agl-shell: Add bound_ok and bound_fail events and a default destructor

As we're increasing the amount of combinations we could have in the AGL
platforms, in which we're mixing various platforms, we require a way
to tell clients that there's already a shell client which in charge.

We can't really have multiple shell clients managing the windows and
surfaces, but in the same time we don't want to sever the wayland
connection the way it happens currently. Racy alternatives might exist,
which  avoid advertising the interface altogether once a
client did bind to the interface but that's not really a
viable solution.

So instead of doing that, this patch introduces two new events which
tells the client that it was either successful, and it can continue
issue requests and receive events or a that it the bind failed. The
client can chose to wait and try later and abandon to bind to the
agl_shell intefface, and behave like a regular client.

While doing an update to protocol to add those two events this patch add
also a default destructor for the protocol.

Bug-AGL: SPEC-4502
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: Iacb86a668d1c4630724eecdb18e4b4c2d4e8e34a

4 files changed, 139 insertions, 12 deletions

diff --git a/protocol/agl-shell.xml b/protocol/agl-shell.xml
index 11a65a1..84a423c 100644
--- a/protocol/agl-shell.xml
+++ b/protocol/agl-shell.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <protocol name="agl_shell">
   <copyright>
-    Copyright © 2019 Collabora, Ltd.
+    Copyright © 2019, 2022 Collabora, Ltd.
 
     Permission is hereby granted, free of charge, to any person obtaining a
     copy of this software and associated documentation files (the "Software"),
@@ -22,10 +22,36 @@
     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     DEALINGS IN THE SOFTWARE.
   </copyright>
-  <interface name="agl_shell" version="1">
-    <description summary="user interface for weston-ivi">
+  <interface name="agl_shell" version="2">
+    <description summary="user interface for Automotive Grade Linux platform">
+      Starting with version 2 of the protocol, the client is required to wait
+      for the 'bound_ok' or 'bound_fail' events in order to proceed further.
+
+      In case the client gets a 'bound_fail' event then it should consider that
+      there's another client already bound to the agl_shell protocol.
+      A client that receives a 'bound_ok' event should consider that there's
+      no other client already bound to the interface and can proceed further.
+
+      If the client uses an older version of the protocol it will receive
+      automatically an error and the compositor will terminate the connection,
+      if there's another client already bound the interface.
+
+      If the client receives the 'bound_fail' event and attempts to use the
+      interface further it will receive an error and the compositor will
+      terminate the connection. After the 'bound_fail' event was received the
+      client should call the destructor, which has been added with version 2
+      of the protocol. The client is free to try at a later point in time to
+      see if it will receive the 'bound_ok' event, but there's no explicit way
+      of finding out when that event will be delivered.
+      It is assumed that it can infer that information through other
+      means/other channels.
     </description>
 
+    <request name="destroy" type="destructor" since="2">
+      <description summary="destroys the factory object">
+      </description>
+    </request>
+
     <enum name="error">
       <entry name="invalid_argument" value="0"/>
       <entry name="background_exists" value="1"/>
@@ -113,5 +139,22 @@
       <arg name="app_id" type="string"/>
       <arg name="output" type="object" interface="wl_output"/>
     </request>
+
+    <event name="bound_ok" since="2">
+     <description summary="event sent if binding was ok">
+        Informs the client that it was able to bind the agl_shell
+        interface succesfully. Clients are required to wait for this
+        event before continuing further.
+     </description>
+    </event>
+
+    <event name="bound_fail" since="2">
+      <description summary="event sent if binding was nok">
+        Informs the client that binding to the agl_shell interface was
+        unsuccesfull. Clients are required to wait for this event for
+        continuing further.
+      </description>
+    </event>
+
   </interface>
 </protocol>
diff --git a/src/desktop.c b/src/desktop.c
index b2907fe..1351508 100644
--- a/src/desktop.c
+++ b/src/desktop.c
@@ -164,6 +164,14 @@ desktop_surface_added(struct weston_desktop_surface *dsurface, void *userdata)
 	dclient = weston_desktop_surface_get_client(dsurface);
 	client = weston_desktop_client_get_client(dclient);
 
