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fune/servo/components/layout/construct.rs
Guillaume Gomez e2ebe34e9f servo: Merge #8675 - Add XMLDocument object (from GuillaumeGomez:master); r=nox 
Fixes #8000

(Still working on it)

Source-Repo: https://github.com/servo/servo
Source-Revision: 99223656fbf6cade8c41d161a9e61a39f58ec796
2015-11-27 19:00:04 +05:01

1815 lines
86 KiB
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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 http://mozilla.org/MPL/2.0/. */
//! Creates flows and fragments from a DOM tree via a bottom-up, incremental traversal of the DOM.
//!
//! Each step of the traversal considers the node and existing flow, if there is one. If a node is
//! not dirty and an existing flow exists, then the traversal reuses that flow. Otherwise, it
//! proceeds to construct either a flow or a `ConstructionItem`. A construction item is a piece of
//! intermediate data that goes with a DOM node and hasn't found its "home" yet-maybe it's a box,
//! maybe it's an absolute or fixed position thing that hasn't found its containing block yet.
//! Construction items bubble up the tree from children to parents until they find their homes.
#![deny(unsafe_code)]
use block::BlockFlow;
use context::LayoutContext;
use data::{HAS_NEWLY_CONSTRUCTED_FLOW, LayoutDataWrapper};
use flex::FlexFlow;
use floats::FloatKind;
use flow::{MutableFlowUtils, MutableOwnedFlowUtils};
use flow::{self, AbsoluteDescendants, Flow, IS_ABSOLUTELY_POSITIONED, ImmutableFlowUtils};
use flow_ref::{self, FlowRef};
use fragment::{CanvasFragmentInfo, ImageFragmentInfo, InlineAbsoluteFragmentInfo};
use fragment::{Fragment, GeneratedContentInfo, IframeFragmentInfo};
use fragment::{InlineAbsoluteHypotheticalFragmentInfo, TableColumnFragmentInfo};
use fragment::{InlineBlockFragmentInfo, SpecificFragmentInfo, UnscannedTextFragmentInfo};
use fragment::{WhitespaceStrippingResult};
use gfx::display_list::OpaqueNode;
use incremental::{BUBBLE_ISIZES, RECONSTRUCT_FLOW, RestyleDamage};
use inline::{FIRST_FRAGMENT_OF_ELEMENT, InlineFlow, InlineFragmentNodeFlags};
use inline::{InlineFragmentNodeInfo, LAST_FRAGMENT_OF_ELEMENT};
use list_item::{ListItemFlow, ListStyleTypeContent};
use multicol::MulticolFlow;
use parallel;
use script::dom::bindings::inheritance::{CharacterDataTypeId, ElementTypeId};
use script::dom::bindings::inheritance::{HTMLElementTypeId, NodeTypeId};
use script::dom::htmlobjectelement::is_image_data;
use std::borrow::ToOwned;
use std::collections::LinkedList;
use std::mem;
use std::sync::Arc;
use std::sync::atomic::Ordering;
use style::computed_values::content::ContentItem;
use style::computed_values::{caption_side, display, empty_cells, float, list_style_position};
use style::computed_values::{position};
use style::properties::{self, ComputedValues};
use table::TableFlow;
use table_caption::TableCaptionFlow;
use table_cell::TableCellFlow;
use table_colgroup::TableColGroupFlow;
use table_row::TableRowFlow;
use table_rowgroup::TableRowGroupFlow;
use table_wrapper::TableWrapperFlow;
use text::TextRunScanner;
use traversal::PostorderNodeMutTraversal;
use url::Url;
use util::linked_list;
use util::opts;
use wrapper::{PseudoElementType, ServoThreadSafeLayoutNode, TextContent, ThreadSafeLayoutElement, ThreadSafeLayoutNode};
/// The results of flow construction for a DOM node.
#[derive(Clone)]
pub enum ConstructionResult {
/// This node contributes nothing at all (`display: none`). Alternately, this is what newly
/// created nodes have their `ConstructionResult` set to.
None,
/// This node contributed a flow at the proper position in the tree.
/// Nothing more needs to be done for this node. It has bubbled up fixed
/// and absolute descendant flows that have a containing block above it.
Flow(FlowRef, AbsoluteDescendants),
/// This node contributed some object or objects that will be needed to construct a proper flow
/// later up the tree, but these objects have not yet found their home.
ConstructionItem(ConstructionItem),
}
impl ConstructionResult {
pub fn swap_out(&mut self) -> ConstructionResult {
if opts::get().nonincremental_layout {
return mem::replace(self, ConstructionResult::None)
}
// FIXME(pcwalton): Stop doing this with inline fragments. Cloning fragments is very
// inefficient!
(*self).clone()
}
pub fn debug_id(&self) -> usize {
match *self {
ConstructionResult::None => 0,
ConstructionResult::ConstructionItem(_) => 0,
ConstructionResult::Flow(ref flow_ref, _) => flow::base(&**flow_ref).debug_id(),
}
}
}
/// Represents the output of flow construction for a DOM node that has not yet resulted in a
/// complete flow. Construction items bubble up the tree until they find a `Flow` to be attached
/// to.
#[derive(Clone)]
pub enum ConstructionItem {
/// Inline fragments and associated {ib} splits that have not yet found flows.
InlineFragments(InlineFragmentsConstructionResult),
/// Potentially ignorable whitespace.
Whitespace(OpaqueNode, PseudoElementType<()>, Arc<ComputedValues>, RestyleDamage),
/// TableColumn Fragment
TableColumnFragment(Fragment),
}
/// Represents inline fragments and {ib} splits that are bubbling up from an inline.
#[derive(Clone)]
pub struct InlineFragmentsConstructionResult {
/// Any {ib} splits that we're bubbling up.
pub splits: LinkedList<InlineBlockSplit>,
/// Any fragments that succeed the {ib} splits.
pub fragments: IntermediateInlineFragments,
}
/// Represents an {ib} split that has not yet found the containing block that it belongs to. This
/// is somewhat tricky. An example may be helpful. For this DOM fragment:
///
/// ```html
/// <span>
/// A
/// <div>B</div>
/// C
/// </span>
/// ```
///
/// The resulting `ConstructionItem` for the outer `span` will be:
///
/// ```ignore
/// ConstructionItem::InlineFragments(Some(~[
/// InlineBlockSplit {
/// predecessor_fragments: ~[
/// A
/// ],
/// block: ~BlockFlow {
/// B
/// },
/// }),~[
/// C
/// ])
/// ```
#[derive(Clone)]
pub struct InlineBlockSplit {
/// The inline fragments that precede the flow.
pub predecessors: IntermediateInlineFragments,
/// The flow that caused this {ib} split.
pub flow: FlowRef,
}
/// Holds inline fragments and absolute descendants.
#[derive(Clone)]
pub struct IntermediateInlineFragments {
/// The list of fragments.
pub fragments: LinkedList<Fragment>,
/// The list of absolute descendants of those inline fragments.
pub absolute_descendants: AbsoluteDescendants,
}
impl IntermediateInlineFragments {
fn new() -> IntermediateInlineFragments {
IntermediateInlineFragments {
fragments: LinkedList::new(),
absolute_descendants: AbsoluteDescendants::new(),
}
}
fn is_empty(&self) -> bool {
self.fragments.is_empty() && self.absolute_descendants.is_empty()
}
fn push_all(&mut self, mut other: IntermediateInlineFragments) {
self.fragments.append(&mut other.fragments);
self.absolute_descendants.push_descendants(other.absolute_descendants);
}
}
/// Holds inline fragments that we're gathering for children of an inline node.
struct InlineFragmentsAccumulator {
/// The list of fragments.
fragments: IntermediateInlineFragments,
/// Whether we've created a range to enclose all the fragments. This will be Some() if the
/// outer node is an inline and None otherwise.
enclosing_node: Option<InlineFragmentNodeInfo>,
/// Restyle damage to use for fragments created in this node.
restyle_damage: RestyleDamage,
/// Bidi control characters to insert before and after these fragments.
