1 files changed, 148 insertions, 0 deletions
diff --git a/toolkit/modules/FileUtils.sys.mjs b/toolkit/modules/FileUtils.sys.mjs
new file mode 100644
index 0000000000..bea38e3161
--- /dev/null
+++ b/toolkit/modules/FileUtils.sys.mjs
@@ -0,0 +1,148 @@
+/* -*- 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/. */
+
+export var 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 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|
+   * @return  nsIFile object for the location specified.
+   */
+  getDir: function FileUtils_getDir(key, pathArray) {
+    var dir = Services.dirsvc.get(key, Ci.nsIFile);
+    for (var i = 0; i < pathArray.length; ++i) {
+      dir.append(pathArray[i]);
+    }
+    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"
+  ),
+};