[DEBUG] Add dbg-txn protocol

include/wlr/types/wlr_dbg_txn.h

@@ -0,0 +1,23 @@
+/*
+ * This an unstable interface of wlroots. No guarantees are made regarding the
+ * future consistency of this API.
+ */
+#ifndef WLR_USE_UNSTABLE
+#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
+#endif
+
+#ifndef WLR_TYPES_WLR_DBG_TXN_H
+#define WLR_TYPES_WLR_DBG_TXN_H
+
+#include <wayland-server-core.h>
+#include "dbg-txn-protocol.h"
+
+struct wlr_dbg_txn_manager {
+	struct wl_global *global;
+
+	struct wl_listener display_destroy;
+};
+
+struct wlr_dbg_txn_manager *wlr_dbg_txn_manager_create(struct wl_display *display);
+
+#endif

protocol/dbg-txn.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<protocol name="dbg_txn">
+  <interface name="dbg_txn_manager" version="1">
+    <request name="get_txn">
+      <arg name="id" type="new_id" interface="dbg_txn"/>
+    </request>
+  </interface>
+
+  <interface name="dbg_txn" version="1">
+    <request name="add_surface">
+      <arg name="surface" type="object" interface="wl_surface"/>
+    </request>
+
+    <request name="commit" type="destructor">
+    </request>
+  </interface>
+</protocol>

protocol/meson.build

@@ -64,6 +64,8 @@ protocols = {
 	'wlr-output-power-management-unstable-v1': 'wlr-output-power-management-unstable-v1.xml',
 	'wlr-screencopy-unstable-v1': 'wlr-screencopy-unstable-v1.xml',
 	'wlr-virtual-pointer-unstable-v1': 'wlr-virtual-pointer-unstable-v1.xml',
+
+	'dbg-txn': 'dbg-txn.xml',
 }
 
 protocols_code = {}

tinywl/meson.build

@@ -1,5 +1,6 @@
 executable(
 	'tinywl',
-	['tinywl.c', protocols_server_header['xdg-shell']],
+	['tinywl.c', protocols_server_header['xdg-shell'],
+		protocols_server_header['dbg-txn'], protocols_server_header['viewporter']],
 	dependencies: wlroots,
 )

tinywl/tinywl.c

@@ -12,6 +12,7 @@
 #include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_compositor.h>
 #include <wlr/types/wlr_data_device.h>
+#include <wlr/types/wlr_dbg_txn.h>
 #include <wlr/types/wlr_input_device.h>
 #include <wlr/types/wlr_keyboard.h>
 #include <wlr/types/wlr_output.h>
@@ -20,6 +21,7 @@
 #include <wlr/types/wlr_scene.h>
 #include <wlr/types/wlr_seat.h>
 #include <wlr/types/wlr_subcompositor.h>
+#include <wlr/types/wlr_viewporter.h>
 #include <wlr/types/wlr_xcursor_manager.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
@@ -981,6 +983,9 @@ int main(int argc, char *argv[]) {
 	 * HiDPI support). */
 	server.cursor_mgr = wlr_xcursor_manager_create(NULL, 24);
 
+	wlr_viewporter_create(server.wl_display);
+	wlr_dbg_txn_manager_create(server.wl_display);
+
 	/*
 	 * wlr_cursor *only* displays an image on screen. It does not move around
 	 * when the pointer moves. However, we can attach input devices to it, and

types/meson.build

@@ -40,6 +40,7 @@ wlr_files += files(
 	'wlr_cursor.c',
 	'wlr_damage_ring.c',
 	'wlr_data_control_v1.c',
+	'wlr_dbg_txn.c',
 	'wlr_drm.c',
 	'wlr_export_dmabuf_v1.c',
 	'wlr_foreign_toplevel_management_v1.c',

