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90 lines
4.0 KiB
JavaScript
90 lines
4.0 KiB
JavaScript
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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this.EXPORTED_SYMBOLS = [
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"DownloadPaths",
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];
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/**
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* This module provides the DownloadPaths object which contains methods for
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* giving names and paths to files being downloaded.
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*
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* List of methods:
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*
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* nsILocalFile
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* createNiceUniqueFile(nsILocalFile aLocalFile)
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*
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* [string base, string ext]
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* splitBaseNameAndExtension(string aLeafName)
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*/
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const Cc = Components.classes;
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const Ci = Components.interfaces;
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const Cu = Components.utils;
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const Cr = Components.results;
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this.DownloadPaths = {
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/**
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* Creates a uniquely-named file starting from the name of the provided file.
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* If a file with the provided name already exists, the function attempts to
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* create nice alternatives, like "base(1).ext" (instead of "base-1.ext").
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*
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* If a unique name cannot be found, the function throws the XPCOM exception
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* NS_ERROR_FILE_TOO_BIG. Other exceptions, like NS_ERROR_FILE_ACCESS_DENIED,
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* can also be expected.
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*
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* @param aTemplateFile
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* nsILocalFile whose leaf name is going to be used as a template. The
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* provided object is not modified.
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* @returns A new instance of an nsILocalFile object pointing to the newly
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* created empty file. On platforms that support permission bits, the
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* file is created with permissions 600.
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*/
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createNiceUniqueFile: function DP_createNiceUniqueFile(aTemplateFile) {
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// Work on a clone of the provided template file object.
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var curFile = aTemplateFile.clone().QueryInterface(Ci.nsILocalFile);
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var [base, ext] = DownloadPaths.splitBaseNameAndExtension(curFile.leafName);
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// Try other file names, for example "base(1).txt" or "base(1).tar.gz",
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// only if the file name initially set already exists.
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for (let i = 1; i < 10000 && curFile.exists(); i++) {
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curFile.leafName = base + "(" + i + ")" + ext;
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}
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// At this point we hand off control to createUnique, which will create the
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// file with the name we chose, if it is valid. If not, createUnique will
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// attempt to modify it again, for example it will shorten very long names
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// that can't be created on some platforms, and for which a normal call to
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// nsIFile.create would result in NS_ERROR_FILE_NOT_FOUND. This can result
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// very rarely in strange names like "base(9999).tar-1.gz" or "ba-1.gz".
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curFile.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0600);
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return curFile;
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},
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/**
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* Separates the base name from the extension in a file name, recognizing some
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* double extensions like ".tar.gz".
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*
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* @param aLeafName
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* The full leaf name to be parsed. Be careful when processing names
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* containing leading or trailing dots or spaces.
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* @returns [base, ext]
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* The base name of the file, which can be empty, and its extension,
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* which always includes the leading dot unless it's an empty string.
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* Concatenating the two items always results in the original name.
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*/
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splitBaseNameAndExtension: function DP_splitBaseNameAndExtension(aLeafName) {
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// The following regular expression is built from these key parts:
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// .*? Matches the base name non-greedily.
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// \.[A-Z0-9]{1,3} Up to three letters or numbers preceding a
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// double extension.
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// \.(?:gz|bz2|Z) The second part of common double extensions.
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// \.[^.]* Matches any extension or a single trailing dot.
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var [, base, ext] = /(.*?)(\.[A-Z0-9]{1,3}\.(?:gz|bz2|Z)|\.[^.]*)?$/i
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.exec(aLeafName);
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// Return an empty string instead of undefined if no extension is found.
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return [base, ext || ""];
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}
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};
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