remove peek_span_src_raw from StringReader

Author: matklad

src/librustc_save_analysis/span_utils.rs

@@ -53,7 +53,7 @@ impl<'a> SpanUtils<'a> {
     pub fn sub_span_of_token(&self, span: Span, tok: TokenKind) -> Option<Span> {
         let mut toks = self.retokenise_span(span);
         loop {
-            let next = toks.real_token();
+            let next = toks.next_token();
             if next == token::Eof {
                 return None;
             }

src/libsyntax/parse/lexer/mod.rs

@@ -38,8 +38,6 @@ pub struct StringReader<'a> {
     crate source_file: Lrc<syntax_pos::SourceFile>,
     /// Stop reading src at this index.
     crate end_src_index: usize,
-    // cached:
-    peek_span_src_raw: Span,
     fatal_errs: Vec<DiagnosticBuilder<'a>>,
     // cache a direct reference to the source text, so that we don't have to
     // retrieve it via `self.source_file.src.as_ref().unwrap()` all the time.
@@ -59,7 +57,7 @@ impl<'a> StringReader<'a> {
         (real, raw)
     }
 
-    fn unwrap_or_abort(&mut self, res: Result<Token, ()>) -> Token {
+    fn unwrap_or_abort<T>(&mut self, res: Result<T, ()>) -> T {
         match res {
             Ok(tok) => tok,
             Err(_) => {
@@ -69,36 +67,52 @@ impl<'a> StringReader<'a> {
         }
     }
 
-    fn next_token(&mut self) -> Token where Self: Sized {
-        let res = self.try_next_token();
-        self.unwrap_or_abort(res)
-    }
-
     /// Returns the next token. EFFECT: advances the string_reader.
     pub fn try_next_token(&mut self) -> Result<Token, ()> {
-        assert!(self.fatal_errs.is_empty());
-        self.advance_token()
+        let (token, _raw_span) = self.try_next_token_with_raw_span()?;
+        Ok(token)
     }
 
-    fn try_real_token(&mut self) -> Result<Token, ()> {
-        let mut t = self.try_next_token()?;
+    pub fn next_token(&mut self) -> Token {
+        let res = self.try_next_token();
+        self.unwrap_or_abort(res)
+    }
+
+    fn try_real_token(&mut self) -> Result<(Token, Span), ()> {
         loop {
-            match t.kind {
-                token::Whitespace | token::Comment | token::Shebang(_) => {
-                    t = self.try_next_token()?;
-                }
-                _ => break,
+            let t = self.try_next_token_with_raw_span()?;
+            match t.0.kind {
+                token::Whitespace | token::Comment | token::Shebang(_) => continue,
+                _ => return Ok(t),
             }
         }
-
-        Ok(t)
     }
 
-    pub fn real_token(&mut self) -> Token {
+    fn real_token(&mut self) -> (Token, Span) {
         let res = self.try_real_token();
         self.unwrap_or_abort(res)
     }
 
+    fn try_next_token_with_raw_span(&mut self) -> Result<(Token, Span), ()> {
+        assert!(self.fatal_errs.is_empty());
+        match self.scan_whitespace_or_comment() {
+            Some(comment) => {
+                let raw_span = comment.span;
+                Ok((comment, raw_span))
+            }
+            None => {
+                let (kind, start_pos, end_pos) = if self.is_eof() {
+                    (token::Eof, self.source_file.end_pos, self.source_file.end_pos)
+                } else {
+                    let start_pos = self.pos;
+                    (self.next_token_inner()?, start_pos, self.pos)
+                };
+                let (real, raw) = self.mk_sp_and_raw(start_pos, end_pos);
+                Ok((Token::new(kind, real), raw))
+            }
+        }
+    }
+
     #[inline]
     fn is_eof(&self) -> bool {
         self.ch.is_none()
@@ -141,7 +155,6 @@ impl<'a> StringReader<'a> {
                override_span: Option<Span>) -> Self {
         let mut sr = StringReader::new_raw_internal(sess, source_file, override_span);
         sr.bump();
-
         sr
     }
 
