github.com/lzy4123/fabric@v2.1.1+incompatible/common/ledger/blockledger/ledger.go (about)

     1  /*
     2  Copyright IBM Corp. All Rights Reserved.
     3  
     4  SPDX-License-Identifier: Apache-2.0
     5  */
     6  
     7  package blockledger
     8  
     9  import (
    10  	cb "github.com/hyperledger/fabric-protos-go/common"
    11  	ab "github.com/hyperledger/fabric-protos-go/orderer"
    12  )
    13  
    14  // Factory retrieves or creates new ledgers by channelID
    15  type Factory interface {
    16  	// GetOrCreate gets an existing ledger (if it exists)
    17  	// or creates it if it does not
    18  	GetOrCreate(channelID string) (ReadWriter, error)
    19  
    20  	// ChannelIDs returns the channel IDs the Factory is aware of
    21  	ChannelIDs() []string
    22  
    23  	// Close releases all resources acquired by the factory
    24  	Close()
    25  }
    26  
    27  // Iterator is useful for a chain Reader to stream blocks as they are created
    28  type Iterator interface {
    29  	// Next blocks until there is a new block available, or returns an error if
    30  	// the next block is no longer retrievable
    31  	Next() (*cb.Block, cb.Status)
    32  	// Close releases resources acquired by the Iterator
    33  	Close()
    34  }
    35  
    36  // Reader allows the caller to inspect the ledger
    37  type Reader interface {
    38  	// Iterator returns an Iterator, as specified by an ab.SeekInfo message, and
    39  	// its starting block number
    40  	Iterator(startType *ab.SeekPosition) (Iterator, uint64)
    41  	// Height returns the number of blocks on the ledger
    42  	Height() uint64
    43  }
    44  
    45  // Writer allows the caller to modify the ledger
    46  type Writer interface {
    47  	// Append a new block to the ledger
    48  	Append(block *cb.Block) error
    49  }
    50  
    51  // ReadWriter encapsulates the read/write functions of the ledger
    52  type ReadWriter interface {
    53  	Reader
    54  	Writer
    55  }