//! future, as well as generate and broadcast funding transactions handle payment preimages and a
//! few other things.
-use ln::msgs;
-use ln::channelmanager::{PaymentPreimage, PaymentHash, PaymentSecret};
-use chain::transaction::OutPoint;
use chain::keysinterface::SpendableOutputDescriptor;
-use util::ser::{Writeable, Writer, MaybeReadable, Readable};
+use ln::channelmanager::PaymentId;
+use ln::channel::FUNDING_CONF_DEADLINE_BLOCKS;
+use ln::features::ChannelTypeFeatures;
+use ln::msgs;
+use ln::msgs::DecodeError;
+use ln::{PaymentPreimage, PaymentHash, PaymentSecret};
+use routing::gossip::NetworkUpdate;
+use util::ser::{BigSize, FixedLengthReader, Writeable, Writer, MaybeReadable, Readable, VecReadWrapper, VecWriteWrapper};
+use routing::router::{RouteHop, RouteParameters};
+use bitcoin::Transaction;
use bitcoin::blockdata::script::Script;
+use bitcoin::hashes::Hash;
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::PublicKey;
+use io;
+use prelude::*;
+use core::time::Duration;
+use core::ops::Deref;
+use sync::Arc;
+
+/// Some information provided on receipt of payment depends on whether the payment received is a
+/// spontaneous payment or a "conventional" lightning payment that's paying an invoice.
+#[derive(Clone, Debug)]
+pub enum PaymentPurpose {
+ /// Information for receiving a payment that we generated an invoice for.
+ InvoicePayment {
+ /// The preimage to the payment_hash, if the payment hash (and secret) were fetched via
+ /// [`ChannelManager::create_inbound_payment`]. If provided, this can be handed directly to
+ /// [`ChannelManager::claim_funds`].
+ ///
+ /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+ /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
+ payment_preimage: Option<PaymentPreimage>,
+ /// The "payment secret". This authenticates the sender to the recipient, preventing a
+ /// number of deanonymization attacks during the routing process.
+ /// It is provided here for your reference, however its accuracy is enforced directly by
+ /// [`ChannelManager`] using the values you previously provided to
+ /// [`ChannelManager::create_inbound_payment`] or
+ /// [`ChannelManager::create_inbound_payment_for_hash`].
+ ///
+ /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+ /// [`ChannelManager::create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
+ /// [`ChannelManager::create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
+ payment_secret: PaymentSecret,
+ },
+ /// Because this is a spontaneous payment, the payer generated their own preimage rather than us
+ /// (the payee) providing a preimage.
+ SpontaneousPayment(PaymentPreimage),
+}
-use bitcoin::secp256k1::key::PublicKey;
+impl_writeable_tlv_based_enum!(PaymentPurpose,
+ (0, InvoicePayment) => {
+ (0, payment_preimage, option),
+ (2, payment_secret, required),
+ };
+ (2, SpontaneousPayment)
+);
-use std::time::Duration;
+#[derive(Clone, Debug, PartialEq)]
+/// The reason the channel was closed. See individual variants more details.
+pub enum ClosureReason {
+ /// Closure generated from receiving a peer error message.
+ ///
+ /// Our counterparty may have broadcasted their latest commitment state, and we have
+ /// as well.
+ CounterpartyForceClosed {
+ /// The error which the peer sent us.
+ ///
+ /// The string should be sanitized before it is used (e.g emitted to logs
+ /// or printed to stdout). Otherwise, a well crafted error message may exploit
+ /// a security vulnerability in the terminal emulator or the logging subsystem.
+ peer_msg: String,
+ },
+ /// Closure generated from [`ChannelManager::force_close_channel`], called by the user.
+ ///
+ /// [`ChannelManager::force_close_channel`]: crate::ln::channelmanager::ChannelManager::force_close_channel.
+ HolderForceClosed,
+ /// The channel was closed after negotiating a cooperative close and we've now broadcasted
+ /// the cooperative close transaction. Note the shutdown may have been initiated by us.
+ //TODO: split between CounterpartyInitiated/LocallyInitiated
+ CooperativeClosure,
+ /// A commitment transaction was confirmed on chain, closing the channel. Most likely this
+ /// commitment transaction came from our counterparty, but it may also have come from
+ /// a copy of our own `ChannelMonitor`.
+ CommitmentTxConfirmed,
+ /// The funding transaction failed to confirm in a timely manner on an inbound channel.
+ FundingTimedOut,
+ /// Closure generated from processing an event, likely a HTLC forward/relay/reception.
+ ProcessingError {
+ /// A developer-readable error message which we generated.
+ err: String,
+ },
+ /// The peer disconnected prior to funding completing. In this case the spec mandates that we
+ /// forget the channel entirely - we can attempt again if the peer reconnects.
+ ///
+ /// In LDK versions prior to 0.0.107 this could also occur if we were unable to connect to the
+ /// peer because of mutual incompatibility between us and our channel counterparty.
+ DisconnectedPeer,
+ /// Closure generated from `ChannelManager::read` if the ChannelMonitor is newer than
+ /// the ChannelManager deserialized.
