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Rollup merge of #152531 - cyrgani:pm-yet-another-cleanup, r=petrochenkov

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`proc_macro::bridge`: simplify `ExecutionStrategy` and `DispatcherTrait`

Also includes another tiny cleanup (functions can only have one return type).
This commit is contained in:
Jonathan Brouwer 2026-02-14 18:55:36 +01:00 • committed by GitHub
commit 8a03b5f3ec
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GPG key ID: B5690EEEBB952194
5 changed files with 68 additions and 124 deletions
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2
library/proc_macro/src/bridge/client.rs
View file

@ -98,7 +98,7 @@ pub(crate) use super::symbol::Symbol;
macro_rules! define_client_side {
(
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
) => {
impl Methods {
$(pub(crate) fn $method($($arg: $arg_ty),*) $(-> $ret_ty)? {

2
library/proc_macro/src/bridge/mod.rs
View file

@ -133,7 +133,7 @@ impl !Sync for BridgeConfig<'_> {}
macro_rules! declare_tags {
(
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
) => {
#[allow(non_camel_case_types)]
pub(super) enum ApiTags {

155
library/proc_macro/src/bridge/server.rs
View file

@ -1,7 +1,7 @@
//! Server-side traits.
use std::cell::Cell;
use std::marker::PhantomData;
use std::sync::mpsc;
use super::*;
@ -53,14 +53,9 @@ impl<S: Server> Decode<'_, '_, HandleStore<S>> for MarkedSpan<S> {
}
}
struct Dispatcher<S: Server> {
handle_store: HandleStore<S>,
server: S,
}
macro_rules! define_server {
(
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
) => {
pub trait Server {
type TokenStream: 'static + Clone + Default;
@ -81,16 +76,17 @@ macro_rules! define_server {
}
with_api!(define_server, Self::TokenStream, Self::Span, Self::Symbol);
// FIXME(eddyb) `pub` only for `ExecutionStrategy` below.
pub struct Dispatcher<S: Server> {
handle_store: HandleStore<S>,
server: S,
}
macro_rules! define_dispatcher {
(
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
$(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
) => {
// FIXME(eddyb) `pub` only for `ExecutionStrategy` below.
pub trait DispatcherTrait {
fn dispatch(&mut self, buf: Buffer) -> Buffer;
}
impl<S: Server> DispatcherTrait for Dispatcher<S> {
impl<S: Server> Dispatcher<S> {
fn dispatch(&mut self, mut buf: Buffer) -> Buffer {
let Dispatcher { handle_store, server } = self;
@ -100,9 +96,7 @@ macro_rules! define_dispatcher {
let mut call_method = || {
$(let $arg = <$arg_ty>::decode(&mut reader, handle_store).unmark();)*
let r = server.$method($($arg),*);
$(
let r: $ret_ty = Mark::mark(r);
)*
$(let r: $ret_ty = Mark::mark(r);)?
r
};
// HACK(eddyb) don't use `panic::catch_unwind` in a panic.
@ -127,10 +121,13 @@ macro_rules! define_dispatcher {
}
with_api!(define_dispatcher, MarkedTokenStream<S>, MarkedSpan<S>, MarkedSymbol<S>);
// This trait is currently only implemented and used once, inside of this crate.
// We keep it public to allow implementing more complex execution strategies in
// the future, such as wasm proc-macros.
pub trait ExecutionStrategy {
fn run_bridge_and_client(
&self,
dispatcher: &mut impl DispatcherTrait,
dispatcher: &mut Dispatcher<impl Server>,
input: Buffer,
run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
force_show_panics: bool,
@ -169,110 +166,78 @@ impl Drop for RunningSameThreadGuard {
}
}
pub struct MaybeCrossThread<P> {
cross_thread: bool,
marker: PhantomData<P>,
pub struct MaybeCrossThread {
pub cross_thread: bool,
}
impl<P> MaybeCrossThread<P> {
