com.google.gerrit.server.project.RefPattern.java Source code

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Here is the source code for com.google.gerrit.server.project.RefPattern.java

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// Copyright (C) 2016 The Android Open Source Project
//
// 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.gerrit.server.project;

import com.google.common.base.Throwables;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.gerrit.common.data.AccessSection;
import com.google.gerrit.common.data.RefConfigSection;
import com.google.gerrit.common.errors.InvalidNameException;

import dk.brics.automaton.RegExp;

import org.eclipse.jgit.lib.Repository;

import java.util.concurrent.ExecutionException;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

public class RefPattern {
    public static final String USERID_SHARDED = "shardeduserid";
    public static final String USERNAME = "username";

    private static final LoadingCache<String, String> exampleCache = CacheBuilder.newBuilder().maximumSize(4000)
            .build(new CacheLoader<String, String>() {
                @Override
                public String load(String refPattern) {
                    return example(refPattern);
                }
            });

    public static String shortestExample(String refPattern) {
        if (isRE(refPattern)) {
            try {
                return exampleCache.get(refPattern);
            } catch (ExecutionException e) {
                Throwables.propagateIfPossible(e.getCause());
                throw new RuntimeException(e);
            }
        } else if (refPattern.endsWith("/*")) {
            return refPattern.substring(0, refPattern.length() - 1) + '1';
        } else {
            return refPattern;
        }
    }

    static String example(String refPattern) {
        // Since Brics will substitute dot [.] with \0 when generating
        // shortest example, any usage of dot will fail in
        // Repository.isValidRefName() if not combined with star [*].
        // To get around this, we substitute the \0 with an arbitrary
        // accepted character.
        return toRegExp(refPattern).toAutomaton().getShortestExample(true).replace('\0', '-');
    }

    public static boolean isRE(String refPattern) {
        return refPattern.startsWith(AccessSection.REGEX_PREFIX);
    }

    public static RegExp toRegExp(String refPattern) {
        if (isRE(refPattern)) {
            refPattern = refPattern.substring(1);
        }
        return new RegExp(refPattern, RegExp.NONE);
    }

    public static void validate(String refPattern) throws InvalidNameException {
        if (refPattern.startsWith(RefConfigSection.REGEX_PREFIX)) {
            if (!Repository.isValidRefName(shortestExample(refPattern))) {
                throw new InvalidNameException(refPattern);
            }
        } else if (refPattern.equals(RefConfigSection.ALL)) {
            // This is a special case we have to allow, it fails below.
        } else if (refPattern.endsWith("/*")) {
            String prefix = refPattern.substring(0, refPattern.length() - 2);
            if (!Repository.isValidRefName(prefix)) {
                throw new InvalidNameException(refPattern);
            }
        } else if (!Repository.isValidRefName(refPattern)) {
            throw new InvalidNameException(refPattern);
        }
        validateRegExp(refPattern);
    }

    public static void validateRegExp(String refPattern) throws InvalidNameException {
        try {
            refPattern = refPattern.replace("${" + USERID_SHARDED + "}", "");
            refPattern = refPattern.replace("${" + USERNAME + "}", "");
            Pattern.compile(refPattern);
        } catch (PatternSyntaxException e) {
            throw new InvalidNameException(refPattern + " " + e.getMessage());
        }
    }
}