+ OutdatedChannelManager
+}
+
+impl core::fmt::Display for ClosureReason {
+ fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
+ f.write_str("Channel closed because ")?;
+ match self {
+ ClosureReason::CounterpartyForceClosed { peer_msg } => {
+ f.write_str("counterparty force-closed with message ")?;
+ f.write_str(&peer_msg)
+ },
+ ClosureReason::HolderForceClosed => f.write_str("user manually force-closed the channel"),
+ ClosureReason::CooperativeClosure => f.write_str("the channel was cooperatively closed"),
+ ClosureReason::CommitmentTxConfirmed => f.write_str("commitment or closing transaction was confirmed on chain."),
+ ClosureReason::FundingTimedOut => write!(f, "funding transaction failed to confirm within {} blocks", FUNDING_CONF_DEADLINE_BLOCKS),
+ ClosureReason::ProcessingError { err } => {
+ f.write_str("of an exception: ")?;
+ f.write_str(&err)
+ },
+ ClosureReason::DisconnectedPeer => f.write_str("the peer disconnected prior to the channel being funded"),
+ ClosureReason::OutdatedChannelManager => f.write_str("the ChannelManager read from disk was stale compared to ChannelMonitor(s)"),
+ }
+ }
+}
+
+impl_writeable_tlv_based_enum_upgradable!(ClosureReason,
+ (0, CounterpartyForceClosed) => { (1, peer_msg, required) },
+ (1, FundingTimedOut) => {},
+ (2, HolderForceClosed) => {},
+ (6, CommitmentTxConfirmed) => {},
+ (4, CooperativeClosure) => {},
+ (8, ProcessingError) => { (1, err, required) },
+ (10, DisconnectedPeer) => {},
+ (12, OutdatedChannelManager) => {},
+);
/// An Event which you should probably take some action in response to.
///
#[derive(Clone, Debug)]
pub enum Event {
/// Used to indicate that the client should generate a funding transaction with the given
- /// parameters and then call ChannelManager::funding_transaction_generated.
- /// Generated in ChannelManager message handling.
+ /// parameters and then call [`ChannelManager::funding_transaction_generated`].
+ /// Generated in [`ChannelManager`] message handling.
/// Note that *all inputs* in the funding transaction must spend SegWit outputs or your
/// counterparty can steal your funds!
+ ///
+ /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+ /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
FundingGenerationReady {
/// The random channel_id we picked which you'll need to pass into
- /// ChannelManager::funding_transaction_generated.
+ /// [`ChannelManager::funding_transaction_generated`].
+ ///
+ /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
temporary_channel_id: [u8; 32],
+ /// The counterparty's node_id, which you'll need to pass back into
+ /// [`ChannelManager::funding_transaction_generated`].
+ ///
+ /// [`ChannelManager::funding_transaction_generated`]: crate::ln::channelmanager::ChannelManager::funding_transaction_generated
+ counterparty_node_id: PublicKey,
/// The value, in satoshis, that the output should have.
channel_value_satoshis: u64,
/// The script which should be used in the transaction output.
output_script: Script,
- /// The value passed in to ChannelManager::create_channel
+ /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`], or 0 for
+ /// an inbound channel.
+ ///
+ /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
user_channel_id: u64,
},
- /// Used to indicate that the client may now broadcast the funding transaction it created for a
- /// channel. Broadcasting such a transaction prior to this event may lead to our counterparty
- /// trivially stealing all funds in the funding transaction!
- FundingBroadcastSafe {
- /// The output, which was passed to ChannelManager::funding_transaction_generated, which is
- /// now safe to broadcast.
- funding_txo: OutPoint,
- /// The value passed in to ChannelManager::create_channel
- user_channel_id: u64,
- },
- /// Indicates we've received money! Just gotta dig out that payment preimage and feed it to
- /// ChannelManager::claim_funds to get it....
- /// Note that if the preimage is not known or the amount paid is incorrect, you should call
- /// ChannelManager::fail_htlc_backwards to free up resources for this HTLC and avoid
+ /// Indicates we've received (an offer of) money! Just gotta dig out that payment preimage and
+ /// feed it to [`ChannelManager::claim_funds`] to get it....
+ ///
+ /// Note that if the preimage is not known, you should call
+ /// [`ChannelManager::fail_htlc_backwards`] to free up resources for this HTLC and avoid
/// network congestion.
- /// The amount paid should be considered 'incorrect' when it is less than or more than twice
- /// the amount expected.
- /// If you fail to call either ChannelManager::claim_funds or
- /// ChannelManager::fail_htlc_backwards within the HTLC's timeout, the HTLC will be
+ /// If you fail to call either [`ChannelManager::claim_funds`] or
+ /// [`ChannelManager::fail_htlc_backwards`] within the HTLC's timeout, the HTLC will be
/// automatically failed.
+ ///
+ /// # Note
+ /// LDK will not stop an inbound payment from being paid multiple times, so multiple
+ /// `PaymentReceived` events may be generated for the same payment.
+ ///
+ /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
+ /// [`ChannelManager::fail_htlc_backwards`]: crate::ln::channelmanager::ChannelManager::fail_htlc_backwards
PaymentReceived {
- /// The hash for which the preimage should be handed to the ChannelManager.
+ /// The hash for which the preimage should be handed to the ChannelManager. Note that LDK will
+ /// not stop you from registering duplicate payment hashes for inbound payments.
payment_hash: PaymentHash,
- /// The "payment secret". This authenticates the sender to the recipient, preventing a
- /// number of deanonymization attacks during the routing process.
- /// As nodes upgrade, the invoices you provide should likely migrate to setting the
- /// payment_secret feature to required, at which point you should fail_backwards any HTLCs
- /// which have a None here.
- /// Until then, however, values of None should be ignored, and only incorrect Some values
- /// should result in an HTLC fail_backwards.
- /// Note that, in any case, this value must be passed as-is to any fail or claim calls as
- /// the HTLC index includes this value.
- payment_secret: Option<PaymentSecret>,
- /// The value, in thousandths of a satoshi, that this payment is for. Note that you must
- /// compare this to the expected value before accepting the payment (as otherwise you are
- /// providing proof-of-payment for less than the value you expected!).
- amt: u64,
- },
- /// Indicates an outbound payment we made succeeded (ie it made it all the way to its target
+ /// The value, in thousandths of a satoshi, that this payment is for.
