2012-03-21 06:04:09

by Chethan T N

[permalink] [raw]
Subject: [PATCH] avrcp: Handle of GetPlayerApplicationSettingAttributeText pdu

Support for TG role GetPlayerApplicationSettingAttributeText added
to pass PTS test case TP/PAS/BV-04-C
---
audio/avrcp.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 92 insertions(+), 1 deletions(-)

diff --git a/audio/avrcp.c b/audio/avrcp.c
index c9ec314..b09a777 100644
--- a/audio/avrcp.c
+++ b/audio/avrcp.c
@@ -800,6 +800,97 @@ err:
return AVC_CTYPE_REJECTED;
}

+static const char *attr_to_str(uint8_t attr)
+{
+ switch (attr) {
+ case AVRCP_ATTRIBUTE_EQUALIZER:
+ return "Equalizer";
+ case AVRCP_ATTRIBUTE_REPEAT_MODE:
+ return "Repeat";
+ case AVRCP_ATTRIBUTE_SHUFFLE:
+ return "Shuffle";
+ case AVRCP_ATTRIBUTE_SCAN:
+ return "Scan";
+ }
+
+ return NULL;
+}
+
+static uint8_t avrcp_handle_get_player_attribute_text(struct avrcp_player *player,
+ struct avrcp_header *pdu,
+ uint8_t transaction)
+{
+ uint16_t len = ntohs(pdu->params_len);
+ uint8_t *settings = NULL;
+ unsigned int i = 0;
+ uint8_t no_of_attr = 0;
+ const char *attstr = NULL;
+
+ if (player == NULL || len <= 1 || pdu->params[0] != len - 1)
+ goto err;
+
+ /*
+ * Save a copy of requested settings because we can override them
+ * while responding
+ */
+ settings = g_memdup(&pdu->params[1], pdu->params[0]);
+ len = 0;
+
+ /*
+ * From sec. 5.7 of AVRCP 1.3 spec, we should ignore non-existent IDs
+ * and send a response with the existent ones.
+ */
+ for (i = 0; i < pdu->params[0]; i++) {
+
+ if (settings[i] < AVRCP_ATTRIBUTE_EQUALIZER ||
+ settings[i] > AVRCP_ATTRIBUTE_SCAN) {
+ DBG("Ignoring %u", settings[i]);
+ continue;
+ }
+
+ if (player_get_attribute(player, settings[i]) < 0)
+ continue;
+
+ /*
+ * No of attributes that are supported by the player
+ */
+ no_of_attr++;
+ pdu->params[++len] = settings[i];
+
+ /*
+ * As per the MIBenum defined in IANA character set
+ * document the value of displayable UTF-8 charater set
+ * value is 0x006A
+ */
+ pdu->params[++len] = 0x00;
+ pdu->params[++len] = 0x6A;
+ attstr = attr_to_str(settings[i]);
+
+ if (NULL != attstr) {
+ pdu->params[++len] = strlen(attstr);
+ len = len + 1;
+ strncpy((char *) (pdu->params + len), attstr, strlen(attstr));
+ len = len + strlen(attstr);
+ }
+ }
+
+ g_free(settings);
+
+ if (len) {
+ pdu->params[0] = no_of_attr;
+ pdu->params_len = htons(len + 1);
+
+ return AVC_CTYPE_STABLE;
+ }
+
+ error("No valid attributes in request");
+
+err:
+ pdu->params_len = htons(1);
+ pdu->params[0] = E_INVALID_PARAM;
+ return AVC_CTYPE_REJECTED;
+}
+
static uint8_t avrcp_handle_displayable_charset(struct avrcp_player *player,
struct avrcp_header *pdu,
uint8_t transaction)
@@ -1015,7 +1106,7 @@ static struct pdu_handler {
{ AVRCP_SET_PLAYER_VALUE, AVC_CTYPE_CONTROL,
avrcp_handle_set_player_value },
{ AVRCP_GET_PLAYER_ATTRIBUTE_TEXT, AVC_CTYPE_STATUS,
- NULL },
+ avrcp_handle_get_player_attribute_text },
{ AVRCP_GET_PLAYER_VALUE_TEXT, AVC_CTYPE_STATUS,
NULL },
{ AVRCP_DISPLAYABLE_CHARSET, AVC_CTYPE_STATUS,
--
1.7.5.4



