Generalize and abstract ThinAttributes

src/librustc/hir/fold.rs

@@ -14,7 +14,6 @@
 use hir::*;
 use syntax::ast::{Name, NodeId, DUMMY_NODE_ID, Attribute, Attribute_, MetaItem};
 use syntax::ast::MetaItemKind;
-use syntax::attr::ThinAttributesExt;
 use hir;
 use syntax::codemap::{respan, Span, Spanned};
 use syntax::ptr::P;
@@ -292,8 +291,11 @@ pub fn noop_fold_view_path<T: Folder>(view_path: P<ViewPath>, fld: &mut T) -> P<
     })
 }
 
-pub fn fold_attrs<T: Folder>(attrs: HirVec<Attribute>, fld: &mut T) -> HirVec<Attribute> {
-    attrs.move_flat_map(|x| fld.fold_attribute(x))
+pub fn fold_attrs<T, F>(attrs: T, fld: &mut F) -> T
+    where T: Into<Vec<Attribute>> + From<Vec<Attribute>>,
+          F: Folder,
+{
+    attrs.into().move_flat_map(|x| fld.fold_attribute(x)).into()
 }
 
 pub fn noop_fold_arm<T: Folder>(Arm { attrs, pats, guard, body }: Arm, fld: &mut T) -> Arm {
@@ -461,7 +463,7 @@ pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
             pat: fld.fold_pat(pat),
             init: init.map(|e| fld.fold_expr(e)),
             span: fld.new_span(span),
-            attrs: attrs.map_thin_attrs(|attrs| fold_attrs(attrs.into(), fld).into()),
+            attrs: fold_attrs(attrs, fld),
         }
     })
 }
@@ -1078,7 +1080,7 @@ pub fn noop_fold_expr<T: Folder>(Expr { id, node, span, attrs }: Expr, folder: &
             }
         },
         span: folder.new_span(span),
-        attrs: attrs.map_thin_attrs(|attrs| fold_attrs(attrs.into(), folder).into()),
+        attrs: fold_attrs(attrs, folder),
     }
 }
 

src/librustc/hir/intravisit.rs

@@ -27,7 +27,6 @@
 
 use syntax::abi::Abi;
 use syntax::ast::{NodeId, CRATE_NODE_ID, Name, Attribute};
-use syntax::attr::ThinAttributesExt;
 use syntax::codemap::{Span, Spanned};
 use hir::*;
 
@@ -756,7 +755,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
             walk_list!(visitor, visit_arm, arms);
         }
         ExprClosure(_, ref function_declaration, ref body, _fn_decl_span) => {
-            visitor.visit_fn(FnKind::Closure(expression.attrs.as_attr_slice()),
+            visitor.visit_fn(FnKind::Closure(&expression.attrs),
                              function_declaration,
                              body,
                              expression.span,

src/librustc/hir/map/blocks.rs

@@ -27,7 +27,6 @@ use hir::map::{self, Node};
 use syntax::abi;
 use hir::{Block, FnDecl};
 use syntax::ast::{Attribute, Name, NodeId};
-use syntax::attr::ThinAttributesExt;
 use hir as ast;
 use syntax::codemap::Span;
 use hir::intravisit::FnKind;
@@ -257,11 +256,7 @@ impl<'a> FnLikeNode<'a> {
             }
             map::NodeExpr(e) => match e.node {
                 ast::ExprClosure(_, ref decl, ref block, _fn_decl_span) =>
-                    closure(ClosureParts::new(&decl,
-                                              &block,
-                                              e.id,
-                                              e.span,
-                                              e.attrs.as_attr_slice())),
+                    closure(ClosureParts::new(&decl, &block, e.id, e.span, &e.attrs)),
                 _ => bug!("expr FnLikeNode that is not fn-like"),
             },
             _ => bug!("other FnLikeNode that is not fn-like"),

src/librustc/hir/map/mod.rs

@@ -23,7 +23,6 @@ use hir::def_id::{CRATE_DEF_INDEX, DefId, DefIndex};
 
 use syntax::abi::Abi;
 use syntax::ast::{self, Name, NodeId, DUMMY_NODE_ID, };
-use syntax::attr::ThinAttributesExt;
 use syntax::codemap::{Span, Spanned};
 use syntax::visit;
 
