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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
//! HTML markup utilities.

use super::Nesting;
use crate::types::parameters::Text;
use std::{
    fmt::{self, Display, Formatter, Write},
    ops::Deref,
};

/// Characters that need to be escaped to be interpreted as text.
pub const ESCAPED_TEXT_CHARACTERS: [(char, &str); 3] =
    [('<', "&lt;"), ('>', "&gt;"), ('&', "&amp;")];

/// Represents a value that can be formatted for HTML.
pub trait Formattable {
    /// Writes formatted value to the formatter.
    fn format(&self, formatter: &mut Formatter, _: Nesting) -> fmt::Result;
}

impl_primitives!(Formattable);
impl_tuples!(Formattable);

impl Formattable for char {
    fn format(&self, formatter: &mut Formatter, _: Nesting) -> fmt::Result {
        if let Some((_, escaped)) =
            ESCAPED_TEXT_CHARACTERS.iter().find(|(c, _)| *c == *self)
        {
            formatter.write_str(escaped)
        } else {
            formatter.write_char(*self)
        }
    }
}

impl Formattable for &'_ str {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.chars()
            .try_for_each(|character| character.format(formatter, nesting))
    }
}

impl Formattable for String {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.as_str().format(formatter, nesting)
    }
}

impl<T: Formattable> Formattable for &'_ [T] {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.iter().try_for_each(|x| x.format(formatter, nesting))
    }
}

impl<T: Formattable> Formattable for Vec<T> {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.as_slice().format(formatter, nesting)
    }
}

impl<T: Formattable + ?Sized> Formattable for Box<T> {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.deref().format(formatter, nesting)
    }
}

/// Represents HTML text. Can be created with [`html`].
#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
#[must_use = "HTML needs to be turned into a `Text` instance"]
pub struct Html<T>(T);

struct Displayable<T>(Html<T>);

/// Creates HTML text.
pub fn html<T: Formattable>(content: T) -> Html<T> {
    Html(content)
}

impl<T: Formattable> Formattable for Html<T> {
    fn format(
        &self,
        formatter: &mut Formatter,
        nesting: Nesting,
    ) -> fmt::Result {
        self.0.format(formatter, nesting)
    }
}

impl<T: Formattable> Display for Displayable<T> {
    fn fmt(&self, formatter: &mut Formatter) -> fmt::Result {
        self.0.format(formatter, Nesting::default())
    }
}

impl<T: Formattable> From<Html<T>> for Text {
    fn from(markup: Html<T>) -> Self {
        let message = Displayable(markup).to_string();
        Self::with_html(message)
    }
}