bidi_control_chars: Option<(&'static str, &'static str)>,
}
impl InlineFragmentsAccumulator {
fn new() -> InlineFragmentsAccumulator {
InlineFragmentsAccumulator {
fragments: IntermediateInlineFragments::new(),
enclosing_node: None,
bidi_control_chars: None,
restyle_damage: RestyleDamage::empty(),
}
}
fn from_inline_node(node: &ServoThreadSafeLayoutNode) -> InlineFragmentsAccumulator {
InlineFragmentsAccumulator {
fragments: IntermediateInlineFragments::new(),
enclosing_node: Some(InlineFragmentNodeInfo {
address: node.opaque(),
pseudo: node.get_pseudo_element_type().strip(),
style: node.style().clone(),
flags: InlineFragmentNodeFlags::empty(),
}),
bidi_control_chars: None,
restyle_damage: node.restyle_damage(),
}
}
fn push(&mut self, fragment: Fragment) {
self.fragments.fragments.push_back(fragment)
}
fn push_all(&mut self, mut fragments: IntermediateInlineFragments) {
self.fragments.fragments.append(&mut fragments.fragments);
self.fragments.absolute_descendants.push_descendants(fragments.absolute_descendants);
}
fn to_intermediate_inline_fragments(self) -> IntermediateInlineFragments {
let InlineFragmentsAccumulator {
mut fragments,
enclosing_node,
bidi_control_chars,
restyle_damage,
} = self;
if let Some(enclosing_node) = enclosing_node {
let fragment_count = fragments.fragments.len();
for (index, fragment) in fragments.fragments.iter_mut().enumerate() {
let mut enclosing_node = enclosing_node.clone();
if index == 0 {
enclosing_node.flags.insert(FIRST_FRAGMENT_OF_ELEMENT)
}
if index == fragment_count - 1 {
enclosing_node.flags.insert(LAST_FRAGMENT_OF_ELEMENT)
}
fragment.add_inline_context_style(enclosing_node);
}
// Control characters are later discarded in transform_text, so they don't affect the
// is_first/is_last styles above.
if let Some((start, end)) = bidi_control_chars {
fragments.fragments.push_front(
control_chars_to_fragment(&enclosing_node, start, restyle_damage));
fragments.fragments.push_back(
control_chars_to_fragment(&enclosing_node, end, restyle_damage));
}
}
fragments
}
}
/// An object that knows how to create flows.
pub struct FlowConstructor<'a> {
/// The layout context.
pub layout_context: &'a LayoutContext<'a>,
}
impl<'a> FlowConstructor<'a> {
/// Creates a new flow constructor.
pub fn new<'b>(layout_context: &'b LayoutContext<'b>)
-> FlowConstructor<'b> {
FlowConstructor {
layout_context: layout_context,
}
}
#[inline]
fn set_flow_construction_result(&self,
node: &ServoThreadSafeLayoutNode,
result: ConstructionResult) {
node.set_flow_construction_result(result);
}
/// Builds the fragment for the given block or subclass thereof.
fn build_fragment_for_block(&mut self, node: &ServoThreadSafeLayoutNode) -> Fragment {
let specific_fragment_info = match node.type_id() {
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLIFrameElement))) => {
SpecificFragmentInfo::Iframe(box IframeFragmentInfo::new(node))
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLImageElement))) => {
let image_info = box ImageFragmentInfo::new(node,
node.image_url(),
&self.layout_context);
SpecificFragmentInfo::Image(image_info)
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLObjectElement))) => {
let image_info = box ImageFragmentInfo::new(node,
node.object_data(),
&self.layout_context);
SpecificFragmentInfo::Image(image_info)
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTableElement))) => {
SpecificFragmentInfo::TableWrapper
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTableColElement))) => {
SpecificFragmentInfo::TableColumn(TableColumnFragmentInfo::new(node))
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTableCellElement(_)))) => {
SpecificFragmentInfo::TableCell
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTableRowElement))) |
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTableSectionElement))) => {
SpecificFragmentInfo::TableRow
}
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLCanvasElement))) => {
let data = node.canvas_data().unwrap();
SpecificFragmentInfo::Canvas(box CanvasFragmentInfo::new(node, data))
}
_ => {
// This includes pseudo-elements.
SpecificFragmentInfo::Generic
}
};
Fragment::new(node, specific_fragment_info)
}
/// Generates anonymous table objects per CSS 2.1 § 17.2.1.
fn generate_anonymous_table_flows_if_necessary(&mut self,
flow: &mut FlowRef,
child: &mut FlowRef,
child_node: &ServoThreadSafeLayoutNode) {
if !flow.is_block_flow() {
return
}
if child.is_table_cell() {
let mut style = child_node.style().clone();
properties::modify_style_for_anonymous_table_object(&mut style, display::T::table_row);
let fragment = Fragment::from_opaque_node_and_style(child_node.opaque(),
PseudoElementType::Normal,
style,
child_node.restyle_damage(),
SpecificFragmentInfo::TableRow);
let mut new_child: FlowRef = Arc::new(TableRowFlow::from_fragment(fragment));
new_child.add_new_child(child.clone());
child.finish();
*child = new_child
}
if child.is_table_row() || child.is_table_rowgroup() {
let mut style = child_node.style().clone();
properties::modify_style_for_anonymous_table_object(&mut style, display::T::table);
let fragment = Fragment::from_opaque_node_and_style(child_node.opaque(),
PseudoElementType::Normal,
style,
child_node.restyle_damage(),
SpecificFragmentInfo::Table);
let mut new_child: FlowRef = Arc::new(TableFlow::from_fragment(fragment));
new_child.add_new_child(child.clone());
child.finish();
*child = new_child
}
if child.is_table() {
let mut style = child_node.style().clone();
properties::modify_style_for_anonymous_table_object(&mut style, display::T::table);
let fragment =
Fragment::from_opaque_node_and_style(child_node.opaque(),
PseudoElementType::Normal,
style,
child_node.restyle_damage(),
SpecificFragmentInfo::TableWrapper);
let mut new_child: FlowRef = Arc::new(TableWrapperFlow::from_fragment(fragment, None));
new_child.add_new_child(child.clone());
child.finish();
*child = new_child
}
}
/// Creates an inline flow from a set of inline fragments, then adds it as a child of the given
/// flow or pushes it onto the given flow list.
///
/// `#[inline(always)]` because this is performance critical and LLVM will not inline it
/// otherwise.
#[inline(always)]
fn flush_inline_fragments_to_flow_or_list(&mut self,
fragment_accumulator: InlineFragmentsAccumulator,
flow: &mut FlowRef,
flow_list: &mut Vec<FlowRef>,
absolute_descendants: &mut AbsoluteDescendants,
node: &ServoThreadSafeLayoutNode) {
let mut fragments = fragment_accumulator.to_intermediate_inline_fragments();
if fragments.is_empty() {
return
};
strip_ignorable_whitespace_from_start(&mut fragments.fragments);
strip_ignorable_whitespace_from_end(&mut fragments.fragments);
if fragments.fragments.is_empty() {
absolute_descendants.push_descendants(fragments.absolute_descendants);
return
}
// Build a list of all the inline-block fragments before fragments is moved.
let mut inline_block_flows = vec!();
for fragment in &fragments.fragments {
match fragment.specific {
SpecificFragmentInfo::InlineBlock(ref info) => {
inline_block_flows.push(info.flow_ref.clone())
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref info) => {
inline_block_flows.push(info.flow_ref.clone())
}
SpecificFragmentInfo::InlineAbsolute(ref info) => {
inline_block_flows.push(info.flow_ref.clone())
}
_ => {}
}
}
// We must scan for runs before computing minimum ascent and descent because scanning
// for runs might collapse so much whitespace away that only hypothetical fragments
// remain. In that case the inline flow will compute its ascent and descent to be zero.
let scanned_fragments =
TextRunScanner::new().scan_for_runs(&mut self.layout_context.font_context(),
fragments.fragments);
let mut inline_flow_ref: FlowRef = Arc::new(
InlineFlow::from_fragments(scanned_fragments, node.style().writing_mode));
// Add all the inline-block fragments as children of the inline flow.
for inline_block_flow in &inline_block_flows {
inline_flow_ref.add_new_child(inline_block_flow.clone());
}
// Set up absolute descendants as necessary.
