refactor: proxy emit_string calls through utils

This is done separately so that the next commit has a cleaner diff.

2 files changed, 80 insertions, 62 deletions

diff --git a/src/tokenizer/machine.rs b/src/tokenizer/machine.rs
index e9a3e68..8b09aa7 100644
--- a/src/tokenizer/machine.rs
+++ b/src/tokenizer/machine.rs
@@ -105,11 +105,11 @@ where
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\0");
+                slf.emit_char('\0');
                 Ok(ControlToken::Continue)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             None => Ok(ControlToken::Eof),
@@ -126,11 +126,11 @@ where
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             None => Ok(ControlToken::Eof),
@@ -142,11 +142,11 @@ where
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             None => Ok(ControlToken::Eof),
@@ -158,11 +158,11 @@ where
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             None => Ok(ControlToken::Eof),
@@ -170,11 +170,11 @@ where
         State::PlainText => match slf.read_char()? {
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             None => Ok(ControlToken::Eof),
@@ -203,13 +203,13 @@ where
             }
             None => {
                 slf.emit_error(Error::EofBeforeTagName);
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 Ok(ControlToken::Eof)
             }
             c @ Some(_) => {
                 slf.emit_error(Error::InvalidFirstCharacterOfTagName);
                 slf.state = State::Data;
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
             }
@@ -228,7 +228,7 @@ where
             }
             None => {
                 slf.emit_error(Error::EofBeforeTagName);
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 Ok(ControlToken::Eof)
             }
             Some(x) => {
@@ -277,7 +277,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::RcData;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -291,7 +291,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.state = State::RcData;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -317,7 +317,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.flush_buffer_characters();
 
                 slf.state = State::RcData;
@@ -332,7 +332,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::RawText;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -346,7 +346,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.state = State::RawText;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -372,7 +372,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.flush_buffer_characters();
 
                 slf.state = State::RawText;
@@ -388,11 +388,11 @@ where
             }
             Some('!') => {
                 slf.state = State::ScriptDataEscapeStart;
-                slf.emitter.emit_string("<!");
+                slf.emit_chars(b"<!");
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::ScriptData;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -406,7 +406,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.state = State::ScriptData;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -432,7 +432,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.flush_buffer_characters();
                 slf.state = State::Data;
                 slf.unread_char(c);
@@ -442,7 +442,7 @@ where
         State::ScriptDataEscapeStart => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataEscapeStartDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             c => {
@@ -454,7 +454,7 @@ where
         State::ScriptDataEscapeStartDash => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataEscapedDashDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             c => {
@@ -466,7 +466,7 @@ where
         State::ScriptDataEscaped => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataEscapedDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
@@ -475,7 +475,7 @@ where
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -483,14 +483,14 @@ where
                 Ok(ControlToken::Eof)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
         State::ScriptDataEscapedDash => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataEscapedDashDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
@@ -500,7 +500,7 @@ where
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
                 slf.state = State::ScriptDataEscaped;
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -509,13 +509,13 @@ where
             }
             Some(x) => {
                 slf.state = State::ScriptDataEscaped;
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
         State::ScriptDataEscapedDashDash => match slf.read_char()? {
             Some('-') => {
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
@@ -524,13 +524,13 @@ where
             }
             Some('>') => {
                 slf.state = State::ScriptData;
-                slf.emitter.emit_string(">");
+                slf.emit_char('>');
                 Ok(ControlToken::Continue)
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
                 slf.state = State::ScriptDataEscaped;
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -539,7 +539,7 @@ where
             }
             Some(x) => {
                 slf.state = State::ScriptDataEscaped;
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
@@ -551,13 +551,13 @@ where
             }
             Some(x) if x.is_ascii_alphabetic() => {
                 slf.temporary_buffer.clear();
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::ScriptDataDoubleEscapeStart;
                 slf.unread_char(Some(x));
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::ScriptDataEscaped;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -571,7 +571,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.unread_char(c);
                 slf.state = State::ScriptDataEscaped;
                 Ok(ControlToken::Continue)
@@ -597,7 +597,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("</");
+                slf.emit_chars(b"</");
                 slf.flush_buffer_characters();
                 slf.state = State::ScriptDataEscaped;
                 slf.unread_char(c);
@@ -611,12 +611,12 @@ where
                 } else {
                     slf.state = State::ScriptDataEscaped;
                 }
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             Some(x) if x.is_ascii_alphabetic() => {
                 slf.temporary_buffer.push(x.to_ascii_lowercase());
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             c => {
@@ -628,17 +628,17 @@ where
         State::ScriptDataDoubleEscaped => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataDoubleEscapedDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
                 slf.state = State::ScriptDataDoubleEscapedLessThanSign;
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 Ok(ControlToken::Continue)
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -646,25 +646,25 @@ where
                 Ok(ControlToken::Eof)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
         State::ScriptDataDoubleEscapedDash => match slf.read_char()? {
             Some('-') => {
                 slf.state = State::ScriptDataDoubleEscapedDashDash;
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
                 slf.state = State::ScriptDataDoubleEscapedLessThanSign;
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 Ok(ControlToken::Continue)
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
                 slf.state = State::ScriptDataDoubleEscaped;
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -673,29 +673,29 @@ where
             }
             Some(x) => {
                 slf.state = State::ScriptDataDoubleEscaped;
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
         State::ScriptDataDoubleEscapedDashDash => match slf.read_char()? {
             Some('-') => {
-                slf.emitter.emit_string("-");
+                slf.emit_char('-');
                 Ok(ControlToken::Continue)
             }
             Some('<') => {
-                slf.emitter.emit_string("<");
+                slf.emit_char('<');
                 slf.state = State::ScriptDataDoubleEscapedLessThanSign;
                 Ok(ControlToken::Continue)
             }
             Some('>') => {
-                slf.emitter.emit_string(">");
+                slf.emit_char('>');
                 slf.state = State::ScriptData;
                 Ok(ControlToken::Continue)
             }
             Some('\0') => {
                 slf.emit_error(Error::UnexpectedNullCharacter);
                 slf.state = State::ScriptDataDoubleEscaped;
-                slf.emitter.emit_string("\u{fffd}");
+                slf.emit_char('\u{fffd}');
                 Ok(ControlToken::Continue)
             }
             None => {
@@ -704,7 +704,7 @@ where
             }
             Some(x) => {
                 slf.state = State::ScriptDataDoubleEscaped;
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
@@ -712,7 +712,7 @@ where
             Some('/') => {
                 slf.temporary_buffer.clear();
                 slf.state = State::ScriptDataDoubleEscapeEnd;
-                slf.emitter.emit_string("/");
+                slf.emit_char('/');
                 Ok(ControlToken::Continue)
             }
             c => {
@@ -729,12 +729,12 @@ where
                     slf.state = State::ScriptDataDoubleEscaped;
                 }
 
