mozilla-central/third_party/rust/fuchsia-zircon/src/handle.rs

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use {Port, Rights, Signals, Status, Time, WaitAsyncOpts, ok, sys};
use std::marker::PhantomData;
use std::mem;
/// An object representing a Zircon
///
/// Internally, it is represented as a 32-bit integer, but this wrapper enforces
/// strict ownership semantics. The `Drop` implementation closes the handle.
///
/// This type represents the most general reference to a kernel object, and can
/// be interconverted to and from more specific types. Those conversions are not
/// enforced in the type system; attempting to use them will result in errors
/// returned by the kernel. These conversions don't change the underlying
/// representation, but do change the type and thus what operations are available.
#[derive(Debug, Eq, PartialEq, Hash)]
pub struct Handle(sys::zx_handle_t);
impl AsHandleRef for Handle {
fn as_handle_ref(&self) -> HandleRef {
HandleRef { handle: self.0, phantom: Default::default() }
}
}
impl HandleBased for Handle {}
impl Drop for Handle {
fn drop(&mut self) {
if self.0 != sys::ZX_HANDLE_INVALID {
unsafe { sys::zx_handle_close(self.0) };
}
}
}
impl Handle {
/// Initialize a handle backed by ZX_HANDLE_INVALID, the only safe non-handle.
pub fn invalid() -> Handle {
Handle(sys::ZX_HANDLE_INVALID)
}
/// If a raw handle is obtained from some other source, this method converts
/// it into a type-safe owned handle.
pub unsafe fn from_raw(raw: sys::zx_handle_t) -> Handle {
Handle(raw)
}
pub fn is_invalid(&self) -> bool {
self.0 == sys::ZX_HANDLE_INVALID
}
pub fn replace(self, rights: Rights) -> Result<Handle, Status> {
let handle = self.0;
let mut out = 0;
let status = unsafe { sys::zx_handle_replace(handle, rights.bits(), &mut out) };
ok(status).map(|()| Handle(out))
}
}
/// A borrowed reference to a `Handle`.
///
/// Mostly useful as part of a `WaitItem`.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct HandleRef<'a> {
handle: sys::zx_handle_t,
phantom: PhantomData<&'a sys::zx_handle_t>,
}
impl<'a> HandleRef<'a> {
pub fn raw_handle(&self) -> sys::zx_handle_t {
self.handle
}
pub fn duplicate(&self, rights: Rights) -> Result<Handle, Status> {
let handle = self.handle;
let mut out = 0;
let status = unsafe { sys::zx_handle_duplicate(handle, rights.bits(), &mut out) };
ok(status).map(|()| Handle(out))
}
pub fn signal(&self, clear_mask: Signals, set_mask: Signals) -> Result<(), Status> {
let handle = self.handle;
let status = unsafe { sys::zx_object_signal(handle, clear_mask.bits(), set_mask.bits()) };
ok(status)
}
pub fn wait(&self, signals: Signals, deadline: Time) -> Result<Signals, Status> {
let handle = self.handle;
let mut pending = Signals::empty().bits();
let status = unsafe {
sys::zx_object_wait_one(handle, signals.bits(), deadline.nanos(), &mut pending)
};
ok(status).map(|()| Signals::from_bits_truncate(pending))
}
pub fn wait_async(&self, port: &Port, key: u64, signals: Signals, options: WaitAsyncOpts)
-> Result<(), Status>
{
let handle = self.handle;
let status = unsafe {
sys::zx_object_wait_async(
handle, port.raw_handle(), key, signals.bits(), options as u32)
};
ok(status)
}
}
/// A trait to get a reference to the underlying handle of an object.
pub trait AsHandleRef {
/// Get a reference to the handle. One important use of such a reference is
/// for `object_wait_many`.
fn as_handle_ref(&self) -> HandleRef;
/// Interpret the reference as a raw handle (an integer type). Two distinct
/// handles will have different raw values (so it can perhaps be used as a
/// key in a data structure).
fn raw_handle(&self) -> sys::zx_handle_t {
self.as_handle_ref().raw_handle()
}
/// Set and clear userspace-accessible signal bits on an object. Wraps the
/// syscall.
fn signal_handle(&self, clear_mask: Signals, set_mask: Signals) -> Result<(), Status> {
self.as_handle_ref().signal(clear_mask, set_mask)
}
/// Waits on a handle. Wraps the
/// syscall.
fn wait_handle(&self, signals: Signals, deadline: Time) -> Result<Signals, Status> {
self.as_handle_ref().wait(signals, deadline)
}
/// Causes packet delivery on the given port when the object changes state and matches signals.
