Merge pull request #997 from dtolnay/cfg

Store parsed cfg attributes into syntax tree

gen/src/nested.rs

@@ -52,6 +52,7 @@ fn sort_by_inner_namespace(apis: Vec<&Api>, depth: usize) -> NamespaceEntries {
 mod tests {
     use super::NamespaceEntries;
     use crate::syntax::attrs::OtherAttrs;
+    use crate::syntax::cfg::CfgExpr;
     use crate::syntax::namespace::Namespace;
     use crate::syntax::{Api, Doc, ExternType, ForeignName, Lang, Lifetimes, Pair};
     use proc_macro2::{Ident, Span};
@@ -128,6 +129,7 @@ mod tests {
     fn make_api(ns: Option<&str>, ident: &str) -> Api {
         let ns = ns.map_or(Namespace::ROOT, |ns| syn::parse_str(ns).unwrap());
         Api::CxxType(ExternType {
+            cfg: CfgExpr::Unconditional,
             lang: Lang::Rust,
             doc: Doc::new(),
             derives: Vec::new(),

macro/src/expand.rs

@@ -1,5 +1,6 @@
 use crate::syntax::atom::Atom::*;
 use crate::syntax::attrs::{self, OtherAttrs};
+use crate::syntax::cfg::CfgExpr;
 use crate::syntax::file::Module;
 use crate::syntax::instantiate::{ImplKey, NamedImplKey};
 use crate::syntax::qualified::QualifiedName;
@@ -19,11 +20,13 @@ use syn::{parse_quote, punctuated, Generics, Lifetime, Result, Token};
 pub fn bridge(mut ffi: Module) -> Result<TokenStream> {
     let ref mut errors = Errors::new();
 
+    let mut cfg = CfgExpr::Unconditional;
     let mut doc = Doc::new();
     let attrs = attrs::parse(
         errors,
         mem::take(&mut ffi.attrs),
         attrs::Parser {
+            cfg: Some(&mut cfg),
             doc: Some(&mut doc),
             ..Default::default()
         },

syntax/attrs.rs

@@ -1,3 +1,4 @@
+use crate::syntax::cfg::CfgExpr;
 use crate::syntax::namespace::Namespace;
 use crate::syntax::report::Errors;
 use crate::syntax::Atom::{self, *};
@@ -27,6 +28,7 @@ use syn::{parenthesized, token, Attribute, Error, LitStr, Path, Result, Token};
 //
 #[derive(Default)]
 pub struct Parser<'a> {
+    pub cfg: Option<&'a mut CfgExpr>,
     pub doc: Option<&'a mut Doc>,
     pub derives: Option<&'a mut Vec<Derive>>,
     pub repr: Option<&'a mut Option<Atom>>,
@@ -128,11 +130,12 @@ pub fn parse(cx: &mut Errors, attrs: Vec<Attribute>, mut parser: Parser) -> Othe
         } else if attr.path.is_ident("cfg") {
             match cfg::parse_attribute.parse2(attr.tokens.clone()) {
                 Ok(cfg_expr) => {
-                    // TODO
-                    let _ = cfg_expr;
-                    cx.error(&attr, "support for cfg attribute is not implemented yet");
-                    passthrough_attrs.push(attr);
-                    continue;
+                    if let Some(cfg) = &mut parser.cfg {
+                        cfg.merge(cfg_expr);
+                        cx.error(&attr, "support for cfg attribute is not implemented yet");
+                        passthrough_attrs.push(attr);
+                        continue;
+                    }
                 }
                 Err(err) => {
                     cx.push(err);

syntax/cfg.rs

@@ -1,14 +1,30 @@
 use proc_macro2::Ident;
+use std::mem;
 use syn::parse::{Error, ParseStream, Result};
 use syn::{parenthesized, token, LitStr, Token};
 
+#[derive(Clone)]
 pub enum CfgExpr {
+    Unconditional,
     Eq(Ident, Option<String>),
     All(Vec<CfgExpr>),
     Any(Vec<CfgExpr>),
     Not(Box<CfgExpr>),
 }
 
