func (h *HANDLE) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
var chunkIdx, numChunks int64
var offInChunk, totalRead int
f := h.f
chunkSz := h.chunkSz
// TODO: Use the masks!!
chunkIdx = req.Offset / int64(chunkSz)
offInChunk = int(req.Offset - chunkIdx*int64(chunkSz))
numChunks = int64((req.Size + chunkSz - 1) / chunkSz)
if chunkIdx >= f.Entry.NumChunks || req.Size == 0 {
resp.Data = []byte{}
return nil
}
if chunkIdx+numChunks > f.Entry.NumChunks {
numChunks = f.Entry.NumChunks - chunkIdx
}
resp.Data = make([]byte, int(numChunks)*chunkSz)
remain := req.Size
totalRead = 0
for i := int64(0); i < numChunks; i++ {
n, err := readChunk(h, chunkIdx+i, resp.Data[totalRead:], offInChunk, remain)
if err != nil && err != io.EOF {
log.WithFields(log.Fields{
"File": f.cacheName,
"chunkIdx": chunkIdx,
"chunkSz": chunkSz,
"Error": err,
}).Error("Read: readChunk failed")
return err
}
offInChunk = 0
remain -= n
totalRead += n
if err == io.EOF {
break
}
}
resp.Data = resp.Data[:totalRead]
log.WithFields(log.Fields{
"Chunk Size": chunkSz,
"File": f.cacheName,
"Offset": req.Offset,
"Size": req.Size,
"Read": totalRead,
}).Debug("Read")
return nil
}
// HandleRead handles a read request assuming that data is the entire file content.
// It adjusts the amount returned in resp according to req.Offset and req.Size.
func HandleRead(req *fuse.ReadRequest, resp *fuse.ReadResponse, data []byte) {
if req.Offset >= int64(len(data)) {
data = nil
} else {
data = data[req.Offset:]
}
if len(data) > req.Size {
data = data[:req.Size]
}
n := copy(resp.Data[:req.Size], data)
resp.Data = resp.Data[:n]
}