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

     1  /*
     2  Copyright IBM Corp. 2017 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 ramledger
    18  
    19  import (
    20  	"sync"
    21  
    22  	"github.com/hyperledger/fabric/orderer/ledger"
    23  	cb "github.com/hyperledger/fabric/protos/common"
    24  )
    25  
    26  type ramLedgerFactory struct {
    27  	maxSize int
    28  	ledgers map[string]ledger.ReadWriter
    29  	mutex   sync.Mutex
    30  }
    31  
    32  // GetOrCreate gets an existing ledger (if it exists) or creates it if it does not
    33  func (rlf *ramLedgerFactory) GetOrCreate(chainID string) (ledger.ReadWriter, error) {
    34  	rlf.mutex.Lock()
    35  	defer rlf.mutex.Unlock()
    36  
    37  	key := chainID
    38  
    39  	l, ok := rlf.ledgers[key]
    40  	if ok {
    41  		return l, nil
    42  	}
    43  
    44  	ch := newChain(rlf.maxSize)
    45  	rlf.ledgers[key] = ch
    46  	return ch, nil
    47  }
    48  
    49  // newChain creates a new chain backed by a RAM ledger
    50  func newChain(maxSize int) ledger.ReadWriter {
    51  	preGenesis := &cb.Block{
    52  		Header: &cb.BlockHeader{
    53  			Number: ^uint64(0),
    54  		},
    55  	}
    56  
    57  	rl := &ramLedger{
    58  		maxSize: maxSize,
    59  		size:    1,
    60  		oldest: &simpleList{
    61  			signal: make(chan struct{}),
    62  			block:  preGenesis,
    63  		},
    64  	}
    65  	rl.newest = rl.oldest
    66  	return rl
    67  }
    68  
    69  // ChainIDs returns the chain IDs the factory is aware of
    70  func (rlf *ramLedgerFactory) ChainIDs() []string {
    71  	rlf.mutex.Lock()
    72  	defer rlf.mutex.Unlock()
    73  	ids := make([]string, len(rlf.ledgers))
    74  
    75  	i := 0
    76  	for key := range rlf.ledgers {
    77  		ids[i] = key
    78  		i++
    79  	}
    80  
    81  	return ids
    82  }
    83  
    84  // Close is a no-op for the RAM ledger
    85  func (rlf *ramLedgerFactory) Close() {
    86  	return // nothing to do
    87  }
    88  
    89  // New creates a new ledger factory
    90  func New(maxSize int) ledger.Factory {
    91  	rlf := &ramLedgerFactory{
    92  		maxSize: maxSize,
    93  		ledgers: make(map[string]ledger.ReadWriter),
    94  	}
    95  
    96  	return rlf
    97  }