Externally defined Init/Idle

CHANGELOG.md

@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 
 - CI changelog entry enforcer
+- Support for externally defined #[init] and #[idle]
 
 ## [v1.0.0] - 2021-12-25
 

examples/extern_idle.rs

@@ -0,0 +1,40 @@
+//! examples/extern_idle
+
+#[mock::app(parse_binds, dispatchers = [UART1])]
+mod app {
+    // idle externally implemented
+    use crate::{bar, foo};
+
+    #[shared]
+    struct Shared {
+        a: u32,
+    }
+
+    #[local]
+    struct Local {}
+
+    #[init]
+    fn init(_: init::Context) -> (Shared, Local, init::Monotonics) {}
+
+    extern "Rust" {
+        // Software task
+        #[task(shared = [a], priority = 2)]
+        fn foo(_: foo::Context, _: u32);
+
+        // Hardware task
+        #[task(binds = UART0, shared = [a], priority = 2)]
+        // #[inline(always)] // would be rejected
+        fn bar(_: bar::Context);
+
+        // Externally defined idle task
+        #[idle()]
+        fn idle(_: idle::Context) -> !;
+    }
+}
+
+// The actual functions to dispatch are
+// defined outside of the mod `app`.
+//
+// fn foo(_: foo::Context, _: u32) {}
+// fn bar(_: bar::Context, _: u32) {}
+// fn idle(_: idle::Context) -> ! {}

examples/extern_init.rs

@@ -0,0 +1,41 @@
+//! examples/extern_init
+
+#[mock::app(parse_binds, dispatchers = [UART1])]
+mod app {
+    // init externally implemented
+    use crate::{bar, foo, idle, init};
+
+    #[shared]
+    struct Shared {
+        a: u32,
+    }
+
+    #[local]
+    struct Local {}
+
+    #[idle]
+    fn idle(_: idle::Context) -> ! {}
+
+    extern "Rust" {
+
+        // Externally defined init
+        #[init]
+        fn init(_: init::Context) -> (Shared, Local, init::Monotonics);
+
+        // Software task
+        #[task(shared = [a], priority = 2)]
+        fn foo(_: foo::Context, _: u32);
+
+        // Hardware task
+        #[task(binds = UART0, shared = [a], priority = 2)]
+        //#[inline(always)] // would be rejected
+        fn bar(_: bar::Context);
+    }
+}
+
+// The actual functions to dispatch are
+// defined outside of the mod `app`.
+//
+// fn foo(_: foo::Context, _: u32) {}
+// fn bar(_: bar::Context, _: u32) {}
+// fn init(_: init::Context) -> (Shared, Local, init::Monotonics) {}

src/ast.rs

@@ -90,6 +90,9 @@ pub struct Init {
 
     /// The name of the user provided local resources struct
     pub user_local_struct: Ident,
+
+    /// The task is declared externally
+    pub is_extern: bool,
 }
 
 /// `init` context metadata
@@ -126,6 +129,9 @@ pub struct Idle {
 
     /// The statements that make up this `idle` function
     pub stmts: Vec<Stmt>,
+
+    /// The task is declared externally
+    pub is_extern: bool,
 }
 
 /// `idle` context metadata

src/parse/app.rs

@@ -383,7 +383,46 @@ impl App {
                     for item in mod_.items {
                         if let ForeignItem::Fn(mut item) = item {
                             let span = item.sig.ident.span();
+                            // Find externally defined #[init] tasks
                             if let Some(pos) = item
+                                .attrs
+                                .iter()
+                                .position(|attr| util::attr_eq(attr, "init"))
+                            {
+                                let args = InitArgs::parse(item.attrs.remove(pos).tokens)?;
+
+                                // If an init function already exists, error
+                                if init.is_some() {
+                                    return Err(parse::Error::new(
+                                        span,
+                                        "`#[init]` function must appear at most once",
+                                    ));
+                                }
+
+                                check_ident(&item.sig.ident)?;
+
+                                init = Some(Init::parse_foreign(args, item.clone())?);
+
+                                // Find externally defined #[idle] tasks
+                            } else if let Some(pos) = item
+                                .attrs
+                                .iter()
+                                .position(|attr| util::attr_eq(attr, "idle"))
+                            {
+                                let args = IdleArgs::parse(item.attrs.remove(pos).tokens)?;
+
+                                // If an idle function already exists, error
+                                if idle.is_some() {
+                                    return Err(parse::Error::new(
+                                        span,
+                                        "`#[idle]` function must appear at most once",
+                                    ));
+                                }
+
+                                check_ident(&item.sig.ident)?;
+
+                                idle = Some(Idle::parse_foreign(args, item.clone())?);
+                            } else if let Some(pos) = item
                                 .attrs
                                 .iter()
                                 .position(|attr| util::attr_eq(attr, "task"))
@@ -400,7 +439,7 @@ impl App {
                                 if item.attrs.len() != 1 {
                                     return Err(parse::Error::new(
                                         span,
-                                        "`extern` task required `#[task(..)]` attribute",
+                                        "`extern` tasks only supports one attribute: `#[task(..)]`",
                                     ));
                                 }
 
