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Chad Versace authored
This rewrites the bulk of Waffle's code. When I first began writing Waffle, I wanted to experiment with a non-traditional object model that used tagged unions. Very soon I began to abhor the "innovative" decision. This patch replaces the tagged-union model with a more traditional object model (as found in the Linux kernel [1], Google's NaCl, libdrm, and many other places) that uses vtables and embedded structures. [1] Neil Brown. LWN, 2011 June 1. Object-oriented design patterns in the kernel. (Part 1: http://lwn.net/Articles/444910/). (Part 2: http://lwn.net/Articles/446317/ ). As an example of the new object model, below is an outline of how waffle_window_swap_buffers() is now implemeneted. // file: waffle_window.c bool waffle_window_swap_buffers(struct waffle_window *self) { struct wcore_window *wc_self = wcore_window(self); // safe cast // Check preconditions ... return wc_self->vtbl->swap_buffers(wc_self); } // file: wcore_window.h struct wcore_window_vtbl { bool (*swap_buffers)(struct wcore_window *self); // More member functions ... }; struct wcore_window { const struct wcore_window_vtbl *vtbl; struct waffle_window {} wfl; // More members ... }; // file: glx_window.h struct glx_window { struct wcore_window wcore; // More members ... }; // file: glx_window.c static bool glx_window_swap_buffers(struct wcore_window *wc_self) { struct glx_window *self = glx_window(wc_self); // safe cast // Call glXSwapBuffers ... return true; } static const struct wcore_window_vtbl glx_window_wcore_vtbl = { .swap_buffers = glx_window_swap_buffers, // More members ... }; Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
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