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED) {
+		wl_client_post_implementation_error(client,
+				       "agl_shell has already been bound. "
+				       "Check out bound_fail event");
+		return;
+	}
+
 	surface = zalloc(sizeof *surface);
 	if (!surface) {
 		wl_client_post_no_memory(client);
@@ -250,10 +258,20 @@ desktop_surface_removed(struct weston_desktop_surface *dsurface, void *userdata)
 	struct weston_surface *wsurface =
 		weston_desktop_surface_get_surface(dsurface);
 	const char *app_id = NULL;
-	struct weston_seat *wseat = get_ivi_shell_weston_first_seat(surface->ivi);
-	struct ivi_shell_seat *ivi_seat = get_ivi_shell_seat(wseat);
+	struct weston_seat *wseat = NULL;
+	struct ivi_shell_seat *ivi_seat = NULL;
+	struct ivi_output *output = NULL;
+
+	/* we might not have a valid ivi_surface if _added failed due to
+	 * protocol errors */
+	if (!surface)
+		return;
+
+	wseat = get_ivi_shell_weston_first_seat(surface->ivi);
+	if (wseat)
+		ivi_seat = get_ivi_shell_seat(wseat);
 
-	struct ivi_output *output = ivi_layout_get_output_from_surface(surface);
+	output = ivi_layout_get_output_from_surface(surface);
 
 	wl_list_remove(&surface->listener_advertise_app.link);
 	surface->listener_advertise_app.notify = NULL;
diff --git a/src/ivi-compositor.h b/src/ivi-compositor.h
index 78d1acd..dff11b9 100644
--- a/src/ivi-compositor.h
+++ b/src/ivi-compositor.h
@@ -46,6 +46,11 @@ struct desktop_client {
 	struct wl_list link;	/* ivi_compositor::desktop_clients */
 };
 
+enum agl_shell_bound_status {
+	BOUND_OK,
+	BOUND_FAILED,
+};
+
 struct ivi_compositor {
 	struct weston_compositor *compositor;
 	struct weston_config *config;
@@ -81,6 +86,7 @@ struct ivi_compositor {
 		struct wl_client *client;
 		struct wl_resource *resource;
 		bool ready;
+		enum agl_shell_bound_status status;
 	} shell_client;
 
 	struct wl_list desktop_clients;	/* desktop_client::link */
diff --git a/src/shell.c b/src/shell.c
index dc07c26..913174f 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -1017,10 +1017,20 @@ shell_ready(struct wl_client *client, struct wl_resource *shell_res)
 	struct ivi_output *output;
 	struct ivi_surface *surface, *tmp;
 
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED) {
+		wl_resource_post_error(shell_res,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "agl_shell has already been bound. "
+				       "Check out bound_fail event");
+		return;
+	}
+
 	/* Init already finished. Do nothing */
 	if (ivi->shell_client.ready)
 		return;
 
+
 	ivi->shell_client.ready = true;
 
 	wl_list_for_each(output, &ivi->outputs, link) {
@@ -1047,9 +1057,19 @@ shell_set_background(struct wl_client *client,
 	struct weston_output *woutput = weston_head_get_output(head);
 	struct ivi_output *output = to_ivi_output(woutput);
 	struct weston_surface *wsurface = wl_resource_get_user_data(surface_res);
+	struct ivi_compositor *ivi = wl_resource_get_user_data(shell_res);
 	struct weston_desktop_surface *dsurface;
 	struct ivi_surface *surface;
 
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED) {
+		wl_resource_post_error(shell_res,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "agl_shell has already been bound. "
+				       "Check out bound_fail event");
+		return;
+	}
+
 	dsurface = weston_surface_get_desktop_surface(wsurface);
 	if (!dsurface) {
 		wl_resource_post_error(shell_res,
@@ -1098,11 +1118,21 @@ shell_set_panel(struct wl_client *client,
 	struct weston_output *woutput = weston_head_get_output(head);
 	struct ivi_output *output = to_ivi_output(woutput);
 	struct weston_surface *wsurface = wl_resource_get_user_data(surface_res);
+	struct ivi_compositor *ivi = wl_resource_get_user_data(shell_res);
 	struct weston_desktop_surface *dsurface;
 	struct ivi_surface *surface;
 	struct ivi_surface **member;
 	int32_t width = 0, height = 0;
 
