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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/core/css/style_scope.h"
#include "third_party/blink/renderer/core/css/parser/css_selector_parser.h"
#include "third_party/blink/renderer/core/css/properties/css_parsing_utils.h"
#include "third_party/blink/renderer/core/css/style_rule.h"
#include "third_party/blink/renderer/core/css/style_sheet_contents.h"
#include "third_party/blink/renderer/core/dom/element.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
namespace blink {
StyleScope::StyleScope(StyleRule* from, CSSSelectorList* to)
: from_(from), to_(to) {}
StyleScope::StyleScope(StyleSheetContents* contents, CSSSelectorList* to)
: contents_(contents), to_(to) {}
StyleScope::StyleScope(const StyleScope& other)
: contents_(other.contents_),
from_(other.from_ ? other.from_->Copy() : nullptr),
to_(other.to_ ? other.to_->Copy() : nullptr),
parent_(other.parent_) {}
StyleScope* StyleScope::CopyWithParent(const StyleScope* parent) const {
StyleScope* copy = MakeGarbageCollected<StyleScope>(*this);
copy->parent_ = parent;
return copy;
}
const StyleScope* StyleScope::Renest(StyleRule* new_parent) const {
StyleRule* reparented_from =
from_ ? blink::To<StyleRule>(from_->Renest(new_parent)) : nullptr;
if (from_ == reparented_from) {
return this;
}
// Note that for the "to" selector, any '&' selectors must point
// to the "from" selector.
CSSSelectorList* reparented_to = to_ ? to_->Renest(reparented_from) : nullptr;
// For implicit scopes, we should have exited early due to from_==nullptr.
CHECK(!contents_);
// The `parent_` member should only be populated via calls to CopyWithParent
// (RuleSet-time), and this StyleScope should not be one such copy.
CHECK(!parent_);
return MakeGarbageCollected<StyleScope>(reparented_from, reparented_to);
}
const CSSSelector* StyleScope::From() const {
if (from_) {
return from_->FirstSelector();
}
return nullptr;
}
const CSSSelector* StyleScope::To() const {
if (to_) {
return to_->First();
}
return nullptr;
}
StyleScope* StyleScope::Parse(CSSParserTokenStream& stream,
const CSSParserContext* context,
CSSNestingType nesting_type,
StyleRule* parent_rule_for_nesting,
StyleSheetContents* style_sheet) {
HeapVector<CSSSelector> arena;
base::span<CSSSelector> from;
base::span<CSSSelector> to;
stream.ConsumeWhitespace();
// <scope-start>
if (stream.Peek().GetType() == kLeftParenthesisToken) {
CSSParserTokenStream::BlockGuard guard(stream);
stream.ConsumeWhitespace();
from = CSSSelectorParser::ParseScopeBoundary(stream, context, nesting_type,
parent_rule_for_nesting,
style_sheet, arena);
if (from.empty()) {
return nullptr;
}
}
stream.ConsumeWhitespace();
StyleRule* from_rule = nullptr;
if (!from.empty()) {
auto* properties = ImmutableCSSPropertyValueSet::Create(
base::span<CSSPropertyValue>(), CSSParserMode::kHTMLStandardMode);
from_rule = StyleRule::Create(from, properties);
}
// to (<scope-end>)
if (css_parsing_utils::ConsumeIfIdent(stream, "to")) {
if (stream.Peek().GetType() != kLeftParenthesisToken) {
return nullptr;
}
// Note that <scope-start> should act as the enclosing style rule for
// the purposes of matching the parent pseudo-class (&) within <scope-end>,
// hence we're not passing `nesting_type` or `parent_rule_for_nesting`
// to `ParseScopeBoundary` here.
//
// https://drafts.csswg.org/css-nesting-1/#nesting-at-scope
CSSParserTokenStream::BlockGuard guard(stream);
stream.ConsumeWhitespace();
to = CSSSelectorParser::ParseScopeBoundary(
stream, context, CSSNestingType::kScope,
/* parent_rule_for_nesting */ from_rule, style_sheet, arena);
if (to.empty()) {
return nullptr;
}
}
stream.ConsumeWhitespace();
CSSSelectorList* to_list =
!to.empty() ? CSSSelectorList::AdoptSelectorVector(to) : nullptr;
if (from.empty()) {
// Implicitly rooted.
return MakeGarbageCollected<StyleScope>(style_sheet, to_list);
}
return MakeGarbageCollected<StyleScope>(from_rule, to_list);
}
void StyleScope::Trace(blink::Visitor* visitor) const {
visitor->Trace(contents_);
visitor->Trace(from_);
visitor->Trace(to_);
visitor->Trace(parent_);
}
} // namespace blink
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