lnd.xprv/routing/chainview/interface.go

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package chainview
import (
"github.com/roasbeef/btcd/chaincfg/chainhash"
"github.com/roasbeef/btcd/wire"
)
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// FilteredChainView represents a subscription to a certain subset of the
// UTXO set for a particular chain. This interface is useful from the point of
// view of maintaining an up-to-date channel graph for the Lightning Network.
// The subset of the UTXO to be subscribed is that of all the currently opened
// channels. Each time a channel is closed (the output is spent), a
// notification is to be sent allowing the graph to be pruned.
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//
// NOTE: As FilteredBlocks are generated, it is recommended that
// implementations reclaim the space occupied by newly spent outputs.
type FilteredChainView interface {
// FilteredBlocks returns the channel that filtered blocks are to be
// sent over. Each time a block is connected to the end of a main
// chain, and appropriate FilteredBlock which contains the transactions
// which mutate our watched UTXO set is to be returned. In case of a
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// UpdateFilter call with an updateHeight lower than the current best
// height, blocks with the updated filter will be resent, and must be
// handled by the receiver as an update to an already known block, NOT
// as a new block being connected to the chain.
FilteredBlocks() <-chan *FilteredBlock
// DisconnectedBlocks returns a receive only channel which will be sent
// upon with the empty filtered blocks of blocks which are disconnected
// from the main chain in the case of a re-org.
// NOTE: In case of a reorg, connected blocks will not be available to
// read from the FilteredBlocks() channel before all disconnected block
// have been received.
DisconnectedBlocks() <-chan *FilteredBlock
// UpdateFilter updates the UTXO filter which is to be consulted when
// creating FilteredBlocks to be sent to subscribed clients. This
// method is cumulative meaning repeated calls to this method should
// _expand_ the size of the UTXO sub-set currently being watched. If
// the set updateHeight is _lower_ than the best known height of the
// implementation, then the state should be rewound to ensure all
// relevant notifications are dispatched, meaning blocks with a height
// lower than the best known height might be sent over the
// FilteredBlocks() channel.
UpdateFilter(ops []wire.OutPoint, updateHeight uint32) error
// FilterBlock takes a block hash, and returns a FilteredBlocks which
// is the result of applying the current registered UTXO sub-set on the
// block corresponding to that block hash.
//
// TODO(roasbeef): make a version that does by height also?
FilterBlock(blockHash *chainhash.Hash) (*FilteredBlock, error)
// Start starts all goroutine necessary for the operation of the
// FilteredChainView implementation.
Start() error
// Stop stops all goroutines which we launched by the prior call to the
// Start method.
Stop() error
}
// FilteredBlock is a block which includes the transactions that modify the
// subscribed sub-set of the UTXO set registered to the current
// FilteredChainView concrete implementation.
type FilteredBlock struct {
// Hash is the hash of the newly filtered block.
Hash chainhash.Hash
// Height is the height of the newly filtered block.
Height uint32
// Transactions is the set of transactions which modify (spend) the
// subscribed UTXO subset.
Transactions []*wire.MsgTx
}