The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 "use strict";

 module.metadata = {

   "stability": "experimental"

 };

 const {Cc,Ci,Cr} = require("chrome");

 const byteStreams = require("./byte-streams");

 const textStreams = require("./text-streams");

 // Flags passed when opening a file.  See nsprpub/pr/include/prio.h.

 const OPEN_FLAGS = {

   RDONLY: parseInt("0x01"),

   WRONLY: parseInt("0x02"),

   CREATE_FILE: parseInt("0x08"),

   APPEND: parseInt("0x10"),

   TRUNCATE: parseInt("0x20"),

   EXCL: parseInt("0x80")

 };

 var dirsvc = Cc["@mozilla.org/file/directory_service;1"]

              .getService(Ci.nsIProperties);

 function MozFile(path) {

   var file = Cc['@mozilla.org/file/local;1']

              .createInstance(Ci.nsILocalFile);

   file.initWithPath(path);

   return file;

 }

 function ensureReadable(file) {

   if (!file.isReadable())

     throw new Error("path is not readable: " + file.path);

 }

 function ensureDir(file) {

   ensureExists(file);

   if (!file.isDirectory())

     throw new Error("path is not a directory: " + file.path);

 }

 function ensureFile(file) {

   ensureExists(file);

   if (!file.isFile())

     throw new Error("path is not a file: " + file.path);

 }

 function ensureExists(file) {

   if (!file.exists())

     throw friendlyError(Cr.NS_ERROR_FILE_NOT_FOUND, file.path);

 }

 function friendlyError(errOrResult, filename) {

   var isResult = typeof(errOrResult) === "number";

   var result = isResult ? errOrResult : errOrResult.result;

   switch (result) {

   case Cr.NS_ERROR_FILE_NOT_FOUND:

     return new Error("path does not exist: " + filename);

   }

   return isResult ? new Error("XPCOM error code: " + errOrResult) : errOrResult;

 }

 exports.exists = function exists(filename) {

   return MozFile(filename).exists();

 };

 exports.isFile = function isFile(filename) {

   return MozFile(filename).isFile();

 };

 exports.read = function read(filename, mode) {

   if (typeof(mode) !== "string")

     mode = "";

   // Ensure mode is read-only.

   mode = /b/.test(mode) ? "b" : "";

   var stream = exports.open(filename, mode);

   try {

     var str = stream.read();

   }

   finally {

     stream.close();

   }

   return str;

 };

 exports.join = function join(base) {

   if (arguments.length < 2)

     throw new Error("need at least 2 args");

   base = MozFile(base);

   for (var i = 1; i < arguments.length; i++)

     base.append(arguments[i]);

   return base.path;

 };

 exports.dirname = function dirname(path) {

   var parent = MozFile(path).parent;

   return parent ? parent.path : "";

 };

 exports.basename = function basename(path) {

   var leafName = MozFile(path).leafName;

   // On Windows, leafName when the path is a volume letter and colon ("c:") is

   // the path itself.  But such a path has no basename, so we want the empty

   // string.

   return leafName == path ? "" : leafName;

 };

 exports.list = function list(path) {

   var file = MozFile(path);

   ensureDir(file);

   ensureReadable(file);

   var entries = file.directoryEntries;

   var entryNames = [];

   while(entries.hasMoreElements()) {

     var entry = entries.getNext();

     entry.QueryInterface(Ci.nsIFile);

     entryNames.push(entry.leafName);

   }

   return entryNames;

 };

 exports.open = function open(filename, mode) {

   var file = MozFile(filename);

   if (typeof(mode) !== "string")

     mode = "";

   // File opened for write only.

   if (/w/.test(mode)) {

     if (file.exists())

       ensureFile(file);

     var stream = Cc['@mozilla.org/network/file-output-stream;1'].

                  createInstance(Ci.nsIFileOutputStream);

     var openFlags = OPEN_FLAGS.WRONLY |

                     OPEN_FLAGS.CREATE_FILE |

                     OPEN_FLAGS.TRUNCATE;

     var permFlags = parseInt("0644", 8); // u+rw go+r

     try {

       stream.init(file, openFlags, permFlags, 0);

     }

     catch (err) {

       throw friendlyError(err, filename);

     }

     return /b/.test(mode) ?

            new byteStreams.ByteWriter(stream) :

            new textStreams.TextWriter(stream);

   }

   // File opened for read only, the default.

   ensureFile(file);

   stream = Cc['@mozilla.org/network/file-input-stream;1'].

            createInstance(Ci.nsIFileInputStream);

   try {

     stream.init(file, OPEN_FLAGS.RDONLY, 0, 0);

   }

   catch (err) {

     throw friendlyError(err, filename);

   }

   return /b/.test(mode) ?

          new byteStreams.ByteReader(stream) :

          new textStreams.TextReader(stream);

 };

 exports.remove = function remove(path) {

   var file = MozFile(path);

   ensureFile(file);

   file.remove(false);

 };

 exports.mkpath = function mkpath(path) {

   var file = MozFile(path);

   if (!file.exists())

     file.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt("0755", 8)); // u+rwx go+rx

   else if (!file.isDirectory())

     throw new Error("The path already exists and is not a directory: " + path);

 };

 exports.rmdir = function rmdir(path) {

   var file = MozFile(path);

   ensureDir(file);

   try {

     file.remove(false);

   }

   catch (err) {

     // Bug 566950 explains why we're not catching a specific exception here.

     throw new Error("The directory is not empty: " + path);

   }

 };