/// syscall.
fn wait_async_handle(&self, port: &Port, key: u64, signals: Signals, options: WaitAsyncOpts)
-> Result<(), Status>
{
self.as_handle_ref().wait_async(port, key, signals, options)
}
}
impl<'a> AsHandleRef for HandleRef<'a> {
fn as_handle_ref(&self) -> HandleRef { *self }
}
/// A trait implemented by all handle-based types.
///
/// Note: it is reasonable for user-defined objects wrapping a handle to implement
/// this trait. For example, a specific interface in some protocol might be
/// represented as a newtype of `Channel`, and implement the `as_handle_ref`
/// method and the `From<Handle>` trait to facilitate conversion from and to the
/// interface.
pub trait HandleBased: AsHandleRef + From<Handle> + Into<Handle> {
/// Duplicate a handle, possibly reducing the rights available. Wraps the
/// syscall.
fn duplicate_handle(&self, rights: Rights) -> Result<Self, Status> {
self.as_handle_ref().duplicate(rights).map(|handle| Self::from(handle))
}
/// Create a replacement for a handle, possibly reducing the rights available. This invalidates
/// the original handle. Wraps the
/// syscall.
fn replace_handle(self, rights: Rights) -> Result<Self, Status> {
<Self as Into<Handle>>::into(self)
.replace(rights).map(|handle| Self::from(handle))
}
/// Converts the value into its inner handle.
///
/// This is a convenience function which simply forwards to the `Into` trait.
fn into_handle(self) -> Handle {
self.into()
}
/// Converts the handle into it's raw representation.
///
/// The caller takes ownership over the raw handle, and must close or transfer it to avoid a handle leak.
fn into_raw(self) -> sys::zx_handle_t {
let h = self.into_handle();
let r = h.0;
mem::forget(h);
r
}
/// Creates an instance of this type from a handle.
///
/// This is a convenience function which simply forwards to the `From` trait.
fn from_handle(handle: Handle) -> Self {
Self::from(handle)
}
/// Creates an instance of another handle-based type from this value's inner handle.
fn into_handle_based<H: HandleBased>(self) -> H {
H::from_handle(self.into_handle())
}
/// Creates an instance of this type from the inner handle of another
/// handle-based type.
fn from_handle_based<H: HandleBased>(h: H) -> Self {
Self::from_handle(h.into_handle())
}
}
/// A trait implemented by all handles for objects which have a peer.
pub trait Peered: HandleBased {
/// Set and clear userspace-accessible signal bits on the object's peer. Wraps the
/// syscall.
fn signal_peer(&self, clear_mask: Signals, set_mask: Signals) -> Result<(), Status> {
let handle = self.as_handle_ref().handle;
let status = unsafe {
sys::zx_object_signal_peer(handle, clear_mask.bits(), set_mask.bits())
};
ok(status)
}
}
/// A trait implemented by all handles for objects which can have a cookie attached.
pub trait Cookied: HandleBased {
/// Get the cookie attached to this object, if any. Wraps the
/// syscall.
fn get_cookie(&self, scope: &HandleRef) -> Result<u64, Status> {
let handle = self.as_handle_ref().handle;
let mut cookie = 0;
let status = unsafe { sys::zx_object_get_cookie(handle, scope.handle, &mut cookie) };
ok(status).map(|()| cookie)
}
/// Attach an opaque cookie to this object with the given scope. The cookie may be read or
/// changed in future only with the same scope. Wraps the
/// syscall.
fn set_cookie(&self, scope: &HandleRef, cookie: u64) -> Result<(), Status> {
let handle = self.as_handle_ref().handle;
let status = unsafe { sys::zx_object_set_cookie(handle, scope.handle, cookie) };
ok(status)
}
}