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED) {
+		wl_resource_post_error(shell_res,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "agl_shell has already been bound. "
+				       "Check out bound_fail event");
+		return;
+	}
+
 	dsurface = weston_surface_get_desktop_surface(wsurface);
 	if (!dsurface) {
 		wl_resource_post_error(shell_res,
@@ -1208,8 +1238,18 @@ shell_activate_app(struct wl_client *client,
 {
 	struct weston_head *head = weston_head_from_resource(output_res);
 	struct weston_output *woutput = weston_head_get_output(head);
+	struct ivi_compositor *ivi = wl_resource_get_user_data(shell_res);
 	struct ivi_output *output = to_ivi_output(woutput);
 
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED) {
+		wl_resource_post_error(shell_res,
+				       WL_DISPLAY_ERROR_INVALID_OBJECT,
+				       "agl_shell has already been bound. "
+				       "Check out bound_fail event");
+		return;
+	}
+
 	ivi_layout_activate(output, app_id);
 }
 
@@ -1241,7 +1281,14 @@ shell_deactivate_app(struct wl_client *client,
 				  NULL, AGL_SHELL_DESKTOP_APP_STATE_DEACTIVATED);
 }
 
+/* stub, no usage for the time being */
+static void
+shell_destroy(struct wl_client *client, struct wl_resource *res)
+{
+}
+
 static const struct agl_shell_interface agl_shell_implementation = {
+	.destroy = shell_destroy,
 	.ready = shell_ready,
 	.set_background = shell_set_background,
 	.set_panel = shell_set_panel,
@@ -1334,6 +1381,11 @@ unbind_agl_shell(struct wl_resource *resource)
 	struct ivi_surface *surf, *surf_tmp;
 
 	ivi = wl_resource_get_user_data(resource);
+
+	if (ivi->shell_client.resource &&
+	    ivi->shell_client.status == BOUND_FAILED)
+		return;
+
 	wl_list_for_each(output, &ivi->outputs, link) {
 		/* reset the active surf if there's one present */
 		if (output->active) {
@@ -1383,22 +1435,30 @@ bind_agl_shell(struct wl_client *client,
 		return;
 	}
 
-	resource = wl_resource_create(client, &agl_shell_interface,
-				      1, id);
+	resource = wl_resource_create(client, &agl_shell_interface, version, id);
 	if (!resource) {
 		wl_client_post_no_memory(client);
 		return;
 	}
 
 	if (ivi->shell_client.resource) {
-		wl_resource_post_error(resource, WL_DISPLAY_ERROR_INVALID_OBJECT,
-				       "agl_shell has already been bound");
-		return;
+		if (wl_resource_get_version(resource) == 1) {
+			wl_resource_post_error(resource, WL_DISPLAY_ERROR_INVALID_OBJECT,
+					       "agl_shell has already been bound");
+			return;
+		}
+
+		agl_shell_send_bound_fail(resource);
+		ivi->shell_client.status = BOUND_FAILED;
 	}
 
 	wl_resource_set_implementation(resource, &agl_shell_implementation,
 				       ivi, unbind_agl_shell);
 	ivi->shell_client.resource = resource;
+
+	if (ivi->shell_client.status == BOUND_OK &&
+	    wl_resource_get_version(resource) >= AGL_SHELL_BOUND_OK_SINCE_VERSION)
+		agl_shell_send_bound_ok(ivi->shell_client.resource);
 }
 
 static void
@@ -1457,7 +1517,7 @@ int
 ivi_shell_create_global(struct ivi_compositor *ivi)
 {
 	ivi->agl_shell = wl_global_create(ivi->compositor->wl_display,
-					  &agl_shell_interface, 1,
+					  &agl_shell_interface, 2,
 					  ivi, bind_agl_shell);
 	if (!ivi->agl_shell) {
 		weston_log("Failed to create wayland global.\n");