//
// The inline flow itself may need to become the containing block for absolute descendants
// in order to handle cases like:
//
// <div>
// <span style="position: relative">
// <span style="position: absolute; ..."></span>
// </span>
// </div>
//
// See the comment above `flow::AbsoluteDescendantInfo` for more information.
inline_flow_ref.take_applicable_absolute_descendants(&mut fragments.absolute_descendants);
absolute_descendants.push_descendants(fragments.absolute_descendants);
{
// FIXME(#6503): Use Arc::get_mut().unwrap() here.
let inline_flow = flow_ref::deref_mut(&mut inline_flow_ref).as_mut_inline();
let (ascent, descent) =
inline_flow.compute_minimum_ascent_and_descent(&mut self.layout_context
.font_context(),
&**node.style());
inline_flow.minimum_block_size_above_baseline = ascent;
inline_flow.minimum_depth_below_baseline = descent;
}
inline_flow_ref.finish();
if flow.need_anonymous_flow(&*inline_flow_ref) {
flow_list.push(inline_flow_ref)
} else {
flow.add_new_child(inline_flow_ref)
}
}
fn build_block_flow_using_construction_result_of_child(
&mut self,
flow: &mut FlowRef,
consecutive_siblings: &mut Vec<FlowRef>,
node: &ServoThreadSafeLayoutNode,
kid: ServoThreadSafeLayoutNode,
inline_fragment_accumulator: &mut InlineFragmentsAccumulator,
abs_descendants: &mut AbsoluteDescendants) {
match kid.swap_out_construction_result() {
ConstructionResult::None => {}
ConstructionResult::Flow(mut kid_flow, kid_abs_descendants) => {
// If kid_flow is TableCaptionFlow, kid_flow should be added under
// TableWrapperFlow.
if flow.is_table() && kid_flow.is_table_caption() {
self.set_flow_construction_result(&kid,
ConstructionResult::Flow(kid_flow,
AbsoluteDescendants::new()))
} else if flow.need_anonymous_flow(&*kid_flow) {
consecutive_siblings.push(kid_flow)
} else {
// Flush any inline fragments that we were gathering up. This allows us to
// handle {ib} splits.
debug!("flushing {} inline box(es) to flow A",
inline_fragment_accumulator.fragments.fragments.len());
let old_inline_fragment_accumulator =
mem::replace(inline_fragment_accumulator,
InlineFragmentsAccumulator::new());
self.flush_inline_fragments_to_flow_or_list(
old_inline_fragment_accumulator,
flow,
consecutive_siblings,
abs_descendants,
node);
if !consecutive_siblings.is_empty() {
let consecutive_siblings = mem::replace(consecutive_siblings, vec!());
self.generate_anonymous_missing_child(consecutive_siblings, flow, node);
}
self.generate_anonymous_table_flows_if_necessary(flow, &mut kid_flow, &kid);
flow.add_new_child(kid_flow);
}
abs_descendants.push_descendants(kid_abs_descendants);
}
ConstructionResult::ConstructionItem(ConstructionItem::InlineFragments(
InlineFragmentsConstructionResult {
splits,
fragments: successor_fragments,
})) => {
// Add any {ib} splits.
for split in splits {
// Pull apart the {ib} split object and push its predecessor fragments
// onto the list.
let InlineBlockSplit {
predecessors,
flow: kid_flow
} = split;
inline_fragment_accumulator.push_all(predecessors);
// Flush any inline fragments that we were gathering up.
debug!("flushing {} inline box(es) to flow A",
inline_fragment_accumulator.fragments.fragments.len());
let old_inline_fragment_accumulator =
mem::replace(inline_fragment_accumulator,
InlineFragmentsAccumulator::new());
self.flush_inline_fragments_to_flow_or_list(
old_inline_fragment_accumulator,
flow,
consecutive_siblings,
&mut inline_fragment_accumulator.fragments.absolute_descendants,
node);
// Push the flow generated by the {ib} split onto our list of
// flows.
if flow.need_anonymous_flow(&*kid_flow) {
consecutive_siblings.push(kid_flow)
} else {
flow.add_new_child(kid_flow)
}
}
// Add the fragments to the list we're maintaining.
inline_fragment_accumulator.push_all(successor_fragments);
}
ConstructionResult::ConstructionItem(ConstructionItem::Whitespace(
whitespace_node,
whitespace_pseudo,
mut whitespace_style,
whitespace_damage)) => {
// Add whitespace results. They will be stripped out later on when
// between block elements, and retained when between inline elements.
let fragment_info = SpecificFragmentInfo::UnscannedText(
UnscannedTextFragmentInfo::new(" ".to_owned(), None));
properties::modify_style_for_replaced_content(&mut whitespace_style);
properties::modify_style_for_text(&mut whitespace_style);
let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
whitespace_pseudo,
whitespace_style,
whitespace_damage,
fragment_info);
inline_fragment_accumulator.fragments.fragments.push_back(fragment);
}
ConstructionResult::ConstructionItem(ConstructionItem::TableColumnFragment(_)) => {
// TODO: Implement anonymous table objects for missing parents
// CSS 2.1 § 17.2.1, step 3-2
}
}
}
/// Constructs a block flow, beginning with the given `initial_fragments` if present and then
/// appending the construction results of children to the child list of the block flow. {ib}
/// splits and absolutely-positioned descendants are handled correctly.
fn build_flow_for_block_starting_with_fragments(
&mut self,
mut flow: FlowRef,
node: &ServoThreadSafeLayoutNode,
initial_fragments: IntermediateInlineFragments)
-> ConstructionResult {
// Gather up fragments for the inline flows we might need to create.
let mut inline_fragment_accumulator = InlineFragmentsAccumulator::new();
let mut consecutive_siblings = vec!();
inline_fragment_accumulator.fragments.push_all(initial_fragments);
// List of absolute descendants, in tree order.
let mut abs_descendants = AbsoluteDescendants::new();
for kid in node.children() {
if kid.get_pseudo_element_type() != PseudoElementType::Normal {
self.process(&kid);
}
self.build_block_flow_using_construction_result_of_child(
&mut flow,
&mut consecutive_siblings,
node,
kid,
&mut inline_fragment_accumulator,
&mut abs_descendants);
}
// Perform a final flush of any inline fragments that we were gathering up to handle {ib}
// splits, after stripping ignorable whitespace.
self.flush_inline_fragments_to_flow_or_list(inline_fragment_accumulator,
&mut flow,
&mut consecutive_siblings,
&mut abs_descendants,
node);
if !consecutive_siblings.is_empty() {
self.generate_anonymous_missing_child(consecutive_siblings, &mut flow, node);
}
// The flow is done.
flow.finish();
// Set up the absolute descendants.
let contains_positioned_fragments = flow.contains_positioned_fragments();
let is_absolutely_positioned = flow::base(&*flow).flags.contains(IS_ABSOLUTELY_POSITIONED);
if contains_positioned_fragments {
// This is the containing block for all the absolute descendants.
flow.set_absolute_descendants(abs_descendants);
abs_descendants = AbsoluteDescendants::new();
if is_absolutely_positioned {
// This is now the only absolute flow in the subtree which hasn't yet
// reached its CB.
abs_descendants.push(flow.clone());
}
}
ConstructionResult::Flow(flow, abs_descendants)
}
/// Constructs a flow for the given block node and its children. This method creates an
/// initial fragment as appropriate and then dispatches to
/// `build_flow_for_block_starting_with_fragments`. Currently the following kinds of flows get
/// initial content:
///
/// * Generated content gets the initial content specified by the `content` attribute of the
/// CSS.
/// * `<input>` and `<textarea>` elements get their content.
///
/// FIXME(pcwalton): It is not clear to me that there isn't a cleaner way to handle
/// `<textarea>`.
fn build_flow_for_block_like(&mut self, flow: FlowRef, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let mut initial_fragments = IntermediateInlineFragments::new();
let node_is_input_or_text_area =
node.type_id() == Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLInputElement))) ||
node.type_id() == Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTextAreaElement)));
if node.get_pseudo_element_type() != PseudoElementType::Normal ||
node_is_input_or_text_area {
// A TextArea's text contents are displayed through the input text
// box, so don't construct them.
if node.type_id() == Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLTextAreaElement))) {
for kid in node.children() {
self.set_flow_construction_result(&kid, ConstructionResult::None)
}
}
let mut style = node.style().clone();
if node_is_input_or_text_area {
properties::modify_style_for_input_text(&mut style);
}
self.create_fragments_for_node_text_content(&mut initial_fragments, node, &style)
}
self.build_flow_for_block_starting_with_fragments(flow, node, initial_fragments)
}
/// Pushes fragments appropriate for the content of the given node onto the given list.
fn create_fragments_for_node_text_content(&self,
fragments: &mut IntermediateInlineFragments,
node: &ServoThreadSafeLayoutNode,
style: &Arc<ComputedValues>) {
// Fast path: If there is no text content, return immediately.
