Add add-on (DLC) support (#1519)

Add add-on content support

Co-authored-by: nmzik <Nmzik@mail.ru>

src/common/additionalContent.cpp

@@ -0,0 +1,112 @@
+#include "common/additionalContent.h"
+
+#include "common/stringUtils.h"
+
+#include <algorithm>
+#include <fstream>
+#include <map>
+#include <nlohmann/json.hpp>
+#include <regex>
+#include <system_error>
+
+namespace Common {
+
+namespace {
+
+std::string GetString(const nlohmann::json& object, const std::string& key) {
+	const auto it = object.find(key);
+	return it != object.end() && it->is_string() ? it->get<std::string>() : std::string {};
+}
+
+std::string GetTitle(const nlohmann::json& param) {
+	const auto localized = param.find("localizedParameters");
+	if (localized != param.end() && localized->is_object()) {
+		const auto preferred = localized->find(GetString(*localized, "defaultLanguage"));
+		if (preferred != localized->end()) {
+			if (auto title = GetString(*preferred, "titleName"); !title.empty()) {
+				return title;
+			}
+		}
+		for (const auto& language: *localized) {
+			if (auto title = GetString(language, "titleName"); !title.empty()) {
+				return title;
+			}
+		}
+	}
+	return GetString(param, "titleName");
+}
+
+} // namespace
+
+std::vector<AddContentEntry> FindAddContent(const std::filesystem::path& dir,
+                                            const std::string&           title_id) {
+	if (dir.empty() || title_id.empty()) {
+		return {};
+	}
+
+	std::error_code ec;
+	const auto      root = std::filesystem::absolute(dir, ec);
+	if (ec) {
+		return {};
+	}
+
+	// Scan directories separately so an unreadable child does not discard its siblings.
+	std::vector<std::filesystem::path> pending {root};
+	std::vector<std::filesystem::path> params;
+	while (!pending.empty()) {
+		const auto current = std::move(pending.back());
+		pending.pop_back();
+		std::filesystem::directory_iterator it(
+		    current, std::filesystem::directory_options::skip_permission_denied, ec);
+		const std::filesystem::directory_iterator end;
+		for (; !ec && it != end; it.increment(ec)) {
+			std::error_code entry_ec;
+			if (it->is_directory(entry_ec) && !it->is_symlink(entry_ec) && !entry_ec) {
+				pending.push_back(it->path());
+			} else if (it->is_regular_file(entry_ec) && !entry_ec &&
+			           EqualNoCase(PathToString(it->path().filename()), "param.json") &&
+			           EqualNoCase(PathToString(it->path().parent_path().filename()), "sce_sys")) {
+				params.push_back(it->path());
+			}
+		}
+	}
+	std::sort(params.begin(), params.end());
+
+	static const std::regex content_id_pattern(
+	    "^[A-Z]{2}[0-9]{4}-[A-Z]{4}[0-9]{5}_[0-9]{2}-[A-Z0-9]{16}$");
+	std::map<std::string, AddContentEntry> by_label;
+	for (const auto& file: params) {
+		const auto size = std::filesystem::file_size(file, ec);
+		if (ec || size > 1024 * 1024) {
+			continue;
+		}
+		std::ifstream stream(file, std::ios::binary);
+		if (!stream) {
+			continue;
+		}
+		const auto param = nlohmann::json::parse(stream, nullptr, false);
+		// applicationCategoryType is required for applications, not additional content.
+		if (!param.is_object() || param.contains("applicationCategoryType")) {
+			continue;
+		}
+		const auto content_id = GetString(param, "contentId");
+		if (!std::regex_match(content_id, content_id_pattern) ||
+		    content_id.compare(7, 9, title_id) != 0) {
+			continue;
+		}
+
+		const auto mount_dir = file.parent_path().parent_path();
+		const auto label     = content_id.substr(20);
+		by_label.try_emplace(label,
+		                     AddContentEntry {content_id, label, mount_dir, GetTitle(param)});
+	}
+
+	std::vector<AddContentEntry> entries;
+	entries.reserve(by_label.size());
+	for (auto& [label, entry]: by_label) {
+		entries.push_back(std::move(entry));
+	}
+	return entries;
+}
+
+} // namespace Common