+++ /dev/null
-//! This module provides a simplified abstraction for working with
-//! code blocks identified by their integer `NodeId`. In particular,
-//! it captures a common set of attributes that all "function-like
-//! things" (represented by `FnLike` instances) share. For example,
-//! all `FnLike` instances have a type signature (be it explicit or
-//! inferred). And all `FnLike` instances have a body, i.e., the code
-//! that is run when the function-like thing it represents is invoked.
-//!
-//! With the above abstraction in place, one can treat the program
-//! text as a collection of blocks of code (and most such blocks are
-//! nested within a uniquely determined `FnLike`), and users can ask
-//! for the `Code` associated with a particular NodeId.
-
-use crate::hir::map::Map;
-use rustc_hir as hir;
-use rustc_hir::intravisit::FnKind;
-use rustc_hir::{Expr, FnDecl, Node};
-use rustc_span::symbol::Ident;
-use rustc_span::Span;
-
-/// An FnLikeNode is a Node that is like a fn, in that it has a decl
-/// and a body (as well as a NodeId, a span, etc).
-///
-/// More specifically, it is one of either:
-///
-/// - A function item,
-/// - A closure expr (i.e., an ExprKind::Closure), or
-/// - The default implementation for a trait method.
-///
-/// To construct one, use the `Code::from_node` function.
-#[derive(Copy, Clone, Debug)]
-pub struct FnLikeNode<'a> {
- node: Node<'a>,
-}
-
-/// MaybeFnLike wraps a method that indicates if an object
-/// corresponds to some FnLikeNode.
-trait MaybeFnLike {
- fn is_fn_like(&self) -> bool;
-}
-
-impl MaybeFnLike for hir::Item<'_> {
- fn is_fn_like(&self) -> bool {
- matches!(self.kind, hir::ItemKind::Fn(..))
- }
-}
-
-impl MaybeFnLike for hir::ImplItem<'_> {
- fn is_fn_like(&self) -> bool {
- matches!(self.kind, hir::ImplItemKind::Fn(..))
- }
-}
-
-impl MaybeFnLike for hir::TraitItem<'_> {
- fn is_fn_like(&self) -> bool {
- matches!(self.kind, hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)))
- }
-}
-
-impl MaybeFnLike for hir::Expr<'_> {
- fn is_fn_like(&self) -> bool {
- matches!(self.kind, hir::ExprKind::Closure(..))
- }
-}
-
-/// Carries either an FnLikeNode or an Expr, as these are the two
-/// constructs that correspond to "code" (as in, something from which
-/// we can construct a control-flow graph).
-#[derive(Copy, Clone)]
-pub enum Code<'a> {
- FnLike(FnLikeNode<'a>),
- Expr(&'a Expr<'a>),
-}
-
-impl<'a> Code<'a> {
- pub fn id(&self) -> hir::HirId {
- match *self {
- Code::FnLike(node) => node.id(),
- Code::Expr(block) => block.hir_id,
- }
- }
-
- /// Attempts to construct a Code from presumed FnLike or Expr node input.
- pub fn from_node(map: &Map<'a>, id: hir::HirId) -> Option<Code<'a>> {
- match map.get(id) {
- Node::Block(_) => {
- // Use the parent, hopefully an expression node.
- Code::from_node(map, map.get_parent_node(id))
- }
- Node::Expr(expr) => Some(Code::Expr(expr)),
- node => FnLikeNode::from_node(node).map(Code::FnLike),
- }
- }
-}
-
-/// These are all the components one can extract from a fn item for
-/// use when implementing FnLikeNode operations.
-struct ItemFnParts<'a> {
- ident: Ident,
- decl: &'a hir::FnDecl<'a>,
- header: hir::FnHeader,
- vis: &'a hir::Visibility<'a>,
- generics: &'a hir::Generics<'a>,
- body: hir::BodyId,
- id: hir::HirId,
- span: Span,
-}
-
-/// These are all the components one can extract from a closure expr
-/// for use when implementing FnLikeNode operations.
-struct ClosureParts<'a> {
- decl: &'a FnDecl<'a>,
- body: hir::BodyId,
- id: hir::HirId,
- span: Span,
-}
-
-impl<'a> ClosureParts<'a> {
- fn new(d: &'a FnDecl<'a>, b: hir::BodyId, id: hir::HirId, s: Span) -> Self {
- ClosureParts { decl: d, body: b, id, span: s }
- }
-}
-
-impl<'a> FnLikeNode<'a> {
- /// Attempts to construct a FnLikeNode from presumed FnLike node input.
