ioconn - ioconn.go

     1  // Package ioconn allows any combination of an io.Reader, io.Writer and io.Closer to become a net.Conn.
     2  package ioconn // import "vimagination.zapto.org/ioconn"
     3  
     4  import (
     5  	"cmp"
     6  	"errors"
     7  	"io"
     8  	"net"
     9  	"time"
    10  )
    11  
    12  // CloserFunc is a func that implements the io.Closer interface allowing a
    13  // closure or other function to be io.Closer.
    14  type CloserFunc func() error
    15  
    16  // Close simply calls the CloserFunc func.
    17  func (c CloserFunc) Close() error {
    18  	return c()
    19  }
    20  
    21  // FileAddr is a net.Addr that represents a file. Should be a full path.
    22  type FileAddr string
    23  
    24  // Network always returns "file".
    25  func (f FileAddr) Network() string {
    26  	return "file"
    27  }
    28  
    29  // String returns file://path.
    30  func (f FileAddr) String() string {
    31  	return "file://" + string(f)
    32  }
    33  
    34  // Addr is a simple implementation of the net.Addr interface.
    35  type Addr struct {
    36  	Net, Str string
    37  }
    38  
    39  // Network returns the Net string.
    40  func (a Addr) Network() string {
    41  	return a.Net
    42  }
    43  
    44  // String returns the Str string.
    45  func (a Addr) String() string {
    46  	return a.Str
    47  }
    48  
    49  // Conn implements a net.Conn.
    50  type Conn struct {
    51  	io.Reader
    52  	io.Writer
    53  	io.Closer
    54  	Local, Remote               net.Addr
    55  	ReadDeadline, WriteDeadline time.Time
    56  }
    57  
    58  // Read implements the io.Reader interface.
    59  func (c *Conn) Read(p []byte) (int, error) {
    60  	if !c.ReadDeadline.IsZero() && time.Now().After(c.ReadDeadline) {
    61  		return 0, ErrTimeout
    62  	}
    63  
    64  	return c.Reader.Read(p)
    65  }
    66  
    67  // Write implements the io.Writer interface.
    68  func (c *Conn) Write(p []byte) (int, error) {
    69  	if !c.ReadDeadline.IsZero() && time.Now().After(c.WriteDeadline) {
    70  		return 0, ErrTimeout
    71  	}
    72  
    73  	return c.Writer.Write(p)
    74  }
    75  
    76  // LocalAddr returns the Local Address.
    77  func (c *Conn) LocalAddr() net.Addr {
    78  	return c.Local
    79  }
    80  
    81  // RemoteAddr returns the Remote Address.
    82  func (c *Conn) RemoteAddr() net.Addr {
    83  	return c.Remote
    84  }
    85  
    86  // SetDeadline implements the Conn SetDeadline method.
    87  func (c *Conn) SetDeadline(t time.Time) error {
    88  	return cmp.Or(c.SetReadDeadline(t), c.SetWriteDeadline(t))
    89  }
    90  
    91  // SetReadDeadline implements the Conn SetReadDeadline method.
    92  func (c *Conn) SetReadDeadline(t time.Time) error {
    93  	c.ReadDeadline = t
    94  
    95  	if rd, ok := c.Reader.(interface {
    96  		SetReadDeadline(time.Time) error
    97  	}); ok {
    98  		return rd.SetReadDeadline(t)
    99  	}
   100  
   101  	return nil
   102  }
   103  
   104  // SetWriteDeadline implements the Conn SetWriteDeadline method.
   105  func (c *Conn) SetWriteDeadline(t time.Time) error {
   106  	c.WriteDeadline = t
   107  
   108  	if wd, ok := c.Writer.(interface {
   109  		SetWriteDeadline(time.Time) error
   110  	}); ok {
   111  		return wd.SetWriteDeadline(t)
   112  	}
   113  
   114  	return nil
   115  }
   116  
   117  // Errors.
   118  var (
   119  	ErrTimeout = errors.New("timeout occurred")
   120  )
   121