pub const fn new(cross_thread: bool) -> Self {
MaybeCrossThread { cross_thread, marker: PhantomData }
}
}
pub const SAME_THREAD: MaybeCrossThread = MaybeCrossThread { cross_thread: false };
pub const CROSS_THREAD: MaybeCrossThread = MaybeCrossThread { cross_thread: true };
impl<P> ExecutionStrategy for MaybeCrossThread<P>
where
P: MessagePipe<Buffer> + Send + 'static,
{
impl ExecutionStrategy for MaybeCrossThread {
fn run_bridge_and_client(
&self,
dispatcher: &mut impl DispatcherTrait,
dispatcher: &mut Dispatcher<impl Server>,
input: Buffer,
run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
force_show_panics: bool,
) -> Buffer {
if self.cross_thread || ALREADY_RUNNING_SAME_THREAD.get() {
<CrossThread<P>>::new().run_bridge_and_client(
dispatcher,
input,
run_client,
force_show_panics,
)
let (mut server, mut client) = MessagePipe::new();
let join_handle = thread::spawn(move || {
let mut dispatch = |b: Buffer| -> Buffer {
client.send(b);
client.recv().expect("server died while client waiting for reply")
};
run_client(BridgeConfig {
input,
dispatch: (&mut dispatch).into(),
force_show_panics,
})
});
while let Some(b) = server.recv() {
server.send(dispatcher.dispatch(b));
}
join_handle.join().unwrap()
} else {
SameThread.run_bridge_and_client(dispatcher, input, run_client, force_show_panics)
}
}
}
let _guard = RunningSameThreadGuard::new();
pub struct SameThread;
impl ExecutionStrategy for SameThread {
fn run_bridge_and_client(
&self,
dispatcher: &mut impl DispatcherTrait,
input: Buffer,
run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
force_show_panics: bool,
) -> Buffer {
let _guard = RunningSameThreadGuard::new();
let mut dispatch = |buf| dispatcher.dispatch(buf);
run_client(BridgeConfig { input, dispatch: (&mut dispatch).into(), force_show_panics })
}
}
pub struct CrossThread<P>(PhantomData<P>);
impl<P> CrossThread<P> {
pub const fn new() -> Self {
CrossThread(PhantomData)
}
}
impl<P> ExecutionStrategy for CrossThread<P>
where
P: MessagePipe<Buffer> + Send + 'static,
{
fn run_bridge_and_client(
&self,
dispatcher: &mut impl DispatcherTrait,
input: Buffer,
run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
force_show_panics: bool,
) -> Buffer {
let (mut server, mut client) = P::new();
let join_handle = thread::spawn(move || {
let mut dispatch = |b: Buffer| -> Buffer {
client.send(b);
client.recv().expect("server died while client waiting for reply")
};
let mut dispatch = |buf| dispatcher.dispatch(buf);
run_client(BridgeConfig { input, dispatch: (&mut dispatch).into(), force_show_panics })
});
while let Some(b) = server.recv() {
server.send(dispatcher.dispatch(b));
}
join_handle.join().unwrap()
}
}
/// A message pipe used for communicating between server and client threads.
pub trait MessagePipe<T>: Sized {
struct MessagePipe<T> {
tx: mpsc::SyncSender<T>,
rx: mpsc::Receiver<T>,
}
impl<T> MessagePipe<T> {
/// Creates a new pair of endpoints for the message pipe.
fn new() -> (Self, Self);
fn new() -> (Self, Self) {
let (tx1, rx1) = mpsc::sync_channel(1);
let (tx2, rx2) = mpsc::sync_channel(1);
(MessagePipe { tx: tx1, rx: rx2 }, MessagePipe { tx: tx2, rx: rx1 })
}
/// Send a message to the other endpoint of this pipe.
fn send(&mut self, value: T);
fn send(&mut self, value: T) {
self.tx.send(value).unwrap();
}
/// Receive a message from the other endpoint of this pipe.
///
/// Returns `None` if the other end of the pipe has been destroyed, and no
/// message was received.
fn recv(&mut self) -> Option<T>;
fn recv(&mut self) -> Option<T> {
self.rx.recv().ok()
}
}
fn run_server<