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use crate::clean::{self, PrimitiveType};
use crate::html::sources;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::DefId;
use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::{ExprKind, HirId, Mod, Node};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::TyCtxt;
use rustc_span::hygiene::MacroKind;
use rustc_span::{BytePos, ExpnKind, Span};
use std::path::{Path, PathBuf};
/// This enum allows us to store two different kinds of information:
///
/// In case the `span` definition comes from the same crate, we can simply get the `span` and use
/// it as is.
///
/// Otherwise, we store the definition `DefId` and will generate a link to the documentation page
/// instead of the source code directly.
#[derive(Debug)]
pub(crate) enum LinkFromSrc {
Local(clean::Span),
External(DefId),
Primitive(PrimitiveType),
}
/// This function will do at most two things:
///
/// 1. Generate a `span` correspondence map which links an item `span` to its definition `span`.
/// 2. Collect the source code files.
///
/// It returns the `krate`, the source code files and the `span` correspondence map.
///
/// Note about the `span` correspondence map: the keys are actually `(lo, hi)` of `span`s. We don't
/// need the `span` context later on, only their position, so instead of keep a whole `Span`, we
/// only keep the `lo` and `hi`.
pub(crate) fn collect_spans_and_sources(
tcx: TyCtxt<'_>,
krate: &clean::Crate,
src_root: &Path,
include_sources: bool,
generate_link_to_definition: bool,
) -> (FxHashMap<PathBuf, String>, FxHashMap<Span, LinkFromSrc>) {
let mut visitor = SpanMapVisitor { tcx, matches: FxHashMap::default() };
if include_sources {
if generate_link_to_definition {
tcx.hir().walk_toplevel_module(&mut visitor);
}
let sources = sources::collect_local_sources(tcx, src_root, krate);
(sources, visitor.matches)
} else {
(Default::default(), Default::default())
}
}
struct SpanMapVisitor<'tcx> {
pub(crate) tcx: TyCtxt<'tcx>,
pub(crate) matches: FxHashMap<Span, LinkFromSrc>,
}
impl<'tcx> SpanMapVisitor<'tcx> {
/// This function is where we handle `hir::Path` elements and add them into the "span map".
fn handle_path(&mut self, path: &rustc_hir::Path<'_>) {
let info = match path.res {
// FIXME: For now, we handle `DefKind` if it's not a `DefKind::TyParam`.
// Would be nice to support them too alongside the other `DefKind`
// (such as primitive types!).
Res::Def(kind, def_id) if kind != DefKind::TyParam => Some(def_id),
Res::Local(_) => None,
Res::PrimTy(p) => {
// FIXME: Doesn't handle "path-like" primitives like arrays or tuples.
self.matches.insert(path.span, LinkFromSrc::Primitive(PrimitiveType::from(p)));
return;
}
Res::Err => return,
_ => return,
};
if let Some(span) = self.tcx.hir().res_span(path.res) {
self.matches.insert(path.span, LinkFromSrc::Local(clean::Span::new(span)));
} else if let Some(def_id) = info {
self.matches.insert(path.span, LinkFromSrc::External(def_id));
}
}
/// Adds the macro call into the span map. Returns `true` if the `span` was inside a macro
/// expansion, whether or not it was added to the span map.
///
/// The idea for the macro support is to check if the current `Span` comes from expansion. If
/// so, we loop until we find the macro definition by using `outer_expn_data` in a loop.
/// Finally, we get the information about the macro itself (`span` if "local", `DefId`
/// otherwise) and store it inside the span map.
fn handle_macro(&mut self, span: Span) -> bool {
if !span.from_expansion() {
return false;
}
// So if the `span` comes from a macro expansion, we need to get the original
// macro's `DefId`.
let mut data = span.ctxt().outer_expn_data();
let mut call_site = data.call_site;
// Macros can expand to code containing macros, which will in turn be expanded, etc.
// So the idea here is to "go up" until we're back to code that was generated from
// macro expansion so that we can get the `DefId` of the original macro that was at the
// origin of this expansion.
while call_site.from_expansion() {
data = call_site.ctxt().outer_expn_data();
call_site = data.call_site;
}
let macro_name = match data.kind {
ExpnKind::Macro(MacroKind::Bang, macro_name) => macro_name,
// Even though we don't handle this kind of macro, this `data` still comes from
// expansion so we return `true` so we don't go any deeper in this code.
_ => return true,
};
let link_from_src = match data.macro_def_id {
Some(macro_def_id) if macro_def_id.is_local() => {
LinkFromSrc::Local(clean::Span::new(data.def_site))
}
Some(macro_def_id) => LinkFromSrc::External(macro_def_id),
None => return true,
};
let new_span = data.call_site;
let macro_name = macro_name.as_str();
// The "call_site" includes the whole macro with its "arguments". We only want
// the macro name.
let new_span = new_span.with_hi(new_span.lo() + BytePos(macro_name.len() as u32));
self.matches.insert(new_span, link_from_src);
true
}
}
impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
type NestedFilter = nested_filter::All;
fn nested_visit_map(&mut self) -> Self::Map {
self.tcx.hir()
}
fn visit_path(&mut self, path: &rustc_hir::Path<'tcx>, _id: HirId) {
if self.handle_macro(path.span) {
return;
}
self.handle_path(path);
intravisit::walk_path(self, path);
}
fn visit_mod(&mut self, m: &'tcx Mod<'tcx>, span: Span, id: HirId) {
// To make the difference between "mod foo {}" and "mod foo;". In case we "import" another
// file, we want to link to it. Otherwise no need to create a link.
if !span.overlaps(m.spans.inner_span) {
// Now that we confirmed it's a file import, we want to get the span for the module
// name only and not all the "mod foo;".
if let Some(Node::Item(item)) = self.tcx.hir().find(id) {
self.matches.insert(
item.ident.span,
LinkFromSrc::Local(clean::Span::new(m.spans.inner_span)),
);
}
}
intravisit::walk_mod(self, m, id);
}
fn visit_expr(&mut self, expr: &'tcx rustc_hir::Expr<'tcx>) {
if let ExprKind::MethodCall(segment, ..) = expr.kind {
let hir = self.tcx.hir();
let body_id = hir.enclosing_body_owner(segment.hir_id);
// FIXME: this is showing error messages for parts of the code that are not
// compiled (because of cfg)!
//
// See discussion in https://github.com/rust-lang/rust/issues/69426#issuecomment-1019412352
let typeck_results = self
.tcx
.typeck_body(hir.maybe_body_owned_by(body_id).expect("a body which isn't a body"));
if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
self.matches.insert(
segment.ident.span,
match hir.span_if_local(def_id) {
Some(span) => LinkFromSrc::Local(clean::Span::new(span)),
None => LinkFromSrc::External(def_id),
},
);
}
} else if self.handle_macro(expr.span) {
// We don't want to go deeper into the macro.
return;
}
intravisit::walk_expr(self, expr);
}
}