[RFC] API for MAP client in obex-client

[RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

Hi,
below proposed API for MAP client in obex-client, for now just some
generic functions and browsing support.

Messages Access hierarchy
=========================

Service         org.openobex.client
Interface       org.openobex.MessagesAccess
Object path     [variable prefix]/{session0,session1,...}

Methods         dict(uint8 tag, variant value) GetAppParams()

                       Retrieve application parameters connected to the last MSE
                       response. Application parameters corresponding
to given call
                       are accessible until next request is sent.

                       Parameters are converted to unsigned integers
of corresponding sizes
                       (MAP specification section 6.3.1) or
NULL-terminated strings.
                       In case of parameters not mentioned in MAP
specification value
                       becomes struct of (uint8 length, array{uint8}).

                       See MAP specification (section corresponding to
given function)
                       for more details on returned parameters.

               void SetFolder(boolean cdup, string name)

                       Set working directory for current session.

                       |  cdup  | folder name | operation    |
                       |=====================================|
                       | FALSE  | empty       | cd /         |
                       |--------+-------------+--------------|
                       | FALSE  | name        | cd name      |
                       |--------+-------------+--------------|
                       | TRUE   | [name]      | cd ..[/name] |
                       +-------------------------------------+

               array{dict(string property, string value)}
               GetFolderListing(dict(uint8 tag, uint16 value))

                       Retrieve list of names (and all other
properties returned by MSE)
                       for directories in CWD.

                       Parameters as in MAP specification section 5.4.

               array{dict(string property, string value)}
               GetMessageListing(string folder, array{uint8 tag, variant value})

                       Return message listing for given subfolder of
CWD or directly
                       CWD if folder field is empty, format of each dict entry
                       corresponds to the message listing format (MAP
specification
                       section 3.1.6).

                       Parameters as in MAP specification section 5.5.

               unix_fd msgfd
               GetMessage(string handle, dict(uint8 tag, variant value))

                       Retrieve message from remote device and return
file descriptor,
                       from which message data (in BMSG format) may be read.

                       Parameters as in MAP specification section 5.6.

               void SetMessageStatus(string handle, uint8 indicator,
uint8 value)

                       Modify status of a message on remote device.

                       Parameters as in MAP specification section 5.7.

               void UpdateInbox()

                       Initiate update of inbox status on remote device.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Hendrik Sattler]

Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
> Hi,
> below proposed API for MAP client in obex-client, for now just some
> generic functions and browsing support.
>
> Messages Access hierarchy
> =========================
>
> Service         org.openobex.client
> Interface       org.openobex.MessagesAccess

Are there any plan on switching to a different namespace?
Using openobex was always in conflict with previously existing software 
(o-d-s) and with the switch to gobex for the client, it's even less 
correct.

HS

[RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

Hi,
below proposed API for MAP client in obex-client, for now just some
generic functions and browsing support.

Messages Access hierarchy
=========================

Service		org.openobex.client
Interface	org.openobex.MessagesAccess
Object path	[variable prefix]/{session0,session1,...}

Methods		dict(uint8 tag, variant value) GetAppParams()

			Retrieve application parameters connected to the last MSE 
			response. Application parameters corresponding to given call
			are accessible until next request is sent.

			Parameters are converted to unsigned integers of corresponding sizes
			(MAP specification section 6.3.1) or NULL-terminated strings.
			In case of parameters not mentioned in MAP specification value 
			becomes struct of (uint8 length, array{uint8}).

			See MAP specification (section corresponding to given function)
			for more details on returned parameters.

		void SetFolder(boolean cdup, string name)

			Set working directory for current session.

			|  cdup  | folder name | operation    | 
			|=====================================|
			| FALSE  | empty       | cd /         |
			|--------+-------------+--------------|
			| FALSE  | name        | cd name      |
			|--------+-------------+--------------|
			| TRUE   | [name]      | cd ..[/name] |
			+-------------------------------------+

		array{dict(string property, string value)}
		GetFolderListing(dict(uint8 tag, uint16 value))

			Retrieve list of names (and all other properties returned by MSE)
			for directories in CWD.

			Parameters as in MAP specification section 5.4.

		array{dict(string property, string value)}
		GetMessageListing(string folder, array{uint8 tag, variant value})

			Return message listing for given subfolder of CWD or directly
			CWD if folder field is empty, format of each dict entry
			corresponds to the message listing format (MAP specification
			section 3.1.6).

			Parameters as in MAP specification section 5.5.

		unix_fd msgfd
		GetMessage(string handle, dict(uint8 tag, variant value))

			Retrieve message from remote device and return file descriptor,
			from which message data (in BMSG format) may be read.

