flatpak: do not fetch updates every time we check the size of a package

It makes libflatpak (libsoup internally) go bonkers. It also makes the
whole startup much slower (understandably).
By using FlatpakRemoteRef instead of querying the FlatpakInstallation we
have the opportunity for some optimisations since we're querying the
FlatpakRemoteRef twice for some (most?) available packages.

libdiscover/backends/FlatpakBackend/FlatpakFetchDataJob.cpp

@@ -8,41 +8,32 @@
 #include "FlatpakFetchDataJob.h"
 #include "FlatpakResource.h"
 
-#include <QDebug>
-
-static FlatpakRef * createFakeRef(FlatpakResource *resource)
+namespace FlatpakRunnables
 {
-    FlatpakRef *ref = nullptr;
-    g_autoptr(GError) localError = nullptr;
 
-    const auto id = resource->ref();
-    ref = flatpak_ref_parse(id.toUtf8().constData(), &localError);
-
-    if (!ref) {
-        qWarning() << "Failed to create fake ref: " << localError->message;
+static FlatpakRemoteRef* findRemoteRef(FlatpakResource *app, GCancellable* cancellable, GError **error)
+{
+    if (app->origin().isEmpty()) {
+        qWarning() << "Failed to get metadata file because of missing origin";
+        return nullptr;
     }
 
-    return ref;
+    const auto kind = app->resourceType() == FlatpakResource::DesktopApp ? FLATPAK_REF_KIND_APP : FLATPAK_REF_KIND_RUNTIME;
+    const QByteArray origin = app->origin().toUtf8(), name = app->flatpakName().toUtf8(), arch = app->arch().toUtf8(), branch = app->branch().toUtf8();
+    return flatpak_installation_fetch_remote_ref_sync_full(app->installation(), origin.constData(), kind, name.constData(), arch.constData(), branch.constData(), FLATPAK_QUERY_FLAGS_ONLY_CACHED, cancellable, error);
 }
 
-namespace FlatpakRunnables
-{
 QByteArray fetchMetadata(FlatpakResource *app, GCancellable* cancellable)
 {
     g_autoptr(GError) localError = nullptr;
 
-    if (app->origin().isEmpty()) {
-        qWarning() << "Failed to get metadata file because of missing origin";
-        return {};
-    }
+    FlatpakRemoteRef* remote = findRemoteRef(app, cancellable, &localError);
 
-    g_autoptr(FlatpakRef) fakeRef = createFakeRef(app);
-    if (!fakeRef) {
-        return {};
-    }
+    Q_ASSERT(remote);
+    Q_ASSERT(!localError);
 
     QByteArray metadataContent;
-    g_autoptr(GBytes) data = flatpak_installation_fetch_remote_metadata_sync(app->installation(), app->origin().toUtf8().constData(), fakeRef, cancellable, &localError);
+    g_autoptr(GBytes) data = flatpak_remote_ref_get_metadata(remote);
     if (data) {
         gsize len = 0;
         auto buff = g_bytes_get_data(data, &len);
@@ -65,16 +56,14 @@ SizeInformation fetchFlatpakSize(FlatpakResource *app, GCancellable* cancellable
     g_autoptr(GError) localError = nullptr;
 
     SizeInformation ret;
-    g_autoptr(FlatpakRef) ref = createFakeRef(app);
-    if (!ref) {
-        return ret;
-    }
-
-    if (!flatpak_installation_fetch_remote_size_sync(app->installation(), app->origin().toUtf8().constData(), ref, &ret.downloadSize, &ret.installedSize, cancellable, &localError)) {
-        qWarning() << "Failed to get remote size of " << app->name() << ": " << localError->message;
+    FlatpakRemoteRef* remote = findRemoteRef(app, cancellable, &localError);
+    if (!remote) {
+        qWarning() << "Failed to get remote size of" << app->name() << app->origin() << ":" << localError->message;
         return ret;
     }
 
+    ret.downloadSize = flatpak_remote_ref_get_download_size(remote);
+    ret.installedSize = flatpak_remote_ref_get_installed_size(remote);
     ret.valid = true;
     return ret;
 }