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