			Parameters as in MAP specification section 5.6.

		void SetMessageStatus(string handle, uint8 indicator, uint8 value)

			Modify status of a message on remote device.

			Parameters as in MAP specification section 5.7.

		void UpdateInbox()

			Initiate update of inbox status on remote device.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Hendrik Sattler]

Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>                void SetFolder(boolean cdup, string name)
>
>                        Set working directory for current session.
>
>                        |  cdup  | folder name | operation    |
>                        |=====================================|
>                        | FALSE  | empty       | cd /         |
>                        |--------+-------------+--------------|
>                        | FALSE  | name        | cd name      |
>                        |--------+-------------+--------------|
>                        | TRUE   | [name]      | cd ..[/name] |
>                        +-------------------------------------+

Why not simply
   void SetFolder(String cdString)

and derive the obex command from that? It makes that API much easier to 
use.

HS

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

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Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Thu, Nov 3, 2011 at 4:16 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
> On Thu, Nov 3, 2011 at 3:08 PM, Hendrik Sattler <post@hendrik-sattler.de> wrote:
>> Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>>>
>>>               void SetFolder(boolean cdup, string name)
>>>
>>>                       Set working directory for current session.
>>>
>>>                       |  cdup  | folder name | operation    |
>>>                       |=====================================|
>>>                       | FALSE  | empty       | cd /         |
>>>                       |--------+-------------+--------------|
>>>                       | FALSE  | name        | cd name      |
>>>                       |--------+-------------+--------------|
>>>                       | TRUE   | [name]      | cd ..[/name] |
>>>                       +-------------------------------------+
>>
>> Why not simply
>>  void SetFolder(String cdString)
>>
>> and derive the obex command from that? It makes that API much easier to use.
>>
>> HS
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
>> in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
> Because it provoke more questions eg. what about failure in the middle
> of the path? Also i've planned to keep it at rather low level.

Well we can make it only accept only one step at time, which it seems
is what g_obex_setpath does. Btw what is thing with GetMessage return,
fd? Do we really need that? Can't we just convert to string so that
user applications don't have to convert it themselves? Otherwise just
use an array of bytes ('ay') or pass a path where the message should
be stored like GetFile. If the concern is that the transfer may take
too long the client the client should not wait the reply and instead
track the transfer using an agent.

-- 
Luiz Augusto von Dentz

Re: [RFC] API for MAP client in obex-client

[Anders Widen]

Hi!

This API is directly linked to the MAP Specification for setFolder see
P.49. Therefor it's already documented and easier to understand.

2011/11/3 Luiz Augusto von Dentz <luiz.dentz@gmail.com>:
> Hi Bartosz,
>
> On Thu, Nov 3, 2011 at 4:16 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>> On Thu, Nov 3, 2011 at 3:08 PM, Hendrik Sattler <post@hendrik-sattler.de> wrote:
>>> Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>>>>
>>>>               void SetFolder(boolean cdup, string name)
>>>>
>>>>                       Set working directory for current session.
>>>>
>>>>                       |  cdup  | folder name | operation    |
>>>>                       |=====================================|
>>>>                       | FALSE  | empty       | cd /         |
>>>>                       |--------+-------------+--------------|
>>>>                       | FALSE  | name        | cd name      |
>>>>                       |--------+-------------+--------------|
>>>>                       | TRUE   | [name]      | cd ..[/name] |
>>>>                       +-------------------------------------+
>>>
>>> Why not simply
>>>  void SetFolder(String cdString)
>>>
>>> and derive the obex command from that? It makes that API much easier to use.
>>>
>>> HS
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
>>> in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>> Because it provoke more questions eg. what about failure in the middle
>> of the path? Also i've planned to keep it at rather low level.
>
> Well we can make it only accept only one step at time, which it seems
> is what g_obex_setpath does. Btw what is thing with GetMessage return,
> fd? Do we really need that? Can't we just convert to string so that
> user applications don't have to convert it themselves? Otherwise just
> use an array of bytes ('ay') or pass a path where the message should
> be stored like GetFile. If the concern is that the transfer may take
> too long the client the client should not wait the reply and instead
> track the transfer using an agent.
>
> --
> Luiz Augusto von Dentz
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

