diff options
author | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:13:40 +0200 |
---|---|---|
committer | Ondřej Surý <ondrej@sury.org> | 2011-09-13 13:13:40 +0200 |
commit | 5ff4c17907d5b19510a62e08fd8d3b11e62b431d (patch) | |
tree | c0650497e988f47be9c6f2324fa692a52dea82e1 /src/pkg/os/file_unix.go | |
parent | 80f18fc933cf3f3e829c5455a1023d69f7b86e52 (diff) | |
download | golang-upstream/60.tar.gz |
Imported Upstream version 60upstream/60
Diffstat (limited to 'src/pkg/os/file_unix.go')
-rw-r--r-- | src/pkg/os/file_unix.go | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/pkg/os/file_unix.go b/src/pkg/os/file_unix.go new file mode 100644 index 000000000..301c2f473 --- /dev/null +++ b/src/pkg/os/file_unix.go @@ -0,0 +1,208 @@ +// 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 + +import ( + "runtime" + "syscall" +) + +// File represents an open file descriptor. +type File struct { + fd int + name string + dirinfo *dirInfo // nil unless directory being read + nepipe int // number of consecutive EPIPE in Write +} + +// Fd returns the integer Unix file descriptor referencing the open file. +func (file *File) Fd() int { + if file == nil { + return -1 + } + return file.fd +} + +// NewFile returns a new File with the given file descriptor and name. +func NewFile(fd int, name string) *File { + if fd < 0 { + return nil + } + f := &File{fd: fd, name: name} + runtime.SetFinalizer(f, (*File).Close) + return f +} + +// Auxiliary information if the File describes a directory +type dirInfo struct { + buf []byte // buffer for directory I/O + nbuf int // length of buf; return value from Getdirentries + bufp int // location of next record in buf. +} + +// DevNull is the name of the operating system's ``null device.'' +// On Unix-like systems, it is "/dev/null"; on Windows, "NUL". +const DevNull = "/dev/null" + +// OpenFile is the generalized open call; most users will use Open +// or Create instead. It opens the named file with specified flag +// (O_RDONLY etc.) and perm, (0666 etc.) if applicable. If successful, +// methods on the returned File can be used for I/O. +// It returns the File and an Error, if any. +func OpenFile(name string, flag int, perm uint32) (file *File, err Error) { + r, e := syscall.Open(name, flag|syscall.O_CLOEXEC, perm) + if e != 0 { + return nil, &PathError{"open", name, Errno(e)} + } + + // There's a race here with fork/exec, which we are + // content to live with. See ../syscall/exec.go + if syscall.O_CLOEXEC == 0 { // O_CLOEXEC not supported + syscall.CloseOnExec(r) + } + + return NewFile(r, name), nil +} + +// Close closes the File, rendering it unusable for I/O. +// It returns an Error, if any. +func (file *File) Close() Error { + if file == nil || file.fd < 0 { + return EINVAL + } + var err Error + if e := syscall.Close(file.fd); e != 0 { + err = &PathError{"close", file.name, Errno(e)} + } + file.fd = -1 // so it can't be closed again + + // no need for a finalizer anymore + runtime.SetFinalizer(file, nil) + return err +} + +// Stat returns the FileInfo structure describing file. +// It returns the FileInfo and an error, if any. +func (file *File) Stat() (fi *FileInfo, err Error) { + var stat syscall.Stat_t + e := syscall.Fstat(file.fd, &stat) + if e != 0 { + return nil, &PathError{"stat", file.name, Errno(e)} + } + return fileInfoFromStat(file.name, new(FileInfo), &stat, &stat), nil +} + +// Readdir reads the contents of the directory associated with file and +// returns an array of up to n FileInfo structures, as would be returned +// by Lstat, in directory order. Subsequent calls on the same file will yield +// further FileInfos. +// +// If n > 0, Readdir returns at most n FileInfo structures. In this case, if +// Readdir returns an empty slice, it will return a non-nil error +// explaining why. At the end of a directory, the error is os.EOF. +// +// If n <= 0, Readdir returns all the FileInfo from the directory in +// a single slice. In this case, if Readdir succeeds (reads all +// the way to the end of the directory), it returns the slice and a +// nil os.Error. If it encounters an error before the end of the +// directory, Readdir returns the FileInfo read until that point +// and a non-nil error. +func (file *File) Readdir(n int) (fi []FileInfo, err Error) { + dirname := file.name + if dirname == "" { + dirname = "." + } + dirname += "/" + names, err := file.Readdirnames(n) + fi = make([]FileInfo, len(names)) + for i, filename := range names { + fip, err := Lstat(dirname + filename) + if fip == nil || err != nil { + fi[i].Name = filename // rest is already zeroed out + } else { + fi[i] = *fip + } + } + return +} + +// read reads up to len(b) bytes from the File. +// It returns the number of bytes read and an error, if any. +func (f *File) read(b []byte) (n int, err int) { + return syscall.Read(f.fd, b) +} + +// pread 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 0. +func (f *File) pread(b []byte, off int64) (n int, err int) { + return syscall.Pread(f.fd, b, off) +} + +// write writes len(b) bytes to the File. +// It returns the number of bytes written and an error, if any. +func (f *File) write(b []byte) (n int, err int) { + return syscall.Write(f.fd, b) +} + +// pwrite writes len(b) bytes to the File starting at byte offset off. +// It returns the number of bytes written and an error, if any. +func (f *File) pwrite(b []byte, off int64) (n int, err int) { + return syscall.Pwrite(f.fd, b, off) +} + +// 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 (f *File) seek(offset int64, whence int) (ret int64, err int) { + return syscall.Seek(f.fd, offset, whence) +} + +// Truncate changes the size of the named file. +// If the file is a symbolic link, it changes the size of the link's target. +func Truncate(name string, size int64) Error { + if e := syscall.Truncate(name, size); e != 0 { + return &PathError{"truncate", name, Errno(e)} + } + return nil +} + +// basename removes trailing slashes and the leading directory name from path name +func basename(name string) string { + i := len(name) - 1 + // Remove trailing slashes + for ; i > 0 && name[i] == '/'; i-- { + name = name[:i] + } + // Remove leading directory name + for i--; i >= 0; i-- { + if name[i] == '/' { + name = name[i+1:] + break + } + } + + return name +} + +// Pipe returns a connected pair of Files; reads from r return bytes written to w. +// It returns the files and an Error, if any. +func Pipe() (r *File, w *File, err Error) { + var p [2]int + + // See ../syscall/exec.go for description of lock. + syscall.ForkLock.RLock() + e := syscall.Pipe(p[0:]) + if iserror(e) { + syscall.ForkLock.RUnlock() + return nil, nil, NewSyscallError("pipe", e) + } + syscall.CloseOnExec(p[0]) + syscall.CloseOnExec(p[1]) + syscall.ForkLock.RUnlock() + + return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil +} |