let text_content = node.text_content();
if text_content.is_empty() {
return
}
let insertion_point = node.insertion_point();
let mut style = (*style).clone();
properties::modify_style_for_text(&mut style);
match text_content {
TextContent::Text(string) => {
let info = UnscannedTextFragmentInfo::new(string, insertion_point);
let specific_fragment_info = SpecificFragmentInfo::UnscannedText(info);
fragments.fragments.push_back(Fragment::from_opaque_node_and_style(
node.opaque(),
node.get_pseudo_element_type().strip(),
style.clone(),
node.restyle_damage(),
specific_fragment_info))
}
TextContent::GeneratedContent(content_items) => {
for content_item in content_items.into_iter() {
let specific_fragment_info = match content_item {
ContentItem::String(string) => {
let info = UnscannedTextFragmentInfo::new(string, None);
SpecificFragmentInfo::UnscannedText(info)
}
content_item => {
let content_item = box GeneratedContentInfo::ContentItem(content_item);
SpecificFragmentInfo::GeneratedContent(content_item)
}
};
fragments.fragments.push_back(Fragment::from_opaque_node_and_style(
node.opaque(),
node.get_pseudo_element_type().strip(),
style.clone(),
node.restyle_damage(),
specific_fragment_info))
}
}
}
}
/// Builds a flow for a node with `display: block`. This yields a `BlockFlow` with possibly
/// other `BlockFlow`s or `InlineFlow`s underneath it, depending on whether {ib} splits needed
/// to happen.
fn build_flow_for_block(&mut self, node: &ServoThreadSafeLayoutNode, float_kind: Option<FloatKind>)
-> ConstructionResult {
let fragment = self.build_fragment_for_block(node);
let flow: FlowRef = if node.style().is_multicol() {
Arc::new(MulticolFlow::from_fragment(fragment, float_kind))
} else {
Arc::new(BlockFlow::from_fragment(fragment, float_kind))
};
self.build_flow_for_block_like(flow, node)
}
/// Bubbles up {ib} splits.
fn accumulate_inline_block_splits(&mut self,
splits: LinkedList<InlineBlockSplit>,
node: &ServoThreadSafeLayoutNode,
fragment_accumulator: &mut InlineFragmentsAccumulator,
opt_inline_block_splits: &mut LinkedList<InlineBlockSplit>) {
for split in splits {
let InlineBlockSplit {
predecessors,
flow: kid_flow
} = split;
fragment_accumulator.push_all(predecessors);
let split = InlineBlockSplit {
predecessors: mem::replace(
fragment_accumulator,
InlineFragmentsAccumulator::from_inline_node(
node)).to_intermediate_inline_fragments(),
flow: kid_flow,
};
opt_inline_block_splits.push_back(split)
}
}
/// Concatenates the fragments of kids, adding in our own borders/padding/margins if necessary.
/// Returns the `InlineFragmentsConstructionResult`, if any. There will be no
/// `InlineFragmentsConstructionResult` if this node consisted entirely of ignorable
/// whitespace.
fn build_fragments_for_nonreplaced_inline_content(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let mut opt_inline_block_splits: LinkedList<InlineBlockSplit> = LinkedList::new();
let mut fragment_accumulator = InlineFragmentsAccumulator::from_inline_node(node);
fragment_accumulator.bidi_control_chars = bidi_control_chars(&*node.style());
let mut abs_descendants = AbsoluteDescendants::new();
// Concatenate all the fragments of our kids, creating {ib} splits as necessary.
for kid in node.children() {
if kid.get_pseudo_element_type() != PseudoElementType::Normal {
self.process(&kid);
}
match kid.swap_out_construction_result() {
ConstructionResult::None => {}
ConstructionResult::Flow(flow, kid_abs_descendants) => {
if !flow::base(&*flow).flags.contains(IS_ABSOLUTELY_POSITIONED) {
// {ib} split. Flush the accumulator to our new split and make a new
// accumulator to hold any subsequent fragments we come across.
let split = InlineBlockSplit {
predecessors:
mem::replace(
&mut fragment_accumulator,
InlineFragmentsAccumulator::from_inline_node(
node)).to_intermediate_inline_fragments(),
flow: flow,
};
opt_inline_block_splits.push_back(split);
abs_descendants.push_descendants(kid_abs_descendants);
} else {
// Push the absolutely-positioned kid as an inline containing block.
let kid_node = flow.as_block().fragment.node;
let kid_pseudo = flow.as_block().fragment.pseudo.clone();
let kid_style = flow.as_block().fragment.style.clone();
let kid_restyle_damage = flow.as_block().fragment.restyle_damage;
let fragment_info = SpecificFragmentInfo::InlineAbsolute(
InlineAbsoluteFragmentInfo::new(flow));
fragment_accumulator.push(Fragment::from_opaque_node_and_style(
kid_node,
kid_pseudo,
kid_style,
kid_restyle_damage,
fragment_info));
fragment_accumulator.fragments
.absolute_descendants
.push_descendants(kid_abs_descendants);
}
}
ConstructionResult::ConstructionItem(ConstructionItem::InlineFragments(
InlineFragmentsConstructionResult {
splits,
fragments: successors,
})) => {
// Bubble up {ib} splits.
self.accumulate_inline_block_splits(splits,
node,
&mut fragment_accumulator,
&mut opt_inline_block_splits);
// Push residual fragments.
fragment_accumulator.push_all(successors);
}
ConstructionResult::ConstructionItem(ConstructionItem::Whitespace(
whitespace_node,
whitespace_pseudo,
mut whitespace_style,
whitespace_damage)) => {
// Instantiate the whitespace fragment.
let fragment_info = SpecificFragmentInfo::UnscannedText(
UnscannedTextFragmentInfo::new(" ".to_owned(), None));
properties::modify_style_for_replaced_content(&mut whitespace_style);
properties::modify_style_for_text(&mut whitespace_style);
let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
whitespace_pseudo,
whitespace_style,
whitespace_damage,
fragment_info);
fragment_accumulator.fragments.fragments.push_back(fragment)
}
ConstructionResult::ConstructionItem(ConstructionItem::TableColumnFragment(_)) => {
// TODO: Implement anonymous table objects for missing parents
// CSS 2.1 § 17.2.1, step 3-2
}
}
}
// Finally, make a new construction result.
if opt_inline_block_splits.len() > 0 || !fragment_accumulator.fragments.is_empty()
|| abs_descendants.len() > 0 {
fragment_accumulator.fragments.absolute_descendants.push_descendants(abs_descendants);
// If the node is positioned, then it's the containing block for all absolutely-
// positioned descendants.
if node.style().get_box().position != position::T::static_ {
fragment_accumulator.fragments
.absolute_descendants
.mark_as_having_reached_containing_block();
}
let construction_item = ConstructionItem::InlineFragments(
InlineFragmentsConstructionResult {
splits: opt_inline_block_splits,
fragments: fragment_accumulator.to_intermediate_inline_fragments(),
});
ConstructionResult::ConstructionItem(construction_item)
} else {
ConstructionResult::None
}
}
/// Creates an `InlineFragmentsConstructionResult` for replaced content. Replaced content
/// doesn't render its children, so this just nukes a child's fragments and creates a
/// `Fragment`.
fn build_fragments_for_replaced_inline_content(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
for kid in node.children() {
self.set_flow_construction_result(&kid, ConstructionResult::None)
}
// If this node is ignorable whitespace, bail out now.
