servo/components/layout_2020/table/construct.rs
Oriol Brufau 50f56affe3
Lint layout_2020 with clippy (#31169)
cargo clippy --fix -p layout_2020 --allow-dirty --broken-code
2024-01-25 09:03:31 +00:00

716 lines
27 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 https://mozilla.org/MPL/2.0/. */
use std::borrow::Cow;
use std::convert::{TryFrom, TryInto};
use log::warn;
use script_layout_interface::wrapper_traits::ThreadSafeLayoutNode;
use servo_arc::Arc;
use style::properties::ComputedValues;
use style::selector_parser::PseudoElement;
use style::str::char_is_whitespace;
use style::values::specified::TextDecorationLine;
use super::{Table, TableSlot, TableSlotCell, TableSlotCoordinates, TableSlotOffset};
use crate::context::LayoutContext;
use crate::dom::{BoxSlot, NodeExt};
use crate::dom_traversal::{Contents, NodeAndStyleInfo, NonReplacedContents, TraversalHandler};
use crate::flow::{BlockContainerBuilder, BlockFormattingContext};
use crate::formatting_contexts::{
IndependentFormattingContext, NonReplacedFormattingContext,
NonReplacedFormattingContextContents,
};
use crate::fragment_tree::{BaseFragmentInfo, FragmentFlags, Tag};
use crate::style_ext::{DisplayGeneratingBox, DisplayLayoutInternal};
/// A reference to a slot and its coordinates in the table
#[derive(Clone, Copy, Debug)]
pub(super) struct ResolvedSlotAndLocation<'a> {
pub cell: &'a TableSlotCell,
pub coords: TableSlotCoordinates,
}
impl<'a> ResolvedSlotAndLocation<'a> {
fn covers_cell_at(&self, coords: TableSlotCoordinates) -> bool {
let covered_in_x =
coords.x >= self.coords.x && coords.x < self.coords.x + self.cell.colspan;
let covered_in_y = coords.y >= self.coords.y &&
(self.cell.rowspan == 0 || coords.y < self.coords.y + self.cell.rowspan);
covered_in_x && covered_in_y
}
}
pub(crate) enum AnonymousTableContent<'dom, Node> {
Text(NodeAndStyleInfo<Node>, Cow<'dom, str>),
Element {
info: NodeAndStyleInfo<Node>,
display: DisplayGeneratingBox,
contents: Contents,
box_slot: BoxSlot<'dom>,
},
}
impl Table {
pub(crate) fn construct<'dom>(
context: &LayoutContext,
info: &NodeAndStyleInfo<impl NodeExt<'dom>>,
contents: NonReplacedContents,
propagated_text_decoration_line: TextDecorationLine,
) -> Self {
let mut traversal =
TableBuilderTraversal::new(context, info, propagated_text_decoration_line);
contents.traverse(context, info, &mut traversal);
traversal.finish()
}
pub(crate) fn construct_anonymous<'dom, Node>(
context: &LayoutContext,
parent_info: &NodeAndStyleInfo<Node>,
contents: Vec<AnonymousTableContent<'dom, Node>>,
propagated_text_decoration_line: style::values::specified::TextDecorationLine,
) -> IndependentFormattingContext
where
Node: crate::dom::NodeExt<'dom>,
{
let anonymous_style = context
.shared_context()
.stylist
.style_for_anonymous::<Node::ConcreteElement>(
&context.shared_context().guards,
// TODO: This should be updated for Layout 2020 once we've determined
// which styles should be inherited for tables.
&PseudoElement::ServoLegacyAnonymousTable,
&parent_info.style,
);
let anonymous_info = parent_info.new_replacing_style(anonymous_style.clone());
let mut table_builder =
TableBuilderTraversal::new(context, &anonymous_info, propagated_text_decoration_line);
for content in contents {
match content {
AnonymousTableContent::Element {
info,
display,
contents,
box_slot,
} => {
table_builder.handle_element(&info, display, contents, box_slot);
},
AnonymousTableContent::Text(..) => {
// This only happens if there was whitespace between our internal table elements.
