patch os: File

internal/lib/os/file_unix.go

@@ -0,0 +1,199 @@
+// 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.
+
+//go:build unix || (js && wasm) || wasip1
+
+package os
+
+import (
+	"io/fs"
+	"runtime"
+)
+
+// Fd returns the integer Unix file descriptor referencing the open file.
+// If f is closed, the file descriptor becomes invalid.
+// If f is garbage collected, a finalizer may close the file descriptor,
+// making it invalid; see runtime.SetFinalizer for more information on when
+// a finalizer might be run. On Unix systems this will cause the SetDeadline
+// methods to stop working.
+// Because file descriptors can be reused, the returned file descriptor may
+// only be closed through the Close method of f, or by its finalizer during
+// garbage collection. Otherwise, during garbage collection the finalizer
+// may close an unrelated file descriptor with the same (reused) number.
+//
+// As an alternative, see the f.SyscallConn method.
+func (f *File) Fd() uintptr {
+	if f == nil {
+		return ^(uintptr(0))
+	}
+
+	return f.fd
+}
+
+// NewFile returns a new File with the given file descriptor and
+// name. The returned value will be nil if fd is not a valid file
+// descriptor. On Unix systems, if the file descriptor is in
+// non-blocking mode, NewFile will attempt to return a pollable File
+// (one for which the SetDeadline methods work).
+//
+// After passing it to NewFile, fd may become invalid under the same
+// conditions described in the comments of the Fd method, and the same
+// constraints apply.
+func NewFile(fd uintptr, name string) *File {
+	return &File{fd: fd, name: name}
+}
+
+/* TODO(xsw):
+// NewFile returns a new File with the given file descriptor and
+// name. The returned value will be nil if fd is not a valid file
+// descriptor. On Unix systems, if the file descriptor is in
+// non-blocking mode, NewFile will attempt to return a pollable File
+// (one for which the SetDeadline methods work).
+//
+// After passing it to NewFile, fd may become invalid under the same
+// conditions described in the comments of the Fd method, and the same
+// constraints apply.
+func NewFile(fd uintptr, name string) *File {
+	fdi := int(fd)
+	if fdi < 0 {
+		return nil
+	}
+
+	kind := kindNewFile
+	appendMode := false
+	if flags, err := unix.Fcntl(fdi, syscall.F_GETFL, 0); err == nil {
+		if unix.HasNonblockFlag(flags) {
+			kind = kindNonBlock
+		}
+		appendMode = flags&syscall.O_APPEND != 0
+	}
+	f := newFile(fdi, name, kind)
+	f.appendMode = appendMode
+	return f
+}
+
+// net_newUnixFile is a hidden entry point called by net.conn.File.
+// This is used so that a nonblocking network connection will become
+// blocking if code calls the Fd method. We don't want that for direct
+// calls to NewFile: passing a nonblocking descriptor to NewFile should
+// remain nonblocking if you get it back using Fd. But for net.conn.File
+// the call to NewFile is hidden from the user. Historically in that case
+// the Fd method has returned a blocking descriptor, and we want to
+// retain that behavior because existing code expects it and depends on it.
+//
+//-go:linkname net_newUnixFile net.newUnixFile
+func net_newUnixFile(fd int, name string) *File {
+	if fd < 0 {
+		panic("invalid FD")
+	}
+
+	f := newFile(fd, name, kindNonBlock)
+	f.nonblock = true // tell Fd to return blocking descriptor
+	return f
+}
+*/
+
+// newFileKind describes the kind of file to newFile.
+type newFileKind int
+
+const (
+	// kindNewFile means that the descriptor was passed to us via NewFile.
+	kindNewFile newFileKind = iota
+	// kindOpenFile means that the descriptor was opened using
+	// Open, Create, or OpenFile (without O_NONBLOCK).
+	kindOpenFile
+	// kindPipe means that the descriptor was opened using Pipe.
+	kindPipe
+	// kindNonBlock means that the descriptor is already in
+	// non-blocking mode.
+	kindNonBlock
+	// kindNoPoll means that we should not put the descriptor into
+	// non-blocking mode, because we know it is not a pipe or FIFO.
+	// Used by openFdAt for directories.
+	kindNoPoll
+)
+
+// TODO(xsw):
+// func sigpipe() // implemented in package runtime
+
+// epipecheck raises SIGPIPE if we get an EPIPE error on standard
+// output or standard error. See the SIGPIPE docs in os/signal, and
+// issue 11845.
+func epipecheck(file *File, e error) {
+	/* TODO(xsw):
+	if e == syscall.EPIPE && file.stdoutOrErr {
+		sigpipe()
+	}
+	*/
+	panic("todo: os.epipecheck")
+}
+
+// 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"
+
+// openFileNolog is the Unix implementation of OpenFile.
+// Changes here should be reflected in openFdAt, if relevant.
+func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
+	panic("todo: os.openFileNolog")
+}
+
+func tempDir() string {
+	dir := Getenv("TMPDIR")
+	if dir == "" {
+		if runtime.GOOS == "android" {
+			dir = "/data/local/tmp"
+		} else {
+			dir = "/tmp"
+		}
+	}
+	return dir
+}
+
+type unixDirent struct {
+	parent string
+	name   string
+	typ    FileMode
+	info   FileInfo
+}
+
+func (d *unixDirent) Name() string   { return d.name }
+func (d *unixDirent) IsDir() bool    { return d.typ.IsDir() }
+func (d *unixDirent) Type() FileMode { return d.typ }
+
+func (d *unixDirent) Info() (FileInfo, error) {
+	/* TODO(xsw):
+	if d.info != nil {
+		return d.info, nil
+	}
+	return lstat(d.parent + "/" + d.name)
+	*/
+	panic("todo: os.unixDirent.Info")
+}
+
+func (d *unixDirent) String() string {
+	return fs.FormatDirEntry(d)
+}
+
+/* TODO(xsw):
+func newUnixDirent(parent, name string, typ FileMode) (DirEntry, error) {
+	ude := &unixDirent{
+		parent: parent,
+		name:   name,
+		typ:    typ,
+	}
+	if typ != ^FileMode(0) && !testingForceReadDirLstat {
+		return ude, nil
+	}
+
+	info, err := lstat(parent + "/" + name)
+	if err != nil {
+		return nil, err
+	}
+
+	ude.typ = info.Mode().Type()
+	ude.info = info
+	return ude, nil
+}
+*/