On Thu, Nov 3, 2011 at 4:13 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Bartosz,
>
> On Thu, Nov 3, 2011 at 4:16 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>> On Thu, Nov 3, 2011 at 3:08 PM, Hendrik Sattler <post@hendrik-sattler.de> wrote:
>>> Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>>>>
>>>>               void SetFolder(boolean cdup, string name)
>>>>
>>>>                       Set working directory for current session.
>>>>
>>>>                       |  cdup  | folder name | operation    |
>>>>                       |=====================================|
>>>>                       | FALSE  | empty       | cd /         |
>>>>                       |--------+-------------+--------------|
>>>>                       | FALSE  | name        | cd name      |
>>>>                       |--------+-------------+--------------|
>>>>                       | TRUE   | [name]      | cd ..[/name] |
>>>>                       +-------------------------------------+
>>>
>>> Why not simply
>>>  void SetFolder(String cdString)
>>>
>>> and derive the obex command from that? It makes that API much easier to use.
>>>
>>> HS
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
>>> in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
>> Because it provoke more questions eg. what about failure in the middle
>> of the path? Also i've planned to keep it at rather low level.
>
> Well we can make it only accept only one step at time, which it seems
> is what g_obex_setpath does. Btw what is thing with GetMessage return,
> fd? Do we really need that? Can't we just convert to string so that
> user applications don't have to convert it themselves? Otherwise just
> use an array of bytes ('ay') or pass a path where the message should
> be stored like GetFile. If the concern is that the transfer may take
> too long the client the client should not wait the reply and instead
> track the transfer using an agent.
>
> --
> Luiz Augusto von Dentz
>

And what if you'll start downloading email with 10MB attachment?? So
it's better to send file descriptor through DBus than lots (and lots)
of data. And there is nothing to convert, client will get fd and then
just read message from a file - it's simple enough.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Thu, Nov 3, 2011 at 7:38 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
> On Thu, Nov 3, 2011 at 4:13 PM, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
>> Hi Bartosz,
>>
>> On Thu, Nov 3, 2011 at 4:16 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>> On Thu, Nov 3, 2011 at 3:08 PM, Hendrik Sattler <post@hendrik-sattler.de> wrote:
>>>> Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>>>>>
>>>>>               void SetFolder(boolean cdup, string name)
>>>>>
>>>>>                       Set working directory for current session.
>>>>>
>>>>>                       |  cdup  | folder name | operation    |
>>>>>                       |=====================================|
>>>>>                       | FALSE  | empty       | cd /         |
>>>>>                       |--------+-------------+--------------|
>>>>>                       | FALSE  | name        | cd name      |
>>>>>                       |--------+-------------+--------------|
>>>>>                       | TRUE   | [name]      | cd ..[/name] |
>>>>>                       +-------------------------------------+
>>>>
>>>> Why not simply
>>>>  void SetFolder(String cdString)
>>>>
>>>> and derive the obex command from that? It makes that API much easier to use.
>>>>
>>>> HS
>>>>
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
>>>> in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>
>>> Because it provoke more questions eg. what about failure in the middle
>>> of the path? Also i've planned to keep it at rather low level.
>>
>> Well we can make it only accept only one step at time, which it seems
>> is what g_obex_setpath does. Btw what is thing with GetMessage return,
>> fd? Do we really need that? Can't we just convert to string so that
>> user applications don't have to convert it themselves? Otherwise just
>> use an array of bytes ('ay') or pass a path where the message should
>> be stored like GetFile. If the concern is that the transfer may take
>> too long the client the client should not wait the reply and instead
>> track the transfer using an agent.
>>
>> --
>> Luiz Augusto von Dentz
>>
>
> And what if you'll start downloading email with 10MB attachment?? So
> it's better to send file descriptor through DBus than lots (and lots)
> of data. And there is nothing to convert, client will get fd and then
> just read message from a file - it's simple enough.

Then create a transfer object and notify the agent like we do for
GetFile, also with this you progress indication like we have with
normal files and you are also able to catch errors or cancel the
transfer.

