106 lines
2.6 KiB
Go
106 lines
2.6 KiB
Go
package oss
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import "io"
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// ProgressEventType defines transfer progress event type
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type ProgressEventType int
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const (
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// TransferStartedEvent transfer started, set TotalBytes
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TransferStartedEvent ProgressEventType = 1 + iota
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// TransferDataEvent transfer data, set ConsumedBytes anmd TotalBytes
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TransferDataEvent
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// TransferCompletedEvent transfer completed
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TransferCompletedEvent
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// TransferFailedEvent transfer encounters an error
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TransferFailedEvent
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)
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// ProgressEvent defines progress event
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type ProgressEvent struct {
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ConsumedBytes int64
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TotalBytes int64
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EventType ProgressEventType
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}
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// ProgressListener listens progress change
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type ProgressListener interface {
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ProgressChanged(event *ProgressEvent)
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}
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// -------------------- Private --------------------
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func newProgressEvent(eventType ProgressEventType, consumed, total int64) *ProgressEvent {
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return &ProgressEvent{
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ConsumedBytes: consumed,
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TotalBytes: total,
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EventType: eventType}
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}
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// publishProgress
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func publishProgress(listener ProgressListener, event *ProgressEvent) {
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if listener != nil && event != nil {
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listener.ProgressChanged(event)
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}
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}
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type readerTracker struct {
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completedBytes int64
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}
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type teeReader struct {
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reader io.Reader
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writer io.Writer
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listener ProgressListener
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consumedBytes int64
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totalBytes int64
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tracker *readerTracker
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}
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// TeeReader returns a Reader that writes to w what it reads from r.
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// All reads from r performed through it are matched with
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// corresponding writes to w. There is no internal buffering -
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// the write must complete before the read completes.
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// Any error encountered while writing is reported as a read error.
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func TeeReader(reader io.Reader, writer io.Writer, totalBytes int64, listener ProgressListener, tracker *readerTracker) io.Reader {
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return &teeReader{
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reader: reader,
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writer: writer,
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listener: listener,
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consumedBytes: 0,
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totalBytes: totalBytes,
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tracker: tracker,
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}
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}
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func (t *teeReader) Read(p []byte) (n int, err error) {
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n, err = t.reader.Read(p)
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// Read encountered error
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if err != nil && err != io.EOF {
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event := newProgressEvent(TransferFailedEvent, t.consumedBytes, t.totalBytes)
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publishProgress(t.listener, event)
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}
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if n > 0 {
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t.consumedBytes += int64(n)
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// CRC
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if t.writer != nil {
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if n, err = t.writer.Write(p[:n]); err != nil {
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return n, err
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}
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}
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// Progress
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if t.listener != nil {
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event := newProgressEvent(TransferDataEvent, t.consumedBytes, t.totalBytes)
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publishProgress(t.listener, event)
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}
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// Track
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if t.tracker != nil {
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t.tracker.completedBytes = t.consumedBytes
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}
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}
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return
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}
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