use std::{
fs::File,
io,
os::windows::io::{AsRawHandle, FromRawHandle, IntoRawHandle, RawHandle},
path::Path,
process,
};
/// A handle represents an owned and valid Windows handle to a file-like
/// object.
///
/// When an owned handle is dropped, then the underlying raw handle is closed.
/// To get a borrowed handle, use `HandleRef`.
#[derive(Debug)]
pub struct Handle(File);
impl AsRawHandle for Handle {
fn as_raw_handle(&self) -> RawHandle {
self.0.as_raw_handle()
}
}
impl FromRawHandle for Handle {
unsafe fn from_raw_handle(handle: RawHandle) -> Handle {
Handle(File::from_raw_handle(handle))
}
}
impl IntoRawHandle for Handle {
fn into_raw_handle(self) -> RawHandle {
self.0.into_raw_handle()
}
}
impl Handle {
/// Create an owned handle to the given file.
///
/// When the returned handle is dropped, the file is closed.
///
/// Note that if the given file represents a handle to a directory, then
/// it is generally required that it have been opened with the
/// [`FILE_FLAG_BACKUP_SEMANTICS`] flag in order to use it in various
/// calls such as `information` or `typ`. To have this done automatically
/// for you, use the `from_path_any` constructor.
///
/// [`FILE_FLAG_BACKUP_SEMANTICS`]: https://docs.microsoft.com/en-us/windows/desktop/api/FileAPI/nf-fileapi-createfilea
pub fn from_file(file: File) -> Handle {
Handle(file)
}
/// Open a file to the given file path, and return an owned handle to that
/// file.
///
/// When the returned handle is dropped, the file is closed.
///
/// If there was a problem opening the file, then the corresponding error
/// is returned.
pub fn from_path<P: AsRef<Path>>(path: P) -> io::Result<Handle> {
Ok(Handle::from_file(File::open(path)?))
}
/// Like `from_path`, but supports opening directory handles as well.
///
/// If you use `from_path` on a directory, then subsequent queries using
/// that handle will fail.
pub fn from_path_any<P: AsRef<Path>>(path: P) -> io::Result<Handle> {
use std::fs::OpenOptions;
use std::os::windows::fs::OpenOptionsExt;
use windows_sys::Win32::Storage::FileSystem::FILE_FLAG_BACKUP_SEMANTICS;
let file = OpenOptions::new()
.read(true)
.custom_flags(FILE_FLAG_BACKUP_SEMANTICS)
.open(path)?;
Ok(Handle::from_file(file))
}
/// Return this handle as a standard `File` reference.
pub fn as_file(&self) -> &File {
&self.0
}
/// Return this handle as a standard `File` mutable reference.
pub fn as_file_mut(&mut self) -> &mut File {
&mut self.0
}
}
/// Represents a borrowed and valid Windows handle to a file-like object, such
/// as stdin/stdout/stderr or an actual file.
///
/// When a borrowed handle is dropped, then the underlying raw handle is
/// **not** closed. To get an owned handle, use `Handle`.
#[derive(Debug)]
pub struct HandleRef(HandleRefInner);
/// The representation of a HandleRef, on which we define a custom Drop impl
/// that avoids closing the underlying raw handle.
#[derive(Debug)]
struct HandleRefInner(Option<File>);
impl Drop for HandleRefInner {
fn drop(&mut self) {
self.0.take().unwrap().into_raw_handle();
}
}
impl AsRawHandle for HandleRef {
fn as_raw_handle(&self) -> RawHandle {
self.as_file().as_raw_handle()
}
}
impl Clone for HandleRef {
fn clone(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl HandleRef {
/// Create a borrowed handle to stdin.
///
/// When the returned handle is dropped, stdin is not closed.
pub fn stdin() -> HandleRef {
unsafe { HandleRef::from_raw_handle(io::stdin().as_raw_handle()) }
}
/// Create a handle to stdout.
///
/// When the returned handle is dropped, stdout is not closed.
pub fn stdout() -> HandleRef {
unsafe { HandleRef::from_raw_handle(io::stdout().as_raw_handle()) }
}
/// Create a handle to stderr.
///
/// When the returned handle is dropped, stderr is not closed.
pub fn stderr() -> HandleRef {
unsafe { HandleRef::from_raw_handle(io::stderr().as_raw_handle()) }
}
/// Create a borrowed handle to the given file.
///
/// When the returned handle is dropped, the file is not closed.
pub fn from_file(file: &File) -> HandleRef {
unsafe { HandleRef::from_raw_handle(file.as_raw_handle()) }
}
/// Create a borrowed handle from the given raw handle.
///
/// Note that unlike the `FromRawHandle` trait, this constructor does
/// **not** consume ownership of the given handle. That is, when the
/// borrowed handle created by this constructor is dropped, the underlying
/// handle will not be closed.
///
/// # Safety
///
/// This is unsafe because there is no guarantee that the given raw handle
/// is a valid handle. The caller must ensure this is true before invoking
/// this constructor.
pub unsafe fn from_raw_handle(handle: RawHandle) -> HandleRef {
HandleRef(HandleRefInner(Some(File::from_raw_handle(handle))))
}
/// Return this handle as a standard `File` reference.
pub fn as_file(&self) -> &File {
(self.0).0.as_ref().unwrap()
}
/// Return this handle as a standard `File` mutable reference.
pub fn as_file_mut(&mut self) -> &mut File {
(self.0).0.as_mut().unwrap()
}
}
/// Construct borrowed and valid Windows handles from file-like objects.
pub trait AsHandleRef {
/// A borrowed handle that wraps the raw handle of the `Self` object.
fn as_handle_ref(&self) -> HandleRef;
/// A convenience routine for extracting a `HandleRef` from `Self`, and
/// then extracting a raw handle from the `HandleRef`.
fn as_raw(&self) -> RawHandle {
self.as_handle_ref().as_raw_handle()
}
}
impl<'a, T: AsHandleRef> AsHandleRef for &'a T {
fn as_handle_ref(&self) -> HandleRef {
(**self).as_handle_ref()
}
}
impl AsHandleRef for Handle {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for HandleRef {
fn as_handle_ref(&self) -> HandleRef {
self.clone()
}
}
impl AsHandleRef for File {
fn as_handle_ref(&self) -> HandleRef {
HandleRef::from_file(self)
}
}
impl AsHandleRef for io::Stdin {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for io::Stdout {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for io::Stderr {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for process::ChildStdin {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for process::ChildStdout {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
impl AsHandleRef for process::ChildStderr {
fn as_handle_ref(&self) -> HandleRef {
unsafe { HandleRef::from_raw_handle(self.as_raw_handle()) }
}
}
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