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

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Here is the source code for com.google.errorprone.bugpatterns.ParameterName.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.collect.Iterables.getLast;
import static com.google.common.collect.Streams.forEachPair;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.sun.tools.javac.parser.Tokens.Comment.CommentStyle.BLOCK;

import com.google.common.collect.Range;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.ProvidesFix;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.bugpatterns.BugChecker.NewClassTreeMatcher;
import com.google.errorprone.bugpatterns.argumentselectiondefects.NamedParameterComment;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.google.errorprone.util.Comments;
import com.google.errorprone.util.ErrorProneToken;
import com.google.errorprone.util.ErrorProneTokens;
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.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Symbol.VarSymbol;
import com.sun.tools.javac.parser.Tokens.Comment;
import com.sun.tools.javac.tree.JCTree;
import com.sun.tools.javac.util.Position;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.regex.Matcher;

/** @author cushon@google.com (Liam Miller-Cushon) */
@BugPattern(name = "ParameterName", summary = "Detects `/* name= */`-style comments on actual parameters where the name doesn't match the"
        + " formal parameter", severity = WARNING, providesFix = ProvidesFix.REQUIRES_HUMAN_ATTENTION)
public class ParameterName extends BugChecker implements MethodInvocationTreeMatcher, NewClassTreeMatcher {

    @Override
    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
        checkArguments(tree, tree.getArguments(), state);
        return NO_MATCH;
    }

    @Override
    public Description matchNewClass(NewClassTree tree, VisitorState state) {
        checkArguments(tree, tree.getArguments(), state);
        return NO_MATCH;
    }

    private void checkArguments(Tree tree, List<? extends ExpressionTree> arguments, VisitorState state) {
        if (arguments.isEmpty()) {
            return;
        }
        MethodSymbol sym = (MethodSymbol) ASTHelpers.getSymbol(tree);
        if (NamedParameterComment.containsSyntheticParameterName(sym)) {
            return;
        }
        int start = ((JCTree) tree).getStartPosition();
        int end = state.getEndPosition(getLast(arguments));
        if (start == Position.NOPOS || end == Position.NOPOS) {
            // best effort work-around for https://github.com/google/error-prone/issues/780
            return;
        }
        String source = state.getSourceCode().subSequence(start, end).toString();
        if (!source.contains("/*")) {
            // fast path if the arguments don't contain anything that looks like a comment
            return;
        }
        Deque<ErrorProneToken> tokens = new ArrayDeque<>(ErrorProneTokens.getTokens(source, state.context));
        forEachPair(sym.getParameters().stream(), arguments.stream(), (p, a) -> {
            while (!tokens.isEmpty() && ((start + tokens.peekFirst().pos()) < ((JCTree) a).getStartPosition())) {
                tokens.removeFirst();
            }
            if (tokens.isEmpty()) {
                return;
            }
            Range<Integer> argRange = Range.closedOpen(((JCTree) a).getStartPosition(), state.getEndPosition(a));
            if (!argRange.contains(start + tokens.peekFirst().pos())) {
                return;
            }
            checkArgument(p, a, start, tokens.removeFirst(), state);
        });
    }

    private void checkArgument(VarSymbol formal, ExpressionTree actual, int start, ErrorProneToken token,
            VisitorState state) {
        List<Comment> matches = new ArrayList<>();
        for (Comment comment : token.comments()) {
            if (comment.getStyle() != BLOCK) {
                continue;
            }
            Matcher m = NamedParameterComment.PARAMETER_COMMENT_PATTERN
                    .matcher(Comments.getTextFromComment(comment));
            if (!m.matches()) {
                continue;
            }
            String name = m.group(1);
            if (formal.getSimpleName().contentEquals(name)) {
                // If there are multiple comments, bail if any one of them is an exact match.
                return;
            }
            matches.add(comment);
        }
        for (Comment match : matches) {
            state.reportMatch(buildDescription(actual)
                    .setMessage(String.format("`%s` does not match formal parameter name `%s`", match.getText(),
                            formal.getSimpleName()))
                    .addFix(SuggestedFix.replace(start + match.getSourcePos(0),
                            start + match.getSourcePos(match.getText().length() - 1) + 1,
                            String.format("/* %s= */", formal.getSimpleName())))
                    .build());
        }
    }
}