mirror of
https://github.com/servo/servo.git
synced 2025-10-12 22:40:19 +01:00
6fefe522a3
Right now when calling getComputedStyle with an element from another document, we return the style using the pres context of that document, not of the document of the window getComputedStyle was called on, so this holds. But it will stop holding if we ever change this, so assert it doesn't happen. Bug: 1374062 Reviewed-By: Manishearth MozReview-Commit-ID: 3g8yQWWdsen
700 lines
26 KiB
Rust
700 lines
26 KiB
Rust
/* 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 http://mozilla.org/MPL/2.0/. */
|
|
|
|
//! Gecko's media-query device and expression representation.
|
|
|
|
use app_units::Au;
|
|
use context::QuirksMode;
|
|
use cssparser::{CssStringWriter, Parser, RGBA, Token, BasicParseError};
|
|
use euclid::Size2D;
|
|
use font_metrics::get_metrics_provider_for_product;
|
|
use gecko::values::convert_nscolor_to_rgba;
|
|
use gecko_bindings::bindings;
|
|
use gecko_bindings::structs::{nsCSSKeyword, nsCSSProps_KTableEntry, nsCSSValue, nsCSSUnit, nsStringBuffer};
|
|
use gecko_bindings::structs::{nsMediaExpression_Range, nsMediaFeature};
|
|
use gecko_bindings::structs::{nsMediaFeature_ValueType, nsMediaFeature_RangeType, nsMediaFeature_RequirementFlags};
|
|
use gecko_bindings::structs::{nsPresContext, RawGeckoPresContextOwned};
|
|
use media_queries::MediaType;
|
|
use parser::ParserContext;
|
|
use properties::{ComputedValues, StyleBuilder};
|
|
use properties::longhands::font_size;
|
|
use selectors::parser::SelectorParseError;
|
|
use std::fmt::{self, Write};
|
|
use std::sync::atomic::{AtomicBool, AtomicIsize, Ordering};
|
|
use str::starts_with_ignore_ascii_case;
|
|
use string_cache::Atom;
|
|
use style_traits::{ToCss, ParseError, StyleParseError};
|
|
use style_traits::viewport::ViewportConstraints;
|
|
use stylearc::Arc;
|
|
use values::{CSSFloat, specified};
|
|
use values::computed::{self, ToComputedValue};
|
|
|
|
/// The `Device` in Gecko wraps a pres context, has a default values computed,
|
|
/// and contains all the viewport rule state.
|
|
pub struct Device {
|
|
/// NB: The pres context lifetime is tied to the styleset, who owns the
|
|
/// stylist, and thus the `Device`, so having a raw pres context pointer
|
|
/// here is fine.
|
|
pres_context: RawGeckoPresContextOwned,
|
|
default_values: Arc<ComputedValues>,
|
|
viewport_override: Option<ViewportConstraints>,
|
|
/// The font size of the root element
|
|
/// This is set when computing the style of the root
|
|
/// element, and used for rem units in other elements.
|
|
///
|
|
/// When computing the style of the root element, there can't be any
|
|
/// other style being computed at the same time, given we need the style of
|
|
/// the parent to compute everything else. So it is correct to just use
|
|
/// a relaxed atomic here.
|
|
root_font_size: AtomicIsize,
|
|
/// Whether any styles computed in the document relied on the root font-size
|
|
/// by using rem units.
|
|
used_root_font_size: AtomicBool,
|
|
}
|
|
|
|
unsafe impl Sync for Device {}
|
|
unsafe impl Send for Device {}
|
|
|
|
impl Device {
|
|
/// Trivially constructs a new `Device`.
|
|
pub fn new(pres_context: RawGeckoPresContextOwned) -> Self {
|
|
assert!(!pres_context.is_null());
|
|
Device {
|
|
pres_context: pres_context,
|
|
default_values: ComputedValues::default_values(unsafe { &*pres_context }),
|
|
viewport_override: None,
|
|
root_font_size: AtomicIsize::new(font_size::get_initial_value().0 as isize), // FIXME(bz): Seems dubious?
|
|
used_root_font_size: AtomicBool::new(false),
|
|
}
|
|
}
|
|
|
|
/// Tells the device that a new viewport rule has been found, and stores the
|
|
/// relevant viewport constraints.