+ amount_msat: u64,
+ /// Information for claiming this received payment, based on whether the purpose of the
+ /// payment is to pay an invoice or to send a spontaneous payment.
+ purpose: PaymentPurpose,
+ },
+ /// Indicates a payment has been claimed and we've received money!
+ ///
+ /// This most likely occurs when [`ChannelManager::claim_funds`] has been called in response
+ /// to an [`Event::PaymentReceived`]. However, if we previously crashed during a
+ /// [`ChannelManager::claim_funds`] call you may see this event without a corresponding
+ /// [`Event::PaymentReceived`] event.
+ ///
+ /// # Note
+ /// LDK will not stop an inbound payment from being paid multiple times, so multiple
+ /// `PaymentReceived` events may be generated for the same payment. If you then call
+ /// [`ChannelManager::claim_funds`] twice for the same [`Event::PaymentReceived`] you may get
+ /// multiple `PaymentClaimed` events.
+ ///
+ /// [`ChannelManager::claim_funds`]: crate::ln::channelmanager::ChannelManager::claim_funds
+ PaymentClaimed {
+ /// The payment hash of the claimed payment. Note that LDK will not stop you from
+ /// registering duplicate payment hashes for inbound payments.
+ payment_hash: PaymentHash,
+ /// The value, in thousandths of a satoshi, that this payment is for.
+ amount_msat: u64,
+ /// The purpose of this claimed payment, i.e. whether the payment was for an invoice or a
+ /// spontaneous payment.
+ purpose: PaymentPurpose,
+ },
+ /// Indicates an outbound payment we made succeeded (i.e. it made it all the way to its target
/// and we got back the payment preimage for it).
- /// Note that duplicative PaymentSent Events may be generated - it is your responsibility to
- /// deduplicate them by payment_preimage (which MUST be unique)!
+ ///
+ /// Note for MPP payments: in rare cases, this event may be preceded by a `PaymentPathFailed`
+ /// event. In this situation, you SHOULD treat this payment as having succeeded.
PaymentSent {
+ /// The id returned by [`ChannelManager::send_payment`] and used with
+ /// [`ChannelManager::retry_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+ payment_id: Option<PaymentId>,
/// The preimage to the hash given to ChannelManager::send_payment.
/// Note that this serves as a payment receipt, if you wish to have such a thing, you must
/// store it somehow!
payment_preimage: PaymentPreimage,
+ /// The hash that was given to [`ChannelManager::send_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ payment_hash: PaymentHash,
+ /// The total fee which was spent at intermediate hops in this payment, across all paths.
+ ///
+ /// Note that, like [`Route::get_total_fees`] this does *not* include any potential
+ /// overpayment to the recipient node.
+ ///
+ /// If the recipient or an intermediate node misbehaves and gives us free money, this may
+ /// overstate the amount paid, though this is unlikely.
+ ///
+ /// [`Route::get_total_fees`]: crate::routing::router::Route::get_total_fees
+ fee_paid_msat: Option<u64>,
},
- /// Indicates an outbound payment we made failed. Probably some intermediary node dropped
- /// something. You may wish to retry with a different route.
- /// Note that duplicative PaymentFailed Events may be generated - it is your responsibility to
- /// deduplicate them by payment_hash (which MUST be unique)!
+ /// Indicates an outbound payment failed. Individual [`Event::PaymentPathFailed`] events
+ /// provide failure information for each MPP part in the payment.
+ ///
+ /// This event is provided once there are no further pending HTLCs for the payment and the
+ /// payment is no longer retryable, either due to a several-block timeout or because
+ /// [`ChannelManager::abandon_payment`] was previously called for the corresponding payment.
+ ///
+ /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
PaymentFailed {
- /// The hash which was given to ChannelManager::send_payment.
+ /// The id returned by [`ChannelManager::send_payment`] and used with
+ /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+ /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
+ payment_id: PaymentId,
+ /// The hash that was given to [`ChannelManager::send_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ payment_hash: PaymentHash,
+ },
+ /// Indicates that a path for an outbound payment was successful.
+ ///
+ /// Always generated after [`Event::PaymentSent`] and thus useful for scoring channels. See
+ /// [`Event::PaymentSent`] for obtaining the payment preimage.
+ PaymentPathSuccessful {
+ /// The id returned by [`ChannelManager::send_payment`] and used with
+ /// [`ChannelManager::retry_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+ payment_id: PaymentId,
+ /// The hash that was given to [`ChannelManager::send_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ payment_hash: Option<PaymentHash>,
+ /// The payment path that was successful.
+ ///
+ /// May contain a closed channel if the HTLC sent along the path was fulfilled on chain.
+ path: Vec<RouteHop>,
+ },
+ /// Indicates an outbound HTLC we sent failed. Probably some intermediary node dropped
+ /// something. You may wish to retry with a different route.
+ ///
+ /// Note that this does *not* indicate that all paths for an MPP payment have failed, see
+ /// [`Event::PaymentFailed`] and [`all_paths_failed`].
+ ///
+ /// [`all_paths_failed`]: Self::PaymentPathFailed::all_paths_failed
+ PaymentPathFailed {
+ /// The id returned by [`ChannelManager::send_payment`] and used with
+ /// [`ChannelManager::retry_payment`] and [`ChannelManager::abandon_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
+ /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
+ /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
+ payment_id: Option<PaymentId>,
+ /// The hash that was given to [`ChannelManager::send_payment`].
+ ///
+ /// [`ChannelManager::send_payment`]: crate::ln::channelmanager::ChannelManager::send_payment
payment_hash: PaymentHash,
/// Indicates the payment was rejected for some reason by the recipient. This implies that
/// the payment has failed, not just the route in question. If this is not set, you may
/// retry the payment via a different route.
rejected_by_dest: bool,
+ /// Any failure information conveyed via the Onion return packet by a node along the failed
+ /// payment route.
