seaweedfs/weed/filesys/page_writer_pattern.go

42 lines
915 B
Go

package filesys
type WriterPattern struct {
isStreaming bool
lastWriteOffset int64
chunkSize int64
fileName string
}
// For streaming write: only cache the first chunk
// For random write: fall back to temp file approach
// writes can only change from streaming mode to non-streaming mode
func NewWriterPattern(fileName string, chunkSize int64) *WriterPattern {
return &WriterPattern{
isStreaming: true,
lastWriteOffset: -1,
chunkSize: chunkSize,
fileName: fileName,
}
}
func (rp *WriterPattern) MonitorWriteAt(offset int64, size int) {
if rp.lastWriteOffset > offset {
rp.isStreaming = false
}
if rp.lastWriteOffset == -1 {
if offset != 0 {
rp.isStreaming = false
}
}
rp.lastWriteOffset = offset
}
func (rp *WriterPattern) IsStreamingMode() bool {
return rp.isStreaming
}
func (rp *WriterPattern) IsRandomMode() bool {
return !rp.isStreaming
}