layout: Implement ordered lists, CSS counters, and quotes per CSS 2.1

§ 12.3-12.5.

Only simple alphabetic and numeric counter styles are supported. (This
is most of them though.)

Although this PR adds a sequential pass to layout, I verified that on
pages that contain a reasonable number of ordered lists (Reddit
`/r/rust`), the time spent in generated content resolution is dwarfed by
the time spent in the parallelizable parts of layout. So I don't expect
this to negatively affect our parallelism expect perhaps in pathological
cases.
This commit is contained in:
Patrick Walton 2015-03-05 12:37:37 -08:00
parent 2df4dd9e09
commit f9cdd05d58
39 changed files with 1704 additions and 537 deletions

View file

@ -0,0 +1,561 @@
/* 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/. */
//! The generated content assignment phase.
//!
//! This phase handles CSS counters, quotes, and ordered lists per CSS § 12.3-12.5. It cannot be
//! done in parallel and is therefore a sequential pass that runs on as little of the flow tree
//! as possible.
use context::LayoutContext;
use flow::{self, AFFECTS_COUNTERS, Flow, HAS_COUNTER_AFFECTING_CHILDREN, ImmutableFlowUtils};
use flow::{InorderFlowTraversal};
use fragment::{Fragment, GeneratedContentInfo, SpecificFragmentInfo, UnscannedTextFragmentInfo};
use incremental::{self, RESOLVE_GENERATED_CONTENT};
use text::TextRunScanner;
use gfx::display_list::OpaqueNode;
use std::collections::{DList, HashMap};
use std::sync::Arc;
use style::computed_values::content::ContentItem;
use style::computed_values::{display, list_style_type};
use style::properties::ComputedValues;
use util::smallvec::{SmallVec, SmallVec8};
// Decimal styles per CSS-COUNTER-STYLES § 6.1:
static DECIMAL: [char; 10] = [ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' ];
// TODO(pcwalton): `decimal-leading-zero`
static ARABIC_INDIC: [char; 10] = [ '٠', '١', '٢', '٣', '٤', '٥', '٦', '٧', '٨', '٩' ];
// TODO(pcwalton): `armenian`, `upper-armenian`, `lower-armenian`
static BENGALI: [char; 10] = [ '', '১', '২', '৩', '', '৫', '৬', '', '৮', '৯' ];
static CAMBODIAN: [char; 10] = [ '០', '១', '២', '៣', '៤', '៥', '៦', '៧', '៨', '៩' ];
// TODO(pcwalton): Suffix for CJK decimal.
static CJK_DECIMAL: [char; 10] = [ '', '一', '二', '三', '四', '五', '六', '七', '八', '九' ];
static DEVANAGARI: [char; 10] = [ '', '१', '२', '३', '४', '५', '६', '७', '८', '९' ];
// TODO(pcwalton): `georgian`
static GUJARATI: [char; 10] = ['', '૧', '૨', '૩', '૪', '૫', '૬', '૭', '૮', '૯'];
static GURMUKHI: [char; 10] = ['', '', '੨', '੩', '', '੫', '੬', '੭', '੮', '੯'];
// TODO(pcwalton): `hebrew`