+ ///
+ /// Should be applied to the [`NetworkGraph`] so that routing decisions can take into
+ /// account the update.
+ ///
+ /// [`NetworkGraph`]: crate::routing::gossip::NetworkGraph
+ network_update: Option<NetworkUpdate>,
+ /// For both single-path and multi-path payments, this is set if all paths of the payment have
+ /// failed. This will be set to false if (1) this is an MPP payment and (2) other parts of the
+ /// larger MPP payment were still in flight when this event was generated.
+ ///
+ /// Note that if you are retrying individual MPP parts, using this value to determine if a
+ /// payment has fully failed is race-y. Because multiple failures can happen prior to events
+ /// being processed, you may retry in response to a first failure, with a second failure
+ /// (with `all_paths_failed` set) still pending. Then, when the second failure is processed
+ /// you will see `all_paths_failed` set even though the retry of the first failure still
+ /// has an associated in-flight HTLC. See (1) for an example of such a failure.
+ ///
+ /// If you wish to retry individual MPP parts and learn when a payment has failed, you must
+ /// call [`ChannelManager::abandon_payment`] and wait for a [`Event::PaymentFailed`] event.
+ ///
+ /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
+ ///
+ /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
+ all_paths_failed: bool,
+ /// The payment path that failed.
+ path: Vec<RouteHop>,
+ /// The channel responsible for the failed payment path.
+ ///
+ /// Note that for route hints or for the first hop in a path this may be an SCID alias and
+ /// may not refer to a channel in the public network graph. These aliases may also collide
+ /// with channels in the public network graph.
+ ///
+ /// If this is `Some`, then the corresponding channel should be avoided when the payment is
+ /// retried. May be `None` for older [`Event`] serializations.
+ short_channel_id: Option<u64>,
+ /// Parameters needed to compute a new [`Route`] when retrying the failed payment path.
+ ///
+ /// See [`find_route`] for details.
+ ///
+ /// [`Route`]: crate::routing::router::Route
+ /// [`find_route`]: crate::routing::router::find_route
+ retry: Option<RouteParameters>,
#[cfg(test)]
error_code: Option<u16>,
#[cfg(test)]
error_data: Option<Vec<u8>>,
},
- /// Used to indicate that ChannelManager::process_pending_htlc_forwards should be called at a
- /// time in the future.
+ /// Used to indicate that [`ChannelManager::process_pending_htlc_forwards`] should be called at
+ /// a time in the future.
+ ///
+ /// [`ChannelManager::process_pending_htlc_forwards`]: crate::ln::channelmanager::ChannelManager::process_pending_htlc_forwards
PendingHTLCsForwardable {
/// The minimum amount of time that should be waited prior to calling
/// process_pending_htlc_forwards. To increase the effort required to correlate payments,
/// now + 5*time_forwardable).
time_forwardable: Duration,
},
- /// Used to indicate that an output was generated on-chain which you should know how to spend.
+ /// Used to indicate that an output which you should know how to spend was confirmed on chain
+ /// and is now spendable.
/// Such an output will *not* ever be spent by rust-lightning, and are not at risk of your
/// counterparty spending them due to some kind of timeout. Thus, you need to store them
/// somewhere and spend them when you create on-chain transactions.
/// The outputs which you should store as spendable by you.
outputs: Vec<SpendableOutputDescriptor>,
},
+ /// This event is generated when a payment has been successfully forwarded through us and a
+ /// forwarding fee earned.
+ PaymentForwarded {
+ /// The incoming channel between the previous node and us. This is only `None` for events
+ /// generated or serialized by versions prior to 0.0.107.
+ prev_channel_id: Option<[u8; 32]>,
+ /// The outgoing channel between the next node and us. This is only `None` for events
+ /// generated or serialized by versions prior to 0.0.107.
+ next_channel_id: Option<[u8; 32]>,
+ /// The fee, in milli-satoshis, which was earned as a result of the payment.
+ ///
+ /// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
+ /// was pending, the amount the next hop claimed will have been rounded down to the nearest
+ /// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
+ /// claimed the full value in millisatoshis from the source. In this case,
+ /// `claim_from_onchain_tx` will be set.
+ ///
+ /// If the channel which sent us the payment has been force-closed, we will claim the funds
+ /// via an on-chain transaction. In that case we do not yet know the on-chain transaction
+ /// fees which we will spend and will instead set this to `None`. It is possible duplicate
+ /// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
+ /// `None`.
+ fee_earned_msat: Option<u64>,
+ /// If this is `true`, the forwarded HTLC was claimed by our counterparty via an on-chain
+ /// transaction.
+ claim_from_onchain_tx: bool,
+ },
+ /// Used to indicate that a previously opened channel with the given `channel_id` is in the
+ /// process of closure.
+ ChannelClosed {
+ /// The channel_id of the channel which has been closed. Note that on-chain transactions
+ /// resolving the channel are likely still awaiting confirmation.
+ channel_id: [u8; 32],
+ /// The `user_channel_id` value passed in to [`ChannelManager::create_channel`] for outbound
+ /// channels, or to [`ChannelManager::accept_inbound_channel`] for inbound channels if
+ /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true. Otherwise
+ /// `user_channel_id` will be 0 for an inbound channel.
+ /// This will always be zero for objects serialized with LDK versions prior to 0.0.102.
+ ///
+ /// [`ChannelManager::create_channel`]: crate::ln::channelmanager::ChannelManager::create_channel
+ /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
+ /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
+ user_channel_id: u64,
+ /// The reason the channel was closed.
+ reason: ClosureReason
+ },
+ /// Used to indicate to the user that they can abandon the funding transaction and recycle the
+ /// inputs for another purpose.
