1 #pragma once
2 
3 #include <mbgl/style/data_driven_property_value.hpp>
4 #include <mbgl/style/conversion.hpp>
5 #include <mbgl/style/conversion/constant.hpp>
6 #include <mbgl/style/conversion/function.hpp>
7 #include <mbgl/style/expression/is_expression.hpp>
8 #include <mbgl/style/expression/is_constant.hpp>
9 #include <mbgl/style/expression/literal.hpp>
10 #include <mbgl/style/expression/value.hpp>
11 #include <mbgl/style/expression/parsing_context.hpp>
12 
13 namespace mbgl {
14 namespace style {
15 namespace conversion {
16 
17 template <class T>
18 struct Converter<DataDrivenPropertyValue<T>> {
operator ()mbgl::style::conversion::Converter19     optional<DataDrivenPropertyValue<T>> operator()(const Convertible& value, Error& error, bool convertTokens) const {
20         using namespace mbgl::style::expression;
21 
22         if (isUndefined(value)) {
23             return DataDrivenPropertyValue<T>();
24         }
25 
26         optional<PropertyExpression<T>> expression;
27 
28         if (isExpression(value)) {
29             ParsingContext ctx(valueTypeToExpressionType<T>());
30             ParseResult parsed = ctx.parseLayerPropertyExpression(value);
31             if (!parsed) {
32                 error = { ctx.getCombinedErrors() };
33                 return {};
34             }
35             expression = PropertyExpression<T>(std::move(*parsed));
36         } else if (isObject(value)) {
37             expression = convertFunctionToExpression<T>(value, error, convertTokens);
38         } else {
39             optional<T> constant = convert<T>(value, error);
40             if (!constant) {
41                 return {};
42             }
43             return convertTokens ? maybeConvertTokens(*constant) : DataDrivenPropertyValue<T>(*constant);
44         }
45 
46         if (!expression) {
47             return {};
48         } else if (!(*expression).isFeatureConstant() || !(*expression).isZoomConstant()) {
49             return { std::move(*expression) };
50         } else if ((*expression).getExpression().getKind() == Kind::Literal) {
51             optional<T> constant = fromExpressionValue<T>(
52                 static_cast<const Literal&>((*expression).getExpression()).getValue());
53             if (!constant) {
54                 return {};
55             }
56             return DataDrivenPropertyValue<T>(*constant);
57         } else {
58             assert(false);
59             error = { "expected a literal expression" };
60             return {};
61         }
62     }
63 
64     template <class S>
maybeConvertTokensmbgl::style::conversion::Converter65     DataDrivenPropertyValue<T> maybeConvertTokens(const S& t) const {
66         return DataDrivenPropertyValue<T>(t);
67     };
68 
maybeConvertTokensmbgl::style::conversion::Converter69     DataDrivenPropertyValue<T> maybeConvertTokens(const std::string& t) const {
70         return hasTokens(t)
71             ? DataDrivenPropertyValue<T>(PropertyExpression<T>(convertTokenStringToExpression(t)))
72             : DataDrivenPropertyValue<T>(t);
73     }
74 };
75 
76 } // namespace conversion
77 } // namespace style
78 } // namespace mbgl
79