Source code
Revision control
Copy as Markdown
Other Tools
/* 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 super::{
action::{Action, ServiceAction},
error::{
ErrorStage::{MainThread, Pretask},
ErrorType,
ErrorType::{
BitsStateCancelled, FailedToDispatchRunnable, FailedToStartThread, InvalidArgument,
OperationAlreadyInProgress, TransferAlreadyComplete,
},
},
monitor::MonitorRunnable,
task::{
CancelTask, ChangeMonitorIntervalTask, CompleteTask, Priority, ResumeTask,
SetNoProgressTimeoutTask, SetPriorityTask, SuspendTask,
},
BitsService, BitsTaskError,
};
use nsIBitsRequest_method; // From xpcom_method.rs
use bits_client::{BitsMonitorClient, Guid};
use log::{error, info, warn};
use moz_task::create_thread;
use nserror::{nsresult, NS_ERROR_ABORT, NS_ERROR_NOT_IMPLEMENTED, NS_OK};
use nsstring::{nsACString, nsCString};
use std::{cell::Cell, fmt};
use xpcom::{
interfaces::{
nsIBits, nsIBitsCallback, nsILoadGroup, nsIProgressEventSink, nsIRequestObserver,
nsISupports, nsIThread, nsLoadFlags,
},
xpcom, xpcom_method, RefPtr, XpCom,
};
/// This structure exists to resolve a race condition. If cancel is called, we
/// don't want to immediately set the request state to cancelled, because the
/// cancel action could fail. But it's possible that on_stop() could be called
/// before the cancel action resolves, and the correct status should be sent to
/// OnStopRequest.
/// This is how this race condition will be resolved:
/// 1. cancel() is called, which sets the CancelAction to InProgress and
/// stores in it the status that should be set if it succeeds.
/// 2. cancel() dispatches the cancel task off thread.
/// At this point, things unfold in one of two ways, depending on the race
/// condition. Either:
/// 3. The cancel task returns to the main thread and calls
/// BitsRequest::finish_cancel_action.
/// 4. If the cancel action succeeded, the appropriate status codes are set
/// and the CancelAction is set to RequestEndPending.
/// If the cancel action failed, the CancelAction is set to NotInProgress.
/// 5. The MonitorRunnable detects that the transfer has ended and calls
/// BitsRequest::on_stop, passing different status codes.
/// 6. BitsRequest::on_stop checks the CancelAction and
/// If the cancel action succeeded and RequestEndPending is set, the
/// status codes that were set by BitsRequest::finish_cancel_action are
/// left untouched.
/// If the cancel action failed and NotInProgress is set, the status codes
/// passed to BitsRequest::on_stop are set.
/// 7. onStopRequest is called with the correct status code.
/// Or, if MonitorRunnable calls on_stop before the cancel task can finish:
/// 3. The MonitorRunnable detects that the transfer has ended and calls
/// BitsRequest::on_stop, passing status codes to it.
/// 4. BitsRequest::on_stop checks the CancelAction, sees it is set to
/// InProgress, and sets it to RequestEndedWhileInProgress, carrying over
/// the status code from InProgress.
/// 5. BitsRequest::on_stop sets the status to the value passed to it, which
/// will be overwritten if the cancel action succeeds, but kept if it
/// fails.
/// 6. BitsRequest::on_stop returns early, without calling OnStopRequest.
/// 7. The cancel task returns to the main thread and calls
/// BitsRequest::finish_cancel_action.
/// 8. If the cancel action succeeded, the status codes are set from the
/// value stored in RequestEndedWhileInProgress.
/// If the cancel action failed, the status codes are not changed.
/// 9. The CancelAction is set to NotInProgress.
/// 10. BitsRequest::finish_cancel_action calls BitsRequest::on_stop without
/// passing it any status codes.
/// 11. onStopRequest is called with the correct status code.
