shared/gatt-client: Read database hash if available

This reads the database hash if available and compares to the existing
value, if it matches consider the discovery is completed.

Change-Id: I5dabc14550049afe4bc1e4c6ab790cd2d25e57e2
Signed-off-by: himanshu <h.himanshu@samsung.com>

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index c824530..30e4a57 100644 (file)
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -354,6 +354,7 @@ struct discovery_op {
        struct queue *pending_chrcs;
        struct queue *ext_prop_desc;
        struct gatt_db_attribute *cur_svc;
+       struct gatt_db_attribute *hash;
        bool success;
        uint16_t start;
        uint16_t end;
@@ -378,12 +379,20 @@ static void discovery_op_free(struct discovery_op *op)
        free(op);
 }
 
+static bool read_db_hash(struct discovery_op *op);
+
 static void discovery_op_complete(struct discovery_op *op, bool success,
                                                                uint8_t err)
 {
 #ifdef TIZEN_FEATURE_BLUEZ_MODIFY
        const struct queue_entry *svc;
 
+       op->success = success;
+
+       /* Read database hash if discovery has been successful */
+       if (success && read_db_hash(op))
+               return;
+
        /*
         * Unregister remove callback so it is not called when clearing unused
         * range.
@@ -434,7 +443,6 @@ static void discovery_op_complete(struct discovery_op *op, bool success,
        if (op->last != UINT16_MAX)
                gatt_db_clear_range(op->client->db, op->last + 1, UINT16_MAX);
 
-       op->success = success;
        op->complete_func(op, success, err);
 #endif
 }
@@ -1387,6 +1395,139 @@ static void notify_client_ready(struct bt_gatt_client *client, bool success,
        bt_gatt_client_unref(client);
 }
 
