Struct Downloads

pub struct Downloads<ZN, ZV, ZSTip>
where
    ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static,
    ZN::Future: Send,
    ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static,
    ZV::Future: Send,
    ZSTip: ChainTip + Clone + Send + 'static,
{
    network: ZN,
    verifier: ZV,
    latest_chain_tip: ZSTip,
    lookahead_limit: usize,
    max_checkpoint_height: Height,
    past_lookahead_limit_sender: Arc<Mutex<Sender<bool>>>,
    past_lookahead_limit_receiver: WatchReceiver<bool>,
    pending: FuturesUnordered<JoinHandle<Result<(Height, Hash), (BlockDownloadVerifyError, Hash)>>>,
    cancel_handles: HashMap<Hash, Sender<()>>,
}

Represents a [Stream] of download and verification tasks during chain sync.

Fields

network: ZN

A service that forwards requests to connected peers, and returns their responses.

verifier: ZV

A service that verifies downloaded blocks.

latest_chain_tip: ZSTip

Allows efficient access to the best tip of the blockchain.

lookahead_limit: usize

The configured lookahead limit, after applying the minimum limit.

max_checkpoint_height: Height

The largest block height for the checkpoint verifier, based on the current config.

past_lookahead_limit_sender: Arc<Mutex<Sender<bool>>>

Sender that is set to true when the downloader is past the lookahead limit. This is based on the downloaded block height and the state tip height.

past_lookahead_limit_receiver: WatchReceiver<bool>

Receiver for past_lookahead_limit_sender, which is used to avoid accessing the mutex.

pending: FuturesUnordered<JoinHandle<Result<(Height, Hash), (BlockDownloadVerifyError, Hash)>>>

A list of pending block download and verify tasks.

cancel_handles: HashMap<Hash, Sender<()>>

A list of channels that can be used to cancel pending block download and verify tasks.

Implementations

impl<ZN, ZV, ZSTip> Downloads<ZN, ZV, ZSTip>

where ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static, ZN::Future: Send, ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static, ZV::Future: Send, ZSTip: ChainTip + Clone + Send + 'static,

pub(crate) fn project<'pin>( self: Pin<&'pin mut Self>, ) -> __DownloadsProjection<'pin, ZN, ZV, ZSTip>

pub(crate) fn project_ref<'pin>( self: Pin<&'pin Self>, ) -> __DownloadsProjectionRef<'pin, ZN, ZV, ZSTip>

impl<ZN, ZV, ZSTip> Downloads<ZN, ZV, ZSTip>

where ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static, ZN::Future: Send, ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static, ZV::Future: Send, ZSTip: ChainTip + Clone + Send + 'static,

pub fn new( network: ZN, verifier: ZV, latest_chain_tip: ZSTip, past_lookahead_limit_sender: Sender<bool>, lookahead_limit: usize, max_checkpoint_height: Height, ) -> Self

Initialize a new download stream with the provided network and verifier services.

Uses the latest_chain_tip and lookahead_limit to drop blocks that are too far ahead of the current state tip. Uses max_checkpoint_height to work around a known block timeout (#5125).

The Downloads stream is agnostic to the network policy, so retry and timeout limits should be applied to the network service passed into this constructor.

pub async fn download_and_verify( &mut self, hash: Hash, ) -> Result<(), BlockDownloadVerifyError>

Queue a block for download and verification.

This method waits for the network to become ready, and returns an error only if the network service fails. It returns immediately after queuing the request.

pub fn cancel_all(&mut self)

Cancel all running tasks and reset the downloader state.

pub fn in_flight(&mut self) -> usize

Get the number of currently in-flight download and verify tasks.

pub fn is_empty(&mut self) -> bool

Returns true if there are no in-flight download and verify tasks.

Trait Implementations

impl<ZN, ZV, ZSTip> Debug for Downloads<ZN, ZV, ZSTip>

where ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static + Debug, ZN::Future: Send, ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static + Debug, ZV::Future: Send, ZSTip: ChainTip + Clone + Send + 'static + Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<ZN, ZV, ZSTip> Stream for Downloads<ZN, ZV, ZSTip>

where ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static, ZN::Future: Send, ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static, ZV::Future: Send, ZSTip: ChainTip + Clone + Send + 'static,

type Item = Result<(Height, Hash), BlockDownloadVerifyError>

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<'pin, ZN, ZV, ZSTip> Unpin for Downloads<ZN, ZV, ZSTip>

where ZN: Service<Request, Response = Response, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + 'static, ZN::Future: Send, ZV: Service<Request, Response = Hash, Error = Box<dyn Error + Send + Sync + 'static>> + Send + Sync + Clone + 'static, ZV::Future: Send, ZSTip: ChainTip + Clone + Send + 'static, PinnedFieldsOf<__Downloads<'pin, ZN, ZV, ZSTip>>: Unpin,