#[derive(Clone, Copy, PartialEq)]
enum CancelAction {
NotInProgress,
InProgress(Option<nsresult>),
RequestEndedWhileInProgress(Option<nsresult>),
RequestEndPending,
}
#[xpcom(implement(nsIBitsRequest), nonatomic)]
pub struct BitsRequest {
bits_id: Guid,
bits_service: RefPtr<BitsService>,
// Stores the value to be returned by nsIRequest::IsPending.
download_pending: Cell<bool>,
// Stores the value to be returned by nsIRequest::GetStatus.
download_status_nsresult: Cell<nsresult>,
// Stores an ErrorType if the request has failed, or None to represent the
// success state.
download_status_error_type: Cell<Option<ErrorType>>,
// This option will be None only after OnStopRequest has been fired.
monitor_thread: Cell<Option<RefPtr<nsIThread>>>,
monitor_timeout_ms: u32,
observer: RefPtr<nsIRequestObserver>,
// started indicates whether or not OnStartRequest has been fired.
started: Cell<bool>,
// finished indicates whether or not we have called
// BitsService::dec_request_count() to (assuming that there are no other
// requests) shutdown the command thread.
finished: Cell<bool>,
cancel_action: Cell<CancelAction>,
}
impl fmt::Debug for BitsRequest {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "BitsRequest {{ id: {} }}", self.bits_id)
}
}
/// This implements the nsIBitsRequest interface, documented in nsIBits.idl, to
/// enable BITS job management. This interface deals only with BITS jobs that
/// already exist. Jobs can be created via BitsService, which will create a
/// BitsRequest for that job.
///
/// This is a primarily asynchronous interface, which is accomplished via
/// callbacks of type nsIBitsCallback. The callback is passed in as an argument
/// and is then passed off-thread via a Task. The Task interacts with BITS and
/// is dispatched back to the main thread with the BITS result. Back on the main
/// thread, it returns that result via the callback.
impl BitsRequest {
pub fn new(
id: Guid,
bits_service: RefPtr<BitsService>,
monitor_timeout_ms: u32,
observer: RefPtr<nsIRequestObserver>,
context: Option<RefPtr<nsISupports>>,
monitor_client: BitsMonitorClient,
action: ServiceAction,
) -> Result<RefPtr<BitsRequest>, BitsTaskError> {
let _ = context;
let action: Action = action.into();
let monitor_thread = create_thread("BitsMonitor").map_err(|rv| {
BitsTaskError::from_nsresult(FailedToStartThread, action, MainThread, rv)
})?;
// BitsRequest.drop() will call dec_request_count
bits_service.inc_request_count();
let request: RefPtr<BitsRequest> = BitsRequest::allocate(InitBitsRequest {
bits_id: id.clone(),
bits_service,
download_pending: Cell::new(true),
download_status_nsresult: Cell::new(NS_OK),
download_status_error_type: Cell::new(None),
monitor_thread: Cell::new(Some(monitor_thread.clone())),
monitor_timeout_ms,
observer,
started: Cell::new(false),
finished: Cell::new(false),
cancel_action: Cell::new(CancelAction::NotInProgress),
});
let monitor_runnable =
MonitorRunnable::new(request.clone(), id, monitor_timeout_ms, monitor_client);
if let Err(rv) = monitor_runnable.dispatch(monitor_thread.clone()) {
request.shutdown_monitor_thread();
return Err(BitsTaskError::from_nsresult(
FailedToDispatchRunnable,
action,
MainThread,
rv,
));
}
Ok(request)
}
pub fn get_monitor_thread(&self) -> Option<RefPtr<nsIThread>> {
let monitor_thread = self.monitor_thread.take();
self.monitor_thread.set(monitor_thread.clone());
monitor_thread
}
fn has_monitor_thread(&self) -> bool {
let maybe_monitor_thread = self.monitor_thread.take();
let transferred = maybe_monitor_thread.is_some();
self.monitor_thread.set(maybe_monitor_thread);
transferred
}
/// If this returns an true, it means that:
/// - The monitor thread and monitor runnable may have been shut down
/// - The BITS job is not in the TRANSFERRING state
/// - The download either completed, failed, or was cancelled
/// - The BITS job may or may not still need complete() or cancel() to be
/// called on it
fn request_has_transferred(&self) -> bool {
self.request_has_completed() || !self.has_monitor_thread()
}
/// If this returns an error, it means that:
/// - complete() or cancel() has been called on the BITS job.