|
|
pub fn account_for_viewport_rule(&mut self,
|
|
constraints: &ViewportConstraints) {
|
|
self.viewport_override = Some(constraints.clone());
|
|
}
|
|
|
|
/// Returns the default computed values as a reference, in order to match
|
|
/// Servo.
|
|
pub fn default_computed_values(&self) -> &ComputedValues {
|
|
&*self.default_values
|
|
}
|
|
|
|
/// Returns the default computed values, but wrapped in an arc for cheap
|
|
/// cloning.
|
|
pub fn default_computed_values_arc(&self) -> &Arc<ComputedValues> {
|
|
&self.default_values
|
|
}
|
|
|
|
/// Returns the default computed values as an `Arc`, in order to avoid
|
|
/// clones.
|
|
pub fn default_values_arc(&self) -> &Arc<ComputedValues> {
|
|
&self.default_values
|
|
}
|
|
|
|
/// Get the font size of the root element (for rem)
|
|
pub fn root_font_size(&self) -> Au {
|
|
self.used_root_font_size.store(true, Ordering::Relaxed);
|
|
Au::new(self.root_font_size.load(Ordering::Relaxed) as i32)
|
|
}
|
|
|
|
/// Set the font size of the root element (for rem)
|
|
pub fn set_root_font_size(&self, size: Au) {
|
|
self.root_font_size.store(size.0 as isize, Ordering::Relaxed)
|
|
}
|
|
|
|
/// Gets the pres context associated with this document.
|
|
pub fn pres_context(&self) -> &nsPresContext {
|
|
unsafe { &*self.pres_context }
|
|
}
|
|
|
|
/// Recreates the default computed values.
|
|
pub fn reset_computed_values(&mut self) {
|
|
// NB: A following stylesheet flush will populate this if appropriate.
|
|
self.viewport_override = None;
|
|
self.default_values = ComputedValues::default_values(self.pres_context());
|
|
self.used_root_font_size.store(false, Ordering::Relaxed);
|
|
}
|
|
|
|
/// Returns whether we ever looked up the root font size of the Device.
|
|
pub fn used_root_font_size(&self) -> bool {
|
|
self.used_root_font_size.load(Ordering::Relaxed)
|
|
}
|
|
|
|
/// Recreates all the temporary state that the `Device` stores.
|
|
///
|
|
/// This includes the viewport override from `@viewport` rules, and also the
|
|
/// default computed values.
|
|
pub fn reset(&mut self) {
|
|
// NB: A following stylesheet flush will populate this if appropriate.
|
|
self.viewport_override = None;
|
|
self.reset_computed_values();
|
|
}
|
|
|
|
/// Returns the current media type of the device.
|
|
pub fn media_type(&self) -> MediaType {
|
|
unsafe {
|
|
// FIXME(emilio): Gecko allows emulating random media with
|
|
// mIsEmulatingMedia / mMediaEmulated . Refactor both sides so that
|
|
// is supported (probably just making MediaType an Atom).
|
|
if self.pres_context().mMedium == atom!("screen").as_ptr() {
|
|
MediaType::Screen
|
|
} else {
|
|
debug_assert!(self.pres_context().mMedium == atom!("print").as_ptr());
|
|
MediaType::Print
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Returns the current viewport size in app units.
|
|
pub fn au_viewport_size(&self) -> Size2D<Au> {
|
|
self.viewport_override.as_ref().map(|v| {
|
|
Size2D::new(Au::from_f32_px(v.size.width),
|
|
Au::from_f32_px(v.size.height))
|
|
}).unwrap_or_else(|| unsafe {
|
|
// TODO(emilio): Need to take into account scrollbars.
|
|
let area = &self.pres_context().mVisibleArea;
|
|
Size2D::new(Au(area.width), Au(area.height))
|
|
})
|
|
}
|
|
|
|
/// Returns whether document colors are enabled.
|
|
pub fn use_document_colors(&self) -> bool {
|
|
self.pres_context().mUseDocumentColors() != 0
|
|
}
|
|
|
|
/// Returns the default background color.
|
|
pub fn default_background_color(&self) -> RGBA {
|
|
convert_nscolor_to_rgba(self.pres_context().mBackgroundColor)
|
|
}
|
|
}
|
|
|
|
/// A expression for gecko contains a reference to the media feature, the value
|
|
/// the media query contained, and the range to evaluate.
