refactor: move machine impl details to machine module

This commit separates the public API (the "Tokenizer")
from the internal implementation (the "Machine")
to make the code more readable.

1 files changed, 18 insertions, 245 deletions

diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index 6f698f6..7c38e49 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -1,41 +1,13 @@
-mod machine;
+pub(crate) mod machine;
 
-use crate::naive_parser::naive_next_state;
 use crate::offset::{Offset, Position};
 use crate::reader::{IntoReader, Reader};
-use crate::{Emitter, Error};
-use machine::utils::{control_pat, noncharacter_pat, surrogate_pat};
+use crate::Emitter;
 use machine::ControlToken;
 
 #[cfg(feature = "integration-tests")]
 pub use machine::State as InternalState;
 
-// this is a stack that can hold 0 to 2 Ts
-#[derive(Debug, Default, Clone, Copy)]
-struct Stack2<T: Copy>(Option<(T, Option<T>)>);
-
-impl<T: Copy> Stack2<T> {
-    #[inline]
-    fn push(&mut self, c: T) {
-        self.0 = match self.0 {
-            None => Some((c, None)),
-            Some((c1, None)) => Some((c1, Some(c))),
-            Some((_c1, Some(_c2))) => panic!("stack full!"),
-        }
-    }
-
-    #[inline]
-    fn pop(&mut self) -> Option<T> {
-        let (new_self, rv) = match self.0 {
-            Some((c1, Some(c2))) => (Some((c1, None)), Some(c2)),
-            Some((c1, None)) => (None, Some(c1)),
-            None => (None, None),
-        };
-        self.0 = new_self;
-        rv
-    }
-}
-
 /// An HTML tokenizer.
 ///
 /// # Warning
@@ -56,27 +28,9 @@ impl<T: Copy> Stack2<T> {
 ///
 /// [`NaiveParser`]: crate::NaiveParser
 /// [tree construction]: https://html.spec.whatwg.org/multipage/parsing.html#tree-construction
-pub struct Tokenizer<R: Reader, O, E: Emitter<O>> {
+pub struct Tokenizer<R, O, E> {
+    machine: machine::Machine<R, O, E>,
     eof: bool,
-    pub(crate) state: machine::State,
-    pub(crate) emitter: E,
-    pub(crate) temporary_buffer: String,
-    pub(crate) reader: R,
-    to_reconsume: Stack2<Option<char>>,
-    pub(crate) character_reference_code: u32,
-    pub(crate) return_state: Option<machine::State>,
-    current_tag_name: String,
-    last_start_tag_name: String,
-    is_start_tag: bool,
-    /// The reader position before the match block in [`machine::consume`].
-    pub(crate) position_before_match: O,
-    /// * Set to the offset of `<` in [`machine::State::Data`].
-    /// * Set to the offset of `-` in [`machine::State::Comment`].
-    /// * Set to the offset of `&` in [`machine::State::CharacterReference`].
-    pub(crate) some_offset: O,
-    /// This boolean flag exists so that the [`NaiveParser`](crate::NaiveParser) can work with any [`Emitter`]
-    /// (it cannot call [`Tokenizer::set_state`] using the emitted start tags since they can be of an arbitrary type).
-    pub(crate) naively_switch_state: bool,
 }
 
 impl<R: Reader + Position<O>, O: Offset, E: Emitter<O>> Tokenizer<R, O, E> {
@@ -88,20 +42,8 @@ impl<R: Reader + Position<O>, O: Offset, E: Emitter<O>> Tokenizer<R, O, E> {
     /// [tree construction]: https://html.spec.whatwg.org/multipage/parsing.html#tree-construction
     pub fn new<'a>(reader: impl IntoReader<'a, Reader = R>, emitter: E) -> Self {
         Tokenizer {
-            reader: reader.into_reader(),
-            emitter,
-            state: machine::State::Data,
-            to_reconsume: Stack2::default(),
-            return_state: None,
-            temporary_buffer: String::new(),
-            character_reference_code: 0,
+            machine: machine::Machine::new(reader.into_reader(), emitter),
             eof: false,
-            current_tag_name: String::new(),
-            last_start_tag_name: String::new(),
-            is_start_tag: false,
-            position_before_match: O::default(),
-            some_offset: O::default(),
-            naively_switch_state: false,
         }
     }
 