@@ -577,7 +576,7 @@ impl<'ast> Map<'ast> {
             Some(NodeTraitItem(ref ti)) => Some(&ti.attrs[..]),
             Some(NodeImplItem(ref ii)) => Some(&ii.attrs[..]),
             Some(NodeVariant(ref v)) => Some(&v.node.attrs[..]),
-            Some(NodeExpr(ref e)) => Some(e.attrs.as_attr_slice()),
+            Some(NodeExpr(ref e)) => Some(&*e.attrs),
             Some(NodeStmt(ref s)) => Some(s.node.attrs()),
             // unit/tuple structs take the attributes straight from
             // the struct definition.

src/librustc/hir/mod.rs

@@ -40,9 +40,9 @@ use syntax::codemap::{self, mk_sp, respan, Span, Spanned, ExpnId};
 use syntax::abi::Abi;
 use syntax::ast::{Name, NodeId, DUMMY_NODE_ID, TokenTree, AsmDialect};
 use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy, MetaItem};
-use syntax::attr::{ThinAttributes, ThinAttributesExt};
 use syntax::parse::token::{keywords, InternedString};
 use syntax::ptr::P;
+use syntax::util::ThinVec;
 
 use std::collections::BTreeMap;
 use std::fmt;
@@ -732,7 +732,7 @@ impl Stmt_ {
         match *self {
             StmtDecl(ref d, _) => d.node.attrs(),
             StmtExpr(ref e, _) |
-            StmtSemi(ref e, _) => e.attrs.as_attr_slice(),
+            StmtSemi(ref e, _) => &e.attrs,
         }
     }
 
@@ -756,7 +756,7 @@ pub struct Local {
     pub init: Option<P<Expr>>,
     pub id: NodeId,
     pub span: Span,
-    pub attrs: ThinAttributes,
+    pub attrs: ThinVec<Attribute>,
 }
 
 pub type Decl = Spanned<Decl_>;
@@ -772,7 +772,7 @@ pub enum Decl_ {
 impl Decl_ {
     pub fn attrs(&self) -> &[Attribute] {
         match *self {
-            DeclLocal(ref l) => l.attrs.as_attr_slice(),
+            DeclLocal(ref l) => &l.attrs,
             DeclItem(_) => &[]
         }
     }
@@ -817,7 +817,7 @@ pub struct Expr {
     pub id: NodeId,
     pub node: Expr_,
     pub span: Span,
-    pub attrs: ThinAttributes,
+    pub attrs: ThinVec<Attribute>,
 }
 
 impl fmt::Debug for Expr {

src/librustc/lint/context.rs

@@ -44,7 +44,6 @@ use syntax::codemap::Span;
 use syntax::errors::DiagnosticBuilder;
 use syntax::parse::token::InternedString;
 use syntax::ast;
-use syntax::attr::ThinAttributesExt;
 use hir;
 use hir::intravisit as hir_visit;
 use hir::intravisit::{IdVisitor, IdVisitingOperation};
@@ -767,7 +766,7 @@ impl<'a, 'tcx, 'v> hir_visit::Visitor<'v> for LateContext<'a, 'tcx> {
     }
 
     fn visit_expr(&mut self, e: &hir::Expr) {
-        self.with_lint_attrs(e.attrs.as_attr_slice(), |cx| {
+        self.with_lint_attrs(&e.attrs, |cx| {
             run_lints!(cx, check_expr, late_passes, e);
             hir_visit::walk_expr(cx, e);
         })
@@ -832,7 +831,7 @@ impl<'a, 'tcx, 'v> hir_visit::Visitor<'v> for LateContext<'a, 'tcx> {
     }
 
     fn visit_local(&mut self, l: &hir::Local) {
-        self.with_lint_attrs(l.attrs.as_attr_slice(), |cx| {
+        self.with_lint_attrs(&l.attrs, |cx| {
             run_lints!(cx, check_local, late_passes, l);
             hir_visit::walk_local(cx, l);
         })
@@ -928,7 +927,7 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
     }
 
