xmllite/writer: Handle empty prefix and uri correctly in WriteStartElement().

dlls/xmllite/tests/writer.c

@@ -1736,9 +1736,33 @@ static void test_WriteFullEndElement(void)
         "<a>\r\n"
         "  <a></a>\r\n"
         "</a>");
+    IStream_Release(stream);
 
-    IXmlWriter_Release(writer);
+    /* Empty strings for prefix and uri. */
+    stream = writer_set_output(writer);
+
+    hr = IXmlWriter_SetProperty(writer, XmlWriterProperty_Indent, FALSE);
+    ok(hr == S_OK, "Failed to set property, hr %#lx.\n", hr);
+
+    hr = IXmlWriter_WriteStartElement(writer, L"", L"a", NULL);
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    hr = IXmlWriter_WriteStartElement(writer, NULL, L"b", L"");
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    hr = IXmlWriter_WriteStartElement(writer, L"", L"c", L"");
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    hr = IXmlWriter_WriteFullEndElement(writer);
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    hr = IXmlWriter_WriteFullEndElement(writer);
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    hr = IXmlWriter_WriteFullEndElement(writer);
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+
+    hr = IXmlWriter_Flush(writer);
+    ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
+    CHECK_OUTPUT(stream, "<a><b><c></c></b></a>");
     IStream_Release(stream);
+
+    IXmlWriter_Release(writer);
 }
 
 static void test_WriteCharEntity(void)

dlls/xmllite/writer.c

@@ -168,6 +168,11 @@ static inline void writer_free(const xmlwriter *writer, void *mem)
     m_free(writer->imalloc, mem);
 }
 
+static BOOL is_empty_string(const WCHAR *str)
+{
+    return !str || !*str;
+}
+
 static struct element *alloc_element(xmlwriter *writer, const WCHAR *prefix, const WCHAR *local)
 {
     struct element *ret;
@@ -176,7 +181,7 @@ static struct element *alloc_element(xmlwriter *writer, const WCHAR *prefix, con
     ret = writer_alloc(writer, sizeof(*ret));
     if (!ret) return ret;
 
-    len = prefix ? lstrlenW(prefix) + 1 /* ':' */ : 0;
+    len = is_empty_string(prefix) ? 0 : lstrlenW(prefix) + 1 /* ':' */;
     len += lstrlenW(local);
 
     ret->qname = writer_alloc(writer, (len + 1)*sizeof(WCHAR));
@@ -188,13 +193,13 @@ static struct element *alloc_element(xmlwriter *writer, const WCHAR *prefix, con
     }
 
     ret->len = len;
-    if (prefix)
+    if (is_empty_string(prefix))
+        ret->qname[0] = 0;
+    else
     {
         lstrcpyW(ret->qname, prefix);
         lstrcatW(ret->qname, L":");
     }
-    else
-        ret->qname[0] = 0;
     lstrcatW(ret->qname, local);
     list_init(&ret->ns);
 
@@ -288,11 +293,6 @@ static struct ns *writer_push_ns(xmlwriter *writer, const WCHAR *prefix, int pre
     return ns;
 }
 
-static BOOL is_empty_string(const WCHAR *str)
-{
-    return !str || !*str;
-}
-
 static struct ns *writer_find_ns_current(const xmlwriter *writer, const WCHAR *prefix, const WCHAR *uri)
 {
     struct element *element;
@@ -1676,7 +1676,7 @@ static HRESULT WINAPI xmlwriter_WriteStartElement(IXmlWriter *iface, LPCWSTR pre
 
     writer_push_element(This, element);
 
-    if (!ns && uri)
+    if (!ns && !is_empty_string(uri))
         writer_push_ns(This, prefix, prefix_len, uri);
 
     write_output_buffer_char(This->output, '<');