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// +build !plan9
package cache
import (
"strconv"
"strings"
"time"
cache "github.com/patrickmn/go-cache"
"github.com/pkg/errors"
"github.com/rclone/rclone/fs"
)
// Memory is a wrapper of transient storage for a go-cache store
type Memory struct {
db *cache.Cache
}
// NewMemory builds this cache storage
// defaultExpiration will set the expiry time of chunks in this storage
func NewMemory(defaultExpiration time.Duration) *Memory {
mem := &Memory{}
err := mem.Connect(defaultExpiration)
if err != nil {
fs.Errorf("cache", "can't open ram connection: %v", err)
}
return mem
}
// Connect will create a connection for the storage
func (m *Memory) Connect(defaultExpiration time.Duration) error {
m.db = cache.New(defaultExpiration, -1)
return nil
}
// HasChunk confirms the existence of a single chunk of an object
func (m *Memory) HasChunk(cachedObject *Object, offset int64) bool {
key := cachedObject.abs() + "-" + strconv.FormatInt(offset, 10)
_, found := m.db.Get(key)
return found
}
// GetChunk will retrieve a single chunk which belongs to a cached object or an error if it doesn't find it
func (m *Memory) GetChunk(cachedObject *Object, offset int64) ([]byte, error) {
key := cachedObject.abs() + "-" + strconv.FormatInt(offset, 10)
var data []byte
if x, found := m.db.Get(key); found {
data = x.([]byte)
return data, nil
}
return nil, errors.Errorf("couldn't get cached object data at offset %v", offset)
}
// AddChunk adds a new chunk of a cached object
func (m *Memory) AddChunk(fp string, data []byte, offset int64) error {
return m.AddChunkAhead(fp, data, offset, time.Second)
}
// AddChunkAhead adds a new chunk of a cached object
func (m *Memory) AddChunkAhead(fp string, data []byte, offset int64, t time.Duration) error {
key := fp + "-" + strconv.FormatInt(offset, 10)
m.db.Set(key, data, cache.DefaultExpiration)
return nil
}
// CleanChunksByAge will cleanup on a cron basis
func (m *Memory) CleanChunksByAge(chunkAge time.Duration) {
m.db.DeleteExpired()
}
// CleanChunksByNeed will cleanup chunks after the FS passes a specific chunk
func (m *Memory) CleanChunksByNeed(offset int64) {
var items map[string]cache.Item
items = m.db.Items()
for key := range items {
sepIdx := strings.LastIndex(key, "-")
keyOffset, err := strconv.ParseInt(key[sepIdx+1:], 10, 64)
if err != nil {
fs.Errorf("cache", "couldn't parse offset entry %v", key)
continue
}
if keyOffset < offset {
m.db.Delete(key)
}
}
}
// CleanChunksBySize will cleanup chunks after the total size passes a certain point
func (m *Memory) CleanChunksBySize(maxSize int64) {
// NOOP
}
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