2012-03-28 02:47:33

by Chethan T N

[permalink] [raw]
Subject: Re: [PATCH] avrcp: Handle of GetPlayerApplicationSettingAttributeText pdu

Hi,

--------------------------------------------------
From: "Lucas De Marchi" <[email protected]>
Sent: Thursday, March 22, 2012 6:41 AM
To: "Chethan T N" <[email protected]>
Cc: <[email protected]>
Subject: Re: [PATCH] avrcp: Handle of
GetPlayerApplicationSettingAttributeText pdu

> Hi Chethan,
>
> On Wed, Mar 21, 2012 at 3:04 AM, Chethan T N <[email protected]>
> wrote:
>> Support for TG role GetPlayerApplicationSettingAttributeText added
>> to pass PTS test case TP/PAS/BV-04-C
>> ---
>> audio/avrcp.c | 93
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>> 1 files changed, 92 insertions(+), 1 deletions(-)
>
> I started reviewing this and it looked very familiar to me, including
> the comments... It turned out that this implementation is very similar
> to avrcp_handle_get_current_player_value() and then it made me wonder
> why I didn't implement it last year. See comment below.
>
>
>>
>> diff --git a/audio/avrcp.c b/audio/avrcp.c
>> index c9ec314..b09a777 100644
>> --- a/audio/avrcp.c
>> +++ b/audio/avrcp.c
>> @@ -800,6 +800,97 @@ err:
>> return AVC_CTYPE_REJECTED;
>> }
>>
>> +static const char *attr_to_str(uint8_t attr)
>> +{
>> + switch (attr) {
>> + case AVRCP_ATTRIBUTE_EQUALIZER:
>> + return "Equalizer";
>> + case AVRCP_ATTRIBUTE_REPEAT_MODE:
>> + return "Repeat";
>> + case AVRCP_ATTRIBUTE_SHUFFLE:
>> + return "Shuffle";
>> + case AVRCP_ATTRIBUTE_SCAN:
>> + return "Scan";
>> + }
>> +
>> + return NULL;
>> +}
>
> We can't have these values hardcoded here. CT is asking the TG: "what
> should I display in my pane?" - it's meaningless to answer this since
> CT already knows that for the settings from the spec.
>

ok. I agree for the default settings like Equalizer, Shuffle, Repeat and
Scan values TG need
not to send to CT.

> See section 5.2.5 of AVRCP 1.3 spec:
>
> "NOTE: This command is expected to be used only for extended attributes
> for menu
> navigation. It is assumed that all <attribute, value> pairs used for
> menu extensions are
> statically defined by TG."
>

ok, But the <attribute, value> pair for extended attributes may vary for
different TG's.
So TG application register their extended attributes to bluez, and when CT
requests for
these values TG shall send the <attribute, value> based on the attribute ID.

> Therefore we should only implement that for settings that extend the
> "default ones". If you want that, take a look in the comments below
> (besides having to extend the current API for getting values, etc).
>
>
>> +
>> +static uint8_t avrcp_handle_get_player_attribute_text(struct
>> avrcp_player *player,
>> + struct avrcp_header *pdu,
>> + uint8_t transaction)
>> +{
>> + uint16_t len = ntohs(pdu->params_len);
>> + uint8_t *settings = NULL;
>> + unsigned int i = 0;
>> + uint8_t no_of_attr = 0;
>> + const char *attstr = NULL;
>
> Review useless initialization...

I will modify the initializations.
>
>
>> +
>> + if (player == NULL || len <= 1 || pdu->params[0] != len - 1)
>> + goto err;
>> +
>> + /*
>> + * Save a copy of requested settings because we can override them
>> + * while responding
>> + */
>> + settings = g_memdup(&pdu->params[1], pdu->params[0]);
>> + len = 0;
>> +
>> + /*
>> + * From sec. 5.7 of AVRCP 1.3 spec, we should ignore non-existent
>> IDs
>> + * and send a response with the existent ones.
>> + */
>> + for (i = 0; i < pdu->params[0]; i++) {
>> +
>> + if (settings[i] < AVRCP_ATTRIBUTE_EQUALIZER ||
>> + settings[i] >
>> AVRCP_ATTRIBUTE_SCAN) {
>> + DBG("Ignoring %u", settings[i]);
>> + continue;
>> + }
>
> We would change this loop and pass the setting to player.

ok.

