spans: copy DefaultEmitter to new span module

2 files changed, 266 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index b222193..40f9588 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,6 +9,7 @@ mod error;
 mod machine;
 mod never;
 mod reader;
+mod spans;
 mod tokenizer;
 mod utils;
 
diff --git a/src/spans.rs b/src/spans.rs
new file mode 100644
index 0000000..ea3409c
--- /dev/null
+++ b/src/spans.rs
@@ -0,0 +1,265 @@
+use std::{
+    collections::{BTreeSet, VecDeque},
+    marker::PhantomData,
+    mem,
+};
+
+use crate::{Doctype, Emitter, EndTag, Error, StartTag, Token};
+
+/// The default implementation of [`crate::Emitter`], used to produce ("emit") tokens.
+pub struct DefaultEmitter<S, R> {
+    current_characters: String,
+    current_token: Option<Token<S>>,
+    last_start_tag: String,
+    current_attribute: Option<(String, String)>,
+    seen_attributes: BTreeSet<String>,
+    emitted_tokens: VecDeque<Token<S>>,
+    reader: PhantomData<R>,
+}
+
+impl<S, R> Default for DefaultEmitter<S, R> {
+    fn default() -> Self {
+        DefaultEmitter {
+            current_characters: String::new(),
+            current_token: None,
+            last_start_tag: String::new(),
+            current_attribute: None,
+            seen_attributes: BTreeSet::new(),
+            emitted_tokens: VecDeque::new(),
+            reader: PhantomData::default(),
+        }
+    }
+}
+
+impl<R> DefaultEmitter<(), R> {
+    fn emit_token(&mut self, token: Token<()>) {
+        self.flush_current_characters();
+        self.emitted_tokens.push_front(token);
+    }
+
+    fn flush_current_attribute(&mut self) {
+        if let Some((k, v)) = self.current_attribute.take() {
+            match self.current_token {
+                Some(Token::StartTag(ref mut tag)) => {
+                    let mut error = None;
+                    tag.attributes
+                        .entry(k)
+                        .and_modify(|_| {
+                            error = Some(Error::DuplicateAttribute);
+                        })
+                        .or_insert(v);
+
+                    if let Some(e) = error {
+                        self.emit_error(e);
+                    }
+                }
+                Some(Token::EndTag(_)) => {
+                    if !self.seen_attributes.insert(k) {
+                        self.emit_error(Error::DuplicateAttribute);
+                    }
+                }
+                _ => {
+                    debug_assert!(false);
+                }
+            }
+        }
+    }
+
+    fn flush_current_characters(&mut self) {
+        if self.current_characters.is_empty() {
+            return;
+        }
+
+        let s = mem::take(&mut self.current_characters);
+        self.emit_token(Token::String(s));
+    }
+}
+
+impl<R> Emitter<R> for DefaultEmitter<(), R> {
+    type Token = Token<()>;
+
+    fn set_last_start_tag(&mut self, last_start_tag: Option<&str>) {
+        self.last_start_tag.clear();
+        self.last_start_tag
+            .push_str(last_start_tag.unwrap_or_default());
+    }
+
+    fn emit_eof(&mut self) {
+        self.flush_current_characters();
+    }
+
+    fn emit_error(&mut self, error: Error) {
+        // bypass character flushing in self.emit_token: we don't need the error location to be
+        // that exact
+        self.emitted_tokens.push_front(Token::Error(error));
+    }
+
+    fn pop_token(&mut self) -> Option<Self::Token> {
+        self.emitted_tokens.pop_back()
+    }
+
+    fn emit_string(&mut self, s: &str) {
+        self.current_characters.push_str(s);
+    }
+
+    fn init_start_tag(&mut self, _reader: &R) {
+        self.current_token = Some(Token::StartTag(Default::default()));
+    }
+    fn init_end_tag(&mut self, _reader: &R) {
+        self.current_token = Some(Token::EndTag(Default::default()));
+        self.seen_attributes.clear();
+    }
+
+    fn init_comment(&mut self, _reader: &R) {
+        self.current_token = Some(Token::Comment(String::new()));
+    }
+    fn emit_current_tag(&mut self) {
+        self.flush_current_attribute();
+        let mut token = self.current_token.take().unwrap();
+        match token {
+            Token::EndTag(_) => {
+                if !self.seen_attributes.is_empty() {
+                    self.emit_error(Error::EndTagWithAttributes);
+                }
+                self.seen_attributes.clear();
+            }
+            Token::StartTag(ref mut _tag) => {
+                self.set_last_start_tag(Some(&_tag.name));
+            }
+            _ => debug_assert!(false),
+        }
+        self.emit_token(token);
+    }
+    fn emit_current_comment(&mut self) {
+        let comment = self.current_token.take().unwrap();
+        debug_assert!(matches!(comment, Token::Comment(_)));
+        self.emit_token(comment);
+    }
+
+    fn emit_current_doctype(&mut self) {
+        let doctype = self.current_token.take().unwrap();
+        debug_assert!(matches!(doctype, Token::Doctype(_)));
+        self.emit_token(doctype);
+    }
+
+    fn set_self_closing(&mut self) {
+        let tag = self.current_token.as_mut().unwrap();
+        match tag {
+            Token::StartTag(StartTag {
+                ref mut self_closing,
+                ..