//
// FIXME(#2001, pcwalton): Don't do this if there's padding or borders.
if node.is_ignorable_whitespace() {
return ConstructionResult::ConstructionItem(ConstructionItem::Whitespace(
node.opaque(),
node.get_pseudo_element_type().strip(),
node.style().clone(),
node.restyle_damage()))
}
// Modify the style as necessary. (See the comment in
// `properties::modify_style_for_replaced_content()`.)
let mut style = (*node.style()).clone();
properties::modify_style_for_replaced_content(&mut style);
// If this is generated content, then we need to initialize the accumulator with the
// fragment corresponding to that content. Otherwise, just initialize with the ordinary
// fragment that needs to be generated for this inline node.
let mut fragments = IntermediateInlineFragments::new();
match (node.get_pseudo_element_type(), node.type_id()) {
(_, Some(NodeTypeId::CharacterData(CharacterDataTypeId::Text))) => {
self.create_fragments_for_node_text_content(&mut fragments, node, &style)
}
(PseudoElementType::Normal, _) => {
fragments.fragments.push_back(self.build_fragment_for_block(node));
}
(_, _) => self.create_fragments_for_node_text_content(&mut fragments, node, &style),
}
let construction_item =
ConstructionItem::InlineFragments(InlineFragmentsConstructionResult {
splits: LinkedList::new(),
fragments: fragments,
});
ConstructionResult::ConstructionItem(construction_item)
}
fn build_fragment_for_inline_block(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let block_flow_result = self.build_flow_for_block(node, None);
let (block_flow, abs_descendants) = match block_flow_result {
ConstructionResult::Flow(block_flow, abs_descendants) => (block_flow, abs_descendants),
_ => unreachable!()
};
let mut modified_style = (*node.style()).clone();
properties::modify_style_for_outer_inline_block_fragment(&mut modified_style);
let fragment_info = SpecificFragmentInfo::InlineBlock(InlineBlockFragmentInfo::new(
block_flow));
let fragment = Fragment::from_opaque_node_and_style(node.opaque(),
node.get_pseudo_element_type().strip(),
modified_style.clone(),
node.restyle_damage(),
fragment_info);
let mut fragment_accumulator = InlineFragmentsAccumulator::new();
fragment_accumulator.fragments.fragments.push_back(fragment);
fragment_accumulator.fragments.absolute_descendants.push_descendants(abs_descendants);
let construction_item =
ConstructionItem::InlineFragments(InlineFragmentsConstructionResult {
splits: LinkedList::new(),
fragments: fragment_accumulator.to_intermediate_inline_fragments(),
});
ConstructionResult::ConstructionItem(construction_item)
}
/// This is an annoying case, because the computed `display` value is `block`, but the
/// hypothetical box is inline.
fn build_fragment_for_absolutely_positioned_inline(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let block_flow_result = self.build_flow_for_block(node, None);
let (block_flow, abs_descendants) = match block_flow_result {
ConstructionResult::Flow(block_flow, abs_descendants) => (block_flow, abs_descendants),
_ => unreachable!()
};
let fragment_info = SpecificFragmentInfo::InlineAbsoluteHypothetical(
InlineAbsoluteHypotheticalFragmentInfo::new(block_flow));
let mut style = node.style().clone();
properties::modify_style_for_inline_absolute_hypothetical_fragment(&mut style);
let fragment = Fragment::from_opaque_node_and_style(node.opaque(),
PseudoElementType::Normal,
style,
node.restyle_damage(),
fragment_info);
let mut fragment_accumulator = InlineFragmentsAccumulator::from_inline_node(node);
fragment_accumulator.fragments.fragments.push_back(fragment);
fragment_accumulator.fragments.absolute_descendants.push_descendants(abs_descendants);
let construction_item =
ConstructionItem::InlineFragments(InlineFragmentsConstructionResult {
splits: LinkedList::new(),
fragments: fragment_accumulator.to_intermediate_inline_fragments(),
});
ConstructionResult::ConstructionItem(construction_item)
}
/// Builds one or more fragments for a node with `display: inline`. This yields an
/// `InlineFragmentsConstructionResult`.
fn build_fragments_for_inline(&mut self, node: &ServoThreadSafeLayoutNode) -> ConstructionResult {
// Is this node replaced content?
if !node.is_replaced_content() {
// Go to a path that concatenates our kids' fragments.
self.build_fragments_for_nonreplaced_inline_content(node)
} else {
// Otherwise, just nuke our kids' fragments, create our fragment if any, and be done
// with it.
self.build_fragments_for_replaced_inline_content(node)
}
}
/// Places any table captions found under the given table wrapper, if the value of their
/// `caption-side` property is equal to the given `side`.
fn place_table_caption_under_table_wrapper_on_side(&mut self,
table_wrapper_flow: &mut FlowRef,
node: &ServoThreadSafeLayoutNode,
side: caption_side::T) {
// Only flows that are table captions are matched here.
for kid in node.children() {
match kid.swap_out_construction_result() {
ConstructionResult::Flow(kid_flow, _) => {
if kid_flow.is_table_caption() &&
kid_flow.as_block()
.fragment
.style()
.get_inheritedtable()
.caption_side == side {
table_wrapper_flow.add_new_child(kid_flow);
}
}
ConstructionResult::None | ConstructionResult::ConstructionItem(_) => {}
}
}
}
/// Generates an anonymous table flow according to CSS 2.1 § 17.2.1, step 2.
/// If necessary, generate recursively another anonymous table flow.
fn generate_anonymous_missing_child(&mut self,
child_flows: Vec<FlowRef>,
flow: &mut FlowRef,
node: &ServoThreadSafeLayoutNode) {
let mut anonymous_flow = flow.generate_missing_child_flow(node);
let mut consecutive_siblings = vec!();
for kid_flow in child_flows {
if anonymous_flow.need_anonymous_flow(&*kid_flow) {
consecutive_siblings.push(kid_flow);
continue;
}
if !consecutive_siblings.is_empty() {
self.generate_anonymous_missing_child(consecutive_siblings,
&mut anonymous_flow,
node);
consecutive_siblings = vec!();
}
anonymous_flow.add_new_child(kid_flow);
}
if !consecutive_siblings.is_empty() {
self.generate_anonymous_missing_child(consecutive_siblings, &mut anonymous_flow, node);
}
// The flow is done.
anonymous_flow.finish();
flow.add_new_child(anonymous_flow);
}
/// Builds a flow for a node with `display: table`. This yields a `TableWrapperFlow` with
/// possibly other `TableCaptionFlow`s or `TableFlow`s underneath it.
fn build_flow_for_table_wrapper(&mut self, node: &ServoThreadSafeLayoutNode, float_value: float::T)
-> ConstructionResult {
let fragment = Fragment::new(node, SpecificFragmentInfo::TableWrapper);
let mut wrapper_flow: FlowRef = Arc::new(
TableWrapperFlow::from_fragment(fragment, FloatKind::from_property(float_value)));
let table_fragment = Fragment::new(node, SpecificFragmentInfo::Table);
let table_flow = Arc::new(TableFlow::from_fragment(table_fragment));
// First populate the table flow with its children.
let construction_result = self.build_flow_for_block_like(table_flow, node);
let mut abs_descendants = AbsoluteDescendants::new();
let mut fixed_descendants = AbsoluteDescendants::new();
// The order of the caption and the table are not necessarily the same order as in the DOM
// tree. All caption blocks are placed before or after the table flow, depending on the
// value of `caption-side`.
self.place_table_caption_under_table_wrapper_on_side(&mut wrapper_flow,
node,
caption_side::T::top);
match construction_result {
ConstructionResult::Flow(table_flow, table_abs_descendants) => {
wrapper_flow.add_new_child(table_flow);
abs_descendants.push_descendants(table_abs_descendants);
}
_ => {}
}
// If the value of `caption-side` is `bottom`, place it now.
self.place_table_caption_under_table_wrapper_on_side(&mut wrapper_flow,
node,
caption_side::T::bottom);
// The flow is done.
wrapper_flow.finish();
let contains_positioned_fragments = wrapper_flow.contains_positioned_fragments();
let is_fixed_positioned = wrapper_flow.as_block().is_fixed();
let is_absolutely_positioned =
flow::base(&*wrapper_flow).flags.contains(IS_ABSOLUTELY_POSITIONED);
if contains_positioned_fragments {
// This is the containing block for all the absolute descendants.
wrapper_flow.set_absolute_descendants(abs_descendants);
abs_descendants = AbsoluteDescendants::new();
if is_fixed_positioned {
// Send itself along with the other fixed descendants.
fixed_descendants.push(wrapper_flow.clone());
} else if is_absolutely_positioned {
// This is now the only absolute flow in the subtree which hasn't yet
// reached its containing block.
abs_descendants.push(wrapper_flow.clone());
}
}
ConstructionResult::Flow(wrapper_flow, abs_descendants)
}
/// Builds a flow for a node with `display: table-caption`. This yields a `TableCaptionFlow`
/// with possibly other `BlockFlow`s or `InlineFlow`s underneath it.
fn build_flow_for_table_caption(&mut self, node: &ServoThreadSafeLayoutNode) -> ConstructionResult {
let fragment = self.build_fragment_for_block(node);
let flow = Arc::new(TableCaptionFlow::from_fragment(fragment));
self.build_flow_for_block_like(flow, node)
}
/// Builds a flow for a node with `display: table-row-group`. This yields a `TableRowGroupFlow`
/// with possibly other `TableRowFlow`s underneath it.