// We only collect that whitespace in case we need to re-emit trailing whitespace
// after we've added our anonymous table.
},
}
}
IndependentFormattingContext::NonReplaced(NonReplacedFormattingContext {
base_fragment_info: (&anonymous_info).into(),
style: anonymous_style,
content_sizes: None,
contents: NonReplacedFormattingContextContents::Table(table_builder.finish()),
})
}
/// Push a new slot into the last row of this table.
fn push_new_slot_to_last_row(&mut self, slot: TableSlot) {
let last_row = match self.slots.last_mut() {
Some(row) => row,
None => {
unreachable!("Should have some rows before calling `push_new_slot_to_last_row`")
},
};
self.size.width = self.size.width.max(last_row.len() + 1);
last_row.push(slot);
}
/// Find [`ResolvedSlotAndLocation`] of all the slots that cover the slot at the given
/// coordinates. This recursively resolves all of the [`TableSlotCell`]s that cover
/// the target and returns a [`ResolvedSlotAndLocation`] for each of them. If there is
/// no slot at the given coordinates or that slot is an empty space, an empty vector
/// is returned.
pub(super) fn resolve_slot_at(
&self,
coords: TableSlotCoordinates,
) -> Vec<ResolvedSlotAndLocation<'_>> {
let slot = self.get_slot(coords);
match slot {
Some(TableSlot::Cell(cell)) => vec![ResolvedSlotAndLocation { cell, coords }],
Some(TableSlot::Spanned(ref offsets)) => offsets
.iter()
.flat_map(|offset| self.resolve_slot_at(coords - *offset))
.collect(),
Some(TableSlot::Empty) | None => {
warn!("Tried to resolve an empty or nonexistant slot!");
vec![]
},
}
}
/// Create a [`TableSlot::Spanned`] for the target cell at the given coordinates. If
/// no slots cover the target, then this returns [`None`]. Note: This does not handle
/// slots that cover the target using `colspan`, but instead only considers slots that
/// cover this slot via `rowspan`. `colspan` should be handled by appending to the
/// return value of this function.
fn create_spanned_slot_based_on_cell_above(
&self,
target_coords: TableSlotCoordinates,
) -> Option<TableSlot> {
let coords_for_slot_above =
TableSlotCoordinates::new(target_coords.x, self.slots.len() - 2);
let slots_covering_slot_above = self.resolve_slot_at(coords_for_slot_above);
let coords_of_slots_that_cover_target: Vec<_> = slots_covering_slot_above
.into_iter()
.filter(|slot| slot.covers_cell_at(target_coords))
.map(|slot| target_coords - slot.coords)
.collect();
if coords_of_slots_that_cover_target.is_empty() {
None
} else {
Some(TableSlot::Spanned(coords_of_slots_that_cover_target))
}
}
}
impl TableSlot {
/// Merge a TableSlot::Spanned(x, y) with this (only for model errors)
pub fn push_spanned(&mut self, new_offset: TableSlotOffset) {
match *self {
TableSlot::Cell { .. } => {
panic!("Should never have a table model error with an originating cell slot overlapping a spanned slot")
},
TableSlot::Spanned(ref mut vec) => vec.insert(0, new_offset),
TableSlot::Empty => {
panic!("Should never have a table model error with an empty slot");
},
}
}
}
pub struct TableBuilder {
/// The table that we are building.
table: Table,
/// An incoming rowspan is a value indicating that a cell in a row above the current row,
/// had a rowspan value other than 1. The values in this array indicate how many more
/// rows the cell should span. For example, a value of 0 at an index before `current_x()`
/// indicates that the cell on that column will not span into the next row, and at an index
/// after `current_x()` it indicates that the cell will not span into the current row.
/// A negative value means that the cell will span all remaining rows in the row group.
