Source code

Revision control

Copy as Markdown

Other Tools

/* 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 */
* Provides methods for giving names and paths to files being downloaded.
export var DownloadPaths = {
* Sanitizes an arbitrary string via mimeSvc.validateFileNameForSaving.
* If the filename being validated is one that was returned from a
* file picker, pass false for compressWhitespaces and true for
* allowInvalidFilenames. Otherwise, the default values of the arguments
* should generally be used.
* @param {string} leafName The full leaf name to sanitize
* @param {boolean} [compressWhitespaces] Whether consecutive whitespaces
* should be compressed. The default value is true.
* @param {boolean} [allowInvalidFilenames] Allow invalid and dangerous
* filenames and extensions as is.
{ compressWhitespaces = true, allowInvalidFilenames = false } = {}
) {
const mimeSvc = Cc[";1"].getService(Ci.nsIMIMEService);
if (!compressWhitespaces) {
if (allowInvalidFilenames) {
return mimeSvc.validateFileNameForSaving(leafName, "", flags);
* Creates a uniquely-named file starting from the name of the provided file.
* If a file with the provided name already exists, the function attempts to
* create nice alternatives, like "base(1).ext" (instead of "base-1.ext").
* If a unique name cannot be found, the function throws the XPCOM exception
* can also be expected.
* @param templateFile
* nsIFile whose leaf name is going to be used as a template. The
* provided object is not modified.
* @return A new instance of an nsIFile object pointing to the newly created
* empty file. On platforms that support permission bits, the file is
* created with permissions 644.
createNiceUniqueFile(templateFile) {
// Work on a clone of the provided template file object.
let curFile = templateFile.clone().QueryInterface(Ci.nsIFile);
let [base, ext] = DownloadPaths.splitBaseNameAndExtension(curFile.leafName);
// Try other file names, for example "base(1).txt" or "base(1).tar.gz",
// only if the file name initially set already exists.
for (let i = 1; i < 10000 && curFile.exists(); i++) {
curFile.leafName = base + "(" + i + ")" + ext;
// At this point we hand off control to createUnique, which will create the
// file with the name we chose, if it is valid. If not, createUnique will
// attempt to modify it again, for example it will shorten very long names
// that can't be created on some platforms, and for which a normal call to
// nsIFile.create would result in NS_ERROR_FILE_NOT_FOUND. This can result
// very rarely in strange names like "base(9999).tar-1.gz" or "ba-1.gz".
curFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o644);
return curFile;
* Separates the base name from the extension in a file name, recognizing some
* double extensions like ".tar.gz".
* @param leafName
* The full leaf name to be parsed. Be careful when processing names
* containing leading or trailing dots or spaces.
* @return [base, ext]
* The base name of the file, which can be empty, and its extension,
* which always includes the leading dot unless it's an empty string.
* Concatenating the two items always results in the original name.
splitBaseNameAndExtension(leafName) {
// The following regular expression is built from these key parts:
// .*? Matches the base name non-greedily.
// \.[A-Z0-9]{1,3} Up to three letters or numbers preceding a
// double extension.
// \.(?:gz|bz2|Z) The second part of common double extensions.
// \.[^.]* Matches any extension or a single trailing dot.
let [, base, ext] = /(.*?)(\.[A-Z0-9]{1,3}\.(?:gz|bz2|Z)|\.[^.]*)?$/i.exec(
// Return an empty string instead of undefined if no extension is found.
return [base, ext || ""];