Added nsISimpleEnumerator as Phase I of the great enumerator unification. Added misc files for XPConnect. Details in RDF_19990422_BRANCH.

git-svn-id: svn://10.0.0.236/trunk@29015 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/xpcom/src/nsEmptyEnumerator.cpp

@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specific language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+
+/*
+
+  An empty enumerator.
+
+ */
+
+#include "nsIEnumerator.h"
+
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+
+////////////////////////////////////////////////////////////////////////
+
+class EmptyEnumeratorImpl : public nsISimpleEnumerator
+{
+public:
+    EmptyEnumeratorImpl(void) {};
+    virtual ~EmptyEnumeratorImpl(void) {};
+
+    // nsISupports interface
+    NS_IMETHOD_(nsrefcnt) AddRef(void) {
+        return 2;
+    }
+
+    NS_IMETHOD_(nsrefcnt) Release(void) {
+        return 1;
+    }
+
+    NS_IMETHOD QueryInterface(REFNSIID iid, void** result) {
+        if (! result)
+            return NS_ERROR_NULL_POINTER;
+
+        if (iid.Equals(nsISimpleEnumerator::GetIID()) ||
+            iid.Equals(kISupportsIID)) {
+            *result = (nsISimpleEnumerator*) this;
+            NS_ADDREF(this);
+            return NS_OK;
+        }
+        return NS_NOINTERFACE;
+    }
+
+    // nsISimpleEnumerator
+    NS_IMETHOD HasMoreElements(PRBool* aResult) {
+        *aResult = PR_FALSE;
+        return NS_OK;
+    }
+
+    NS_IMETHOD GetNext(nsISupports** aResult) {
+        return NS_ERROR_UNEXPECTED;
+    }
+};
+
+extern "C" NS_COM nsresult
+NS_NewEmptyEnumerator(nsISimpleEnumerator** aResult)
+{
+    static EmptyEnumeratorImpl gEmptyEnumerator;
+    *aResult = &gEmptyEnumerator;
+    return NS_OK;
+}
+