///
/// As each column in a row is processed, the values in this vector are updated for the
/// next row.
pub incoming_rowspans: Vec<isize>,
}
impl TableBuilder {
pub(super) fn new(style: Arc<ComputedValues>) -> Self {
Self {
table: Table::new(style),
incoming_rowspans: Vec::new(),
}
}
pub fn new_for_tests() -> Self {
Self::new(ComputedValues::initial_values().to_arc())
}
pub fn finish(mut self) -> Table {
// Make sure that every row has the same number of cells.
for row in self.table.slots.iter_mut() {
row.resize_with(self.table.size.width, || TableSlot::Empty);
}
self.table
}
fn current_y(&self) -> usize {
self.table.slots.len() - 1
}
fn current_x(&self) -> usize {
self.table.slots[self.current_y()].len()
}
fn current_coords(&self) -> TableSlotCoordinates {
TableSlotCoordinates::new(self.current_x(), self.current_y())
}
pub fn start_row(&mut self) {
self.table.slots.push(Vec::new());
self.table.size.height += 1;
self.create_slots_for_cells_above_with_rowspan(true);
}
pub fn end_row(&mut self) {
// TODO: We need to insert a cell for any leftover non-table-like
// content in the TableRowBuilder.
// Truncate entries that are zero at the end of [`Self::incoming_rowspans`]. This
// prevents padding the table with empty cells when it isn't necessary.
let current_x = self.current_x();
for i in (current_x..self.incoming_rowspans.len()).rev() {
if self.incoming_rowspans[i] == 0 {
self.incoming_rowspans.pop();
} else {
break;
}
}
self.create_slots_for_cells_above_with_rowspan(false);
}
/// When not in the process of filling a cell, make sure any incoming rowspans are
/// filled so that the next specified cell comes after them. Should have been called before
/// [`Self::handle_cell`].
///
/// if `stop_at_cell_opportunity` is set, this will stop at the first slot with
/// `incoming_rowspans` equal to zero. If not, it will insert [`TableSlot::Empty`] and
/// continue to look for more incoming rowspans (which should only be done once we're
/// finished processing the cells in a row, and after calling truncating cells with
/// remaining rowspan from the end of `incoming_rowspans`.
fn create_slots_for_cells_above_with_rowspan(&mut self, stop_at_cell_opportunity: bool) {
let mut current_x = self.current_x();
while let Some(span) = self.incoming_rowspans.get_mut(current_x) {
// This column has no incoming rowspanned cells and `stop_at_zero` is true, so
// we should stop to process new cells defined in the current row.
if *span == 0 && stop_at_cell_opportunity {
break;
}
let new_cell = if *span != 0 {
*span -= 1;
self.table
.create_spanned_slot_based_on_cell_above(self.current_coords())
.expect(
"Nonzero incoming rowspan cannot occur without a cell spanning this slot",
)
} else {
TableSlot::Empty
};
self.table.push_new_slot_to_last_row(new_cell);
current_x = self.current_x();
}
}
/// <https://html.spec.whatwg.org/multipage/#algorithm-for-processing-rows>
/// Push a single cell onto the slot map, handling any colspans it may have, and
/// setting up the outgoing rowspans.
pub fn add_cell(&mut self, cell: TableSlotCell) {
// Make sure the incoming_rowspans table is large enough
// because we will be writing to it.
let current_x = self.current_x();
let colspan = cell.colspan;
let rowspan = cell.rowspan;
if self.incoming_rowspans.len() < current_x + colspan {
self.incoming_rowspans.resize(current_x + colspan, 0isize);
}
debug_assert_eq!(
self.incoming_rowspans[current_x], 0,
"Added a cell in a position that also had an incoming rowspan!"
