[Mesa-dev] [PATCH 7/7] wayland-egl: rework and simplify wl_egl_window initialization

[Emil Velikov]

From: Emil Velikov <emil.velikov at collabora.com>

Use calloc instead of malloc + explicitly zeroing the different fields.
We need special handling for the version field which if of type
const intptr_t.

As we're here document why keeping the constness is a good idea.

The wl_egl_window_resize() call is replaced with an explicit set of the
width/height.

Cc: Miguel A. Vico <mvicomoya at nvidia.com>
Cc: Daniel Stone <daniels at collabora.com>
Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
---
Miguel I believe the comment correctly describes the design plan, while
addressing Dan's comment that things look a bit ugly.

Dan, if you prefer I could still use malloc + c99 initializer.
I opted for this route since it provides nice place to document why
things are as they are.
---
 src/egl/wayland/wayland-egl/wayland-egl.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/egl/wayland/wayland-egl/wayland-egl.c b/src/egl/wayland/wayland-egl/wayland-egl.c
index 4501c6dc956..e7cea895ece 100644
--- a/src/egl/wayland/wayland-egl/wayland-egl.c
+++ b/src/egl/wayland/wayland-egl/wayland-egl.c
@@ -61,26 +61,32 @@ WL_EGL_EXPORT struct wl_egl_window *
 wl_egl_window_create(struct wl_surface *surface,
 		     int width, int height)
 {
-	struct wl_egl_window _INIT_ = { .version = WL_EGL_WINDOW_VERSION };
 	struct wl_egl_window *egl_window;
 
 	if (width <= 0 || height <= 0)
 		return NULL;
 
-	egl_window = malloc(sizeof *egl_window);
+	egl_window = calloc(1, sizeof *egl_window);
 	if (!egl_window)
 		return NULL;
 
-	memcpy(egl_window, &_INIT_, sizeof *egl_window);
+	/* Cast away the constness to set the version number.
+	 *
+	 * We want the const notation since it gives an explicit
+	 * feedback to the backend implementation, should it try to
+	 * change it.
+	 *
+	 * The latter in itself is not too surprising as these days APIs
+	 * tend to provide bidirectional version field.
+	 */
+	intptr_t *version = (intptr_t *)&egl_window->version;
+	*version = WL_EGL_WINDOW_VERSION;
 
 	egl_window->surface = surface;
-	egl_window->private = NULL;
-	egl_window->resize_callback = NULL;
-	egl_window->destroy_window_callback = NULL;
-	wl_egl_window_resize(egl_window, width, height, 0, 0);
-	egl_window->attached_width  = 0;
-	egl_window->attached_height = 0;
-	
+
+	egl_window->width  = width;
+	egl_window->height = height;
+
 	return egl_window;
 }
 
-- 
2.14.1