static KANNADA: [char; 10] = ['', '೧', '೨', '೩', '೪', '೫', '೬', '೭', '೮', '೯'];
static LAO: [char; 10] = ['', '໑', '໒', '໓', '໔', '໕', '໖', '໗', '໘', '໙'];
static MALAYALAM: [char; 10] = ['', '൧', '൨', '൩', '൪', '൫', '൬', '', '൮', '൯'];
static MONGOLIAN: [char; 10] = ['᠐', '᠑', '᠒', '᠓', '᠔', '᠕', '᠖', '᠗', '᠘', '᠙'];
static MYANMAR: [char; 10] = ['', '၁', '၂', '၃', '၄', '၅', '၆', '၇', '၈', '၉'];
static ORIYA: [char; 10] = ['', '୧', '', '୩', '୪', '୫', '୬', '୭', '୮', '୯'];
static PERSIAN: [char; 10] = ['۰', '۱', '۲', '۳', '۴', '۵', '۶', '۷', '۸', '۹'];
// TODO(pcwalton): `lower-roman`, `upper-roman`
static TELUGU: [char; 10] = ['', '౧', '౨', '౩', '౪', '౫', '౬', '౭', '౮', '౯'];
static THAI: [char; 10] = ['', '๑', '๒', '๓', '๔', '๕', '๖', '๗', '๘', '๙'];
static TIBETAN: [char; 10] = ['༠', '༡', '༢', '༣', '༤', '༥', '༦', '༧', '༨', '༩'];
// Alphabetic styles per CSS-COUNTER-STYLES § 6.2:
static LOWER_ALPHA: [char; 26] = [
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
't', 'u', 'v', 'w', 'x', 'y', 'z'
];
static UPPER_ALPHA: [char; 26] = [
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
];
static CJK_EARTHLY_BRANCH: [char; 12] = [
'子', '丑', '寅', '卯', '辰', '巳', '午', '未', '申', '酉', '戌', '亥'
];
static CJK_HEAVENLY_STEM: [char; 10] = [
'甲', '乙', '丙', '丁', '戊', '己', '庚', '辛', '壬', '癸'
];
static LOWER_GREEK: [char; 24] = [
'α', 'β', 'γ', 'δ', 'ε', 'ζ', 'η', 'θ', 'ι', 'κ', 'λ', 'μ', 'ν', 'ξ', 'ο', 'π', 'ρ', 'σ', 'τ',
'υ', 'φ', 'χ', 'ψ', 'ω'
];
static HIRAGANA: [char; 48] = [
'あ', 'い', 'う', 'え', 'お', 'か', 'き', 'く', 'け', 'こ', 'さ', 'し', 'す', 'せ', 'そ',
'た', 'ち', 'つ', 'て', 'と', 'な', 'に', 'ぬ', 'ね', 'の', 'は', 'ひ', 'ふ', 'へ', 'ほ',
'ま', 'み', 'む', 'め', 'も', 'や', 'ゆ', 'よ', 'ら', 'り', 'る', 'れ', 'ろ',
'わ', 'ゐ', 'ゑ', 'を', 'ん'
];
static HIRAGANA_IROHA: [char; 47] = [
'い', 'ろ', 'は', 'に', 'ほ', 'へ', 'と', 'ち', 'り', 'ぬ', 'る', 'を', 'わ', 'か', 'よ',
'た', 'れ', 'そ', 'つ', 'ね', 'な', 'ら', 'む', 'う', 'ゐ', 'の', 'お', 'く', 'や', 'ま',
'け', 'ふ', 'こ', 'え', 'て', 'あ', 'さ', 'き', 'ゆ', 'め', 'み', 'し', 'ゑ',
'ひ', 'も', 'せ', 'す'
];
static KATAKANA: [char; 48] = [
'ア', 'イ', 'ウ', 'エ', 'オ', 'カ', 'キ', 'ク', 'ケ', 'コ', 'サ', 'シ', 'ス', 'セ', 'ソ',
'タ', 'チ', 'ツ', 'テ', 'ト', 'ナ', 'ニ', 'ヌ', 'ネ', '', 'ハ', 'ヒ', 'フ', 'ヘ', 'ホ',
'マ', 'ミ', 'ム', 'メ', 'モ', 'ヤ', 'ユ', 'ヨ', 'ラ', 'リ', 'ル', 'レ', 'ロ',
'ワ', 'ヰ', 'ヱ', 'ヲ', 'ン'
];
static KATAKANA_IROHA: [char; 47] = [
'イ', 'ロ', 'ハ', 'ニ', 'ホ', 'ヘ', 'ト', 'チ', 'リ', 'ヌ', 'ル', 'ヲ', 'ワ', 'カ', 'ヨ',
'タ', 'レ', 'ソ', 'ツ', 'ネ', 'ナ', 'ラ', 'ム', 'ウ', 'ヰ', '', 'オ', 'ク', 'ヤ', 'マ',
'ケ', 'フ', 'コ', 'エ', 'テ', 'ア', 'サ', 'キ', 'ユ', 'メ', 'ミ', 'シ', 'ヱ',
'ヒ', 'モ', 'セ', 'ス'
];
/// The generated content resolution traversal.
