net: consolidate common socket functions

In resolving 3507, the fix had to be applied individually to
the four *Conn types, tcp, udp, rawip and unix, due to the
duplicate code in each Conn type.

This CL consolidates the common net.Conn methods that all four
*Conn types implement into a base conn type.

Pros:
* The fix for 3507 would have only needed to be applied to one
method. Further improvements, such as possibly removing the
c.fd != nil check in c.ok(), would benefit from this CL.
* Nearly 300 lines removed from the net package.
* The public interface and documentation are not changed.
* I think this is an excellent example of the power of embedding.

Cons:
* The net package is already distributed over many files, this
CL adds another place to look.
* The fix for 3507 was a total of 16 lines changed, this follow
up CL could be considered to be an overreaction as new Conn types
are unlikely to be added in the near future.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6098047

src/pkg/net/iprawsock_posix.go

@@ -9,9 +9,7 @@
 package net
 
 import (
-	"os"
 	"syscall"
-	"time"
 )
 
 func sockaddrToIP(sa syscall.Sockaddr) Addr {
@@ -55,94 +53,10 @@ func (a *IPAddr) toAddr() sockaddr {
 // IPConn is the implementation of the Conn and PacketConn
 // interfaces for IP network connections.
 type IPConn struct {
-	fd *netFD
+	conn
 }
 
-func newIPConn(fd *netFD) *IPConn { return &IPConn{fd} }
+func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
-
-func (c *IPConn) ok() bool { return c != nil && c.fd != nil }
-
-// Implementation of the Conn interface - see Conn for documentation.
-
-// Read implements the Conn Read method.
-func (c *IPConn) Read(b []byte) (int, error) {
-	n, _, err := c.ReadFrom(b)
-	return n, err
-}
-
-// Write implements the Conn Write method.
-func (c *IPConn) Write(b []byte) (int, error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Write(b)
-}
-
-// Close closes the IP connection.
-func (c *IPConn) Close() error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return c.fd.Close()
-}
-
-// LocalAddr returns the local network address.
-func (c *IPConn) LocalAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.laddr
-}
-
-// RemoteAddr returns the remote network address, a *IPAddr.
-func (c *IPConn) RemoteAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.raddr
-}
-
-// SetDeadline implements the Conn SetDeadline method.
-func (c *IPConn) SetDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setDeadline(c.fd, t)
-}
-
-// SetReadDeadline implements the Conn SetReadDeadline method.
-func (c *IPConn) SetReadDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadDeadline(c.fd, t)
-}
-
-// SetWriteDeadline implements the Conn SetWriteDeadline method.
-func (c *IPConn) SetWriteDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteDeadline(c.fd, t)
-}
-
-// SetReadBuffer sets the size of the operating system's
-// receive buffer associated with the connection.
-func (c *IPConn) SetReadBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadBuffer(c.fd, bytes)
-}
-
-// SetWriteBuffer sets the size of the operating system's
-// transmit buffer associated with the connection.
-func (c *IPConn) SetWriteBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteBuffer(c.fd, bytes)
-}
 
 // IP-specific methods.
 
@@ -255,8 +169,3 @@ func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
 	}
 	return newIPConn(fd), nil
 }
-
-// File returns a copy of the underlying os.File, set to blocking mode.
-// It is the caller's responsibility to close f when finished.
-// Closing c does not affect f, and closing f does not affect c.
-func (c *IPConn) File() (f *os.File, err error) { return c.fd.dup() }

