Version independent external apps (standalone apps) (#2145)

This pull requests adds a new type of external app to the firmware: The standalone app.

Pros:

Will work after an upgrade.
Size of image is only limited by shared heap size of M0 (application) (64kb total).
Cons:

No full access to all functions in the main firmware. One well defined (and versioned) API handles all communication.
The Pacman app was converted to be the first the the new kind.

firmware/application/ui_external_items_menu_loader.cpp

@@ -2,6 +2,7 @@
 
 #include "sd_card.hpp"
 #include "file_path.hpp"
+#include "ui_standalone_view.hpp"
 
 namespace ui {
 
@@ -10,8 +11,10 @@ namespace ui {
 // iterates over all ppma-s, and if it is runnable on the current system, it'll call the callback, and pass info.
 /* static */ void ExternalItemsMenuLoader::load_all_external_items_callback(std::function<void(AppInfoConsole&)> callback) {
     if (!callback) return;
+
     if (sd_card::status() != sd_card::Status::Mounted)
         return;
+
     for (const auto& entry : std::filesystem::directory_iterator(apps_dir, u"*.ppma")) {
         auto filePath = apps_dir / entry.path();
         File app;
@@ -43,6 +46,37 @@ namespace ui {
             .appLocation = application_information.menu_location};
         callback(info);
     }
+
+    for (const auto& entry : std::filesystem::directory_iterator(apps_dir, u"*.ppmp")) {
+        auto filePath = apps_dir / entry.path();
+        File app;
+
+        auto openError = app.open(filePath);
+        if (openError)
+            continue;
+
+        standalone_application_information_t application_information = {};
+
+        auto readResult = app.read(&application_information, sizeof(standalone_application_information_t));
+        if (!readResult)
+            continue;
+
+        if (application_information.header_version < CURRENT_STANDALONE_APPLICATION_API_VERSION)
+            continue;
+
+        // here the app is startable and good.
+        std::string appshortname = filePath.filename().string();
+        if (appshortname.size() >= 5 && appshortname.substr(appshortname.size() - 5) == ".ppmp") {
+            // Remove the ".ppmp" suffix
+            appshortname = appshortname.substr(0, appshortname.size() - 5);
+        }
+        AppInfoConsole info{
+            .appCallName = appshortname.c_str(),
+            .appFriendlyName = reinterpret_cast<char*>(&application_information.app_name[0]),
+            .appLocation = application_information.menu_location};
+
+        callback(info);
+    }
 }
 
 /* static */ std::vector<GridItem> ExternalItemsMenuLoader::load_external_items(app_location_t app_location, NavigationView& nav) {
@@ -103,6 +137,44 @@ namespace ui {
         external_apps.push_back(gridItem);
     }
 
+    for (const auto& entry : std::filesystem::directory_iterator(apps_dir, u"*.ppmp")) {
+        auto filePath = apps_dir / entry.path();
+        File app;
+
+        auto openError = app.open(filePath);
+        if (openError)
+            continue;
+
+        standalone_application_information_t application_information = {};
+
+        auto readResult = app.read(&application_information, sizeof(standalone_application_information_t));
+        if (!readResult)
+            continue;
+
+        if (application_information.menu_location != app_location)
+            continue;
+
+        if (application_information.header_version > CURRENT_STANDALONE_APPLICATION_API_VERSION)
+            continue;
+
+        GridItem gridItem = {};
+        gridItem.text = reinterpret_cast<char*>(&application_information.app_name[0]);
+
+        gridItem.color = Color((uint16_t)application_information.icon_color);
+
+        auto dyn_bmp = DynamicBitmap<16, 16>{application_information.bitmap_data};
+        gridItem.bitmap = dyn_bmp.bitmap();
+        bitmaps.push_back(std::move(dyn_bmp));
+
+        gridItem.on_select = [&nav, app_location, filePath]() {
+            if (!run_standalone_app(nav, filePath)) {
+                nav.display_modal("Error", "The .ppmp file in your " + apps_dir.string() + "\nfolder can't be read. Please\nupdate your SD Card content.");
+            }
+        };
+
+        external_apps.push_back(gridItem);
+    }
+
     return external_apps;
 }
 
@@ -187,4 +259,39 @@ namespace ui {
     return true;
 }
 
+/* static */ bool ExternalItemsMenuLoader::run_standalone_app(ui::NavigationView& nav, std::filesystem::path filePath) {
+    File app;
+
+    auto openError = app.open(filePath);
+    if (openError)
+        return false;
+
+    auto app_image = std::make_unique<uint8_t[]>(app.size());
+
+    // read file in 512 byte chunks
+    for (size_t file_read_index = 0; file_read_index < app.size(); file_read_index += std::filesystem::max_file_block_size) {
+        auto bytes_to_read = std::filesystem::max_file_block_size;
+        if (file_read_index + std::filesystem::max_file_block_size > app.size())
+            bytes_to_read = app.size() - file_read_index;
+
+        auto readResult = app.read(&app_image[file_read_index], bytes_to_read);
+        if (!readResult)
+            return false;
+
+        if (readResult.value() < std::filesystem::max_file_block_size)
+            break;
+    }
+
+    for (size_t file_read_index = 0; file_read_index < app.size() / 4; file_read_index++) {
+        uint32_t* ptr = reinterpret_cast<uint32_t*>(&app_image[file_read_index * 4]);
+
+        if (*ptr >= 0xADB10000 && *ptr < (0xADB10000 + 64 * 1024)) {
+            *ptr = *ptr - 0xADB10000 + (uint32_t)app_image.get();
+        }
+    }
+
+    nav.push<StandaloneView>(std::move(app_image));
+    return true;
+}
+
 }  // namespace ui