pub struct ResolveGeneratedContent<'a> {
/// The layout context.
layout_context: &'a LayoutContext<'a>,
/// The counter representing an ordered list item.
list_item: Counter,
/// Named CSS counters.
counters: HashMap<String,Counter>,
/// The level of quote nesting.
quote: u32,
}
impl<'a> ResolveGeneratedContent<'a> {
/// Creates a new generated content resolution traversal.
pub fn new(layout_context: &'a LayoutContext<'a>) -> ResolveGeneratedContent<'a> {
ResolveGeneratedContent {
layout_context: layout_context,
list_item: Counter::new(),
counters: HashMap::new(),
quote: 0,
}
}
}
impl<'a> InorderFlowTraversal for ResolveGeneratedContent<'a> {
#[inline]
fn process(&mut self, flow: &mut Flow, level: u32) {
let mut mutator = ResolveGeneratedContentFragmentMutator {
traversal: self,
level: level,
is_block: flow.is_block_like(),
incremented: false,
};
flow.mutate_fragments(&mut |fragment| mutator.mutate_fragment(fragment))
}
#[inline]
fn should_process(&mut self, flow: &mut Flow) -> bool {
flow::base(flow).restyle_damage.intersects(RESOLVE_GENERATED_CONTENT) ||
flow::base(flow).flags.intersects(AFFECTS_COUNTERS | HAS_COUNTER_AFFECTING_CHILDREN)
}
}
/// The object that mutates the generated content fragments.
struct ResolveGeneratedContentFragmentMutator<'a,'b:'a> {
/// The traversal.
traversal: &'a mut ResolveGeneratedContent<'b>,
/// The level we're at in the flow tree.
level: u32,
/// Whether this flow is a block flow.
is_block: bool,
/// Whether we've incremented the counter yet.
incremented: bool,
}
impl<'a,'b> ResolveGeneratedContentFragmentMutator<'a,'b> {
fn mutate_fragment(&mut self, fragment: &mut Fragment) {
// We only reset and/or increment counters once per flow. This avoids double-incrementing
// counters on list items (once for the main fragment and once for the marker).
if !self.incremented {
self.reset_and_increment_counters_as_necessary(fragment);
}
let mut list_style_type = fragment.style().get_list().list_style_type;
if fragment.style().get_box().display != display::T::list_item {
list_style_type = list_style_type::T::none
}
let mut new_info = None;
{
let info =
if let SpecificFragmentInfo::GeneratedContent(ref mut info) = fragment.specific {
info
} else {
return
};
match **info {
GeneratedContentInfo::ListItem => {
new_info = self.traversal.list_item.render(self.traversal.layout_context,
fragment.node,
fragment.style.clone(),
list_style_type,
RenderingMode::Suffix(".\u{00a0}"))
}
GeneratedContentInfo::ContentItem(ContentItem::String(_)) => {
// Nothing to do here.
