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package pipeline
import "io"
// ********** The following is common between the request body AND the response body.
// ProgressReceiver defines the signature of a callback function invoked as progress is reported.
type ProgressReceiver func(bytesTransferred int64)
// ********** The following are specific to the request body (a ReadSeekCloser)
// This struct is used when sending a body to the network
type requestBodyProgress struct {
requestBody io.ReadSeeker // Seeking is required to support retries
pr ProgressReceiver
}
// NewRequestBodyProgress adds progress reporting to an HTTP request's body stream.
func NewRequestBodyProgress(requestBody io.ReadSeeker, pr ProgressReceiver) io.ReadSeeker {
if pr == nil {
panic("pr must not be nil")
}
return &requestBodyProgress{requestBody: requestBody, pr: pr}
}
// Read reads a block of data from an inner stream and reports progress
func (rbp *requestBodyProgress) Read(p []byte) (n int, err error) {
n, err = rbp.requestBody.Read(p)
if err != nil {
return
}
// Invokes the user's callback method to report progress
position, err := rbp.requestBody.Seek(0, io.SeekCurrent)
if err != nil {
panic(err)
}
rbp.pr(position)
return
}
func (rbp *requestBodyProgress) Seek(offset int64, whence int) (offsetFromStart int64, err error) {
return rbp.requestBody.Seek(offset, whence)
}
// requestBodyProgress supports Close but the underlying stream may not; if it does, Close will close it.
func (rbp *requestBodyProgress) Close() error {
if c, ok := rbp.requestBody.(io.Closer); ok {
return c.Close()
}
return nil
}
// ********** The following are specific to the response body (a ReadCloser)
// This struct is used when sending a body to the network
type responseBodyProgress struct {
responseBody io.ReadCloser
pr ProgressReceiver
offset int64
}
// NewResponseBodyProgress adds progress reporting to an HTTP response's body stream.
func NewResponseBodyProgress(responseBody io.ReadCloser, pr ProgressReceiver) io.ReadCloser {
if pr == nil {
panic("pr must not be nil")
}
return &responseBodyProgress{responseBody: responseBody, pr: pr, offset: 0}
}
// Read reads a block of data from an inner stream and reports progress
func (rbp *responseBodyProgress) Read(p []byte) (n int, err error) {
n, err = rbp.responseBody.Read(p)
rbp.offset += int64(n)
// Invokes the user's callback method to report progress
rbp.pr(rbp.offset)
return
}
func (rbp *responseBodyProgress) Close() error {
return rbp.responseBody.Close()
}