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streamreader.go
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streamreader.go
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package sdk
import (
"context"
"io"
"github.com/0chain/errors"
)
// Example implementation of a reader
type DataChan struct {
data []byte
err error
}
func NewStreamReader(dataChan chan *DataChan) *StreamReader {
return &StreamReader{dataChan}
}
type StreamReader struct {
dataChan chan *DataChan
}
// Client should always send bytes equal to less than chunkDataSizePerRead
func (r *StreamReader) Read(p []byte) (int, error) {
recieveData, ok := <-r.dataChan
if !ok && recieveData == nil {
return 0, io.EOF
}
if recieveData.err != nil {
return 0, recieveData.err
}
if len(recieveData.data) > len(p) {
return 0, io.ErrShortBuffer
}
copy(p, recieveData.data)
return len(recieveData.data), nil
}
func StartWriteWorker(ctx context.Context, source io.Reader, dataChan chan *DataChan, chunkDataSizePerRead int64) {
defer close(dataChan)
for {
select {
case <-ctx.Done():
return
default:
}
data := make([]byte, chunkDataSizePerRead)
dataToSend := &DataChan{}
n, err := source.Read(data)
if n < int(chunkDataSizePerRead) {
data = data[:n]
}
if err != nil && !errors.Is(err, io.EOF) {
dataToSend.err = err
dataChan <- dataToSend
return
}
dataToSend.data = data
dataChan <- dataToSend
if n < int(chunkDataSizePerRead) {
return
}
}
}