swapchain: Add wlr_swapchain_has_buffer

include/wlr/render/swapchain.h

@@ -38,6 +38,12 @@ void wlr_swapchain_destroy(struct wlr_swapchain *swapchain);
  */
 struct wlr_buffer *wlr_swapchain_acquire(struct wlr_swapchain *swapchain,
 	int *age);
+/**
+ * Returns true if this buffer has been created by this swapchain, and false
+ * otherwise.
+ */
+bool wlr_swapchain_has_buffer(struct wlr_swapchain *swapchain,
+	struct wlr_buffer *buffer);
 /**
  * Mark the buffer as submitted for presentation. This needs to be called by
  * swap chain users on frame boundaries.

render/swapchain.c

@@ -113,7 +113,7 @@ struct wlr_buffer *wlr_swapchain_acquire(struct wlr_swapchain *swapchain,
 	return slot_acquire(swapchain, free_slot, age);
 }
 
-static bool swapchain_has_buffer(struct wlr_swapchain *swapchain,
+bool wlr_swapchain_has_buffer(struct wlr_swapchain *swapchain,
 		struct wlr_buffer *buffer) {
 	for (size_t i = 0; i < WLR_SWAPCHAIN_CAP; i++) {
 		struct wlr_swapchain_slot *slot = &swapchain->slots[i];
@@ -128,7 +128,7 @@ void wlr_swapchain_set_buffer_submitted(struct wlr_swapchain *swapchain,
 		struct wlr_buffer *buffer) {
 	assert(buffer != NULL);
 
-	if (!swapchain_has_buffer(swapchain, buffer)) {
+	if (!wlr_swapchain_has_buffer(swapchain, buffer)) {
 		return;
 	}