);
// If `rowspan` is zero, this is automatically negative and will stay negative.
let outgoing_rowspan = rowspan as isize - 1;
self.table.push_new_slot_to_last_row(TableSlot::Cell(cell));
self.incoming_rowspans[current_x] = outgoing_rowspan;
// Draw colspanned cells
for colspan_offset in 1..colspan {
let current_x_plus_colspan_offset = current_x + colspan_offset;
let new_offset = TableSlotOffset::new(colspan_offset, 0);
let incoming_rowspan = &mut self.incoming_rowspans[current_x_plus_colspan_offset];
let new_slot = if *incoming_rowspan == 0 {
*incoming_rowspan = outgoing_rowspan;
TableSlot::new_spanned(new_offset)
} else {
// This means we have a table model error.
// if `incoming_rowspan` is greater than zero, a cell from above is spanning
// into our row, colliding with the cells we are creating via colspan. In
// that case, set the incoming rowspan to the highest of two possible
// outgoing rowspan values (the incoming rowspan minus one, OR this cell's
// outgoing rowspan). `spanned_slot()`` will handle filtering out
// inapplicable spans when it needs to.
//
// If the `incoming_rowspan` is negative we are in `rowspan=0` mode, (i.e.
// rowspan=infinity), so we don't have to worry about the current cell
// making it larger. In that case, don't change the rowspan.
if *incoming_rowspan > 0 {
*incoming_rowspan = std::cmp::max(*incoming_rowspan - 1, outgoing_rowspan);
}
// This code creates a new slot in the case that there is a table model error.
let coords_of_spanned_cell =
TableSlotCoordinates::new(current_x_plus_colspan_offset, self.current_y());
match self
.table
.create_spanned_slot_based_on_cell_above(coords_of_spanned_cell)
{
Some(mut incoming_slot) => {
incoming_slot.push_spanned(new_offset);
incoming_slot
},
None => TableSlot::new_spanned(new_offset),
}
};
self.table.push_new_slot_to_last_row(new_slot);
}
debug_assert_eq!(
current_x + colspan,
self.current_x(),
"Must have produced `colspan` slot entries!"
);
self.create_slots_for_cells_above_with_rowspan(true);
}
}
pub(crate) struct TableBuilderTraversal<'style, 'dom, Node> {
context: &'style LayoutContext<'style>,
info: &'style NodeAndStyleInfo<Node>,
/// Propagated value for text-decoration-line, used to construct the block
/// contents of table cells.
propagated_text_decoration_line: TextDecorationLine,
/// The [`TableBuilder`] for this [`TableBuilderTraversal`]. This is separated
/// into another struct so that we can write unit tests against the builder.
builder: TableBuilder,
current_anonymous_row_content: Vec<AnonymousTableContent<'dom, Node>>,
}
impl<'style, 'dom, Node> TableBuilderTraversal<'style, 'dom, Node>
where
Node: NodeExt<'dom>,
{
pub(crate) fn new(
context: &'style LayoutContext<'style>,
info: &'style NodeAndStyleInfo<Node>,
propagated_text_decoration_line: TextDecorationLine,
) -> Self {
TableBuilderTraversal {
context,
info,
propagated_text_decoration_line,
builder: TableBuilder::new(info.style.clone()),
current_anonymous_row_content: Vec::new(),
}
}
pub(crate) fn finish(mut self) -> Table {
self.finish_anonymous_row_if_needed();
self.builder.finish()
}
fn finish_anonymous_row_if_needed(&mut self) {
if self.current_anonymous_row_content.is_empty() {
