1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100

//! Entity and numeric character references
//!
//! `{`, `¯`, `"`
//!
//! <https://spec.commonmark.org/0.30/#entity-and-numeric-character-references>
use once_cell::sync::Lazy;
use regex::Regex;
use crate::{MarkdownIt, Node};
use crate::common::utils::{get_entity_from_str, is_valid_entity_code};
use crate::parser::inline::{InlineRule, InlineState, TextSpecial};

pub fn add(md: &mut MarkdownIt) {
    md.inline.add_rule::<EntityScanner>();
}

static DIGITAL_RE : Lazy<Regex> = Lazy::new(|| {
    Regex::new("(?i)^&#((?:x[a-f0-9]{1,6}|[0-9]{1,7}));").unwrap()
});

static NAMED_RE : Lazy<Regex> = Lazy::new(|| {
    Regex::new("(?i)^&([a-z][a-z0-9]{1,31});").unwrap()
});

#[doc(hidden)]
pub struct EntityScanner;
impl InlineRule for EntityScanner {
    const MARKER: char = '&';

    fn run(state: &mut InlineState, silent: bool) -> bool {
        let mut chars = state.src[state.pos..state.pos_max].chars();
        if chars.next().unwrap() != '&' { return false; }

        if let Some('#') = chars.next() {
            parse_digital_entity(state, silent)
        } else {
            parse_named_entity(state, silent)
        }
    }
}

fn parse_digital_entity(state: &mut InlineState, silent: bool) -> bool {
    if let Some(capture) = DIGITAL_RE.captures(&state.src[state.pos..]) {
        let entity_len = &capture[0].len();
        if !silent {
            let entity = &capture[1];
            #[allow(clippy::from_str_radix_10)]
            let code = if entity.starts_with('x') || entity.starts_with('X') {
                u32::from_str_radix(&entity[1..], 16).unwrap()
            } else {
                u32::from_str_radix(entity, 10).unwrap()
            };

            let content_str = if is_valid_entity_code(code) {
                char::from_u32(code).unwrap().into()
            } else {
                '\u{FFFD}'.into()
            };

            let markup_str = capture[0].to_owned();

            let mut node = Node::new(TextSpecial {
                content: content_str,
                markup: markup_str,
                info: "entity",
            });
            node.srcmap = state.get_map(state.pos, state.pos + entity_len);
            state.node.children.push(node);
        }
        state.pos += entity_len;
        true
    } else {
        false
    }
}

fn parse_named_entity(state: &mut InlineState, silent: bool) -> bool {
    if let Some(capture) = NAMED_RE.captures(&state.src[state.pos..]) {
        if let Some(str) = get_entity_from_str(&capture[0]) {
            let entity_len = &capture[0].len();
            if !silent {
                let markup_str = capture[0].to_owned();
                let content_str = (*str).to_owned();

                let mut node = Node::new(TextSpecial {
                    content: content_str,
                    markup: markup_str,
                    info: "entity",
                });
                node.srcmap = state.get_map(state.pos, state.pos + entity_len);
                state.node.children.push(node);
            }
            state.pos += entity_len;
            true
        } else {
            false
        }
    } else {
        false
    }
}