-- 
Luiz Augusto von Dentz

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

On Thu, Nov 3, 2011 at 6:59 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Bartosz,
>
> On Thu, Nov 3, 2011 at 7:38 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>> On Thu, Nov 3, 2011 at 4:13 PM, Luiz Augusto von Dentz
>> <luiz.dentz@gmail.com> wrote:
>>> Hi Bartosz,
>>>
>>> On Thu, Nov 3, 2011 at 4:16 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>> On Thu, Nov 3, 2011 at 3:08 PM, Hendrik Sattler <post@hendrik-sattler.de> wrote:
>>>>> Am 03.11.2011 14:44, schrieb Bartosz Szatkowski:
>>>>>>
>>>>>>               void SetFolder(boolean cdup, string name)
>>>>>>
>>>>>>                       Set working directory for current session.
>>>>>>
>>>>>>                       |  cdup  | folder name | operation    |
>>>>>>                       |=====================================|
>>>>>>                       | FALSE  | empty       | cd /         |
>>>>>>                       |--------+-------------+--------------|
>>>>>>                       | FALSE  | name        | cd name      |
>>>>>>                       |--------+-------------+--------------|
>>>>>>                       | TRUE   | [name]      | cd ..[/name] |
>>>>>>                       +-------------------------------------+
>>>>>
>>>>> Why not simply
>>>>>  void SetFolder(String cdString)
>>>>>
>>>>> and derive the obex command from that? It makes that API much easier to use.
>>>>>
>>>>> HS
>>>>>
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth"
>>>>> in
>>>>> the body of a message to majordomo@vger.kernel.org
>>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>>
>>>>
>>>> Because it provoke more questions eg. what about failure in the middle
>>>> of the path? Also i've planned to keep it at rather low level.
>>>
>>> Well we can make it only accept only one step at time, which it seems
>>> is what g_obex_setpath does. Btw what is thing with GetMessage return,
>>> fd? Do we really need that? Can't we just convert to string so that
>>> user applications don't have to convert it themselves? Otherwise just
>>> use an array of bytes ('ay') or pass a path where the message should
>>> be stored like GetFile. If the concern is that the transfer may take
>>> too long the client the client should not wait the reply and instead
>>> track the transfer using an agent.
>>>
>>> --
>>> Luiz Augusto von Dentz
>>>
>>
>> And what if you'll start downloading email with 10MB attachment?? So
>> it's better to send file descriptor through DBus than lots (and lots)
>> of data. And there is nothing to convert, client will get fd and then
>> just read message from a file - it's simple enough.
>
> Then create a transfer object and notify the agent like we do for
> GetFile, also with this you progress indication like we have with
> normal files and you are also able to catch errors or cancel the
> transfer.
>
> --
> Luiz Augusto von Dentz
>

Generally you may be right, but i'm not sure whether actually tangling
agent (client of the client?) is a good idea -- I'll check it
tomorrow, but AFAIR it's  an additional reversed connection? And
situation with this big message probably is not so often to cause such
a confusion. I would really like to use such API in simplest possible
way, by calling some method and receiving answer and its exactly what
is accomplished with fd.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>
> Generally you may be right, but i'm not sure whether actually tangling
> agent (client of the client?) is a good idea -- I'll check it
> tomorrow, but AFAIR it's  an additional reversed connection? And
> situation with this big message probably is not so often to cause such
> a confusion. I would really like to use such API in simplest possible
> way, by calling some method and receiving answer and its exactly what
> is accomplished with fd.

I haven't seen the implementation but I have a feeling it won't be
that simple, if you use the pipe/unix socket to stream the data them
you end up copying data and the stream still need to be handled  in
client side which will very likely copy/convert the data again. We
have tried such a thing before with A2DP and it was consider
inefficient, so what we do nowadays is passing the bluetooth socket
itself to PulseAudio but note that here it would not be a good idea
since the client would have to deal with OBEX protocol directly.

You could return the transfer object on GetMessage, actually is is
probably a good idea to do this also for GetFile/PutFile, so that the
caller application have direct control on the transfers it has started
and we can probable have a property e.g. Status (Transferring, Error,
Complete) to indicate the transfer status, that would remove the need
to have an agent in the application although the system may still have
one to track the progress and keep history of the transfers.

-- 
Luiz Augusto von Dentz

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Bartosz,
>
> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>
>> Generally you may be right, but i'm not sure whether actually tangling
>> agent (client of the client?) is a good idea -- I'll check it
>> tomorrow, but AFAIR it's  an additional reversed connection? And
>> situation with this big message probably is not so often to cause such
>> a confusion. I would really like to use such API in simplest possible
>> way, by calling some method and receiving answer and its exactly what
>> is accomplished with fd.
>
> I haven't seen the implementation but I have a feeling it won't be
> that simple, if you use the pipe/unix socket to stream the data them
> you end up copying data and the stream still need to be handled  in
> client side which will very likely copy/convert the data again. We
> have tried such a thing before with A2DP and it was consider
> inefficient, so what we do nowadays is passing the bluetooth socket
> itself to PulseAudio but note that here it would not be a good idea
> since the client would have to deal with OBEX protocol directly.
>
> You could return the transfer object on GetMessage, actually is is
> probably a good idea to do this also for GetFile/PutFile, so that the
> caller application have direct control on the transfers it has started
> and we can probable have a property e.g. Status (Transferring, Error,
> Complete) to indicate the transfer status, that would remove the need
> to have an agent in the application although the system may still have
> one to track the progress and keep history of the transfers.
>
> --
> Luiz Augusto von Dentz
>

As far as i can tell adding transfer would be good idea and it's not
necessary to actually track it. But there is still question how to
transfer data? I'm still convinced that passing fd is good idea, maybe
even more flexible would be to pass it from user to obex-client in
DBus call, so user may decide whether it would be more convenience to
use file, pipe or whatever.

