go.uber.org/yarpc@v1.72.1/compressor/grpc/grpc.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  // Package yarpcgrpccompressor provides an adapter for YARPC compressors to
    22  // gRPC compressors.
    23  //
    24  // The only distinction is that YARPC's Decompressor returns an io.ReadCloser
    25  // instead of a mere io.Reader.
    26  // gRPC does not call Close, so must infer the end of stream by returning the
    27  // reader to the reader pool when Read returns io.EOF.
    28  // This wrapper uses the io.EOF to trigger and automatic Close.
    29  package yarpcgrpccompressor
    30  
    31  import (
    32  	"io"
    33  
    34  	"go.uber.org/yarpc/api/transport"
    35  	"google.golang.org/grpc/encoding"
    36  )
    37  
    38  // New adapts a YARPC compressor to a gRPC compressor.
    39  func New(compressor transport.Compressor) encoding.Compressor {
    40  	return &Compressor{compressor: compressor}
    41  }
    42  
    43  // Compressor is a gRPC compressor that wraps a YARPC compressor.
    44  type Compressor struct {
    45  	compressor transport.Compressor
    46  }
    47  
    48  var _ encoding.Compressor = (*Compressor)(nil)
    49  
    50  // Name returns the name of the underlying compressor.
    51  func (c *Compressor) Name() string {
    52  	return c.compressor.Name()
    53  }
    54  
    55  // Compress wraps a writer with a compressing writer.
    56  func (c *Compressor) Compress(w io.Writer) (io.WriteCloser, error) {
    57  	return c.compressor.Compress(w)
    58  }
    59  
    60  // Decompress wraps a reader with a decompressing reader.
    61  func (c *Compressor) Decompress(r io.Reader) (io.Reader, error) {
    62  	dr, err := c.compressor.Decompress(r)
    63  	if err != nil {
    64  		return nil, err
    65  	}
    66  	return &reader{reader: dr}, nil
    67  }
    68  
    69  type reader struct {
    70  	reader io.ReadCloser
    71  }
    72  
    73  var _ io.Reader = (*reader)(nil)
    74  
    75  func (r *reader) Read(buf []byte) (n int, err error) {
    76  	n, err = r.reader.Read(buf)
    77  	if err == io.EOF {
    78  		r.reader.Close()
    79  	}
    80  	return n, err
    81  }