/// - BitsService::dec_request_count has already been called.
/// - The BitsClient object that this request was using may have been
/// dropped.
fn request_has_completed(&self) -> bool {
self.finished.get()
}
fn shutdown_monitor_thread(&self) {
if let Some(monitor_thread) = self.monitor_thread.take() {
if let Err(rv) = unsafe { monitor_thread.AsyncShutdown() }.to_result() {
warn!("Failed to shut down monitor thread: {:?}", rv);
warn!("Releasing reference to thread that failed to shut down!");
}
}
}
/**
* To be called when the transfer starts. Fires observer.OnStartRequest exactly once.
*/
pub fn on_start(&self) {
if self.started.get() {
return;
}
self.started.set(true);
if let Err(rv) = unsafe { self.observer.OnStartRequest(self.coerce()) }.to_result() {
// This behavior is specified by nsIRequestObserver.
// See nsIRequestObserver.idl
info!(
"Cancelling download because OnStartRequest rejected with: {:?}",
rv
);
if let Err(rv) = self.cancel(NS_ERROR_ABORT, None) {
warn!("Failed to cancel download: {:?}", rv);
}
}
}
pub fn on_progress(&self, transferred_bytes: i64, total_bytes: i64) {
if let Some(progress_event_sink) = self.observer.query_interface::<nsIProgressEventSink>() {
unsafe {
progress_event_sink.OnProgress(self.coerce(), transferred_bytes, total_bytes);
}
}
}
/// To be called when the transfer stops (fails or completes). Fires
/// observer.OnStopRequest exactly once, though the call may be delayed to
/// resolve a race condition.
///
/// The status values, if passed, will be stored in download_status_nsresult
/// and download_status_error_type, unless they have been overridden by a
/// cancel action.
///
/// See the documentation for CancelAction for details.
pub fn on_stop(&self, maybe_status: Option<(nsresult, Option<ErrorType>)>) {
if !self.has_monitor_thread() {
// If the request has already stopped, don't stop it again
return;
}
match self.cancel_action.get() {
CancelAction::InProgress(saved_status)
| CancelAction::RequestEndedWhileInProgress(saved_status) => {
if let Some((status, result)) = maybe_status {
self.download_status_nsresult.set(status);
self.download_status_error_type.set(result);
}
info!("Deferring OnStopRequest until Cancel Task completes");
self.cancel_action
.set(CancelAction::RequestEndedWhileInProgress(saved_status));
return;
}
CancelAction::NotInProgress => {
if let Some((status, result)) = maybe_status {
self.download_status_nsresult.set(status);
self.download_status_error_type.set(result);
}
}
CancelAction::RequestEndPending => {
// Don't set the status variables if the end of this request was
// the result of a cancel action. The cancel action already set
// those values and they should not be changed.
// See the CancelAction documentation for details.
