92 lines
2.1 KiB
Go
92 lines
2.1 KiB
Go
// Package cache implements the Fs cache
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package cache
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import (
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"sync"
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"time"
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"github.com/ncw/rclone/fs"
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)
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var (
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fsCacheMu sync.Mutex
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fsCache = map[string]*cacheEntry{}
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fsNewFs = fs.NewFs // for tests
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expireRunning = false
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cacheExpireDuration = 300 * time.Second // expire the cache entry when it is older than this
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cacheExpireInterval = 60 * time.Second // interval to run the cache expire
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)
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type cacheEntry struct {
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f fs.Fs // cached f
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err error // nil or fs.ErrorIsFile
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fsString string // remote string
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lastUsed time.Time // time used for expiry
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}
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// Get gets a fs.Fs named fsString either from the cache or creates it afresh
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func Get(fsString string) (f fs.Fs, err error) {
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fsCacheMu.Lock()
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defer fsCacheMu.Unlock()
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entry, ok := fsCache[fsString]
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if !ok {
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f, err = fsNewFs(fsString)
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if err != nil && err != fs.ErrorIsFile {
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return f, err
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}
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entry = &cacheEntry{
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f: f,
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fsString: fsString,
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err: err,
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}
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fsCache[fsString] = entry
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}
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entry.lastUsed = time.Now()
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if !expireRunning {
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time.AfterFunc(cacheExpireInterval, cacheExpire)
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expireRunning = true
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}
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return entry.f, entry.err
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}
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// Put puts an fs.Fs named fsString into the cache
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func Put(fsString string, f fs.Fs) {
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fsCacheMu.Lock()
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defer fsCacheMu.Unlock()
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fsCache[fsString] = &cacheEntry{
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f: f,
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fsString: fsString,
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lastUsed: time.Now(),
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}
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if !expireRunning {
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time.AfterFunc(cacheExpireInterval, cacheExpire)
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expireRunning = true
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}
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}
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// cacheExpire expires any entries that haven't been used recently
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func cacheExpire() {
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fsCacheMu.Lock()
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defer fsCacheMu.Unlock()
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now := time.Now()
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for fsString, entry := range fsCache {
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if now.Sub(entry.lastUsed) > cacheExpireDuration {
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delete(fsCache, fsString)
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}
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}
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if len(fsCache) != 0 {
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time.AfterFunc(cacheExpireInterval, cacheExpire)
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expireRunning = true
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} else {
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expireRunning = false
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}
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}
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// Clear removes everything from the cahce
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func Clear() {
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fsCacheMu.Lock()
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for k := range fsCache {
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delete(fsCache, k)
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}
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fsCacheMu.Unlock()
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}
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