func writeGetResponse(w *bufio.Writer, key []byte, item *ybc.Item, shouldWriteCasid bool, scratchBuf *[]byte) bool {
var casid uint64
var buf [casidSize + flagsSize]byte
n, err := item.Read(buf[:])
if err != nil {
log.Printf("error when reading item metadata: [%s]", err)
return false
}
if n != len(buf) {
log.Printf("Unexpected result returned from ybc.Item.Read(): %d. Expected %d", n, len(buf))
return false
}
if shouldWriteCasid {
casid = binary.LittleEndian.Uint64(buf[:])
}
flags := binary.LittleEndian.Uint32(buf[casidSize:])
size := item.Available()
if !writeStr(w, strValue) || !writeStr(w, key) || !writeWs(w) ||
!writeUint32(w, flags, scratchBuf) || !writeWs(w) ||
!writeInt(w, size, scratchBuf) {
return false
}
if shouldWriteCasid {
if !writeWs(w) || !writeUint64(w, casid, scratchBuf) {
return false
}
}
return writeStr(w, strCrLf) && writeItem(w, item, size)
}
func writeItem(w *bufio.Writer, item *ybc.Item, size int) bool {
n, err := item.WriteTo(w)
if err != nil {
log.Printf("Error when writing payload with size=[%d] to output stream: [%s]", size, err)
return false
}
if n != int64(size) {
log.Printf("Invalid length of payload=[%d] written to output stream. Expected [%d]", n, size)
return false
}
return writeCrLf(w)
}
func setItemValue(it *ybc.Item, item *Item) error {
size := it.Available()
item.Value = make([]byte, size)
n, err := it.Read(item.Value)
if err != nil {
log.Fatalf("Unexpected error in Item.Read(size=%d): [%s]", size, err)
}
if n != size {
log.Fatalf("Unexpected number of bytes read in Item.Read(size=%d): %d", size, n)
}
return nil
}
func updateLocalItem(cache ybc.Cacher, it *ybc.Item, key []byte, casid uint64, flags, validateTtl uint32) {
size := it.Available()
defer it.Seek(-int64(size), 2)
txn := writeItemMetadata(cache, key, size, casid, flags, validateTtl)
if txn == nil {
return
}
defer txn.Commit()
n, err := txn.ReadFrom(it)
if err != nil {
log.Fatalf("Unexpected error in SetTxn.ReadFrom(size=%d): [%s]", size, err)
}
if n != int64(size) {
log.Fatalf("Unexpected number of bytes copied in SetTxn.ReadFrom(size=%d): %d", size, n)
}
}
func writeCgetResponse(w *bufio.Writer, etag uint64, item *ybc.Item, scratchBuf *[]byte) bool {
var validateTtl, flags uint32
if err := binaryRead(item, &validateTtl, "validateTtl"); err != nil {
return false
}
if err := binaryRead(item, &flags, "flags"); err != nil {
return false
}
size := item.Available()
expiration := item.Ttl()
return writeStr(w, strValue) && writeInt(w, size, scratchBuf) && writeWs(w) &&
writeUint32(w, flags, scratchBuf) && writeWs(w) &&
writeExpiration(w, expiration, scratchBuf) && writeWs(w) &&
writeUint64(w, etag, scratchBuf) && writeWs(w) &&
writeUint32(w, validateTtl, scratchBuf) && writeCrLf(w) &&
writeItem(w, item, size)
}
func readItemMetadata(it *ybc.Item) (casid uint64, flags uint32, validateExpiration time.Time, validateTtl uint32, ok bool) {
var buf [metadataSize]byte
n, err := it.Read(buf[:])
if err != nil {
log.Printf("Cannot read metadata for cached item: [%s]", err)
return
}
if n != len(buf) {
log.Printf("Unexpected result returned from ybc.Item.Read(): %d. Expected %d", n, len(buf))
return
}
casid = binary.LittleEndian.Uint64(buf[:])
flags = binary.LittleEndian.Uint32(buf[casidSize:])
validateTtl = binary.LittleEndian.Uint32(buf[casidSize+flagsSize:])
validateExpiration64 := binary.LittleEndian.Uint64(buf[casidSize+flagsSize+validateTtlSize:])
validateExpiration = time.Unix(0, int64(validateExpiration64))
ok = true
return
}
func writeGetResponse(w *bufio.Writer, key []byte, item *ybc.Item, cas bool, scratchBuf *[]byte) bool {
var flags uint32
if err := binaryRead(item, &flags, "flags"); err != nil {
return false
}
size := item.Available()
if !writeStr(w, strValue) || !writeStr(w, key) || !writeWs(w) ||
!writeUint32(w, flags, scratchBuf) || !writeWs(w) ||
!writeInt(w, size, scratchBuf) {
return false
}
if cas {
if !writeWs(w) || !writeZero(w) {
return false
}
}
return writeCrLf(w) && writeItem(w, item, size)
}
func checkAndUpdateCasid(item *ybc.Item, casid *uint64) (isModified, ok bool) {
casidOld := *casid
var buf [casidSize]byte
n, err := item.Read(buf[:])
if err != nil {
log.Printf("Cannod read casid from item: [%s]", err)
return
}
if n != len(buf) {
log.Printf("Unexpected result returned from ybc.Item.Read(): %d. Expected %d", n, len(buf))
return
}
*casid = binary.LittleEndian.Uint64(buf[:])
if _, err := item.Seek(-casidSize, 1); err != nil {
log.Fatalf("Unexpected error returned from ybc.Item.Seek(%d, 1): [%s]", -casidSize, err)
}
isModified = (casidOld != *casid)
ok = true
return
}
func updateLocalItem(cache ybc.Cacher, it *ybc.Item, item *Item, etag uint64, validateTtl uint32) {
size := it.Available()
offset := it.Size() - size
defer it.Seek(int64(offset), 0)
txn := writeItemMetadata(cache, item.Key, size, it.Ttl(), etag, validateTtl, item.Flags)
if txn == nil {
return
}
defer txn.Commit()
n, err := txn.ReadFrom(it)
if err != nil {
log.Fatalf("Unexpected error in SetTxn.ReadFrom(size=%d): [%s]", size, err)
}
if n != int64(size) {
log.Fatalf("Unexpected number of bytes copied in SetTxn.ReadFrom(size=%d): %d", size, n)
}
}