}
GeneratedContentInfo::ContentItem(ContentItem::Counter(ref counter_name,
counter_style)) => {
let mut temporary_counter = Counter::new();
let counter = self.traversal
.counters
.get(counter_name.as_slice())
.unwrap_or(&mut temporary_counter);
new_info = counter.render(self.traversal.layout_context,
fragment.node,
fragment.style.clone(),
counter_style,
RenderingMode::Plain)
}
GeneratedContentInfo::ContentItem(ContentItem::Counters(ref counter_name,
ref separator,
counter_style)) => {
let mut temporary_counter = Counter::new();
let counter = self.traversal
.counters
.get(counter_name.as_slice())
.unwrap_or(&mut temporary_counter);
new_info = counter.render(self.traversal.layout_context,
fragment.node,
fragment.style.clone(),
counter_style,
RenderingMode::All(separator.as_slice()));
}
GeneratedContentInfo::ContentItem(ContentItem::OpenQuote) => {
new_info = Some(render_text(self.traversal.layout_context,
fragment.node,
fragment.style.clone(),
self.quote(&*fragment.style, false)));
self.traversal.quote += 1
}
GeneratedContentInfo::ContentItem(ContentItem::CloseQuote) => {
if self.traversal.quote >= 1 {
self.traversal.quote -= 1
}
new_info = Some(render_text(self.traversal.layout_context,
fragment.node,
fragment.style.clone(),
self.quote(&*fragment.style, true)));
}
GeneratedContentInfo::ContentItem(ContentItem::NoOpenQuote) => {
self.traversal.quote += 1
}
GeneratedContentInfo::ContentItem(ContentItem::NoCloseQuote) => {
if self.traversal.quote >= 1 {
self.traversal.quote -= 1
}
}
}
};
if let Some(new_info) = new_info {
fragment.specific = new_info
}
}
fn reset_and_increment_counters_as_necessary(&mut self, fragment: &mut Fragment) {
let mut list_style_type = fragment.style().get_list().list_style_type;
if !self.is_block || fragment.style().get_box().display != display::T::list_item {
list_style_type = list_style_type::T::none
}
match list_style_type {
list_style_type::T::disc | list_style_type::T::none | list_style_type::T::circle |
list_style_type::T::square | list_style_type::T::disclosure_open |
list_style_type::T::disclosure_closed => {}
_ => self.traversal.list_item.increment(self.level, 1),
}
// Truncate down counters.
for (_, counter) in self.traversal.counters.iter_mut() {
counter.truncate_to_level(self.level);
}
self.traversal.list_item.truncate_to_level(self.level);
for &(ref counter_name, value) in fragment.style().get_counters().counter_reset.0.iter() {
if let Some(ref mut counter) = self.traversal.counters.get_mut(counter_name) {
counter.reset(self.level, value);
continue
}
let mut counter = Counter::new();
counter.reset(self.level, value);
self.traversal.counters.insert((*counter_name).clone(), counter);
}
for &(ref counter_name, value) in fragment.style()
.get_counters()
.counter_increment
.0
.iter() {
if let Some(ref mut counter) = self.traversal.counters.get_mut(counter_name) {
counter.increment(self.level, value);
continue
}
let mut counter = Counter::new();
counter.increment(self.level, value);
self.traversal.counters.insert((*counter_name).clone(), counter);
}
self.incremented = true
}
fn quote(&self, style: &ComputedValues, close: bool) -> String {
let quotes = &style.get_list().quotes;
debug_assert!(!quotes.0.is_empty());
let &(ref open_quote, ref close_quote) =
if self.traversal.quote as uint >= quotes.0.len() {
quotes.0.last().unwrap()
} else {
&quotes.0[self.traversal.quote as uint]
};
if close {
close_quote.to_string()
} else {
open_quote.to_string()
}
}
}
/// A counter per CSS 2.1 § 12.4.
struct Counter {
/// The values at each level.
values: Vec<CounterValue>,
}
impl Counter {
fn new() -> Counter {
Counter {
values: Vec::new(),
}
}
fn reset(&mut self, level: u32, value: i32) {
// Do we have an instance of the counter at this level? If so, just mutate it.
if let Some(ref mut existing_value) = self.values.last_mut() {
if level == existing_value.level {
existing_value.value = value;
return
}
}
// Otherwise, push a new instance of the counter.
