servo/components/style/gecko/values.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

#![allow(unsafe_code)]

//! Different kind of helpers to interact with Gecko values.

use crate::counter_style::{Symbol, Symbols};
use crate::gecko_bindings::structs::CounterStylePtr;
use crate::values::generics::CounterStyle;
use crate::values::Either;
use crate::Atom;
use app_units::Au;
use cssparser::RGBA;
use nsstring::{nsACString, nsCStr};
use std::cmp::max;

/// Convert a given RGBA value to `nscolor`.
pub fn convert_rgba_to_nscolor(rgba: &RGBA) -> u32 {
    ((rgba.alpha as u32) << 24) |
        ((rgba.blue as u32) << 16) |
        ((rgba.green as u32) << 8) |
        (rgba.red as u32)
}

/// Convert a given `nscolor` to a Servo RGBA value.
pub fn convert_nscolor_to_rgba(color: u32) -> RGBA {
    RGBA::new(
        (color & 0xff) as u8,
        (color >> 8 & 0xff) as u8,
        (color >> 16 & 0xff) as u8,
        (color >> 24 & 0xff) as u8,
    )
}

/// Round `width` down to the nearest device pixel, but any non-zero value that
/// would round down to zero is clamped to 1 device pixel.  Used for storing
/// computed values of border-*-width and outline-width.
#[inline]
pub fn round_border_to_device_pixels(width: Au, au_per_device_px: Au) -> Au {
    if width == Au(0) {
        Au(0)
    } else {
        max(
            au_per_device_px,
            Au(width.0 / au_per_device_px.0 * au_per_device_px.0),
        )
    }
}

impl CounterStyle {
    /// Convert this counter style to a Gecko CounterStylePtr.
    pub fn to_gecko_value(self, gecko_value: &mut CounterStylePtr) {
        use crate::gecko_bindings::bindings::Gecko_SetCounterStyleToName as set_name;
        use crate::gecko_bindings::bindings::Gecko_SetCounterStyleToSymbols as set_symbols;
        match self {
            CounterStyle::Name(name) => unsafe {
                debug_assert_ne!(name.0, atom!("none"));
                set_name(gecko_value, name.0.into_addrefed());
            },
            CounterStyle::Symbols(symbols_type, symbols) => {
                let symbols: Vec<_> = symbols
                    .0
                    .iter()
                    .map(|symbol| match *symbol {
                        Symbol::String(ref s) => nsCStr::from(&**s),
                        Symbol::Ident(_) => unreachable!("Should not have identifier in symbols()"),
                    })
                    .collect();
                let symbols: Vec<_> = symbols
                    .iter()
                    .map(|symbol| symbol as &nsACString as *const _)
                    .collect();
                unsafe {
                    set_symbols(
                        gecko_value,
                        symbols_type.to_gecko_keyword(),
                        symbols.as_ptr(),
                        symbols.len() as u32,
                    )
                };
            },
        }
    }

    /// Convert Gecko CounterStylePtr to CounterStyle or String.
    pub fn from_gecko_value(gecko_value: &CounterStylePtr) -> Either<Self, String> {
        use crate::gecko_bindings::bindings;
        use crate::values::generics::SymbolsType;
        use crate::values::CustomIdent;

        let name = unsafe { bindings::Gecko_CounterStyle_GetName(gecko_value) };
        if !name.is_null() {
            let name = unsafe { Atom::from_raw(name) };
            debug_assert_ne!(name, atom!("none"));
            Either::First(CounterStyle::Name(CustomIdent(name)))
        } else {
            let anonymous =
                unsafe { bindings::Gecko_CounterStyle_GetAnonymous(gecko_value).as_ref() }.unwrap();
            let symbols = &anonymous.mSymbols;
            if anonymous.mSingleString {
                debug_assert_eq!(symbols.len(), 1);
                Either::Second(symbols[0].to_string())
            } else {
                let symbol_type = SymbolsType::from_gecko_keyword(anonymous.mSystem as u32);
                let symbols = symbols
                    .iter()
                    .map(|gecko_symbol| Symbol::String(gecko_symbol.to_string().into()))
                    .collect();
                Either::First(CounterStyle::Symbols(symbol_type, Symbols(symbols)))
            }
        }
    }
}