Remove LightSpan and use Span directly

GuillaumeGomez · GuillaumeGomez · commit dfe4fec783c6 · 2021-08-05T23:08:29.000+02:00
diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
@@ -14,20 +14,16 @@ use std::iter::Peekable;
 use rustc_lexer::{LiteralKind, TokenKind};
 use rustc_span::edition::Edition;
 use rustc_span::symbol::Symbol;
+use rustc_span::{BytePos, Span, DUMMY_SP};
 
 use super::format::{self, Buffer};
-use super::render::{LightSpan, LinkFromSrc};
+use super::render::LinkFromSrc;
 
 /// This type is needed in case we want to render links on items to allow to go to their definition.
 crate struct ContextInfo<'a, 'b, 'c> {
     crate context: &'a Context<'b>,
-    /// This represents the "lo" bytes of the current file we're rendering. To get a [`Span`] from
-    /// it, you just need to add add your current byte position in the string and its length (to get
-    /// the "hi" part).
-    ///
-    /// This is used to create a [`LightSpan`] which is then used as an index in the `span_map` in
-    /// order to retrieve the definition's [`Span`] (which is used to generate the URL).
-    crate file_span_lo: u32,
+    /// This span contains the current file we're going through.
+    crate file_span: Span,
     /// This field is used to know "how far" from the top of the directory we are to link to either
     /// documentation pages or other source pages.
     crate root_path: &'c str,
@@ -86,7 +82,6 @@ fn write_header(out: &mut Buffer, class: Option<&str>, extra_content: Option<Buf
 /// item definition.
 ///
 /// More explanations about spans and how we use them here are provided in the
-/// [`LightSpan::new_in_file`] function documentation about how it works.
 fn write_code(
     out: &mut Buffer,
     src: &str,
@@ -95,7 +90,7 @@ fn write_code(
 ) {
     // This replace allows to fix how the code source with DOS backline characters is displayed.
     let src = src.replace("\r\n", "\n");
-    Classifier::new(&src, edition, context_info.as_ref().map(|c| c.file_span_lo).unwrap_or(0))
+    Classifier::new(&src, edition, context_info.as_ref().map(|c| c.file_span).unwrap_or(DUMMY_SP))
         .highlight(&mut |highlight| {
             match highlight {
                 Highlight::Token { text, class } => string(out, Escape(text), class, &context_info),
@@ -118,14 +113,14 @@ enum Class {
     KeyWord,
     // Keywords that do pointer/reference stuff.
     RefKeyWord,
-    Self_(LightSpan),
+    Self_(Span),
     Op,
     Macro,
     MacroNonTerminal,
     String,
     Number,
     Bool,
-    Ident(LightSpan),
+    Ident(Span),
     Lifetime,
     PreludeTy,
     PreludeVal,
@@ -158,7 +153,7 @@ impl Class {
 
     /// In case this is an item which can be converted into a link to a definition, it'll contain
     /// a "span" (a tuple representing `(lo, hi)` equivalent of `Span`).
-    fn get_span(self) -> Option<LightSpan> {
+    fn get_span(self) -> Option<Span> {
         match self {
             Self::Ident(sp) | Self::Self_(sp) => Some(sp),
             _ => None,
@@ -213,15 +208,14 @@ struct Classifier<'a> {
     in_macro_nonterminal: bool,
     edition: Edition,
     byte_pos: u32,
-    file_span_lo: u32,
+    file_span: Span,
     src: &'a str,
 }
 
 impl<'a> Classifier<'a> {
     /// Takes as argument the source code to HTML-ify, the rust edition to use and the source code
-    /// file "lo" byte which we be used later on by the `span_correspondance_map`. More explanations
-    /// are provided in the [`LightSpan::new_in_file`] function documentation about how it works.
-    fn new(src: &str, edition: Edition, file_span_lo: u32) -> Classifier<'_> {
+    /// file span which will be used later on by the `span_correspondance_map`.
+    fn new(src: &str, edition: Edition, file_span: Span) -> Classifier<'_> {
         let tokens = TokenIter { src }.peekable();
         Classifier {
             tokens,
@@ -230,15 +224,16 @@ impl<'a> Classifier<'a> {
             in_macro_nonterminal: false,
             edition,
             byte_pos: 0,
-            file_span_lo,
+            file_span,
             src,
         }
     }
 
-    /// Convenient wrapper around [`LightSpan::new_in_file`] to prevent passing the `file_span_lo`
-    /// argument every time.
-    fn new_light_span(&self, lo: u32, hi: u32) -> LightSpan {
-        LightSpan::new_in_file(self.file_span_lo, lo, hi)
+    /// Convenient wrapper to create a [`Span`] from a position in the file.
+    fn new_span(&self, lo: u32, text: &str) -> Span {
+        let hi = lo + text.len() as u32;
+        let file_lo = self.file_span.lo();
+        self.file_span.with_lo(file_lo + BytePos(lo)).with_hi(file_lo + BytePos(hi))
     }
 