So method may look something like this:

string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))

Returning path to the newly created transfer.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Mon, Nov 7, 2011 at 11:46 AM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
> On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
>> Hi Bartosz,
>>
>> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>
>>> Generally you may be right, but i'm not sure whether actually tangling
>>> agent (client of the client?) is a good idea -- I'll check it
>>> tomorrow, but AFAIR it's  an additional reversed connection? And
>>> situation with this big message probably is not so often to cause such
>>> a confusion. I would really like to use such API in simplest possible
>>> way, by calling some method and receiving answer and its exactly what
>>> is accomplished with fd.
>>
>> I haven't seen the implementation but I have a feeling it won't be
>> that simple, if you use the pipe/unix socket to stream the data them
>> you end up copying data and the stream still need to be handled  in
>> client side which will very likely copy/convert the data again. We
>> have tried such a thing before with A2DP and it was consider
>> inefficient, so what we do nowadays is passing the bluetooth socket
>> itself to PulseAudio but note that here it would not be a good idea
>> since the client would have to deal with OBEX protocol directly.
>>
>> You could return the transfer object on GetMessage, actually is is
>> probably a good idea to do this also for GetFile/PutFile, so that the
>> caller application have direct control on the transfers it has started
>> and we can probable have a property e.g. Status (Transferring, Error,
>> Complete) to indicate the transfer status, that would remove the need
>> to have an agent in the application although the system may still have
>> one to track the progress and keep history of the transfers.
>>
>> --
>> Luiz Augusto von Dentz
>>
>
> As far as i can tell adding transfer would be good idea and it's not
> necessary to actually track it. But there is still question how to
> transfer data? I'm still convinced that passing fd is good idea, maybe
> even more flexible would be to pass it from user to obex-client in
> DBus call, so user may decide whether it would be more convenience to
> use file, pipe or whatever.
>
> So method may look something like this:
>
> string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))
>
> Returning path to the newly created transfer.

As I told you passing a fd to pass data is not very efficient because
you are just adding an intermediate buffer since obexd will have to
copy from the socket to the fd where the client read (btw buffering
the whole message in the client is probably a bad idea), in the other
hand the fd could be of a file that would probably work better but it
is no much different than passing a path which was my initial
suggestion and is probably simpler to implement because we have been
doing this already. This way when the transfer is completed it just a
matter of reading the file.

-- 
Luiz Augusto von Dentz

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

On Mon, Nov 7, 2011 at 11:37 AM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Bartosz,
>
> On Mon, Nov 7, 2011 at 11:46 AM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>> On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
>> <luiz.dentz@gmail.com> wrote:
>>> Hi Bartosz,
>>>
>>> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>>
>>>> Generally you may be right, but i'm not sure whether actually tangling
>>>> agent (client of the client?) is a good idea -- I'll check it
>>>> tomorrow, but AFAIR it's  an additional reversed connection? And
>>>> situation with this big message probably is not so often to cause such
>>>> a confusion. I would really like to use such API in simplest possible
>>>> way, by calling some method and receiving answer and its exactly what
>>>> is accomplished with fd.
>>>
>>> I haven't seen the implementation but I have a feeling it won't be
>>> that simple, if you use the pipe/unix socket to stream the data them
>>> you end up copying data and the stream still need to be handled  in
>>> client side which will very likely copy/convert the data again. We
>>> have tried such a thing before with A2DP and it was consider
>>> inefficient, so what we do nowadays is passing the bluetooth socket
>>> itself to PulseAudio but note that here it would not be a good idea
>>> since the client would have to deal with OBEX protocol directly.
>>>
>>> You could return the transfer object on GetMessage, actually is is
>>> probably a good idea to do this also for GetFile/PutFile, so that the
>>> caller application have direct control on the transfers it has started
>>> and we can probable have a property e.g. Status (Transferring, Error,
>>> Complete) to indicate the transfer status, that would remove the need
>>> to have an agent in the application although the system may still have
>>> one to track the progress and keep history of the transfers.
>>>
>>> --
>>> Luiz Augusto von Dentz
>>>
>>
>> As far as i can tell adding transfer would be good idea and it's not
>> necessary to actually track it. But there is still question how to
>> transfer data? I'm still convinced that passing fd is good idea, maybe
>> even more flexible would be to pass it from user to obex-client in
>> DBus call, so user may decide whether it would be more convenience to
>> use file, pipe or whatever.
>>
>> So method may look something like this:
>>
>> string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))
>>
>> Returning path to the newly created transfer.
>
> As I told you passing a fd to pass data is not very efficient because
> you are just adding an intermediate buffer since obexd will have to
> copy from the socket to the fd where the client read (btw buffering
> the whole message in the client is probably a bad idea), in the other
> hand the fd could be of a file that would probably work better but it
> is no much different than passing a path which was my initial
> suggestion and is probably simpler to implement because we have been
> doing this already. This way when the transfer is completed it just a
> matter of reading the file.
>
> --
> Luiz Augusto von Dentz
>

