Move all backends into backend directory

backend/cache/storage_memory.go

@@ -0,0 +1,100 @@
+// +build !plan9,go1.7
+
+package cache
+
+import (
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/ncw/rclone/fs"
+	"github.com/patrickmn/go-cache"
+	"github.com/pkg/errors"
+)
+
+// Memory is a wrapper of transient storage for a go-cache store
+type Memory struct {
+	ChunkStorage
+
+	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
+}