Only update suggested versions, not other unneeded things.

Also, while we are here, lets notify the content observers that the suggested
versions have changed, so that the UI can update in response.

app/src/main/java/org/fdroid/fdroid/FDroidApp.java

@@ -256,7 +256,7 @@ public class FDroidApp extends Application {
         Preferences.get().registerUnstableUpdatesChangeListener(new Preferences.ChangeListener() {
             @Override
             public void onPreferenceChange() {
-                AppProvider.Helper.calcDetailsFromIndex(context);
+                AppProvider.Helper.calcSuggestedApks(context);
             }
         });
 

app/src/main/java/org/fdroid/fdroid/data/AppProvider.java

@@ -170,12 +170,8 @@ public class AppProvider extends FDroidProvider {
             return app;
         }
 
-        public static void calcDetailsFromIndex(Context context) {
+        public static void calcSuggestedApks(Context context) {
-            context.getContentResolver().update(calcAllDetailsFromIndexUri(), null, null, null);
+            context.getContentResolver().update(calcSuggestedApksUri(), null, null, null);
-        }
-
-        public static void calcDetailsFromIndex(Context context) {
-            context.getContentResolver().update(calcAllDetailsFromIndexUri(), null, null, null);
         }
 
         public static List<App> findCanUpdate(Context context, String[] projection) {
@@ -428,10 +424,10 @@ public class AppProvider extends FDroidProvider {
     private static final String PATH_RECENTLY_UPDATED = "recentlyUpdated";
     private static final String PATH_NEWLY_ADDED = "newlyAdded";
     private static final String PATH_CATEGORY = "category";
-    private static final String PATH_CALC_ALL_DETAILS_FROM_INDEX = "calcDetailsFromIndex";
     private static final String PATH_REPO = "repo";
     private static final String PATH_HIGHEST_PRIORITY = "highestPriority";
     private static final String PATH_CALC_PREFERRED_METADATA = "calcPreferredMetadata";
+    private static final String PATH_CALC_SUGGESTED_APKS = "calcNonRepoDetailsFromIndex";
 
     private static final int CAN_UPDATE = CODE_SINGLE + 1;
     private static final int INSTALLED = CAN_UPDATE + 1;
@@ -440,8 +436,8 @@ public class AppProvider extends FDroidProvider {
     private static final int RECENTLY_UPDATED = NO_APKS + 1;
     private static final int NEWLY_ADDED = RECENTLY_UPDATED + 1;
     private static final int CATEGORY = NEWLY_ADDED + 1;
-    private static final int CALC_ALL_DETAILS_FROM_INDEX = CATEGORY + 1;
+    private static final int CALC_SUGGESTED_APKS = CATEGORY + 1;
-    private static final int REPO = CALC_ALL_DETAILS_FROM_INDEX + 1;
+    private static final int REPO = CALC_SUGGESTED_APKS + 1;
     private static final int SEARCH_REPO = REPO + 1;
     private static final int SEARCH_INSTALLED = SEARCH_REPO + 1;
     private static final int SEARCH_CAN_UPDATE = SEARCH_INSTALLED + 1;
@@ -450,7 +446,7 @@ public class AppProvider extends FDroidProvider {
 
     static {
         MATCHER.addURI(getAuthority(), null, CODE_LIST);
-        MATCHER.addURI(getAuthority(), PATH_CALC_ALL_DETAILS_FROM_INDEX, CALC_ALL_DETAILS_FROM_INDEX);
+        MATCHER.addURI(getAuthority(), PATH_CALC_SUGGESTED_APKS, CALC_SUGGESTED_APKS);
         MATCHER.addURI(getAuthority(), PATH_RECENTLY_UPDATED, RECENTLY_UPDATED);
         MATCHER.addURI(getAuthority(), PATH_NEWLY_ADDED, NEWLY_ADDED);
         MATCHER.addURI(getAuthority(), PATH_CATEGORY + "/*", CATEGORY);
@@ -479,8 +475,8 @@ public class AppProvider extends FDroidProvider {
         return Uri.withAppendedPath(getContentUri(), PATH_NEWLY_ADDED);
     }
 
-    private static Uri calcAllDetailsFromIndexUri() {
+    private static Uri calcSuggestedApksUri() {
-        return Uri.withAppendedPath(getContentUri(), PATH_CALC_ALL_DETAILS_FROM_INDEX);
+        return Uri.withAppendedPath(getContentUri(), PATH_CALC_SUGGESTED_APKS);
     }
 
     public static Uri getCategoryUri(String category) {
@@ -916,11 +912,12 @@ public class AppProvider extends FDroidProvider {
 
     @Override
     public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
-        if (MATCHER.match(uri) != CALC_ALL_DETAILS_FROM_INDEX) {
+        if (MATCHER.match(uri) != CALC_SUGGESTED_APKS) {
             throw new UnsupportedOperationException("Update not supported for " + uri + ".");
         }
 
-        updateAllAppDetails();
+        updateSuggestedApks();
+        getContext().getContentResolver().notifyChange(getCanUpdateUri(), null);
         return 0;
     }
 
@@ -932,6 +929,27 @@ public class AppProvider extends FDroidProvider {
         updateIconUrls();
     }
 
+    /**
+     * If the repo hasn't changed, then there are many things which we shouldn't waste time updating
+     * (compared to {@link AppProvider#updateAllAppDetails()}:
+     *
+     * + The "preferred metadata", as that is calculated based on repo with highest priority, and
+     *   only takes into account the package name, not specific versions, when figuring this out.
+     *
+     * + Compatible flags. These were calculated earlier, whether or not an app was suggested or not.
+     *
+     * + Icon URLs. While technically these do change when the suggested version changes, it is not
+     *   important enough to spend a significant amount of time to calculate. In the future maybe,
+     *   but that effort should instead go into implementing an intent service.
+     *
+     * In the future, this problem of taking a long time should be fixed by implementing an
+     * {@link android.app.IntentService} as described in https://gitlab.com/fdroid/fdroidclient/issues/520.
+     */
+    protected void updateSuggestedApks() {
+        updateSuggestedFromUpstream();
+        updateSuggestedFromLatest();
+    }
+
     private void updatePreferredMetadata() {
         Utils.debugLog(TAG, "Deciding on which metadata should take priority for each package.");