Switch tokenizer to use a pointer rather than index for position tracking

Cargo.toml

@@ -12,7 +12,7 @@ license = "MPL-2.0"
 edition = "2018"
 rust-version = "1.63"
 
-exclude = ["src/css-parsing-tests/**", "src/big-data-url.css"]
+exclude = ["src/css-parsing-tests/**", "src/big-data-url.css", "src/bootstrap.min.css"]
 
 [dev-dependencies]
 serde_json = "1.0.25"

src/parser.rs

@@ -16,8 +16,8 @@ use std::ops::Range;
 /// Should only be used with the `Parser` instance it came from.
 #[derive(Debug, Clone)]
 pub struct ParserState {
-    pub(crate) position: usize,
-    pub(crate) current_line_start_position: usize,
+    pub(crate) position: SourcePosition,
+    pub(crate) current_line_start_position: SourcePosition,
     pub(crate) current_line_number: u32,
     pub(crate) at_start_of: Option<BlockType>,
 }
@@ -26,15 +26,15 @@ impl ParserState {
     /// The position from the start of the input, counted in UTF-8 bytes.
     #[inline]
     pub fn position(&self) -> SourcePosition {
-        SourcePosition(self.position)
+        self.position
     }
 
     /// The line number and column number
     #[inline]
     pub fn source_location(&self) -> SourceLocation {
         SourceLocation {
             line: self.current_line_number,
-            column: (self.position - self.current_line_start_position + 1) as u32,
+            column: (self.position.0 - self.current_line_start_position.0 + 1) as u32,
         }
     }
 }

src/tests.rs

@@ -828,6 +828,41 @@ fn numeric(b: &mut Bencher) {
     })
 }
 
+#[cfg(feature = "bench")]
+const BOOTSTRAP: &'static str = include_str!("bootstrap.min.css");
+
+#[cfg(feature = "bench")]
+fn tokenize_recursive<'i>(input: &mut Parser<'i, '_>) -> Result<(), ParseError<'i, ()>> {
+    while !input.is_exhausted() {
+        match input.next()? {
+            Token::ParenthesisBlock |
+            Token::SquareBracketBlock |
+            Token::CurlyBracketBlock |
+            Token::Function(..) => {
+                input.parse_nested_block(|input| tokenize_recursive(input))?;
+            },
+            _ => {},
+        }
+    }
+    Ok(())
+}
+
+#[cfg(feature = "bench")]
+#[bench]
+fn bootstrap(b: &mut Bencher) {
+    b.iter(|| {
+        let mut input = ParserInput::new(BOOTSTRAP);
+        let mut input = Parser::new(&mut input);
+        input.look_for_var_or_env_functions();
+
+        let result = tokenize_recursive(&mut input);
+
+        assert!(result.is_ok());
+
+        (result.is_ok(), input.seen_var_or_env_functions())
+    })
+}
+
 struct JsonParser;
 
 #[cfg_attr(all(miri, feature = "skip_long_tests"), ignore)]