self.values.push(CounterValue {
level: level,
value: value,
})
}
fn truncate_to_level(&mut self, level: u32) {
if let Some(position) = self.values.iter().position(|value| value.level > level) {
self.values.truncate(position)
}
}
fn increment(&mut self, level: u32, amount: i32) {
if let Some(ref mut value) = self.values.last_mut() {
value.value += amount;
return
}
self.values.push(CounterValue {
level: level,
value: amount,
})
}
fn render(&self,
layout_context: &LayoutContext,
node: OpaqueNode,
style: Arc<ComputedValues>,
list_style_type: list_style_type::T,
mode: RenderingMode)
-> Option<SpecificFragmentInfo> {
let mut string = String::new();
match mode {
RenderingMode::Plain => {
let value = match self.values.last() {
Some(ref value) => value.value,
None => 0,
};
push_representation(value, list_style_type, &mut string)
}
RenderingMode::Suffix(suffix) => {
let value = match self.values.last() {
Some(ref value) => value.value,
None => 0,
};
push_representation(value, list_style_type, &mut string);
string.push_str(suffix)
}
RenderingMode::All(separator) => {
let mut first = true;
for value in self.values.iter() {
if !first {
string.push_str(separator)
}
first = false;
push_representation(value.value, list_style_type, &mut string)
}
}
}
if string.is_empty() {
None
} else {
Some(render_text(layout_context, node, style, string))
}
}
}
/// How a counter value is to be rendered.
enum RenderingMode<'a> {
/// The innermost counter value is rendered with no extra decoration.
Plain,
/// The innermost counter value is rendered with the given string suffix.
Suffix(&'a str),
/// All values of the counter are rendered with the given separator string between them.
All(&'a str),
}
/// The value of a counter at a given level.
struct CounterValue {
/// The level of the flow tree that this corresponds to.
level: u32,
/// The value of the counter at this level.
value: i32,
}
/// Creates fragment info for a literal string.
fn render_text(layout_context: &LayoutContext,
node: OpaqueNode,
style: Arc<ComputedValues>,
string: String)
-> SpecificFragmentInfo {
let mut fragments = DList::new();
let info = SpecificFragmentInfo::UnscannedText(UnscannedTextFragmentInfo::from_text(string));
fragments.push_back(Fragment::from_opaque_node_and_style(node,
style,
incremental::rebuild_and_reflow(),
info));
let fragments = TextRunScanner::new().scan_for_runs(layout_context.font_context(), fragments);
debug_assert!(fragments.len() == 1);
fragments.fragments.into_iter().next().unwrap().specific
}
/// Appends string that represents the value rendered using the system appropriate for the given
/// `list-style-type` onto the given string.
