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

[Michael Niedermayer]

On Thu, Dec 18, 2014 at 01:29:39AM +0100, Lukasz Marek wrote:
> 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.
> 

>  cmdutils.c |   39 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 34 insertions(+), 5 deletions(-)
> 688f0a3fc7e3a81743bc4ce3cc858b880c648595  0001-cmdutils-dont-call-read_header-before-listing-device.patch
> From 2b9a20f97687f11eb5d1fd72db3b25e3f2703b73 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 | 39 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 34 insertions(+), 5 deletions(-)

should be ok, though its a bit complex if user apps need to do this
to get the device list

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

What does censorship reveal? It reveals fear. -- Julian Assange
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