com.google.cloud.tools.io.FilePermissions Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of appengine-plugins-core Show documentation

A library for client side software that manages App Engine programs.

The newest version!

/*
 * Copyright 2016 Google LLC.
 *
 * 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.cloud.tools.io;

import com.google.common.annotations.Beta;
import com.google.common.base.Preconditions;
import java.nio.file.AccessDeniedException;
import java.nio.file.Files;
import java.nio.file.NotDirectoryException;
import java.nio.file.Path;

/**
 * Non-IDE specific utility methods for working with file systems. We hope to migrate these into
 * Guava. Clients should beware that these methods are not yet stable and may change without notice.
 */
@Beta
public class FilePermissions {

  /**
   * Check whether the current process can create a directory at the specified path. This is useful
   * for providing immediate feedback to an end user that a path they have selected or typed may not
   * be suitable before attempting to create the directory; e.g. in a tooltip.
   *
   * @param path tentative location for directory
   * @throws AccessDeniedException if a directory in the path is not writable
   * @throws NotDirectoryException if a segment of the path is a file
   */
  public static void verifyDirectoryCreatable(Path path)
      throws AccessDeniedException, NotDirectoryException {

    Preconditions.checkNotNull(path, "Null directory path");
    for (Path segment = path; segment != null; segment = segment.getParent()) {
      if (Files.exists(segment)) {
        if (Files.isDirectory(segment)) {
          // Can't create a directory if the bottom most currently existing directory in
          // the path is not writable.
          if (!Files.isWritable(segment)) {
            throw new AccessDeniedException(segment + " is not writable");
          }
        } else {
          // Can't create a directory if a non-directory file already exists with that name
          // somewhere in the path.
          throw new NotDirectoryException(segment + " is a file");
        }
        break;
      }
    }
  }
}