92 lines
2.3 KiB
C++
92 lines
2.3 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<
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Undefined,
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T,
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PropertyExpression<T>>;
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Value value;
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friend bool operator==(const PropertyValue& lhs,
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const PropertyValue& rhs) {
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return lhs.value == rhs.value;
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}
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friend bool operator!=(const PropertyValue& lhs,
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const PropertyValue& rhs) {
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return !(lhs == rhs);
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}
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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 {
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return value.template is<Undefined>();
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}
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bool isConstant() const {
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return value.template is<T>();
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}
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bool isExpression() const {
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return value.template is<PropertyExpression<T>>();
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}
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bool isDataDriven() const {
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return value.match(
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[] (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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}
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bool isZoomConstant() const {
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return value.match(
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[] (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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}
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const T& asConstant() const {
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return value.template get<T>();
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}
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const PropertyExpression<T>& asExpression() const {
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return value.template get<PropertyExpression<T>>();
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}
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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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