com.google.errorprone.bugpatterns.ProvidesFixChecker.java Source code

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Here is the source code for com.google.errorprone.bugpatterns.ProvidesFixChecker.java

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/*
 * Copyright 2017 The Error Prone Authors.
 *
 * 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.errorprone.bugpatterns;

import static com.google.common.base.MoreObjects.firstNonNull;
import static com.google.errorprone.BugPattern.ProvidesFix.NO_FIX;
import static com.google.errorprone.BugPattern.ProvidesFix.REQUIRES_HUMAN_ATTENTION;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.Matchers.anyOf;
import static com.google.errorprone.util.ASTHelpers.getSymbol;

import com.google.common.collect.Iterables;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.AnnotationMatcherUtils;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.matchers.method.MethodMatchers;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.TreeScanner;

@BugPattern(name = "ProvidesFix", summary = "BugChecker has incorrect ProvidesFix tag, please update", severity = WARNING, providesFix = REQUIRES_HUMAN_ATTENTION)
public class ProvidesFixChecker extends BugChecker implements ClassTreeMatcher {

    private static final Matcher<ClassTree> IS_BUGCHECKER = Matchers
            .isSubtypeOf("com.google.errorprone.bugpatterns.BugChecker");
    private static final Matcher<MethodInvocationTree> DESCRIPTION_WITH_FIX = anyOf(
            MethodMatchers.instanceMethod().onDescendantOf("com.google.errorprone.matchers.Description.Builder")
                    .namedAnyOf("addFix", "addAllFixes"),
            MethodMatchers.instanceMethod().onDescendantOf("com.google.errorprone.bugpatterns.BugChecker")
                    .named("describeMatch")
                    .withParameters("com.sun.source.tree.Tree", "com.google.errorprone.fixes.Fix"));
    private static final Matcher<ExpressionTree> DESCRIPTION_CONSTRUCTOR = Matchers.constructor()
            .forClass("com.google.errorprone.matchers.Description").withParameters("com.sun.source.tree.Tree",
                    "java.lang.String", "com.google.errorprone.fixes.Fix",
                    "com.google.errorprone.BugPattern.SeverityLevel");

    @Override
    public Description matchClass(ClassTree tree, VisitorState state) {
        if (!IS_BUGCHECKER.matches(tree, state)) {
            return NO_MATCH;
        }

        AnnotationTree bugPatternAnnotation = ASTHelpers
                .getAnnotationWithSimpleName(tree.getModifiers().getAnnotations(), "BugPattern");
        if (bugPatternAnnotation == null) {
            return NO_MATCH;
        }

        if (!providesFix(tree, state)) {
            // N.B. BugCheckers can provide a fix in ways we cannot detect.
            // Ignore checkers that don't appear to have a fix, but are labeled as having one.
            return NO_MATCH;
        }

        SuggestedFix.Builder fixBuilder = SuggestedFix.builder()
                .addImport("com.google.errorprone.BugPattern.ProvidesFix");
        ExpressionTree providesFixArgument = AnnotationMatcherUtils.getArgument(bugPatternAnnotation,
                "providesFix");
        if (providesFixArgument == null) {
            // If providesFix argument not already present, add it to the end of @BugPattern args.
            fixBuilder.postfixWith(Iterables.getLast(bugPatternAnnotation.getArguments()),
                    ", providesFix = ProvidesFix." + REQUIRES_HUMAN_ATTENTION.name());
        } else {
            if (!getSymbol(providesFixArgument).getSimpleName().contentEquals(NO_FIX.name())) {
                // If providesFix arg already states there is a fix, we're good.
                return NO_MATCH;
            }
            // If providesFix arg incorrectly states there is no fix, correct it.
            fixBuilder.replace(providesFixArgument, "ProvidesFix." + REQUIRES_HUMAN_ATTENTION.name());
        }
        return describeMatch(bugPatternAnnotation, fixBuilder.build());
    }

    private static boolean providesFix(Tree tree, VisitorState state) {
        return tree.accept(new TreeScanner<Boolean, Void>() {
            @Override
            public Boolean visitMethodInvocation(MethodInvocationTree callTree, Void unused) {
                return super.visitMethodInvocation(callTree, unused)
                        || DESCRIPTION_WITH_FIX.matches(callTree, state);
            }

            @Override
            public Boolean visitNewClass(NewClassTree constructorTree, Void unused) {
                return super.visitNewClass(constructorTree, unused)
                        || DESCRIPTION_CONSTRUCTOR.matches(constructorTree, state);
            }

            @Override
            public Boolean reduce(Boolean m1, Boolean m2) {
                return firstNonNull(m1, false) || firstNonNull(m2, false);
            }
        }, null);
    }
}