[PATCH weston v2] clients: Require EGL_MIN_SWAP_INTERVAL to be 0 for subsurfaces

[Jonas Ådahl]

Warn and fail when assert to create sub surfaces when swap interval 0 is
not supported by the EGL platform.

Programs wanting to add subsurfaces need to check whether it is
subsurfaces are supported by the display with the new
display_is_subsurfaces_supported() function.

Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
---

Changed since v1:

Coding style fix.

Require clients to check whether subsurfaces is supported or not prior to
adding them.


 clients/nested.c      |  6 ++++++
 clients/subsurfaces.c |  6 ++++++
 clients/window.c      | 30 ++++++++++++++++++++++++++++++
 clients/window.h      |  4 ++++
 4 files changed, 46 insertions(+)

diff --git a/clients/nested.c b/clients/nested.c
index f094237..f52173e 100644
--- a/clients/nested.c
+++ b/clients/nested.c
@@ -1127,6 +1127,12 @@ main(int argc, char *argv[])
 		return -1;
 	}
 
+	if (!display_is_subsurfaces_supported(display)) {
+		fprintf(stderr, "subsurface support required\n");
+		display_destroy(display);
+		return -1;
+	}
+
 	nested = nested_create(display);
 
 	launch_client(nested, "weston-nested-client");
diff --git a/clients/subsurfaces.c b/clients/subsurfaces.c
index fcbe496..8376399 100644
--- a/clients/subsurfaces.c
+++ b/clients/subsurfaces.c
@@ -792,6 +792,12 @@ main(int argc, char *argv[])
 		return -1;
 	}
 
+	if (!display_is_subsurfaces_supported(display)) {
+		fprintf(stderr, "subsurface support required\n");
+		display_destroy(display);
+		return -1;
+	}
+
 	app = demoapp_create(display);
 
 	display_run(display);
diff --git a/clients/window.c b/clients/window.c
index b45b499..3b95896 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -2023,6 +2023,9 @@ window_create_tooltip(struct tooltip *tooltip)
 
 	tooltip->widget = window_add_subsurface(parent->window, tooltip, SUBSURFACE_DESYNCHRONIZED);
 
+	if (!tooltip->widget)
+		return -1;
+
 	extents = get_text_extents(display, tooltip);
 	widget_set_redraw_handler(tooltip->widget, tooltip_redraw_handler);
 	widget_set_allocation(tooltip->widget,
@@ -4845,6 +4848,8 @@ window_add_subsurface(struct window *window, void *data,
 	struct wl_surface *parent;
 	struct wl_subcompositor *subcompo = window->display->subcompositor;
 
+	assert(display_is_subsurfaces_supported(window->display));
+
 	surface = surface_create(window);
 	surface->buffer_type = window_get_buffer_type(window);
 	widget = widget_create(window, surface, data);
@@ -5620,6 +5625,31 @@ display_has_subcompositor(struct display *display)
 	return display->subcompositor != NULL;
 }
 
+bool
+display_is_subsurfaces_supported(struct display *display)
+{
+	GLint min_swap_interval;
+
+	if (!display_has_subcompositor(display)) {
+		return false;
+	}
+
+	if (!eglGetConfigAttrib(display->dpy,
+				display->argb_config,
+				EGL_MIN_SWAP_INTERVAL,
+				&min_swap_interval)) {
+		fprintf(stderr, "failed to retrieve EGL_MIN_SWAP_INTERVAL\n");
+		return false;
+	}
+
+	if (min_swap_interval > 0) {
+		fprintf(stderr, "warning: EGLSwapInterval(0) not supported\n");
+		return false;
+	}
+
+	return true;
+}
+
 cairo_device_t *
 display_get_cairo_device(struct display *display)
 {
diff --git a/clients/window.h b/clients/window.h
index 5247f19..b47e0b2 100644
--- a/clients/window.h
+++ b/clients/window.h
@@ -28,6 +28,7 @@
 #include <xkbcommon/xkbcommon.h>
 #include <wayland-client.h>
 #include <cairo.h>
+#include <stdbool.h>
 #include "../shared/config-parser.h"
 #include "../shared/zalloc.h"
 
@@ -84,6 +85,9 @@ display_get_display(struct display *display);
 int
 display_has_subcompositor(struct display *display);
 
+bool
+display_is_subsurfaces_supported(struct display *display);
+
 cairo_device_t *
 display_get_cairo_device(struct display *display);
 
-- 
2.1.0