1 files changed, 211 insertions, 0 deletions
diff --git a/src/pkg/os/file.go b/src/pkg/os/file.go
new file mode 100644
index 000000000..4335d45e5
--- /dev/null
+++ b/src/pkg/os/file.go
@@ -0,0 +1,211 @@
+// Copyright 2009 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.
+
+// Package os provides a platform-independent interface to operating system
+// functionality.  The design is Unix-like.
+// The os interface is intended to be uniform across all operating systems.
+// Features not generally available appear in the system-specific package syscall.
+package os
+
+import (
+	"syscall"
+)
+
+// Name returns the name of the file as presented to Open.
+func (file *File) Name() string { return file.name }
+
+// Stdin, Stdout, and Stderr are open Files pointing to the standard input,
+// standard output, and standard error file descriptors.
+var (
+	Stdin  = NewFile(syscall.Stdin, "/dev/stdin")
+	Stdout = NewFile(syscall.Stdout, "/dev/stdout")
+	Stderr = NewFile(syscall.Stderr, "/dev/stderr")
+)
+
+// Flags to Open wrapping those of the underlying system. Not all flags
+// may be implemented on a given system.
+const (
+	O_RDONLY   int = syscall.O_RDONLY   // open the file read-only.
+	O_WRONLY   int = syscall.O_WRONLY   // open the file write-only.
+	O_RDWR     int = syscall.O_RDWR     // open the file read-write.
+	O_APPEND   int = syscall.O_APPEND   // append data to the file when writing.
+	O_ASYNC    int = syscall.O_ASYNC    // generate a signal when I/O is available.
+	O_CREATE   int = syscall.O_CREAT    // create a new file if none exists.
+	O_EXCL     int = syscall.O_EXCL     // used with O_CREATE, file must not exist
+	O_NOCTTY   int = syscall.O_NOCTTY   // do not make file the controlling tty.
+	O_NONBLOCK int = syscall.O_NONBLOCK // open in non-blocking mode.
+	O_NDELAY   int = O_NONBLOCK         // synonym for O_NONBLOCK
+	O_SYNC     int = syscall.O_SYNC     // open for synchronous I/O.
+	O_TRUNC    int = syscall.O_TRUNC    // if possible, truncate file when opened.
+)
+
+// Seek whence values.
+const (
+	SEEK_SET int = 0 // seek relative to the origin of the file
+	SEEK_CUR int = 1 // seek relative to the current offset
+	SEEK_END int = 2 // seek relative to the end
+)
+
+type eofError int
+
+func (eofError) String() string { return "EOF" }
+
+// EOF is the Error returned by Read when no more input is available.
+// Functions should return EOF only to signal a graceful end of input.
+// If the EOF occurs unexpectedly in a structured data stream,
+// the appropriate error is either io.ErrUnexpectedEOF or some other error
+// giving more detail.
+var EOF Error = eofError(0)
+
+// Read reads up to len(b) bytes from the File.
+// It returns the number of bytes read and an Error, if any.
+// EOF is signaled by a zero count with err set to EOF.
+func (file *File) Read(b []byte) (n int, err Error) {
+	if file == nil {
+		return 0, EINVAL
+	}
+	n, e := file.read(b)
+	if n < 0 {
+		n = 0
+	}
+	if n == 0 && !iserror(e) {
+		return 0, EOF
+	}
+	if iserror(e) {
+		err = &PathError{"read", file.name, Errno(e)}
+	}
+	return n, err
+}
+
+// ReadAt reads len(b) bytes from the File starting at byte offset off.
+// It returns the number of bytes read and the Error, if any.
+// EOF is signaled by a zero count with err set to EOF.
+// ReadAt always returns a non-nil Error when n != len(b).
+func (file *File) ReadAt(b []byte, off int64) (n int, err Error) {
+	if file == nil {
+		return 0, EINVAL
+	}
+	for len(b) > 0 {
+		m, e := file.pread(b, off)
+		if m == 0 && !iserror(e) {
+			return n, EOF
+		}
+		if iserror(e) {
+			err = &PathError{"read", file.name, Errno(e)}
+			break
+		}
+		n += m
+		b = b[m:]
+		off += int64(m)
+	}
+	return
+}
+
+// Write writes len(b) bytes to the File.
+// It returns the number of bytes written and an Error, if any.
+// Write returns a non-nil Error when n != len(b).
+func (file *File) Write(b []byte) (n int, err Error) {
+	if file == nil {
+		return 0, EINVAL
+	}
+	n, e := file.write(b)
+	if n < 0 {
+		n = 0
+	}
+
+	epipecheck(file, e)
+
+	if iserror(e) {
+		err = &PathError{"write", file.name, Errno(e)}
+	}
+	return n, err
+}
+
+// WriteAt writes len(b) bytes to the File starting at byte offset off.
+// It returns the number of bytes written and an Error, if any.
+// WriteAt returns a non-nil Error when n != len(b).
+func (file *File) WriteAt(b []byte, off int64) (n int, err Error) {
+	if file == nil {
+		return 0, EINVAL
+	}
+	for len(b) > 0 {
+		m, e := file.pwrite(b, off)
+		if iserror(e) {
+			err = &PathError{"write", file.name, Errno(e)}
+			break
+		}
+		n += m
+		b = b[m:]
+		off += int64(m)
+	}
+	return
+}
+
+// Seek sets the offset for the next Read or Write on file to offset, interpreted
+// according to whence: 0 means relative to the origin of the file, 1 means
+// relative to the current offset, and 2 means relative to the end.
+// It returns the new offset and an Error, if any.
+func (file *File) Seek(offset int64, whence int) (ret int64, err Error) {
+	r, e := file.seek(offset, whence)
+	if !iserror(e) && file.dirinfo != nil && r != 0 {
+		e = syscall.EISDIR
+	}
+	if iserror(e) {
+		return 0, &PathError{"seek", file.name, Errno(e)}
+	}
+	return r, nil
+}
+
+// WriteString is like Write, but writes the contents of string s rather than
+// an array of bytes.
+func (file *File) WriteString(s string) (ret int, err Error) {
+	if file == nil {
+		return 0, EINVAL
+	}
+	return file.Write([]byte(s))
+}
+
+// Mkdir creates a new directory with the specified name and permission bits.
+// It returns an error, if any.
+func Mkdir(name string, perm uint32) Error {
+	e := syscall.Mkdir(name, perm)
+	if iserror(e) {
+		return &PathError{"mkdir", name, Errno(e)}
+	}
+	return nil
+}
+
+// Chdir changes the current working directory to the named directory.
+func Chdir(dir string) Error {
+	if e := syscall.Chdir(dir); iserror(e) {
+		return &PathError{"chdir", dir, Errno(e)}
+	}
+	return nil
+}
+
+// Chdir changes the current working directory to the file,
+// which must be a directory.
+func (f *File) Chdir() Error {
+	if e := syscall.Fchdir(f.fd); iserror(e) {
+		return &PathError{"chdir", f.name, Errno(e)}
+	}
+	return nil
+}
+
+// Open opens the named file for reading.  If successful, methods on
+// the returned file can be used for reading; the associated file
+// descriptor has mode O_RDONLY.
+// It returns the File and an Error, if any.
+func Open(name string) (file *File, err Error) {
+	return OpenFile(name, O_RDONLY, 0)
+}
+
+// Create creates the named file mode 0666 (before umask), truncating
+// it if it already exists.  If successful, methods on the returned
+// File can be used for I/O; the associated file descriptor has mode
+// O_RDWR.
+// It returns the File and an Error, if any.
+func Create(name string) (file *File, err Error) {
+	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
+}