}
}
self.download_pending.set(false);
self.shutdown_monitor_thread();
unsafe {
self.observer
.OnStopRequest(self.coerce(), self.download_status_nsresult.get());
}
}
/// To be called after a cancel or complete task has run successfully. If
/// this is the only BitsRequest running, this will shut down
/// BitsService's command thread, destroying the BitsClient.
pub fn on_finished(&self) {
if self.finished.get() {
return;
}
self.finished.set(true);
self.bits_service.dec_request_count();
}
// Return the same thing for GetBitsId() and GetName().
xpcom_method!(
maybe_get_bits_id => GetBitsId() -> nsACString
);
xpcom_method!(
maybe_get_bits_id => GetName() -> nsACString
);
fn maybe_get_bits_id(&self) -> Result<nsCString, nsresult> {
Ok(self.get_bits_id())
}
pub fn get_bits_id(&self) -> nsCString {
nsCString::from(self.bits_id.to_string())
}
xpcom_method!(
get_bits_transfer_error_nsIBitsRequest => GetTransferError() -> i32
);
#[allow(non_snake_case)]
fn get_bits_transfer_error_nsIBitsRequest(&self) -> Result<i32, nsresult> {
let error_type = match self.download_status_error_type.get() {
None => nsIBits::ERROR_TYPE_SUCCESS,
Some(error_type) => error_type.bits_code(),
};
Ok(error_type)
}
xpcom_method!(
is_pending => IsPending() -> bool
);
fn is_pending(&self) -> Result<bool, nsresult> {
Ok(self.download_pending.get())
}
xpcom_method!(
get_status_nsIRequest => GetStatus() -> nsresult
);
#[allow(non_snake_case)]
fn get_status_nsIRequest(&self) -> Result<nsresult, nsresult> {
Ok(self.get_status())
}
pub fn get_status(&self) -> nsresult {
self.download_status_nsresult.get()
}
nsIBitsRequest_method!(
[Action::SetMonitorInterval]
change_monitor_interval => ChangeMonitorInterval(update_interval_ms: u32)
);
fn change_monitor_interval(
&self,
update_interval_ms: u32,
callback: &nsIBitsCallback,
) -> Result<(), BitsTaskError> {
if update_interval_ms == 0 || update_interval_ms >= self.monitor_timeout_ms {
return Err(BitsTaskError::new(
InvalidArgument,
Action::SetMonitorInterval,
Pretask,
));
}
if self.request_has_transferred() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::SetMonitorInterval,
Pretask,
));
}
let task: Box<ChangeMonitorIntervalTask> = Box::new(ChangeMonitorIntervalTask::new(
RefPtr::new(self),
self.bits_id.clone(),
update_interval_ms,
RefPtr::new(callback),
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::change_monitor_interval",
Action::SetMonitorInterval,
)
}
nsIBitsRequest_method!(
[Action::Cancel]
cancel_nsIBitsRequest => CancelAsync(status: nsresult)
);
#[allow(non_snake_case)]
fn cancel_nsIBitsRequest(
&self,
status: nsresult,
callback: &nsIBitsCallback,
) -> Result<(), BitsTaskError> {
self.cancel(status, Some(RefPtr::new(callback)))
}
xpcom_method!(
cancel_nsIRequest => Cancel(status: nsresult)
);
#[allow(non_snake_case)]
fn cancel_nsIRequest(&self, status: nsresult) -> Result<(), BitsTaskError> {
self.cancel(status, None)
}
fn cancel(
&self,
status: nsresult,
callback: Option<RefPtr<nsIBitsCallback>>,
) -> Result<(), BitsTaskError> {
if status.clone().succeeded() {
return Err(BitsTaskError::new(InvalidArgument, Action::Cancel, Pretask));
}
if self.request_has_completed() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::Cancel,
Pretask,
));
}
// If the transfer is still in a success state, cancelling it should move it to the failure
// state that was passed. But if the transfer already failed, the only reason to call cancel
// is to remove the job from BITS. So in that case, we should keep the failure status that
// we already have.
let maybe_status: Option<nsresult> = if self.download_status_nsresult.get().failed() {
None
} else {
Some(status)
};
if self.cancel_action.get() != CancelAction::NotInProgress {
return Err(BitsTaskError::new(
OperationAlreadyInProgress,
Action::Cancel,
Pretask,
));
}
self.cancel_action
.set(CancelAction::InProgress(maybe_status));
let task: Box<CancelTask> = Box::new(CancelTask::new(
RefPtr::new(self),
self.bits_id.clone(),
callback,
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::cancel",
Action::Cancel,
)
}
/// This function must be called when a cancel action completes.