+ DiscardFunding {
+ /// The channel_id of the channel which has been closed.
+ channel_id: [u8; 32],
+ /// The full transaction received from the user
+ transaction: Transaction
+ },
+ /// Indicates a request to open a new channel by a peer.
+ ///
+ /// To accept the request, call [`ChannelManager::accept_inbound_channel`]. To reject the
+ /// request, call [`ChannelManager::force_close_without_broadcasting_txn`].
+ ///
+ /// The event is only triggered when a new open channel request is received and the
+ /// [`UserConfig::manually_accept_inbound_channels`] config flag is set to true.
+ ///
+ /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
+ /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
+ /// [`UserConfig::manually_accept_inbound_channels`]: crate::util::config::UserConfig::manually_accept_inbound_channels
+ OpenChannelRequest {
+ /// The temporary channel ID of the channel requested to be opened.
+ ///
+ /// When responding to the request, the `temporary_channel_id` should be passed
+ /// back to the ChannelManager through [`ChannelManager::accept_inbound_channel`] to accept,
+ /// or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject.
+ ///
+ /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
+ /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
+ temporary_channel_id: [u8; 32],
+ /// The node_id of the counterparty requesting to open the channel.
+ ///
+ /// When responding to the request, the `counterparty_node_id` should be passed
+ /// back to the `ChannelManager` through [`ChannelManager::accept_inbound_channel`] to
+ /// accept the request, or through [`ChannelManager::force_close_without_broadcasting_txn`] to reject the
+ /// request.
+ ///
+ /// [`ChannelManager::accept_inbound_channel`]: crate::ln::channelmanager::ChannelManager::accept_inbound_channel
+ /// [`ChannelManager::force_close_without_broadcasting_txn`]: crate::ln::channelmanager::ChannelManager::force_close_without_broadcasting_txn
+ counterparty_node_id: PublicKey,
+ /// The channel value of the requested channel.
+ funding_satoshis: u64,
+ /// Our starting balance in the channel if the request is accepted, in milli-satoshi.
+ push_msat: u64,
+ /// The features that this channel will operate with. If you reject the channel, a
+ /// well-behaved counterparty may automatically re-attempt the channel with a new set of
+ /// feature flags.
+ ///
+ /// Note that if [`ChannelTypeFeatures::supports_scid_privacy`] returns true on this type,
+ /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
+ /// 0.0.106.
+ ///
+ /// Furthermore, note that if [`ChannelTypeFeatures::supports_zero_conf`] returns true on this type,
+ /// the resulting [`ChannelManager`] will not be readable by versions of LDK prior to
+ /// 0.0.107. Channels setting this type also need to get manually accepted via
+ /// [`crate::ln::channelmanager::ChannelManager::accept_inbound_channel_from_trusted_peer_0conf`],
+ /// or will be rejected otherwise.
+ ///
+ /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+ channel_type: ChannelTypeFeatures,
+ },
}
impl Writeable for Event {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+ fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
match self {
&Event::FundingGenerationReady { .. } => {
0u8.write(writer)?;
// We never write out FundingGenerationReady events as, upon disconnection, peers
// drop any channels which have not yet exchanged funding_signed.
},
- &Event::FundingBroadcastSafe { ref funding_txo, ref user_channel_id } => {
+ &Event::PaymentReceived { ref payment_hash, ref amount_msat, ref purpose } => {
1u8.write(writer)?;
- funding_txo.write(writer)?;
- user_channel_id.write(writer)?;
+ let mut payment_secret = None;
+ let payment_preimage;
+ match &purpose {
+ PaymentPurpose::InvoicePayment { payment_preimage: preimage, payment_secret: secret } => {
+ payment_secret = Some(secret);
+ payment_preimage = *preimage;
+ },
+ PaymentPurpose::SpontaneousPayment(preimage) => {
+ payment_preimage = Some(*preimage);
+ }
+ }
+ write_tlv_fields!(writer, {
+ (0, payment_hash, required),
+ (2, payment_secret, option),
+ (4, amount_msat, required),
+ (6, 0u64, required), // user_payment_id required for compatibility with 0.0.103 and earlier
+ (8, payment_preimage, option),
+ });
},
- &Event::PaymentReceived { ref payment_hash, ref payment_secret, ref amt } => {
+ &Event::PaymentSent { ref payment_id, ref payment_preimage, ref payment_hash, ref fee_paid_msat } => {
2u8.write(writer)?;
- payment_hash.write(writer)?;
- payment_secret.write(writer)?;
- amt.write(writer)?;
- },
- &Event::PaymentSent { ref payment_preimage } => {
- 3u8.write(writer)?;
- payment_preimage.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, payment_preimage, required),
+ (1, payment_hash, required),
+ (3, payment_id, option),
+ (5, fee_paid_msat, option),
+ });
},
- &Event::PaymentFailed { ref payment_hash, ref rejected_by_dest,
+ &Event::PaymentPathFailed {
+ ref payment_id, ref payment_hash, ref rejected_by_dest, ref network_update,
+ ref all_paths_failed, ref path, ref short_channel_id, ref retry,
#[cfg(test)]
ref error_code,
#[cfg(test)]
ref error_data,
} => {
- 4u8.write(writer)?;
- payment_hash.write(writer)?;
- rejected_by_dest.write(writer)?;
+ 3u8.write(writer)?;
#[cfg(test)]
error_code.write(writer)?;
#[cfg(test)]
error_data.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, payment_hash, required),
+ (1, network_update, option),
+ (2, rejected_by_dest, required),
+ (3, all_paths_failed, required),
+ (5, path, vec_type),
+ (7, short_channel_id, option),
+ (9, retry, option),
+ (11, payment_id, option),
+ });
},
&Event::PendingHTLCsForwardable { time_forwardable: _ } => {
- 5u8.write(writer)?;
- // We don't write the time_fordwardable out at all, as we presume when the user
- // deserializes us at least that much time has elapsed.