|
|
#[derive(Debug, Clone)]
|
|
pub struct Expression {
|
|
feature: &'static nsMediaFeature,
|
|
value: Option<MediaExpressionValue>,
|
|
range: nsMediaExpression_Range
|
|
}
|
|
|
|
impl ToCss for Expression {
|
|
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
|
|
where W: fmt::Write,
|
|
{
|
|
dest.write_str("(")?;
|
|
|
|
if (self.feature.mReqFlags & nsMediaFeature_RequirementFlags::eHasWebkitPrefix as u8) != 0 {
|
|
dest.write_str("-webkit-")?;
|
|
}
|
|
match self.range {
|
|
nsMediaExpression_Range::eMin => dest.write_str("min-")?,
|
|
nsMediaExpression_Range::eMax => dest.write_str("max-")?,
|
|
nsMediaExpression_Range::eEqual => {},
|
|
}
|
|
|
|
// NB: CssStringWriter not needed, feature names are under control.
|
|
write!(dest, "{}", Atom::from(unsafe { *self.feature.mName }))?;
|
|
|
|
if let Some(ref val) = self.value {
|
|
dest.write_str(": ")?;
|
|
val.to_css(dest, self)?;
|
|
}
|
|
|
|
dest.write_str(")")
|
|
}
|
|
}
|
|
|
|
impl PartialEq for Expression {
|
|
fn eq(&self, other: &Expression) -> bool {
|
|
self.feature.mName == other.feature.mName &&
|
|
self.value == other.value && self.range == other.range
|
|
}
|
|
}
|
|
|
|
/// A resolution.
|
|
#[derive(PartialEq, Debug, Clone)]
|
|
pub enum Resolution {
|
|
/// Dots per inch.
|
|
Dpi(CSSFloat),
|
|
/// Dots per pixel.
|
|
Dppx(CSSFloat),
|
|
/// Dots per centimeter.
|
|
Dpcm(CSSFloat),
|
|
}
|
|
|
|
impl Resolution {
|
|
fn to_dpi(&self) -> CSSFloat {
|
|
match *self {
|
|
Resolution::Dpi(f) => f,
|
|
Resolution::Dppx(f) => f * 96.0,
|
|
Resolution::Dpcm(f) => f * 2.54,
|
|
}
|
|
}
|
|
|
|
fn parse<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
|
|
let (value, unit) = match input.next()? {
|
|
Token::Dimension { value, unit, .. } => {
|
|
(value, unit)
|
|
},
|
|
t => return Err(BasicParseError::UnexpectedToken(t).into()),
|
|
};
|
|
|
|
if value <= 0. {
|
|
return Err(StyleParseError::UnspecifiedError.into())
|
|
}
|
|
|
|
(match_ignore_ascii_case! { &unit,
|
|
"dpi" => Ok(Resolution::Dpi(value)),
|
|
"dppx" => Ok(Resolution::Dppx(value)),
|
|
"dpcm" => Ok(Resolution::Dpcm(value)),
|
|
_ => Err(())
|
|
}).map_err(|()| StyleParseError::UnexpectedDimension(unit).into())
|
|
}
|
|
}
|
|
|
|
impl ToCss for Resolution {
|
|
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
|
|
where W: fmt::Write,
|
|
{
|
|
match *self {
|
|
Resolution::Dpi(v) => write!(dest, "{}dpi", v),
|
|
Resolution::Dppx(v) => write!(dest, "{}dppx", v),
|
|
Resolution::Dpcm(v) => write!(dest, "{}dpcm", v),
|
|
}
|
|
}
|
|
}
|
|
|
|
unsafe fn string_from_ns_string_buffer(buffer: *const nsStringBuffer) -> String {
|
|
use std::slice;
|
|
debug_assert!(!buffer.is_null());
|
|
let data = buffer.offset(1) as *const u16;
|
|
let mut length = 0;
|
|
let mut iter = data;
|
|
while *iter != 0 {
|
|
length += 1;
|
|
iter = iter.offset(1);
|
|
}
|
|
String::from_utf16_lossy(slice::from_raw_parts(data, length))
|
|
}
|
|
|
|
/// A value found or expected in a media expression.
|
|
#[derive(PartialEq, Debug, Clone)]
|
|
pub enum MediaExpressionValue {
|
|
/// A length.
|
|
Length(specified::Length),
|
|
/// A (non-negative) integer.
|
|
Integer(u32),
|
|
/// A floating point value.
