github.com/tenywen/fabric@v1.0.0-beta.0.20170620030522-a5b1ed380643/orderer/ledger/file/impl.go (about)

     1  /*
     2  Copyright IBM Corp. 2016 All Rights Reserved.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8                   http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package fileledger
    18  
    19  import (
    20  	"github.com/hyperledger/fabric/common/ledger/blkstorage"
    21  	ledger "github.com/hyperledger/fabric/orderer/ledger"
    22  	cb "github.com/hyperledger/fabric/protos/common"
    23  	ab "github.com/hyperledger/fabric/protos/orderer"
    24  	"github.com/op/go-logging"
    25  )
    26  
    27  var logger = logging.MustGetLogger("orderer/fileledger")
    28  var closedChan chan struct{}
    29  
    30  func init() {
    31  	closedChan = make(chan struct{})
    32  	close(closedChan)
    33  }
    34  
    35  type fileLedger struct {
    36  	blockStore blkstorage.BlockStore
    37  	signal     chan struct{}
    38  }
    39  
    40  type fileLedgerIterator struct {
    41  	ledger      *fileLedger
    42  	blockNumber uint64
    43  }
    44  
    45  // Next blocks until there is a new block available, or returns an error if the
    46  // next block is no longer retrievable
    47  func (i *fileLedgerIterator) Next() (*cb.Block, cb.Status) {
    48  	for {
    49  		if i.blockNumber < i.ledger.Height() {
    50  			block, err := i.ledger.blockStore.RetrieveBlockByNumber(i.blockNumber)
    51  			if err != nil {
    52  				return nil, cb.Status_SERVICE_UNAVAILABLE
    53  			}
    54  			i.blockNumber++
    55  			return block, cb.Status_SUCCESS
    56  		}
    57  		<-i.ledger.signal
    58  	}
    59  }
    60  
    61  // ReadyChan supplies a channel which will block until Next will not block
    62  func (i *fileLedgerIterator) ReadyChan() <-chan struct{} {
    63  	signal := i.ledger.signal
    64  	if i.blockNumber > i.ledger.Height()-1 {
    65  		return signal
    66  	}
    67  	return closedChan
    68  }
    69  
    70  // Iterator returns an Iterator, as specified by a cb.SeekInfo message, and its
    71  // starting block number
    72  func (fl *fileLedger) Iterator(startPosition *ab.SeekPosition) (ledger.Iterator, uint64) {
    73  	switch start := startPosition.Type.(type) {
    74  	case *ab.SeekPosition_Oldest:
    75  		return &fileLedgerIterator{ledger: fl, blockNumber: 0}, 0
    76  	case *ab.SeekPosition_Newest:
    77  		info, err := fl.blockStore.GetBlockchainInfo()
    78  		if err != nil {
    79  			logger.Panic(err)
    80  		}
    81  		newestBlockNumber := info.Height - 1
    82  		return &fileLedgerIterator{ledger: fl, blockNumber: newestBlockNumber}, newestBlockNumber
    83  	case *ab.SeekPosition_Specified:
    84  		height := fl.Height()
    85  		if start.Specified.Number > height {
    86  			return &ledger.NotFoundErrorIterator{}, 0
    87  		}
    88  		return &fileLedgerIterator{ledger: fl, blockNumber: start.Specified.Number}, start.Specified.Number
    89  	}
    90  	// This line should be unreachable, but the compiler requires it
    91  	return &ledger.NotFoundErrorIterator{}, 0
    92  }
    93  
    94  // Height returns the number of blocks on the ledger
    95  func (fl *fileLedger) Height() uint64 {
    96  	info, err := fl.blockStore.GetBlockchainInfo()
    97  	if err != nil {
    98  		logger.Panic(err)
    99  	}
   100  	return info.Height
   101  }
   102  
   103  // Append a new block to the ledger
   104  func (fl *fileLedger) Append(block *cb.Block) error {
   105  	err := fl.blockStore.AddBlock(block)
   106  	if err == nil {
   107  		close(fl.signal)
   108  		fl.signal = make(chan struct{})
   109  	}
   110  	return err
   111  }