func CreateNextBlock(rl Reader, messages []*cb.Envelope) *cb.Block
CreateNextBlock provides a utility way to construct the next block from contents and metadata for a given ledger XXX This will need to be modified to accept marshaled envelopes
to accommodate non-deterministic marshaling
func GetBlock(rl Reader, index uint64) *cb.Block
GetBlock is a utility method for retrieving a single block
Factory retrieves or creates new ledgers by chainID
type Factory interface {
// GetOrCreate gets an existing ledger (if it exists)
// or creates it if it does not
GetOrCreate(chainID string) (ReadWriter, error)
// ChainIDs returns the chain IDs the Factory is aware of
ChainIDs() []string
// Close releases all resources acquired by the factory
Close()
}
Iterator is useful for a chain Reader to stream blocks as they are created
type Iterator interface {
// Next blocks until there is a new block available, or returns an error if
// the next block is no longer retrievable
Next() (*cb.Block, cb.Status)
// Close releases resources acquired by the Iterator
Close()
}
NotFoundErrorIterator simply always returns an error of cb.Status_NOT_FOUND, and is generally useful for implementations of the Reader interface
type NotFoundErrorIterator struct{}
func (nfei *NotFoundErrorIterator) Close()
Close does nothing
func (nfei *NotFoundErrorIterator) Next() (*cb.Block, cb.Status)
Next returns nil, cb.Status_NOT_FOUND
func (nfei *NotFoundErrorIterator) ReadyChan() <-chan struct{}
ReadyChan returns a closed channel
ReadWriter encapsulates the read/write functions of the ledger
type ReadWriter interface {
Reader
Writer
}
Reader allows the caller to inspect the ledger
type Reader interface {
// Iterator returns an Iterator, as specified by an ab.SeekInfo message, and
// its starting block number
Iterator(startType *ab.SeekPosition) (Iterator, uint64)
// Height returns the number of blocks on the ledger
Height() uint64
}
Writer allows the caller to modify the ledger
type Writer interface {
// Append a new block to the ledger
Append(block *cb.Block) error
}