|
|
Float(CSSFloat),
|
|
/// A boolean value, specified as an integer (i.e., either 0 or 1).
|
|
BoolInteger(bool),
|
|
/// Two integers separated by '/', with optional whitespace on either side
|
|
/// of the '/'.
|
|
IntRatio(u32, u32),
|
|
/// A resolution.
|
|
Resolution(Resolution),
|
|
/// An enumerated value, defined by the variant keyword table in the
|
|
/// feature's `mData` member.
|
|
Enumerated(i16),
|
|
/// An identifier.
|
|
///
|
|
/// TODO(emilio): Maybe atomize?
|
|
Ident(String),
|
|
}
|
|
|
|
impl MediaExpressionValue {
|
|
fn from_css_value(for_expr: &Expression, css_value: &nsCSSValue) -> Option<Self> {
|
|
// NB: If there's a null value, that means that we don't support the
|
|
// feature.
|
|
if css_value.mUnit == nsCSSUnit::eCSSUnit_Null {
|
|
return None;
|
|
}
|
|
|
|
match for_expr.feature.mValueType {
|
|
nsMediaFeature_ValueType::eLength => {
|
|
debug_assert!(css_value.mUnit == nsCSSUnit::eCSSUnit_Pixel);
|
|
let pixels = css_value.float_unchecked();
|
|
Some(MediaExpressionValue::Length(specified::Length::from_px(pixels)))
|
|
}
|
|
nsMediaFeature_ValueType::eInteger => {
|
|
let i = css_value.integer_unchecked();
|
|
debug_assert!(i >= 0);
|
|
Some(MediaExpressionValue::Integer(i as u32))
|
|
}
|
|
nsMediaFeature_ValueType::eFloat => {
|
|
debug_assert!(css_value.mUnit == nsCSSUnit::eCSSUnit_Number);
|
|
Some(MediaExpressionValue::Float(css_value.float_unchecked()))
|
|
}
|
|
nsMediaFeature_ValueType::eBoolInteger => {
|
|
debug_assert!(css_value.mUnit == nsCSSUnit::eCSSUnit_Integer);
|
|
let i = css_value.integer_unchecked();
|
|
debug_assert!(i == 0 || i == 1);
|
|
Some(MediaExpressionValue::BoolInteger(i == 1))
|
|
}
|
|
nsMediaFeature_ValueType::eResolution => {
|
|
debug_assert!(css_value.mUnit == nsCSSUnit::eCSSUnit_Inch);
|
|
Some(MediaExpressionValue::Resolution(Resolution::Dpi(css_value.float_unchecked())))
|
|
}
|
|
nsMediaFeature_ValueType::eEnumerated => {
|
|
let value = css_value.integer_unchecked() as i16;
|
|
Some(MediaExpressionValue::Enumerated(value))
|
|
}
|
|
nsMediaFeature_ValueType::eIdent => {
|
|
debug_assert!(css_value.mUnit == nsCSSUnit::eCSSUnit_Ident);
|
|
let string = unsafe {
|
|
string_from_ns_string_buffer(*css_value.mValue.mString.as_ref())
|
|
};
|
|
Some(MediaExpressionValue::Ident(string))
|
|
}
|
|
nsMediaFeature_ValueType::eIntRatio => {
|
|
let array = unsafe { css_value.array_unchecked() };
|
|
debug_assert_eq!(array.len(), 2);
|
|
let first = array[0].integer_unchecked();
|
|
let second = array[1].integer_unchecked();
|
|
|
|
debug_assert!(first >= 0 && second >= 0);
|
|
Some(MediaExpressionValue::IntRatio(first as u32, second as u32))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl MediaExpressionValue {
|
|
fn to_css<W>(&self, dest: &mut W, for_expr: &Expression) -> fmt::Result
|
|
where W: fmt::Write,
|
|
{
|
|
match *self {
|
|
MediaExpressionValue::Length(ref l) => l.to_css(dest),
|
|
MediaExpressionValue::Integer(v) => write!(dest, "{}", v),
|
|
MediaExpressionValue::Float(v) => write!(dest, "{}", v),
|
|
MediaExpressionValue::BoolInteger(v) => {
|
|
dest.write_str(if v { "1" } else { "0" })
|
|
},
|
|
MediaExpressionValue::IntRatio(a, b) => {
|
|
write!(dest, "{}/{}", a, b)
|
|
},
|
|
MediaExpressionValue::Resolution(ref r) => r.to_css(dest),
|
|
MediaExpressionValue::Ident(ref ident) => {
|
|
CssStringWriter::new(dest).write_str(ident)
|
|
}
|
|
MediaExpressionValue::Enumerated(value) => unsafe {
|
|
use std::{slice, str};
|
|
use std::os::raw::c_char;
|
|
|
|
// NB: All the keywords on nsMediaFeatures are static,
|
|
// well-formed utf-8.