///
/// See the documentation for CancelAction for details.
pub fn finish_cancel_action(&self, cancelled_successfully: bool) {
let (maybe_status, transfer_ended) = match self.cancel_action.get() {
CancelAction::InProgress(maybe_status) => (maybe_status, false),
CancelAction::RequestEndedWhileInProgress(maybe_status) => (maybe_status, true),
_ => {
error!("End of cancel action, but cancel action is not in progress!");
return;
}
};
info!(
"Finishing cancel action. cancel success = {}",
cancelled_successfully
);
if cancelled_successfully {
// If no status was provided, it is because this cancel action removed the BITS job
// after the job had already failed. Keep the original error codes.
if let Some(status) = maybe_status {
self.download_status_nsresult.set(status);
self.download_status_error_type
.set(Some(BitsStateCancelled));
}
}
let next_stage = if cancelled_successfully && !transfer_ended {
// This signals on_stop not to allow the status codes set above to
// be overridden by the ones passed to it.
CancelAction::RequestEndPending
} else {
CancelAction::NotInProgress
};
self.cancel_action.set(next_stage);
if cancelled_successfully {
self.on_finished();
}
if transfer_ended {
info!("Running deferred OnStopRequest");
self.on_stop(None);
}
}
nsIBitsRequest_method!(
[Action::SetPriority]
set_priority_high => SetPriorityHigh()
);
fn set_priority_high(&self, callback: &nsIBitsCallback) -> Result<(), BitsTaskError> {
self.set_priority(Priority::High, callback)
}
nsIBitsRequest_method!(
[Action::SetPriority]
set_priority_low => SetPriorityLow()
);
fn set_priority_low(&self, callback: &nsIBitsCallback) -> Result<(), BitsTaskError> {
self.set_priority(Priority::Low, callback)
}
fn set_priority(
&self,
priority: Priority,
callback: &nsIBitsCallback,
) -> Result<(), BitsTaskError> {
if self.request_has_transferred() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::SetPriority,
Pretask,
));
}
let task: Box<SetPriorityTask> = Box::new(SetPriorityTask::new(
RefPtr::new(self),
self.bits_id.clone(),
priority,
RefPtr::new(callback),
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::set_priority",
Action::SetPriority,
)
}
nsIBitsRequest_method!(
[Action::SetNoProgressTimeout]
set_no_progress_timeout => SetNoProgressTimeout(timeout_secs: u32)
);
fn set_no_progress_timeout(
&self,
timeout_secs: u32,
callback: &nsIBitsCallback,
) -> Result<(), BitsTaskError> {
if self.request_has_transferred() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::SetNoProgressTimeout,
Pretask,
));
}
let task: Box<SetNoProgressTimeoutTask> = Box::new(SetNoProgressTimeoutTask::new(
RefPtr::new(self),
self.bits_id.clone(),
timeout_secs,
RefPtr::new(callback),
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::set_no_progress_timeout",
Action::SetNoProgressTimeout,
)
}
nsIBitsRequest_method!(
[Action::Complete]
complete => Complete()
);
fn complete(&self, callback: &nsIBitsCallback) -> Result<(), BitsTaskError> {
if self.request_has_completed() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::Complete,
Pretask,
));
}
let task: Box<CompleteTask> = Box::new(CompleteTask::new(
RefPtr::new(self),
self.bits_id.clone(),
RefPtr::new(callback),
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::complete",
Action::Complete,
)
}
nsIBitsRequest_method!(
[Action::Suspend]
suspend_nsIBitsRequest => SuspendAsync()
);
#[allow(non_snake_case)]
fn suspend_nsIBitsRequest(&self, callback: &nsIBitsCallback) -> Result<(), BitsTaskError> {
