servo/components/style/macros.rs

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
   4
   5 //! Various macro helpers.
   6
   7 macro_rules! exclusive_value {
   8     (($value:ident, $set:expr) => $ident:path) => {
   9         if $value.intersects($set) {
  10             return Err(());
  11         } else {
  12             $ident
  13         }
  14     };
  15 }
  16
  17 #[cfg(feature = "gecko")]
  18 macro_rules! impl_gecko_keyword_conversions {
  19     ($name:ident, $utype:ty) => {
  20         impl From<$utype> for $name {
  21             fn from(bits: $utype) -> $name {
  22                 $name::from_gecko_keyword(bits)
  23             }
  24         }
  25
  26         impl From<$name> for $utype {
  27             fn from(v: $name) -> $utype {
  28                 v.to_gecko_keyword()
  29             }
  30         }
  31     };
  32 }
  33
  34 macro_rules! trivial_to_computed_value {
  35     ($name:ty) => {
  36         impl $crate::values::computed::ToComputedValue for $name {
  37             type ComputedValue = $name;
  38
  39             fn to_computed_value(&self, _: &$crate::values::computed::Context) -> Self {
  40                 self.clone()
  41             }
  42
  43             fn from_computed_value(other: &Self) -> Self {
  44                 other.clone()
  45             }
  46         }
  47     };
  48 }
  49
  50 /// A macro to parse an identifier, or return an `UnexpectedIdent` error
  51 /// otherwise.
  52 ///
  53 /// FIXME(emilio): The fact that `UnexpectedIdent` is a `SelectorParseError`
  54 /// doesn't make a lot of sense to me.
  55 macro_rules! try_match_ident_ignore_ascii_case {
  56     ($input:expr, $( $match_body:tt )*) => {{
  57         let location = $input.current_source_location();
  58         let ident = $input.expect_ident_cloned()?;
  59         match_ignore_ascii_case! { &ident,
  60             $( $match_body )*
  61             _ => return Err(location.new_custom_error(
  62                 ::selectors::parser::SelectorParseErrorKind::UnexpectedIdent(ident.clone())
  63             ))
  64         }
  65     }}
  66 }
  67
  68 macro_rules! define_keyword_type {
  69     ($name:ident, $css:expr) => {
  70         #[allow(missing_docs)]
  71         #[derive(
  72             Animate,
  73             Clone,
  74             ComputeSquaredDistance,
  75             Copy,
  76             MallocSizeOf,
  77             PartialEq,
  78             SpecifiedValueInfo,
  79             ToAnimatedValue,
  80             ToAnimatedZero,
  81             ToComputedValue,
  82             ToCss,
  83             ToResolvedValue,
  84             ToShmem,
  85         )]
  86         pub struct $name;
  87
  88         impl fmt::Debug for $name {
  89             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  90                 f.write_str($css)
  91             }
  92         }
  93
  94         impl $crate::parser::Parse for $name {
  95             fn parse<'i, 't>(
  96                 _context: &$crate::parser::ParserContext,
  97                 input: &mut ::cssparser::Parser<'i, 't>,
  98             ) -> Result<$name, ::style_traits::ParseError<'i>> {
  99                 input
 100                     .expect_ident_matching($css)
 101                     .map(|_| $name)
 102                     .map_err(|e| e.into())
 103             }
 104         }
 105     };
 106 }
 107
 108 #[cfg(feature = "servo")]
 109 macro_rules! local_name {
 110     ($s:tt) => {
 111         $crate::values::GenericAtomIdent(html5ever::local_name!($s))
 112     };
 113 }
 114
 115 #[cfg(feature = "servo")]
 116 macro_rules! ns {
 117     () => {
 118         $crate::values::GenericAtomIdent(html5ever::ns!())
 119     };
 120     ($s:tt) => {
 121         $crate::values::GenericAtomIdent(html5ever::ns!($s))
 122     };
 123 }
 124
 125 #[cfg(feature = "gecko")]
 126 macro_rules! local_name {
 127     ($s:tt) => {
 128         $crate::values::AtomIdent(atom!($s))
 129     };
 130 }