lightningcss/rules/
media.rs

1//! The `@media` rule.
2
3use super::Location;
4use super::{CssRuleList, MinifyContext};
5use crate::error::{MinifyError, PrinterError};
6use crate::media_query::MediaList;
7use crate::parser::DefaultAtRule;
8use crate::printer::Printer;
9use crate::traits::ToCss;
10#[cfg(feature = "visitor")]
11use crate::visitor::Visit;
12
13/// A [@media](https://drafts.csswg.org/css-conditional-3/#at-media) rule.
14#[derive(Debug, PartialEq, Clone)]
15#[cfg_attr(feature = "visitor", derive(Visit))]
16#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
17#[cfg_attr(feature = "jsonschema", derive(schemars::JsonSchema))]
18#[cfg_attr(feature = "into_owned", derive(static_self::IntoOwned))]
19pub struct MediaRule<'i, R = DefaultAtRule> {
20  /// The media query list.
21  #[cfg_attr(feature = "serde", serde(borrow))]
22  pub query: MediaList<'i>,
23  /// The rules within the `@media` rule.
24  pub rules: CssRuleList<'i, R>,
25  /// The location of the rule in the source file.
26  #[cfg_attr(feature = "visitor", skip_visit)]
27  pub loc: Location,
28}
29
30impl<'i, T: Clone> MediaRule<'i, T> {
31  pub(crate) fn minify(
32    &mut self,
33    context: &mut MinifyContext<'_, 'i>,
34    parent_is_unused: bool,
35  ) -> Result<bool, MinifyError> {
36    self.rules.minify(context, parent_is_unused)?;
37
38    if let Some(custom_media) = &context.custom_media {
39      self.query.transform_custom_media(self.loc, custom_media)?;
40    }
41
42    self.query.transform_resolution(context.targets.current);
43    Ok(self.rules.0.is_empty() || self.query.never_matches())
44  }
45}
46
47impl<'a, 'i, T: ToCss> ToCss for MediaRule<'i, T> {
48  fn to_css<W>(&self, dest: &mut Printer<W>) -> Result<(), PrinterError>
49  where
50    W: std::fmt::Write,
51  {
52    // If the media query always matches, we can just output the nested rules.
53    if dest.minify && self.query.always_matches() {
54      self.rules.to_css(dest)?;
55      return Ok(());
56    }
57
58    #[cfg(feature = "sourcemap")]
59    dest.add_mapping(self.loc);
60    dest.write_str("@media ")?;
61    self.query.to_css(dest)?;
62    dest.whitespace()?;
63    dest.write_char('{')?;
64    dest.indent();
65    dest.newline()?;
66    self.rules.to_css(dest)?;
67    dest.dedent();
68    dest.newline()?;
69    dest.write_char('}')
70  }
71}
lightningcss/rules/media.rs

lightningcss/rules/
media.rs
