libcamera: yaml_parser: Add getList() function

Allow to retrieve a YAML list of any already supported types in a
std::vector.

Signed-off-by: Florian Sylvestre <fsylvestre@baylibre.com>
Tested-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/internal/yaml_parser.h

@@ -183,6 +183,22 @@ public:
 		return get<T>().value_or(defaultValue);
 	}
 
+#ifndef __DOXYGEN__
+	template<typename T,
+		 typename std::enable_if_t<
+			 std::is_same_v<bool, T> ||
+			 std::is_same_v<double, T> ||
+			 std::is_same_v<int16_t, T> ||
+			 std::is_same_v<uint16_t, T> ||
+			 std::is_same_v<int32_t, T> ||
+			 std::is_same_v<uint32_t, T> ||
+			 std::is_same_v<std::string, T> ||
+			 std::is_same_v<Size, T>> * = nullptr>
+#else
+	template<typename T>
+#endif
+	std::optional<std::vector<T>> getList() const;
+
 	DictAdapter asDict() const { return DictAdapter{ list_ }; }
 	ListAdapter asList() const { return ListAdapter{ list_ }; }
 

src/libcamera/yaml_parser.cpp

@@ -292,6 +292,59 @@ std::optional<Size> YamlObject::get() const
 
 #endif /* __DOXYGEN__ */
 
+/**
+ * \fn template<typename T> YamlObject::getList<T>() const
+ * \brief Parse the YamlObject as a list of \a T
+ *
+ * This function parses the value of the YamlObject as a list of \a T objects,
+ * and returns the value as a \a std::vector<T>. If parsing fails, std::nullopt
+ * is returned.
+ *
+ * \return The YamlObject value as a std::vector<T>, or std::nullopt if parsing
+ * failed
+ */
+
+#ifndef __DOXYGEN__
+
+template<typename T,
+	 typename std::enable_if_t<
+		 std::is_same_v<bool, T> ||
+		 std::is_same_v<double, T> ||
+		 std::is_same_v<int16_t, T> ||
+		 std::is_same_v<uint16_t, T> ||
+		 std::is_same_v<int32_t, T> ||
+		 std::is_same_v<uint32_t, T> ||
+		 std::is_same_v<std::string, T> ||
+		 std::is_same_v<Size, T>> *>
+std::optional<std::vector<T>> YamlObject::getList() const
+{
+	if (type_ != Type::List)
+		return {};
+
+	std::vector<T> values;
+	values.reserve(list_.size());
+
+	for (const YamlObject &entry : asList()) {
+		const auto value = entry.get<T>();
+		if (!value)
+			return {};
+		values.emplace_back(*value);
+	}
+
+	return values;
+}
+
+template std::optional<std::vector<bool>> YamlObject::getList<bool>() const;
+template std::optional<std::vector<double>> YamlObject::getList<double>() const;
+template std::optional<std::vector<int16_t>> YamlObject::getList<int16_t>() const;
+template std::optional<std::vector<uint16_t>> YamlObject::getList<uint16_t>() const;
+template std::optional<std::vector<int32_t>> YamlObject::getList<int32_t>() const;
+template std::optional<std::vector<uint32_t>> YamlObject::getList<uint32_t>() const;
+template std::optional<std::vector<std::string>> YamlObject::getList<std::string>() const;
+template std::optional<std::vector<Size>> YamlObject::getList<Size>() const;
+
+#endif /* __DOXYGEN__ */
+
 /**
  * \fn YamlObject::asDict() const
  * \brief Wrap a dictionary YamlObject in an adapter that exposes iterators

test/yaml-parser.cpp

@@ -518,6 +518,12 @@ protected:
 			return TestFail;
 		}
 
+		const auto &values = firstElement.getList<uint16_t>();
+		if (!values || values->size() != 2 || (*values)[0] != 1 || (*values)[1] != 2) {
+			cerr << "getList() failed to return correct vector" << std::endl;
+			return TestFail;
+		}
+
 		auto &secondElement = level2Obj[1];
 		if (!secondElement.isDictionary() ||
 		    !secondElement.contains("one") ||