|
|
let mut length = 0;
|
|
|
|
let (keyword, _value) =
|
|
find_in_table(*for_expr.feature.mData.mKeywordTable.as_ref(),
|
|
|_kw, val| val == value)
|
|
.expect("Value not found in the keyword table?");
|
|
|
|
let buffer: *const c_char =
|
|
bindings::Gecko_CSSKeywordString(keyword, &mut length);
|
|
let buffer =
|
|
slice::from_raw_parts(buffer as *const u8, length as usize);
|
|
|
|
let string = str::from_utf8_unchecked(buffer);
|
|
|
|
dest.write_str(string)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn find_feature<F>(mut f: F) -> Option<&'static nsMediaFeature>
|
|
where F: FnMut(&'static nsMediaFeature) -> bool,
|
|
{
|
|
// FIXME(emilio): With build-time bindgen, we would be able to use
|
|
// structs::nsMediaFeatures_features. That would unfortunately break MSVC
|
|
// builds, or require one bindings file per platform.
|
|
//
|
|
// I'm not into any of those, so meanwhile let's use a FFI function.
|
|
unsafe {
|
|
let mut features = bindings::Gecko_GetMediaFeatures();
|
|
while !(*features).mName.is_null() {
|
|
if f(&*features) {
|
|
return Some(&*features);
|
|
}
|
|
features = features.offset(1);
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
unsafe fn find_in_table<F>(mut current_entry: *const nsCSSProps_KTableEntry,
|
|
mut f: F)
|
|
-> Option<(nsCSSKeyword, i16)>
|
|
where F: FnMut(nsCSSKeyword, i16) -> bool
|
|
{
|
|
loop {
|
|
let value = (*current_entry).mValue;
|
|
let keyword = (*current_entry).mKeyword;
|
|
|
|
if value == -1 {
|
|
return None; // End of the table.
|
|
}
|
|
|
|
if f(keyword, value) {
|
|
return Some((keyword, value));
|
|
}
|
|
|
|
current_entry = current_entry.offset(1);
|
|
}
|
|
}
|
|
|
|
impl Expression {
|
|
/// Trivially construct a new expression.
|
|
fn new(feature: &'static nsMediaFeature,
|
|
value: Option<MediaExpressionValue>,
|
|
range: nsMediaExpression_Range) -> Self {
|
|
Expression {
|
|
feature: feature,
|
|
value: value,
|
|
range: range,
|
|
}
|
|
}
|
|
|
|
/// Parse a media expression of the form:
|
|
///
|
|
/// ```
|
|
/// (media-feature: media-value)
|
|
/// ```
|
|
pub fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
|
|
-> Result<Self, ParseError<'i>> {
|
|
input.expect_parenthesis_block()?;
|
|
input.parse_nested_block(|input| {
|
|
let ident = input.expect_ident()?;
|
|
|
|
let mut flags = 0;
|
|
let result = {
|
|
let mut feature_name = &*ident;
|
|
|
|
// TODO(emilio): this is under a pref in Gecko.
