tinygo/src/os/file.go
2021-12-14 09:25:27 +01:00

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// Portions 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 implements a subset of the Go "os" package. See
// https://godoc.org/os for details.
//
// Note that the current implementation is blocking. This limitation should be
// removed in a future version.
package os
import (
"io"
"syscall"
)
// Seek whence values.
//
// Deprecated: Use io.SeekStart, io.SeekCurrent, and io.SeekEnd.
const (
SEEK_SET int = io.SeekStart
SEEK_CUR int = io.SeekCurrent
SEEK_END int = io.SeekEnd
)
// Mkdir creates a directory. If the operation fails, it will return an error of
// type *PathError.
func Mkdir(path string, perm FileMode) error {
fs, suffix := findMount(path)
if fs == nil {
return &PathError{"mkdir", path, ErrNotExist}
}
err := fs.Mkdir(suffix, perm)
if err != nil {
return &PathError{"mkdir", path, err}
}
return nil
}
// Remove removes a file or (empty) directory. If the operation fails, it will
// return an error of type *PathError.
func Remove(path string) error {
fs, suffix := findMount(path)
if fs == nil {
return &PathError{"remove", path, ErrNotExist}
}
err := fs.Remove(suffix)
if err != nil {
return err
}
return nil
}
// Symlink is a stub, it is not implemented.
func Symlink(oldname, newname string) error {
return ErrNotImplemented
}
// RemoveAll is a stub, it is not implemented.
func RemoveAll(path string) error {
return ErrNotImplemented
}
// File represents an open file descriptor.
type File struct {
handle FileHandle
name string
}
// Name returns the name of the file with which it was opened.
func (f *File) Name() string {
return f.name
}
// OpenFile opens the named file. If the operation fails, the returned error
// will be of type *PathError.
func OpenFile(name string, flag int, perm FileMode) (*File, error) {
fs, suffix := findMount(name)
if fs == nil {
return nil, &PathError{"open", name, ErrNotExist}
}
handle, err := fs.OpenFile(suffix, flag, perm)
if err != nil {
return nil, &PathError{"open", name, err}
}
return &File{name: name, handle: handle}, nil
}
// Open opens the file named for reading.
func Open(name string) (*File, error) {
return OpenFile(name, O_RDONLY, 0)
}
// Create creates the named file, overwriting it if it already exists.
func Create(name string) (*File, error) {
return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
}
// Read reads up to len(b) bytes from the File. It returns the number of bytes
// read and any error encountered. At end of file, Read returns 0, io.EOF.
func (f *File) Read(b []byte) (n int, err error) {
n, err = f.handle.Read(b)
if err != nil && err != io.EOF {
err = &PathError{"read", f.name, err}
}
return
}
// ReadAt reads up to len(b) bytes from the File at the given absolute offset.
// It returns the number of bytes read and any error encountered, possible io.EOF.
// At end of file, Read returns 0, io.EOF.
func (f *File) ReadAt(b []byte, offset int64) (n int, err error) {
n, err = f.handle.ReadAt(b, offset)
if err != nil && err != io.EOF {
err = &PathError{"readat", f.name, err}
}
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 (f *File) Write(b []byte) (n int, err error) {
n, err = f.handle.Write(b)
if err != nil {
err = &PathError{"write", f.name, err}
}
return
}
// WriteString is like Write, but writes the contents of string s rather than a
// slice of bytes.
func (f *File) WriteString(s string) (n int, err error) {
return f.Write([]byte(s))
}
func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
return 0, ErrNotImplemented
}
// Close closes the File, rendering it unusable for I/O.
func (f *File) Close() (err error) {
err = f.handle.Close()
if err != nil {
err = &PathError{"close", f.name, err}
}
return
}
// Readdir is a stub, not yet implemented
func (f *File) Readdir(n int) ([]FileInfo, error) {
return nil, &PathError{"readdir", f.name, ErrNotImplemented}
}
// Readdirnames is a stub, not yet implemented
func (f *File) Readdirnames(n int) (names []string, err error) {
return nil, &PathError{"readdirnames", f.name, ErrNotImplemented}
}
// Seek is a stub, not yet implemented
func (f *File) Seek(offset int64, whence int) (ret int64, err error) {
return 0, &PathError{"seek", f.name, ErrNotImplemented}
}
// Stat is a stub, not yet implemented
func (f *File) Stat() (FileInfo, error) {
return nil, &PathError{"stat", f.name, ErrNotImplemented}
}
func (f *File) SyscallConn() (syscall.RawConn, error) {
return nil, ErrNotImplemented
}
// Fd returns the file handle referencing the open file.
func (f *File) Fd() uintptr {
panic("unimplemented: os.file.Fd()")
}
// Truncate is a stub, not yet implemented
func (f *File) Truncate(size int64) error {
return &PathError{"truncate", f.name, ErrNotImplemented}
}
// PathError records an error and the operation and file path that caused it.
// TODO: PathError moved to io/fs in go 1.16 and left an alias in os/errors.go.
// Do the same once we drop support for go 1.15.
type PathError struct {
Op string
Path string
Err error
}
func (e *PathError) Error() string {
return e.Op + " " + e.Path + ": " + e.Err.Error()
}
func (e *PathError) Unwrap() error {
return e.Err
}
// LinkError records an error during a link or symlink or rename system call and
// the paths that caused it.
type LinkError struct {
Op string
Old string
New string
Err error
}
func (e *LinkError) Error() string {
return e.Op + " " + e.Old + " " + e.New + ": " + e.Err.Error()
}
func (e *LinkError) Unwrap() error {
return e.Err
}
const (
O_RDONLY int = syscall.O_RDONLY
O_WRONLY int = syscall.O_WRONLY
O_RDWR int = syscall.O_RDWR
O_APPEND int = syscall.O_APPEND
O_CREATE int = syscall.O_CREAT
O_EXCL int = syscall.O_EXCL
O_SYNC int = syscall.O_SYNC
O_TRUNC int = syscall.O_TRUNC
)
func Getwd() (string, error) {
return syscall.Getwd()
}
// Readlink is a stub (for now), always returning the string it was given
func Readlink(name string) (string, error) {
return name, nil
}
// TempDir returns the default directory to use for temporary files.
//
// On Unix systems, it returns $TMPDIR if non-empty, else /tmp.
// On Windows, it uses GetTempPath, returning the first non-empty
// value from %TMP%, %TEMP%, %USERPROFILE%, or the Windows directory.
//
// The directory is neither guaranteed to exist nor have accessible
// permissions.
func TempDir() string {
return tempDir()
}