+ 4u8.write(writer)?;
+ // Note that we now ignore these on the read end as we'll re-generate them in
+ // ChannelManager, we write them here only for backwards compatibility.
},
&Event::SpendableOutputs { ref outputs } => {
- 6u8.write(writer)?;
- (outputs.len() as u64).write(writer)?;
- for output in outputs.iter() {
- output.write(writer)?;
- }
+ 5u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, VecWriteWrapper(outputs), required),
+ });
+ },
+ &Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id } => {
+ 7u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, fee_earned_msat, option),
+ (1, prev_channel_id, option),
+ (2, claim_from_onchain_tx, required),
+ (3, next_channel_id, option),
+ });
+ },
+ &Event::ChannelClosed { ref channel_id, ref user_channel_id, ref reason } => {
+ 9u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, channel_id, required),
+ (1, user_channel_id, required),
+ (2, reason, required)
+ });
},
+ &Event::DiscardFunding { ref channel_id, ref transaction } => {
+ 11u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, channel_id, required),
+ (2, transaction, required)
+ })
+ },
+ &Event::PaymentPathSuccessful { ref payment_id, ref payment_hash, ref path } => {
+ 13u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, payment_id, required),
+ (2, payment_hash, option),
+ (4, path, vec_type)
+ })
+ },
+ &Event::PaymentFailed { ref payment_id, ref payment_hash } => {
+ 15u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, payment_id, required),
+ (2, payment_hash, required),
+ })
+ },
+ &Event::OpenChannelRequest { .. } => {
+ 17u8.write(writer)?;
+ // We never write the OpenChannelRequest events as, upon disconnection, peers
+ // drop any channels which have not yet exchanged funding_signed.
+ },
+ &Event::PaymentClaimed { ref payment_hash, ref amount_msat, ref purpose } => {
+ 19u8.write(writer)?;
+ write_tlv_fields!(writer, {
+ (0, payment_hash, required),
+ (2, purpose, required),
+ (4, amount_msat, required),
+ });
+ },
+ // Note that, going forward, all new events must only write data inside of
+ // `write_tlv_fields`. Versions 0.0.101+ will ignore odd-numbered events that write
+ // data via `write_tlv_fields`.
}
Ok(())
}
}
impl MaybeReadable for Event {
- fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
+ fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, msgs::DecodeError> {
match Readable::read(reader)? {
+ // Note that we do not write a length-prefixed TLV for FundingGenerationReady events,
+ // unlike all other events, thus we return immediately here.
0u8 => Ok(None),
- 1u8 => Ok(Some(Event::FundingBroadcastSafe {
- funding_txo: Readable::read(reader)?,
- user_channel_id: Readable::read(reader)?,
- })),
- 2u8 => Ok(Some(Event::PaymentReceived {
- payment_hash: Readable::read(reader)?,
- payment_secret: Readable::read(reader)?,
- amt: Readable::read(reader)?,
- })),
- 3u8 => Ok(Some(Event::PaymentSent {
- payment_preimage: Readable::read(reader)?,
- })),
- 4u8 => Ok(Some(Event::PaymentFailed {
- payment_hash: Readable::read(reader)?,
- rejected_by_dest: Readable::read(reader)?,
+ 1u8 => {
+ let f = || {
+ let mut payment_hash = PaymentHash([0; 32]);
+ let mut payment_preimage = None;
+ let mut payment_secret = None;
+ let mut amount_msat = 0;
+ let mut _user_payment_id = None::<u64>; // For compatibility with 0.0.103 and earlier
+ read_tlv_fields!(reader, {
+ (0, payment_hash, required),
+ (2, payment_secret, option),
+ (4, amount_msat, required),
+ (6, _user_payment_id, option),
+ (8, payment_preimage, option),
+ });
+ let purpose = match payment_secret {
+ Some(secret) => PaymentPurpose::InvoicePayment {
+ payment_preimage,
+ payment_secret: secret
+ },
+ None if payment_preimage.is_some() => PaymentPurpose::SpontaneousPayment(payment_preimage.unwrap()),
+ None => return Err(msgs::DecodeError::InvalidValue),
+ };
+ Ok(Some(Event::PaymentReceived {
+ payment_hash,
+ amount_msat,
+ purpose,
+ }))
+ };
+ f()
+ },
+ 2u8 => {
+ let f = || {
+ let mut payment_preimage = PaymentPreimage([0; 32]);
+ let mut payment_hash = None;
+ let mut payment_id = None;
+ let mut fee_paid_msat = None;
+ read_tlv_fields!(reader, {
+ (0, payment_preimage, required),
+ (1, payment_hash, option),
+ (3, payment_id, option),
+ (5, fee_paid_msat, option),
+ });
+ if payment_hash.is_none() {
+ payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner()));
+ }
+ Ok(Some(Event::PaymentSent {
+ payment_id,
+ payment_preimage,
+ payment_hash: payment_hash.unwrap(),
+ fee_paid_msat,
+ }))
+ };
+ f()
+ },
+ 3u8 => {
+ let f = || {
#[cfg(test)]
- error_code: Readable::read(reader)?,
+ let error_code = Readable::read(reader)?;
#[cfg(test)]
- error_data: Readable::read(reader)?,
- })),
- 5u8 => Ok(Some(Event::PendingHTLCsForwardable {
