servo/components/style/values/specified/position.rs
Nicholas Nethercote 4506f0d30c Replace all uses of the heapsize crate with malloc_size_of.
Servo currently uses `heapsize`, but Stylo/Gecko use `malloc_size_of`.
`malloc_size_of` is better -- it handles various cases that `heapsize` does not
-- so this patch changes Servo to use `malloc_size_of`.

This patch makes the following changes to the `malloc_size_of` crate.

- Adds `MallocSizeOf` trait implementations for numerous types, some built-in
  (e.g. `VecDeque`), some external and Servo-only (e.g. `string_cache`).

- Makes `enclosing_size_of_op` optional, because vanilla jemalloc doesn't
  support that operation.

- For `HashSet`/`HashMap`, falls back to a computed estimate when
  `enclosing_size_of_op` isn't available.

- Adds an extern "C" `malloc_size_of` function that does the actual heap
  measurement; this is based on the same functions from the `heapsize` crate.

This patch makes the following changes elsewhere.

- Converts all the uses of `heapsize` to instead use `malloc_size_of`.

- Disables the "heapsize"/"heap_size" feature for the external crates that
  provide it.

- Removes the `HeapSizeOf` implementation from `hashglobe`.

- Adds `ignore` annotations to a few `Rc`/`Arc`, because `malloc_size_of`
  doesn't derive those types, unlike `heapsize`.
2017-10-18 22:20:37 +11:00