fn push_representation(value: i32, list_style_type: list_style_type::T, accumulator: &mut String) {
match list_style_type {
list_style_type::T::none => {}
list_style_type::T::disc |
list_style_type::T::circle |
list_style_type::T::square |
list_style_type::T::disclosure_open |
list_style_type::T::disclosure_closed => {
accumulator.push(static_representation(list_style_type))
}
list_style_type::T::decimal => push_numeric_representation(value, &DECIMAL, accumulator),
list_style_type::T::arabic_indic => {
push_numeric_representation(value, &ARABIC_INDIC, accumulator)
}
list_style_type::T::bengali => push_numeric_representation(value, &BENGALI, accumulator),
list_style_type::T::cambodian | list_style_type::T::khmer => {
push_numeric_representation(value, &CAMBODIAN, accumulator)
}
list_style_type::T::cjk_decimal => {
push_numeric_representation(value, &CJK_DECIMAL, accumulator)
}
list_style_type::T::devanagari => {
push_numeric_representation(value, &DEVANAGARI, accumulator)
}
list_style_type::T::gujarati => push_numeric_representation(value, &GUJARATI, accumulator),
list_style_type::T::gurmukhi => push_numeric_representation(value, &GURMUKHI, accumulator),
list_style_type::T::kannada => push_numeric_representation(value, &KANNADA, accumulator),
list_style_type::T::lao => push_numeric_representation(value, &LAO, accumulator),
list_style_type::T::malayalam => {
push_numeric_representation(value, &MALAYALAM, accumulator)
}
list_style_type::T::mongolian => {
push_numeric_representation(value, &MONGOLIAN, accumulator)
}
list_style_type::T::myanmar => push_numeric_representation(value, &MYANMAR, accumulator),
list_style_type::T::oriya => push_numeric_representation(value, &ORIYA, accumulator),
list_style_type::T::persian => push_numeric_representation(value, &PERSIAN, accumulator),
list_style_type::T::telugu => push_numeric_representation(value, &TELUGU, accumulator),
list_style_type::T::thai => push_numeric_representation(value, &THAI, accumulator),
list_style_type::T::tibetan => push_numeric_representation(value, &TIBETAN, accumulator),
list_style_type::T::lower_alpha => {
push_alphabetic_representation(value, &LOWER_ALPHA, accumulator)
}
list_style_type::T::upper_alpha => {
push_alphabetic_representation(value, &UPPER_ALPHA, accumulator)
}
list_style_type::T::cjk_earthly_branch => {
push_alphabetic_representation(value, &CJK_EARTHLY_BRANCH, accumulator)
}
list_style_type::T::cjk_heavenly_stem => {
push_alphabetic_representation(value, &CJK_HEAVENLY_STEM, accumulator)
}
list_style_type::T::lower_greek => {
push_alphabetic_representation(value, &LOWER_GREEK, accumulator)
}
list_style_type::T::hiragana => {
push_alphabetic_representation(value, &HIRAGANA, accumulator)
}
list_style_type::T::hiragana_iroha => {
push_alphabetic_representation(value, &HIRAGANA_IROHA, accumulator)
}
list_style_type::T::katakana => {
push_alphabetic_representation(value, &KATAKANA, accumulator)
}
list_style_type::T::katakana_iroha => {
push_alphabetic_representation(value, &KATAKANA_IROHA, accumulator)
}
}
}
/// Returns the static character that represents the value rendered using the given list-style, if
/// possible.
pub fn static_representation(list_style_type: list_style_type::T) -> char {
match list_style_type {
list_style_type::T::disc => '•',
list_style_type::T::circle => '◦',
list_style_type::T::square => '▪',
list_style_type::T::disclosure_open => '▾',
list_style_type::T::disclosure_closed => '‣',
_ => panic!("No static representation for this list-style-type!"),
}
}
/// Pushes the string that represents the value rendered using the given *alphabetic system* onto
/// the accumulator per CSS-COUNTER-STYLES § 3.1.4.
fn push_alphabetic_representation(mut value: i32, system: &[char], accumulator: &mut String) {
let mut string = SmallVec8::new();
while value != 0 {
// Step 1.
value = value - 1;
// Step 2.
string.push(system[(value as uint) % system.len()]);
// Step 3.
value = ((value as uint) / system.len()) as i32;
}
for i in range(0, string.len()).rev() {
accumulator.push(*string.get(i))
}
}
/// Pushes the string that represents the value rendered using the given *numeric system* onto the
/// accumulator per CSS-COUNTER-STYLES § 3.1.4.
fn push_numeric_representation(mut value: i32, system: &[char], accumulator: &mut String) {
// Step 1.
if value == 0 {
accumulator.push(system[0]);
return
}
// Step 2.
let mut string = SmallVec8::new();
while value != 0 {
// Step 2.1.
string.push(system[(value as uint) % system.len()]);
// Step 2.2.
value = ((value as uint) / system.len()) as i32;
}
// Step 3.
for &ch in string.iter().rev() {
accumulator.push(ch)
}
}