treeTag(bin))) return null;
}
if (!(bin.lhs instanceof JCIdent)) return null;
if (!(bin.rhs instanceof JCLiteral)) return null;
if (!CTC_BOT.equals(typeTag(bin.rhs))) return null;
return ((JCIdent) bin.lhs).name.toString();
}
}
}