368 lines
14 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/. */
//! CSS handling for the specified value of
//! [`position`][position]s
//!
//! [position]: https://drafts.csswg.org/css-backgrounds-3/#position
use cssparser::Parser;
use parser::{Parse, ParserContext};
use std::fmt;
use style_traits::{ToCss, ParseError};
use values::computed::{CalcLengthOrPercentage, LengthOrPercentage as ComputedLengthOrPercentage};
use values::computed::{Context, Percentage, ToComputedValue};
use values::generics::position::Position as GenericPosition;
use values::specified::{AllowQuirks, LengthOrPercentage};
use values::specified::transform::OriginComponent;
/// The specified value of a CSS `<position>`
pub type Position = GenericPosition<HorizontalPosition, VerticalPosition>;
/// The specified value of a horizontal position.
pub type HorizontalPosition = PositionComponent<X>;
/// The specified value of a vertical position.
pub type VerticalPosition = PositionComponent<Y>;
/// The specified value of a component of a CSS `<position>`.
#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
pub enum PositionComponent<S> {
/// `center`
Center,
/// `<lop>`
Length(LengthOrPercentage),
/// `<side> <lop>?`
Side(S, Option<LengthOrPercentage>),
}
define_css_keyword_enum! { X:
"left" => Left,
"right" => Right,
}
add_impls_for_keyword_enum!(X);
define_css_keyword_enum! { Y:
"top" => Top,
"bottom" => Bottom,
}
add_impls_for_keyword_enum!(Y);
impl Parse for Position {
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
Self::parse_quirky(context, input, AllowQuirks::No)
}
}
impl Position {
/// Parses a `<position>`, with quirks.
pub fn parse_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
match input.try(|i| PositionComponent::parse_quirky(context, i, allow_quirks)) {
Ok(x_pos @ PositionComponent::Center) => {
if let Ok(y_pos) = input.try(|i|
PositionComponent::parse_quirky(context, i, allow_quirks)) {
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = input
.try(|i| PositionComponent::parse_quirky(context, i, allow_quirks))
.unwrap_or(x_pos);
let y_pos = PositionComponent::Center;
return Ok(Self::new(x_pos, y_pos));
},
Ok(PositionComponent::Side(x_keyword, lop)) => {
if input.try(|i| i.expect_ident_matching("center")).is_ok() {
let x_pos = PositionComponent::Side(x_keyword, lop);
let y_pos = PositionComponent::Center;
return Ok(Self::new(x_pos, y_pos));
}
if let Ok(y_keyword) = input.try(Y::parse) {
let y_lop = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)).ok();
let x_pos = PositionComponent::Side(x_keyword, lop);
let y_pos = PositionComponent::Side(y_keyword, y_lop);
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = PositionComponent::Side(x_keyword, None);
let y_pos = lop.map_or(PositionComponent::Center, PositionComponent::Length);
return Ok(Self::new(x_pos, y_pos));
},
Ok(x_pos @ PositionComponent::Length(_)) => {
if let Ok(y_keyword) = input.try(Y::parse) {
let y_pos = PositionComponent::Side(y_keyword, None);
return Ok(Self::new(x_pos, y_pos));
}
if let Ok(y_lop) = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)) {
let y_pos = PositionComponent::Length(y_lop);
return Ok(Self::new(x_pos, y_pos));
}
let y_pos = PositionComponent::Center;
let _ = input.try(|i| i.expect_ident_matching("center"));
return Ok(Self::new(x_pos, y_pos));
},
Err(_) => {},
}
let y_keyword = Y::parse(input)?;
let lop_and_x_pos: Result<_, ParseError> = input.try(|i| {
let y_lop = i.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)).ok();
if let Ok(x_keyword) = i.try(X::parse) {
let x_lop = i.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)).ok();
let x_pos = PositionComponent::Side(x_keyword, x_lop);
return Ok((y_lop, x_pos));
};
i.expect_ident_matching("center")?;
let x_pos = PositionComponent::Center;
Ok((y_lop, x_pos))
});
if let Ok((y_lop, x_pos)) = lop_and_x_pos {
let y_pos = PositionComponent::Side(y_keyword, y_lop);
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = PositionComponent::Center;
let y_pos = PositionComponent::Side(y_keyword, None);
Ok(Self::new(x_pos, y_pos))
}
/// `center center`
#[inline]
pub fn center() -> Self {
Self::new(PositionComponent::Center, PositionComponent::Center)
}
}
impl ToCss for Position {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
match (&self.horizontal, &self.vertical) {
(x_pos @ &PositionComponent::Side(_, Some(_)), &PositionComponent::Length(ref y_lop)) => {
x_pos.to_css(dest)?;
dest.write_str(" top ")?;
y_lop.to_css(dest)
},
(&PositionComponent::Length(ref x_lop), y_pos @ &PositionComponent::Side(_, Some(_))) => {
dest.write_str("left ")?;
x_lop.to_css(dest)?;
dest.write_str(" ")?;
y_pos.to_css(dest)
},
(x_pos, y_pos) => {
x_pos.to_css(dest)?;
dest.write_str(" ")?;
y_pos.to_css(dest)
},
}
}
}
impl<S: Parse> Parse for PositionComponent<S> {
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
Self::parse_quirky(context, input, AllowQuirks::No)
}
}
impl<S: Parse> PositionComponent<S> {
/// Parses a component of a CSS position, with quirks.
pub fn parse_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
if input.try(|i| i.expect_ident_matching("center")).is_ok() {
return Ok(PositionComponent::Center);
}
if let Ok(lop) = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)) {
return Ok(PositionComponent::Length(lop));
}
let keyword = S::parse(context, input)?;
let lop = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)).ok();
Ok(PositionComponent::Side(keyword, lop))
}
}
impl<S> PositionComponent<S> {
