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//! Client-side types.
use super::*;
macro_rules! define_handles {
(
'owned: $($oty:ident,)*
'interned: $($ity:ident,)*
) => {
#[repr(C)]
#[allow(non_snake_case)]
pub struct HandleCounters {
$($oty: AtomicUsize,)*
$($ity: AtomicUsize,)*
}
impl HandleCounters {
// FIXME(#53451) public to work around `Cannot create local mono-item` ICE.
pub extern "C" fn get() -> &'static Self {
static COUNTERS: HandleCounters = HandleCounters {
$($oty: AtomicUsize::new(1),)*
$($ity: AtomicUsize::new(1),)*
};
&COUNTERS
}
}
// FIXME(eddyb) generate the definition of `HandleStore` in `server.rs`.
#[repr(C)]
#[allow(non_snake_case)]
pub(super) struct HandleStore<S: server::Types> {
$($oty: handle::OwnedStore<S::$oty>,)*
$($ity: handle::InternedStore<S::$ity>,)*
}
impl<S: server::Types> HandleStore<S> {
pub(super) fn new(handle_counters: &'static HandleCounters) -> Self {
HandleStore {
$($oty: handle::OwnedStore::new(&handle_counters.$oty),)*
$($ity: handle::InternedStore::new(&handle_counters.$ity),)*
}
}
}
$(
#[repr(C)]
pub(crate) struct $oty(handle::Handle);
impl !Send for $oty {}
impl !Sync for $oty {}
// Forward `Drop::drop` to the inherent `drop` method.
impl Drop for $oty {
fn drop(&mut self) {
$oty(self.0).drop();
}
}
impl<S> Encode<S> for $oty {
fn encode(self, w: &mut Writer, s: &mut S) {
let handle = self.0;
mem::forget(self);
handle.encode(w, s);
}
}
impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
for Marked<S::$oty, $oty>
{
fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
s.$oty.take(handle::Handle::decode(r, &mut ()))
}
}
impl<S> Encode<S> for &$oty {
fn encode(self, w: &mut Writer, s: &mut S) {
self.0.encode(w, s);
}
}
impl<S: server::Types> Decode<'_, 's, HandleStore<server::MarkedTypes<S>>>
for &'s Marked<S::$oty, $oty>
{
fn decode(r: &mut Reader<'_>, s: &'s HandleStore<server::MarkedTypes<S>>) -> Self {
&s.$oty[handle::Handle::decode(r, &mut ())]
}
}
impl<S> Encode<S> for &mut $oty {
fn encode(self, w: &mut Writer, s: &mut S) {
self.0.encode(w, s);
}
}
impl<S: server::Types> DecodeMut<'_, 's, HandleStore<server::MarkedTypes<S>>>
for &'s mut Marked<S::$oty, $oty>
{
fn decode(
r: &mut Reader<'_>,
s: &'s mut HandleStore<server::MarkedTypes<S>>
) -> Self {
&mut s.$oty[handle::Handle::decode(r, &mut ())]
}
}
impl<S: server::Types> Encode<HandleStore<server::MarkedTypes<S>>>
for Marked<S::$oty, $oty>
{
fn encode(self, w: &mut Writer, s: &mut HandleStore<server::MarkedTypes<S>>) {
s.$oty.alloc(self).encode(w, s);
}
}
impl<S> DecodeMut<'_, '_, S> for $oty {
fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
$oty(handle::Handle::decode(r, s))
}
}
)*
$(
#[repr(C)]
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
pub(crate) struct $ity(handle::Handle);
impl !Send for $ity {}
impl !Sync for $ity {}
impl<S> Encode<S> for $ity {
fn encode(self, w: &mut Writer, s: &mut S) {
self.0.encode(w, s);
}
}
impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
for Marked<S::$ity, $ity>
{
fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
s.$ity.copy(handle::Handle::decode(r, &mut ()))
}
}
impl<S: server::Types> Encode<HandleStore<server::MarkedTypes<S>>>
for Marked<S::$ity, $ity>
{
fn encode(self, w: &mut Writer, s: &mut HandleStore<server::MarkedTypes<S>>) {
s.$ity.alloc(self).encode(w, s);
}
}
impl<S> DecodeMut<'_, '_, S> for $ity {
fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
$ity(handle::Handle::decode(r, s))
}
}
)*
}
}
define_handles! {
'owned:
TokenStream,
TokenStreamBuilder,
TokenStreamIter,
Group,
Literal,
SourceFile,
MultiSpan,
Diagnostic,
'interned:
Punct,
Ident,
Span,
}
// FIXME(eddyb) generate these impls by pattern-matching on the
// names of methods - also could use the presence of `fn drop`
// to distinguish between 'owned and 'interned, above.
