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Diffstat (limited to 'src/mbgl/style/expression/compound_expression.cpp')
-rw-r--r-- | src/mbgl/style/expression/compound_expression.cpp | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/src/mbgl/style/expression/compound_expression.cpp b/src/mbgl/style/expression/compound_expression.cpp new file mode 100644 index 0000000000..c1e0639562 --- /dev/null +++ b/src/mbgl/style/expression/compound_expression.cpp @@ -0,0 +1,571 @@ +#include <mbgl/style/expression/compound_expression.hpp> +#include <mbgl/style/expression/check_subtype.hpp> +#include <mbgl/style/expression/util.hpp> +#include <mbgl/tile/geometry_tile_data.hpp> +#include <mbgl/util/ignore.hpp> + +namespace mbgl { +namespace style { +namespace expression { + +namespace detail { + +/* + The Signature<Fn> structs are wrappers around an "evaluate()" function whose + purpose is to extract the necessary Type data from the evaluate function's + type. There are three key (partial) specializations: + + Signature<R (Params...)>: + Wraps a simple evaluate function (const T0&, const T1&, ...) -> Result<U> + + Signature<R (const Varargs<T>&)>: + Wraps an evaluate function that takes an arbitrary number of arguments (via + a Varargs<T>, which is just an alias for std::vector). + + Signature<R (const EvaluationContext&, Params...)>: + Wraps an evaluate function that needs to access the expression evaluation + parameters in addition to its subexpressions, i.e., + (const EvaluationParams& const T0&, const T1&, ...) -> Result<U>. Needed + for expressions like ["zoom"], ["get", key], etc. + + In each of the above evaluate signatures, T0, T1, etc. are the types of + the successfully evaluated subexpressions. +*/ +template <class, class Enable = void> +struct Signature; + +// Simple evaluate function (const T0&, const T1&, ...) -> Result<U> +template <class R, class... Params> +struct Signature<R (Params...)> : SignatureBase { + using Args = std::array<std::unique_ptr<Expression>, sizeof...(Params)>; + + Signature(R (*evaluate_)(Params...)) : + SignatureBase( + valueTypeToExpressionType<std::decay_t<typename R::Value>>(), + std::vector<type::Type> {valueTypeToExpressionType<std::decay_t<Params>>()...} + ), + evaluate(evaluate_) + {} + + EvaluationResult apply(const EvaluationContext& evaluationParameters, const Args& args) const { + return applyImpl(evaluationParameters, args, std::index_sequence_for<Params...>{}); + } + + std::unique_ptr<Expression> makeExpression(const std::string& name, + std::vector<std::unique_ptr<Expression>> args) const override { + typename Signature::Args argsArray; + std::copy_n(std::make_move_iterator(args.begin()), sizeof...(Params), argsArray.begin()); + return std::make_unique<CompoundExpression<Signature>>(name, *this, std::move(argsArray)); + } + + R (*evaluate)(Params...); +private: + template <std::size_t ...I> + EvaluationResult applyImpl(const EvaluationContext& evaluationParameters, const Args& args, std::index_sequence<I...>) const { + const std::array<EvaluationResult, sizeof...(I)> evaluated = {{std::get<I>(args)->evaluate(evaluationParameters)...}}; + for (const auto& arg : evaluated) { + if(!arg) return arg.error(); + } + const R value = evaluate(*fromExpressionValue<std::decay_t<Params>>(*(evaluated[I]))...); + if (!value) return value.error(); + return *value; + } +}; + +// Varargs evaluate function (const Varargs<T>&) -> Result<U> +template <class R, typename T> +struct Signature<R (const Varargs<T>&)> : SignatureBase { + using Args = std::vector<std::unique_ptr<Expression>>; + + Signature(R (*evaluate_)(const Varargs<T>&)) : + SignatureBase( + valueTypeToExpressionType<std::decay_t<typename R::Value>>(), + VarargsType { valueTypeToExpressionType<T>() } + ), + evaluate(evaluate_) + {} + + std::unique_ptr<Expression> makeExpression(const std::string& name, + std::vector<std::unique_ptr<Expression>> args) const override { + return std::make_unique<CompoundExpression<Signature>>(name, *this, std::move(args)); + }; + + EvaluationResult apply(const EvaluationContext& evaluationParameters, const