OutputConfigurationParser - Introduce OutputAction class

Author: Zainullin Damir

src/core/outputFieldConfigurationParser/outputAction.cpp

@@ -0,0 +1,126 @@
+/**
+ * @file
+ * @brief Implementation of OutputAction.
+ * @author Damir Zainullin <[email protected]>
+ *
+ * @copyright Copyright (c) 2025 CESNET, z.s.p.o.
+ */
+
+#include "outputAction.hpp"
+
+#include <algorithm>
+#include <cctype>
+#include <functional>
+#include <ranges>
+#include <stdexcept>
+#include <string>
+#include <variant>
+#include <vector>
+
+namespace ipxp {
+
+// Helper because std::isspace takes int
+constexpr static bool isSpace(const char c) noexcept
+{
+	return std::isspace(c);
+}
+
+OutputAction::OutputAction(std::string_view line)
+{
+	if (std::ranges::any_of(line, isSpace)) {
+		throw std::invalid_argument(
+			"Invalid field specification: " + std::string(line)
+			+ ". No whitespace characters are allowed.");
+	}
+
+	type = line.starts_with('-') ? Type::Exclude : Type::Include;
+	if (type == Type::Exclude) {
+		line.remove_prefix(1);
+	}
+
+	if (line.contains(".")) {
+		if (std::ranges::count(line, '.') != 1) {
+			throw std::invalid_argument(
+				"Invalid field specification: " + std::string(line)
+				+ ". Only one '.' is allowed to separate plugin and field name.");
+		}
+		const std::size_t dotPos = line.find('.');
+		action = FieldAction {
+			.pluginName = std::string(line.substr(0, dotPos)),
+			.fieldName = std::string(line.substr(dotPos + 1))};
+		return;
+	}
+
+	if (line == "*") {
+		action = GlobalAction {};
+		return;
+	}
+
+	action = PluginAction {std::string(line)};
+}
+
+constexpr static std::string_view trimFieldsHeader(std::string_view content)
+{
+	std::string_view header = "fields:";
+	if (!content.starts_with(header)) {
+		throw std::invalid_argument("Configuration file must start with \"fields:\" header");
+	}
+
+	content.remove_prefix(header.size());
+	const std::size_t firstQuotePos
+		= std::ranges::find_if(content, std::not_fn(isSpace)) - content.begin();
+	if (firstQuotePos == content.size() || content[firstQuotePos] != '\'') {
+		throw std::invalid_argument(
+			"Configuration file must contain opening quote after \"fields:\" header");
+	}
+
+	const std::size_t lastQuotePos = content.size() - 1
+		- (std::find_if(content.rbegin(), content.rend(), std::not_fn(isSpace)) - content.rbegin());
+	if (lastQuotePos == -1ULL || content[lastQuotePos] != '\'') {
+		throw std::invalid_argument(
+			"Configuration file must contain closing quote after field definitions");
+	}
+
+	return content.substr(firstQuotePos + 1, lastQuotePos - firstQuotePos - 1);
+}
+
+constexpr static std::string removeComments(std::string_view content) noexcept
+{
+	std::string result(content.begin(), content.end());
+	for (std::size_t sharpPos = result.find('#'); sharpPos != std::string::npos;
+		 sharpPos = result.find('#', sharpPos)) {
+		const std::size_t endOfLinePos = result.find('\n', sharpPos);
+		if (endOfLinePos == std::string::npos) {
+			result.erase(sharpPos);
+		} else {
+			result.erase(sharpPos, endOfLinePos - sharpPos + 1);
+		}
+	}
+
+	return result;
+}
+
+std::vector<OutputAction> parseActions(std::string_view configurationContent)
+{
+	return removeComments(trimFieldsHeader(configurationContent)) | std::views::split(',')
+		| std::views::transform([](const auto lineRange) {
+			   return std::string_view(&*lineRange.begin(), std::ranges::distance(lineRange));
+		   })
+		// Remove empty lines
+		| std::views::filter([](std::string_view line) {
+			   return std::ranges::find_if(line, std::not_fn(isSpace)) != line.end();
+		   })
+		// Trim spaces on the sides
+		| std::views::transform([](std::string_view line) {
+			   const std::size_t firstNonSpacePos
+				   = std::ranges::find_if(line, std::not_fn(isSpace)) - line.begin();
+			   const std::size_t lastNonSpacePos = line.size() - 1
+				   - (std::find_if(line.rbegin(), line.rend(), std::not_fn(isSpace))
+					  - line.rbegin());
+			   return line.substr(firstNonSpacePos, lastNonSpacePos - firstNonSpacePos + 1);
+		   })
+		| std::views::transform([](std::string_view line) { return OutputAction(line); })
+		| std::ranges::to<std::vector>();
+}
+
+} // namespace ipxp

src/core/outputFieldConfigurationParser/outputAction.hpp

@@ -0,0 +1,42 @@
+
+/**
+ * @file
+ * @brief Declaration of OutputAction.
+ * @author Damir Zainullin <[email protected]>
+ *
+ * @copyright Copyright (c) 2025 CESNET, z.s.p.o.
+ */
+
+#pragma once
+
+#include <ranges>
+#include <stdexcept>
+#include <string>
+#include <variant>
+#include <vector>
+
+namespace ipxp {
+
+struct OutputAction {
+	enum class Type : bool { Include, Exclude };
+
+	struct GlobalAction {};
+
+	struct PluginAction {
+		std::string pluginName;
+	};
+
+	struct FieldAction {
+		std::string pluginName;
+		std::string fieldName;
+	};
+
+	Type type;
+	std::variant<GlobalAction, PluginAction, FieldAction> action;
+
+	OutputAction(std::string_view line);
+};
+
+std::vector<OutputAction> parseActions(std::string_view configurationContent);
+
+} // namespace ipxp