// Alternatively, special 'modes" could be listed of types in with_api
// instead of pattern matching on methods, here and in server decl.
impl Clone for TokenStream {
fn clone(&self) -> Self {
self.clone()
}
}
impl Clone for TokenStreamIter {
fn clone(&self) -> Self {
self.clone()
}
}
impl Clone for Group {
fn clone(&self) -> Self {
self.clone()
}
}
impl Clone for Literal {
fn clone(&self) -> Self {
self.clone()
}
}
// FIXME(eddyb) `Literal` should not expose internal `Debug` impls.
impl fmt::Debug for Literal {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(&self.debug())
}
}
impl Clone for SourceFile {
fn clone(&self) -> Self {
self.clone()
}
}
impl fmt::Debug for Span {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(&self.debug())
}
}
macro_rules! define_client_side {
($($name:ident {
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
}),* $(,)?) => {
$(impl $name {
$(pub(crate) fn $method($($arg: $arg_ty),*) $(-> $ret_ty)* {
Bridge::with(|bridge| {
let mut b = bridge.cached_buffer.take();
b.clear();
api_tags::Method::$name(api_tags::$name::$method).encode(&mut b, &mut ());
reverse_encode!(b; $($arg),*);
b = bridge.dispatch.call(b);
let r = Result::<_, PanicMessage>::decode(&mut &b[..], &mut ());
bridge.cached_buffer = b;
r.unwrap_or_else(|e| panic::resume_unwind(e.into()))
})
})*
})*
}
}
with_api!(self, self, define_client_side);
enum BridgeState<'a> {
/// No server is currently connected to this client.
NotConnected,
/// A server is connected and available for requests.
Connected(Bridge<'a>),
/// Access to the bridge is being exclusively acquired
/// (e.g., during `BridgeState::with`).
InUse,
}
enum BridgeStateL {}
impl<'a> scoped_cell::ApplyL<'a> for BridgeStateL {
type Out = BridgeState<'a>;
}
thread_local! {
static BRIDGE_STATE: scoped_cell::ScopedCell<BridgeStateL> =
scoped_cell::ScopedCell::new(BridgeState::NotConnected);
}
impl BridgeState<'_> {
/// Take exclusive control of the thread-local
/// `BridgeState`, and pass it to `f`, mutably.
/// The state will be restored after `f` exits, even
/// by panic, including modifications made to it by `f`.
///
/// N.B., while `f` is running, the thread-local state
/// is `BridgeState::InUse`.
fn with<R>(f: impl FnOnce(&mut BridgeState<'_>) -> R) -> R {
BRIDGE_STATE.with(|state| {
state.replace(BridgeState::InUse, |mut state| {
// FIXME(#52812) pass `f` directly to `replace` when `RefMutL` is gone
f(&mut *state)
})
})
}
}
impl Bridge<'_> {
fn enter<R>(self, f: impl FnOnce() -> R) -> R {
// Hide the default panic output within `proc_macro` expansions.
// NB. the server can't do this because it may use a different libstd.
static HIDE_PANICS_DURING_EXPANSION: Once = Once::new();
HIDE_PANICS_DURING_EXPANSION.call_once(|| {
let prev = panic::take_hook();
panic::set_hook(Box::new(move |info| {
let hide = BridgeState::with(|state| match state {
BridgeState::NotConnected => false,
BridgeState::Connected(_) | BridgeState::InUse => true,
});
if !hide {
prev(info)
}
}));
});
BRIDGE_STATE.with(|state| state.set(BridgeState::Connected(self), f))
}
fn with<R>(f: impl FnOnce(&mut Bridge<'_>) -> R) -> R {
BridgeState::with(|state| match state {
BridgeState::NotConnected => {
panic!("procedural macro API is used outside of a procedural macro");
}
BridgeState::InUse => {
panic!("procedural macro API is used while it's already in use");
}
BridgeState::Connected(bridge) => f(bridge),
})
}
}
/// A client-side "global object" (usually a function pointer),
/// which may be using a different `proc_macro` from the one
/// used by the server, but can be interacted with compatibly.
///
/// N.B., `F` must have FFI-friendly memory layout (e.g., a pointer).
/// The call ABI of function pointers used for `F` doesn't
/// need to match between server and client, since it's only
/// passed between them and (eventually) called by the client.
#[repr(C)]
#[derive(Copy, Clone)]
pub struct Client<F> {
pub(super) get_handle_counters: extern "C" fn() -> &'static HandleCounters,
pub(super) run: extern "C" fn(Bridge<'_>, F) -> Buffer<u8>,
pub(super) f: F,
}
// FIXME(#53451) public to work around `Cannot create local mono-item` ICE,
// affecting not only the function itself, but also the `BridgeState` `thread_local!`.
pub extern "C" fn __run_expand1(
mut bridge: Bridge<'_>,
f: fn(crate::TokenStream) -> crate::TokenStream,
) -> Buffer<u8> {
// The initial `cached_buffer` contains the input.
let mut b = bridge.cached_buffer.take();
panic::catch_unwind(panic::AssertUnwindSafe(|| {
bridge.enter(|| {
let reader = &mut &b[..];
let input = TokenStream::decode(reader, &mut ());
// Put the `cached_buffer` back in the `Bridge`, for requests.
