Wayland: Use tags to verify proxy ownership

This is in preparation for adding support for libdecor, which creates
its own proxies on our display.  It will likely also be helpful to some
people using native access on Wayland.

This is partly based on the implementation of libdecor support in
PR #1693 by @ christianrauch.

src/wl_init.c

@@ -507,6 +507,8 @@ int _glfwInitWayland(void)
     _glfw.wl.keyRepeatTimerfd = -1;
     _glfw.wl.cursorTimerfd = -1;
 
+    _glfw.wl.tag = glfwGetVersionString();
+
     _glfw.wl.client.display_flush = (PFN_wl_display_flush)
         _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_display_flush");
     _glfw.wl.client.display_cancel_read = (PFN_wl_display_cancel_read)
@@ -537,6 +539,10 @@ int _glfwInitWayland(void)
         _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_proxy_get_user_data");
     _glfw.wl.client.proxy_set_user_data = (PFN_wl_proxy_set_user_data)
         _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_proxy_set_user_data");
+    _glfw.wl.client.proxy_get_tag = (PFN_wl_proxy_get_tag)
+        _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_proxy_get_tag");
+    _glfw.wl.client.proxy_set_tag = (PFN_wl_proxy_set_tag)
+        _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_proxy_set_tag");
     _glfw.wl.client.proxy_get_version = (PFN_wl_proxy_get_version)
         _glfwPlatformGetModuleSymbol(_glfw.wl.client.handle, "wl_proxy_get_version");
     _glfw.wl.client.proxy_marshal_flags = (PFN_wl_proxy_marshal_flags)
@@ -556,7 +562,9 @@ int _glfwInitWayland(void)
         !_glfw.wl.client.proxy_marshal_constructor ||
         !_glfw.wl.client.proxy_marshal_constructor_versioned ||
         !_glfw.wl.client.proxy_get_user_data ||
-        !_glfw.wl.client.proxy_set_user_data)
+        !_glfw.wl.client.proxy_set_user_data ||
+        !_glfw.wl.client.proxy_get_tag ||
+        !_glfw.wl.client.proxy_set_tag)
     {
         _glfwInputError(GLFW_PLATFORM_ERROR,
                         "Wayland: Failed to load libwayland-client entry point");

src/wl_monitor.c

@@ -191,6 +191,7 @@ void _glfwAddOutputWayland(uint32_t name, uint32_t version)
     monitor->wl.output = output;
     monitor->wl.name = name;
 
+    wl_proxy_set_tag((struct wl_proxy*) output, &_glfw.wl.tag);
     wl_output_add_listener(output, &outputListener, monitor);
 }
 

src/wl_platform.h

@@ -61,6 +61,8 @@ typedef struct wl_proxy* (* PFN_wl_proxy_marshal_constructor)(struct wl_proxy*,u
 typedef struct wl_proxy* (* PFN_wl_proxy_marshal_constructor_versioned)(struct wl_proxy*,uint32_t,const struct wl_interface*,uint32_t,...);
 typedef void* (* PFN_wl_proxy_get_user_data)(struct wl_proxy*);
 typedef void (* PFN_wl_proxy_set_user_data)(struct wl_proxy*,void*);
+typedef void (* PFN_wl_proxy_set_tag)(struct wl_proxy*,const char*const*);
+typedef const char* const* (* PFN_wl_proxy_get_tag)(struct wl_proxy*);
 typedef uint32_t (* PFN_wl_proxy_get_version)(struct wl_proxy*);
 typedef struct wl_proxy* (* PFN_wl_proxy_marshal_flags)(struct wl_proxy*,uint32_t,const struct wl_interface*,uint32_t,uint32_t,...);
 #define wl_display_flush _glfw.wl.client.display_flush
@@ -78,6 +80,8 @@ typedef struct wl_proxy* (* PFN_wl_proxy_marshal_flags)(struct wl_proxy*,uint32_
 #define wl_proxy_marshal_constructor_versioned _glfw.wl.client.proxy_marshal_constructor_versioned
 #define wl_proxy_get_user_data _glfw.wl.client.proxy_get_user_data
 #define wl_proxy_set_user_data _glfw.wl.client.proxy_set_user_data
+#define wl_proxy_get_tag _glfw.wl.client.proxy_get_tag
+#define wl_proxy_set_tag _glfw.wl.client.proxy_set_tag
 #define wl_proxy_get_version _glfw.wl.client.proxy_get_version
 #define wl_proxy_marshal_flags _glfw.wl.client.proxy_marshal_flags
 
