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, 7 insertions, 23 deletions

diff --git a/src/plugins/platforms/xcb/qxcbimage.cpp b/src/plugins/platforms/xcb/qxcbimage.cpp
index d4bdb6c771..67a959d8a4 100644
--- a/src/plugins/platforms/xcb/qxcbimage.cpp
+++ b/src/plugins/platforms/xcb/qxcbimage.cpp
@@ -91,19 +91,14 @@ QPixmap qt_xcb_pixmapFromXPixmap(QXcbConnection *connection, xcb_pixmap_t pixmap
 {
     xcb_connection_t *conn = connection->xcb_connection();
 
-    xcb_get_image_cookie_t get_image_cookie =
-        xcb_get_image_unchecked(conn, XCB_IMAGE_FORMAT_Z_PIXMAP, pixmap,
-                      0, 0, width, height, 0xffffffff);
-
-    xcb_get_image_reply_t *image_reply =
-        xcb_get_image_reply(conn, get_image_cookie, NULL);
-
+    auto image_reply = Q_XCB_REPLY_UNCHECKED(xcb_get_image, conn, XCB_IMAGE_FORMAT_Z_PIXMAP, pixmap,
+                                             0, 0, width, height, 0xffffffff);
     if (!image_reply) {
         return QPixmap();
     }
 
-    uint8_t *data = xcb_get_image_data(image_reply);
-    uint32_t length = xcb_get_image_data_length(image_reply);
+    uint8_t *data = xcb_get_image_data(image_reply.get());
+    uint32_t length = xcb_get_image_data_length(image_reply.get());
 
     QPixmap result;
 
@@ -165,7 +160,6 @@ QPixmap qt_xcb_pixmapFromXPixmap(QXcbConnection *connection, xcb_pixmap_t pixmap
         result = QPixmap::fromImage(image.copy());
     }
 
-    free(image_reply);
     return result;
 }
 
@@ -203,22 +197,15 @@ xcb_cursor_t qt_xcb_createCursorXRender(QXcbScreen *screen, const QImage &image,
     xcb_connection_t *conn = screen->xcb_connection();
     const int w = image.width();
     const int h = image.height();
-    xcb_generic_error_t *error = 0;
-    xcb_render_query_pict_formats_cookie_t formatsCookie = xcb_render_query_pict_formats(conn);
-    xcb_render_query_pict_formats_reply_t *formatsReply = xcb_render_query_pict_formats_reply(conn,
-                                                                                              formatsCookie,
-                                                                                              &error);
-    if (!formatsReply || error) {
+    auto formats = Q_XCB_REPLY(xcb_render_query_pict_formats, conn);
+    if (!formats) {
         qWarning("qt_xcb_createCursorXRender: query_pict_formats failed");
-        free(formatsReply);
-        free(error);
         return XCB_NONE;
     }
-    xcb_render_pictforminfo_t *fmt = xcb_render_util_find_standard_format(formatsReply,
+    xcb_render_pictforminfo_t *fmt = xcb_render_util_find_standard_format(formats.get(),
                                                                           XCB_PICT_STANDARD_ARGB_32);
     if (!fmt) {
         qWarning("qt_xcb_createCursorXRender: Failed to find format PICT_STANDARD_ARGB_32");
-        free(formatsReply);
         return XCB_NONE;
     }
 
@@ -230,14 +217,12 @@ xcb_cursor_t qt_xcb_createCursorXRender(QXcbScreen *screen, const QImage &image,
                                        0, 0, 0);
     if (!xi) {
         qWarning("qt_xcb_createCursorXRender: xcb_image_create failed");
-        free(formatsReply);
         return XCB_NONE;
     }
     xi->data = (uint8_t *) malloc(xi->stride * h);
     if (!xi->data) {
         qWarning("qt_xcb_createCursorXRender: Failed to malloc() image data");
         xcb_image_destroy(xi);
-        free(formatsReply);
         return XCB_NONE;
     }
     memcpy(xi->data, img.constBits(), img.byteCount());
@@ -260,7 +245,6 @@ xcb_cursor_t qt_xcb_createCursorXRender(QXcbScreen *screen, const QImage &image,
     xcb_image_destroy(xi);
     xcb_render_free_picture(conn, pic);
     xcb_free_pixmap(conn, pix);
-    free(formatsReply);
     return cursor;
 
 #else