func newSegmentMap() *segmentMap {
return &segmentMap{
entries: skiplist.NewCustomMap(func(l, r interface{}) bool {
return l.(uint64) > r.(uint64)
}),
}
}
// New returns a disk-backed WriteAheadLogger
func New(name string, dataPath string, segmentMaxBytes int64, syncTimeout time.Duration, logger logger) (WriteAheadLogger, error) {
var err error
w := &wal{
name: name,
dataPath: dataPath,
segmentMaxBytes: segmentMaxBytes,
exitChan: make(chan int),
syncTimeout: syncTimeout,
logger: logger,
version: 1,
// uint64 keyed skip-list with *reverse* ordering so that
// GetGreaterOrEqual actually returns LT | EQ
segmentList: skiplist.NewCustomMap(func(l, r interface{}) bool {
return l.(uint64) > r.(uint64)
}),
}
rwl := &rwLock{&w.metadataLock}
w.writeCond = sync.NewCond(rwl)
w.rollCond = sync.NewCond(rwl)
err = w.scanSegments()
if err != nil {
w.logf("ERROR: scanSegments - %s", err)
}
segment, err := w.openSegment(w.segmentNum, w.idx)
if err != nil {
return nil, err
}
w.segment = segment
w.segmentOffset = w.segment.offset
if w.syncTimeout > 0 {
go w.syncLoop()
}
return w, err
}