@@ -162,7 +175,6 @@ impl<'a> StringReader<'a> {
             ch: Some('\n'),
             source_file,
             end_src_index: src.len(),
-            peek_span_src_raw: syntax_pos::DUMMY_SP,
             src,
             fatal_errs: Vec::new(),
             override_span,
@@ -172,12 +184,8 @@ impl<'a> StringReader<'a> {
     pub fn new_or_buffered_errs(sess: &'a ParseSess,
                                 source_file: Lrc<syntax_pos::SourceFile>,
                                 override_span: Option<Span>) -> Result<Self, Vec<Diagnostic>> {
-        let mut sr = StringReader::new_raw(sess, source_file, override_span);
-        if sr.advance_token().is_err() {
-            Err(sr.buffer_fatal_errors())
-        } else {
-            Ok(sr)
-        }
+        let sr = StringReader::new_raw(sess, source_file, override_span);
+        Ok(sr)
     }
 
     pub fn retokenize(sess: &'a ParseSess, mut span: Span) -> Self {
@@ -197,11 +205,6 @@ impl<'a> StringReader<'a> {
 
         sr.bump();
 
-        if sr.advance_token().is_err() {
-            sr.emit_fatal_errors();
-            FatalError.raise();
-        }
-
         sr
     }
 
@@ -257,28 +260,6 @@ impl<'a> StringReader<'a> {
         self.sess.span_diagnostic.struct_span_fatal(self.mk_sp(from_pos, to_pos), &m[..])
     }
 
-    /// Advance peek_token to refer to the next token, and
-    /// possibly update the interner.
-    fn advance_token(&mut self) -> Result<Token, ()> {
-        match self.scan_whitespace_or_comment() {
-            Some(comment) => {
-                self.peek_span_src_raw = comment.span;
-                Ok(comment)
-            }
-            None => {
-                let (kind, start_pos, end_pos) = if self.is_eof() {
-                    (token::Eof, self.source_file.end_pos, self.source_file.end_pos)
-                } else {
-                    let start_pos = self.pos;
-                    (self.next_token_inner()?, start_pos, self.pos)
-                };
-                let (real, raw) = self.mk_sp_and_raw(start_pos, end_pos);
-                self.peek_span_src_raw = raw;
-                Ok(Token::new(kind, real))
-            }
-        }
-    }
-
     #[inline]
     fn src_index(&self, pos: BytePos) -> usize {
         (pos - self.source_file.start_pos).to_usize()
@@ -1447,12 +1428,7 @@ mod tests {
                  teststr: String)
                  -> StringReader<'a> {
         let sf = sm.new_source_file(PathBuf::from(teststr.clone()).into(), teststr);
-        let mut sr = StringReader::new_raw(sess, sf, None);
-        if sr.advance_token().is_err() {
-            sr.emit_fatal_errors();
-            FatalError.raise();
-        }
-        sr
+        StringReader::new_raw(sess, sf, None)
     }
 
     #[test]

src/libsyntax/parse/lexer/tokentrees.rs

@@ -1,4 +1,4 @@
-use syntax_pos::Span;
+use syntax_pos::{Span, DUMMY_SP};
 
 use crate::print::pprust::token_to_string;
 use crate::parse::lexer::{StringReader, UnmatchedBrace};
@@ -11,6 +11,7 @@ impl<'a> StringReader<'a> {
         let mut tt_reader = TokenTreesReader {
             string_reader: self,
             token: Token::dummy(),
+            raw_span: DUMMY_SP,
             open_braces: Vec::new(),
             unmatched_braces: Vec::new(),
             matching_delim_spans: Vec::new(),
@@ -24,6 +25,7 @@ impl<'a> StringReader<'a> {
 struct TokenTreesReader<'a> {
     string_reader: StringReader<'a>,
     token: Token,
+    raw_span: Span,
     /// Stack of open delimiters and their spans. Used for error message.
     open_braces: Vec<(token::DelimToken, Span)>,
     unmatched_braces: Vec<UnmatchedBrace>,
@@ -206,18 +208,17 @@ impl<'a> TokenTreesReader<'a> {
                 // Note that testing for joint-ness here is done via the raw
                 // source span as the joint-ness is a property of the raw source
                 // rather than wanting to take `override_span` into account.
-                // Additionally, we actually check if the *next* pair of tokens
-                // is joint, but this is equivalent to checking the current pair.
-                let raw = self.string_reader.peek_span_src_raw;
+                let raw_span = self.raw_span;
                 self.real_token();
-                let is_joint = raw.hi() == self.string_reader.peek_span_src_raw.lo()
-                    && self.token.is_op();
+                let is_joint = raw_span.hi() == self.raw_span.lo() && self.token.is_op();
                 Ok((tt, if is_joint { Joint } else { NonJoint }))
             }
         }
     }
 
     fn real_token(&mut self) {
-        self.token = self.string_reader.real_token();
+        let (token, raw_span) = self.string_reader.real_token();
+        self.token = token;
+        self.raw_span = raw_span;
     }
 }