- time_forwardable: Duration::from_secs(0)
- })),
- 6u8 => {
- let outputs_len: u64 = Readable::read(reader)?;
- let mut outputs = Vec::new();
- for _ in 0..outputs_len {
- outputs.push(Readable::read(reader)?);
- }
- Ok(Some(Event::SpendableOutputs { outputs }))
+ let error_data = Readable::read(reader)?;
+ let mut payment_hash = PaymentHash([0; 32]);
+ let mut rejected_by_dest = false;
+ let mut network_update = None;
+ let mut all_paths_failed = Some(true);
+ let mut path: Option<Vec<RouteHop>> = Some(vec![]);
+ let mut short_channel_id = None;
+ let mut retry = None;
+ let mut payment_id = None;
+ read_tlv_fields!(reader, {
+ (0, payment_hash, required),
+ (1, network_update, ignorable),
+ (2, rejected_by_dest, required),
+ (3, all_paths_failed, option),
+ (5, path, vec_type),
+ (7, short_channel_id, option),
+ (9, retry, option),
+ (11, payment_id, option),
+ });
+ Ok(Some(Event::PaymentPathFailed {
+ payment_id,
+ payment_hash,
+ rejected_by_dest,
+ network_update,
+ all_paths_failed: all_paths_failed.unwrap(),
+ path: path.unwrap(),
+ short_channel_id,
+ retry,
+ #[cfg(test)]
+ error_code,
+ #[cfg(test)]
+ error_data,
+ }))
+ };
+ f()
+ },
+ 4u8 => Ok(None),
+ 5u8 => {
+ let f = || {
+ let mut outputs = VecReadWrapper(Vec::new());
+ read_tlv_fields!(reader, {
+ (0, outputs, required),
+ });
+ Ok(Some(Event::SpendableOutputs { outputs: outputs.0 }))
+ };
+ f()
+ },
+ 7u8 => {
+ let f = || {
+ let mut fee_earned_msat = None;
+ let mut prev_channel_id = None;
+ let mut claim_from_onchain_tx = false;
+ let mut next_channel_id = None;
+ read_tlv_fields!(reader, {
+ (0, fee_earned_msat, option),
+ (1, prev_channel_id, option),
+ (2, claim_from_onchain_tx, required),
+ (3, next_channel_id, option),
+ });
+ Ok(Some(Event::PaymentForwarded { fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id }))
+ };
+ f()
+ },
+ 9u8 => {
+ let f = || {
+ let mut channel_id = [0; 32];
+ let mut reason = None;
+ let mut user_channel_id_opt = None;
+ read_tlv_fields!(reader, {
+ (0, channel_id, required),
+ (1, user_channel_id_opt, option),
+ (2, reason, ignorable),
+ });
+ if reason.is_none() { return Ok(None); }
+ let user_channel_id = if let Some(id) = user_channel_id_opt { id } else { 0 };
+ Ok(Some(Event::ChannelClosed { channel_id, user_channel_id, reason: reason.unwrap() }))
+ };
+ f()
+ },
+ 11u8 => {
+ let f = || {
+ let mut channel_id = [0; 32];
+ let mut transaction = Transaction{ version: 2, lock_time: 0, input: Vec::new(), output: Vec::new() };
+ read_tlv_fields!(reader, {
+ (0, channel_id, required),
+ (2, transaction, required),
+ });
+ Ok(Some(Event::DiscardFunding { channel_id, transaction } ))
+ };
+ f()
+ },
+ 13u8 => {
+ let f = || {
+ let mut payment_id = PaymentId([0; 32]);
+ let mut payment_hash = None;
+ let mut path: Option<Vec<RouteHop>> = Some(vec![]);
+ read_tlv_fields!(reader, {
+ (0, payment_id, required),
+ (2, payment_hash, option),
+ (4, path, vec_type),
+ });
+ Ok(Some(Event::PaymentPathSuccessful {
+ payment_id,
+ payment_hash,
+ path: path.unwrap(),
+ }))
+ };
+ f()
+ },
+ 15u8 => {
+ let f = || {
+ let mut payment_hash = PaymentHash([0; 32]);
+ let mut payment_id = PaymentId([0; 32]);
+ read_tlv_fields!(reader, {
+ (0, payment_id, required),
+ (2, payment_hash, required),
+ });
+ Ok(Some(Event::PaymentFailed {
+ payment_id,
+ payment_hash,
+ }))
+ };
+ f()
+ },
+ 17u8 => {
+ // Value 17 is used for `Event::OpenChannelRequest`.
+ Ok(None)
+ },
+ 19u8 => {
+ let f = || {
+ let mut payment_hash = PaymentHash([0; 32]);
+ let mut purpose = None;
+ let mut amount_msat = 0;
+ read_tlv_fields!(reader, {
+ (0, payment_hash, required),
+ (2, purpose, ignorable),
+ (4, amount_msat, required),
+ });
+ if purpose.is_none() { return Ok(None); }
+ Ok(Some(Event::PaymentClaimed {
+ payment_hash,
+ purpose: purpose.unwrap(),
+ amount_msat,
+ }))
+ };
+ f()
+ },
+ // Versions prior to 0.0.100 did not ignore odd types, instead returning InvalidValue.
+ // Version 0.0.100 failed to properly ignore odd types, possibly resulting in corrupt
+ // reads.
+ x if x % 2 == 1 => {
+ // If the event is of unknown type, assume it was written with `write_tlv_fields`,
+ // which prefixes the whole thing with a length BigSize. Because the event is
+ // odd-type unknown, we should treat it as `Ok(None)` even if it has some TLV
+ // fields that are even. Thus, we avoid using `read_tlv_fields` and simply read
+ // exactly the number of bytes specified, ignoring them entirely.
+ let tlv_len: BigSize = Readable::read(reader)?;
+ FixedLengthReader::new(reader, tlv_len.0)
+ .eat_remaining().map_err(|_| msgs::DecodeError::ShortRead)?;
+ Ok(None)
},
_ => Err(msgs::DecodeError::InvalidValue)
}
/// An event generated by ChannelManager which indicates a message should be sent to a peer (or
/// broadcast to most peers).