return;
}
let row_content = std::mem::take(&mut self.current_anonymous_row_content);
let context = self.context;
let anonymous_style = self
.context
.shared_context()
.stylist
.style_for_anonymous::<Node::ConcreteElement>(
&context.shared_context().guards,
&PseudoElement::ServoAnonymousTableCell,
&self.info.style,
);
let anonymous_info = self.info.new_replacing_style(anonymous_style);
let mut row_builder = TableRowBuilder::new(self, &anonymous_info);
for cell_content in row_content {
match cell_content {
AnonymousTableContent::Element {
info,
display,
contents,
box_slot,
} => {
row_builder.handle_element(&info, display, contents, box_slot);
},
AnonymousTableContent::Text(info, text) => {
row_builder.handle_text(&info, text);
},
}
}
row_builder.finish();
}
}
impl<'style, 'dom, Node: 'dom> TraversalHandler<'dom, Node>
for TableBuilderTraversal<'style, 'dom, Node>
where
Node: NodeExt<'dom>,
{
fn handle_text(&mut self, info: &NodeAndStyleInfo<Node>, text: Cow<'dom, str>) {
if text.chars().all(char_is_whitespace) {
return;
}
self.current_anonymous_row_content
.push(AnonymousTableContent::Text(info.clone(), text));
}
/// <https://html.spec.whatwg.org/multipage/#forming-a-table>
fn handle_element(
&mut self,
info: &NodeAndStyleInfo<Node>,
display: DisplayGeneratingBox,
contents: Contents,
box_slot: BoxSlot<'dom>,
) {
match display {
DisplayGeneratingBox::LayoutInternal(internal) => match internal {
DisplayLayoutInternal::TableRowGroup |
DisplayLayoutInternal::TableFooterGroup |
DisplayLayoutInternal::TableHeaderGroup => {
self.finish_anonymous_row_if_needed();
// TODO: Should we fixup `rowspan=0` to the actual resolved value and
// any other rowspans that have been cut short?
self.builder.incoming_rowspans.clear();
NonReplacedContents::try_from(contents).unwrap().traverse(
self.context,
info,
self,
);
// TODO: Handle style for row groups here.
// We are doing this until we have actually set a Box for this `BoxSlot`.
::std::mem::forget(box_slot)
},
DisplayLayoutInternal::TableRow => {
self.finish_anonymous_row_if_needed();
let context = self.context;
let mut row_builder = TableRowBuilder::new(self, info);
NonReplacedContents::try_from(contents).unwrap().traverse(
context,
info,
&mut row_builder,
);
row_builder.finish();
// We are doing this until we have actually set a Box for this `BoxSlot`.
::std::mem::forget(box_slot)
},
DisplayLayoutInternal::TableCaption |
DisplayLayoutInternal::TableColumn |
DisplayLayoutInternal::TableColumnGroup => {
// TODO: Handle these other types of table elements.
// We are doing this until we have actually set a Box for this `BoxSlot`.
::std::mem::forget(box_slot)
},
DisplayLayoutInternal::TableCell => {
self.current_anonymous_row_content
.push(AnonymousTableContent::Element {
info: info.clone(),
display,
contents,
box_slot,
});
},
},
_ => {
self.current_anonymous_row_content
.push(AnonymousTableContent::Element {
info: info.clone(),
display,
contents,
box_slot,
});
},
}
}
}
struct TableRowBuilder<'style, 'builder, 'dom, 'a, Node> {
table_traversal: &'builder mut TableBuilderTraversal<'style, 'dom, Node>,
/// The [`NodeAndStyleInfo`] of this table row, which we use to
/// construct anonymous table cells.