+            }) => {
+                *self_closing = true;
+            }
+            Token::EndTag(_) => {
+                self.emit_error(Error::EndTagWithTrailingSolidus);
+            }
+            _ => {
+                debug_assert!(false);
+            }
+        }
+    }
+    fn set_force_quirks(&mut self) {
+        match self.current_token {
+            Some(Token::Doctype(ref mut doctype)) => doctype.force_quirks = true,
+            _ => debug_assert!(false),
+        }
+    }
+    fn push_tag_name(&mut self, s: &str) {
+        match self.current_token {
+            Some(Token::StartTag(StartTag { ref mut name, .. })) => {
+                name.push_str(s);
+            }
+            Some(Token::EndTag(EndTag { ref mut name, .. })) => {
+                name.push_str(s);
+            }
+            _ => debug_assert!(false),
+        }
+    }
+
+    fn push_comment(&mut self, s: &str) {
+        match self.current_token {
+            Some(Token::Comment(ref mut data)) => data.push_str(s),
+            _ => debug_assert!(false),
+        }
+    }
+
+    fn push_doctype_name(&mut self, s: &str) {
+        match self.current_token {
+            Some(Token::Doctype(ref mut doctype)) => doctype.name.push_str(s),
+            _ => debug_assert!(false),
+        }
+    }
+    fn init_doctype(&mut self, _reader: &R) {
+        self.current_token = Some(Token::Doctype(Doctype {
+            name: String::new(),
+            force_quirks: false,
+            public_identifier: None,
+            system_identifier: None,
+        }));
+    }
+
+    fn init_attribute(&mut self, _reader: &R) {
+        self.flush_current_attribute();
+        self.current_attribute = Some((String::new(), String::new()));
+    }
+    fn push_attribute_name(&mut self, s: &str) {
+        self.current_attribute.as_mut().unwrap().0.push_str(s);
+    }
+    fn push_attribute_value(&mut self, s: &str) {
+        self.current_attribute.as_mut().unwrap().1.push_str(s);
+    }
+    fn set_doctype_public_identifier(&mut self, value: &str) {
+        if let Some(Token::Doctype(Doctype {
+            ref mut public_identifier,
+            ..
+        })) = self.current_token
+        {
+            *public_identifier = Some(value.to_owned());
+        } else {
+            debug_assert!(false);
+        }
+    }
+    fn set_doctype_system_identifier(&mut self, value: &str) {
+        if let Some(Token::Doctype(Doctype {
+            ref mut system_identifier,
+            ..
+        })) = self.current_token
+        {
+            *system_identifier = Some(value.to_owned());
+        } else {
+            debug_assert!(false);
+        }
+    }
+    fn push_doctype_public_identifier(&mut self, s: &str) {
+        if let Some(Token::Doctype(Doctype {
+            public_identifier: Some(ref mut id),
+            ..
+        })) = self.current_token
+        {
+            id.push_str(s);
+        } else {
+            debug_assert!(false);
+        }
+    }
+    fn push_doctype_system_identifier(&mut self, s: &str) {
+        if let Some(Token::Doctype(Doctype {
+            system_identifier: Some(ref mut id),
+            ..
+        })) = self.current_token
+        {
+            id.push_str(s);
+        } else {
+            debug_assert!(false);
+        }
+    }
+
+    fn current_is_appropriate_end_tag_token(&mut self) -> bool {
+        match self.current_token {
+            Some(Token::EndTag(ref tag)) => {
+                !self.last_start_tag.is_empty() && self.last_start_tag == tag.name
+            }
+            _ => false,
+        }
+    }
+}