Begin work on icons

Signed-off-by: Slendi <slendi@socopon.com>

src/IconRegistry.cpp

@@ -0,0 +1,60 @@
+#include "IconRegistry.hpp"
+
+#include <cstdlib>
+#include <filesystem>
+#include <ranges>
+#include <stdexcept>
+
+IconTheme::IconTheme(std::filesystem::path const &themes_directory_path)
+{
+	for (auto const &dir :
+	    std::filesystem::directory_iterator(themes_directory_path)) {
+		if (!dir.is_directory())
+			continue;
+
+		auto const index_path = dir.path() / "index.theme";
+		if (std::filesystem::is_regular_file(index_path))
+			continue;
+	}
+}
+
+IconRegistry::IconRegistry()
+{
+	std::vector<std::filesystem::path> theme_directory_paths;
+
+	{
+		auto const *env { getenv("HOME") };
+		if (env && *env) {
+			theme_directory_paths.push_back(
+			    std::filesystem::path(env) / ".icons");
+		}
+	}
+
+	{
+		auto const *env { getenv("XDG_DATA_DIRS") };
+		if (env && *env) {
+			theme_directory_paths.push_back(
+			    std::filesystem::path(env) / "icons");
+		}
+	}
+
+	{
+		std::filesystem::path const path { "/usr/share/pixmaps" };
+		if (std::filesystem::exists(path))
+			theme_directory_paths.push_back(path);
+	}
+
+	for (auto const &path : std::move(theme_directory_paths)
+	        | std::views::filter([](std::filesystem::path &path) {
+		          return std::filesystem::is_directory(path);
+	          })) {
+		try {
+			m_themes.push_back({ path });
+		} catch (...) {
+		}
+	}
+
+	if (m_themes.empty()) {
+		throw std::runtime_error("Could not find any icon themes.");
+	}
+}

src/IconRegistry.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <filesystem>
+#include <unordered_map>
+#include <vector>
+
+struct Icon { };
+
+struct IconTheme {
+	IconTheme(std::filesystem::path const &themes_directory_path);
+	~IconTheme() = default;
+
+private:
+	std::unordered_map<std::string, Icon> m_cached_icons;
+};
+
+struct IconRegistry {
+	IconRegistry();
+	~IconRegistry() = default;
+
+private:
+	std::vector<IconTheme> m_themes;
+};