     fn visit_expr(&mut self, e: &ast::Expr) {
-        self.with_lint_attrs(e.attrs.as_attr_slice(), |cx| {
+        self.with_lint_attrs(&e.attrs, |cx| {
             run_lints!(cx, check_expr, early_passes, e);
             ast_visit::walk_expr(cx, e);
         })
@@ -988,7 +987,7 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
     }
 
     fn visit_local(&mut self, l: &ast::Local) {
-        self.with_lint_attrs(l.attrs.as_attr_slice(), |cx| {
+        self.with_lint_attrs(&l.attrs, |cx| {
             run_lints!(cx, check_local, early_passes, l);
             ast_visit::walk_local(cx, l);
         })

src/librustc_const_eval/check_match.rs

@@ -451,7 +451,7 @@ fn const_val_to_expr(value: &ConstVal) -> P<hir::Expr> {
         id: 0,
         node: hir::ExprLit(P(Spanned { node: node, span: DUMMY_SP })),
         span: DUMMY_SP,
-        attrs: None,
+        attrs: ast::ThinVec::new(),
     })
 }
 

src/librustc_driver/pretty.rs

@@ -672,7 +672,7 @@ impl fold::Folder for ReplaceBodyWithLoop {
                 node: ast::ExprKind::Loop(empty_block, None),
                 id: ast::DUMMY_NODE_ID,
                 span: codemap::DUMMY_SP,
-                attrs: None,
+                attrs: ast::ThinVec::new(),
             });
 
             expr_to_block(b.rules, Some(loop_expr))

src/libsyntax/ast.rs

@@ -14,8 +14,9 @@ pub use self::TyParamBound::*;
 pub use self::UnsafeSource::*;
 pub use self::ViewPath_::*;
 pub use self::PathParameters::*;
+pub use util::ThinVec;
 
-use attr::{ThinAttributes, HasAttrs};
+use attr::HasAttrs;
 use codemap::{mk_sp, respan, Span, Spanned, DUMMY_SP, ExpnId};
 use abi::Abi;
 use errors;
@@ -809,7 +810,7 @@ pub enum StmtKind {
     /// Expr with trailing semi-colon (may have any type):
     Semi(P<Expr>, NodeId),
 
-    Mac(P<Mac>, MacStmtStyle, ThinAttributes),
+    Mac(P<Mac>, MacStmtStyle, ThinVec<Attribute>),
 }
 
 impl StmtKind {
@@ -851,7 +852,7 @@ pub struct Local {
     pub init: Option<P<Expr>>,
     pub id: NodeId,
     pub span: Span,
-    pub attrs: ThinAttributes,
+    pub attrs: ThinVec<Attribute>,
 }
 
 impl Local {
@@ -912,7 +913,7 @@ pub struct Expr {
     pub id: NodeId,
     pub node: ExprKind,
     pub span: Span,
-    pub attrs: ThinAttributes
+    pub attrs: ThinVec<Attribute>
 }
 
 impl Expr {

src/libsyntax/attr.rs

@@ -26,6 +26,7 @@ use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
 use parse::token::InternedString;
 use parse::{ParseSess, token};
 use ptr::P;
+use util::ThinVec;
 
 use std::cell::{RefCell, Cell};
 use std::collections::HashSet;
@@ -803,80 +804,6 @@ impl IntType {
     }
 }
 