+static void discover_all(struct discovery_op *op)
+{
+       struct bt_gatt_client *client = op->client;
+
+       client->discovery_req = bt_gatt_discover_all_primary_services(
+                                                       client->att, NULL,
+                                                       discover_primary_cb,
+                                                       discovery_op_ref(op),
+                                                       discovery_op_unref);
+       if (client->discovery_req)
+               return;
+
+       util_debug(client->debug_callback, client->debug_data,
+                       "Failed to initiate primary service discovery");
+
+       client->in_init = false;
+       notify_client_ready(client, false, BT_ATT_ERROR_UNLIKELY);
+
+       discovery_op_unref(op);
+}
+
+static void db_hash_write_value_cb(struct gatt_db_attribute *attrib,
+                                               int err, void *user_data)
+{
+       struct bt_gatt_client *client = user_data;
+
+       util_debug(client->debug_callback, client->debug_data,
+                                               "Value set status: %d", err);
+}
+
+static void db_hash_read_value_cb(struct gatt_db_attribute *attrib,
+                                               int err, const uint8_t *value,
+                                               size_t length, void *user_data)
+{
+       const uint8_t **hash = user_data;
+
+       if (err || (length != 16))
+               return;
+
+       *hash = value;
+}
+
+static void db_hash_read_cb(bool success, uint8_t att_ecode,
+                                               struct bt_gatt_result *result,
+                                               void *user_data)
+{
+       struct discovery_op *op = user_data;
+       struct bt_gatt_client *client = op->client;
+       const uint8_t *hash = NULL, *value;
+       uint16_t len, handle;
+       struct bt_gatt_iter iter;
+
+       if (!success)
+               goto discover;
+
+       bt_gatt_iter_init(&iter, result);
+       bt_gatt_iter_next_read_by_type(&iter, &handle, &len, &value);
+
+       util_debug(client->debug_callback, client->debug_data,
+                               "DB Hash found: handle 0x%04x length 0x%04x",
+                               handle, len);
+
+       if (len != 16)
+               goto discover;
+
+       /* Read stored value in the db */
+       gatt_db_attribute_read(op->hash, 0, BT_ATT_OP_READ_REQ, NULL,
+                                       db_hash_read_value_cb, &hash);
+
+       /* Check if the has has changed since last time */
+       if (hash && !memcmp(hash, value, len)) {
+               util_debug(client->debug_callback, client->debug_data,
+                               "DB Hash match: skipping discovery");
+               queue_remove_all(op->pending_svcs, NULL, NULL, NULL);
+               discovery_op_complete(op, true, 0);
+               return;
+       }
+
+       util_debug(client->debug_callback, client->debug_data,
+                                               "DB Hash value:");
+       util_hexdump(' ', value, len, client->debug_callback,
+                                               client->debug_data);
+
+       /* Store the new hash in the db */
+       gatt_db_attribute_write(op->hash, 0, value, len, 0, NULL,
+                                       db_hash_write_value_cb, client);
+
+discover:
+       if (!op->success) {
+               discover_all(op);
+               return;
+       }
+
+       discovery_op_complete(op, true, 0);
+}
+
+static void get_first_attribute(struct gatt_db_attribute *attrib,
+                                                               void *user_data)
+{
+       struct gatt_db_attribute **stored = user_data;
+
+       if (*stored)
+               return;
+
+       *stored = attrib;
+}
+
+static bool read_db_hash(struct discovery_op *op)
+{
+       struct bt_gatt_client *client = op->client;
+       bt_uuid_t uuid;
+
+       /* Check if hash was already read */
+       if (op->hash)
+               return false;
+
+       bt_uuid16_create(&uuid, GATT_CHARAC_DB_HASH);
+       gatt_db_find_by_type(client->db, 0x0001, 0xffff, &uuid,
+                                               get_first_attribute, &op->hash);
+       if (!op->hash)
+               return false;
+
+       if (!bt_gatt_read_by_type(client->att, 0x0001, 0xffff, &uuid,
+                                                       db_hash_read_cb,
+                                                       discovery_op_ref(op),
+                                                       discovery_op_unref)) {
+               discovery_op_unref(op);
+               return false;
+       }
+
+       return true;
+}
+
 static void exchange_mtu_cb(bool success, uint8_t att_ecode, void *user_data)
 {
        struct discovery_op *op = user_data;
@@ -1423,21 +1564,12 @@ discover:
 #ifdef TIZEN_FEATURE_BLUEZ_MODIFY
        op->success = false;
 #endif
-       client->discovery_req = bt_gatt_discover_all_primary_services(
-                                                       client->att, NULL,
-                                                       discover_primary_cb,
-                                                       discovery_op_ref(op),
-                                                       discovery_op_unref);
-       if (client->discovery_req)
-               return;
-
-       util_debug(client->debug_callback, client->debug_data,
-                       "Failed to initiate primary service discovery");
-
-       client->in_init = false;
-       notify_client_ready(client, false, att_ecode);
+       if (read_db_hash(op)) {
+               op->success = false;
+               return;
+       }
 
-       discovery_op_unref(op);
+       discover_all(op);
 }
 
 struct service_changed_op {
@@ -1659,17 +1791,6 @@ static unsigned int register_notify(struct bt_gatt_client *client,
        return notify_data->id;
 }
 
-static void get_first_attribute(struct gatt_db_attribute *attrib,
-                                                               void *user_data)
-{
-       struct gatt_db_attribute **stored = user_data;
-
-       if (*stored)
-               return;
-
-       *stored = attrib;
-}
-
 static void service_changed_register_cb(uint16_t att_ecode, void *user_data)
 {
        bool success;
@@ -1963,6 +2084,11 @@ static bool gatt_client_init(struct bt_gatt_client *client, uint16_t mtu)
        return true;
 
 discover:
+       if (read_db_hash(op)) {
+               op->success = false;
+               goto done;
+       }
+
        client->discovery_req = bt_gatt_discover_all_primary_services(
                                                        client->att, NULL,
                                                        discover_primary_cb,
@@ -1973,6 +2099,7 @@ discover:
                return false;
        }
 
+done:
        client->in_init = true;
        return true;
 }