add size to tuple result to allow looping over the contents

Author: Stephen Clayton

ffi/src/lib.rs

@@ -1666,6 +1666,14 @@ pub unsafe extern "C" fn typed_value_value_type_kw(typed_value: *mut Binding) ->
     string_to_c_char(value.clone())
 }
 
+/// Returns the size of a `row` as usize
+#[no_mangle]
+pub unsafe extern "C" fn typed_value_list_size(values: *mut Vec<Binding>) -> c_int {
+    assert_not_null!(values);
+    let values = &*values;
+    values.len () as c_int
+}
+
 /// Returns the value at the provided `index` as a `Vec<ValueType>`.
 /// If there is no value present at the `index`, a null pointer is returned.
 ///

sdks/android/Mentat/library/src/main/java/org/mozilla/mentat/JNA.java

@@ -158,6 +158,7 @@ class EntityBuilder extends PointerType {}
     int typed_value_value_type(TypedValue value);
     Pointer typed_value_value_type_kw(TypedValue value);
 
+    int typed_value_list_size(TypedValueList rows);
     TypedValueList row_at_index(RelResult rows, int index);
     RelResultIter typed_value_result_set_into_iter(RelResult rows);
     TypedValueList typed_value_result_set_iter_next(RelResultIter iter);

sdks/android/Mentat/library/src/main/java/org/mozilla/mentat/TupleResult.java

@@ -37,8 +37,11 @@
  */
 public class TupleResult extends RustObject<JNA.TypedValueList> {
 
+    private int size;
+
     public TupleResult(JNA.TypedValueList pointer) {
         super(pointer);
+        this.size = JNA.INSTANCE.typed_value_list_size(super.validPointer());
     }
 
     /**
@@ -145,6 +148,14 @@ public UUID asUUID(Integer index) {
                 JNA.INSTANCE.value_at_index_into_uuid(this.validPointer(), index));
     }
 
+    /**
+     * Return the size of the tuple.
+     * @return The number of items in this tuple
+     */
+    public int size () {
+      return this.size;
+    }
+
     @Override
     protected void destroyPointer(JNA.TypedValueList p) {
         JNA.INSTANCE.typed_value_list_destroy(p);