Fix paid features unlocking in beta builds

Paid features inherited from the official app were not properly
unlocked when the VPN was started by the Android system

Fixes #255

app/src/main/java/com/emanuelef/remote_capture/Billing.java

@@ -42,12 +42,14 @@ import java.security.spec.X509EncodedKeySpec;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /* Billing stub */
 public class Billing {
     private static final String TAG = "Billing";
     private static final String KEY = "ME4wEAYHKoZIzj0CAQYFK4EEACEDOgAE6cS1N1P0kaiuxq0g70OVVE0uIOD+t809" +
             "Etg3k2h11k8uNvfkx3mL1HTjQyzSfdueyY4DqTW7+sk=";
+    private static final String PEER_SKU_KEY = "peer_skus";
 
     // SKUs
     public static final String SUPPORTER_SKU = "pcapdroid_supporter";
@@ -79,6 +81,11 @@ public class Billing {
     protected Billing(Context ctx) {
         mContext = ctx;
         mPrefs = PreferenceManager.getDefaultSharedPreferences(ctx);
+
+        // Load peer skus
+        Set<String> peer_skus = mPrefs.getStringSet(PEER_SKU_KEY, null);
+        if(peer_skus != null)
+            mPeerSkus.addAll(peer_skus);
     }
 
     public static Billing newInstance(Context ctx) {
@@ -198,7 +205,21 @@ public class Billing {
             return !Prefs.isRootCaptureEnabled(mPrefs);
     }
 
-    public void addPeerSku(String sku) {
-        mPeerSkus.add(sku);
+    public void handlePeerSkus(Set<String> skus) {
+        if(skus.equals(mPeerSkus))
+            return; // nothing changed
+
+        mPeerSkus.clear();
+        mPeerSkus.addAll(skus);
+
+        Log.i(TAG, "Peer skus updated: " + skus);
+
+        mPrefs.edit()
+                .putStringSet(PEER_SKU_KEY, mPeerSkus)
+                .apply();
+    }
+
+    public void clearPeerSkus() {
+        handlePeerSkus(new HashSet<>());
     }
 }

app/src/main/java/com/emanuelef/remote_capture/activities/MainActivity.java

@@ -318,12 +318,14 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
         AppDescriptor peer = AppsResolver.resolve(getPackageManager(), peerAppPackage, 0);
         if(peer == null) {
             Log.d(TAG, "Peer app not found");
+            mIab.clearPeerSkus();
             return;
         }
 
         PackageInfo pInfo = peer.getPackageInfo();
         if((pInfo == null) || (PackageInfoCompat.getLongVersionCode(pInfo) < 56)) {
             Log.d(TAG, "Unsupported peer app version found");
+            mIab.clearPeerSkus();
             return;
         }
 
@@ -331,6 +333,7 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
         Utils.BuildType buildType = Utils.getVerifiedBuild(this, peerAppPackage);
         if((buildType != Utils.BuildType.FDROID) && (buildType != Utils.BuildType.PLAYSTORE) && (buildType != Utils.BuildType.GITHUB)) {
             Log.d(TAG, "Unsupported peer app build: " + buildType.name());
+            mIab.clearPeerSkus();
             return;
         }
 
@@ -343,6 +346,7 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
             peerInfoLauncher.launch(intent);
         } catch (ActivityNotFoundException e) {
             Log.d(TAG, "Peer app launch failed");
+            mIab.clearPeerSkus();
         }
     }
 
@@ -357,10 +361,7 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
                 if(skus != null) {
                     Log.d(TAG, "Found peer app info");
 
-                    for(String sku: skus) {
-                        Log.d(TAG, "Peer sku: " + sku);
-                        mIab.addPeerSku(sku);
-                    }
+                    mIab.handlePeerSkus(skus);
 
                     // success
                     return;
@@ -370,6 +371,7 @@ public class MainActivity extends BaseActivity implements NavigationView.OnNavig
 
         // fail
         Log.d(TAG, "Invalid peer app result");
+        mIab.clearPeerSkus();
     }
 
     private static class MainStateAdapter extends FragmentStateAdapter {