Args& args) const { + Varargs<T> evaluated; + evaluated.reserve(args.size()); + for (const auto& arg : args) { + const EvaluationResult evaluatedArg = arg->evaluate(evaluationParameters); + if(!evaluatedArg) return evaluatedArg.error(); + evaluated.push_back(*fromExpressionValue<std::decay_t<T>>(*evaluatedArg)); + } + const R value = evaluate(evaluated); + if (!value) return value.error(); + return *value; + } + + R (*evaluate)(const Varargs<T>&); +}; + +// Evaluate function needing parameter access, +// (const EvaluationParams&, const T0&, const T1&, ...) -> Result<U> +template <class R, class... Params> +struct Signature<R (const EvaluationContext&, Params...)> : SignatureBase { + using Args = std::array<std::unique_ptr<Expression>, sizeof...(Params)>; + + Signature(R (*evaluate_)(const EvaluationContext&, Params...)) : + SignatureBase( + valueTypeToExpressionType<std::decay_t<typename R::Value>>(), + std::vector<type::Type> {valueTypeToExpressionType<std::decay_t<Params>>()...} + ), + evaluate(evaluate_) + {} + + std::unique_ptr<Expression> makeExpression(const std::string& name, + std::vector<std::unique_ptr<Expression>> args) const override { + typename Signature::Args argsArray; + std::copy_n(std::make_move_iterator(args.begin()), sizeof...(Params), argsArray.begin()); + return std::make_unique<CompoundExpression<Signature>>(name, *this, std::move(argsArray)); + } + + EvaluationResult apply(const EvaluationContext& evaluationParameters, const Args& args) const { + return applyImpl(evaluationParameters, args, std::index_sequence_for<Params...>{}); + } + +private: + template <std::size_t ...I> + EvaluationResult applyImpl(const EvaluationContext& evaluationParameters, const Args& args, std::index_sequence<I...>) const { + const std::array<EvaluationResult, sizeof...(I)> evaluated = {{std::get<I>(args)->evaluate(evaluationParameters)...}}; + for (const auto& arg : evaluated) { + if(!arg) return arg.error(); + } + // TODO: assert correct runtime type of each arg value + const R value = evaluate(evaluationParameters, *fromExpressionValue<std::decay_t<Params>>(*(evaluated[I]))...); + if (!value) return value.error(); + return *value; + } + + R (*evaluate)(const EvaluationContext&, Params...); +}; + +// Machinery to pull out function types from class methods, lambdas, etc. +template <class R, class... Params> +struct Signature<R (*)(Params...)> + : Signature<R (Params...)> +{ using Signature<R (Params...)>::Signature; }; + +template <class T, class R, class... Params> +struct Signature<R (T::*)(Params...) const> + : Signature<R (Params...)> +{ using Signature<R (Params...)>::Signature; }; + +template <class T, class R, class... Params> +struct Signature<R (T::*)(Params...)> + : Signature<R (Params...)> +{ using Signature<R (Params...)>::Signature; }; + +template <class Lambda> +struct Signature<Lambda, std::enable_if_t<std::is_class<Lambda>::value>> + : Signature<decltype(&Lambda::operator())> +{ using Signature<decltype(&Lambda::operator())>::Signature; }; + +} // namespace detail + +using Definition = CompoundExpressionRegistry::Definition; + +template <typename T> +Result<bool> equal(const T& lhs, const T& rhs) { return lhs == rhs; } + +template <typename T> +Result<bool> notEqual(const T& lhs, const T& rhs) { return lhs != rhs; } + +template <typename Fn> +static std::unique_ptr<detail::SignatureBase> makeSignature(Fn evaluateFunction) { + return std::make_unique<detail::Signature<Fn>>(evaluateFunction); +} + +std::unordered_map<std::string, CompoundExpressionRegistry::Definition> initializeDefinitions() { + std::unordered_map<std::string, CompoundExpressionRegistry::Definition> definitions; + auto define = [&](std::string name, auto fn) { + definitions[name].push_back(makeSignature(fn)); + }; + + define("e", []() -> Result<double> { return 2.718281828459045; }); + define("pi", []() -> Result<double> { return 3.141592653589793; }); + define("ln2", []() -> Result<double> { return 0.6931471805599453; }); + + define("typeof", [](const Value& v) -> Result<std::string> { return toString(typeOf(v)); }); + + define("to-string", [](const