xcb: Wrap xcb callings in macros

... to improve readability and reliability.

This change introduces macros Q_XCB_REPLY and Q_XCB_REPLY_UNCHECKED
that allow to replace couples of xcb cookie/reply callings by
a single "calling" of a macro. The macros wrap the reply in
std::unique_ptr thus preventing the need to free it manually.

The following C++11 features are used:
  - variadic macros
  - std::unique_ptr
  - auto type deduction

Change-Id: Icf9b93353404a39bf5f4a4562b9234db18cac696
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

1 files changed, 10 insertions, 27 deletions

diff --git a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
index 725288633a..cc05671580 100644
--- a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
+++ b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
@@ -121,28 +121,19 @@ xcb_window_t QXcbNativeInterface::locateSystemTray(xcb_connection_t *conn, const
 {
     if (m_sysTraySelectionAtom == XCB_ATOM_NONE) {
         const QByteArray net_sys_tray = QString::fromLatin1("_NET_SYSTEM_TRAY_S%1").arg(screen->screenNumber()).toLatin1();
-        xcb_intern_atom_cookie_t intern_c =
-            xcb_intern_atom_unchecked(conn, true, net_sys_tray.length(), net_sys_tray);
-
-        xcb_intern_atom_reply_t *intern_r = xcb_intern_atom_reply(conn, intern_c, 0);
-
+        auto intern_r = Q_XCB_REPLY_UNCHECKED(xcb_intern_atom, conn,
+                                              true, net_sys_tray.length(), net_sys_tray);
         if (!intern_r)
             return XCB_WINDOW_NONE;
 
         m_sysTraySelectionAtom = intern_r->atom;
-        free(intern_r);
     }
 
-    xcb_get_selection_owner_cookie_t sel_owner_c = xcb_get_selection_owner_unchecked(conn, m_sysTraySelectionAtom);
-    xcb_get_selection_owner_reply_t *sel_owner_r = xcb_get_selection_owner_reply(conn, sel_owner_c, 0);
-
+    auto sel_owner_r = Q_XCB_REPLY_UNCHECKED(xcb_get_selection_owner, conn, m_sysTraySelectionAtom);
     if (!sel_owner_r)
         return XCB_WINDOW_NONE;
 
-    xcb_window_t selection_window = sel_owner_r->owner;
-    free(sel_owner_r);
-
-    return selection_window;
+    return sel_owner_r->owner;
 }
 
 bool QXcbNativeInterface::systrayVisualHasAlphaChannel()
@@ -457,21 +448,13 @@ void *QXcbNativeInterface::atspiBus()
     QXcbConnection *defaultConnection = integration->defaultConnection();
     if (defaultConnection) {
         xcb_atom_t atspiBusAtom = defaultConnection->internAtom("AT_SPI_BUS");
-        xcb_get_property_cookie_t cookie = Q_XCB_CALL2(xcb_get_property(
-                                                           defaultConnection->xcb_connection(),
-                                                           false, defaultConnection->rootWindow(),
-                                                           atspiBusAtom, XCB_ATOM_STRING, 0, 128),
-                                                       defaultConnection);
-        xcb_get_property_reply_t *reply = Q_XCB_CALL2(xcb_get_property_reply(
-                                                          defaultConnection->xcb_connection(),
-                                                          cookie, 0),
-                                                      defaultConnection);
+        auto reply = Q_XCB_REPLY(xcb_get_property, defaultConnection->xcb_connection(),
+                                     false, defaultConnection->rootWindow(),
+                                     atspiBusAtom, XCB_ATOM_STRING, 0, 128);
         Q_ASSERT(!reply->bytes_after);
-        char *data = (char *)xcb_get_property_value(reply);
-        int length = xcb_get_property_value_length(reply);
-        QByteArray *busAddress = new QByteArray(data, length);
-        free(reply);
-        return busAddress;
+        char *data = (char *)xcb_get_property_value(reply.get());
+        int length = xcb_get_property_value_length(reply.get());
+        return new QByteArray(data, length);
     }
     return 0;
 }