[Mesa-dev] [PATCH] egl: fix for multiple window surfaces per single window

[Pielech, Adrian]

Current implementation of eglCreateWindowSurface() is against to the EGL specification, because it allows creating multiple surfaces per single window.


---
 src/egl/main/eglapi.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
index fbb14f1..3eb9fb6 100644
--- a/src/egl/main/eglapi.c
+++ b/src/egl/main/eglapi.c
@@ -102,6 +102,96 @@
 #include "eglsync.h"
 #include "eglstring.h"
 
+/**
+  * Bi direction linked list item structure for carrying window and surface fields.
+  */
+struct _window_list_item
+{
+    struct _window_list_item *prev;
+    struct _window_list_item *next;
+    EGLNativeWindowType native_window;
+    EGLSurface attached_surface;
+};
+
+typedef struct _window_list_item window_list_item;
+
+struct _window_list_item *window_surface_association_list_head = NULL;
+struct _window_list_item *window_surface_association_list_tail = NULL;
+
+static inline bool _isWindowAssociatedWithSurface(EGLNativeWindowType window)
+{
+    struct _window_list_item *it = window_surface_association_list_head;
+    for (; it != NULL; it = it->next)
+    {
+        if (it->native_window == window)
+        {
+            return true;
+        }
+    }
+    return false;
+}
+
+static inline void _associateWindowWithSurfaceList(EGLNativeWindowType window, EGLSurface surface)
+{
+    window_list_item * new_list_item = malloc(sizeof(window_list_item));
+    memset(new_list_item, 0, sizeof(window_list_item));
+
+    new_list_item->native_window = window;
+    new_list_item->attached_surface = surface;
+
+    if (window_surface_association_list_tail)
+    {
+        window_surface_association_list_tail->next = new_list_item;
+        new_list_item->prev = window_surface_association_list_tail;
+
+        window_surface_association_list_tail = new_list_item;
+    }
+    else
+    {
+        window_surface_association_list_head = new_list_item;
+        window_surface_association_list_tail = new_list_item;
+    }
+}
+
+static inline void _disassociateWindowWithSurfaceList(EGLSurface surface)
+{
+    if (window_surface_association_list_head != NULL)
+    {
+        if (window_surface_association_list_head == window_surface_association_list_tail &&
+                window_surface_association_list_head->attached_surface == surface)
+        {
+            free(window_surface_association_list_head);
+            window_surface_association_list_head = NULL;
+            window_surface_association_list_tail = NULL;
+        }
+        else
+        {
+            struct _window_list_item * it = window_surface_association_list_head;
+
+            for (;it != NULL; it = it->next)
+            {
+                if (it->attached_surface == surface)
+                {
+                    struct _window_list_item *next_element = it->next;
+                    struct _window_list_item *prev_element = it->prev;
+
+                    free (it);
+
+                    if (prev_element)
+                        prev_element->next = next_element;
+                    if (next_element)
+                        next_element->prev = prev_element;
+
+                    if (it == window_surface_association_list_tail)
+                        window_surface_association_list_tail = prev_element;
+
+                    if (it == window_surface_association_list_head)
+                        window_surface_association_list_head = next_element;
+                }
+            }
+        }
+    }
+}
 
 /**
  * Macros to help return an API entrypoint.
@@ -690,9 +780,20 @@ eglCreateWindowSurface(EGLDisplay dpy, EGLConfig config,
                        EGLNativeWindowType window, const EGLint *attrib_list)
 {
    _EGLDisplay *disp = _eglLockDisplay(dpy);
+   EGLSurface window_surface = NULL;
    STATIC_ASSERT(sizeof(void*) == sizeof(window));
-   return _eglCreateWindowSurfaceCommon(disp, config, (void*) window,
-                                        attrib_list);
+
+   //check if window have already created surface to it
+   if (_isWindowAssociatedWithSurface(window))
+       RETURN_EGL_ERROR(disp, EGL_BAD_ALLOC, EGL_NO_SURFACE);
+
+   window_surface = _eglCreateWindowSurfaceCommon(disp, config, (void*) window,
+                                                  attrib_list);
+   //add window with attached surface to list,
+   //it will be freed when eglDestroySurface will be called
+   if (window_surface != EGL_NO_SURFACE)
+       _associateWindowWithSurfaceList(window, window_surface);
+
+   return window_surface;
 }
 
 
@@ -805,6 +906,9 @@ eglDestroySurface(EGLDisplay dpy, EGLSurface surface)
    _eglUnlinkSurface(surf);
    ret = drv->API.DestroySurface(drv, disp, surf);
 
+   //remove surface association with window if exist
+   _disassociateWindowWithSurfaceList(surface);
+
    RETURN_EGL_EVAL(disp, ret);
 }
 
-- 
2.7.0.rc3

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