fn build_flow_for_table_rowgroup(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let fragment = Fragment::new(node, SpecificFragmentInfo::TableRow);
let flow = Arc::new(TableRowGroupFlow::from_fragment(fragment));
self.build_flow_for_block_like(flow, node)
}
/// Builds a flow for a node with `display: table-row`. This yields a `TableRowFlow` with
/// possibly other `TableCellFlow`s underneath it.
fn build_flow_for_table_row(&mut self, node: &ServoThreadSafeLayoutNode) -> ConstructionResult {
let fragment = Fragment::new(node, SpecificFragmentInfo::TableRow);
let flow = Arc::new(TableRowFlow::from_fragment(fragment));
self.build_flow_for_block_like(flow, node)
}
/// Builds a flow for a node with `display: table-cell`. This yields a `TableCellFlow` with
/// possibly other `BlockFlow`s or `InlineFlow`s underneath it.
fn build_flow_for_table_cell(&mut self, node: &ServoThreadSafeLayoutNode) -> ConstructionResult {
let fragment = Fragment::new(node, SpecificFragmentInfo::TableCell);
// Determine if the table cell should be hidden. Per CSS 2.1 § 17.6.1.1, this will be true
// if the cell has any in-flow elements (even empty ones!) and has `empty-cells` set to
// `hide`.
let hide = node.style().get_inheritedtable().empty_cells == empty_cells::T::hide &&
node.children().all(|kid| {
let position = kid.style().get_box().position;
!kid.is_content() ||
position == position::T::absolute ||
position == position::T::fixed
});
let flow = Arc::new(
TableCellFlow::from_node_fragment_and_visibility_flag(node, fragment, !hide));
self.build_flow_for_block_like(flow, node)
}
/// Builds a flow for a node with `display: list-item`. This yields a `ListItemFlow` with
/// possibly other `BlockFlow`s or `InlineFlow`s underneath it.
fn build_flow_for_list_item(&mut self, node: &ServoThreadSafeLayoutNode, flotation: float::T)
-> ConstructionResult {
let flotation = FloatKind::from_property(flotation);
let marker_fragments = match node.style().get_list().list_style_image.0 {
Some(ref url) => {
let image_info = box ImageFragmentInfo::new(node,
Some((*url).clone()),
&self.layout_context);
vec![Fragment::new(node, SpecificFragmentInfo::Image(image_info))]
}
None => {
match ListStyleTypeContent::from_list_style_type(node.style()
.get_list()
.list_style_type) {
ListStyleTypeContent::None => Vec::new(),
ListStyleTypeContent::StaticText(ch) => {
let text = format!("{}\u{a0}", ch);
let mut unscanned_marker_fragments = LinkedList::new();
unscanned_marker_fragments.push_back(Fragment::new(
node,
SpecificFragmentInfo::UnscannedText(
UnscannedTextFragmentInfo::new(text, None))));
let marker_fragments = TextRunScanner::new().scan_for_runs(
&mut self.layout_context.font_context(),
unscanned_marker_fragments);
marker_fragments.fragments
}
ListStyleTypeContent::GeneratedContent(info) => {
vec![Fragment::new(node, SpecificFragmentInfo::GeneratedContent(info))]
}
}
}
};
// If the list marker is outside, it becomes the special "outside fragment" that list item
// flows have. If it's inside, it's just a plain old fragment. Note that this means that
// we adopt Gecko's behavior rather than WebKit's when the marker causes an {ib} split,
// which has caused some malaise (Bugzilla #36854) but CSS 2.1 § 12.5.1 lets me do it, so
// there.
let mut initial_fragments = IntermediateInlineFragments::new();
let main_fragment = self.build_fragment_for_block(node);
let flow = match node.style().get_list().list_style_position {
list_style_position::T::outside => {
Arc::new(ListItemFlow::from_fragments_and_flotation(
main_fragment, marker_fragments, flotation))
}
list_style_position::T::inside => {
for marker_fragment in marker_fragments {
initial_fragments.fragments.push_back(marker_fragment)
}
Arc::new(ListItemFlow::from_fragments_and_flotation(
main_fragment, vec![], flotation))
}
};
self.build_flow_for_block_starting_with_fragments(flow, node, initial_fragments)
}
/// Creates a fragment for a node with `display: table-column`.
fn build_fragments_for_table_column(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
// CSS 2.1 § 17.2.1. Treat all child fragments of a `table-column` as `display: none`.
for kid in node.children() {
self.set_flow_construction_result(&kid, ConstructionResult::None)
}
let specific = SpecificFragmentInfo::TableColumn(TableColumnFragmentInfo::new(node));
let construction_item = ConstructionItem::TableColumnFragment(Fragment::new(node,
specific));
ConstructionResult::ConstructionItem(construction_item)
}
/// Builds a flow for a node with `display: table-column-group`.
/// This yields a `TableColGroupFlow`.
fn build_flow_for_table_colgroup(&mut self, node: &ServoThreadSafeLayoutNode)
-> ConstructionResult {
let fragment =
Fragment::new(node,
SpecificFragmentInfo::TableColumn(TableColumnFragmentInfo::new(node)));
let mut col_fragments = vec!();
for kid in node.children() {
// CSS 2.1 § 17.2.1. Treat all non-column child fragments of `table-column-group`
// as `display: none`.
match kid.swap_out_construction_result() {
ConstructionResult::ConstructionItem(ConstructionItem::TableColumnFragment(
fragment)) => {
col_fragments.push(fragment);
}
_ => {}
}
}
if col_fragments.is_empty() {
debug!("add SpecificFragmentInfo::TableColumn for empty colgroup");
let specific = SpecificFragmentInfo::TableColumn(TableColumnFragmentInfo::new(node));
col_fragments.push(Fragment::new(node, specific));
}
let mut flow: FlowRef = Arc::new(TableColGroupFlow::from_fragments(fragment, col_fragments));
flow.finish();
ConstructionResult::Flow(flow, AbsoluteDescendants::new())
}
/// Builds a flow for a node with 'display: flex'.
fn build_flow_for_flex(&mut self, node: &ServoThreadSafeLayoutNode, float_kind: Option<FloatKind>)
-> ConstructionResult {
let fragment = self.build_fragment_for_block(node);
let flow = Arc::new(FlexFlow::from_fragment(fragment, float_kind));
self.build_flow_for_block_like(flow, node)
}
/// Attempts to perform incremental repair to account for recent changes to this node. This
/// can fail and return false, indicating that flows will need to be reconstructed.
///
/// TODO(pcwalton): Add some more fast paths, like toggling `display: none`, adding block kids
/// to block parents with no {ib} splits, adding out-of-flow kids, etc.
pub fn repair_if_possible(&mut self, node: &ServoThreadSafeLayoutNode) -> bool {
// We can skip reconstructing the flow if we don't have to reconstruct and none of our kids
// did either.
//
// We visit the kids first and reset their HAS_NEWLY_CONSTRUCTED_FLOW flags after checking
// them. NOTE: Make sure not to bail out early before resetting all the flags!
let mut need_to_reconstruct = false;
for kid in node.children() {
if kid.flags().contains(HAS_NEWLY_CONSTRUCTED_FLOW) {
kid.remove_flags(HAS_NEWLY_CONSTRUCTED_FLOW);
need_to_reconstruct = true
}
}
if need_to_reconstruct {
return false
}
if node.restyle_damage().contains(RECONSTRUCT_FLOW) {
return false
}
let mut style = node.style().clone();
let mut layout_data_ref = node.mutate_layout_data();
let layout_data = layout_data_ref.as_mut().expect("no layout data");
let damage = layout_data.data.restyle_damage;
match *node.construction_result_mut(layout_data) {
ConstructionResult::None => true,
ConstructionResult::Flow(ref mut flow, _) => {
// The node's flow is of the same type and has the same set of children and can
// therefore be repaired by simply propagating damage and style to the flow.
if !flow.is_block_flow() {
return false
}
let flow = flow_ref::deref_mut(flow);
flow::mut_base(flow).restyle_damage.insert(damage);
flow.repair_style_and_bubble_inline_sizes(&style);
true
}
ConstructionResult::ConstructionItem(ConstructionItem::InlineFragments(
ref mut inline_fragments_construction_result)) => {
if !inline_fragments_construction_result.splits.is_empty() {
return false
}
for fragment in inline_fragments_construction_result.fragments
.fragments
.iter_mut() {
// Only mutate the styles of fragments that represent the dirty node (including
// pseudo-element).