/// These events are handled by PeerManager::process_events if you are using a PeerManager.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
pub enum MessageSendEvent {
/// Used to indicate that we've accepted a channel open and should send the accept_channel
/// message provided to the given peer.
/// The message which should be sent.
msg: msgs::FundingSigned,
},
- /// Used to indicate that a funding_locked message should be sent to the peer with the given node_id.
- SendFundingLocked {
+ /// Used to indicate that a channel_ready message should be sent to the peer with the given node_id.
+ SendChannelReady {
/// The node_id of the node which should receive these message(s)
node_id: PublicKey,
- /// The funding_locked message which should be sent.
- msg: msgs::FundingLocked,
+ /// The channel_ready message which should be sent.
+ msg: msgs::ChannelReady,
},
/// Used to indicate that an announcement_signatures message should be sent to the peer with the given node_id.
SendAnnouncementSignatures {
/// The channel_update which should be sent.
msg: msgs::ChannelUpdate,
},
+ /// Used to indicate that a channel_update should be sent to a single peer.
+ /// In contrast to [`Self::BroadcastChannelUpdate`], this is used when the channel is a
+ /// private channel and we shouldn't be informing all of our peers of channel parameters.
+ SendChannelUpdate {
+ /// The node_id of the node which should receive this message
+ node_id: PublicKey,
+ /// The channel_update which should be sent.
+ msg: msgs::ChannelUpdate,
+ },
/// Broadcast an error downstream to be handled
HandleError {
/// The node_id of the node which should receive this message
/// The action which should be taken.
action: msgs::ErrorAction
},
- /// When a payment fails we may receive updates back from the hop where it failed. In such
- /// cases this event is generated so that we can inform the network graph of this information.
- PaymentFailureNetworkUpdate {
- /// The channel/node update which should be sent to NetGraphMsgHandler
- update: msgs::HTLCFailChannelUpdate,
- }
+ /// Query a peer for channels with funding transaction UTXOs in a block range.
+ SendChannelRangeQuery {
+ /// The node_id of this message recipient
+ node_id: PublicKey,
+ /// The query_channel_range which should be sent.
+ msg: msgs::QueryChannelRange,
+ },
+ /// Request routing gossip messages from a peer for a list of channels identified by
+ /// their short_channel_ids.
+ SendShortIdsQuery {
+ /// The node_id of this message recipient
+ node_id: PublicKey,
+ /// The query_short_channel_ids which should be sent.
+ msg: msgs::QueryShortChannelIds,
+ },
+ /// Sends a reply to a channel range query. This may be one of several SendReplyChannelRange events
+ /// emitted during processing of the query.
+ SendReplyChannelRange {
+ /// The node_id of this message recipient
+ node_id: PublicKey,
+ /// The reply_channel_range which should be sent.
+ msg: msgs::ReplyChannelRange,
+ },
+ /// Sends a timestamp filter for inbound gossip. This should be sent on each new connection to
+ /// enable receiving gossip messages from the peer.
+ SendGossipTimestampFilter {
+ /// The node_id of this message recipient
+ node_id: PublicKey,
+ /// The gossip_timestamp_filter which should be sent.
+ msg: msgs::GossipTimestampFilter,
+ },
}
/// A trait indicating an object may generate message send events
fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent>;
}
-/// A trait indicating an object may generate events
+/// A trait indicating an object may generate events.
+///
+/// Events are processed by passing an [`EventHandler`] to [`process_pending_events`].
+///
+/// # Requirements
+///
+/// See [`process_pending_events`] for requirements around event processing.
+///
+/// When using this trait, [`process_pending_events`] will call [`handle_event`] for each pending
+/// event since the last invocation. The handler must either act upon the event immediately
+/// or preserve it for later handling.
+///
+/// Note, handlers may call back into the provider and thus deadlocking must be avoided. Be sure to
+/// consult the provider's documentation on the implication of processing events and how a handler
+/// may safely use the provider (e.g., see [`ChannelManager::process_pending_events`] and
+/// [`ChainMonitor::process_pending_events`]).
+///
+/// (C-not implementable) As there is likely no reason for a user to implement this trait on their
+/// own type(s).
+///
+/// [`process_pending_events`]: Self::process_pending_events
+/// [`handle_event`]: EventHandler::handle_event
+/// [`ChannelManager::process_pending_events`]: crate::ln::channelmanager::ChannelManager#method.process_pending_events
+/// [`ChainMonitor::process_pending_events`]: crate::chain::chainmonitor::ChainMonitor#method.process_pending_events
pub trait EventsProvider {
- /// Gets the list of pending events which were generated by previous actions, clearing the list
- /// in the process.
- fn get_and_clear_pending_events(&self) -> Vec<Event>;
+ /// Processes any events generated since the last call using the given event handler.
+ ///
+ /// Subsequent calls must only process new events. However, handlers must be capable of handling
+ /// duplicate events across process restarts. This may occur if the provider was recovered from
+ /// an old state (i.e., it hadn't been successfully persisted after processing pending events).
+ fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler;
+}
+
+/// A trait implemented for objects handling events from [`EventsProvider`].
+pub trait EventHandler {
+ /// Handles the given [`Event`].
+ ///
+ /// See [`EventsProvider`] for details that must be considered when implementing this method.
+ fn handle_event(&self, event: &Event);
+}
+
+impl<F> EventHandler for F where F: Fn(&Event) {
+ fn handle_event(&self, event: &Event) {
+ self(event)
+ }
+}
+
+impl<T: EventHandler> EventHandler for Arc<T> {
+ fn handle_event(&self, event: &Event) {
+ self.deref().handle_event(event)
+ }
}