On Fri, Jul 9, 2021 at 1:34 PM Luiz Augusto von Dentz
[off-list ref] wrote:

Hi Howard,

On Wed, Jul 7, 2021 at 11:23 PM Howard Chung [off-list ref] wrote:

quoted

From: Yun-Hao Chung <redacted>

This implements functions to register/unregister state changed callback
functions, the functions will be called when a device's state changed.
Currently the state only shows initializing, available and removing,
which is enough for plugins to register dbus objects upon device
creation and unregister it upon device removal.

Reviewed-by: Miao-chen Chou <redacted>
---

 src/device.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/device.h | 13 +++++++++++
 2 files changed, 77 insertions(+)

diff --git a/src/device.c b/src/device.c
index e1d82eab0988..0d7444706336 100644
--- a/src/device.c
+++ b/src/device.c

@@ -81,6 +81,13 @@

 static DBusConnection *dbus_conn = NULL;
 static unsigned service_state_cb_id;
+static GSList *device_state_callbacks;

Use a struct queue instead of GSList.

Will do.

quoted

+
+struct device_state_callback {
+       btd_device_state_cb     cb;
+       void                    *user_data;
+       unsigned int            id;
+};

 struct btd_disconnect_data {
        guint id;

@@ -272,6 +279,8 @@ struct btd_device {

        GIOChannel      *att_io;
        guint           store_id;
+
+       enum btd_device_state_t state;
 };

 static const uint16_t uuid_list[] = {

@@ -4095,6 +4104,23 @@ static void gatt_service_removed(struct gatt_db_attribute *attr,
        gatt_services_changed(device);
 }

+static void device_change_state(struct btd_device *device,
+                                       enum btd_device_state_t new_state)
+{
+       GSList *l;
+       struct device_state_callback *cb_data;
+
+       if (device->state == new_state)
+               return;
+
+       for (l = device_state_callbacks; l != NULL; l = g_slist_next(l)) {
+               cb_data = l->data;
+               cb_data->cb(device, new_state, cb_data->user_data);
+       }
+
+       device->state = new_state;
+}
+
 static struct btd_device *device_new(struct btd_adapter *adapter,
                                const char *address)
 {

@@ -4158,6 +4184,8 @@ static struct btd_device *device_new(struct btd_adapter *adapter,

        device->refresh_discovery = btd_opts.refresh_discovery;

+       device_change_state(device, BTD_DEVICE_STATE_AVAILABLE);
+
        return btd_device_ref(device);
 }

@@ -6839,6 +6867,7 @@ void btd_device_unref(struct btd_device *device)

        DBG("Freeing device %s", device->path);

+       device_change_state(device, BTD_DEVICE_STATE_REMOVING);
        g_dbus_unregister_interface(dbus_conn, device->path, DEVICE_INTERFACE);
 }

@@ -6980,3 +7009,38 @@ void btd_device_cleanup(void)
 {
        btd_service_remove_state_cb(service_state_cb_id);
 }
+
+unsigned int btd_device_add_state_cb(btd_device_state_cb cb, void *user_data)
+{
+       struct device_state_callback *cb_data;
+       static unsigned int id;
+
+       cb_data = g_new0(struct device_state_callback, 1);
+       cb_data->cb = cb;
+       cb_data->user_data = user_data;
+       cb_data->id = ++id;
+
+       device_state_callbacks = g_slist_append(device_state_callbacks,
+                                                               cb_data);
+
+       return cb_data->id;
+}
+
+bool btd_device_remove_state_cb(unsigned int id)
+{
+       GSList *l;
+
+       for (l = device_state_callbacks; l != NULL; l = g_slist_next(l)) {
+               struct device_state_callback *cb_data = l->data;
+
+               if (cb_data && cb_data->id == id) {
+                       device_state_callbacks = g_slist_remove(
+                                                       device_state_callbacks,
+                                                       cb_data);
+                       g_free(cb_data);
+                       return true;
+               }
+       }
+
+       return false;
+}

diff --git a/src/device.h b/src/device.h
index 5f615cb4b6b2..a8424aa4f098 100644
--- a/src/device.h
+++ b/src/device.h

@@ -11,8 +11,18 @@

 #define DEVICE_INTERFACE       "org.bluez.Device1"

+enum btd_device_state_t {
+       BTD_DEVICE_STATE_INITIALIZING,  /* Device object is creating */
+       BTD_DEVICE_STATE_AVAILABLE,     /* Device object is registered */
+       BTD_DEVICE_STATE_REMOVING,      /* Device object is being removed */
+};

I got a bad feeling about adding this sort of state, are you trying to
cover some use case that we can't do with btd_service_add_state_cb? It
does seem a lot like it but at device level.

I added this so that the admin plugin can know whenever a device
object is created or removed.
I just learned that we can create a dbus client to listen for new
device objects. If it sounds better, I'll do it in this way.

quoted

+
 struct btd_device;

+typedef void (*btd_device_state_cb) (struct btd_device *device,
+                                       enum btd_device_state_t new_state,
+                                       void *user_data);
+
 struct btd_device *device_create(struct btd_adapter *adapter,
                                const bdaddr_t *address, uint8_t bdaddr_type);
 struct btd_device *device_create_from_storage(struct btd_adapter *adapter,

@@ -179,3 +189,6 @@ bool btd_device_all_services_allowed(struct btd_device *dev);
 void btd_device_update_allowed_services(struct btd_device *dev);
 void btd_device_init(void);
 void btd_device_cleanup(void);
+
+unsigned int btd_device_add_state_cb(btd_device_state_cb cb, void *user_data);
+bool btd_device_remove_state_cb(unsigned int id);
--

2.32.0.93.g670b81a890-goog

--
Luiz Augusto von Dentz