func openSegment(path string) *segment {
log.Info("Opening segment file %s", path)
seg := &segment{
nextSegments: make([]*segment, 0),
prevSegments: make([]*segment, 0),
writable: false,
lock: new(sync.Mutex),
}
var err os.Error
stat, err := os.Stat(path)
if stat == nil || err != nil {
log.Fatal("Couldn't stat segment file %s: %s", path, err)
}
var from, to Token
_, err = fmt.Sscanf(stat.Name, "%016X_%04X_%04X.seg", &seg.positionStart, &from, &to)
if err != nil {
log.Fatal("Couldn't read segment file name %s: %s", path, err)
}
seg.tokens = TokenRange{from, to}
seg.fd, err = os.Open(path)
if err != nil {
log.Fatal("Couldn't open segment %s: %s", path, err)
}
seg.typedFd = typedio.NewReadWriter(seg.fd)
seg.positionEnd = seg.positionStart + uint64(stat.Size)
return seg
}
func createSegment(dataDir string, token_from, token_to Token, position uint64) *segment {
seg := &segment{
nextSegments: make([]*segment, 0),
prevSegments: make([]*segment, 0),
tokens: TokenRange{token_from, token_to},
positionStart: position,
positionEnd: position,
lock: new(sync.Mutex),
}
var err os.Error
filePath := fmt.Sprintf("%s/%016X_%04X_%04X.seg", dataDir, position, token_from, token_to)
seg.fd, err = os.Create(filePath)
if err != nil {
log.Fatal("Couldn't open segment %s: %s", filePath, err)
}
seg.typedFd = typedio.NewReadWriter(seg.fd)
seg.writable = true
seg.buf = bufio.NewWriter(seg.fd)
seg.typedBuf = typedio.NewWriter(seg.buf)
return seg
}
func New(directory string) *CommitLog {
cl := new(CommitLog)
cl.mutations = make(map[byte]mutationInfo)
cl.mutationsType = make(map[reflect.Type]mutationInfo)
cl.fdMutex = new(sync.Mutex)
// check if directory exists, create it otherwize
dir, err := os.Stat(directory)
if dir == nil || !dir.IsDirectory() {
os.Mkdir(directory, 0777)
}
// check if log file exists and its at least the header size
path := directory + "000.log"
dir, err = os.Stat(path)
existed := false
if dir != nil && err == nil && dir.IsRegular() && dir.Size > HEADER_END {
existed = true
}
// open the log
flag := os.O_RDWR | os.O_CREATE
cl.fd, err = os.OpenFile(path, flag, 0777)
if err != nil {
log.Fatal("CommitLog: Cannot open commit log file %s: %s", path, err)
}
cl.typedFd = typedio.NewReadWriter(cl.fd)
// if commit log existed, read header
if existed {
cl.writePtr, _ = cl.typedFd.ReadInt64()
cl.commitPtr, _ = cl.typedFd.ReadInt64()
} else {
// else, write header
cl.writePtr = HEADER_END
cl.commitPtr = HEADER_END
cl.typedFd.WriteInt64(cl.writePtr)
cl.typedFd.WriteInt64(cl.commitPtr)
}
return cl
}
func New() *Buffer {
r := new(Buffer)
r.ReadWriter = typedio.NewReadWriter(r)
return r
}