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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [os/] [file.go] - Blame information for rev 867

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Line No. Rev Author Line
1 747 jeremybenn
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package os provides a platform-independent interface to operating system
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// functionality.  The design is Unix-like.
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// The os interface is intended to be uniform across all operating systems.
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// Features not generally available appear in the system-specific package syscall.
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package os
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import (
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        "io"
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        "syscall"
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)
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// Name returns the name of the file as presented to Open.
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func (f *File) Name() string { return f.name }
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// Stdin, Stdout, and Stderr are open Files pointing to the standard input,
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// standard output, and standard error file descriptors.
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var (
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        Stdin  = NewFile(syscall.Stdin, "/dev/stdin")
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        Stdout = NewFile(syscall.Stdout, "/dev/stdout")
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        Stderr = NewFile(syscall.Stderr, "/dev/stderr")
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)
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// Flags to Open wrapping those of the underlying system. Not all flags
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// may be implemented on a given system.
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const (
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        O_RDONLY   int = syscall.O_RDONLY   // open the file read-only.
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        O_WRONLY   int = syscall.O_WRONLY   // open the file write-only.
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        O_RDWR     int = syscall.O_RDWR     // open the file read-write.
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        O_APPEND   int = syscall.O_APPEND   // append data to the file when writing.
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        O_ASYNC    int = syscall.O_ASYNC    // generate a signal when I/O is available.
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        O_CREATE   int = syscall.O_CREAT    // create a new file if none exists.
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        O_EXCL     int = syscall.O_EXCL     // used with O_CREATE, file must not exist
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        O_NOCTTY   int = syscall.O_NOCTTY   // do not make file the controlling tty.
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        O_NONBLOCK int = syscall.O_NONBLOCK // open in non-blocking mode.
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        O_NDELAY   int = O_NONBLOCK         // synonym for O_NONBLOCK
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        O_SYNC     int = syscall.O_SYNC     // open for synchronous I/O.
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        O_TRUNC    int = syscall.O_TRUNC    // if possible, truncate file when opened.
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)
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// Seek whence values.
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const (
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        SEEK_SET int = 0 // seek relative to the origin of the file
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        SEEK_CUR int = 1 // seek relative to the current offset
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        SEEK_END int = 2 // seek relative to the end
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)
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// Read reads up to len(b) bytes from the File.
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// It returns the number of bytes read and an error, if any.
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// EOF is signaled by a zero count with err set to io.EOF.
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func (f *File) Read(b []byte) (n int, err error) {
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        if f == nil {
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                return 0, EINVAL
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        }
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        n, e := f.read(b)
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        if n < 0 {
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                n = 0
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        }
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        if n == 0 && len(b) > 0 && e == nil {
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                return 0, io.EOF
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        }
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        if e != nil {
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                err = &PathError{"read", f.name, e}
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        }
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        return n, err
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}
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// ReadAt reads len(b) bytes from the File starting at byte offset off.
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// It returns the number of bytes read and the error, if any.
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// ReadAt always returns a non-nil error when n < len(b).
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// At end of file, that error is io.EOF.
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func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
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        if f == nil {
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                return 0, EINVAL
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        }
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        for len(b) > 0 {
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                m, e := f.pread(b, off)
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                if m == 0 && e == nil {
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                        return n, io.EOF
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                }
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                if e != nil {
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                        err = &PathError{"read", f.name, e}
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                        break
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                }
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                n += m
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                b = b[m:]
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                off += int64(m)
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        }
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        return
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}
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// Write writes len(b) bytes to the File.
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// It returns the number of bytes written and an error, if any.
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// Write returns a non-nil error when n != len(b).
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func (f *File) Write(b []byte) (n int, err error) {
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        if f == nil {
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                return 0, EINVAL
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        }
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        n, e := f.write(b)
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        if n < 0 {
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                n = 0
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        }
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        epipecheck(f, e)
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        if e != nil {
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                err = &PathError{"write", f.name, e}
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        }
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        return n, err
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}
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// WriteAt writes len(b) bytes to the File starting at byte offset off.
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// It returns the number of bytes written and an error, if any.
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// WriteAt returns a non-nil error when n != len(b).
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func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
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        if f == nil {
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                return 0, EINVAL
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        }
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        for len(b) > 0 {
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                m, e := f.pwrite(b, off)
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                if e != nil {
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                        err = &PathError{"write", f.name, e}
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                        break
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                }
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                n += m
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                b = b[m:]
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                off += int64(m)
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        }
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        return
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}
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// Seek sets the offset for the next Read or Write on file to offset, interpreted
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// according to whence: 0 means relative to the origin of the file, 1 means
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// relative to the current offset, and 2 means relative to the end.
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// It returns the new offset and an error, if any.
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func (f *File) Seek(offset int64, whence int) (ret int64, err error) {
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        r, e := f.seek(offset, whence)
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        if e == nil && f.dirinfo != nil && r != 0 {
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                e = syscall.EISDIR
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        }
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        if e != nil {
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                return 0, &PathError{"seek", f.name, e}
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        }
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        return r, nil
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}
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// WriteString is like Write, but writes the contents of string s rather than
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// an array of bytes.
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func (f *File) WriteString(s string) (ret int, err error) {
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        if f == nil {
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                return 0, EINVAL
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        }
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        return f.Write([]byte(s))
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}
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// Mkdir creates a new directory with the specified name and permission bits.
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// It returns an error, if any.
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func Mkdir(name string, perm FileMode) error {
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        e := syscall.Mkdir(name, syscallMode(perm))
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        if e != nil {
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                return &PathError{"mkdir", name, e}
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        }
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        return nil
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}
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// Chdir changes the current working directory to the named directory.
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func Chdir(dir string) error {
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        if e := syscall.Chdir(dir); e != nil {
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                return &PathError{"chdir", dir, e}
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        }
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        return nil
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}
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// Chdir changes the current working directory to the file,
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// which must be a directory.
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func (f *File) Chdir() error {
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        if e := syscall.Fchdir(f.fd); e != nil {
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                return &PathError{"chdir", f.name, e}
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        }
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        return nil
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}
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// Open opens the named file for reading.  If successful, methods on
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// the returned file can be used for reading; the associated file
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// descriptor has mode O_RDONLY.
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// It returns the File and an error, if any.
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func Open(name string) (file *File, err error) {
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        return OpenFile(name, O_RDONLY, 0)
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}
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// Create creates the named file mode 0666 (before umask), truncating
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// it if it already exists.  If successful, methods on the returned
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// File can be used for I/O; the associated file descriptor has mode
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// O_RDWR.
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// It returns the File and an error, if any.
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func Create(name string) (file *File, err error) {
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        return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
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}

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