+impl CfgExpr {
+    pub fn merge(&mut self, expr: CfgExpr) {
+        if let CfgExpr::Unconditional = self {
+            *self = expr;
+        } else if let CfgExpr::All(list) = self {
+            list.push(expr);
+        } else {
+            let prev = mem::replace(self, CfgExpr::Unconditional);
+            *self = CfgExpr::All(vec![prev, expr]);
+        }
+    }
+}
+
 pub fn parse_attribute(input: ParseStream) -> Result<CfgExpr> {
     let content;
     parenthesized!(content in input);

syntax/impls.rs

@@ -8,12 +8,14 @@ use std::ops::{Deref, DerefMut};
 impl PartialEq for Include {
     fn eq(&self, other: &Self) -> bool {
         let Include {
+            cfg: _,
             path,
             kind,
             begin_span: _,
             end_span: _,
         } = self;
         let Include {
+            cfg: _,
             path: path2,
             kind: kind2,
             begin_span: _,
@@ -335,6 +337,7 @@ impl PartialEq for Signature {
             && args.len() == args2.len()
             && args.iter().zip(args2).all(|(arg, arg2)| {
                 let Var {
+                    cfg: _,
                     doc: _,
                     attrs: _,
                     visibility: _,
@@ -343,6 +346,7 @@ impl PartialEq for Signature {
                     ty,
                 } = arg;
                 let Var {
+                    cfg: _,
                     doc: _,
                     attrs: _,
                     visibility: _,
@@ -372,6 +376,7 @@ impl Hash for Signature {
         receiver.hash(state);
         for arg in args {
             let Var {
+                cfg: _,
                 doc: _,
                 attrs: _,
                 visibility: _,

syntax/mod.rs

@@ -2,7 +2,7 @@
 
 pub mod atom;
 pub mod attrs;
-mod cfg;
+pub mod cfg;
 pub mod check;
 pub mod derive;
 mod discriminant;
@@ -31,6 +31,7 @@ pub mod types;
 mod visit;
 
 use self::attrs::OtherAttrs;
+use self::cfg::CfgExpr;
 use self::namespace::Namespace;
 use self::parse::kw;
 use self::symbol::Symbol;
@@ -60,6 +61,7 @@ pub enum Api {
 }
 
 pub struct Include {
+    pub cfg: CfgExpr,
     pub path: String,
     pub kind: IncludeKind,
     pub begin_span: Span,
@@ -76,6 +78,7 @@ pub enum IncludeKind {
 }
 
 pub struct ExternType {
+    pub cfg: CfgExpr,
     pub lang: Lang,
     pub doc: Doc,
     pub derives: Vec<Derive>,
@@ -91,6 +94,7 @@ pub struct ExternType {
 }
 
 pub struct Struct {
+    pub cfg: CfgExpr,
     pub doc: Doc,
     pub derives: Vec<Derive>,
     pub attrs: OtherAttrs,
@@ -103,6 +107,7 @@ pub struct Struct {
 }
 
 pub struct Enum {
+    pub cfg: CfgExpr,
     pub doc: Doc,
     pub derives: Vec<Derive>,
     pub attrs: OtherAttrs,
@@ -130,6 +135,7 @@ pub enum EnumRepr {
 }
 
 pub struct ExternFn {
+    pub cfg: CfgExpr,
     pub lang: Lang,
     pub doc: Doc,
     pub attrs: OtherAttrs,
@@ -141,6 +147,7 @@ pub struct ExternFn {
 }
 
 pub struct TypeAlias {
+    pub cfg: CfgExpr,
     pub doc: Doc,
     pub derives: Vec<Derive>,
     pub attrs: OtherAttrs,
@@ -183,6 +190,7 @@ pub struct Signature {
 }
 
 pub struct Var {
+    pub cfg: CfgExpr,
     pub doc: Doc,
     pub attrs: OtherAttrs,
     pub visibility: Token![pub],
@@ -205,6 +213,7 @@ pub struct Receiver {
 }
 
 pub struct Variant {
+    pub cfg: CfgExpr,
     pub doc: Doc,
     pub attrs: OtherAttrs,
     pub name: Pair,