Bridge::with(|bridge| bridge.cached_buffer = b.take());
let output = f(crate::TokenStream(input)).0;
// Take the `cached_buffer` back out, for the output value.
b = Bridge::with(|bridge| bridge.cached_buffer.take());
// HACK(eddyb) Separate encoding a success value (`Ok(output)`)
// from encoding a panic (`Err(e: PanicMessage)`) to avoid
// having handles outside the `bridge.enter(|| ...)` scope, and
// to catch panics that could happen while encoding the success.
//
// Note that panics should be impossible beyond this point, but
// this is defensively trying to avoid any accidental panicking
// reaching the `extern "C"` (which should `abort` but may not
// at the moment, so this is also potentially preventing UB).
b.clear();
Ok::<_, ()>(output).encode(&mut b, &mut ());
})
}))
.map_err(PanicMessage::from)
.unwrap_or_else(|e| {
b.clear();
Err::<(), _>(e).encode(&mut b, &mut ());
});
b
}
impl Client<fn(crate::TokenStream) -> crate::TokenStream> {
pub const fn expand1(f: fn(crate::TokenStream) -> crate::TokenStream) -> Self {
Client {
get_handle_counters: HandleCounters::get,
run: __run_expand1,
f,
}
}
}
// FIXME(#53451) public to work around `Cannot create local mono-item` ICE,
// affecting not only the function itself, but also the `BridgeState` `thread_local!`.
pub extern "C" fn __run_expand2(
mut bridge: Bridge<'_>,
f: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream,
) -> Buffer<u8> {
// The initial `cached_buffer` contains the input.
let mut b = bridge.cached_buffer.take();
panic::catch_unwind(panic::AssertUnwindSafe(|| {
bridge.enter(|| {
let reader = &mut &b[..];
let input = TokenStream::decode(reader, &mut ());
let input2 = TokenStream::decode(reader, &mut ());
// Put the `cached_buffer` back in the `Bridge`, for requests.
Bridge::with(|bridge| bridge.cached_buffer = b.take());
let output = f(crate::TokenStream(input), crate::TokenStream(input2)).0;
// Take the `cached_buffer` back out, for the output value.
b = Bridge::with(|bridge| bridge.cached_buffer.take());
// HACK(eddyb) Separate encoding a success value (`Ok(output)`)
// from encoding a panic (`Err(e: PanicMessage)`) to avoid
// having handles outside the `bridge.enter(|| ...)` scope, and
// to catch panics that could happen while encoding the success.
//
// Note that panics should be impossible beyond this point, but
// this is defensively trying to avoid any accidental panicking
// reaching the `extern "C"` (which should `abort` but may not
// at the moment, so this is also potentially preventing UB).
b.clear();
Ok::<_, ()>(output).encode(&mut b, &mut ());
})
}))
.map_err(PanicMessage::from)
.unwrap_or_else(|e| {
b.clear();
Err::<(), _>(e).encode(&mut b, &mut ());
});
b
}
impl Client<fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream> {
pub const fn expand2(
f: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream
) -> Self {
Client {
get_handle_counters: HandleCounters::get,
run: __run_expand2,
f,
}
}
}
#[repr(C)]
#[derive(Copy, Clone)]
pub enum ProcMacro {
CustomDerive {
trait_name: &'static str,
attributes: &'static [&'static str],
client: Client<fn(crate::TokenStream) -> crate::TokenStream>,
},
Attr {
name: &'static str,
client: Client<fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream>,
},
Bang {
name: &'static str,
client: Client<fn(crate::TokenStream) -> crate::TokenStream>,
},
}
impl ProcMacro {
pub const fn custom_derive(
trait_name: &'static str,
attributes: &'static [&'static str],
expand: fn(crate::TokenStream) -> crate::TokenStream,
) -> Self {
ProcMacro::CustomDerive {
trait_name,
attributes,
client: Client::expand1(expand),
}
}
pub const fn attr(
name: &'static str,
expand: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream,
) -> Self {
ProcMacro::Attr {
name,
client: Client::expand2(expand),
}
}
pub const fn bang(
name: &'static str,
expand: fn(crate::TokenStream) -> crate::TokenStream
) -> Self {
ProcMacro::Bang {
name,
client: Client::expand1(expand),
}
}
}
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