gecko-dev/toolkit/modules/FileUtils.jsm
Paolo Amadini ba9c155837 Bug 1391576 - Stop doing main-thread I/O in FileUtils.getFile for the most common case. r=kmag
MozReview-Commit-ID: HybmKdeReeX

--HG--
extra : rebase_source : 1f109e213db36797105471236b8389acc28b1478
2017-08-18 11:12:34 +01:00

176 lines
5.9 KiB
JavaScript

/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* 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/. */
this.EXPORTED_SYMBOLS = [ "FileUtils" ];
Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
const Cc = Components.classes;
const Ci = Components.interfaces;
const Cr = Components.results;
XPCOMUtils.defineLazyServiceGetter(this, "gDirService",
"@mozilla.org/file/directory_service;1",
"nsIProperties");
this.FileUtils = {
MODE_RDONLY: 0x01,
MODE_WRONLY: 0x02,
MODE_RDWR: 0x04,
MODE_CREATE: 0x08,
MODE_APPEND: 0x10,
MODE_TRUNCATE: 0x20,
PERMS_FILE: 0o644,
PERMS_DIRECTORY: 0o755,
/**
* Gets a file at the specified hierarchy under a nsIDirectoryService key.
* @param key
* The Directory Service Key to start from
* @param pathArray
* An array of path components to locate beneath the directory
* specified by |key|. The last item in this array must be the
* leaf name of a file.
* @return nsIFile object for the file specified. The file is NOT created
* if it does not exist, however all required directories along
* the way are if pathArray has more than one item.
*/
getFile: function FileUtils_getFile(key, pathArray, followLinks) {
var file = this.getDir(key, pathArray.slice(0, -1), pathArray.length > 1,
followLinks);
file.append(pathArray[pathArray.length - 1]);
return file;
},
/**
* Gets a directory at the specified hierarchy under a nsIDirectoryService
* key.
* @param key
* The Directory Service Key to start from
* @param pathArray
* An array of path components to locate beneath the directory
* specified by |key|
* @param shouldCreate
* true if the directory hierarchy specified in |pathArray|
* should be created if it does not exist, false otherwise.
* @param followLinks (optional)
* true if links should be followed, false otherwise.
* @return nsIFile object for the location specified.
*/
getDir: function FileUtils_getDir(key, pathArray, shouldCreate, followLinks) {
var dir = gDirService.get(key, Ci.nsIFile);
for (var i = 0; i < pathArray.length; ++i) {
dir.append(pathArray[i]);
}
if (shouldCreate) {
try {
dir.create(Ci.nsIFile.DIRECTORY_TYPE, this.PERMS_DIRECTORY);
} catch (ex) {
if (ex.result != Cr.NS_ERROR_FILE_ALREADY_EXISTS) {
throw ex;
}
// Ignore the exception due to a directory that already exists.
}
}
if (!followLinks)
dir.followLinks = false;
return dir;
},
/**
* Opens a file output stream for writing.
* @param file
* The file to write to.
* @param modeFlags
* (optional) File open flags. Can be undefined.
* @returns nsIFileOutputStream to write to.
* @note The stream is initialized with the DEFER_OPEN behavior flag.
* See nsIFileOutputStream.
*/
openFileOutputStream: function FileUtils_openFileOutputStream(file, modeFlags) {
var fos = Cc["@mozilla.org/network/file-output-stream;1"].
createInstance(Ci.nsIFileOutputStream);
return this._initFileOutputStream(fos, file, modeFlags);
},
/**
* Opens an atomic file output stream for writing.
* @param file
* The file to write to.
* @param modeFlags
* (optional) File open flags. Can be undefined.
* @returns nsIFileOutputStream to write to.
* @note The stream is initialized with the DEFER_OPEN behavior flag.
* See nsIFileOutputStream.
* OpeanAtomicFileOutputStream is generally better than openSafeFileOutputStream
* baecause flushing is not needed in most of the issues.
*/
openAtomicFileOutputStream: function FileUtils_openAtomicFileOutputStream(file, modeFlags) {
var fos = Cc["@mozilla.org/network/atomic-file-output-stream;1"].
createInstance(Ci.nsIFileOutputStream);
return this._initFileOutputStream(fos, file, modeFlags);
},
/**
* Opens a safe file output stream for writing.
* @param file
* The file to write to.
* @param modeFlags
* (optional) File open flags. Can be undefined.
* @returns nsIFileOutputStream to write to.
* @note The stream is initialized with the DEFER_OPEN behavior flag.
* See nsIFileOutputStream.
*/
openSafeFileOutputStream: function FileUtils_openSafeFileOutputStream(file, modeFlags) {
var fos = Cc["@mozilla.org/network/safe-file-output-stream;1"].
createInstance(Ci.nsIFileOutputStream);
return this._initFileOutputStream(fos, file, modeFlags);
},
_initFileOutputStream: function FileUtils__initFileOutputStream(fos, file, modeFlags) {
if (modeFlags === undefined)
modeFlags = this.MODE_WRONLY | this.MODE_CREATE | this.MODE_TRUNCATE;
fos.init(file, modeFlags, this.PERMS_FILE, fos.DEFER_OPEN);
return fos;
},
/**
* Closes an atomic file output stream.
* @param stream
* The stream to close.
*/
closeAtomicFileOutputStream: function FileUtils_closeAtomicFileOutputStream(stream) {
if (stream instanceof Ci.nsISafeOutputStream) {
try {
stream.finish();
return;
} catch (e) {
}
}
stream.close();
},
/**
* Closes a safe file output stream.
* @param stream
* The stream to close.
*/
closeSafeFileOutputStream: function FileUtils_closeSafeFileOutputStream(stream) {
if (stream instanceof Ci.nsISafeOutputStream) {
try {
stream.finish();
return;
} catch (e) {
}
}
stream.close();
},
File: Components.Constructor("@mozilla.org/file/local;1", Ci.nsIFile, "initWithPath")
};