|
|
if starts_with_ignore_ascii_case(feature_name, "-webkit-") {
|
|
feature_name = &feature_name[8..];
|
|
flags |= nsMediaFeature_RequirementFlags::eHasWebkitPrefix as u8;
|
|
}
|
|
|
|
let range = if starts_with_ignore_ascii_case(feature_name, "min-") {
|
|
feature_name = &feature_name[4..];
|
|
nsMediaExpression_Range::eMin
|
|
} else if starts_with_ignore_ascii_case(feature_name, "max-") {
|
|
feature_name = &feature_name[4..];
|
|
nsMediaExpression_Range::eMax
|
|
} else {
|
|
nsMediaExpression_Range::eEqual
|
|
};
|
|
|
|
let atom = Atom::from(feature_name);
|
|
match find_feature(|f| atom.as_ptr() == unsafe { *f.mName }) {
|
|
Some(f) => Ok((f, range)),
|
|
None => Err(()),
|
|
}
|
|
};
|
|
|
|
let (feature, range) = match result {
|
|
Ok((feature, range)) => (feature, range),
|
|
Err(()) => return Err(SelectorParseError::UnexpectedIdent(ident).into()),
|
|
};
|
|
|
|
if (feature.mReqFlags & !flags) != 0 {
|
|
return Err(SelectorParseError::UnexpectedIdent(ident).into());
|
|
}
|
|
|
|
if range != nsMediaExpression_Range::eEqual &&
|
|
feature.mRangeType != nsMediaFeature_RangeType::eMinMaxAllowed {
|
|
return Err(SelectorParseError::UnexpectedIdent(ident).into());
|
|
}
|
|
|
|
// If there's no colon, this is a media query of the form
|
|
// '(<feature>)', that is, there's no value specified.
|
|
//
|
|
// Gecko doesn't allow ranged expressions without a value, so just
|
|
// reject them here too.
|
|
if input.try(|i| i.expect_colon()).is_err() {
|
|
if range != nsMediaExpression_Range::eEqual {
|
|
return Err(StyleParseError::RangedExpressionWithNoValue.into())
|
|
}
|
|
return Ok(Expression::new(feature, None, range));
|
|
}
|
|
|
|
let value = match feature.mValueType {
|
|
nsMediaFeature_ValueType::eLength => {
|
|
MediaExpressionValue::Length(
|
|
specified::Length::parse_non_negative(context, input)?)
|
|
},
|
|
nsMediaFeature_ValueType::eInteger => {
|
|
let i = input.expect_integer()?;
|
|
if i < 0 {
|
|
return Err(StyleParseError::UnspecifiedError.into())
|
|
}
|
|
MediaExpressionValue::Integer(i as u32)
|
|
}
|
|
nsMediaFeature_ValueType::eBoolInteger => {
|
|
let i = input.expect_integer()?;
|
|
if i < 0 || i > 1 {
|
|
return Err(StyleParseError::UnspecifiedError.into())
|
|
}
|
|
MediaExpressionValue::BoolInteger(i == 1)
|
|
}
|
|
nsMediaFeature_ValueType::eFloat => {
|
|
MediaExpressionValue::Float(input.expect_number()?)
|
|
}
|
|
nsMediaFeature_ValueType::eIntRatio => {
|
|
let a = input.expect_integer()?;
|
|
if a <= 0 {
|
|
return Err(StyleParseError::UnspecifiedError.into())
|
|
}
|
|
|
|
input.expect_delim('/')?;
|
|
|
|
let b = input.expect_integer()?;
|
|
if b <= 0 {
|
|
return Err(StyleParseError::UnspecifiedError.into())
|
|
}
|
|
MediaExpressionValue::IntRatio(a as u32, b as u32)
|
|
}
|
|
nsMediaFeature_ValueType::eResolution => {
|
|
MediaExpressionValue::Resolution(Resolution::parse(input)?)
|
|
}
|
|
nsMediaFeature_ValueType::eEnumerated => {
|
|
let keyword = input.expect_ident()?;
|
|
let keyword = unsafe {
|
|
bindings::Gecko_LookupCSSKeyword(keyword.as_bytes().as_ptr(),
|
|
keyword.len() as u32)
|
|
};
|
|
|
|
let first_table_entry: *const nsCSSProps_KTableEntry = unsafe {
|
|
*feature.mData.mKeywordTable.as_ref()
|
|
};
|
|
|
|
let value =
|
|
match unsafe { find_in_table(first_table_entry, |kw, _| kw == keyword) } {
|
|
Some((_kw, value)) => {
|
|
value
|
|
}
|
|
None => return Err(StyleParseError::UnspecifiedError.into()),
|
|
};
|
|
|
|
MediaExpressionValue::Enumerated(value)
|
|
}
|
|
nsMediaFeature_ValueType::eIdent => {
|
|
MediaExpressionValue::Ident(input.expect_ident()?.into_owned())
|
|
}
|
|
};
|
|
|
|
Ok(Expression::new(feature, Some(value), range))
|
|
})
|
|
}
|
|
|
|
/// Returns whether this media query evaluates to true for the given device.