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             Some(x) if x.is_ascii_alphabetic() => {
                 slf.temporary_buffer.push(x.to_ascii_lowercase());
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
             c => {
@@ -1741,7 +1741,7 @@ where
                 Ok(ControlToken::Eof)
             }
             Some(x) => {
-                slf.emitter.emit_string(ctostr!(x));
+                slf.emit_char(x);
                 Ok(ControlToken::Continue)
             }
         },
@@ -1751,7 +1751,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("]");
+                slf.emit_char(']');
                 slf.state = State::CdataSection;
                 slf.unread_char(c);
                 Ok(ControlToken::Continue)
@@ -1759,7 +1759,7 @@ where
         },
         State::CdataSectionEnd => match slf.read_char()? {
             Some(']') => {
-                slf.emitter.emit_string("]");
+                slf.emit_char(']');
                 Ok(ControlToken::Continue)
             }
             Some('>') => {
@@ -1767,7 +1767,7 @@ where
                 Ok(ControlToken::Continue)
             }
             c => {
-                slf.emitter.emit_string("]]");
+                slf.emit_chars(b"]]");
                 slf.unread_char(c);
                 slf.state = State::CdataSection;
                 Ok(ControlToken::Continue)
@@ -1846,7 +1846,7 @@ where
                 if slf.is_consumed_as_part_of_an_attribute() {
                     slf.emitter.push_attribute_value(ctostr!(x));
                 } else {
-                    slf.emitter.emit_string(ctostr!(x));
+                    slf.emit_char(x);
                 }
 
                 Ok(ControlToken::Continue)
diff --git a/src/tokenizer/machine/utils.rs b/src/tokenizer/machine/utils.rs
index 6e45f4d..d96e50b 100644
--- a/src/tokenizer/machine/utils.rs
+++ b/src/tokenizer/machine/utils.rs
@@ -13,6 +13,24 @@ where
     O: Offset,
     E: Emitter<O>,
 {
+    /// Emits the given character as a character token.
+    #[inline]
+    pub(super) fn emit_char(&mut self, c: char) {
+        self.emitter.emit_string(ctostr!(c));
+    }
+
+    /// Emits every byte of the given byte slice as a character token.
+    ///
+    /// (We're operating on bytes to enable compiler optimization,
+    /// since [`str::chars`] isn't `const`.)
+    #[inline]
+    pub(super) fn emit_chars(&mut self, s: &[u8]) {
+        self.emitter.emit_string(
+            // this unsafe block is only temporary and will be removed in the next commit
+            unsafe { std::str::from_utf8_unchecked(s) },
+        );
+    }
+
     #[inline]
     pub(crate) fn emit_error(&mut self, error: Error) {
         let span = match error {