1 files changed, 113 insertions, 0 deletions
diff --git a/weed/util/chunk_cache/chunk_cache.go b/weed/util/chunk_cache/chunk_cache.go
new file mode 100644
index 000000000..e1d4b639f
--- /dev/null
+++ b/weed/util/chunk_cache/chunk_cache.go
@@ -0,0 +1,113 @@
+package chunk_cache
+
+import (
+	"sync"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+)
+
+const (
+	memCacheSizeLimit     = 1024 * 1024
+	onDiskCacheSizeLimit0 = memCacheSizeLimit
+	onDiskCacheSizeLimit1 = 4 * memCacheSizeLimit
+)
+
+// a global cache for recently accessed file chunks
+type ChunkCache struct {
+	memCache   *ChunkCacheInMemory
+	diskCaches []*OnDiskCacheLayer
+	sync.RWMutex
+}
+
+func NewChunkCache(maxEntries int64, dir string, diskSizeMB int64) *ChunkCache {
+
+	c := &ChunkCache{
+		memCache: NewChunkCacheInMemory(maxEntries),
+	}
+	c.diskCaches = make([]*OnDiskCacheLayer, 3)
+	c.diskCaches[0] = NewOnDiskCacheLayer(dir, "c0_1", diskSizeMB/4, 4)
+	c.diskCaches[1] = NewOnDiskCacheLayer(dir, "c1_4", diskSizeMB/4, 4)
+	c.diskCaches[2] = NewOnDiskCacheLayer(dir, "cache", diskSizeMB/2, 4)
+
+	return c
+}
+
+func (c *ChunkCache) GetChunk(fileId string, chunkSize uint64) (data []byte) {
+	if c == nil {
+		return
+	}
+
+	c.RLock()
+	defer c.RUnlock()
+
+	return c.doGetChunk(fileId, chunkSize)
+}
+
+func (c *ChunkCache) doGetChunk(fileId string, chunkSize uint64) (data []byte) {
+
+	if chunkSize < memCacheSizeLimit {
+		if data = c.memCache.GetChunk(fileId); data != nil {
+			return data
+		}
+	}
+
+	fid, err := needle.ParseFileIdFromString(fileId)
+	if err != nil {
+		glog.Errorf("failed to parse file id %s", fileId)
+		return nil
+	}
+
+	for _, diskCache := range c.diskCaches {
+		data := diskCache.getChunk(fid.Key)
+		if len(data) != 0 {
+			return data
+		}
+	}
+
+	return nil
+
+}
+
+func (c *ChunkCache) SetChunk(fileId string, data []byte) {
+	if c == nil {
+		return
+	}
+	c.Lock()
+	defer c.Unlock()
+
+	c.doSetChunk(fileId, data)
+}
+
+func (c *ChunkCache) doSetChunk(fileId string, data []byte) {
+
+	if len(data) < memCacheSizeLimit {
+		c.memCache.SetChunk(fileId, data)
+	}
+
+	fid, err := needle.ParseFileIdFromString(fileId)
+	if err != nil {
+		glog.Errorf("failed to parse file id %s", fileId)
+		return
+	}
+
+	if len(data) < onDiskCacheSizeLimit0 {
+		c.diskCaches[0].setChunk(fid.Key, data)
+	} else if len(data) < onDiskCacheSizeLimit1 {
+		c.diskCaches[1].setChunk(fid.Key, data)
+	} else {
+		c.diskCaches[2].setChunk(fid.Key, data)
+	}
+
+}
+
+func (c *ChunkCache) Shutdown() {
+	if c == nil {
+		return
+	}
+	c.Lock()
+	defer c.Unlock()
+	for _, diskCache := range c.diskCaches {
+		diskCache.shutdown()
+	}
+}