From 152558831e919803fd60169bceaa301518f47627 Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bug.st>
Date: Sun, 13 Nov 2016 23:44:13 +0100
Subject: [PATCH] Moved Pipe{} into own sub-package

It may be moved into a separate project at some point, who knows...
---
 pipe_unix.go      | 53 -------------------------------
 serial_unix.go    |  8 +++--
 unixutils/pipe.go | 80 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+), 56 deletions(-)
 delete mode 100644 pipe_unix.go
 create mode 100644 unixutils/pipe.go

diff --git a/pipe_unix.go b/pipe_unix.go
deleted file mode 100644
index 066f258..0000000
--- a/pipe_unix.go
+++ /dev/null
@@ -1,53 +0,0 @@
-//
-// Copyright 2014-2016 Cristian Maglie. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-//
-
-// +build linux darwin freebsd
-
-package serial // import "go.bug.st/serial.v1"
-
-import "syscall"
-
-// pipe is a small wrapper around unix-pipe syscall functions
-type pipe struct {
-	rd int
-	wr int
-}
-
-func newPipe() (*pipe, error) {
-	fds := []int{0, 0}
-	if err := syscall.Pipe(fds); err != nil {
-		return nil, err
-	}
-	return &pipe{rd: fds[0], wr: fds[1]}, nil
-}
-
-func (p *pipe) ReadFD() int {
-	return p.rd
-}
-
-func (p *pipe) WriteFD() int {
-	return p.wr
-}
-
-func (p *pipe) Write(data []byte) (int, error) {
-	return syscall.Write(p.wr, data)
-}
-
-func (p *pipe) Read(data []byte) (int, error) {
-	return syscall.Read(p.rd, data)
-}
-
-func (p *pipe) Close() error {
-	err1 := syscall.Close(p.rd)
-	err2 := syscall.Close(p.wr)
-	if err1 != nil {
-		return err1
-	}
-	if err2 != nil {
-		return err2
-	}
-	return nil
-}
diff --git a/serial_unix.go b/serial_unix.go
index 84488b5..a4ca1ee 100644
--- a/serial_unix.go
+++ b/serial_unix.go
@@ -16,6 +16,8 @@ import (
 	"syscall"
 	"unsafe"
 
+	"go.bug.st/serial.v1/unixutils"
+
 	"github.com/creack/goselect"
 )
 
@@ -23,7 +25,7 @@ type unixPort struct {
 	handle int
 
 	closeLock   sync.RWMutex
-	closeSignal *pipe
+	closeSignal *unixutils.Pipe
 }
 
 func (port *unixPort) Close() error {
@@ -137,8 +139,8 @@ func nativeOpen(portName string, mode *Mode) (*unixPort, error) {
 	port.acquireExclusiveAccess()
 
 	// This pipe is used as a signal to cancel blocking Read or Write
-	pipe, err := newPipe()
-	if err != nil {
+	pipe := &unixutils.Pipe{}
+	if err := pipe.Open(); err != nil {
 		port.Close()
 		return nil, &PortError{code: InvalidSerialPort, causedBy: err}
 	}
diff --git a/unixutils/pipe.go b/unixutils/pipe.go
new file mode 100644
index 0000000..567c739
--- /dev/null
+++ b/unixutils/pipe.go
@@ -0,0 +1,80 @@
+//
+// Copyright 2014-2016 Cristian Maglie. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+
+// +build linux darwin freebsd
+
+package unixutils // import "go.bug.st/serial.v1/unixutils"
+
+import "syscall"
+import "fmt"
+
+// Pipe represents a unix-pipe
+type Pipe struct {
+	opened bool
+	rd     int
+	wr     int
+}
+
+// Open creates a new pipe
+func (p *Pipe) Open() error {
+	fds := []int{0, 0}
+	if err := syscall.Pipe(fds); err != nil {
+		return err
+	}
+	p.rd = fds[0]
+	p.wr = fds[1]
+	p.opened = true
+	return nil
+}
+
+// ReadFD returns the file handle for the read side of the pipe.
+func (p *Pipe) ReadFD() int {
+	if !p.opened {
+		return -1
+	}
+	return p.rd
+}
+
+// WriteFD returns the flie handle for the write side of the pipe.
+func (p *Pipe) WriteFD() int {
+	if !p.opened {
+		return -1
+	}
+	return p.wr
+}
+
+// Write to the pipe the content of data. Returns the numbre of bytes written.
+func (p *Pipe) Write(data []byte) (int, error) {
+	if !p.opened {
+		return 0, fmt.Errorf("Pipe not opened")
+	}
+	return syscall.Write(p.wr, data)
+}
+
+// Read from the pipe into the data array. Returns the number of bytes read.
+func (p *Pipe) Read(data []byte) (int, error) {
+	if !p.opened {
+		return 0, fmt.Errorf("Pipe not opened")
+	}
+	return syscall.Read(p.rd, data)
+}
+
+// Close the pipe
+func (p *Pipe) Close() error {
+	if !p.opened {
+		return fmt.Errorf("Pipe not opened")
+	}
+	err1 := syscall.Close(p.rd)
+	err2 := syscall.Close(p.wr)
+	p.opened = false
+	if err1 != nil {
+		return err1
+	}
+	if err2 != nil {
+		return err2
+	}
+	return nil
+}