@@ -430,14 +469,10 @@ impl App {
                             } else {
                                 return Err(parse::Error::new(
                                     span,
-                                    "`extern` task required `#[task(..)]` attribute",
+                                    "`extern` task, init or idle must have either `#[task(..)]`,
+                                    `#[init(..)]` or `#[idle(..)]` attribute",
                                 ));
                             }
-                        } else {
-                            return Err(parse::Error::new(
-                                item.span(),
-                                "this item must live outside the `#[app]` module",
-                            ));
                         }
                     }
                 }

src/parse/hardware_task.rs

@@ -47,9 +47,6 @@ impl HardwareTask {
             ),
         ))
     }
-}
-
-impl HardwareTask {
     pub(crate) fn parse_foreign(
         args: HardwareTaskArgs,
         item: ForeignItemFn,

src/parse/idle.rs

@@ -1,5 +1,5 @@
 use proc_macro2::TokenStream as TokenStream2;
-use syn::{parse, ItemFn};
+use syn::{parse, ForeignItemFn, ItemFn, Stmt};
 
 use crate::{
     ast::{Idle, IdleArgs},
@@ -29,6 +29,37 @@ impl Idle {
                         context,
                         name: item.sig.ident,
                         stmts: item.block.stmts,
+                        is_extern: false,
+                    });
+                }
+            }
+        }
+
+        Err(parse::Error::new(
+            item.sig.ident.span(),
+            &format!(
+                "this `#[idle]` function must have signature `fn({}::Context) -> !`",
+                name
+            ),
+        ))
+    }
+    pub(crate) fn parse_foreign(args: IdleArgs, item: ForeignItemFn) -> parse::Result<Self> {
+        let valid_signature = util::check_foreign_fn_signature(&item)
+            && item.sig.inputs.len() == 1
+            && util::type_is_bottom(&item.sig.output);
+
+        let name = item.sig.ident.to_string();
+
+        if valid_signature {
+            if let Some((context, Ok(rest))) = util::parse_inputs(item.sig.inputs, &name) {
+                if rest.is_empty() {
+                    return Ok(Idle {
+                        args,
+                        attrs: item.attrs,
+                        context,
+                        name: item.sig.ident,
+                        stmts: Vec::<Stmt>::new(),
+                        is_extern: true,
                     });
                 }
             }

src/parse/init.rs

@@ -1,6 +1,6 @@
 use proc_macro2::TokenStream as TokenStream2;
 
-use syn::{parse, ItemFn};
+use syn::{parse, ForeignItemFn, ItemFn, Stmt};
 
 use crate::{
     ast::{Init, InitArgs},
@@ -35,6 +35,43 @@ impl Init {
                             stmts: item.block.stmts,
                             user_shared_struct,
                             user_local_struct,
+                            is_extern: false,
+                        });
+                    }
+                }
+            }
+        }
+
+        Err(parse::Error::new(
+            span,
+            &format!(
+                "the `#[init]` function must have signature `fn({}::Context) -> (Shared resources struct, Local resources struct, {0}::Monotonics)`",
+                name
+            ),
+        ))
+    }
+    pub(crate) fn parse_foreign(args: InitArgs, item: ForeignItemFn) -> parse::Result<Self> {
+        let valid_signature = util::check_foreign_fn_signature(&item) && item.sig.inputs.len() == 1;
+
+        let span = item.sig.ident.span();
+
+        let name = item.sig.ident.to_string();
+
+        if valid_signature {
+            if let Ok((user_shared_struct, user_local_struct)) =
+                util::type_is_init_return(&item.sig.output, &name)
+            {
+                if let Some((context, Ok(rest))) = util::parse_inputs(item.sig.inputs, &name) {
+                    if rest.is_empty() {
+                        return Ok(Init {
+                            args,
+                            attrs: item.attrs,
+                            context,
+                            name: item.sig.ident,
+                            stmts: Vec::<Stmt>::new(),
+                            user_shared_struct,
+                            user_local_struct,
+                            is_extern: true,
                         });
                     }
                 }