Added query for 'top X apps in category' and associated test

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

@@ -378,6 +378,7 @@ public class AppProvider extends FDroidProvider {
     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 String PATH_TOP_FROM_CATEGORY = "topFromCategory";
 
     private static final int CAN_UPDATE = CODE_SINGLE + 1;
     private static final int INSTALLED = CAN_UPDATE + 1;
@@ -392,6 +393,7 @@ public class AppProvider extends FDroidProvider {
     private static final int SEARCH_CAN_UPDATE = SEARCH_INSTALLED + 1;
     private static final int HIGHEST_PRIORITY = SEARCH_CAN_UPDATE + 1;
     private static final int CALC_PREFERRED_METADATA = HIGHEST_PRIORITY + 1;
+    private static final int TOP_FROM_CATEGORY = CALC_PREFERRED_METADATA + 1;
 
     static {
         MATCHER.addURI(getAuthority(), null, CODE_LIST);
@@ -409,6 +411,7 @@ public class AppProvider extends FDroidProvider {
         MATCHER.addURI(getAuthority(), PATH_HIGHEST_PRIORITY + "/*", HIGHEST_PRIORITY);
         MATCHER.addURI(getAuthority(), PATH_SPECIFIC_APP + "/#/*", CODE_SINGLE);
         MATCHER.addURI(getAuthority(), PATH_CALC_PREFERRED_METADATA, CALC_PREFERRED_METADATA);
+        MATCHER.addURI(getAuthority(), PATH_TOP_FROM_CATEGORY + "/#/*", TOP_FROM_CATEGORY);
     }
 
     public static Uri getContentUri() {
@@ -434,6 +437,14 @@ public class AppProvider extends FDroidProvider {
                 .build();
     }
 
+    public static Uri getTopFromCategoryUri(String category, int limit) {
+        return getContentUri().buildUpon()
+                .appendPath(PATH_TOP_FROM_CATEGORY)
+                .appendPath(Integer.toString(limit))
+                .appendPath(category)
+                .build();
+    }
+
     public static Uri getInstalledUri() {
         return Uri.withAppendedPath(getContentUri(), PATH_INSTALLED);
     }
@@ -702,6 +713,8 @@ public class AppProvider extends FDroidProvider {
         // querying from.
         boolean repoIsKnown = false;
 
+        int limit = 0;
+
         switch (MATCHER.match(uri)) {
             case CALC_PREFERRED_METADATA:
                 updatePreferredMetadata();
@@ -761,6 +774,13 @@ public class AppProvider extends FDroidProvider {
                 includeSwap = false;
                 break;
 
+            case TOP_FROM_CATEGORY:
+                List<String> parts = uri.getPathSegments();
+                selection = selection.add(queryCategory(parts.get(2)));
+                limit = Integer.parseInt(parts.get(1));
+                includeSwap = false;
+                break;
+
             case RECENTLY_UPDATED:
                 sortOrder = getTableName() + "." + Cols.LAST_UPDATED + " DESC";
                 selection = selection.add(queryRecentlyUpdated());
@@ -787,14 +807,14 @@ public class AppProvider extends FDroidProvider {
             selection = selection.add(queryHighestPriority());
         }
 
-        return runQuery(uri, selection, projection, includeSwap, sortOrder);
+        return runQuery(uri, selection, projection, includeSwap, sortOrder, limit);
     }
 
     /**
      * Helper method used by both the genuine {@link AppProvider} and the temporary version used
      * by the repo updater ({@link TempAppProvider}).
      */
-    protected Cursor runQuery(Uri uri, AppQuerySelection selection, String[] projection, boolean includeSwap, String sortOrder) {
+    protected Cursor runQuery(Uri uri, AppQuerySelection selection, String[] projection, boolean includeSwap, String sortOrder, int limit) {
         if (!includeSwap) {
             selection = selection.add(queryExcludeSwap());
         }
@@ -807,6 +827,7 @@ public class AppProvider extends FDroidProvider {
         query.addSelection(selection);
         query.addFields(projection); // TODO: Make the order of addFields/addSelection not dependent on each other...
         query.addOrderBy(sortOrder);
+        query.addLimit(limit);
 