     /// Concatenate colons and idents as one when possible.
@@ -487,15 +482,13 @@ impl<'a> Classifier<'a> {
                         self.in_macro_nonterminal = false;
                         Class::MacroNonTerminal
                     }
-                    "self" | "Self" => {
-                        Class::Self_(self.new_light_span(before, before + text.len() as u32))
-                    }
-                    _ => Class::Ident(self.new_light_span(before, before + text.len() as u32)),
+                    "self" | "Self" => Class::Self_(self.new_span(before, text)),
+                    _ => Class::Ident(self.new_span(before, text)),
                 },
                 Some(c) => c,
             },
             TokenKind::RawIdent | TokenKind::UnknownPrefix => {
-                Class::Ident(self.new_light_span(before, before + text.len() as u32))
+                Class::Ident(self.new_span(before, text))
             }
             TokenKind::Lifetime { .. } => Class::Lifetime,
         };
@@ -560,7 +553,7 @@ fn string<T: Display>(
                 "self" | "Self" => write!(
                     &mut path,
                     "<span class=\"{}\">{}</span>",
-                    Class::Self_(LightSpan::dummy()).as_html(),
+                    Class::Self_(DUMMY_SP).as_html(),
                     t
                 ),
                 "crate" | "super" => {
diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
@@ -18,8 +18,8 @@ use super::cache::{build_index, ExternalLocation};
 use super::print_item::{full_path, item_path, print_item};
 use super::write_shared::write_shared;
 use super::{
-    collect_spans_and_sources, print_sidebar, settings, AllTypes, LightSpan, LinkFromSrc, NameDoc,
-    StylePath, BASIC_KEYWORDS,
+    collect_spans_and_sources, print_sidebar, settings, AllTypes, LinkFromSrc, NameDoc, StylePath,
+    BASIC_KEYWORDS,
 };
 
 use crate::clean;
@@ -131,7 +131,7 @@ crate struct SharedContext<'tcx> {
 
     /// Correspondance map used to link types used in the source code pages to allow to click on
     /// links to jump to the type's definition.
-    crate span_correspondance_map: FxHashMap<LightSpan, LinkFromSrc>,
+    crate span_correspondance_map: FxHashMap<rustc_span::Span, LinkFromSrc>,
 }
 
 impl SharedContext<'_> {
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
@@ -34,7 +34,7 @@ mod span_map;
 mod write_shared;
 
 crate use context::*;
-crate use span_map::{collect_spans_and_sources, LightSpan, LinkFromSrc};
+crate use span_map::{collect_spans_and_sources, LinkFromSrc};
 
 use std::collections::VecDeque;
 use std::default::Default;
diff --git a/src/librustdoc/html/render/span_map.rs b/src/librustdoc/html/render/span_map.rs
@@ -24,43 +24,6 @@ crate enum LinkFromSrc {
     External(DefId),
 }
 
-/// This struct is used only as index in the `span_map`, not as [`Span`]! `Span`s contain
-/// some extra information (the syntax context) we don't need. **Do not convert this type back to
-/// `Span`!!!**
-#[derive(Clone, Copy, Hash, PartialEq, Eq, Debug)]
-crate struct LightSpan {
-    crate lo: u32,
-    crate hi: u32,
-}
-
-impl LightSpan {
-    /// Before explaining what this method does, some global explanations on rust's `Span`:
-    ///
-    /// Each source code file is stored in the source map in the compiler and has a
-    /// `lo` and a `hi` (lowest and highest bytes in this source map which can be seen as one huge
-    /// string to simplify things). So in this case, this represents the starting byte of the
-    /// current file. It'll be used later on to retrieve the "definition span" from the
-    /// `span_correspondance_map` (which is inside `context`).
-    ///
-    /// This when we transform the "span" we have from reading the input into a "span" which can be
-    /// used as index to the `span_correspondance_map` to get the definition of this item.
-    ///
-    /// So in here, `file_span_lo` is representing the "lo" byte in the global source map, and to
-    /// make our "span" works in there, we simply add `file_span_lo` to our values.
-    crate fn new_in_file(file_span_lo: u32, lo: u32, hi: u32) -> Self {
-        Self { lo: lo + file_span_lo, hi: hi + file_span_lo }
-    }
-
-    crate fn dummy() -> Self {
-        Self { lo: 0, hi: 0 }
-    }
-
-    /// Extra the `lo` and `hi` from the [`Span`] and discard the unused syntax context.
-    fn new_from_span(sp: Span) -> Self {
-        Self { lo: sp.lo().0, hi: sp.hi().0 }
-    }
-}
-
 /// This function will do at most two things:
 ///
 /// 1. Generate a `span` correspondance map which links an item `span` to its definition `span`.
@@ -77,7 +40,7 @@ crate fn collect_spans_and_sources(
     src_root: &Path,
     include_sources: bool,
     generate_link_to_definition: bool,
-) -> (clean::Crate, FxHashMap<PathBuf, String>, FxHashMap<LightSpan, LinkFromSrc>) {
+) -> (clean::Crate, FxHashMap<PathBuf, String>, FxHashMap<Span, LinkFromSrc>) {
     let mut visitor = SpanMapVisitor { tcx, matches: FxHashMap::default() };
 