if fragment.node != node.opaque() {
continue
}
if fragment.pseudo != node.get_pseudo_element_type().strip() {
continue
}
match fragment.specific {
SpecificFragmentInfo::InlineBlock(ref mut inline_block_fragment) => {
let flow_ref = flow_ref::deref_mut(&mut inline_block_fragment.flow_ref);
flow::mut_base(flow_ref).restyle_damage.insert(damage);
// FIXME(pcwalton): Fragment restyle damage too?
flow_ref.repair_style_and_bubble_inline_sizes(&style);
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(
ref mut inline_absolute_hypothetical_fragment) => {
let flow_ref = flow_ref::deref_mut(
&mut inline_absolute_hypothetical_fragment.flow_ref);
flow::mut_base(flow_ref).restyle_damage.insert(damage);
// FIXME(pcwalton): Fragment restyle damage too?
flow_ref.repair_style_and_bubble_inline_sizes(&style);
}
SpecificFragmentInfo::InlineAbsolute(ref mut inline_absolute_fragment) => {
let flow_ref = flow_ref::deref_mut(
&mut inline_absolute_fragment.flow_ref);
flow::mut_base(flow_ref).restyle_damage.insert(damage);
// FIXME(pcwalton): Fragment restyle damage too?
flow_ref.repair_style_and_bubble_inline_sizes(&style);
}
SpecificFragmentInfo::ScannedText(_) => {
// Text fragments in ConstructionResult haven't been scanned yet
unreachable!()
}
SpecificFragmentInfo::GeneratedContent(_) |
SpecificFragmentInfo::UnscannedText(_) => {
// We can't repair this unscanned text; we need to update the
// scanned text fragments.
//
// TODO: Add code to find and repair the ScannedText fragments?
return false
}
_ => {
if node.is_replaced_content() {
properties::modify_style_for_replaced_content(&mut style);
}
fragment.repair_style(&style);
}
}
}
true
}
ConstructionResult::ConstructionItem(_) => {
false
}
}
}
}
impl<'a> PostorderNodeMutTraversal for FlowConstructor<'a> {
// Construct Flow based on 'display', 'position', and 'float' values.
//
// CSS 2.1 Section 9.7
//
// TODO: This should actually consult the table in that section to get the
// final computed value for 'display'.
fn process(&mut self, node: &ServoThreadSafeLayoutNode) -> bool {
// Get the `display` property for this node, and determine whether this node is floated.
let (display, float, positioning) = match node.type_id() {
None => {
// Pseudo-element.
let style = node.style();
let display = match node.get_pseudo_element_type() {
PseudoElementType::Normal => display::T::inline,
PseudoElementType::Before(display) => display,
PseudoElementType::After(display) => display,
};
(display, style.get_box().float, style.get_box().position)
}
Some(NodeTypeId::Element(_)) => {
let style = node.style();
let munged_display = if style.get_box()._servo_display_for_hypothetical_box ==
display::T::inline {
display::T::inline
} else {
style.get_box().display
};
(munged_display, style.get_box().float, style.get_box().position)
}
Some(NodeTypeId::CharacterData(CharacterDataTypeId::Text)) =>
(display::T::inline, float::T::none, position::T::static_),
Some(NodeTypeId::CharacterData(CharacterDataTypeId::Comment)) |
Some(NodeTypeId::CharacterData(CharacterDataTypeId::ProcessingInstruction)) |
Some(NodeTypeId::DocumentType) |
Some(NodeTypeId::DocumentFragment) |
Some(NodeTypeId::Document(_)) => {
(display::T::none, float::T::none, position::T::static_)
}
};
debug!("building flow for node: {:?} {:?} {:?} {:?}", display, float, positioning, node.type_id());
// Switch on display and floatedness.
match (display, float, positioning) {
// `display: none` contributes no flow construction result. Nuke the flow construction
// results of children.
(display::T::none, _, _) => {
for child in node.children() {
self.set_flow_construction_result(&child, ConstructionResult::None);
}
self.set_flow_construction_result(node, ConstructionResult::None);
}
// Table items contribute table flow construction results.
(display::T::table, float_value, _) => {
let construction_result = self.build_flow_for_table_wrapper(node, float_value);
self.set_flow_construction_result(node, construction_result)
}
// Absolutely positioned elements will have computed value of
// `float` as 'none' and `display` as per the table.
// Only match here for block items. If an item is absolutely
// positioned, but inline we shouldn't try to construct a block
// flow here - instead, let it match the inline case
// below.
(display::T::block, _, position::T::absolute) |
(display::T::block, _, position::T::fixed) => {
let construction_result = self.build_flow_for_block(node, None);
self.set_flow_construction_result(node, construction_result)
}
// List items contribute their own special flows.
(display::T::list_item, float_value, _) => {
let construction_result = self.build_flow_for_list_item(node, float_value);
self.set_flow_construction_result(node, construction_result)
}
// Inline items that are absolutely-positioned contribute inline fragment construction
// results with a hypothetical fragment.
(display::T::inline, _, position::T::absolute) => {
let construction_result =
self.build_fragment_for_absolutely_positioned_inline(node);
self.set_flow_construction_result(node, construction_result)
}
// Inline items contribute inline fragment construction results.
//
// FIXME(pcwalton, #3307): This is not sufficient to handle floated generated content.
(display::T::inline, float::T::none, _) => {
let construction_result = self.build_fragments_for_inline(node);
self.set_flow_construction_result(node, construction_result)
}
// Inline-block items contribute inline fragment construction results.
(display::T::inline_block, float::T::none, _) => {
let construction_result = self.build_fragment_for_inline_block(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_caption, _, _) => {
let construction_result = self.build_flow_for_table_caption(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_column_group, _, _) => {
let construction_result = self.build_flow_for_table_colgroup(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_column, _, _) => {
let construction_result = self.build_fragments_for_table_column(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_row_group, _, _) |
(display::T::table_header_group, _, _) |
(display::T::table_footer_group, _, _) => {
let construction_result = self.build_flow_for_table_rowgroup(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_row, _, _) => {
let construction_result = self.build_flow_for_table_row(node);
self.set_flow_construction_result(node, construction_result)
}
// Table items contribute table flow construction results.
(display::T::table_cell, _, _) => {
let construction_result = self.build_flow_for_table_cell(node);
self.set_flow_construction_result(node, construction_result)
}
// Flex items contribute flex flow construction results.
(display::T::flex, float_value, _) => {
let float_kind = FloatKind::from_property(float_value);
let construction_result = self.build_flow_for_flex(node, float_kind);
self.set_flow_construction_result(node, construction_result)
}
// Block flows that are not floated contribute block flow construction results.
//
// TODO(pcwalton): Make this only trigger for blocks and handle the other `display`
// properties separately.
(_, float_value, _) => {
let float_kind = FloatKind::from_property(float_value);
let construction_result = self.build_flow_for_block(node, float_kind);
self.set_flow_construction_result(node, construction_result)
}
}
node.insert_flags(HAS_NEWLY_CONSTRUCTED_FLOW);
true
}
}
/// A utility trait with some useful methods for node queries.
trait NodeUtils {
/// Returns true if this node doesn't render its kids and false otherwise.
fn is_replaced_content(&self) -> bool;
fn construction_result_mut(self, layout_data: &mut LayoutDataWrapper) -> &mut ConstructionResult;
/// Sets the construction result of a flow.
fn set_flow_construction_result(self, result: ConstructionResult);
/// Replaces the flow construction result in a node with `ConstructionResult::None` and returns
/// the old value.
fn swap_out_construction_result(self) -> ConstructionResult;
}
impl<'ln> NodeUtils for ServoThreadSafeLayoutNode<'ln> {
fn is_replaced_content(&self) -> bool {
match self.type_id() {
None |
Some(NodeTypeId::CharacterData(_)) |
Some(NodeTypeId::DocumentType) |
Some(NodeTypeId::DocumentFragment) |
Some(NodeTypeId::Document(_)) |
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLImageElement))) |
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLIFrameElement))) |
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLCanvasElement))) => true,
Some(NodeTypeId::Element(ElementTypeId::HTMLElement(
HTMLElementTypeId::HTMLObjectElement))) => self.has_object_data(),
Some(NodeTypeId::Element(_)) => false,
}
}
fn construction_result_mut(self, layout_data: &mut LayoutDataWrapper) -> &mut ConstructionResult {
match self.get_pseudo_element_type() {
PseudoElementType::Before(_) => &mut layout_data.data.before_flow_construction_result,
PseudoElementType::After (_) => &mut layout_data.data.after_flow_construction_result,
PseudoElementType::Normal => &mut layout_data.data.flow_construction_result,
}
}
#[inline(always)]
fn set_flow_construction_result(self, result: ConstructionResult) {
let mut layout_data_ref = self.mutate_layout_data();
let layout_data = layout_data_ref.as_mut().expect("no layout data");
let dst = self.construction_result_mut(layout_data);
*dst = result;
}
#[inline(always)]
fn swap_out_construction_result(self) -> ConstructionResult {
let mut layout_data_ref = self.mutate_layout_data();
let layout_data = layout_data_ref.as_mut().expect("no layout data");
self.construction_result_mut(layout_data).swap_out()
}
}
/// Methods for interacting with HTMLObjectElement nodes
trait ObjectElement<'a> {
/// Returns None if this node is not matching attributes.