>
>> +
>> + if (player_get_attribute(player, settings[i]) < 0)
>> + continue;
>
> You are asking the value of that setting to the player only to know if
> player supports that setting. But you actually have to respond with
> the _name_ of the key. Pretty confusing here. We should ask the _name_
> of the key, not its value.

ok, I will modify based on the _name_.
>
>> +
>> + /*
>> + * No of attributes that are supported by the player
>> + */
>> + no_of_attr++;
>> + pdu->params[++len] = settings[i];
>> +
>> + /*
>> + * As per the MIBenum defined in IANA character set
>> + * document the value of displayable UTF-8 charater set
>> + * value is 0x006A
>> + */
>> + pdu->params[++len] = 0x00;
>> + pdu->params[++len] = 0x6A;
>> + attstr = attr_to_str(settings[i]);
>> +
>> + if (NULL != attstr) {
> reverse order...
>
> and you already incremented no_of_attr, CT will be very confused

ok, I will modify the increment of no_of_attr after copying the _name_.

>
>> + pdu->params[++len] = strlen(attstr);
>
> 1
>
>> + len = len + 1;
>> + strncpy((char *) (pdu->params + len), attstr,
>> strlen(attstr));
>
> 2
>
>> + len = len + strlen(attstr);
>
> 3
>
> 3 calls to strlen() ( + 1 inside strncpy()).... not good - cache it in
> variable and use that instead (in this case it could even be hardcoded
> in attr_to_str(), but this can't be as is because of the first comment
> above..
>

ok. I will modify.

>
> Regards,
> Lucas De Marchi


Thanks and Regards
Chethan


2012-03-22 01:11:20

by Lucas De Marchi

[permalink] [raw]
Subject: Re: [PATCH] avrcp: Handle of GetPlayerApplicationSettingAttributeText pdu

Hi Chethan,

On Wed, Mar 21, 2012 at 3:04 AM, Chethan T N <[email protected]> wrote:
> Support for TG role GetPlayerApplicationSettingAttributeText added
> to pass PTS test case TP/PAS/BV-04-C
> ---
> ?audio/avrcp.c | ? 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> ?1 files changed, 92 insertions(+), 1 deletions(-)

I started reviewing this and it looked very familiar to me, including
the comments... It turned out that this implementation is very similar
to avrcp_handle_get_current_player_value() and then it made me wonder
why I didn't implement it last year. See comment below.


>
> diff --git a/audio/avrcp.c b/audio/avrcp.c
> index c9ec314..b09a777 100644
> --- a/audio/avrcp.c
> +++ b/audio/avrcp.c
> @@ -800,6 +800,97 @@ err:
> ? ? ? ?return AVC_CTYPE_REJECTED;
> ?}
>
> +static const char *attr_to_str(uint8_t attr)
> +{
> + ? ? ? switch (attr) {
> + ? ? ? case AVRCP_ATTRIBUTE_EQUALIZER:
> + ? ? ? ? ? ? ? return "Equalizer";
> + ? ? ? case AVRCP_ATTRIBUTE_REPEAT_MODE:
> + ? ? ? ? ? ? ? return "Repeat";
> + ? ? ? case AVRCP_ATTRIBUTE_SHUFFLE:
> + ? ? ? ? ? ? ? return "Shuffle";
> + ? ? ? case AVRCP_ATTRIBUTE_SCAN:
> + ? ? ? ? ? ? ? return "Scan";
> + ? ? ? }
> +
> + ? ? ? return NULL;
> +}

We can't have these values hardcoded here. CT is asking the TG: "what
should I display in my pane?" - it's meaningless to answer this since
CT already knows that for the settings from the spec.

