mirror of https://github.com/rclone/rclone
48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
// Package chunkedreader provides functionality for reading a stream in chunks.
|
|
package chunkedreader
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"io"
|
|
|
|
"github.com/rclone/rclone/fs"
|
|
)
|
|
|
|
// io related errors returned by ChunkedReader
|
|
var (
|
|
ErrorFileClosed = errors.New("file already closed")
|
|
ErrorInvalidSeek = errors.New("invalid seek position")
|
|
)
|
|
|
|
// ChunkedReader describes what a chunked reader can do.
|
|
type ChunkedReader interface {
|
|
io.Reader
|
|
io.Seeker
|
|
io.Closer
|
|
fs.RangeSeeker
|
|
Open() (ChunkedReader, error)
|
|
}
|
|
|
|
// New returns a ChunkedReader for the Object.
|
|
//
|
|
// An initialChunkSize of <= 0 will disable chunked reading.
|
|
// If maxChunkSize is greater than initialChunkSize, the chunk size will be
|
|
// doubled after each chunk read with a maximum of maxChunkSize.
|
|
// A Seek or RangeSeek will reset the chunk size to it's initial value
|
|
func New(ctx context.Context, o fs.Object, initialChunkSize int64, maxChunkSize int64, streams int) ChunkedReader {
|
|
if initialChunkSize <= 0 {
|
|
initialChunkSize = -1
|
|
}
|
|
if maxChunkSize != -1 && maxChunkSize < initialChunkSize {
|
|
maxChunkSize = initialChunkSize
|
|
}
|
|
if streams < 0 {
|
|
streams = 0
|
|
}
|
|
if streams == 0 || o.Size() < 0 {
|
|
return newSequential(ctx, o, initialChunkSize, maxChunkSize)
|
|
}
|
|
return newParallel(ctx, o, initialChunkSize, streams)
|
|
}
|