com.facebook.buck.util.Paths.java Source code

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Here is the source code for com.facebook.buck.util.Paths.java

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/*
 * Copyright 2012-present Facebook, Inc.
 *
 * 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.facebook.buck.util;

import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.Iterables;

import java.io.File;

import javax.annotation.Nullable;

public class Paths {

    private Paths() {
    }

    /**
     * @param from must always refer to a directory (it should either be the empty string or end with
     *     a slash).
     * @param to may refer to either a file or a directory
     */
    public static String computeRelativePath(String from, String to) {
        Preconditions.checkNotNull(from);
        Preconditions.checkArgument(from.isEmpty() || from.endsWith("/"),
                "Directory path must either be the empty string or end with a slash");
        Preconditions.checkNotNull(to);

        if (from.isEmpty()) {
            return to;
        }

        // Both from and to have the same string prefix through this character index.
        int samePrefixIndex = 0;
        while (true) {
            int slashIndex = from.indexOf('/', samePrefixIndex);
            if (slashIndex < 0) {
                break;
            }

            int indexIncludingSlash = slashIndex + 1;
            if (indexIncludingSlash > to.length()) {
                break;
            }

            String fromPathElement = from.substring(samePrefixIndex, indexIncludingSlash);
            String toPathElement = to.substring(samePrefixIndex, indexIncludingSlash);
            if (fromPathElement.equals(toPathElement)) {
                samePrefixIndex = indexIncludingSlash;
            } else {
                break;
            }
        }

        int directoryDepth = 0;
        for (int charIndex = samePrefixIndex + 1; charIndex < from.length(); charIndex++) {
            if (from.charAt(charIndex) == '/') {
                directoryDepth++;
            }
        }

        return Strings.repeat("../", directoryDepth) + to.substring(samePrefixIndex);
    }

    /**
     * @return the path to the parent
     */
    public static String getParentPath(String pathToFile) {
        Preconditions.checkNotNull(pathToFile);
        Preconditions.checkArgument(!pathToFile.isEmpty(), "path cannot be the empty string");

        if (pathToFile.endsWith("/")) {
            pathToFile = pathToFile.substring(0, pathToFile.length() - 1);
        }

        int lastSlashIndex = pathToFile.lastIndexOf('/');
        if (lastSlashIndex < 0) {
            return "";
        } else {
            return pathToFile.substring(0, lastSlashIndex + 1);
        }
    }

    /**
     * Mimic the UNIX command basename.
     * @param path Filesystem path
     * @param suffix Optional suffix (use null to exclude) that will be stripped from the basename if
     *     it is found.
     * @return The file's name, with suffix removed if provided.
     */
    public static String getBasename(String path, @Nullable String suffix) {
        Preconditions.checkNotNull(path);

        String name = new File(path).getName();
        if (suffix != null && name.endsWith(suffix)) {
            return name.substring(0, name.length() - suffix.length());
        } else {
            return name;
        }
    }

    public static Iterable<File> transformPathToFile(Iterable<String> paths) {
        return Iterables.transform(paths, Functions.PATH_TO_FILE);
    }

    public static Iterable<String> transformFileToAbsolutePath(Iterable<File> files) {
        return Iterables.transform(files, Functions.FILE_TO_ABSOLUTE_PATH);
    }

    /**
     * Returns normalized path. On Windows \ will be replaced with /.
     * @return Normalized path
     */
    public static String normalizePathSeparator(String path) {
        return path.replace("\\", "/");
    }

    /** @return true if the specified path contains a backslash character. */
    public static boolean containsBackslash(String path) {
        return path.indexOf('\\') >= 0;
    }
}