client

type ConsensusCheckpointFunc ¶

type ConsensusCheckpointFunc func(ctx context.Context, logSigV note.Verifier, origin string) (*log.Checkpoint, []byte, *note.Note, error)

ConsensusCheckpointFunc is a function which returns the largest checkpoint known which is signed by logSigV and satisfies some consensus algorithm.

This is intended to provide a hook for adding a consensus view of a log, e.g. via witnessing.

func UnilateralConsensus(f Fetcher) ConsensusCheckpointFunc

type ErrInconsistency ¶

type ErrInconsistency struct {
	SmallerRaw []byte
	LargerRaw  []byte
	Proof      [][]byte

	Wrapped error
}

ErrInconsistency should be returned when there has been an error proving consistency between log states. The raw log state representations are included as-returned by the target log, this ensures that evidence of inconsistent log updates are available to the caller of the method(s) returning this error.

func (e ErrInconsistency) Error() string

func (e ErrInconsistency) Unwrap() error

type Fetcher ¶

type Fetcher func(ctx context.Context, path string) ([]byte, error)

Fetcher is the signature of a function which can retrieve arbitrary files from a log's data storage, via whatever appropriate mechanism. The path parameter is relative to the root of the log storage.

Note that the implementation of this MUST return (either directly or wrapped) an os.ErrIsNotExit when the file referenced by path does not exist, e.g. a HTTP based implementation MUST return this error when it receives a 404 StatusCode.

type GetTileFunc ¶

type GetTileFunc func(ctx context.Context, level, index uint64) (*api.Tile, error)

GetTileFunc is the signature of a function which knows how to fetch a specific tile.

type LogStateTracker ¶

type LogStateTracker struct {
	Hasher  merkle.LogHasher
	Fetcher Fetcher
	// Origin is the expected first line of checkpoints from the log.
	Origin              string
	ConsensusCheckpoint ConsensusCheckpointFunc

	// LatestConsistentRaw holds the raw bytes of the latest proven-consistent
	// LogState seen by this tracker.
	LatestConsistentRaw []byte
	// LatestConsistent is the deserialised form of LatestConsistentRaw
	LatestConsistent log.Checkpoint
	// The note with signatures and other metadata about the checkpoint
	CheckpointNote *note.Note
	// ProofBuilder for building proofs at LatestConsistent checkpoint.
	ProofBuilder *ProofBuilder

	CpSigVerifier note.Verifier
}

LogStateTracker represents a client-side view of a target log's state. This tracker handles verification that updates to the tracked log state are consistent with previously seen states.

func NewLogStateTracker(ctx context.Context, f Fetcher, h merkle.LogHasher, checkpointRaw []byte, nV note.Verifier, origin string, cc ConsensusCheckpointFunc) (LogStateTracker, error)

func (lst *LogStateTracker) Update(ctx context.Context) ([]byte, [][]byte, []byte, error)

type ProofBuilder ¶

type ProofBuilder struct {
	// contains filtered or unexported fields
}

ProofBuilder knows how to build inclusion and consistency proofs from tiles. Since the tiles commit only to immutable nodes, the job of building proofs is slightly more complex as proofs can touch "ephemeral" nodes, so these need to be synthesized.

func NewProofBuilder(ctx context.Context, cp log.Checkpoint, h compact.HashFn, f Fetcher) (*ProofBuilder, error)

func (pb *ProofBuilder) ConsistencyProof(ctx context.Context, smaller, larger uint64) ([][]byte, error)

func (pb *ProofBuilder) InclusionProof(ctx context.Context, index uint64) ([][]byte, error)