self.suspend(Some(RefPtr::new(callback)))
}
xpcom_method!(
suspend_nsIRequest => Suspend()
);
#[allow(non_snake_case)]
fn suspend_nsIRequest(&self) -> Result<(), BitsTaskError> {
self.suspend(None)
}
fn suspend(&self, callback: Option<RefPtr<nsIBitsCallback>>) -> Result<(), BitsTaskError> {
if self.request_has_transferred() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::Suspend,
Pretask,
));
}
let task: Box<SuspendTask> = Box::new(SuspendTask::new(
RefPtr::new(self),
self.bits_id.clone(),
callback,
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::suspend",
Action::Suspend,
)
}
nsIBitsRequest_method!(
[Action::Resume]
resume_nsIBitsRequest => ResumeAsync()
);
#[allow(non_snake_case)]
fn resume_nsIBitsRequest(&self, callback: &nsIBitsCallback) -> Result<(), BitsTaskError> {
self.resume(Some(RefPtr::new(callback)))
}
xpcom_method!(
resume_nsIRequest => Resume()
);
#[allow(non_snake_case)]
fn resume_nsIRequest(&self) -> Result<(), BitsTaskError> {
self.resume(None)
}
fn resume(&self, callback: Option<RefPtr<nsIBitsCallback>>) -> Result<(), BitsTaskError> {
if self.request_has_transferred() {
return Err(BitsTaskError::new(
TransferAlreadyComplete,
Action::Resume,
Pretask,
));
}
let task: Box<ResumeTask> = Box::new(ResumeTask::new(
RefPtr::new(self),
self.bits_id.clone(),
callback,
));
self.bits_service.dispatch_runnable_to_command_thread(
task,
"BitsRequest::resume",
Action::Resume,
)
}
xpcom_method!(
get_load_group => GetLoadGroup() -> *const nsILoadGroup
);
/**
* As stated in nsIBits.idl, nsIBits interfaces are not expected to
* implement the loadGroup or loadFlags attributes. This implementation
* provides only null implementations only for these methods.
*/
fn get_load_group(&self) -> Result<RefPtr<nsILoadGroup>, nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
set_load_group => SetLoadGroup(_load_group: *const nsILoadGroup)
);
fn set_load_group(&self, _load_group: &nsILoadGroup) -> Result<(), nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
get_load_flags => GetLoadFlags() -> nsLoadFlags
);
fn get_load_flags(&self) -> Result<nsLoadFlags, nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
set_load_flags => SetLoadFlags(_load_flags: nsLoadFlags)
);
fn set_load_flags(&self, _load_flags: nsLoadFlags) -> Result<(), nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
get_trr_mode => GetTRRMode() -> u32
);
fn get_trr_mode(&self) -> Result<u32, nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
set_trr_mode => SetTRRMode(_trr_mode: u32)
);
fn set_trr_mode(&self, _trr_mode: u32) -> Result<(), nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
get_canceled_reason => GetCanceledReason() -> nsACString
);
fn get_canceled_reason(&self) -> Result<nsCString, nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
set_canceled_reason => SetCanceledReason(_reason: *const nsACString)
);
fn set_canceled_reason(&self, _reason: *const nsACString) -> Result<(), nsresult> {
Err(NS_ERROR_NOT_IMPLEMENTED)
}
xpcom_method!(
cancel_with_reason_nsIRequest => CancelWithReason(status: nsresult, _reason: *const nsACString)
);
#[allow(non_snake_case)]
fn cancel_with_reason_nsIRequest(
&self,
status: nsresult,
_reason: *const nsACString,
) -> Result<(), BitsTaskError> {
self.cancel(status, None)
}
}
impl Drop for BitsRequest {
fn drop(&mut self) {
// Make sure that the monitor thread gets cleaned up.
self.shutdown_monitor_thread();
// Make sure we tell BitsService that we are done with the command thread.
self.on_finished();
}
}