/// `0%`
pub fn zero() -> Self {
PositionComponent::Length(LengthOrPercentage::Percentage(Percentage::zero()))
}
}
impl<S: Side> ToComputedValue for PositionComponent<S> {
type ComputedValue = ComputedLengthOrPercentage;
fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
match *self {
PositionComponent::Center => {
ComputedLengthOrPercentage::Percentage(Percentage(0.5))
},
PositionComponent::Side(ref keyword, None) => {
let p = Percentage(if keyword.is_start() { 0. } else { 1. });
ComputedLengthOrPercentage::Percentage(p)
},
PositionComponent::Side(ref keyword, Some(ref length)) if !keyword.is_start() => {
match length.to_computed_value(context) {
ComputedLengthOrPercentage::Length(length) => {
ComputedLengthOrPercentage::Calc(
CalcLengthOrPercentage::new(-length, Some(Percentage::hundred())))
},
ComputedLengthOrPercentage::Percentage(p) => {
ComputedLengthOrPercentage::Percentage(Percentage(1.0 - p.0))
},
ComputedLengthOrPercentage::Calc(calc) => {
let p = Percentage(1. - calc.percentage.map_or(0., |p| p.0));
let l = -calc.unclamped_length();
ComputedLengthOrPercentage::Calc(CalcLengthOrPercentage::new(l, Some(p)))
},
}
},
PositionComponent::Side(_, Some(ref length)) |
PositionComponent::Length(ref length) => {
length.to_computed_value(context)
},
}
}
fn from_computed_value(computed: &Self::ComputedValue) -> Self {
PositionComponent::Length(ToComputedValue::from_computed_value(computed))
}
}
impl<S: Side> PositionComponent<S> {
/// The initial specified value of a position component, i.e. the start side.
pub fn initial_specified_value() -> Self {
PositionComponent::Side(S::start(), None)
}
}
/// Represents a side, either horizontal or vertical, of a CSS position.
pub trait Side {
/// Returns the start side.
fn start() -> Self;
/// Returns whether this side is the start side.
fn is_start(&self) -> bool;
}
impl Side for X {
#[inline]
fn start() -> Self {
X::Left
}
#[inline]
fn is_start(&self) -> bool {
*self == X::Left
}
}
impl Side for Y {
#[inline]
fn start() -> Self {
Y::Top
}
#[inline]
fn is_start(&self) -> bool {
*self == Y::Top
}
}
/// The specified value of a legacy CSS `<position>`
/// Modern position syntax supports 3 and 4-value syntax. That means:
/// If three or four values are given, then each <percentage> or <length> represents an offset
/// and must be preceded by a keyword, which specifies from which edge the offset is given.
/// For example, `bottom 10px right 20px` represents a `10px` vertical
/// offset up from the bottom edge and a `20px` horizontal offset leftward from the right edge.
/// If three values are given, the missing offset is assumed to be zero.
/// But for some historical reasons we need to keep CSS Level 2 syntax which only supports up to
/// 2-value. This type represents this 2-value syntax.
pub type LegacyPosition = GenericPosition<LegacyHPosition, LegacyVPosition>;
/// The specified value of a horizontal position.
pub type LegacyHPosition = OriginComponent<X>;
/// The specified value of a vertical position.
pub type LegacyVPosition = OriginComponent<Y>;
impl Parse for LegacyPosition {
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
Self::parse_quirky(context, input, AllowQuirks::No)
}
}
impl LegacyPosition {
/// Parses a `<position>`, with quirks.
pub fn parse_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
match input.try(|i| OriginComponent::parse(context, i)) {
Ok(x_pos @ OriginComponent::Center) => {
if let Ok(y_pos) = input.try(|i|
OriginComponent::parse(context, i)) {
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = input
.try(|i| OriginComponent::parse(context, i))
.unwrap_or(x_pos);
let y_pos = OriginComponent::Center;
return Ok(Self::new(x_pos, y_pos));
},
Ok(OriginComponent::Side(x_keyword)) => {
if let Ok(y_keyword) = input.try(Y::parse) {
let x_pos = OriginComponent::Side(x_keyword);
let y_pos = OriginComponent::Side(y_keyword);
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = OriginComponent::Side(x_keyword);
if let Ok(y_lop) = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)) {
return Ok(Self::new(x_pos, OriginComponent::Length(y_lop)))
}
let _ = input.try(|i| i.expect_ident_matching("center"));
return Ok(Self::new(x_pos, OriginComponent::Center));
},
Ok(x_pos @ OriginComponent::Length(_)) => {
if let Ok(y_keyword) = input.try(Y::parse) {
let y_pos = OriginComponent::Side(y_keyword);
return Ok(Self::new(x_pos, y_pos));
}
if let Ok(y_lop) = input.try(|i| LengthOrPercentage::parse_quirky(context, i, allow_quirks)) {
let y_pos = OriginComponent::Length(y_lop);
return Ok(Self::new(x_pos, y_pos));
}
let _ = input.try(|i| i.expect_ident_matching("center"));
return Ok(Self::new(x_pos, OriginComponent::Center));
},
Err(_) => {},
}
let y_keyword = Y::parse(input)?;
let x_pos: Result<_, ParseError> = input.try(|i| {
if let Ok(x_keyword) = i.try(X::parse) {
let x_pos = OriginComponent::Side(x_keyword);
return Ok(x_pos);
}
i.expect_ident_matching("center")?;
Ok(OriginComponent::Center)
});
if let Ok(x_pos) = x_pos {
let y_pos = OriginComponent::Side(y_keyword);
return Ok(Self::new(x_pos, y_pos));
}
let x_pos = OriginComponent::Center;
let y_pos = OriginComponent::Side(y_keyword);
Ok(Self::new(x_pos, y_pos))
}
/// `center center`
#[inline]
pub fn center() -> Self {
Self::new(OriginComponent::Center, OriginComponent::Center)
}
}
impl ToCss for LegacyPosition {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
self.horizontal.to_css(dest)?;
dest.write_str(" ")?;
self.vertical.to_css(dest)
}
}