@@ -114,12 +56,12 @@ impl<R: Reader + Position<O>, O: Offset, E: Emitter<O>> Tokenizer<R, O, E> {
     ///
     /// [Markup declaration open state]: https://html.spec.whatwg.org/multipage/parsing.html#markup-declaration-open-state
     pub fn handle_cdata_open(&mut self, action: CdataAction) {
-        machine::handle_cdata_open(self, action);
+        machine::handle_cdata_open(&mut self.machine, action);
     }
 
     /// Returns a mutable reference to the emitter.
     pub fn emitter_mut(&mut self) -> &mut E {
-        &mut self.emitter
+        &mut self.machine.emitter
     }
 }
 
@@ -197,185 +139,12 @@ impl<R: Reader + Position<O>, O: Offset, E: Emitter<O>> Tokenizer<R, O, E> {
     /// Only available with the `integration-tests` feature which is not public API.
     #[cfg(feature = "integration-tests")]
     pub fn set_internal_state(&mut self, state: InternalState) {
-        self.state = state;
+        self.machine.state = state;
     }
 
     /// Set the statemachine to start/continue in the given state.
     pub fn set_state(&mut self, state: State) {
-        self.state = state.into();
-    }
-
-    /// Just a helper method for the machine.
-    #[inline]
-    pub(crate) fn emit_error(&mut self, error: Error) {
-        let span = match error {
-            Error::EofBeforeTagName
-            | Error::EofInCdata
-            | Error::EofInComment
-            | Error::EofInDoctype
-            | Error::EofInScriptHtmlCommentLikeText
-            | Error::EofInTag
-            | Error::MissingSemicolonAfterCharacterReference => {
-                self.reader.position()..self.reader.position()
-            }
-            Error::AbsenceOfDigitsInNumericCharacterReference
-            | Error::NullCharacterReference
-            | Error::CharacterReferenceOutsideUnicodeRange
-            | Error::SurrogateCharacterReference
-            | Error::NoncharacterCharacterReference
-            | Error::ControlCharacterReference
-            | Error::UnknownNamedCharacterReference => self.some_offset..self.reader.position(),
-
-            _ => self.position_before_match..self.reader.position(),
-        };
-        self.emitter.report_error(error, span);
-    }
-
-    /// Assuming the _current token_ is an end tag, return true if all of these hold. Return false otherwise.
-    ///
-    /// * the _last start tag_ exists
-    /// * the current end tag token's name equals to the last start tag's name.
-    ///
-    /// See also WHATWG's definition of [appropriate end tag token].
-    ///
-    /// [appropriate end tag token]: https://html.spec.whatwg.org/multipage/parsing.html#appropriate-end-tag-token
-    #[inline]
-    pub(crate) fn current_end_tag_is_appropriate(&mut self) -> bool {
-        self.current_tag_name == self.last_start_tag_name
-    }
-
-    #[inline]
-    pub(crate) fn init_start_tag(&mut self) {
-        self.emitter
-            .init_start_tag(self.some_offset, self.position_before_match);
-        self.current_tag_name.clear();
-        self.is_start_tag = true;
-    }
-
-    #[inline]
-    pub(crate) fn init_end_tag(&mut self) {
-        self.emitter
-            .init_end_tag(self.some_offset, self.position_before_match);
-        self.current_tag_name.clear();
-        self.is_start_tag = false;
-    }
-
-    #[inline]
-    pub(crate) fn push_tag_name(&mut self, s: &str) {
-        self.emitter.push_tag_name(s);
-        self.current_tag_name.push_str(s);
-    }
-
-    #[inline]
-    pub(crate) fn emit_current_tag(&mut self) {
-        self.emitter.emit_current_tag(self.reader.position());
-        if self.is_start_tag {
-            if self.naively_switch_state {
-                self.state = naive_next_state(&self.current_tag_name).into();
-            }
-            std::mem::swap(&mut self.last_start_tag_name, &mut self.current_tag_name);
-        }
-    }
-
-    #[inline]
-    pub(crate) fn unread_char(&mut self, c: Option<char>) {
-        self.to_reconsume.push(c);
-    }
-
-    #[inline]
-    fn validate_char(&mut self, c: char) {
-        match c as u32 {
-            surrogate_pat!() => {
-                self.emit_error(Error::SurrogateInInputStream);
-            }
-            noncharacter_pat!() => {
-                self.emit_error(Error::NoncharacterInInputStream);
-            }
-            // control without whitespace or nul
-            x @ control_pat!()
-                if !matches!(x, 0x0000 | 0x0009 | 0x000a | 0x000c | 0x000d | 0x0020) =>
-            {
-                self.emit_error(Error::ControlCharacterInInputStream);
-            }
-            _ => (),
-        }
-    }
-
-    pub(crate) fn read_char(&mut self) -> Result<Option<char>, R::Error> {
-        let (c_res, reconsumed) = match self.to_reconsume.pop() {
-            Some(c) => (Ok(c), true),
-            None => (self.reader.read_char(), false),
-        };
-
-        let mut c = match c_res {
-            Ok(Some(c)) => c,
-            res => return res,
-        };
-
-        if c == '\r' {
-            c = '\n';
-            let c2 = self.reader.read_char()?;
-            if c2 != Some('\n') {
-                self.unread_char(c2);
-            }
-        }
-
-        if !reconsumed {
-            self.validate_char(c);
-        }
-
-        Ok(Some(c))
-    }
-
-    #[inline]
-    pub(crate) fn try_read_string(
-        &mut self,
-        mut s: &str,
-        case_sensitive: bool,
-    ) -> Result<bool, R::Error> {
-        debug_assert!(!s.is_empty());
-
-        let to_reconsume_bak = self.to_reconsume;
-        let mut chars = s.chars();
-        while let Some(c) = self.to_reconsume.pop() {
-            if let (Some(x), Some(x2)) = (c, chars.next()) {
-                if x == x2 || (!case_sensitive && x.to_ascii_lowercase() == x2.to_ascii_lowercase())
-                {
-                    s = &s[x.len_utf8()..];
-                    continue;
-                }
-            }
-
-            self.to_reconsume = to_reconsume_bak;
-            return Ok(false);
-        }
-
-        self.reader.try_read_string(s, case_sensitive)
-    }
-
-    pub(crate) fn is_consumed_as_part_of_an_attribute(&self) -> bool {
-        matches!(
-            self.return_state,
-            Some(
-                machine::State::AttributeValueDoubleQuoted
-                    | machine::State::AttributeValueSingleQuoted
-                    | machine::State::AttributeValueUnquoted
-            )
-        )
-    }
-
-    pub(crate) fn flush_code_points_consumed_as_character_reference(&mut self) {
-        if self.is_consumed_as_part_of_an_attribute() {
-            self.emitter.push_attribute_value(&self.temporary_buffer);
-            self.temporary_buffer.clear();
-        } else {
-            self.flush_buffer_characters();
-        }
-    }
-
-    pub(crate) fn flush_buffer_characters(&mut self) {
-        self.emitter.emit_string(&self.temporary_buffer);
-        self.temporary_buffer.clear();
+        self.machine.state = state.into();
     }
 }
 