@@ -311,6 +315,8 @@ typedef struct _GLFWlibraryWayland
     _GLFWwindow*                dragFocus;
     uint32_t                    dragSerial;
 
+    const char*                 tag;
+
     struct wl_cursor_theme*     cursorTheme;
     struct wl_cursor_theme*     cursorThemeHiDPI;
     struct wl_surface*          cursorSurface;
@@ -388,6 +394,8 @@ typedef struct _GLFWlibraryWayland
         PFN_wl_proxy_marshal_constructor_versioned  proxy_marshal_constructor_versioned;
         PFN_wl_proxy_get_user_data                  proxy_get_user_data;
         PFN_wl_proxy_set_user_data                  proxy_set_user_data;
+        PFN_wl_proxy_get_tag                        proxy_get_tag;
+        PFN_wl_proxy_set_tag                        proxy_set_tag;
         PFN_wl_proxy_get_version                    proxy_get_version;
         PFN_wl_proxy_marshal_flags                  proxy_marshal_flags;
     } client;

src/wl_window.c

@@ -199,6 +199,7 @@ static void createFallbackDecoration(_GLFWdecorationWayland* decoration,
                                      int width, int height)
 {
     decoration->surface = wl_compositor_create_surface(_glfw.wl.compositor);
+    wl_proxy_set_tag((struct wl_proxy*) decoration->surface, &_glfw.wl.tag);
     decoration->subsurface =
         wl_subcompositor_get_subsurface(_glfw.wl.subcompositor,
                                         decoration->surface, parent);
@@ -371,6 +372,9 @@ static void surfaceHandleEnter(void* userData,
                                struct wl_surface* surface,
                                struct wl_output* output)
 {
+    if (wl_proxy_get_tag((struct wl_proxy*) output) != &_glfw.wl.tag)
+        return;
+
     _GLFWwindow* window = userData;
     _GLFWmonitor* monitor = wl_output_get_user_data(output);
 
@@ -391,6 +395,9 @@ static void surfaceHandleLeave(void* userData,
                                struct wl_surface* surface,
                                struct wl_output* output)
 {
+    if (wl_proxy_get_tag((struct wl_proxy*) output) != &_glfw.wl.tag)
+        return;
+
     _GLFWwindow* window = userData;
     _GLFWmonitor* monitor = wl_output_get_user_data(output);
     GLFWbool found = GLFW_FALSE;
@@ -729,6 +736,7 @@ static GLFWbool createNativeSurface(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
+    wl_proxy_set_tag((struct wl_proxy*) window->wl.surface, &_glfw.wl.tag);
     wl_surface_add_listener(window->wl.surface,
                             &surfaceListener,
                             window);
@@ -1063,6 +1071,9 @@ static void pointerHandleEnter(void* userData,
     if (!surface)
         return;
 
+    if (wl_proxy_get_tag((struct wl_proxy*) surface) != &_glfw.wl.tag)
+        return;
+
     _GLFWdecorationSideWayland focus = mainWindow;
     _GLFWwindow* window = wl_surface_get_user_data(surface);
     if (!window)
@@ -1088,8 +1099,13 @@ static void pointerHandleLeave(void* userData,
                                uint32_t serial,
                                struct wl_surface* surface)
 {
-    _GLFWwindow* window = _glfw.wl.pointerFocus;
+    if (!surface)
+        return;
 
+    if (wl_proxy_get_tag((struct wl_proxy*) surface) != &_glfw.wl.tag)
+        return;
+
+    _GLFWwindow* window = _glfw.wl.pointerFocus;
     if (!window)
         return;
 
@@ -1681,7 +1697,10 @@ static void dataDeviceHandleEnter(void* userData,
             _GLFWwindow* window = NULL;
 
             if (surface)
+            {
+                if (wl_proxy_get_tag((struct wl_proxy*) surface) == &_glfw.wl.tag)
                     window = wl_surface_get_user_data(surface);
+            }
 
             if (window && _glfw.wl.offers[i].text_uri_list)
             {
@@ -1696,6 +1715,9 @@ static void dataDeviceHandleEnter(void* userData,
         }
     }
 
+    if (wl_proxy_get_tag((struct wl_proxy*) surface) != &_glfw.wl.tag)
+        return;
+
     if (_glfw.wl.dragOffer)
         wl_data_offer_accept(offer, serial, "text/uri-list");
     else