     if include_sources {
@@ -93,7 +56,7 @@ crate fn collect_spans_and_sources(
 
 struct SpanMapVisitor<'tcx> {
     crate tcx: TyCtxt<'tcx>,
-    crate matches: FxHashMap<LightSpan, LinkFromSrc>,
+    crate matches: FxHashMap<Span, LinkFromSrc>,
 }
 
 impl<'tcx> SpanMapVisitor<'tcx> {
@@ -115,18 +78,12 @@ impl<'tcx> SpanMapVisitor<'tcx> {
         };
         if let Some(span) = self.tcx.hir().res_span(path.res) {
             self.matches.insert(
-                path_span
-                    .map(LightSpan::new_from_span)
-                    .unwrap_or_else(|| LightSpan::new_from_span(path.span)),
+                path_span.unwrap_or_else(|| path.span),
                 LinkFromSrc::Local(clean::Span::new(span)),
             );
         } else if let Some(def_id) = info {
-            self.matches.insert(
-                path_span
-                    .map(LightSpan::new_from_span)
-                    .unwrap_or_else(|| LightSpan::new_from_span(path.span)),
-                LinkFromSrc::External(def_id),
-            );
+            self.matches
+                .insert(path_span.unwrap_or_else(|| path.span), LinkFromSrc::External(def_id));
         }
     }
 }
@@ -163,10 +120,8 @@ impl Visitor<'tcx> for SpanMapVisitor<'tcx> {
             if let Some(node) = self.tcx.hir().find(id) {
                 match node {
                     Node::Item(item) => {
-                        self.matches.insert(
-                            LightSpan::new_from_span(item.ident.span),
-                            LinkFromSrc::Local(clean::Span::new(m.inner)),
-                        );
+                        self.matches
+                            .insert(item.ident.span, LinkFromSrc::Local(clean::Span::new(m.inner)));
                     }
                     _ => {}
                 }
@@ -188,7 +143,7 @@ impl Visitor<'tcx> for SpanMapVisitor<'tcx> {
                     });
                     if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
                         self.matches.insert(
-                            LightSpan::new_from_span(method_span),
+                            method_span,
                             match hir.span_if_local(def_id) {
                                 Some(span) => LinkFromSrc::Local(clean::Span::new(span)),
                                 None => LinkFromSrc::External(def_id),
diff --git a/src/librustdoc/html/sources.rs b/src/librustdoc/html/sources.rs
@@ -111,13 +111,14 @@ impl DocFolder for SourceCollector<'_, '_> {
         if self.cx.include_sources && is_real_and_local(span, sess) {
             let filename = span.filename(sess);
             let span = span.inner();
-            let start_pos = sess.source_map().lookup_source_file(span.lo()).start_pos;
+            let pos = sess.source_map().lookup_source_file(span.lo());
+            let file_span = span.with_lo(pos.start_pos).with_hi(pos.end_pos);
             // If it turns out that we couldn't read this file, then we probably
             // can't read any of the files (generating html output from json or
             // something like that), so just don't include sources for the
             // entire crate. The other option is maintaining this mapping on a
             // per-file basis, but that's probably not worth it...
-            self.cx.include_sources = match self.emit_source(&filename, start_pos.0) {
+            self.cx.include_sources = match self.emit_source(&filename, file_span) {
                 Ok(()) => true,
                 Err(e) => {
                     self.cx.shared.tcx.sess.span_err(
@@ -140,7 +141,11 @@ impl DocFolder for SourceCollector<'_, '_> {
 
 impl SourceCollector<'_, 'tcx> {
     /// Renders the given filename into its corresponding HTML source file.
-    fn emit_source(&mut self, filename: &FileName, file_span_lo: u32) -> Result<(), Error> {
+    fn emit_source(
+        &mut self,
+        filename: &FileName,
+        file_span: rustc_span::Span,
+    ) -> Result<(), Error> {
         let p = match *filename {
             FileName::Real(ref file) => {
                 if let Some(local_path) = file.local_path() {
@@ -200,14 +205,7 @@ impl SourceCollector<'_, 'tcx> {
             &page,
             "",
             |buf: &mut _| {
-                print_src(
-                    buf,
-                    contents,
-                    self.cx.shared.edition(),
-                    file_span_lo,
-                    &self.cx,
-                    &root_path,
-                )
+                print_src(buf, contents, self.cx.shared.edition(), file_span, &self.cx, &root_path)
             },
             &self.cx.shared.style_files,
         );
@@ -250,7 +248,7 @@ fn print_src(
     buf: &mut Buffer,
     s: &str,
     edition: Edition,
-    file_span_lo: u32,
+    file_span: rustc_span::Span,
     context: &Context<'_>,
     root_path: &str,
 ) {
@@ -275,6 +273,6 @@ fn print_src(
         None,
         edition,
         Some(line_numbers),
-        Some(highlight::ContextInfo { context, file_span_lo, root_path }),
+        Some(highlight::ContextInfo { context, file_span, root_path }),
     );
 }
