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author | Anand Thakker <anandthakker@users.noreply.github.com> | 2017-11-08 12:34:02 -0500 |
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committer | GitHub <noreply@github.com> | 2017-11-08 12:34:02 -0500 |
commit | f648cfeef6544755fdb10c3cf8847e878d70e0ff (patch) | |
tree | 49800ebd34969b787681691f1219c6396ed58579 /src/mbgl/style/expression/literal.cpp | |
parent | 9aac976104f4c6453cf9e79e03a002565720f213 (diff) | |
download | qtlocation-mapboxgl-f648cfeef6544755fdb10c3cf8847e878d70e0ff.tar.gz |
Implement Expressions (#9439)
Ports https://github.com/mapbox/mapbox-gl-js/pull/4777 (and its several follow-ups)
Diffstat (limited to 'src/mbgl/style/expression/literal.cpp')
-rw-r--r-- | src/mbgl/style/expression/literal.cpp | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/mbgl/style/expression/literal.cpp b/src/mbgl/style/expression/literal.cpp new file mode 100644 index 0000000000..fc11878bea --- /dev/null +++ b/src/mbgl/style/expression/literal.cpp @@ -0,0 +1,108 @@ + +#include <mbgl/style/expression/literal.hpp> + +namespace mbgl { +namespace style { +namespace expression { + +template <typename T> +optional<Value> checkNumber(T n) { + if (n > std::numeric_limits<double>::max()) { + return {std::numeric_limits<double>::infinity()}; + } else { + return {static_cast<double>(n)}; + } +} + +using namespace mbgl::style::conversion; +optional<Value> parseValue(const Convertible& value, ParsingContext& ctx) { + if (isUndefined(value)) return {Null}; + if (isObject(value)) { + std::unordered_map<std::string, Value> result; + bool error = false; + eachMember(value, [&] (const std::string& k, const mbgl::style::conversion::Convertible& v) -> optional<conversion::Error> { + if (!error) { + optional<Value> memberValue = parseValue(v, ctx); + if (memberValue) { + result.emplace(k, *memberValue); + } else { + error = true; + } + } + return {}; + }); + return error ? optional<Value>() : optional<Value>(result); + } + + if (isArray(value)) { + std::vector<Value> result; + const auto length = arrayLength(value); + for(std::size_t i = 0; i < length; i++) { + optional<Value> item = parseValue(arrayMember(value, i), ctx); + if (item) { + result.emplace_back(*item); + } else { + return optional<Value>(); + } + } + return optional<Value>(result); + } + + optional<mbgl::Value> v = toValue(value); + // since value represents a JSON value, if it's not undefined, object, or + // array, it must be convertible to mbgl::Value + assert(v); + + return v->match( + [&](uint64_t n) { return checkNumber(n); }, + [&](int64_t n) { return checkNumber(n); }, + [&](double n) { return checkNumber(n); }, + [&](const auto&) { + return optional<Value>(toExpressionValue(*v)); + } + ); +} + +ParseResult Literal::parse(const Convertible& value, ParsingContext& ctx) { + if (isObject(value)) { + ctx.error(R"(Bare objects invalid. Use ["literal", {...}] instead.)"); + return ParseResult(); + } else if (isArray(value)) { + // object or array value, quoted with ["literal", value] + if (arrayLength(value) != 2) { + ctx.error("'literal' expression requires exactly one argument, but found " + std::to_string(arrayLength(value) - 1) + " instead."); + return ParseResult(); + } + const optional<Value> parsedValue = parseValue(arrayMember(value, 1), ctx); + if (!parsedValue) { + return ParseResult(); + } + + // special case: infer the item type if possible for zero-length arrays + if ( + ctx.getExpected() && + ctx.getExpected()->template is<type::Array>() && + parsedValue->template is<std::vector<Value>>() + ) { + auto type = typeOf(*parsedValue).template get<type::Array>(); + auto expected = ctx.getExpected()->template get<type::Array>(); + if ( + type.N && (*type.N == 0) && + (!expected.N || (*expected.N == 0)) + ) { + return ParseResult(std::make_unique<Literal>(expected, parsedValue->template get<std::vector<Value>>())); + } + } + + return ParseResult(std::make_unique<Literal>(*parsedValue)); + } else { + // bare primitive value (string, number, boolean, null) + const optional<Value> parsedValue = parseValue(value, ctx); + return ParseResult(std::make_unique<Literal>(*parsedValue)); + } +} + +} // namespace expression +} // namespace style +} // namespace mbgl + |