- pub fn from_node(node: Node<'_>) -> Option<FnLikeNode<'_>> {
- let fn_like = match node {
- Node::Item(item) => item.is_fn_like(),
- Node::TraitItem(tm) => tm.is_fn_like(),
- Node::ImplItem(it) => it.is_fn_like(),
- Node::Expr(e) => e.is_fn_like(),
- _ => false,
- };
- fn_like.then_some(FnLikeNode { node })
- }
-
- pub fn body(self) -> hir::BodyId {
- self.handle(
- |i: ItemFnParts<'a>| i.body,
- |_, _, _: &'a hir::FnSig<'a>, _, body: hir::BodyId, _| body,
- |c: ClosureParts<'a>| c.body,
- )
- }
-
- pub fn decl(self) -> &'a FnDecl<'a> {
- self.handle(
- |i: ItemFnParts<'a>| &*i.decl,
- |_, _, sig: &'a hir::FnSig<'a>, _, _, _| &sig.decl,
- |c: ClosureParts<'a>| c.decl,
- )
- }
-
- pub fn span(self) -> Span {
- self.handle(
- |i: ItemFnParts<'_>| i.span,
- |_, _, _: &'a hir::FnSig<'a>, _, _, span| span,
- |c: ClosureParts<'_>| c.span,
- )
- }
-
- pub fn id(self) -> hir::HirId {
- self.handle(
- |i: ItemFnParts<'_>| i.id,
- |id, _, _: &'a hir::FnSig<'a>, _, _, _| id,
- |c: ClosureParts<'_>| c.id,
- )
- }
-
- pub fn constness(self) -> hir::Constness {
- self.kind().header().map_or(hir::Constness::NotConst, |header| header.constness)
- }
-
- pub fn asyncness(self) -> hir::IsAsync {
- self.kind().header().map_or(hir::IsAsync::NotAsync, |header| header.asyncness)
- }
-
- pub fn unsafety(self) -> hir::Unsafety {
- self.kind().header().map_or(hir::Unsafety::Normal, |header| header.unsafety)
- }
-
- pub fn kind(self) -> FnKind<'a> {
- let item = |p: ItemFnParts<'a>| -> FnKind<'a> {
- FnKind::ItemFn(p.ident, p.generics, p.header, p.vis)
- };
- let closure = |_: ClosureParts<'a>| FnKind::Closure;
- let method =
- |_, ident: Ident, sig: &'a hir::FnSig<'a>, vis, _, _| FnKind::Method(ident, sig, vis);
- self.handle(item, method, closure)
- }
-
- fn handle<A, I, M, C>(self, item_fn: I, method: M, closure: C) -> A
- where
- I: FnOnce(ItemFnParts<'a>) -> A,
- M: FnOnce(
- hir::HirId,
- Ident,
- &'a hir::FnSig<'a>,
- Option<&'a hir::Visibility<'a>>,
- hir::BodyId,
- Span,
- ) -> A,
- C: FnOnce(ClosureParts<'a>) -> A,
- {
- match self.node {
- Node::Item(i) => match i.kind {
- hir::ItemKind::Fn(ref sig, ref generics, block) => item_fn(ItemFnParts {
- id: i.hir_id(),
- ident: i.ident,
- decl: &sig.decl,
- body: block,
- vis: &i.vis,
- span: i.span,
- header: sig.header,
- generics,
- }),
- _ => bug!("item FnLikeNode that is not fn-like"),
- },
- Node::TraitItem(ti) => match ti.kind {
- hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
- method(ti.hir_id(), ti.ident, sig, None, body, ti.span)
- }
- _ => bug!("trait method FnLikeNode that is not fn-like"),
- },
- Node::ImplItem(ii) => match ii.kind {
- hir::ImplItemKind::Fn(ref sig, body) => {
- method(ii.hir_id(), ii.ident, sig, Some(&ii.vis), body, ii.span)
- }
- _ => bug!("impl method FnLikeNode that is not fn-like"),
- },
- Node::Expr(e) => match e.kind {
- hir::ExprKind::Closure(_, ref decl, block, _fn_decl_span, _gen) => {
- closure(ClosureParts::new(&decl, block, e.hir_id, e.span))
- }
- _ => bug!("expr FnLikeNode that is not fn-like"),
- },
- _ => bug!("other FnLikeNode that is not fn-like"),
- }
- }
-}
projects / rustc.git / blobdiff