Re: [PATCH BlueZ 03/16] android/avrcp-lib: Rework handler callback parameters

[Andrei Emeltchenko <andrei.emeltchenko.news@gmail.com>]

Hi Luiz,

On Sun, Mar 02, 2014 at 08:48:18PM +0200, Luiz Augusto von Dentz wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> This rework handler callback parameters to make it able to return
> proper error such as -EAGAIN to implement asynchronous responses.
> ---
>  android/avrcp-lib.c | 12 +++++++++---
>  android/avrcp-lib.h |  5 +++--
>  unit/test-avrcp.c   | 42 +++++++++++++++++++++---------------------
>  3 files changed, 33 insertions(+), 26 deletions(-)
> 
> diff --git a/android/avrcp-lib.c b/android/avrcp-lib.c
> index cdad6ac..339be16 100644
> --- a/android/avrcp-lib.c
> +++ b/android/avrcp-lib.c
> @@ -125,6 +125,7 @@ static ssize_t handle_vendordep_pdu(struct avctp *conn, uint8_t transaction,
>  	struct avrcp_header *pdu = (void *) operands;
>  	uint32_t company_id = ntoh24(pdu->company_id);
>  	uint16_t params_len = ntohs(pdu->params_len);
> +	ssize_t ret;
>  
>  	if (company_id != IEEEID_BTSIG) {
>  		*code = AVC_CTYPE_NOT_IMPLEMENTED;
> @@ -159,12 +160,17 @@ static ssize_t handle_vendordep_pdu(struct avctp *conn, uint8_t transaction,
>  		goto reject;
>  	}
>  
> -	*code = handler->func(session, transaction, &params_len,
> +	ret = handler->func(session, transaction, code, params_len,
>  					pdu->params, session->control_data);
> +	if (ret < 0) {
> +		if (ret == -EAGAIN)
> +			return ret;
> +		goto reject;
> +	}
>  
> -	pdu->params_len = htons(params_len);
> +	pdu->params_len = htons(ret);
>  
> -	return AVRCP_HEADER_LENGTH + params_len;
> +	return AVRCP_HEADER_LENGTH + ret;
>  
>  reject:
>  	pdu->params_len = htons(1);
> diff --git a/android/avrcp-lib.h b/android/avrcp-lib.h
> index a33bdfe..d7a805b 100644
> --- a/android/avrcp-lib.h
> +++ b/android/avrcp-lib.h
> @@ -79,8 +79,9 @@ struct avrcp;
>  struct avrcp_control_handler {
>  	uint8_t id;
>  	uint8_t code;
> -	uint8_t (*func) (struct avrcp *session, uint8_t transaction,
> -			uint16_t *params_len, uint8_t *params, void *user_data);
> +	ssize_t (*func) (struct avrcp *session, uint8_t transaction,
> +			uint8_t *code, uint16_t params_len, uint8_t *params,
> +			void *user_data);
>  };
>  
>  struct avrcp_passthrough_handler {
> diff --git a/unit/test-avrcp.c b/unit/test-avrcp.c
> index 302c331..2d5711b 100644
> --- a/unit/test-avrcp.c
> +++ b/unit/test-avrcp.c
> @@ -292,54 +292,54 @@ static const struct avrcp_passthrough_handler passthrough_handlers[] = {
>  		{ },
>  };
>  
> -static uint8_t avrcp_handle_get_capabilities(struct avrcp *session,
> -				uint8_t transaction, uint16_t *params_len,
> -				uint8_t *params, void *user_data)
> +static ssize_t avrcp_handle_get_capabilities(struct avrcp *session,
> +					uint8_t transaction, uint8_t *code,
> +					uint16_t params_len, uint8_t *params,
> +					void *user_data)
>  {
>  	uint32_t id = 0x001958;
>  
> -	DBG("params[0] %d params_len %d", params[0], *params_len);
> -
> -	if (*params_len != 1)
> +	if (params_len != 1)
>  		goto fail;
>  
>  	switch (params[0]) {
>  	case CAP_COMPANY_ID:
> -		*params_len = 5;
>  		params[1] = 1;
>  		hton24(&params[2], id);
> -		return AVC_CTYPE_STABLE;
> +		*code = AVC_CTYPE_STABLE;
> +		return 5;

What is 5? Shall we define constants or use formulas?

Best regards 
Andrei Emeltchenko