Value& value) -> Result<std::string> { + return value.match( + [](const Color& c) -> Result<std::string> { return c.stringify(); }, // avoid quoting + [](const std::string& s) -> Result<std::string> { return s; }, // avoid quoting + [](const auto& v) -> Result<std::string> { return stringify(v); } + ); + }); + + define("to-boolean", [](const Value& v) -> Result<bool> { + return v.match( + [&] (double f) { return (bool)f; }, + [&] (const std::string& s) { return s.length() > 0; }, + [&] (bool b) { return b; }, + [&] (const NullValue&) { return false; }, + [&] (const auto&) { return true; } + ); + }); + define("to-rgba", [](const Color& color) -> Result<std::array<double, 4>> { + return std::array<double, 4> {{ color.r, color.g, color.b, color.a }}; + }); + + define("rgba", rgba); + define("rgb", [](double r, double g, double b) { return rgba(r, g, b, 1.0f); }); + + define("zoom", [](const EvaluationContext& params) -> Result<double> { + if (!params.zoom) { + return EvaluationError { + "The 'zoom' expression is unavailable in the current evaluation context." + }; + } + return *(params.zoom); + }); + + define("heatmap-density", [](const EvaluationContext& params) -> Result<double> { + if (!params.heatmapDensity) { + return EvaluationError { + "The 'heatmap-density' expression is unavailable in the current evaluation context." + }; + } + return *(params.heatmapDensity); + }); + + define("has", [](const EvaluationContext& params, const std::string& key) -> Result<bool> { + if (!params.feature) { + return EvaluationError { + "Feature data is unavailable in the current evaluation context." + }; + } + + return params.feature->getValue(key) ? true : false; + }); + define("has", [](const std::string& key, const std::unordered_map<std::string, Value>& object) -> Result<bool> { + return object.find(key) != object.end(); + }); + + define("get", [](const EvaluationContext& params, const std::string& key) -> Result<Value> { + if (!params.feature) { + return EvaluationError { + "Feature data is unavailable in the current evaluation context." + }; + } + + auto propertyValue = params.feature->getValue(key); + if (!propertyValue) { + return Null; + } + return Value(toExpressionValue(*propertyValue)); + }); + define("get", [](const std::string& key, const std::unordered_map<std::string, Value>& object) -> Result<Value> { + if (object.find(key) == object.end()) { + return Null; + } + return object.at(key); + }); + + define("length", [](const std::vector<Value>& arr) -> Result<double> { + return arr.size(); + }); + define("length", [] (const std::string s) -> Result<double> { + return s.size(); + }); + + define("properties", [](const EvaluationContext& params) -> Result<std::unordered_map<std::string, Value>> { + if (!params.feature) { + return EvaluationError { + "Feature data is unavailable in the current evaluation context." + }; + } + std::unordered_map<std::string, Value> result; + const PropertyMap properties = params.feature->getProperties(); + for (const auto& entry : properties) { + result[entry.first] = toExpressionValue(entry.second); + } + return result; + }); + + define("geometry-type", [](const EvaluationContext& params) -> Result<std::string> { + if (!params.feature) { + return EvaluationError { + "Feature data is unavailable in the current evaluation context." + }; + } + + auto type = params.feature->getType(); + if (type == FeatureType::Point) { + return "Point"; + } else if (type == FeatureType::LineString) { + return "LineString"; + } else if (type == FeatureType::Polygon) { + return "Polygon"; + } else { + return "Unknown"; + } + }); + + define("id", [](const EvaluationContext& params) -> Result<Value> { + if (!params.feature) { + return EvaluationError { + "Feature data is unavailable in the current evaluation context." + }; + } + + auto id = params.feature->getID(); + if (!id) { + return Null; + } + return id->match( + [](const auto& idValue) { + return toExpressionValue(mbgl::Value(idValue)); + } + ); + }); + + define("+", [](const Varargs<double>& args) -> Result<double> { + double sum = 0.0f; + for (auto arg : args) { + sum += arg; + } + return sum; + }); + define("-", [](double a, double b) -> Result<double> { return a - b; }); + define("-", [](double a) -> Result<double> { return -a; }); + define("*", [](const Varargs<double>& args) -> Result<double> { + double prod = 1.0f; + for (auto arg : args) { + prod *= arg; + } + return prod; + }); + define("/", [](double a, double b) -> Result<double> { return a / b; }); + define("%", [](double a, double b) -> Result<double> { return fmod(a, b); }); + define("^", [](double a, double b) -> Result<double> { return pow(a, b); }); + define("sqrt", [](double x) -> Result<double> { return sqrt(x); }); + define("log10", [](double x) -> Result<double> { return log10(x); }); + define("ln", [](double x) -> Result<double> { return log(x); }); + define("log2", [](double x) -> Result<double> { return log2(x); }); + define("sin", [](double x) -> Result<double> { return sin(x); }); + define("cos", [](double x) -> Result<double> { return cos(x); }); + define("tan", [](double x) -> Result<double> { return tan(x); }); + define("asin", [](double x) -> Result<double> { return asin(x); }); + define("acos", [](double x) -> Result<double> { return acos(x); }); + define("atan", [](double x) -> Result<double> { return atan(x); }); + + define("min", [](const Varargs<double>& args) -> Result<double> { + double result = std::numeric_limits<double>::infinity(); + for (double arg : args) { + result = fmin(arg, result); + } + return result; + }); + define("max", [](const Varargs<double>& args) -> Result<double> { + double result = -std::numeric_limits<double>::infinity(); + for (double arg : args) { + result = fmax(arg, result); + } + return result; + }); + + define("==", equal<double>); + define("==", equal<const std::string&>); + define("==", equal<bool>); + define("==", equal<NullValue>); + + define("!=", notEqual<double>); + define("!=", notEqual<const std::string&>); + define("!=", notEqual<bool>); + define("!=", notEqual<NullValue>); + + define(">", [](double lhs, double rhs) -> Result<bool> { return lhs > rhs; }); + define(">", [](const std::string& lhs, const std::string& rhs) -> Result<bool> { return lhs > rhs; }); + define(">=", [](double lhs, double rhs) -> Result<bool> { return lhs >= rhs; }); + define(">=",[](const std::string& lhs, const std::string& rhs) -> Result<bool> { return lhs >= rhs; }); + define("<", [](double lhs, double rhs) -> Result<bool> { return lhs < rhs; }); + define("<", [](const std::string& lhs, const std::string& rhs) -> Result<bool> { return lhs < rhs; }); + define("<=", [](double lhs, double rhs) -> Result<bool> { return lhs <= rhs; }); + define("<=", [](const std::string& lhs, const std::string& rhs) -> Result<bool> { return lhs <= rhs; }); + + define("!", [](bool e) -> Result<bool> { return !e; }); + + define("upcase", [](const std::string& input) -> Result<std::string> { + std::string s = input; + std::transform(s.begin(), s.end(), s.begin(), + [](unsigned char c){ return std::toupper(c); }); + return s; + }); + define("downcase", [](const std::string& input) -> Result<std::string> { + std::string s = input; + std::transform(s.begin(), s.end(), s.begin(), + [](unsigned char c){ return std::tolower(c); }); + return s; + }); + define("concat", [](const Varargs<std::string>& args) -> Result<std::string> { + std::string s; + for (const std::string& arg : args) { + s += arg; + } + return s; + }); + define("error", [](const std::string& input) -> Result<type::ErrorType> { + return EvaluationError { input }; + }); + + return definitions; +} + +std::unordered_map<std::string, Definition> CompoundExpressionRegistry::definitions = initializeDefinitions(); + +using namespace mbgl::style::conversion; +ParseResult parseCompoundExpression(const std::string name, const Convertible& value, ParsingContext& ctx) { + assert(isArray(value) && arrayLength(value) > 0); + + auto it = CompoundExpressionRegistry::definitions.find(name); + if (it == CompoundExpressionRegistry::definitions.end()) { + ctx.error( + R"(Unknown expression ")" + name + R"(". If you wanted a literal array, use ["literal", [...]].)", + 