69 lines
2.1 KiB
C++
69 lines
2.1 KiB
C++
#pragma once
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#include <mbgl/util/variant.hpp>
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#include <mbgl/style/undefined.hpp>
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#include <mbgl/style/property_expression.hpp>
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namespace mbgl {
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namespace style {
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template <class T>
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class PropertyValue {
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private:
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using Value = variant<Undefined, T, PropertyExpression<T>>;
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Value value;
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friend bool operator==(const PropertyValue& lhs, const PropertyValue& rhs) { return lhs.value == rhs.value; }
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friend bool operator!=(const PropertyValue& lhs, const PropertyValue& rhs) { return !(lhs == rhs); }
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public:
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PropertyValue() = default;
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PropertyValue(T constant)
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: value(std::move(constant)) {}
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PropertyValue(PropertyExpression<T> expression)
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: value(std::move(expression)) {}
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bool isUndefined() const { return value.template is<Undefined>(); }
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bool isConstant() const { return value.template is<T>(); }
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bool isExpression() const { return value.template is<PropertyExpression<T>>(); }
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bool isDataDriven() const {
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return value.match([](const Undefined&) { return false; },
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[](const T&) { return false; },
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[](const PropertyExpression<T>& fn) { return !fn.isFeatureConstant(); });
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}
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bool isZoomConstant() const {
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return value.match([](const Undefined&) { return true; },
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[](const T&) { return true; },
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[](const PropertyExpression<T>& fn) { return fn.isZoomConstant(); });
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}
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const T& asConstant() const { return value.template get<T>(); }
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const PropertyExpression<T>& asExpression() const { return value.template get<PropertyExpression<T>>(); }
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template <class... Ts>
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auto match(Ts&&... ts) const {
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return value.match(std::forward<Ts>(ts)...);
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}
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template <typename Evaluator>
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auto evaluate(const Evaluator& evaluator, TimePoint = {}) const {
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return Value::visit(value, evaluator);
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}
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bool hasDataDrivenPropertyDifference(const PropertyValue<T>& other) const {
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return *this != other && (isDataDriven() || other.isDataDriven());
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}
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};
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} // namespace style
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} // namespace mbgl
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