fn get_type_and_data(&self) -> (Option<&'a str>, Option<&'a str>);
/// Returns true if this node has object data that is correct uri.
fn has_object_data(&self) -> bool;
/// Returns the "data" attribute value parsed as a URL
fn object_data(&self) -> Option<Url>;
}
impl<'ln> ObjectElement<'ln> for ServoThreadSafeLayoutNode<'ln> {
fn get_type_and_data(&self) -> (Option<&'ln str>, Option<&'ln str>) {
let elem = self.as_element();
(elem.get_attr(&ns!(), &atom!("type")), elem.get_attr(&ns!(), &atom!("data")))
}
fn has_object_data(&self) -> bool {
match self.get_type_and_data() {
(None, Some(uri)) => is_image_data(uri),
_ => false
}
}
fn object_data(&self) -> Option<Url> {
match self.get_type_and_data() {
(None, Some(uri)) if is_image_data(uri) => Url::parse(uri).ok(),
_ => None
}
}
}
// This must not be public because only the layout constructor can call these
// methods.
trait FlowConstructionUtils {
/// Adds a new flow as a child of this flow. Removes the flow from the given leaf set if
/// it's present.
fn add_new_child(&mut self, new_child: FlowRef);
/// Finishes a flow. Once a flow is finished, no more child flows or boxes may be added to it.
/// This will normally run the bubble-inline-sizes (minimum and preferred -- i.e. intrinsic --
/// inline-size) calculation, unless the global `bubble_inline-sizes_separately` flag is on.
///
/// All flows must be finished at some point, or they will not have their intrinsic inline-
/// sizes properly computed. (This is not, however, a memory safety problem.)
fn finish(&mut self);
}
impl FlowConstructionUtils for FlowRef {
/// Adds a new flow as a child of this flow. Fails if this flow is marked as a leaf.
fn add_new_child(&mut self, mut new_child: FlowRef) {
{
let kid_base = flow::mut_base(flow_ref::deref_mut(&mut new_child));
kid_base.parallel.parent = parallel::mut_owned_flow_to_unsafe_flow(self);
}
let base = flow::mut_base(flow_ref::deref_mut(self));
base.children.push_back(new_child);
let _ = base.parallel.children_count.fetch_add(1, Ordering::Relaxed);
}
/// Finishes a flow. Once a flow is finished, no more child flows or fragments may be added to
/// it. This will normally run the bubble-inline-sizes (minimum and preferred -- i.e. intrinsic
/// -- inline-size) calculation, unless the global `bubble_inline-sizes_separately` flag is on.
///
/// All flows must be finished at some point, or they will not have their intrinsic inline-sizes
/// properly computed. (This is not, however, a memory safety problem.)
fn finish(&mut self) {
if !opts::get().bubble_inline_sizes_separately {
flow_ref::deref_mut(self).bubble_inline_sizes();
flow::mut_base(flow_ref::deref_mut(self)).restyle_damage.remove(BUBBLE_ISIZES);
}
}
}
/// Strips ignorable whitespace from the start of a list of fragments.
pub fn strip_ignorable_whitespace_from_start(this: &mut LinkedList<Fragment>) {
if this.is_empty() {
return // Fast path.
}
let mut leading_fragments_consisting_of_solely_bidi_control_characters = LinkedList::new();
while !this.is_empty() {
match this.front_mut().as_mut().unwrap().strip_leading_whitespace_if_necessary() {
WhitespaceStrippingResult::RetainFragment => break,
WhitespaceStrippingResult::FragmentContainedOnlyBidiControlCharacters => {
leading_fragments_consisting_of_solely_bidi_control_characters.push_back(
this.pop_front().unwrap())
}
WhitespaceStrippingResult::FragmentContainedOnlyWhitespace => {
let removed_fragment = this.pop_front().unwrap();
if let Some(ref mut remaining_fragment) = this.front_mut() {
if let Some(ref mut inline_context_of_remaining_fragment) =
remaining_fragment.inline_context {
if let Some(ref inline_context_of_removed_fragment) =
removed_fragment.inline_context {
for (i, inline_context_node_from_removed_fragment) in
inline_context_of_removed_fragment.nodes.iter().enumerate() {
if i >= inline_context_of_remaining_fragment.nodes.len() {
break
}
if !inline_context_node_from_removed_fragment.flags.contains(
FIRST_FRAGMENT_OF_ELEMENT) {
continue
}
if inline_context_node_from_removed_fragment.address !=
inline_context_of_remaining_fragment.nodes[i].address {
continue
}
inline_context_of_remaining_fragment.nodes[i].flags.insert(
FIRST_FRAGMENT_OF_ELEMENT);
}
}
}
}
}
}
}
linked_list::prepend_from(this,
&mut leading_fragments_consisting_of_solely_bidi_control_characters);
}
/// Strips ignorable whitespace from the end of a list of fragments.
pub fn strip_ignorable_whitespace_from_end(this: &mut LinkedList<Fragment>) {
if this.is_empty() {
return
}
let mut trailing_fragments_consisting_of_solely_bidi_control_characters = LinkedList::new();
while !this.is_empty() {
match this.back_mut().as_mut().unwrap().strip_trailing_whitespace_if_necessary() {
WhitespaceStrippingResult::RetainFragment => break,
WhitespaceStrippingResult::FragmentContainedOnlyBidiControlCharacters => {
trailing_fragments_consisting_of_solely_bidi_control_characters.push_front(
this.pop_back().unwrap())
}
WhitespaceStrippingResult::FragmentContainedOnlyWhitespace => {
let removed_fragment = this.pop_back().unwrap();
if let Some(ref mut remaining_fragment) = this.back_mut() {
remaining_fragment.meld_with_next_inline_fragment(&removed_fragment);
}
}
}
}
this.append(&mut trailing_fragments_consisting_of_solely_bidi_control_characters);
}
/// If the 'unicode-bidi' property has a value other than 'normal', return the bidi control codes
/// to inject before and after the text content of the element.
fn bidi_control_chars(style: &Arc<ComputedValues>) -> Option<(&'static str, &'static str)> {
use style::computed_values::direction::T::*;
use style::computed_values::unicode_bidi::T::*;
let unicode_bidi = style.get_text().unicode_bidi;
let direction = style.get_inheritedbox().direction;
// See the table in http://dev.w3.org/csswg/css-writing-modes/#unicode-bidi
match (unicode_bidi, direction) {
(normal, _) => None,
(embed, ltr) => Some(("\u{202A}", "\u{202C}")),
(embed, rtl) => Some(("\u{202B}", "\u{202C}")),
(isolate, ltr) => Some(("\u{2066}", "\u{2069}")),
(isolate, rtl) => Some(("\u{2067}", "\u{2069}")),
(bidi_override, ltr) => Some(("\u{202D}", "\u{202C}")),
(bidi_override, rtl) => Some(("\u{202E}", "\u{202C}")),
(isolate_override, ltr) => Some(("\u{2068}\u{202D}", "\u{202C}\u{2069}")),
(isolate_override, rtl) => Some(("\u{2068}\u{202E}", "\u{202C}\u{2069}")),
(plaintext, _) => Some(("\u{2068}", "\u{2069}")),
}
}
fn control_chars_to_fragment(node: &InlineFragmentNodeInfo,
text: &str,
restyle_damage: RestyleDamage)
-> Fragment {
let info = SpecificFragmentInfo::UnscannedText(
UnscannedTextFragmentInfo::new(String::from(text), None));
let mut style = node.style.clone();
properties::modify_style_for_text(&mut style);
Fragment::from_opaque_node_and_style(node.address,
node.pseudo,
style,
restyle_damage,
info)
}
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