0 + ); + return ParseResult(); + } + const CompoundExpressionRegistry::Definition& definition = it->second; + + auto length = arrayLength(value); + + // Check if we have a single signature with the correct number of + // parameters. If so, then use that signature's parameter types for parsing + // (and inferring the types of) the arguments. + optional<std::size_t> singleMatchingSignature; + for (std::size_t j = 0; j < definition.size(); j++) { + const std::unique_ptr<detail::SignatureBase>& signature = definition[j]; + if ( + signature->params.is<VarargsType>() || + signature->params.get<std::vector<type::Type>>().size() == length - 1 + ) { + if (singleMatchingSignature) { + singleMatchingSignature = {}; + } else { + singleMatchingSignature = j; + } + } + } + + // parse subexpressions first + std::vector<std::unique_ptr<Expression>> args; + args.reserve(length - 1); + for (std::size_t i = 1; i < length; i++) { + optional<type::Type> expected; + + if (singleMatchingSignature) { + expected = definition[*singleMatchingSignature]->params.match( + [](const VarargsType& varargs) { return varargs.type; }, + [&](const std::vector<type::Type>& params_) { return params_[i - 1]; } + ); + } + + auto parsed = ctx.parse(arrayMember(value, i), i, expected); + if (!parsed) { + return parsed; + } + args.push_back(std::move(*parsed)); + } + return createCompoundExpression(name, definition, std::move(args), ctx); +} + + +ParseResult createCompoundExpression(const std::string& name, + std::vector<std::unique_ptr<Expression>> args, + ParsingContext& ctx) +{ + return createCompoundExpression(name, CompoundExpressionRegistry::definitions.at(name), std::move(args), ctx); +} + + +ParseResult createCompoundExpression(const std::string& name, + const Definition& definition, + std::vector<std::unique_ptr<Expression>> args, + ParsingContext& ctx) +{ + ParsingContext signatureContext(ctx.getKey()); + + for (const std::unique_ptr<detail::SignatureBase>& signature : definition) { + signatureContext.clearErrors(); + + if (signature->params.is<std::vector<type::Type>>()) { + const std::vector<type::Type>& params = signature->params.get<std::vector<type::Type>>(); + if (params.size() != args.size()) { + signatureContext.error( + "Expected " + std::to_string(params.size()) + + " arguments, but found " + std::to_string(args.size()) + " instead." + ); + continue; + } + + for (std::size_t i = 0; i < args.size(); i++) { + const std::unique_ptr<Expression>& arg = args[i]; + optional<std::string> err = type::checkSubtype(params.at(i), arg->getType()); + if (err) { + signatureContext.error(*err, i + 1); + } + } + } else if (signature->params.is<VarargsType>()) { + const type::Type& paramType = signature->params.get<VarargsType>().type; + for (std::size_t i = 0; i < args.size(); i++) { + const std::unique_ptr<Expression>& arg = args[i]; + optional<std::string> err = type::checkSubtype(paramType, arg->getType()); + if (err) { + signatureContext.error(*err, i + 1); + } + } + } + + if (signatureContext.getErrors().size() == 0) { + return ParseResult(signature->makeExpression(name, std::move(args))); + } + } + + if (definition.size() == 1) { + ctx.appendErrors(std::move(signatureContext)); + } else { + std::string signatures; + for (const auto& signature : definition) { + signatures += (signatures.size() > 0 ? " | " : ""); + signature->params.match( + [&](const VarargsType& varargs) { + signatures += "(" + toString(varargs.type) + ")"; + }, + [&](const std::vector<type::Type>& params) { + signatures += "("; + bool first = true; + for (const type::Type& param : params) { + if (!first) signatures += ", "; + signatures += toString(param); + first = false; + } + signatures += ")"; + } + ); + + } + std::string actualTypes; + for (const auto& arg : args) { + if (actualTypes.size() > 0) { + actualTypes += ", "; + } + actualTypes += toString(arg->getType()); + } + ctx.error("Expected arguments of type " + signatures + ", but found (" + actualTypes + ") instead."); + } + + return ParseResult(); +} + +} // namespace expression +} // namespace style +} // namespace mbgl |