Generally GetMessage (x-bt/message) is set to be buffered in
obc_transfer_get - so there is (AFAICT) no real difference what we
would do with this buffer. And if we would like to modify it to use
file buffering, we can use usr provided fd rather then file name and
let client decide where to store it. In sake of user app simplicity,
as you say earlier.

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Mon, Nov 7, 2011 at 2:42 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
> On Mon, Nov 7, 2011 at 11:37 AM, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
>> Hi Bartosz,
>>
>> On Mon, Nov 7, 2011 at 11:46 AM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>> On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
>>> <luiz.dentz@gmail.com> wrote:
>>>> Hi Bartosz,
>>>>
>>>> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>>>
>>>>> Generally you may be right, but i'm not sure whether actually tangling
>>>>> agent (client of the client?) is a good idea -- I'll check it
>>>>> tomorrow, but AFAIR it's  an additional reversed connection? And
>>>>> situation with this big message probably is not so often to cause such
>>>>> a confusion. I would really like to use such API in simplest possible
>>>>> way, by calling some method and receiving answer and its exactly what
>>>>> is accomplished with fd.
>>>>
>>>> I haven't seen the implementation but I have a feeling it won't be
>>>> that simple, if you use the pipe/unix socket to stream the data them
>>>> you end up copying data and the stream still need to be handled  in
>>>> client side which will very likely copy/convert the data again. We
>>>> have tried such a thing before with A2DP and it was consider
>>>> inefficient, so what we do nowadays is passing the bluetooth socket
>>>> itself to PulseAudio but note that here it would not be a good idea
>>>> since the client would have to deal with OBEX protocol directly.
>>>>
>>>> You could return the transfer object on GetMessage, actually is is
>>>> probably a good idea to do this also for GetFile/PutFile, so that the
>>>> caller application have direct control on the transfers it has started
>>>> and we can probable have a property e.g. Status (Transferring, Error,
>>>> Complete) to indicate the transfer status, that would remove the need
>>>> to have an agent in the application although the system may still have
>>>> one to track the progress and keep history of the transfers.
>>>>
>>>> --
>>>> Luiz Augusto von Dentz
>>>>
>>>
>>> As far as i can tell adding transfer would be good idea and it's not
>>> necessary to actually track it. But there is still question how to
>>> transfer data? I'm still convinced that passing fd is good idea, maybe
>>> even more flexible would be to pass it from user to obex-client in
>>> DBus call, so user may decide whether it would be more convenience to
>>> use file, pipe or whatever.
>>>
>>> So method may look something like this:
>>>
>>> string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))
>>>
>>> Returning path to the newly created transfer.
>>
>> As I told you passing a fd to pass data is not very efficient because
>> you are just adding an intermediate buffer since obexd will have to
>> copy from the socket to the fd where the client read (btw buffering
>> the whole message in the client is probably a bad idea), in the other
>> hand the fd could be of a file that would probably work better but it
>> is no much different than passing a path which was my initial
>> suggestion and is probably simpler to implement because we have been
>> doing this already. This way when the transfer is completed it just a
>> matter of reading the file.
>>
>> --
>> Luiz Augusto von Dentz
>>
>
> Generally GetMessage (x-bt/message) is set to be buffered in
> obc_transfer_get - so there is (AFAICT) no real difference what we
> would do with this buffer. And if we would like to modify it to use
> file buffering, we can use usr provided fd rather then file name and
> let client decide where to store it. In sake of user app simplicity,
> as you say earlier.

That is nothing that couldn't be changed, also whether it is a path or
not the user is still deciding where it should be stored but I guess a
path is actually less troublesome to the client to deal with since not
every binding supports fd passing which can be a problem to end user
application which I suppose this API should be targeting, also using
paths is consistent with other parts of the code GetFile/PutFile.

