github.com/m3db/m3@v1.5.0/src/msg/protocol/proto/encoder.go (about)

     1  // Copyright (c) 2018 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 proto
    22  
    23  import (
    24  	"fmt"
    25  
    26  	"github.com/m3db/m3/src/x/pool"
    27  )
    28  
    29  type encoder struct {
    30  	buffer         []byte
    31  	bytesPool      pool.BytesPool
    32  	maxMessageSize int
    33  	encoded        int
    34  }
    35  
    36  // NewEncoder creates a new encoder, the implementation is not thread safe.
    37  func NewEncoder(opts Options) Encoder {
    38  	if opts == nil {
    39  		opts = NewOptions()
    40  	}
    41  	pool := opts.BytesPool()
    42  	return &encoder{
    43  		buffer:         getByteSliceWithLength(sizeEncodingLength, pool),
    44  		bytesPool:      pool,
    45  		maxMessageSize: opts.MaxMessageSize(),
    46  	}
    47  }
    48  
    49  func (e *encoder) Encode(m Marshaler) error {
    50  	size := m.Size()
    51  	if size > e.maxMessageSize {
    52  		return fmt.Errorf("message size %d is larger than maximum supported size %d", size, e.maxMessageSize)
    53  	}
    54  	e.buffer = growDataBufferIfNeeded(e.buffer, sizeEncodingLength+size, e.bytesPool)
    55  	e.encodeSize(size)
    56  	if err := e.encodeData(e.buffer[sizeEncodingLength:], m); err != nil {
    57  		return err
    58  	}
    59  	e.encoded = sizeEncodingLength + size
    60  	return nil
    61  }
    62  
    63  func (e *encoder) Bytes() []byte {
    64  	return e.buffer[:e.encoded]
    65  }
    66  
    67  func (e *encoder) encodeSize(size int) {
    68  	sizeEncodeDecoder.PutUint32(e.buffer, uint32(size))
    69  }
    70  
    71  func (e *encoder) encodeData(buffer []byte, m Marshaler) error {
    72  	_, err := m.MarshalTo(buffer)
    73  	return err
    74  }