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/toolkit/mozapps/downloads/DownloadPaths.jsm

http://github.com/zpao/v8monkey
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  1/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  2/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
  3/* ***** BEGIN LICENSE BLOCK *****
  4 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  5 *
  6 * The contents of this file are subject to the Mozilla Public License Version
  7 * 1.1 (the "License"); you may not use this file except in compliance with
  8 * the License. You may obtain a copy of the License at
  9 * http://www.mozilla.org/MPL/
 10 *
 11 * Software distributed under the License is distributed on an "AS IS" basis,
 12 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 13 * for the specific language governing rights and limitations under the
 14 * License.
 15 *
 16 * The Original Code is Download Manager Utility Code.
 17 *
 18 * The Initial Developer of the Original Code is
 19 * Paolo Amadini <http://www.amadzone.org/>.
 20 * Portions created by the Initial Developer are Copyright (C) 2010
 21 * the Initial Developer. All Rights Reserved.
 22 *
 23 * Contributor(s):
 24 *
 25 * Alternatively, the contents of this file may be used under the terms of
 26 * either the GNU General Public License Version 2 or later (the "GPL"), or
 27 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 28 * in which case the provisions of the GPL or the LGPL are applicable instead
 29 * of those above. If you wish to allow use of your version of this file only
 30 * under the terms of either the GPL or the LGPL, and not to allow others to
 31 * use your version of this file under the terms of the MPL, indicate your
 32 * decision by deleting the provisions above and replace them with the notice
 33 * and other provisions required by the GPL or the LGPL. If you do not delete
 34 * the provisions above, a recipient may use your version of this file under
 35 * the terms of any one of the MPL, the GPL or the LGPL.
 36 *
 37 * ***** END LICENSE BLOCK ***** */
 38
 39var EXPORTED_SYMBOLS = [
 40  "DownloadPaths",
 41];
 42
 43/**
 44 * This module provides the DownloadPaths object which contains methods for
 45 * giving names and paths to files being downloaded.
 46 *
 47 * List of methods:
 48 *
 49 * nsILocalFile
 50 * createNiceUniqueFile(nsILocalFile aLocalFile)
 51 *
 52 * [string base, string ext]
 53 * splitBaseNameAndExtension(string aLeafName)
 54 */
 55
 56const Cc = Components.classes;
 57const Ci = Components.interfaces;
 58const Cu = Components.utils;
 59const Cr = Components.results;
 60
 61const DownloadPaths = {
 62  /**
 63   * Creates a uniquely-named file starting from the name of the provided file.
 64   * If a file with the provided name already exists, the function attempts to
 65   * create nice alternatives, like "base(1).ext" (instead of "base-1.ext").
 66   *
 67   * If a unique name cannot be found, the function throws the XPCOM exception
 68   * NS_ERROR_FILE_TOO_BIG. Other exceptions, like NS_ERROR_FILE_ACCESS_DENIED,
 69   * can also be expected.
 70   *
 71   * @param aTemplateFile
 72   *        nsILocalFile whose leaf name is going to be used as a template. The
 73   *        provided object is not modified.
 74   * @returns A new instance of an nsILocalFile object pointing to the newly
 75   *          created empty file. On platforms that support permission bits, the
 76   *          file is created with permissions 600.
 77   */
 78  createNiceUniqueFile: function DP_createNiceUniqueFile(aTemplateFile) {
 79    // Work on a clone of the provided template file object.
 80    var curFile = aTemplateFile.clone().QueryInterface(Ci.nsILocalFile);
 81    var [base, ext] = DownloadPaths.splitBaseNameAndExtension(curFile.leafName);
 82    // Try other file names, for example "base(1).txt" or "base(1).tar.gz",
 83    // only if the file name initially set already exists.
 84    for (let i = 1; i < 10000 && curFile.exists(); i++) {
 85      curFile.leafName = base + "(" + i + ")" + ext;
 86    }
 87    // At this point we hand off control to createUnique, which will create the
 88    // file with the name we chose, if it is valid. If not, createUnique will
 89    // attempt to modify it again, for example it will shorten very long names
 90    // that can't be created on some platforms, and for which a normal call to
 91    // nsIFile.create would result in NS_ERROR_FILE_NOT_FOUND. This can result
 92    // very rarely in strange names like "base(9999).tar-1.gz" or "ba-1.gz".
 93    curFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0600);
 94    return curFile;
 95  },
 96
 97  /**
 98   * Separates the base name from the extension in a file name, recognizing some
 99   *  double extensions like ".tar.gz".
100   *
101   * @param aLeafName
102   *        The full leaf name to be parsed. Be careful when processing names
103   *        containing leading or trailing dots or spaces.
104   * @returns [base, ext]
105   *          The base name of the file, which can be empty, and its extension,
106   *          which always includes the leading dot unless it's an empty string.
107   *          Concatenating the two items always results in the original name.
108   */
109  splitBaseNameAndExtension: function DP_splitBaseNameAndExtension(aLeafName) {
110    // The following regular expression is built from these key parts:
111    //  .*?                      Matches the base name non-greedily.
112    //  \.[A-Z0-9]{1,3}          Up to three letters or numbers preceding a
113    //                           double extension.
114    //  \.(?:gz|bz2|Z)           The second part of common double extensions.
115    //  \.[^.]*                  Matches any extension or a single trailing dot.
116    var [, base, ext] = /(.*?)(\.[A-Z0-9]{1,3}\.(?:gz|bz2|Z)|\.[^.]*)?$/i
117                        .exec(aLeafName);
118    // Return an empty string instead of undefined if no extension is found.
119    return [base, ext || ""];
120  }
121};