mirror of https://github.com/minio/minio.git
94 lines
2.6 KiB
Go
94 lines
2.6 KiB
Go
// Copyright (c) 2015-2023 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package grid
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import (
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"context"
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"errors"
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)
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// A Stream is a two-way stream.
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// All responses *must* be read by the caller.
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// If the call is canceled through the context,
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// the appropriate error will be returned.
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type Stream struct {
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// responses from the remote server.
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// Channel will be closed after error or when remote closes.
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// All responses *must* be read by the caller until either an error is returned or the channel is closed.
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// Canceling the context will cause the context cancellation error to be returned.
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responses <-chan Response
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cancel context.CancelCauseFunc
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// Requests sent to the server.
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// If the handler is defined with 0 incoming capacity this will be nil.
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// Channel *must* be closed to signal the end of the stream.
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// If the request context is canceled, the stream will no longer process requests.
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// Requests sent cannot be used any further by the called.
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Requests chan<- []byte
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ctx context.Context
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}
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// Send a payload to the remote server.
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func (s *Stream) Send(b []byte) error {
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if s.Requests == nil {
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return errors.New("stream does not accept requests")
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}
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select {
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case s.Requests <- b:
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return nil
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case <-s.ctx.Done():
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return context.Cause(s.ctx)
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}
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}
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// Results returns the results from the remote server one by one.
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// If any error is returned by the callback, the stream will be canceled.
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// If the context is canceled, the stream will be canceled.
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func (s *Stream) Results(next func(b []byte) error) (err error) {
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done := false
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defer func() {
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if !done {
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if s.cancel != nil {
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s.cancel(err)
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}
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// Drain channel.
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for range s.responses {
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}
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}
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}()
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for {
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select {
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case <-s.ctx.Done():
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return context.Cause(s.ctx)
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case resp, ok := <-s.responses:
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if !ok {
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done = true
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return nil
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}
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if resp.Err != nil {
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return resp.Err
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}
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err = next(resp.Msg)
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if err != nil {
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return err
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}
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}
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}
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}
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