Cleanup

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteIndexManager.java

@@ -16,8 +16,8 @@
 
 import static com.google.firebase.firestore.util.Assert.fail;
 import static com.google.firebase.firestore.util.Assert.hardAssert;
+import static com.google.firebase.firestore.util.Util.repeatSequence;
 
-import android.text.TextUtils;
 import androidx.annotation.Nullable;
 import com.google.firebase.firestore.core.Bound;
 import com.google.firebase.firestore.core.FieldFilter;
@@ -219,17 +219,15 @@ public Set<DocumentKey> getDocumentsMatchingTarget(Target target) {
 
   /** Returns a SQL query on 'index_entries' that unions all bounds. */
   private SQLitePersistence.Query generateQuery(int indexId, Object[] bounds, String op) {
-    String[] statements = new String[bounds.length];
     Object[] bingArgs = new Object[bounds.length * 2];
     for (int i = 0; i < bounds.length; ++i) {
-      statements[i] =
-          String.format(
-              "SELECT document_name FROM index_entries WHERE index_id = ? AND index_value %s ?",
-              op);
       bingArgs[i * 2] = indexId;
       bingArgs[i * 2 + 1] = bounds[i];
     }
-    String sql = TextUtils.join(" UNION ", statements);
+    String statement =
+        String.format(
+            "SELECT document_name FROM index_entries WHERE index_id = ? AND index_value %s ?", op);
+    String sql = repeatSequence(statement, bounds.length, " UNION ");
     return db.query(sql).binding(bingArgs);
   }
 
@@ -240,22 +238,21 @@ private SQLitePersistence.Query generateQuery(
       String lowerBoundOp,
       Object[] upperBounds,
       String upperBoundOp) {
-    String[] statements = new String[lowerBounds.length * upperBounds.length];
     Object[] bingArgs = new Object[lowerBounds.length * upperBounds.length * 3];
     int i = 0;
     for (Object value1 : lowerBounds) {
       for (Object value2 : upperBounds) {
-        statements[i] =
-            String.format(
-                "SELECT document_name FROM index_entries WHERE index_id = ? AND index_value %s ? AND index_value %s ?",
-                lowerBoundOp, upperBoundOp);
         bingArgs[i * 3] = indexId;
         bingArgs[i * 3 + 1] = value1;
         bingArgs[i * 3 + 2] = value2;
         ++i;
       }
     }
-    String sql = TextUtils.join(" UNION ", statements);
+    String statement =
+        String.format(
+            "SELECT document_name FROM index_entries WHERE index_id = ? AND index_value %s ? AND index_value %s ?",
+            lowerBoundOp, upperBoundOp);
+    String sql = repeatSequence(statement, lowerBounds.length * upperBounds.length, " UNION ");
     return db.query(sql).binding(bingArgs);
   }
 

firebase-firestore/src/main/java/com/google/firebase/firestore/util/Util.java

@@ -234,4 +234,17 @@ public static int compareByteStrings(ByteString left, ByteString right) {
     }
     return Util.compareIntegers(left.size(), right.size());
   }
+
+  public static String repeatSequence(CharSequence sequence, int count, CharSequence delimiter) {
+    if (count == 0) {
+      return "";
+    }
+    final StringBuilder sb = new StringBuilder();
+    sb.append(sequence);
+    for (int i = 1; i < count; i++) {
+      sb.append(delimiter);
+      sb.append(sequence);
+    }
+    return sb.toString();
+  }
 }