libweston: consolidate weston_compositor_create_output(_with_head)

Add a struct weston_head parameter to weston_compositor_create_output()
and fold weston_compositor_create_output_with_head() into it.

See: https://gitlab.freedesktop.org/wayland/weston/-/issues/268

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

compositor/main.c

@@ -1696,8 +1696,8 @@ simple_head_enable(struct wet_compositor *wet, struct weston_head *head)
 	struct weston_output *output;
 	int ret = 0;
 
-	output = weston_compositor_create_output_with_head(wet->compositor,
-							   head);
+	output = weston_compositor_create_output(wet->compositor, head,
+						 head->name);
 	if (!output) {
 		weston_log("Could not create an output for head \"%s\".\n",
 			   weston_head_get_name(head));
@@ -2162,7 +2162,7 @@ wet_layoutput_create_output(struct wet_layoutput *lo, const char *name)
 
 	output->output =
 		weston_compositor_create_output(lo->compositor->compositor,
-						name);
+						NULL, name);
 	if (!output->output) {
 		free(output);
 		return NULL;

doc/sphinx/toc/libweston/images/create_output.msc

@@ -11,7 +11,7 @@ msc {
 	--- [label = "Compositor creates an output for a head"];
 
 	c box c [label = "Have an existing head to process."];
-	c => w [label = "weston_compositor_create_output_with_head()"];
+	c => w [label = "weston_compositor_create_output()"];
 	w => b [label = "weston_backend::create_output()"];
 	w << b [label = "an empty output, no hw resources"];
 	w => b [label = "weston_output::attach_head()"];

include/libweston/libweston.h

@@ -2228,11 +2228,7 @@ weston_compositor_find_output_by_name(struct weston_compositor *compositor,
 
 struct weston_output *
 weston_compositor_create_output(struct weston_compositor *compositor,
-				const char *name);
-
-struct weston_output *
-weston_compositor_create_output_with_head(struct weston_compositor *compositor,
-					  struct weston_head *head);
+				struct weston_head *head, const char *name);
 
 void
 weston_output_destroy(struct weston_output *output);

libweston/compositor.c

@@ -7306,13 +7306,15 @@ weston_compositor_find_output_by_name(struct weston_compositor *compositor,
 	return NULL;
 }
 
-/** Create a named output
+/** Create a named output for an unused head
  *
  * \param compositor The compositor.
+ * \param head The head to attach to the output.
  * \param name The name for the output.
  * \return A new \c weston_output, or NULL on failure.
  *
- * This creates a new weston_output that starts with no heads attached.
+ * This creates a new weston_output that starts with the given head attached.
+ * The head must not be already attached to another output.
  *
  * An output must be configured and it must have at least one head before
  * it can be enabled.
@@ -7321,8 +7323,11 @@ weston_compositor_find_output_by_name(struct weston_compositor *compositor,
  */
 WL_EXPORT struct weston_output *
 weston_compositor_create_output(struct weston_compositor *compositor,
+				struct weston_head *head,
 				const char *name)
 {
+	struct weston_output *output;
+
 	assert(compositor->backend->create_output);
 
 	if (weston_compositor_find_output_by_name(compositor, name)) {
@@ -7331,34 +7336,11 @@ weston_compositor_create_output(struct weston_compositor *compositor,
 		return NULL;
 	}
 
-	return compositor->backend->create_output(compositor, name);
-}
-
-/** Create an output for an unused head
- *
- * \param compositor The compositor.
- * \param head The head to attach to the output.
- * \return A new \c weston_output, or NULL on failure.
- *
- * This creates a new weston_output that starts with the given head attached.
- * The output inherits the name of the head. The head must not be already
- * attached to another output.
- *
- * An output must be configured before it can be enabled.
- *
- * \ingroup compositor
- */
-WL_EXPORT struct weston_output *
-weston_compositor_create_output_with_head(struct weston_compositor *compositor,
-					  struct weston_head *head)
-{
-	struct weston_output *output;
-
-	output = weston_compositor_create_output(compositor, head->name);
+	output = compositor->backend->create_output(compositor, name);
 	if (!output)
 		return NULL;
 
-	if (weston_output_attach_head(output, head) < 0) {
+	if (head && weston_output_attach_head(output, head) < 0) {
 		weston_output_destroy(output);
 		return NULL;
 	}