src/pkg/net/net_posix.go

@@ -0,0 +1,110 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin freebsd linux netbsd openbsd windows
+
+// Base posix socket functions.
+
+package net
+
+import (
+	"os"
+	"syscall"
+	"time"
+)
+
+type conn struct {
+	fd *netFD
+}
+
+func (c *conn) ok() bool { return c != nil && c.fd != nil }
+
+// Implementation of the Conn interface - see Conn for documentation.
+
+// Read implements the Conn Read method.
+func (c *conn) Read(b []byte) (int, error) {
+	if !c.ok() {
+		return 0, syscall.EINVAL
+	}
+	return c.fd.Read(b)
+}
+
+// Write implements the Conn Write method.
+func (c *conn) Write(b []byte) (int, error) {
+	if !c.ok() {
+		return 0, syscall.EINVAL
+	}
+	return c.fd.Write(b)
+}
+
+// LocalAddr returns the local network address.
+func (c *conn) LocalAddr() Addr {
+	if !c.ok() {
+		return nil
+	}
+	return c.fd.laddr
+}
+
+// RemoteAddr returns the remote network address, a *UDPAddr.
+func (c *conn) RemoteAddr() Addr {
+	if !c.ok() {
+		return nil
+	}
+	return c.fd.raddr
+}
+
+// SetDeadline implements the Conn SetDeadline method.
+func (c *conn) SetDeadline(t time.Time) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setDeadline(c.fd, t)
+}
+
+// SetReadDeadline implements the Conn SetReadDeadline method.
+func (c *conn) SetReadDeadline(t time.Time) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setReadDeadline(c.fd, t)
+}
+
+// SetWriteDeadline implements the Conn SetWriteDeadline method.
+func (c *conn) SetWriteDeadline(t time.Time) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setWriteDeadline(c.fd, t)
+}
+
+// SetReadBuffer sets the size of the operating system's
+// receive buffer associated with the connection.
+func (c *conn) SetReadBuffer(bytes int) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setReadBuffer(c.fd, bytes)
+}
+
+// SetWriteBuffer sets the size of the operating system's
+// transmit buffer associated with the connection.
+func (c *conn) SetWriteBuffer(bytes int) error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return setWriteBuffer(c.fd, bytes)
+}
+
+// File returns a copy of the underlying os.File, set to blocking mode.
+// It is the caller's responsibility to close f when finished.
+// Closing c does not affect f, and closing f does not affect c.
+func (c *conn) File() (f *os.File, err error) { return c.fd.dup() }
+
+// Close closes the connection.
+func (c *conn) Close() error {
+	if !c.ok() {
+		return syscall.EINVAL
+	}
+	return c.fd.Close()
+}

src/pkg/net/tcpsock_posix.go

@@ -66,27 +66,15 @@ func (a *TCPAddr) toAddr() sockaddr {
 // TCPConn is an implementation of the Conn interface
 // for TCP network connections.
 type TCPConn struct {
-	fd *netFD
+	conn
 }
 
 func newTCPConn(fd *netFD) *TCPConn {
-	c := &TCPConn{fd}
+	c := &TCPConn{conn{fd}}
 	c.SetNoDelay(true)
 	return c
 }
 
-func (c *TCPConn) ok() bool { return c != nil && c.fd != nil }
-
-// Implementation of the Conn interface - see Conn for documentation.
-
-// Read implements the Conn Read method.
-func (c *TCPConn) Read(b []byte) (n int, err error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Read(b)
-}
-
 // ReadFrom implements the io.ReaderFrom ReadFrom method.
 func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
 	if n, err, handled := sendFile(c.fd, r); handled {
@@ -95,22 +83,6 @@ func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
 	return genericReadFrom(c, r)
 }
 
-// Write implements the Conn Write method.
-func (c *TCPConn) Write(b []byte) (n int, err error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Write(b)
-}
-
-// Close closes the TCP connection.
-func (c *TCPConn) Close() error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return c.fd.Close()
-}
-
 // CloseRead shuts down the reading side of the TCP connection.
 // Most callers should just use Close.
 func (c *TCPConn) CloseRead() error {
@@ -129,64 +101,6 @@ func (c *TCPConn) CloseWrite() error {
 	return c.fd.CloseWrite()
 }
 
