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/* 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/. */
//! Specified types for CSS Easing functions.
use crate::parser::{Parse, ParserContext};
use crate::piecewise_linear::{PiecewiseLinearFunction, PiecewiseLinearFunctionBuilder};
use crate::values::computed::easing::TimingFunction as ComputedTimingFunction;
use crate::values::computed::{Context, ToComputedValue};
use crate::values::generics::easing::TimingFunction as GenericTimingFunction;
use crate::values::generics::easing::{StepPosition, TimingKeyword};
use crate::values::specified::{Integer, Number, Percentage};
use cssparser::{Delimiter, Parser, Token};
use selectors::parser::SelectorParseErrorKind;
use style_traits::{ParseError, StyleParseErrorKind};
/// A specified timing function.
pub type TimingFunction = GenericTimingFunction<Integer, Number, PiecewiseLinearFunction>;
impl Parse for TimingFunction {
fn parse<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
if let Ok(keyword) = input.try_parse(TimingKeyword::parse) {
return Ok(GenericTimingFunction::Keyword(keyword));
}
if let Ok(ident) = input.try_parse(|i| i.expect_ident_cloned()) {
let position = match_ignore_ascii_case! { &ident,
"step-start" => StepPosition::Start,
"step-end" => StepPosition::End,
_ => {
return Err(input.new_custom_error(
SelectorParseErrorKind::UnexpectedIdent(ident.clone())
));
},
};
return Ok(GenericTimingFunction::Steps(Integer::new(1), position));
}
let location = input.current_source_location();
let function = input.expect_function()?.clone();
input.parse_nested_block(move |i| {
match_ignore_ascii_case! { &function,
"cubic-bezier" => Self::parse_cubic_bezier(context, i),
"steps" => Self::parse_steps(context, i),
"linear" => Self::parse_linear_function(context, i),
_ => Err(location.new_custom_error(StyleParseErrorKind::UnexpectedFunction(function.clone()))),
}
})
}
}
impl TimingFunction {
fn parse_cubic_bezier<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
let x1 = Number::parse(context, input)?;
input.expect_comma()?;
let y1 = Number::parse(context, input)?;
input.expect_comma()?;
let x2 = Number::parse(context, input)?;
input.expect_comma()?;
let y2 = Number::parse(context, input)?;
if x1.get() < 0.0 || x1.get() > 1.0 || x2.get() < 0.0 || x2.get() > 1.0 {
return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
}
Ok(GenericTimingFunction::CubicBezier { x1, y1, x2, y2 })
}
fn parse_steps<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
let steps = Integer::parse_positive(context, input)?;
let position = input
.try_parse(|i| {
i.expect_comma()?;
StepPosition::parse(context, i)
})
.unwrap_or(StepPosition::End);
// jump-none accepts a positive integer greater than 1.
// FIXME(emilio): The spec asks us to avoid rejecting it at parse
// time except until computed value time.
//
// It's not totally clear it's worth it though, and no other browser
// does this.
if position == StepPosition::JumpNone && steps.value() <= 1 {
return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
}
Ok(GenericTimingFunction::Steps(steps, position))
}
fn parse_linear_function<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
let mut builder = PiecewiseLinearFunctionBuilder::default();
let mut num_specified_stops = 0;
// Closely follows `parse_comma_separated`, but can generate multiple entries for one comma-separated entry.
loop {
input.parse_until_before(Delimiter::Comma, |i| {
let builder = &mut builder;
let mut input_start = i.try_parse(|i| Percentage::parse(context, i)).ok();
let mut input_end = i.try_parse(|i| Percentage::parse(context, i)).ok();
let output = Number::parse(context, i)?;
if input_start.is_none() {
debug_assert!(input_end.is_none(), "Input end parsed without input start?");
input_start = i.try_parse(|i| Percentage::parse(context, i)).ok();
input_end = i.try_parse(|i| Percentage::parse(context, i)).ok();
}
builder.push(output.into(), input_start.map(|v| v.get()).into());
num_specified_stops += 1;
if input_end.is_some() {
debug_assert!(
input_start.is_some(),
"Input end valid but not input start?"
);
builder.push(output.into(), input_end.map(|v| v.get()).into());
}
Ok(())
})?;
match input.next() {
Err(_) => break,
Ok(&Token::Comma) => continue,
Ok(_) => unreachable!(),
}
}
// By spec, specifying only a single stop makes the function invalid, even if that single entry may generate
// two entries.
if num_specified_stops < 2 {
return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
}
Ok(GenericTimingFunction::LinearFunction(builder.build()))
}
}
// We need this for converting the specified TimingFunction into computed TimingFunction without
// Context (for some FFIs in glue.rs). In fact, we don't really need Context to get the computed
// value of TimingFunction.
impl TimingFunction {
/// Generate the ComputedTimingFunction without Context.
pub fn to_computed_value_without_context(&self) -> ComputedTimingFunction {
match &self {
GenericTimingFunction::Steps(steps, pos) => {
GenericTimingFunction::Steps(steps.value(), *pos)
},
GenericTimingFunction::CubicBezier { x1, y1, x2, y2 } => {
GenericTimingFunction::CubicBezier {
x1: x1.get(),
y1: y1.get(),
x2: x2.get(),
y2: y2.get(),
}
},
GenericTimingFunction::Keyword(keyword) => GenericTimingFunction::Keyword(*keyword),
GenericTimingFunction::LinearFunction(function) => {
GenericTimingFunction::LinearFunction(function.clone())
},
}
}
}
impl ToComputedValue for TimingFunction {
type ComputedValue = ComputedTimingFunction;
fn to_computed_value(&self, _: &Context) -> Self::ComputedValue {
self.to_computed_value_without_context()
}
fn from_computed_value(computed: &Self::ComputedValue) -> Self {
match &computed {
ComputedTimingFunction::Steps(steps, pos) => Self::Steps(Integer::new(*steps), *pos),
ComputedTimingFunction::CubicBezier { x1, y1, x2, y2 } => Self::CubicBezier {
x1: Number::new(*x1),
y1: Number::new(*y1),
x2: Number::new(*x2),
y2: Number::new(*y2),
},
ComputedTimingFunction::Keyword(keyword) => GenericTimingFunction::Keyword(*keyword),
ComputedTimingFunction::LinearFunction(function) => {
GenericTimingFunction::LinearFunction(function.clone())
},
}
}
}