|
|
pub fn matches(&self, device: &Device, quirks_mode: QuirksMode) -> bool {
|
|
let mut css_value = nsCSSValue::null();
|
|
unsafe {
|
|
(self.feature.mGetter.unwrap())(device.pres_context,
|
|
self.feature,
|
|
&mut css_value)
|
|
};
|
|
|
|
let value = match MediaExpressionValue::from_css_value(self, &css_value) {
|
|
Some(v) => v,
|
|
None => return false,
|
|
};
|
|
|
|
self.evaluate_against(device, &value, quirks_mode)
|
|
}
|
|
|
|
fn evaluate_against(&self,
|
|
device: &Device,
|
|
actual_value: &MediaExpressionValue,
|
|
quirks_mode: QuirksMode)
|
|
-> bool {
|
|
use self::MediaExpressionValue::*;
|
|
use std::cmp::Ordering;
|
|
|
|
debug_assert!(self.range == nsMediaExpression_Range::eEqual ||
|
|
self.feature.mRangeType == nsMediaFeature_RangeType::eMinMaxAllowed,
|
|
"Whoops, wrong range");
|
|
|
|
let default_values = device.default_computed_values();
|
|
|
|
|
|
let provider = get_metrics_provider_for_product();
|
|
|
|
// http://dev.w3.org/csswg/mediaqueries3/#units
|
|
// em units are relative to the initial font-size.
|
|
let context = computed::Context {
|
|
is_root_element: false,
|
|
device: device,
|
|
inherited_style: default_values,
|
|
layout_parent_style: default_values,
|
|
style: StyleBuilder::for_derived_style(default_values),
|
|
font_metrics_provider: &provider,
|
|
cached_system_font: None,
|
|
in_media_query: true,
|
|
// TODO: pass the correct value here.
|
|
quirks_mode: quirks_mode,
|
|
};
|
|
|
|
let required_value = match self.value {
|
|
Some(ref v) => v,
|
|
None => {
|
|
// If there's no value, always match unless it's a zero length
|
|
// or a zero integer or boolean.
|
|
return match *actual_value {
|
|
BoolInteger(v) => v,
|
|
Integer(v) => v != 0,
|
|
Length(ref l) => l.to_computed_value(&context) != Au(0),
|
|
_ => true,
|
|
}
|
|
}
|
|
};
|
|
|
|
// FIXME(emilio): Handle the possible floating point errors?
|
|
let cmp = match (required_value, actual_value) {
|
|
(&Length(ref one), &Length(ref other)) => {
|
|
one.to_computed_value(&context)
|
|
.cmp(&other.to_computed_value(&context))
|
|
}
|
|
(&Integer(one), &Integer(ref other)) => one.cmp(other),
|
|
(&BoolInteger(one), &BoolInteger(ref other)) => one.cmp(other),
|
|
(&Float(one), &Float(ref other)) => one.partial_cmp(other).unwrap(),
|
|
(&IntRatio(one_num, one_den), &IntRatio(other_num, other_den)) => {
|
|
(one_num * other_den).partial_cmp(&(other_num * one_den)).unwrap()
|
|
}
|
|
(&Resolution(ref one), &Resolution(ref other)) => {
|
|
let actual_dpi = unsafe {
|
|
if (*device.pres_context).mOverrideDPPX > 0.0 {
|
|
self::Resolution::Dppx((*device.pres_context).mOverrideDPPX)
|
|
.to_dpi()
|
|
} else {
|
|
other.to_dpi()
|
|
}
|
|
};
|
|
|
|
one.to_dpi().partial_cmp(&actual_dpi).unwrap()
|
|
}
|
|
(&Ident(ref one), &Ident(ref other)) => {
|
|
debug_assert!(self.feature.mRangeType != nsMediaFeature_RangeType::eMinMaxAllowed);
|
|
return one == other;
|
|
}
|
|
(&Enumerated(one), &Enumerated(other)) => {
|
|
debug_assert!(self.feature.mRangeType != nsMediaFeature_RangeType::eMinMaxAllowed);
|
|
return one == other;
|
|
}
|
|
_ => unreachable!(),
|
|
};
|
|
|
|
cmp == Ordering::Equal || match self.range {
|
|
nsMediaExpression_Range::eMin => cmp == Ordering::Less,
|
|
nsMediaExpression_Range::eEqual => false,
|
|
nsMediaExpression_Range::eMax => cmp == Ordering::Greater,
|
|
}
|
|
}
|
|
}
|