-// LocalAddr returns the local network address, a *TCPAddr.
-func (c *TCPConn) LocalAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.laddr
-}
-
-// RemoteAddr returns the remote network address, a *TCPAddr.
-func (c *TCPConn) RemoteAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.raddr
-}
-
-// SetDeadline implements the Conn SetDeadline method.
-func (c *TCPConn) SetDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setDeadline(c.fd, t)
-}
-
-// SetReadDeadline implements the Conn SetReadDeadline method.
-func (c *TCPConn) SetReadDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadDeadline(c.fd, t)
-}
-
-// SetWriteDeadline implements the Conn SetWriteDeadline method.
-func (c *TCPConn) SetWriteDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteDeadline(c.fd, t)
-}
-
-// SetReadBuffer sets the size of the operating system's
-// receive buffer associated with the connection.
-func (c *TCPConn) SetReadBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadBuffer(c.fd, bytes)
-}
-
-// SetWriteBuffer sets the size of the operating system's
-// transmit buffer associated with the connection.
-func (c *TCPConn) SetWriteBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteBuffer(c.fd, bytes)
-}
-
 // SetLinger sets the behavior of Close() on a connection
 // which still has data waiting to be sent or to be acknowledged.
 //
@@ -225,11 +139,6 @@ func (c *TCPConn) SetNoDelay(noDelay bool) error {
 	return setNoDelay(c.fd, noDelay)
 }
 
-// File returns a copy of the underlying os.File, set to blocking mode.
-// It is the caller's responsibility to close f when finished.
-// Closing c does not affect f, and closing f does not affect c.
-func (c *TCPConn) File() (f *os.File, err error) { return c.fd.dup() }
-
 // DialTCP connects to the remote address raddr on the network net,
 // which must be "tcp", "tcp4", or "tcp6".  If laddr is not nil, it is used
 // as the local address for the connection.

src/pkg/net/udpsock_posix.go

@@ -10,9 +10,7 @@ package net
 
 import (
 	"errors"
-	"os"
 	"syscall"
-	"time"
 )
 
 var ErrWriteToConnected = errors.New("use of WriteTo with pre-connected UDP")
@@ -58,96 +56,10 @@ func (a *UDPAddr) toAddr() sockaddr {
 // UDPConn is the implementation of the Conn and PacketConn
 // interfaces for UDP network connections.
 type UDPConn struct {
-	fd *netFD
+	conn
 }
 
-func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{fd} }
+func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
-
-func (c *UDPConn) ok() bool { return c != nil && c.fd != nil }
-
-// Implementation of the Conn interface - see Conn for documentation.
-
-// Read implements the Conn Read method.
-func (c *UDPConn) Read(b []byte) (int, error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Read(b)
-}
-
-// Write implements the Conn Write method.
-func (c *UDPConn) Write(b []byte) (int, error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Write(b)
-}
-
-// Close closes the UDP connection.
-func (c *UDPConn) Close() error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return c.fd.Close()
-}
-
-// LocalAddr returns the local network address.
-func (c *UDPConn) LocalAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.laddr
-}
-
-// RemoteAddr returns the remote network address, a *UDPAddr.
-func (c *UDPConn) RemoteAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.raddr
-}
-
-// SetDeadline implements the Conn SetDeadline method.
-func (c *UDPConn) SetDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setDeadline(c.fd, t)
-}
-
-// SetReadDeadline implements the Conn SetReadDeadline method.
-func (c *UDPConn) SetReadDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadDeadline(c.fd, t)
-}
-
-// SetWriteDeadline implements the Conn SetWriteDeadline method.
-func (c *UDPConn) SetWriteDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteDeadline(c.fd, t)
-}
-
-// SetReadBuffer sets the size of the operating system's
-// receive buffer associated with the connection.
-func (c *UDPConn) SetReadBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadBuffer(c.fd, bytes)
-}
-
-// SetWriteBuffer sets the size of the operating system's
-// transmit buffer associated with the connection.
-func (c *UDPConn) SetWriteBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteBuffer(c.fd, bytes)
-}
 
 // UDP-specific methods.
 