info: &'a NodeAndStyleInfo<Node>,
current_anonymous_cell_content: Vec<AnonymousTableContent<'dom, Node>>,
}
impl<'style, 'builder, 'dom, 'a, Node: 'dom> TableRowBuilder<'style, 'builder, 'dom, 'a, Node>
where
Node: NodeExt<'dom>,
{
fn new(
table_traversal: &'builder mut TableBuilderTraversal<'style, 'dom, Node>,
info: &'a NodeAndStyleInfo<Node>,
) -> Self {
table_traversal.builder.start_row();
TableRowBuilder {
table_traversal,
info,
current_anonymous_cell_content: Vec::new(),
}
}
fn finish(mut self) {
self.finish_current_anonymous_cell_if_needed();
self.table_traversal.builder.end_row();
}
fn finish_current_anonymous_cell_if_needed(&mut self) {
if self.current_anonymous_cell_content.is_empty() {
return;
}
let context = self.table_traversal.context;
let anonymous_style = context
.shared_context()
.stylist
.style_for_anonymous::<Node::ConcreteElement>(
&context.shared_context().guards,
&PseudoElement::ServoAnonymousTableCell,
&self.info.style,
);
let anonymous_info = self.info.new_replacing_style(anonymous_style);
let mut builder = BlockContainerBuilder::new(
context,
&anonymous_info,
self.table_traversal.propagated_text_decoration_line,
);
for cell_content in self.current_anonymous_cell_content.drain(..) {
match cell_content {
AnonymousTableContent::Element {
info,
display,
contents,
box_slot,
} => {
builder.handle_element(&info, display, contents, box_slot);
},
AnonymousTableContent::Text(info, text) => {
builder.handle_text(&info, text);
},
}
}
let tag = Tag::new_pseudo(
self.info.node.opaque(),
Some(PseudoElement::ServoAnonymousTableCell),
);
let base_fragment_info = BaseFragmentInfo {
tag,
flags: FragmentFlags::empty(),
};
let block_container = builder.finish();
self.table_traversal.builder.add_cell(TableSlotCell {
contents: BlockFormattingContext::from_block_container(block_container),
colspan: 1,
rowspan: 1,
style: anonymous_info.style,
base_fragment_info,
});
}
}
impl<'style, 'builder, 'dom, 'a, Node: 'dom> TraversalHandler<'dom, Node>
for TableRowBuilder<'style, 'builder, 'dom, 'a, Node>
where
Node: NodeExt<'dom>,
{
fn handle_text(&mut self, info: &NodeAndStyleInfo<Node>, text: Cow<'dom, str>) {
if text.chars().all(char_is_whitespace) {
return;
}
self.current_anonymous_cell_content
.push(AnonymousTableContent::Text(info.clone(), text));
}
/// <https://html.spec.whatwg.org/multipage/#algorithm-for-processing-rows>
fn handle_element(
&mut self,
info: &NodeAndStyleInfo<Node>,
display: DisplayGeneratingBox,
contents: Contents,
box_slot: BoxSlot<'dom>,
) {
match display {
DisplayGeneratingBox::LayoutInternal(internal) => match internal {
DisplayLayoutInternal::TableCell => {
// This value will already have filtered out rowspan=0
// in quirks mode, so we don't have to worry about that.
//
// The HTML specification limits the parsed value of `rowspan` to
// 65534 and `colspan` to 1000, so we also enforce the same limits
// when dealing with arbitrary DOM elements (perhaps created via
// script).
let node = info.node.to_threadsafe();
let rowspan = std::cmp::min(node.get_rowspan() as usize, 65534);
let colspan = std::cmp::min(node.get_colspan() as usize, 1000);
let contents = match contents.try_into() {
Ok(non_replaced_contents) => {
BlockFormattingContext::construct(
self.table_traversal.context,
info,
non_replaced_contents,
self.table_traversal.propagated_text_decoration_line,
false, /* is_list_item */
)
},
Err(_replaced) => {
unreachable!("Replaced should not have a LayoutInternal display type.");
},
};
self.finish_current_anonymous_cell_if_needed();
self.table_traversal.builder.add_cell(TableSlotCell {
contents,
colspan,
rowspan,
style: info.style.clone(),
base_fragment_info: info.into(),
});
// We are doing this until we have actually set a Box for this `BoxSlot`.
::std::mem::forget(box_slot)
},
_ => {
//// TODO: Properly handle other table-like elements in the middle of a row.
self.current_anonymous_cell_content
.push(AnonymousTableContent::Element {
info: info.clone(),
display,
contents,
box_slot,
});
},
},
_ => {
self.current_anonymous_cell_content
.push(AnonymousTableContent::Element {
info: info.clone(),
display,
contents,
box_slot,
});
},
}
}
}