See section 5.2.5 of AVRCP 1.3 spec:

"NOTE: This command is expected to be used only for extended attributes for menu
navigation. It is assumed that all <attribute, value> pairs used for
menu extensions are
statically defined by TG."

Therefore we should only implement that for settings that extend the
"default ones". If you want that, take a look in the comments below
(besides having to extend the current API for getting values, etc).


> +
> +static uint8_t avrcp_handle_get_player_attribute_text(struct avrcp_player *player,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct avrcp_header *pdu,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? uint8_t transaction)
> +{
> + ? ? ? uint16_t len = ntohs(pdu->params_len);
> + ? ? ? uint8_t *settings = NULL;
> + ? ? ? unsigned int i = 0;
> + ? ? ? uint8_t no_of_attr = 0;
> + ? ? ? const char *attstr = NULL;

Review useless initialization...


> +
> + ? ? ? if (player == NULL || len <= 1 || pdu->params[0] != len - 1)
> + ? ? ? ? ? ? ? goto err;
> +
> + ? ? ? /*
> + ? ? ? ?* Save a copy of requested settings because we can override them
> + ? ? ? ?* while responding
> + ? ? ? ?*/
> + ? ? ? settings = g_memdup(&pdu->params[1], pdu->params[0]);
> + ? ? ? len = 0;
> +
> + ? ? ? /*
> + ? ? ? ?* From sec. 5.7 of AVRCP 1.3 spec, we should ignore non-existent IDs
> + ? ? ? ?* and send a response with the existent ones.
> + ? ? ? ?*/
> + ? ? ? for (i = 0; i < pdu->params[0]; i++) {
> +
> + ? ? ? ? ? ? ? if (settings[i] < AVRCP_ATTRIBUTE_EQUALIZER ||
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? settings[i] > AVRCP_ATTRIBUTE_SCAN) {
> + ? ? ? ? ? ? ? ? ? ? ? DBG("Ignoring %u", settings[i]);
> + ? ? ? ? ? ? ? ? ? ? ? continue;
> + ? ? ? ? ? ? ? }

We would change this loop and pass the setting to player.

> +
> + ? ? ? ? ? ? ? if (player_get_attribute(player, settings[i]) < 0)
> + ? ? ? ? ? ? ? ? ? ? ? continue;

You are asking the value of that setting to the player only to know if
player supports that setting. But you actually have to respond with
the _name_ of the key. Pretty confusing here. We should ask the _name_
of the key, not its value.

> +
> + ? ? ? ? ? ? ? /*
> + ? ? ? ? ? ? ? ?* No of attributes that are supported by the player
> + ? ? ? ? ? ? ? ?*/
> + ? ? ? ? ? ? ? no_of_attr++;
> + ? ? ? ? ? ? ? pdu->params[++len] = settings[i];
> +
> + ? ? ? ? ? ? ? /*
> + ? ? ? ? ? ? ? ?* As per the MIBenum defined in IANA character set
> + ? ? ? ? ? ? ? ?* document the value of displayable UTF-8 charater set
> + ? ? ? ? ? ? ? ?* value is 0x006A
> + ? ? ? ? ? ? ? ?*/
> + ? ? ? ? ? ? ? pdu->params[++len] = 0x00;
> + ? ? ? ? ? ? ? pdu->params[++len] = 0x6A;
> + ? ? ? ? ? ? ? attstr = attr_to_str(settings[i]);
> +
> + ? ? ? ? ? ? ? if (NULL != attstr) {
reverse order...

and you already incremented no_of_attr, CT will be very confused

> + ? ? ? ? ? ? ? ? ? ? ? pdu->params[++len] = strlen(attstr);

1

> + ? ? ? ? ? ? ? ? ? ? ? len = len + 1;
> + ? ? ? ? ? ? ? ? ? ? ? strncpy((char *) (pdu->params + len), attstr, strlen(attstr));

2

> + ? ? ? ? ? ? ? ? ? ? ? len = len + strlen(attstr);

3

3 calls to strlen() ( + 1 inside strncpy()).... not good - cache it in
variable and use that instead (in this case it could even be hardcoded
in attr_to_str(), but this can't be as is because of the first comment
above..


Regards,
Lucas De Marchi