github.com/linapex/ethereum-go-chinese@v0.0.0-20190316121929-f8b7a73c3fa1/swarm/storage/memstore.go (about)

     1  
     2  //<developer>
     3  //    <name>linapex 曹一峰</name>
     4  //    <email>linapex@163.com</email>
     5  //    <wx>superexc</wx>
     6  //    <qqgroup>128148617</qqgroup>
     7  //    <url>https://jsq.ink</url>
     8  //    <role>pku engineer</role>
     9  //    <date>2019-03-16 19:16:45</date>
    10  //</624450120301154304>
    11  
    12  
    13  //包块哈希的内存存储层
    14  
    15  package storage
    16  
    17  import (
    18  	"context"
    19  
    20  	lru "github.com/hashicorp/golang-lru"
    21  )
    22  
    23  type MemStore struct {
    24  	cache    *lru.Cache
    25  	disabled bool
    26  }
    27  
    28  //newmemstore正在实例化memstore缓存，以保留所有经常请求的缓存
    29  //“cache”lru缓存中的块。
    30  func NewMemStore(params *StoreParams, _ *LDBStore) (m *MemStore) {
    31  	if params.CacheCapacity == 0 {
    32  		return &MemStore{
    33  			disabled: true,
    34  		}
    35  	}
    36  
    37  	c, err := lru.New(int(params.CacheCapacity))
    38  	if err != nil {
    39  		panic(err)
    40  	}
    41  
    42  	return &MemStore{
    43  		cache: c,
    44  	}
    45  }
    46  
    47  func (m *MemStore) Get(_ context.Context, addr Address) (Chunk, error) {
    48  	if m.disabled {
    49  		return nil, ErrChunkNotFound
    50  	}
    51  
    52  	c, ok := m.cache.Get(string(addr))
    53  	if !ok {
    54  		return nil, ErrChunkNotFound
    55  	}
    56  	return c.(Chunk), nil
    57  }
    58  
    59  func (m *MemStore) Put(_ context.Context, c Chunk) error {
    60  	if m.disabled {
    61  		return nil
    62  	}
    63  
    64  	m.cache.Add(string(c.Address()), c)
    65  	return nil
    66  }
    67  
    68  func (m *MemStore) setCapacity(n int) {
    69  	if n <= 0 {
    70  		m.disabled = true
    71  	} else {
    72  		c, err := lru.New(n)
    73  		if err != nil {
    74  			panic(err)
    75  		}
    76  
    77  		*m = MemStore{
    78  			cache: c,
    79  		}
    80  	}
    81  }
    82  
    83  func (s *MemStore) Close() {}
    84