feat(libkernel): add app metadata reading module

.gitignore

@@ -28,6 +28,7 @@
 *.out
 *.app
 
+_SaveData/
 build/
 b/
 Build/

core/libs/prx/libSceVideoOut/src/DisplayWindow.cpp

@@ -1,5 +1,6 @@
 #include "prx/libSceVideoOut/include/DisplayWindow.hpp"
 #include "prx/libSceAgcDriver/Execution/include/AspectFit.hpp"
+#include "prx/libkernel/AppMetadata/include/AppMetadata.hpp"
 #include "SDL_vulkan.h"
 #include <stdexcept>
 #include <string>
@@ -42,7 +43,8 @@ void DisplayWindow::create(std::uint32_t sourceWidth, std::uint32_t sourceHeight
         initialWidth = fitted.width;
         initialHeight = fitted.height;
     }
-    window = SDL_CreateWindow("PS5", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, static_cast<int>(initialWidth), static_cast<int>(initialHeight), SDL_WINDOW_SHOWN | SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
+    const auto title = GetAppTitle_nid_postfix();
+    window = SDL_CreateWindow(title.value, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, static_cast<int>(initialWidth), static_cast<int>(initialHeight), SDL_WINDOW_SHOWN | SDL_WINDOW_VULKAN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
     require(window != nullptr, SDL_GetError());
     SDL_SetWindowMinimumSize(window, static_cast<int>(DisplayWindowMinimumWidth), static_cast<int>(DisplayWindowMinimumHeight));
     installSubclass();

core/libs/prx/libkernel/AppMetadata/include/AppMetadata.hpp

@@ -0,0 +1,28 @@
+#ifndef CORE_LIBS_PRX_LIBKERNEL_APPMETADATA_INCLUDE_APPMETADATA_HPP
+#define CORE_LIBS_PRX_LIBKERNEL_APPMETADATA_INCLUDE_APPMETADATA_HPP
+
+#include <cstdint>
+
+struct AppTitle {
+    char value[128];
+};
+
+struct AppTitleId {
+    char value[12];
+};
+
+struct AppIconData {
+    const std::uint8_t* bytes;
+    std::uint64_t size;
+};
+
+extern "C" {
+
+AppTitle GetAppTitle_nid_postfix();
+AppTitleId GetAppTitleId_nid_postfix();
+bool HasAppIcon_nid_postfix();
+AppIconData GetAppIconData_nid_postfix();
+
+}
+
+#endif

core/libs/prx/libkernel/AppMetadata/src/AppMetadata.cpp

@@ -0,0 +1,98 @@
+#include "prx/libkernel/AppMetadata/include/AppMetadata.hpp"
+#include "prx/libc/include/General.hpp"
+
+#include <cstdint>
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace {
+
+bool g_titleLoaded = false;
+bool g_iconAttempted = false;
+bool g_iconLoaded = false;
+char g_title[128] = {};
+char g_titleId[12] = {};
+std::vector<std::uint8_t> g_iconBytes;
+
+constexpr const char* AppMetadataParamJsonGuestPath = "/app0/sce_sys/param.json";
+constexpr const char* AppMetadataIconGuestPath = "/app0/sce_sys/icon0.png";
+
+struct ParsedParamJson {
+    std::string title;
+    std::string titleId;
+};
+
+ParsedParamJson parseParamJson(const std::filesystem::path& paramJsonPath) {
+    static_cast<void>(paramJsonPath);
+    throw std::runtime_error("param.json parsing is not implemented");
+}
+
+void copyToFixedBuffer(char* destination, std::size_t destinationSize, const std::string& source) {
+    if (source.empty()) throw std::runtime_error("source string is empty");
+    if (source.size() + 1 > destinationSize) throw std::length_error("source string does not fit into destination buffer");
+    std::memcpy(destination, source.c_str(), source.size() + 1);
+}
+
+void ensureTitleLoaded() {
+    if (g_titleLoaded) return;
+    const auto resolvedPath = ResolvePath_nid_no_patch(AppMetadataParamJsonGuestPath);
+    if (!std::filesystem::exists(resolvedPath)) throw std::runtime_error("param.json not found");
+    const auto parsed = parseParamJson(resolvedPath);
+    copyToFixedBuffer(g_title, sizeof(g_title), parsed.title);
+    copyToFixedBuffer(g_titleId, sizeof(g_titleId), parsed.titleId);
+    g_titleLoaded = true;
+}
+
+void ensureIconLoaded() {
+    if (g_iconAttempted) return;
+    g_iconAttempted = true;
+    const auto resolvedPath = ResolvePath_nid_no_patch(AppMetadataIconGuestPath);
+    if (!std::filesystem::exists(resolvedPath)) return;
+    std::ifstream file(resolvedPath, std::ios::binary);
+    if (!file.is_open()) throw std::runtime_error("failed to open icon0.png");
+    file.seekg(0, std::ios::end);
+    const auto fileSize = file.tellg();
+    file.seekg(0, std::ios::beg);
+    std::vector<std::uint8_t> bytes(static_cast<std::size_t>(fileSize));
+    if (!bytes.empty()) file.read(reinterpret_cast<char*>(bytes.data()), static_cast<std::streamsize>(bytes.size()));
+    if (bytes.empty()) throw std::runtime_error("icon0.png is empty");
+    constexpr std::uint8_t PngSignature[8] = {0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A};
+    if (bytes.size() < 8 || std::memcmp(bytes.data(), PngSignature, sizeof(PngSignature)) != 0) throw std::runtime_error("icon0.png is not a valid PNG file");
+    g_iconBytes = std::move(bytes);
+    g_iconLoaded = true;
+}
+
+}
+
+extern "C" {
+
+AppTitle GetAppTitle_nid_postfix() {
+    ensureTitleLoaded();
+    AppTitle result{};
+    std::memcpy(result.value, g_title, sizeof(result.value));
+    return result;
+}
+
+AppTitleId GetAppTitleId_nid_postfix() {
+    ensureTitleLoaded();
+    AppTitleId result{};
+    std::memcpy(result.value, g_titleId, sizeof(result.value));
+    return result;
+}
+
+bool HasAppIcon_nid_postfix() {
+    ensureIconLoaded();
+    return g_iconLoaded;
+}
+
+AppIconData GetAppIconData_nid_postfix() {
+    ensureIconLoaded();
+    if (!g_iconLoaded) throw std::runtime_error("icon not available");
+    return AppIconData{ g_iconBytes.data(), g_iconBytes.size() };
+}
+
+}

core/libs/prx/libkernel/CMakeLists.txt

@@ -33,6 +33,7 @@ add_library(libkernel SHARED EXCLUDE_FROM_ALL
         ${CMAKE_CURRENT_SOURCE_DIR}/System/src/Rtld.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/System/src/Process.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/Time/Time.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/AppMetadata/src/AppMetadata.cpp
 )
 
 target_include_directories(libkernel PRIVATE ${LIBS_INCLUDE_DIR})