Re: [PATCHv1 3/4] gatt: Add method for creating services in gatt_db

[Szymon Janc <szymon.janc@tieto.com>]

Hi Marcin,

On Wednesday 16 of April 2014 09:19:06 Marcin Kraglak wrote:
> This function will reserve number of handles and create service attribute.
> Primary arguments service type: PRIMARY or SECONDARY.

Info about service type being enum is no longer valid, right?

> ---
>  src/shared/gatt-db.c | 90
> ++++++++++++++++++++++++++++++++++++++++++++++++++++ src/shared/gatt-db.h |
> 14 ++++++++
>  2 files changed, 104 insertions(+)
> 
> diff --git a/src/shared/gatt-db.c b/src/shared/gatt-db.c
> index b057c15..0094616 100644
> --- a/src/shared/gatt-db.c
> +++ b/src/shared/gatt-db.c
> @@ -23,16 +23,26 @@
> 
>  #include <stdbool.h>
> 
> +#include "lib/uuid.h"
>  #include "src/shared/util.h"
>  #include "src/shared/queue.h"
>  #include "src/shared/gatt-db.h"
> 
> +static const bt_uuid_t primary_service_uuid  = { .type = BT_UUID16,

Double space before =.

> +					.value.u16 = GATT_PRIM_SVC_UUID };
> +static const bt_uuid_t secondary_service_uuid  = { .type = BT_UUID16,
> +					.value.u16 = GATT_SND_SVC_UUID };

Same here.

> +
>  struct gatt_db {
>  	uint16_t next_handle;
>  	struct queue *services;
>  };
> 
>  struct gatt_db_attribute {
> +	uint16_t handle;
> +	bt_uuid_t uuid;
> +	uint16_t val_len;
> +	uint8_t value[0];
>  };
> 
>  struct gatt_db_service {
> @@ -76,3 +86,83 @@ void gatt_db_destroy(struct gatt_db *db)
>  	queue_destroy(db->services, gatt_db_service_destroy);
>  	free(db);
>  }
> +
> +static struct gatt_db_attribute *new_attribute(const bt_uuid_t *type,
> +							const uint8_t *val,
> +							uint16_t len)
> +{
> +	struct gatt_db_attribute *attribute;
> +
> +	attribute = malloc0(sizeof(struct gatt_db_attribute) + len);
> +	if (!attribute)
> +		return NULL;
> +
> +	attribute->uuid = *type;
> +	memcpy(&attribute->value, val, len);
> +	attribute->val_len = len;
> +
> +	return attribute;
> +}
> +
> +static int uuid_to_le(const bt_uuid_t *uuid, uint8_t *dst)
> +{
> +	switch (uuid->type) {
> +	case BT_UUID16:
> +		put_le16(uuid->value.u16, dst);
> +		break;
> +	case BT_UUID32:
> +		put_le32(uuid->value.u32, dst);
> +		break;
> +	default:
> +		bswap_128(&uuid->value.u128, dst);
> +		break;
> +	}
> +
> +	return bt_uuid_len(uuid);
> +}
> +
> +uint16_t gatt_db_new_service(struct gatt_db *db, const bt_uuid_t *uuid,
> +					bool primary, uint16_t num_handles)
> +{
> +	struct gatt_db_service *service;
> +	const bt_uuid_t *type;
> +	uint8_t value[16];
> +	uint16_t len;
> +
> +	service = new0(struct gatt_db_service, 1);
> +	if (!service)
> +		return 0;
> +
> +	service->attributes = new0(struct gatt_db_attribute *, num_handles);

This can lead to nasty bug if 0 is passed - note that malloc(0) may return 
valid pointer. Maybe function should fail if 0 is passed? Or ignore
parameter if not >1 ?

> +	if (!service->attributes) {
> +		free(service);
> +		return 0;
> +	}
> +
> +	if (primary)
> +		type = &primary_service_uuid;
> +	else
> +		type = &secondary_service_uuid;
> +
> +	len = uuid_to_le(uuid, value);
> +
> +	service->attributes[0] = new_attribute(type, value, len);
> +	if (!service->attributes[0]) {
> +		gatt_db_service_destroy(service);
> +		return 0;
> +	}
> +
> +	if (!queue_push_tail(db->services, service)) {
> +		gatt_db_service_destroy(service);
> +		return 0;
> +	}
> +
> +	/* TODO now we get next handle from database. We should first look
> +	 * for 'holes' between existing services first, and assign next_handle
> +	 * only if enough space was not found. */
> +	service->attributes[0]->handle = db->next_handle;
> +	db->next_handle += num_handles;
> +	service->num_handles = num_handles;
> +
> +	return service->attributes[0]->handle;
> +}
> diff --git a/src/shared/gatt-db.h b/src/shared/gatt-db.h
> index b3cd7a6..1656bb0 100644
> --- a/src/shared/gatt-db.h
> +++ b/src/shared/gatt-db.h
> @@ -36,3 +36,17 @@ struct gatt_db *gatt_db_new(void);
>   * @db - gatt database to be destroyed
>   */
>  void gatt_db_destroy(struct gatt_db *db);
> +
> +/*
> + * gatt_db_new_service - Add service attribute and reserve number of
> handles + * for this service
> + *
> + * @db - gatt database to add service
> + * @uuid - service uuid
> + * @primary - if service is primary or secondary
> + * @num_handles - num of handles to reserve for service
> + *
> + * Returns handle of service. In case of error 0 is returned.
> + */
> +uint16_t gatt_db_new_service(struct gatt_db *db, const bt_uuid_t *uuid,
> +					bool primary, uint16_t num_handles);

Avoid such doxygen style comments in headers, those tends to diverse when 
implementation is modified. If you want to put comments about num_handles
do it in c file where you allocate memory.

-- 
BR
Szymon Janc