iopkg.go

package file

import (
        "os"
        "syscall"
)

type File struct {
        fd   int    // file descriptor number
        name string //file name at Open time
}

func newFile(fd int, name string) *File {
        if fd < 0 {
                return nil
        }
        return &File{fd, name}
}

var (
        Stdin  = newFile(0, "/dev/stdin")
        Stdout = newFile(1, "/dev/stdout")
        Stderr = newFile(2, "/dev/stderr")
)

func Open(name string, mode int, perm uint32) (file *File, err os.Error) {
        r, e := syscall.Open(name, mode, perm)
        if e != 0 {
                err = os.Errno(e)
        }
        return newFile(r, name), err
}
func (file *File) Close() os.Error {
        if file == nil {
                return os.EINVAL
        }
        e := syscall.Close(file.fd)
        file.fd = -1 // so it can't be closed again
        if e != 0 {
                return os.Errno(e)

        }
        return nil
}
func (file *File) Read(b []byte) (ret int, err os.Error) {
        if file == nil {
                return -1, os.EINVAL
        }
        r, e := syscall.Read(file.fd, b)
        if e != 0 {
                err = os.Errno(e)
        }
        return int(r), err
}

func (file *File) Write(b []byte) (ret int, err os.Error) {
        if file == nil {
                return -1, os.EINVAL
        }
        r, e := syscall.Write(file.fd, b)
        if e != 0 {
                err = os.Errno(e)
        }
        return int(r), err
}

func (file *File) String() string {
        return file.name