lnd.xprv/contractcourt/contract_resolvers.go

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package contractcourt
import (
"encoding/binary"
"errors"
"io"
)
var (
endian = binary.BigEndian
)
const (
// sweepConfTarget is the default number of blocks that we'll use as a
// confirmation target when sweeping.
sweepConfTarget = 6
)
// ContractResolver is an interface which packages a state machine which is
// able to carry out the necessary steps required to fully resolve a Bitcoin
// contract on-chain. Resolvers are fully encodable to ensure callers are able
// to persist them properly. A resolver may produce another resolver in the
// case that claiming an HTLC is a multi-stage process. In this case, we may
// partially resolve the contract, then persist, and set up for an additional
// resolution.
type ContractResolver interface {
// ResolverKey returns an identifier which should be globally unique
// for this particular resolver within the chain the original contract
// resides within.
ResolverKey() []byte
// Resolve instructs the contract resolver to resolve the output
// on-chain. Once the output has been *fully* resolved, the function
// should return immediately with a nil ContractResolver value for the
// first return value. In the case that the contract requires further
// resolution, then another resolve is returned.
//
// NOTE: This function MUST be run as a goroutine.
Resolve() (ContractResolver, error)
// IsResolved returns true if the stored state in the resolve is fully
// resolved. In this case the target output can be forgotten.
IsResolved() bool
// Encode writes an encoded version of the ContractResolver into the
// passed Writer.
Encode(w io.Writer) error
// Decode attempts to decode an encoded ContractResolver from the
// passed Reader instance, returning an active ContractResolver
// instance.
Decode(r io.Reader) error
// AttachResolverKit should be called once a resolved is successfully
// decoded from its stored format. This struct delivers a generic tool
// kit that resolvers need to complete their duty.
AttachResolverKit(ResolverKit)
// Stop signals the resolver to cancel any current resolution
// processes, and suspend.
Stop()
}
// reportingContractResolver is a ContractResolver that also exposes a report on
// the resolution state of the contract.
type reportingContractResolver interface {
ContractResolver
report() *ContractReport
}
// ResolverKit is meant to be used as a mix-in struct to be embedded within a
// given ContractResolver implementation. It contains all the items that a
// resolver requires to carry out its duties.
type ResolverKit struct {
// ChannelArbitratorConfig contains all the interfaces and closures
// required for the resolver to interact with outside sub-systems.
ChannelArbitratorConfig
// Checkpoint allows a resolver to check point its state. This function
// should write the state of the resolver to persistent storage, and
// return a non-nil error upon success.
Checkpoint func(ContractResolver) error
Quit chan struct{}
}
var (
// errResolverShuttingDown is returned when the resolver stops
// progressing because it received the quit signal.
errResolverShuttingDown = errors.New("resolver shutting down")
)