@@ -212,11 +124,6 @@ func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
 	return c.WriteToUDP(b, a)
 }
 
-// File returns a copy of the underlying os.File, set to blocking mode.
-// It is the caller's responsibility to close f when finished.
-// Closing c does not affect f, and closing f does not affect c.
-func (c *UDPConn) File() (f *os.File, err error) { return c.fd.dup() }
-
 // DialUDP connects to the remote address raddr on the network net,
 // which must be "udp", "udp4", or "udp6".  If laddr is not nil, it is used
 // as the local address for the connection.

src/pkg/net/unixsock_posix.go

@@ -111,99 +111,10 @@ func sotypeToNet(sotype int) string {
 // UnixConn is an implementation of the Conn interface
 // for connections to Unix domain sockets.
 type UnixConn struct {
-	fd *netFD
+	conn
 }
 
-func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{fd} }
+func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{conn{fd}} }
-
-func (c *UnixConn) ok() bool { return c != nil && c.fd != nil }
-
-// Implementation of the Conn interface - see Conn for documentation.
-
-// Read implements the Conn Read method.
-func (c *UnixConn) Read(b []byte) (n int, err error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Read(b)
-}
-
-// Write implements the Conn Write method.
-func (c *UnixConn) Write(b []byte) (n int, err error) {
-	if !c.ok() {
-		return 0, syscall.EINVAL
-	}
-	return c.fd.Write(b)
-}
-
-// Close closes the Unix domain connection.
-func (c *UnixConn) Close() error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return c.fd.Close()
-}
-
-// LocalAddr returns the local network address, a *UnixAddr.
-// Unlike in other protocols, LocalAddr is usually nil for dialed connections.
-func (c *UnixConn) LocalAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.laddr
-}
-
-// RemoteAddr returns the remote network address, a *UnixAddr.
-// Unlike in other protocols, RemoteAddr is usually nil for connections
-// accepted by a listener.
-func (c *UnixConn) RemoteAddr() Addr {
-	if !c.ok() {
-		return nil
-	}
-	return c.fd.raddr
-}
-
-// SetDeadline implements the Conn SetDeadline method.
-func (c *UnixConn) SetDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setDeadline(c.fd, t)
-}
-
-// SetReadDeadline implements the Conn SetReadDeadline method.
-func (c *UnixConn) SetReadDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadDeadline(c.fd, t)
-}
-
-// SetWriteDeadline implements the Conn SetWriteDeadline method.
-func (c *UnixConn) SetWriteDeadline(t time.Time) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteDeadline(c.fd, t)
-}
-
-// SetReadBuffer sets the size of the operating system's
-// receive buffer associated with the connection.
-func (c *UnixConn) SetReadBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setReadBuffer(c.fd, bytes)
-}
-
-// SetWriteBuffer sets the size of the operating system's
-// transmit buffer associated with the connection.
-func (c *UnixConn) SetWriteBuffer(bytes int) error {
-	if !c.ok() {
-		return syscall.EINVAL
-	}
-	return setWriteBuffer(c.fd, bytes)
-}
 
 // ReadFromUnix reads a packet from c, copying the payload into b.
 // It returns the number of bytes copied into b and the source address
@@ -296,11 +207,6 @@ func (c *UnixConn) WriteMsgUnix(b, oob []byte, addr *UnixAddr) (n, oobn int, err
 	return c.fd.WriteMsg(b, oob, nil)
 }
 
-// File returns a copy of the underlying os.File, set to blocking mode.
-// It is the caller's responsibility to close f when finished.
-// Closing c does not affect f, and closing f does not affect c.
-func (c *UnixConn) File() (f *os.File, err error) { return c.fd.dup() }
-
 // DialUnix connects to the remote address raddr on the network net,
 // which must be "unix" or "unixgram".  If laddr is not nil, it is used
 // as the local address for the connection.