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, 79 insertions, 11 deletions

diff --git a/src/tokenizer/machine.rs b/src/tokenizer/machine.rs
index fc31a42..e9a3e68 100644
--- a/src/tokenizer/machine.rs
+++ b/src/tokenizer/machine.rs
@@ -1,16 +1,65 @@
-pub(super) mod utils;
+mod utils;
 
 use crate::entities::try_read_character_reference;
 use crate::offset::{Offset, Position};
 use crate::token::AttrValueSyntax;
 use crate::tokenizer::CdataAction;
-use crate::{reader::Reader, Emitter, Error, Tokenizer};
+use crate::{reader::Reader, Emitter, Error};
 use utils::{
     ascii_digit_pat, control_pat, ctostr, noncharacter_pat, surrogate_pat, whitespace_pat,
 };
 
 pub use utils::State;
 
+pub(super) struct Machine<R, O, E> {
+    pub(super) state: State,
+    pub(super) emitter: E,
+    temporary_buffer: String,
+    reader: R,
+    to_reconsume: Stack2<Option<char>>,
+    character_reference_code: u32,
+    return_state: Option<State>,
+    current_tag_name: String,
+    pub(super) last_start_tag_name: String,
+    is_start_tag: bool,
+    /// The reader position before the match block in [`consume`].
+    position_before_match: O,
+    /// * Set to the offset of `<` in [`State::Data`].
+    /// * Set to the offset of `-` in [`State::Comment`].
+    /// * Set to the offset of `&` in [`State::CharacterReference`].
+    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).
+    ///
+    /// [`Tokenizer::set_state`]: super::Tokenizer::set_state
+    pub(crate) naively_switch_state: bool,
+}
+
+impl<R, O, E> Machine<R, O, E>
+where
+    R: Reader + Position<O>,
+    O: Offset,
+    E: Emitter<O>,
+{
+    pub fn new(reader: R, emitter: E) -> Self {
+        Self {
+            reader,
+            emitter,
+            state: State::Data,
+            to_reconsume: Stack2::default(),
+            return_state: None,
+            temporary_buffer: String::new(),
+            character_reference_code: 0,
+            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,
+        }
+    }
+}
+
 pub enum ControlToken {
     Eof,
     Continue,
@@ -18,7 +67,7 @@ pub enum ControlToken {
 }
 
 #[inline]
-pub fn consume<O, R, E>(slf: &mut Tokenizer<R, O, E>) -> Result<ControlToken, R::Error>
+pub(super) fn consume<O, R, E>(slf: &mut Machine<R, O, E>) -> Result<ControlToken, R::Error>
 where
     O: Offset,
     R: Reader + Position<O>,
@@ -1964,15 +2013,8 @@ where
     }
 }
 
-impl<R: Reader + Position<O>, O: Offset, E: Emitter<O>> Tokenizer<R, O, E> {
-    #[inline]
-    fn init_doctype(&mut self) {
-        self.emitter.init_doctype(self.some_offset);
-    }
-}
-
 #[inline]
-pub fn handle_cdata_open<O, R, E>(slf: &mut Tokenizer<R, O, E>, action: CdataAction)
+pub(super) fn handle_cdata_open<O, R, E>(slf: &mut Machine<R, O, E>, action: CdataAction)
 where
     O: Offset,
     R: Reader + Position<O>,
@@ -1989,3 +2031,29 @@ where
         }
     }
 }
+
+// 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
+    }
+}