@@ -389,7 +158,7 @@ where
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
-            if let Some(token) = self.emitter.next() {
+            if let Some(token) = self.machine.emitter.next() {
                 return Some(Ok(Event::Token(token)));
             }
 
@@ -397,12 +166,12 @@ where
                 return None;
             }
 
-            match machine::consume(self) {
+            match machine::consume(&mut self.machine) {
                 Err(e) => return Some(Err(e)),
                 Ok(ControlToken::Continue) => (),
                 Ok(ControlToken::Eof) => {
                     self.eof = true;
-                    self.emitter.emit_eof();
+                    self.machine.emitter.emit_eof();
                 }
                 Ok(ControlToken::CdataOpen) => return Some(Ok(Event::CdataOpen)),
             }
@@ -411,12 +180,16 @@ where
 }
 
 impl<R: Reader, O, E: Emitter<O>> Tokenizer<R, O, E> {
+    pub(crate) fn enable_naive_state_switching(&mut self) {
+        self.machine.naively_switch_state = true;
+    }
+
     /// Test-internal function to override internal state.
     ///
     /// Only available with the `integration-tests` feature which is not public API.
     #[cfg(feature = "integration-tests")]
     pub fn set_last_start_tag(&mut self, last_start_tag: &str) {
-        self.last_start_tag_name.clear();
-        self.last_start_tag_name.push_str(last_start_tag);
+        self.machine.last_start_tag_name.clear();
+        self.machine.last_start_tag_name.push_str(last_start_tag);
     }
 }