github.com/goplus/gop@v1.2.6/x/jsonrpc2/stdio/stdio.go (about)

     1  /*
     2   * Copyright (c) 2023 The GoPlus Authors (goplus.org). All rights reserved.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package stdio
    18  
    19  import (
    20  	"context"
    21  	"errors"
    22  	"io"
    23  	"sync/atomic"
    24  
    25  	"github.com/goplus/gop/x/fakenet"
    26  	"github.com/goplus/gop/x/jsonrpc2"
    27  )
    28  
    29  var (
    30  	ErrTooManyConnections = errors.New("too many connections")
    31  )
    32  
    33  const (
    34  	client = iota
    35  	server
    36  )
    37  
    38  var (
    39  	connCnt [2]int32
    40  )
    41  
    42  // -----------------------------------------------------------------------------
    43  
    44  type dialer struct {
    45  	in  io.ReadCloser
    46  	out io.WriteCloser
    47  }
    48  
    49  // Dial returns a new communication byte stream to a listening server.
    50  func (p *dialer) Dial(ctx context.Context) (io.ReadWriteCloser, error) {
    51  	dailCnt := &connCnt[client]
    52  	if atomic.AddInt32(dailCnt, 1) != 1 {
    53  		atomic.AddInt32(dailCnt, -1)
    54  		return nil, ErrTooManyConnections
    55  	}
    56  	return fakenet.NewConn("stdio.dialer", p.in, p.out), nil
    57  }
    58  
    59  // Dialer returns a jsonrpc2.Dialer based on in and out.
    60  func Dialer(in io.ReadCloser, out io.WriteCloser) jsonrpc2.Dialer {
    61  	return &dialer{in: in, out: out}
    62  }
    63  
    64  // Dial makes a new connection based on in and out, wraps the returned
    65  // reader and writer using the framer to make a stream, and then builds a
    66  // connection on top of that stream using the binder.
    67  //
    68  // The returned Connection will operate independently using the Preempter and/or
    69  // Handler provided by the Binder, and will release its own resources when the
    70  // connection is broken, but the caller may Close it earlier to stop accepting
    71  // (or sending) new requests.
    72  func Dial(in io.ReadCloser, out io.WriteCloser, binder jsonrpc2.Binder, onDone func()) (*jsonrpc2.Connection, error) {
    73  	return jsonrpc2.Dial(context.Background(), Dialer(in, out), binder, onDone)
    74  }
    75  
    76  // -----------------------------------------------------------------------------