types/wlr_dbg_txn.c

@@ -0,0 +1,157 @@
+#include <assert.h>
+#include <stdlib.h>
+
+#include <wlr/types/wlr_compositor.h>
+#include <wlr/types/wlr_dbg_txn.h>
+
+struct wlr_dbg_txn {
+	struct wl_resource *resource;
+	struct wl_list locks;
+};
+
+struct wlr_dbg_txn_lock {
+	struct wlr_addon addon;
+	struct wlr_surface_state_lock lock;
+	struct wl_list link;
+};
+
+static const struct dbg_txn_interface txn_impl;
+
+static struct wlr_dbg_txn *txn_from_resource(struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource, &dbg_txn_interface, &txn_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+static void txn_lock_destroy(struct wlr_dbg_txn_lock *lock) {
+	wlr_surface_state_lock_release(&lock->lock);
+	wl_list_remove(&lock->link);
+	wlr_addon_finish(&lock->addon);
+	free(lock);
+}
+
+static void addon_handle_destroy(struct wlr_addon *addon) {
+	struct wlr_dbg_txn_lock *lock = wl_container_of(addon, lock, addon);
+	txn_lock_destroy(lock);
+}
+
+static struct wlr_addon_interface addon_impl = {
+	.name = "wlr_dbg_txn_lock",
+	.destroy = addon_handle_destroy,
+};
+
+static void txn_handle_add_surface(struct wl_client *client, struct wl_resource *resource,
+		struct wl_resource *surface_resource) {
+	struct wlr_surface *surface = wlr_surface_from_resource(surface_resource);
+	if (wlr_addon_find(&surface->addons, NULL, &addon_impl) != NULL) {
+		wl_resource_post_error(resource, -1, "already added");
+		return;
+	}
+
+	struct wlr_dbg_txn *txn = txn_from_resource(resource);
+	struct wlr_dbg_txn_lock *lock = calloc(1, sizeof(*lock));
+	assert(lock != NULL);
+	wlr_surface_state_lock_acquire(&lock->lock, surface);
+	wl_list_insert(&txn->locks, &lock->link);
+	wlr_addon_init(&lock->addon, &surface->addons, NULL, &addon_impl);
+}
+
+static void txn_handle_commit(struct wl_client *client, struct wl_resource *resource) {
+	struct wlr_dbg_txn *txn = txn_from_resource(resource);
+
+	struct wl_array buffer;
+	wl_array_init(&buffer);
+
+	struct wlr_surface_transaction surface_txn;
+	wlr_surface_transaction_init(&surface_txn, &buffer);
+
+	bool ok = true;
+	struct wlr_dbg_txn_lock *lock;
+	wl_list_for_each(lock, &txn->locks, link) {
+		if (!wlr_surface_transaction_add_lock(&surface_txn, &lock->lock)) {
+			wlr_surface_transaction_drop(&surface_txn);
+			ok = false;
+			break;
+		}
+	}
+	if (ok) {
+		ok = wlr_surface_transaction_commit(&surface_txn);
+	}
+	if (!ok) {
+		wl_resource_post_no_memory(resource);
+	}
+
+	wl_array_release(&buffer);
+	wl_resource_destroy(resource);
+}
+
+static const struct dbg_txn_interface txn_impl = {
+	.add_surface = txn_handle_add_surface,
+	.commit = txn_handle_commit,
+};
+
+static void txn_handle_resource_destroy(struct wl_resource *resource) {
+	struct wlr_dbg_txn *txn = txn_from_resource(resource);
+	struct wlr_dbg_txn_lock *lock, *tmp;
+	wl_list_for_each_safe(lock, tmp, &txn->locks, link) {
+		txn_lock_destroy(lock);
+	}
+	free(txn);
+}
+
+static void manager_handle_get_txn(struct wl_client *client,
+		struct wl_resource *resource, uint32_t id) {
+	struct wlr_dbg_txn *txn = calloc(1, sizeof(*txn));
+	if (txn == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
+	txn->resource = wl_resource_create(client, &dbg_txn_interface, 1, id);
+	assert(txn->resource != NULL);
+
+	wl_resource_set_implementation(txn->resource, &txn_impl, txn, txn_handle_resource_destroy);
+
+	wl_list_init(&txn->locks);
+}
+
+static const struct dbg_txn_manager_interface manager_impl = {
+	.get_txn = manager_handle_get_txn,
+};
+
+static void manager_bind(struct wl_client *wl_client, void *data, uint32_t version, uint32_t id) {
+	struct wlr_dbg_txn_manager *manager = data;
+
+	struct wl_resource *resource =
+		wl_resource_create(wl_client, &wl_compositor_interface, version, id);
+	if (resource == NULL) {
+		wl_client_post_no_memory(wl_client);
+		return;
+	}
+	wl_resource_set_implementation(resource, &manager_impl, manager, NULL);
+}
+
+static void manager_handle_display_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_dbg_txn_manager *manager = wl_container_of(listener, manager, display_destroy);
+	wl_list_remove(&manager->display_destroy.link);
+	wl_global_destroy(manager->global);
+	free(manager);
+}
+
+struct wlr_dbg_txn_manager *wlr_dbg_txn_manager_create(struct wl_display *display) {
+	struct wlr_dbg_txn_manager *manager = calloc(1, sizeof(*manager));
+	if (!manager) {
+		return NULL;
+	}
+
+	manager->global = wl_global_create(display, &dbg_txn_manager_interface,
+		1, manager, manager_bind);
+	if (!manager->global) {
+		free(manager);
+		return NULL;
+	}
+
+	manager->display_destroy.notify = manager_handle_display_destroy;
+	wl_display_add_destroy_listener(display, &manager->display_destroy);
+
+	return manager;
+}