Data structure to represent possibly unsafe module

Author: dtolnay

macro/src/expand.rs

@@ -1,21 +1,20 @@
 use crate::syntax::atom::Atom::{self, *};
+use crate::syntax::file::Module;
 use crate::syntax::namespace::Namespace;
 use crate::syntax::report::Errors;
 use crate::syntax::symbol::Symbol;
 use crate::syntax::{
     self, check, mangle, Api, Enum, ExternFn, ExternType, Signature, Struct, Type, TypeAlias, Types,
 };
-use proc_macro2::{Ident, Span, TokenStream};
+use proc_macro2::{Ident, TokenStream};
 use quote::{format_ident, quote, quote_spanned, ToTokens};
-use syn::{parse_quote, Error, ItemMod, Result, Token};
+use std::mem;
+use syn::{parse_quote, Result, Token};
 
-pub fn bridge(namespace: &Namespace, mut ffi: ItemMod) -> Result<TokenStream> {
+pub fn bridge(namespace: &Namespace, mut ffi: Module) -> Result<TokenStream> {
     let ref mut errors = Errors::new();
-    let content = ffi.content.take().ok_or(Error::new(
-        Span::call_site(),
-        "#[cxx::bridge] module must have inline contents",
-    ))?;
-    let ref apis = syntax::parse_items(errors, content.1);
+    let content = mem::take(&mut ffi.content);
+    let ref apis = syntax::parse_items(errors, content);
     let ref types = Types::collect(errors, apis);
     errors.propagate()?;
     check::typecheck(errors, namespace, apis, types);
@@ -24,7 +23,7 @@ pub fn bridge(namespace: &Namespace, mut ffi: ItemMod) -> Result<TokenStream> {
     Ok(expand(namespace, ffi, apis, types))
 }
 
-fn expand(namespace: &Namespace, ffi: ItemMod, apis: &[Api], types: &Types) -> TokenStream {
+fn expand(namespace: &Namespace, ffi: Module, apis: &[Api], types: &Types) -> TokenStream {
     let mut expanded = TokenStream::new();
     let mut hidden = TokenStream::new();
 

macro/src/lib.rs

@@ -13,9 +13,10 @@ mod expand;
 mod syntax;
 mod type_id;
 
+use crate::syntax::file::Module;
 use crate::syntax::namespace::Namespace;
 use proc_macro::TokenStream;
-use syn::{parse_macro_input, ItemMod, LitStr};
+use syn::{parse_macro_input, LitStr};
 
 /// `#[cxx::bridge] mod ffi { ... }`
 ///
@@ -39,7 +40,7 @@ pub fn bridge(args: TokenStream, input: TokenStream) -> TokenStream {
     let _ = syntax::error::ERRORS;
 
     let namespace = parse_macro_input!(args as Namespace);
-    let ffi = parse_macro_input!(input as ItemMod);
+    let ffi = parse_macro_input!(input as Module);
 
     expand::bridge(&namespace, ffi)
         .unwrap_or_else(|err| err.to_compile_error())

syntax/file.rs

@@ -0,0 +1,47 @@
+use proc_macro2::Span;
+use syn::parse::{Error, Parse, ParseStream, Result};
+use syn::{braced, token, Attribute, Ident, Item, Token, Visibility};
+
+pub struct Module {
+    pub attrs: Vec<Attribute>,
+    pub vis: Visibility,
+    // TODO: unsafety
+    pub mod_token: Token![mod],
+    pub ident: Ident,
+    pub brace_token: token::Brace,
+    pub content: Vec<Item>,
+}
+
+impl Parse for Module {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let mut attrs = input.call(Attribute::parse_outer)?;
+        let vis: Visibility = input.parse()?;
+        let mod_token: Token![mod] = input.parse()?;
+        let ident: Ident = input.parse()?;
+
+        if input.peek(Token![;]) {
+            return Err(Error::new(
+                Span::call_site(),
+                "#[cxx::bridge] module must have inline contents",
+            ))?;
+        }
+
+        let content;
+        let brace_token = braced!(content in input);
+        attrs.extend(content.call(Attribute::parse_inner)?);
+
+        let mut items = Vec::new();
+        while !content.is_empty() {
+            items.push(content.parse()?);
+        }
+
+        Ok(Module {
+            attrs,
+            vis,
+            mod_token,
+            ident,
+            brace_token,
+            content: items,
+        })
+    }
+}

syntax/mod.rs

@@ -7,6 +7,7 @@ mod derive;
 mod discriminant;
 mod doc;
 pub mod error;
+pub mod file;
 pub mod ident;
 mod impls;
 pub mod mangle;