tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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align.rs (3259B)

      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 //! Values for CSS Box Alignment properties
      6 //!
      7 //! https://drafts.csswg.org/css-align/
      8 
      9 use crate::derives::*;
     10 use crate::values::computed::{Context, ToComputedValue};
     11 use crate::values::specified;
     12 
     13 pub use super::specified::{ContentDistribution, ItemPlacement, SelfAlignment};
     14 
     15 /// The computed value for the `justify-items` property.
     16 ///
     17 /// Need to carry around both the specified and computed value to handle the
     18 /// special legacy keyword without destroying style sharing.
     19 ///
     20 /// In particular, `justify-items` is a reset property, so we ought to be able
     21 /// to share its computed representation across elements as long as they match
     22 /// the same rules. Except that it's not true if the specified value for
     23 /// `justify-items` is `legacy` and the computed value of the parent has the
     24 /// `legacy` modifier.
     25 ///
     26 /// So instead of computing `legacy` "normally" looking at get_parent_position(),
     27 /// marking it as uncacheable, we carry the specified value around and handle
     28 /// the special case in `StyleAdjuster` instead, only when the result of the
     29 /// computation would vary.
     30 ///
     31 /// Note that we also need to special-case this property in matching.rs, in
     32 /// order to properly handle changes to the legacy keyword... This all kinda
     33 /// sucks :(.
     34 ///
     35 /// See the discussion in https://bugzil.la/1384542.
     36 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss, ToResolvedValue, ToTyped)]
     37 #[repr(C)]
     38 pub struct ComputedJustifyItems {
     39    /// The specified value for the property. Can contain the bare `legacy`
     40    /// keyword.
     41    #[css(skip)]
     42    pub specified: specified::JustifyItems,
     43    /// The computed value for the property. Cannot contain the bare `legacy`
     44    /// keyword, but note that it could contain it in combination with other
     45    /// keywords like `left`, `right` or `center`.
     46    pub computed: specified::JustifyItems,
     47 }
     48 
     49 pub use self::ComputedJustifyItems as JustifyItems;
     50 
     51 impl JustifyItems {
     52    /// Returns the `legacy` value.
     53    pub fn legacy() -> Self {
     54        Self {
     55            specified: specified::JustifyItems::legacy(),
     56            computed: specified::JustifyItems::normal(),
     57        }
     58    }
     59 }
     60 
     61 impl ToComputedValue for specified::JustifyItems {
     62    type ComputedValue = JustifyItems;
     63 
     64    /// <https://drafts.csswg.org/css-align/#valdef-justify-items-legacy>
     65    fn to_computed_value(&self, _context: &Context) -> JustifyItems {
     66        use crate::values::specified::align;
     67        let specified = *self;
     68        let computed = if (self.0).0 != align::AlignFlags::LEGACY {
     69            *self
     70        } else {
     71            // If the inherited value of `justify-items` includes the
     72            // `legacy` keyword, `legacy` computes to the inherited value, but
     73            // we assume it computes to `normal`, and handle that special-case
     74            // in StyleAdjuster.
     75            Self::normal()
     76        };
     77 
     78        JustifyItems {
     79            specified,
     80            computed,
     81        }
     82    }
     83 
     84    #[inline]
     85    fn from_computed_value(computed: &JustifyItems) -> Self {
     86        computed.specified
     87    }
     88 }