-/// A list of attributes, behind a optional box as
-/// a space optimization.
-pub type ThinAttributes = Option<Box<Vec<Attribute>>>;
-
-pub trait ThinAttributesExt {
-    fn map_thin_attrs<F>(self, f: F) -> Self
-        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute>;
-    fn prepend(mut self, attrs: Self) -> Self;
-    fn append(mut self, attrs: Self) -> Self;
-    fn update<F>(&mut self, f: F)
-        where Self: Sized,
-              F: FnOnce(Self) -> Self;
-    fn as_attr_slice(&self) -> &[Attribute];
-    fn into_attr_vec(self) -> Vec<Attribute>;
-}
-
-impl ThinAttributesExt for ThinAttributes {
-    fn map_thin_attrs<F>(self, f: F) -> Self
-        where F: FnOnce(Vec<Attribute>) -> Vec<Attribute>
-    {
-        f(self.map(|b| *b).unwrap_or(Vec::new())).into_thin_attrs()
-    }
-
-    fn prepend(self, attrs: ThinAttributes) -> Self {
-        attrs.map_thin_attrs(|mut attrs| {
-            attrs.extend(self.into_attr_vec());
-            attrs
-        })
-    }
-
-    fn append(self, attrs: ThinAttributes) -> Self {
-        self.map_thin_attrs(|mut self_| {
-            self_.extend(attrs.into_attr_vec());
-            self_
-        })
-    }
-
-    fn update<F>(&mut self, f: F)
-        where Self: Sized,
-              F: FnOnce(ThinAttributes) -> ThinAttributes
-    {
-        let self_ = f(self.take());
-        *self = self_;
-    }
-
-    fn as_attr_slice(&self) -> &[Attribute] {
-        match *self {
-            Some(ref b) => b,
-            None => &[],
-        }
-    }
-
-    fn into_attr_vec(self) -> Vec<Attribute> {
-        match self {
-            Some(b) => *b,
-            None => Vec::new(),
-        }
-    }
-}
-
-pub trait AttributesExt {
-    fn into_thin_attrs(self) -> ThinAttributes;
-}
-
-impl AttributesExt for Vec<Attribute> {
-    fn into_thin_attrs(self) -> ThinAttributes {
-        if self.len() == 0 {
-            None
-        } else {
-            Some(Box::new(self))
-        }
-    }
-}
-
 pub trait HasAttrs: Sized {
     fn attrs(&self) -> &[ast::Attribute];
     fn map_attrs<F: FnOnce(Vec<ast::Attribute>) -> Vec<ast::Attribute>>(self, f: F) -> Self;
@@ -885,13 +812,13 @@ pub trait HasAttrs: Sized {
 /// A cheap way to add Attributes to an AST node.
 pub trait WithAttrs {
     // FIXME: Could be extended to anything IntoIter<Item=Attribute>
-    fn with_attrs(self, attrs: ThinAttributes) -> Self;
+    fn with_attrs(self, attrs: ThinVec<Attribute>) -> Self;
 }
 
 impl<T: HasAttrs> WithAttrs for T {
-    fn with_attrs(self, attrs: ThinAttributes) -> Self {
+    fn with_attrs(self, attrs: ThinVec<Attribute>) -> Self {
         self.map_attrs(|mut orig_attrs| {
-            orig_attrs.extend(attrs.into_attr_vec());
+            orig_attrs.extend::<Vec<_>>(attrs.into());
             orig_attrs
         })
     }
@@ -906,12 +833,12 @@ impl HasAttrs for Vec<Attribute> {
     }
 }
 
-impl HasAttrs for ThinAttributes {
+impl HasAttrs for ThinVec<Attribute> {
     fn attrs(&self) -> &[Attribute] {
-        self.as_attr_slice()
+        &self
     }
     fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
-        self.map_thin_attrs(f)
+        f(self.into()).into()
     }
 }
 

src/libsyntax/ext/base.rs

@@ -350,7 +350,7 @@ impl DummyResult {
             id: ast::DUMMY_NODE_ID,
             node: ast::ExprKind::Lit(P(codemap::respan(sp, ast::LitKind::Bool(false)))),
             span: sp,
-            attrs: None,
+            attrs: ast::ThinVec::new(),
         })
     }
 

src/libsyntax/ext/build.rs

@@ -525,7 +525,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             init: Some(ex),
             id: ast::DUMMY_NODE_ID,
             span: sp,
-            attrs: None,
+            attrs: ast::ThinVec::new(),
         });
         let decl = respan(sp, ast::DeclKind::Local(local));
         respan(sp, ast::StmtKind::Decl(P(decl), ast::DUMMY_NODE_ID))
@@ -550,7 +550,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             init: Some(ex),
             id: ast::DUMMY_NODE_ID,
             span: sp,
-            attrs: None,
+            attrs: ast::ThinVec::new(),
         });
         let decl = respan(sp, ast::DeclKind::Local(local));
         P(respan(sp, ast::StmtKind::Decl(P(decl), ast::DUMMY_NODE_ID)))
@@ -587,7 +587,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             id: ast::DUMMY_NODE_ID,
             node: node,
             span: span,
-            attrs: None,
+            attrs: ast::ThinVec::new(),
         })
     }