-- 
Luiz Augusto von Dentz

Re: [RFC] API for MAP client in obex-client

[Bartosz Szatkowski]

On Mon, Nov 7, 2011 at 2:20 PM, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
> Hi Bartosz,
>
> On Mon, Nov 7, 2011 at 2:42 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>> On Mon, Nov 7, 2011 at 11:37 AM, Luiz Augusto von Dentz
>> <luiz.dentz@gmail.com> wrote:
>>> Hi Bartosz,
>>>
>>> On Mon, Nov 7, 2011 at 11:46 AM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>> On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
>>>> <luiz.dentz@gmail.com> wrote:
>>>>> Hi Bartosz,
>>>>>
>>>>> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>>>>
>>>>>> Generally you may be right, but i'm not sure whether actually tangling
>>>>>> agent (client of the client?) is a good idea -- I'll check it
>>>>>> tomorrow, but AFAIR it's  an additional reversed connection? And
>>>>>> situation with this big message probably is not so often to cause such
>>>>>> a confusion. I would really like to use such API in simplest possible
>>>>>> way, by calling some method and receiving answer and its exactly what
>>>>>> is accomplished with fd.
>>>>>
>>>>> I haven't seen the implementation but I have a feeling it won't be
>>>>> that simple, if you use the pipe/unix socket to stream the data them
>>>>> you end up copying data and the stream still need to be handled  in
>>>>> client side which will very likely copy/convert the data again. We
>>>>> have tried such a thing before with A2DP and it was consider
>>>>> inefficient, so what we do nowadays is passing the bluetooth socket
>>>>> itself to PulseAudio but note that here it would not be a good idea
>>>>> since the client would have to deal with OBEX protocol directly.
>>>>>
>>>>> You could return the transfer object on GetMessage, actually is is
>>>>> probably a good idea to do this also for GetFile/PutFile, so that the
>>>>> caller application have direct control on the transfers it has started
>>>>> and we can probable have a property e.g. Status (Transferring, Error,
>>>>> Complete) to indicate the transfer status, that would remove the need
>>>>> to have an agent in the application although the system may still have
>>>>> one to track the progress and keep history of the transfers.
>>>>>
>>>>> --
>>>>> Luiz Augusto von Dentz
>>>>>
>>>>
>>>> As far as i can tell adding transfer would be good idea and it's not
>>>> necessary to actually track it. But there is still question how to
>>>> transfer data? I'm still convinced that passing fd is good idea, maybe
>>>> even more flexible would be to pass it from user to obex-client in
>>>> DBus call, so user may decide whether it would be more convenience to
>>>> use file, pipe or whatever.
>>>>
>>>> So method may look something like this:
>>>>
>>>> string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))
>>>>
>>>> Returning path to the newly created transfer.
>>>
>>> As I told you passing a fd to pass data is not very efficient because
>>> you are just adding an intermediate buffer since obexd will have to
>>> copy from the socket to the fd where the client read (btw buffering
>>> the whole message in the client is probably a bad idea), in the other
>>> hand the fd could be of a file that would probably work better but it
>>> is no much different than passing a path which was my initial
>>> suggestion and is probably simpler to implement because we have been
>>> doing this already. This way when the transfer is completed it just a
>>> matter of reading the file.
>>>
>>> --
>>> Luiz Augusto von Dentz
>>>
>>
>> Generally GetMessage (x-bt/message) is set to be buffered in
>> obc_transfer_get - so there is (AFAICT) no real difference what we
>> would do with this buffer. And if we would like to modify it to use
>> file buffering, we can use usr provided fd rather then file name and
>> let client decide where to store it. In sake of user app simplicity,
>> as you say earlier.
>
> That is nothing that couldn't be changed, also whether it is a path or
> not the user is still deciding where it should be stored but I guess a
> path is actually less troublesome to the client to deal with since not
> every binding supports fd passing which can be a problem to end user
> application which I suppose this API should be targeting, also using
> paths is consistent with other parts of the code GetFile/PutFile.
>
> --
> Luiz Augusto von Dentz
>

OK, so maybe this fd passing would be confusing and may be problematic
if somebody would use java or something.

string GetMessage(string file_name, string handle, dict(uint8 tag,
variant value))

i think that this is as good as we can settle in this discussion, if
there is no serious issues in this model maybe i would start coding
it? (I'll resend full api sometime soon)

-- 
Pozdrowienia - Cheers,
Bartosz Szatkowski

Re: [RFC] API for MAP client in obex-client

[Luiz Augusto von Dentz]

