com.google.devtools.skylark.skylint.NativeRecursiveGlobChecker.java Source code

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Here is the source code for com.google.devtools.skylark.skylint.NativeRecursiveGlobChecker.java

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// Copyright 2017 The Bazel Authors. All rights reserved.
//
// 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.devtools.skylark.skylint;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.syntax.Argument;
import com.google.devtools.build.lib.syntax.AssignmentStatement;
import com.google.devtools.build.lib.syntax.BuildFileAST;
import com.google.devtools.build.lib.syntax.Expression;
import com.google.devtools.build.lib.syntax.FuncallExpression;
import com.google.devtools.build.lib.syntax.Identifier;
import com.google.devtools.build.lib.syntax.ListLiteral;
import com.google.devtools.build.lib.syntax.StringLiteral;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Checks the adherence to Skylark best practices for recursive globs.
 *
 * <p>Recursive globs should be used sparingly and not for files containing source code. This check
 * flags incorrect usage of recurisive globs, for languages known to be problematic.
 */
public class NativeRecursiveGlobChecker extends AstVisitorWithNameResolution {

    /* List of instances of glob(**) we found. */
    private final List<Issue> issues = new ArrayList<>();

    /* List of known variables we've encountered for finding indirect use of glob(**) */
    private final Map<Identifier, Expression> vars = new HashMap<>();

    /* List of variables that were found in globs, but had not yet been resolved in SkyLark
     * processing.  Example:
     *
     * native.glob([my_var])
     *
     * ...
     *
     * my_var = "**\/*.java"
     */
    private final Set<Identifier> waitingFor = new HashSet<>();

    private static final String BAD_RECURSIVE_GLOB = "bad-recursive-glob";

    public static List<Issue> check(BuildFileAST ast) {
        NativeRecursiveGlobChecker checker = new NativeRecursiveGlobChecker();
        checker.visit(ast);
        return checker.issues;
    }

    private void evaluateInclude(Expression exp) {
        if (exp.kind() == Expression.Kind.STRING_LITERAL) {
            StringLiteral str = (StringLiteral) exp;
            String value = str.getValue();
            if (value.contains("**") && value.endsWith("*.java")) {
                issues.add(Issue.create(BAD_RECURSIVE_GLOB,
                        "go/build-style#globs "
                                + "Do not use recursive globs for Java source files. glob() on multiple "
                                + "directories is error prone and can cause serious maintenance problems for "
                                + "BUILD files.",
                        exp.getLocation()));
            }
        } else if (exp.kind() == Expression.Kind.IDENTIFIER) {
            Identifier id = (Identifier) exp;
            if (vars.containsKey(id)) {
                evaluateInclude(vars.get(id));
            } else {
                waitingFor.add(id);
            }
        }
    }

    @Override
    public void visit(FuncallExpression node) {
        if (node.getFunction().toString().equals("glob")) {
            Argument.Passed include = null;
            int index = 0;
            List<Argument.Passed> args = node.getArguments();
            for (Argument.Passed a : args) {
                if (index == 0 && a.isPositional()) {
                    include = a;
                    break;
                } else if (index > 1 && a.isKeyword() && (a.getName() != null && a.getName().equals("include"))) {
                    include = a;
                    break;
                }
                index++;
            }
            if (include != null && include.getValue().kind() == Expression.Kind.LIST_LITERAL) {
                ListLiteral list = (ListLiteral) include.getValue();
                for (Expression exp : list.getElements()) {
                    evaluateInclude(exp);
                }
            }
        }
        super.visit(node);
    }

    @Override
    public void visit(AssignmentStatement node) {
        super.visit(node);
        ImmutableSet<Identifier> lvalues = node.getLValue().boundIdentifiers();
        if (lvalues.size() != 1) {
            return;
        }
        Identifier ident = Iterables.getOnlyElement(lvalues);
        vars.put(ident, node.getExpression());

        if (waitingFor.contains(ident)) {
            evaluateInclude(node.getExpression());
        }
    }
}