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			103 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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 * Copyright (c) 2024, Sam Atkins <sam@ladybird.org>
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 *
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 * SPDX-License-Identifier: BSD-2-Clause
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 */
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#include "CountersSet.h"
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#include <LibWeb/DOM/Element.h>
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#include <LibWeb/DOM/Node.h>
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namespace Web::CSS {
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// https://drafts.csswg.org/css-lists-3/#instantiate-counter
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Counter& CountersSet::instantiate_a_counter(FlyString name, UniqueNodeID originating_element_id, bool reversed, Optional<CounterValue> value)
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{
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    // 1. Let counters be element’s CSS counters set.
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    auto* element = DOM::Node::from_unique_id(originating_element_id);
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    // 2. Let innermost counter be the last counter in counters with the name name.
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    //    If innermost counter’s originating element is element or a previous sibling of element,
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    //    remove innermost counter from counters.
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    auto innermost_counter = last_counter_with_name(name);
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    if (innermost_counter.has_value()) {
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        auto* originating_node = DOM::Node::from_unique_id(innermost_counter->originating_element_id);
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        VERIFY(originating_node);
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        auto& innermost_element = as<DOM::Element>(*originating_node);
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        if (&innermost_element == element
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            || (innermost_element.parent() == element->parent() && innermost_element.is_before(*element))) {
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            m_counters.remove_first_matching([&innermost_counter](auto& it) {
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                return it.name == innermost_counter->name
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                    && it.originating_element_id == innermost_counter->originating_element_id;
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            });
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        }
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    }
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    // 3. Append a new counter to counters with name name, originating element element,
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    //    reversed being reversed, and initial value value (if given)
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    m_counters.append({
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        .name = move(name),
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        .originating_element_id = originating_element_id,
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        .reversed = reversed,
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        .value = value,
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    });
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    return m_counters.last();
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}
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// https://drafts.csswg.org/css-lists-3/#propdef-counter-set
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void CountersSet::set_a_counter(FlyString name, UniqueNodeID originating_element_id, CounterValue value)
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{
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    if (auto existing_counter = last_counter_with_name(name); existing_counter.has_value()) {
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        existing_counter->value = value;
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        return;
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    }
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    // If there is not currently a counter of the given name on the element, the element instantiates
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    // a new counter of the given name with a starting value of 0 before setting or incrementing its value.
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    // https://drafts.csswg.org/css-lists-3/#valdef-counter-set-counter-name-integer
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    auto& counter = instantiate_a_counter(name, originating_element_id, false, 0);
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    counter.value = value;
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}
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// https://drafts.csswg.org/css-lists-3/#propdef-counter-increment
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void CountersSet::increment_a_counter(FlyString name, UniqueNodeID originating_element_id, CounterValue amount)
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{
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    if (auto existing_counter = last_counter_with_name(name); existing_counter.has_value()) {
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        // FIXME: How should we handle existing counters with no value? Can that happen?
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        VERIFY(existing_counter->value.has_value());
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        existing_counter->value->saturating_add(amount.value());
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        return;
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    }
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    // If there is not currently a counter of the given name on the element, the element instantiates
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    // a new counter of the given name with a starting value of 0 before setting or incrementing its value.
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    // https://drafts.csswg.org/css-lists-3/#valdef-counter-set-counter-name-integer
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    auto& counter = instantiate_a_counter(name, originating_element_id, false, 0);
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    counter.value->saturating_add(amount.value());
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}
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Optional<Counter&> CountersSet::last_counter_with_name(FlyString const& name)
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{
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    for (auto& counter : m_counters.in_reverse()) {
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        if (counter.name == name)
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            return counter;
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    }
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    return {};
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}
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Optional<Counter&> CountersSet::counter_with_same_name_and_creator(FlyString const& name, UniqueNodeID originating_element_id)
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{
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    return m_counters.first_matching([&](auto& it) {
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        return it.name == name && it.originating_element_id == originating_element_id;
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    });
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}
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void CountersSet::append_copy(Counter const& counter)
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{
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    m_counters.append(counter);
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}
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}
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