NS_ERROR_FAILURE: Mozilla sdk with firefox mobile (nightlies ok)

Question

I am trying to develop a Firefox extension for the android mobile version of Firefox. My code contains the following snippet:

var target = Cc["@mozilla.org/file/directory_service;1"]
             .getService(Ci.nsIProperties)
             .get("DfltDwnld", Ci.nsIFile);

This works perfectly on the current Firefox on Windows, the Nightlies on Android but not on the current Firefox version on Android. The latter gives the following error:

I/stdout  (17182): ************************************************************
I/stdout  (17182): * Call to xpconnect wrapped JSObject produced this error:  *
I/stdout  (17182): [Exception... "Component returned failure code: 0x80004005 (N
S_ERROR_FAILURE) [nsIProperties.get]"  nsresult: "0x80004005 (NS_ERROR_FAILURE)"
  location: "JS frame :: resource://gre/modules/XPIProvider.jsm -> jar:file:///m
nt/sdcard/jetpack-profile/extensions/jid1-deaye7pPKgPbLg@jetpack.xpi!/bootstrap.
js -> resource://gre/modules/commonjs/toolkit/loader.js -> resource://jid1-deaye
7ppkgpblg-at-jetpack/my-addon/lib/main.js :: extractFile :: line 109"  data: no]

I/stdout  (17182): ************************************************************

Similarly, when I try a different was to create the file, I get a similar results:

Code:

Cu.import("resource://gre/modules/FileUtils.jsm");
var target = FileUtils.getFile("DfltDwnld", entryName);

Result:

E/GeckoConsole( 2157): [JavaScript Error: "[Exception... "Component returned fai
lure code: 0x80004005 (NS_ERROR_FAILURE) [nsIProperties.get]"  nsresult: "0x8000
4005 (NS_ERROR_FAILURE)"  location: "JS frame :: resource://gre/modules/FileUtil
s.jsm :: FileUtils_getDir :: line 63"  data: no]" {file: "resource://gre/modules
/FileUtils.jsm" line: 63}]

Any idea what is going on and what I can do? It is as if the script did not have permission to write to the download directory.

Answer 1

DfltDwnld is left out of Fennec's directory provider.

Still, you can get the default directory with the following line

var dDD = Cc["@mozilla.org/download-manager;1"].getService(Ci.nsIDownloadManager).defaultDownloadsDirectory;