| package request |
| |
| import ( |
| "io" |
| "sync" |
| |
| "github.com/aws/aws-sdk-go/internal/sdkio" |
| ) |
| |
| // offsetReader is a thread-safe io.ReadCloser to prevent racing |
| // with retrying requests |
| type offsetReader struct { |
| buf io.ReadSeeker |
| lock sync.Mutex |
| closed bool |
| } |
| |
| func newOffsetReader(buf io.ReadSeeker, offset int64) *offsetReader { |
| reader := &offsetReader{} |
| buf.Seek(offset, sdkio.SeekStart) |
| |
| reader.buf = buf |
| return reader |
| } |
| |
| // Close will close the instance of the offset reader's access to |
| // the underlying io.ReadSeeker. |
| func (o *offsetReader) Close() error { |
| o.lock.Lock() |
| defer o.lock.Unlock() |
| o.closed = true |
| return nil |
| } |
| |
| // Read is a thread-safe read of the underlying io.ReadSeeker |
| func (o *offsetReader) Read(p []byte) (int, error) { |
| o.lock.Lock() |
| defer o.lock.Unlock() |
| |
| if o.closed { |
| return 0, io.EOF |
| } |
| |
| return o.buf.Read(p) |
| } |
| |
| // Seek is a thread-safe seeking operation. |
| func (o *offsetReader) Seek(offset int64, whence int) (int64, error) { |
| o.lock.Lock() |
| defer o.lock.Unlock() |
| |
| return o.buf.Seek(offset, whence) |
| } |
| |
| // CloseAndCopy will return a new offsetReader with a copy of the old buffer |
| // and close the old buffer. |
| func (o *offsetReader) CloseAndCopy(offset int64) *offsetReader { |
| o.Close() |
| return newOffsetReader(o.buf, offset) |
| } |