github.com/minio/minio@v0.0.0-20240328213742-3f72439b8a27/internal/ioutil/wait_pipe.go (about)

     1  // Copyright (c) 2015-2021 MinIO, Inc.
     2  //
     3  // This file is part of MinIO Object Storage stack
     4  //
     5  // This program is free software: you can redistribute it and/or modify
     6  // it under the terms of the GNU Affero General Public License as published by
     7  // the Free Software Foundation, either version 3 of the License, or
     8  // (at your option) any later version.
     9  //
    10  // This program is distributed in the hope that it will be useful
    11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13  // GNU Affero General Public License for more details.
    14  //
    15  // You should have received a copy of the GNU Affero General Public License
    16  // along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17  
    18  package ioutil
    19  
    20  import (
    21  	"io"
    22  	"sync"
    23  )
    24  
    25  // PipeWriter is similar to io.PipeWriter with wait group
    26  type PipeWriter struct {
    27  	*io.PipeWriter
    28  	once sync.Once
    29  	done func()
    30  }
    31  
    32  // CloseWithError close with supplied error the writer end.
    33  func (w *PipeWriter) CloseWithError(err error) error {
    34  	err = w.PipeWriter.CloseWithError(err)
    35  	w.once.Do(func() {
    36  		w.done()
    37  	})
    38  	return err
    39  }
    40  
    41  // PipeReader is similar to io.PipeReader with wait group
    42  type PipeReader struct {
    43  	*io.PipeReader
    44  	wait func()
    45  }
    46  
    47  // CloseWithError close with supplied error the reader end
    48  func (r *PipeReader) CloseWithError(err error) error {
    49  	err = r.PipeReader.CloseWithError(err)
    50  	r.wait()
    51  	return err
    52  }
    53  
    54  // WaitPipe implements wait-group backend io.Pipe to provide
    55  // synchronization between read() end with write() end.
    56  func WaitPipe() (*PipeReader, *PipeWriter) {
    57  	r, w := io.Pipe()
    58  	var wg sync.WaitGroup
    59  	wg.Add(1)
    60  	return &PipeReader{
    61  			PipeReader: r,
    62  			wait:       wg.Wait,
    63  		}, &PipeWriter{
    64  			PipeWriter: w,
    65  			done:       wg.Done,
    66  		}
    67  }