[FFmpeg-devel] [PATCH] cmdutils: dont call read_header before listing devices

[Lukasz Marek]

On 18.12.2014 01:09, Michael Niedermayer wrote:
> On Wed, Dec 17, 2014 at 10:59:37PM +0100, Lukasz Marek wrote:
>> On 15.12.2014 14:18, Michael Niedermayer wrote:
>>>>   cmdutils.c |    8 ++++++--
>>>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>>> 8d012a5193b0440717f89d920661913ef160e674  0001-cmdutils-dont-call-read_header-before-listing-device.patch
>>>>  From 332bb7456c498518ea72dfdaa0e8c3e76d383f21 Mon Sep 17 00:00:00 2001
>>>> From: Lukasz Marek <lukasz.m.luki2 at gmail.com>
>>>> Date: Mon, 15 Dec 2014 00:31:42 +0100
>>>> Subject: [PATCH] cmdutils: dont call read_header before listing devices
>>>>
>>>> List device callback must be able to return valid list without opening device.
>>>> This callback should return input values for open function, not vice-versa.
>>>> Read header funtion is very likey to fail without proper configuration provided.
>>>
>>> should be ok
>>
>> I changed a patch. I wanted to avoid situation where .read_close is
>> called without .read_header being called before.
>>
>
>>   cmdutils.c |   41 +++++++++++++++++++++++++++++++++++------
>>   1 file changed, 35 insertions(+), 6 deletions(-)
>> 9a93c401d795bae3545a6c6112e71abd98ac22ca  0001-cmdutils-dont-call-read_header-before-listing-device.patch
>>  From 58fe020b8f1c0e809362e152febe3ad715b1c8fc Mon Sep 17 00:00:00 2001
>> From: Lukasz Marek <lukasz.m.luki2 at gmail.com>
>> Date: Mon, 15 Dec 2014 00:31:42 +0100
>> Subject: [PATCH] cmdutils: dont call read_header before listing devices
>>
>> List device callback must be able to return valid list without opening device.
>> This callback should return input values for open function, not vice-versa.
>> Read header funtion is very likey to fail without proper configuration provided.
>>
>> Signed-off-by: Lukasz Marek <lukasz.m.luki2 at gmail.com>
>> ---
>>   cmdutils.c | 41 +++++++++++++++++++++++++++++++++++------
>>   1 file changed, 35 insertions(+), 6 deletions(-)
>>
>> diff --git a/cmdutils.c b/cmdutils.c
>> index 4e0a406..23a5f77 100644
>> --- a/cmdutils.c
>> +++ b/cmdutils.c
>> @@ -2052,7 +2052,37 @@ void *grow_array(void *array, int elem_size, int *size, int new_size)
>>   }
>>
>>   #if CONFIG_AVDEVICE
>> -static int print_device_sources(AVInputFormat *fmt, AVDictionary *opts)
>> +static int alloc_input_context(AVFormatContext **avctx, AVInputFormat *iformat)
>> +{
>> +    AVFormatContext *s = avformat_alloc_context();
>> +    int ret = 0;
>> +
>> +    *avctx = NULL;
>> +    if (!s)
>> +        return AVERROR(ENOMEM);
>> +
>> +    s->iformat = iformat;
>> +    if (s->iformat->priv_data_size > 0) {
>> +        s->priv_data = av_mallocz(s->iformat->priv_data_size);
>> +        if (!s->priv_data) {
>> +            ret = AVERROR(ENOMEM);
>> +            goto error;
>> +        }
>> +        if (s->iformat->priv_class) {
>> +            *(const AVClass**)s->priv_data= s->iformat->priv_class;
>> +            av_opt_set_defaults(s->priv_data);
>> +        }
>> +    } else
>> +        s->priv_data = NULL;
>> +
>> +    *avctx = s;
>> +    return 0;
>> +  error:
>> +    avformat_free_context(s);
>> +    return ret;
>> +}
>> +
>
>> +static int print_device_sources(void *pfmt, AVDictionary *opts)
>>   {
>>       int ret, i;
>>       AVFormatContext *dev = NULL;
>> @@ -2069,13 +2099,12 @@ static int print_device_sources(AVInputFormat *fmt, AVDictionary *opts)
>>           goto fail;
>>       }
>>
>> -    /* TODO: avformat_open_input calls read_header callback which is not necessary.
>> -             Function like avformat_alloc_output_context2 for input could be helpful here. */
>> -    av_dict_copy(&tmp_opts, opts, 0);
>> -    if ((ret = avformat_open_input(&dev, NULL, fmt, &tmp_opts)) < 0) {
>> +    if ((ret = alloc_input_context(&dev, fmt)) < 0) {
>
> this fails building due to lack of a fmt variable

I failed at cherry-pick conflict, thanks.
Updated patch is attached.

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