         Cursor cursor = LoggingQuery.query(db(), query.toString(), query.getArgs());
         cursor.setNotificationUri(getContext().getContentResolver(), uri);

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

@@ -14,6 +14,7 @@ abstract class QueryBuilder {
     private String selection;
     private String[] selectionArgs;
     private final List<OrderClause> orderBys = new ArrayList<>();
+    private int limit = 0;
 
     protected abstract String getRequiredTables();
 
@@ -88,6 +89,10 @@ abstract class QueryBuilder {
         }
     }
 
+    public void addLimit(int limit) {
+        this.limit = limit;
+    }
+
     public String[] getArgs() {
         List<String> args = new ArrayList<>();
 
@@ -156,7 +161,11 @@ abstract class QueryBuilder {
         return tables.toString();
     }
 
+    private String limitSql() {
+        return limit > 0 ? " LIMIT " + limit : "";
+    }
+
     public String toString() {
-        return "SELECT " + distinctSql() + fieldsSql() + " FROM " + tablesSql() + whereSql() + groupBySql() + orderBySql();
+        return "SELECT " + distinctSql() + fieldsSql() + " FROM " + tablesSql() + whereSql() + groupBySql() + orderBySql() + limitSql();
     }
 }

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

@@ -196,7 +196,7 @@ public class TempAppProvider extends AppProvider {
                 break;
         }
 
-        return super.runQuery(uri, selection, projection, true, sortOrder);
+        return super.runQuery(uri, selection, projection, true, sortOrder, 0);
     }
 
     private void ensureTempTableDetached(SQLiteDatabase db) {

app/src/test/java/org/fdroid/fdroid/data/CategoryProviderTest.java

@@ -88,6 +88,40 @@ public class CategoryProviderTest extends FDroidProviderTest {
         AppProviderTest.assertContainsOnlyIds(apps, expectedPackages);
     }
 
+    @Test
+    public void topAppsFromCategory() {
+        insertAppWithCategory("com.dog", "Dog", "Animal");
+        insertAppWithCategory("com.cat", "Cat", "Animal");
+        insertAppWithCategory("com.bird", "Bird", "Animal");
+        insertAppWithCategory("com.snake", "Snake", "Animal");
+        insertAppWithCategory("com.rat", "Rat", "Animal");
+
+        insertAppWithCategory("com.rock", "Rock", "Mineral");
+        insertAppWithCategory("com.stone", "Stone", "Mineral");
+        insertAppWithCategory("com.boulder", "Boulder", "Mineral");
+
+        insertAppWithCategory("com.banana", "Banana", "Vegetable");
+        insertAppWithCategory("com.tomato", "Tomato", "Vegetable");
+
+        assertContainsOnly(topAppsFromCategory("Animal", 3), new String[] {"com.bird", "com.cat", "com.dog", });
+        assertContainsOnly(topAppsFromCategory("Animal", 2), new String[] {"com.bird", "com.cat", });
+        assertContainsOnly(topAppsFromCategory("Animal", 1), new String[] {"com.bird", });
+
+        assertContainsOnly(topAppsFromCategory("Mineral", 2), new String[] {"com.boulder", "com.rock", });
+
+        assertContainsOnly(topAppsFromCategory("Vegetable", 10), new String[] {"com.banana", "com.tomato", });
+    }
+
+    public String[] topAppsFromCategory(String category, int numToGet) {
+        List<App> apps = AppProvider.Helper.cursorToList(contentResolver.query(AppProvider.getTopFromCategoryUri(category, numToGet), Cols.ALL, null, null, Cols.NAME));
+        String[] packageNames = new String[apps.size()];
+        for (int i = 0; i < apps.size(); i++) {
+            packageNames[i] = apps.get(i).packageName;
+        }
+
+        return packageNames;
+    }
+
     @Test
     public void testCategoriesSingle() {
         insertAppWithCategory("com.dog", "Dog", "Animal");