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// 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
use std::ffi::CStr;
use std::os::raw::c_char;
use std::sync::atomic::{AtomicBool, Ordering};
use nserror::{nsresult, NS_ERROR_FAILURE, NS_OK};
use nsstring::{nsACString, nsCStr};
use xpcom::{
interfaces::{nsIPrefBranch, nsISupports},
RefPtr,
};
/// Whether the current value of the localhost testing pref is permitting
/// metric recording (even if upload is disabled).
static RECORDING_ENABLED: AtomicBool = AtomicBool::new(false);
// Partially cargo-culted from https://searchfox.org/mozilla-central/rev/598e50d2c3cd81cd616654f16af811adceb08f9f/security/manager/ssl/cert_storage/src/lib.rs#1192
#[xpcom(implement(nsIObserver), atomic)]
pub(crate) struct UploadPrefObserver {}
#[allow(non_snake_case)]
impl UploadPrefObserver {
pub(crate) fn begin_observing() -> Result<(), nsresult> {
// Ensure we begin with the correct current value of RECORDING_ENABLED.
let recording_enabled = static_prefs::pref!("telemetry.fog.test.localhost_port") < 0;
RECORDING_ENABLED.store(recording_enabled, Ordering::SeqCst);
// SAFETY: Everything here is self-contained.
//
// * We allocate the pref observer, created by the xpcom macro
// * We query the pref service and bail out if it doesn't exist.
// * We create a nsCStr from a static string.
// * We control all input to `AddObserverImpl`
unsafe {
let pref_obs = Self::allocate(InitUploadPrefObserver {});
let pref_branch: RefPtr<nsIPrefBranch> =
xpcom::components::Preferences::service().map_err(|_| NS_ERROR_FAILURE)?;
let pref_nscstr =
&nsCStr::from("datareporting.healthreport.uploadEnabled") as &nsACString;
(*pref_branch)
.AddObserverImpl(pref_nscstr, pref_obs.coerce(), false)
.to_result()?;
let pref_nscstr = &nsCStr::from("telemetry.fog.test.localhost_port") as &nsACString;
(*pref_branch)
.AddObserverImpl(pref_nscstr, pref_obs.coerce(), false)
.to_result()?;
}
Ok(())
}
unsafe fn Observe(
&self,
_subject: *const nsISupports,
topic: *const c_char,
pref_name: *const u16,
) -> nserror::nsresult {
let topic = CStr::from_ptr(topic).to_str().unwrap();
// Conversion utf16 to utf8 is messy.
// We should only ever observe changes to one of the two prefs we want,
// but just to be on the safe side let's assert.
// cargo-culted from https://searchfox.org/mozilla-central/rev/598e50d2c3cd81cd616654f16af811adceb08f9f/security/manager/ssl/cert_storage/src/lib.rs#1606-1612
// (with a little transformation)
let len = (0..).take_while(|&i| *pref_name.offset(i) != 0).count(); // find NUL.
let slice = std::slice::from_raw_parts(pref_name, len);
let pref_name = match String::from_utf16(slice) {
Ok(name) => name,
Err(_) => return NS_ERROR_FAILURE,
};
log::info!("Observed {:?}, {:?}", topic, pref_name);
debug_assert!(topic == "nsPref:changed");
debug_assert!(
pref_name == "datareporting.healthreport.uploadEnabled"
|| pref_name == "telemetry.fog.test.localhost_port"
);
let upload_enabled = static_prefs::pref!("datareporting.healthreport.uploadEnabled");
let recording_enabled = static_prefs::pref!("telemetry.fog.test.localhost_port") < 0;
log::info!(
"New upload_enabled {}, recording_enabled {}",
upload_enabled,
recording_enabled
);
if RECORDING_ENABLED.load(Ordering::SeqCst) && !recording_enabled {
// Whenever the test pref goes from permitting recording to forbidding it,
// ensure Glean is told to wipe the stores.
// This may send a "deletion-request" ping for a client_id that's never sent
// any other pings.
glean::set_upload_enabled(false);
}
RECORDING_ENABLED.store(recording_enabled, Ordering::SeqCst);
glean::set_upload_enabled(upload_enabled || recording_enabled);
NS_OK
}
}