Dart FFI Bindings for libflatpak

This project provides Dart FFI (Foreign Function Interface) bindings for the libflatpak C library, allowing Dart and Flutter applications to directly interact with the Flatpak system to query, install, and manage applications and runtimes on Linux.

Prerequisites

C Development Tools: You must have a C compiler and development headers installed (gcc, pkg-config, etc.).

libflatpak: The libflatpak-dev or equivalent package must be installed on your development system.

Dart SDK: A recent version of the Dart SDK is required.

Setup

1. Update pubspec.yaml

Add the necessary dependencies to your project's pubspec.yaml file:

dependencies:
  ffi: ^2.1.0
dev_dependencies:
  ffigen: ^10.0.0

Then run dart pub get.

2. Generate Bindings (ffigen)

dart run ffigen --config ffigen.yaml

This will generate the required libflatpak.dart file.

Basic Usage Example: Listing Installed Apps

This example demonstrates how to load the library and use the bindings to list installed applications, linking to the core functions we discussed.

final ffi.DynamicLibrary libflatpak = ffi.DynamicLibrary.open('/usr/lib/x86_64-linux-gnu/libflatpak.so');

final bindings = FlatpakBindings(libflatpak);
final ffi.Pointer<ffi.Pointer<GError>> error = pkg_ffi.calloc<ffi.Pointer<GError>>();
final ffi.Pointer<FlatpakInstallation> installationPtr = bindings.flatpak_installation_new_system(ffi.nullptr, error);

if (installationPtr == ffi.nullptr) {
    if (error.value != ffi.nullptr) {
        print(
            'Failed to get FlatpakInstallation. GError pointer received: ${error.value}');
    } else {
        print(
            'Failed to get FlatpakInstallation, but no explicit GError was returned.');
    }
} else {
    print('Successfully created FlatpakInstallation object at address: $installationPtr');
}

Map<String, Map<String, dynamic>> data;
final ffi.Pointer<GPtrArray> installed_refs =
    bindings.flatpak_installation_list_installed_refs(
        installationPtr, ffi.nullptr, error);

if (installed_refs != ffi.nullptr) {
    final GPtrArray installedRefs = installed_refs.ref;
    final int length = installedRefs.len;
    print('Found $length installed references (apps and runtimes).');
    final ffi.Pointer<gpointer> pdataPtr = installedRefs.pdata;

    for (int i = 0; i < length; i++) {
        final ffi.Pointer<ffi.Void> refVoidPtr = pdataPtr.elementAt(i).value;

        final ffi.Pointer<FlatpakRef> refPtr = refVoidPtr.cast<FlatpakRef>();

        final ffi.Pointer<ffi.Char> namePtr =
            bindings.flatpak_ref_get_name(refPtr);

        final String appId = namePtr.cast<pkg_ffi.Utf8>().toDartString();
        print('[$i] Installed App/Runtime ID: $appId');
    }
}

pkg_ffi.calloc.free(pdataPtr);
pkg_ffi.calloc.free(refVoidPtr);
pkg_ffi.calloc.free(refPtr);
pkg_ffi.calloc.free(namePtr);
pkg_ffi.calloc.free(error);
pkg_ffi.calloc.free(installationPtr);