Hi Bartosz,

On Mon, Nov 7, 2011 at 5:10 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
> On Mon, Nov 7, 2011 at 2:20 PM, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
>> Hi Bartosz,
>>
>> On Mon, Nov 7, 2011 at 2:42 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>> On Mon, Nov 7, 2011 at 11:37 AM, Luiz Augusto von Dentz
>>> <luiz.dentz@gmail.com> wrote:
>>>> Hi Bartosz,
>>>>
>>>> On Mon, Nov 7, 2011 at 11:46 AM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>>> On Fri, Nov 4, 2011 at 1:00 PM, Luiz Augusto von Dentz
>>>>> <luiz.dentz@gmail.com> wrote:
>>>>>> Hi Bartosz,
>>>>>>
>>>>>> On Thu, Nov 3, 2011 at 9:01 PM, Bartosz Szatkowski <bulislaw@linux.com> wrote:
>>>>>>>
>>>>>>> Generally you may be right, but i'm not sure whether actually tangling
>>>>>>> agent (client of the client?) is a good idea -- I'll check it
>>>>>>> tomorrow, but AFAIR it's  an additional reversed connection? And
>>>>>>> situation with this big message probably is not so often to cause such
>>>>>>> a confusion. I would really like to use such API in simplest possible
>>>>>>> way, by calling some method and receiving answer and its exactly what
>>>>>>> is accomplished with fd.
>>>>>>
>>>>>> I haven't seen the implementation but I have a feeling it won't be
>>>>>> that simple, if you use the pipe/unix socket to stream the data them
>>>>>> you end up copying data and the stream still need to be handled  in
>>>>>> client side which will very likely copy/convert the data again. We
>>>>>> have tried such a thing before with A2DP and it was consider
>>>>>> inefficient, so what we do nowadays is passing the bluetooth socket
>>>>>> itself to PulseAudio but note that here it would not be a good idea
>>>>>> since the client would have to deal with OBEX protocol directly.
>>>>>>
>>>>>> You could return the transfer object on GetMessage, actually is is
>>>>>> probably a good idea to do this also for GetFile/PutFile, so that the
>>>>>> caller application have direct control on the transfers it has started
>>>>>> and we can probable have a property e.g. Status (Transferring, Error,
>>>>>> Complete) to indicate the transfer status, that would remove the need
>>>>>> to have an agent in the application although the system may still have
>>>>>> one to track the progress and keep history of the transfers.
>>>>>>
>>>>>> --
>>>>>> Luiz Augusto von Dentz
>>>>>>
>>>>>
>>>>> As far as i can tell adding transfer would be good idea and it's not
>>>>> necessary to actually track it. But there is still question how to
>>>>> transfer data? I'm still convinced that passing fd is good idea, maybe
>>>>> even more flexible would be to pass it from user to obex-client in
>>>>> DBus call, so user may decide whether it would be more convenience to
>>>>> use file, pipe or whatever.
>>>>>
>>>>> So method may look something like this:
>>>>>
>>>>> string GetMessage(unix_fd msgfd, string handle, dict(uint8 tag, variant value))
>>>>>
>>>>> Returning path to the newly created transfer.
>>>>
>>>> As I told you passing a fd to pass data is not very efficient because
>>>> you are just adding an intermediate buffer since obexd will have to
>>>> copy from the socket to the fd where the client read (btw buffering
>>>> the whole message in the client is probably a bad idea), in the other
>>>> hand the fd could be of a file that would probably work better but it
>>>> is no much different than passing a path which was my initial
>>>> suggestion and is probably simpler to implement because we have been
>>>> doing this already. This way when the transfer is completed it just a
>>>> matter of reading the file.
>>>>
>>>> --
>>>> Luiz Augusto von Dentz
>>>>
>>>
>>> Generally GetMessage (x-bt/message) is set to be buffered in
>>> obc_transfer_get - so there is (AFAICT) no real difference what we
>>> would do with this buffer. And if we would like to modify it to use
>>> file buffering, we can use usr provided fd rather then file name and
>>> let client decide where to store it. In sake of user app simplicity,
>>> as you say earlier.
>>
>> That is nothing that couldn't be changed, also whether it is a path or
>> not the user is still deciding where it should be stored but I guess a
>> path is actually less troublesome to the client to deal with since not
>> every binding supports fd passing which can be a problem to end user
>> application which I suppose this API should be targeting, also using
>> paths is consistent with other parts of the code GetFile/PutFile.
>>
>> --
>> Luiz Augusto von Dentz
>>
>
> OK, so maybe this fd passing would be confusing and may be problematic
> if somebody would use java or something.
>
> string GetMessage(string file_name, string handle, dict(uint8 tag,
> variant value))
>
> i think that this is as good as we can settle in this discussion, if
> there is no serious issues in this model maybe i would start coding
> it? (I'll resend full api sometime soon)

Sounds good to me.

-- 
Luiz Augusto von Dentz