orm: Add ::count() and ::expunge() to InstrumentedList

include/class.orm.php

@@ -435,10 +435,6 @@ class ModelInstanceIterator implements Iterator, ArrayAccess {
         return $this->cache;
     }
 
-    function objects() {
-        return clone $this->queryset;
-    }
-
     // Iterator interface
     function rewind() {
         $this->position = 0;
@@ -507,23 +503,43 @@ class InstrumentedList extends ModelInstanceIterator {
             $this->resource = null;
     }
 
-    function add($object) {
+    function add($object, $at=false) {
         if (!$object || !$object instanceof $this->model)
             throw new Exception('Attempting to add invalid object to list');
 
-        $object->{$this->key} = $this->id;
+        $object->set($this->key, $this->id);
         $object->save();
-        $this->list[] = $object;
+
+        if ($at !== false)
+            $this->cache[$at] = $object;
+        else
+            $this->cache[] = $object;
     }
     function remove($object) {
         $object->delete();
     }
 
+    function reset() {
+        $this->cache = array();
+    }
+
+    // QuerySet delegates
+    function count() {
+        return $this->queryset->count();
+    }
+    function exists() {
+        return $this->queryset->exists();
+    }
+    function expunge() {
+        return $this->queryset->delete();
+    }
     function update(array $what) {
         return $this->queryset->update($what);
     }
-    function reset() {
-        $this->cache = array();
+
+    // Fetch a new QuerySet
+    function objects() {
+        return clone $this->queryset;
     }
 
     function offsetUnset($a) {
@@ -533,7 +549,7 @@ class InstrumentedList extends ModelInstanceIterator {
     function offsetSet($a, $b) {
         $this->fillTo($a);
         $this->cache[$a]->delete();
-        $this->add($b);
+        $this->add($b, $a);
     }
 }