[FFmpeg-devel] [PATCH] fix MSVC compilation errors

[Mateusz]

W dniu 07.12.2017 o 22:58, Hendrik Leppkes pisze:
> Am 07.12.2017 20:40 schrieb "Mateusz" <mateuszb at poczta.onet.pl>:
> 
> W dniu 07.12.2017 o 10:42, Hendrik Leppkes pisze:
>> On Thu, Dec 7, 2017 at 2:02 AM, Mateusz <mateuszb at poczta.onet.pl> wrote:
>>> After commit 3701d49 'error_resilience: remove avpriv_atomic usage'
>>> we have included windows.h in much more files and we should
>>> avoid conflicts with defines/function declarations.
>>>
>>> We should declare compatible variables for atomic compat wrappers
>>> that expect fixed size variables in atomic_compare_exchange* macro.
>>>
>>> Signed-off-by: Mateusz Brzostek <mateuszb at poczta.onet.pl>
>>> ---
>>>  libavcodec/jpegls.h   |  2 ++
>>>  libavcodec/mjpegdec.h |  2 ++
>>>  libavcodec/mss2.c     |  6 +++---
>>>  libavcodec/utils.c    | 12 ++++++++++++
>>>  libavformat/mxfenc.c  |  2 +-
>>>  5 files changed, 20 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/libavcodec/jpegls.h b/libavcodec/jpegls.h
>>> index c8997c7861..6b89b2afa3 100644
>>> --- a/libavcodec/jpegls.h
>>> +++ b/libavcodec/jpegls.h
>>> @@ -32,6 +32,8 @@
>>>  #include "avcodec.h"
>>>  #include "internal.h"
>>>
>>> +#undef near /* This file uses struct member 'near' which in windows.h
> is defined as empty. */
>>> +
>>>  typedef struct JpeglsContext {
>>>      AVCodecContext *avctx;
>>>  } JpeglsContext;
>>> diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
>>> index c84a40aa6e..c36fba5f22 100644
>>> --- a/libavcodec/mjpegdec.h
>>> +++ b/libavcodec/mjpegdec.h
>>> @@ -39,6 +39,8 @@
>>>  #include "hpeldsp.h"
>>>  #include "idctdsp.h"
>>>
>>> +#undef near /* This file uses struct member 'near' which in windows.h
> is defined as empty. */
>>> +
>>>  #define MAX_COMPONENTS 4
>>>
>>>  typedef struct MJpegDecodeContext {
>>> diff --git a/libavcodec/mss2.c b/libavcodec/mss2.c
>>> index 9e7cc466de..3180af1d60 100644
>>> --- a/libavcodec/mss2.c
>>> +++ b/libavcodec/mss2.c
>>> @@ -464,9 +464,9 @@ static int decode_wmv9(AVCodecContext *avctx, const
> uint8_t *buf, int buf_size,
>>>      return 0;
>>>  }
>>>
>>> -typedef struct Rectangle {
>>> +struct Rectangle {
>>>      int coded, x, y, w, h;
>>> -} Rectangle;
>>> +};
>>>
>>>  #define MAX_WMV9_RECTANGLES 20
>>>  #define ARITH2_PADDING 2
>>> @@ -485,7 +485,7 @@ static int mss2_decode_frame(AVCodecContext *avctx,
> void *data, int *got_frame,
>>>
>>>      int keyframe, has_wmv9, has_mv, is_rle, is_555, ret;
>>>
>>> -    Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
>>> +    struct Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
>>>      int used_rects = 0, i, implicit_rect = 0, av_uninit(wmv9_mask);
>>>
>>>      if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
>>> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
>>> index baf09119fe..70a0764714 100644
>>> --- a/libavcodec/utils.c
>>> +++ b/libavcodec/utils.c
>>> @@ -1943,7 +1943,13 @@ int av_lockmgr_register(int (*cb)(void **mutex,
> enum AVLockOp op))
>>>
>>>  int ff_lock_avcodec(AVCodecContext *log_ctx, const AVCodec *codec)
>>>  {
>>> +#if !defined(COMPAT_ATOMICS_DUMMY_STDATOMIC_H) &&
> !defined(COMPAT_ATOMICS_PTHREAD_STDATOMIC_H) && \
>>> +    !defined(COMPAT_ATOMICS_SUNCC_STDATOMIC_H) &&
> !defined(COMPAT_ATOMICS_WIN32_STDATOMIC_H)
>>>      _Bool exp = 0;
>>> +#else
>>> +    atomic_bool exp = 0;
>>> +#endif
>>> +
>>>      if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE ||
> !codec->init)
>>>          return 0;
>>>
>>> @@ -1969,7 +1975,13 @@ int ff_lock_avcodec(AVCodecContext *log_ctx,
> const AVCodec *codec)
>>>
>>>  int ff_unlock_avcodec(const AVCodec *codec)
>>>  {
>>> +#if !defined(COMPAT_ATOMICS_DUMMY_STDATOMIC_H) &&
> !defined(COMPAT_ATOMICS_PTHREAD_STDATOMIC_H) && \
>>> +    !defined(COMPAT_ATOMICS_SUNCC_STDATOMIC_H) &&
> !defined(COMPAT_ATOMICS_WIN32_STDATOMIC_H)
>>>      _Bool exp = 1;
>>> +#else
>>> +    atomic_bool exp = 1;
>>> +#endif
>>> +
>>>      if (codec->caps_internal & FF_CODEC_CAP_INIT_THREADSAFE ||
> !codec->init)
>>>          return 0;
>>>
>>
>> These ifdefs here are very ugly, and as mentioned in another mail, the
>> atomics in those two functions arent even required - all access to
>> those variables is supposed to be protected by the lockmgr anyway.
>> So it would be easier to just remove any atomic nature of those
>> variables (or at the very lease replace the compare_exchange with a
>> store to solve this problem at hand).
> 
> I'm not sure but are you proposed to revert commit
> https://github.com/FFmpeg/FFmpeg/commit/590136e78da3d091ea99ab5432543d
> 47a559a461
> 
> 
> Basically, yes. Atomics are not needed for this variable, as access to it
> should be serialized anyways.

OK for me. I've sent smaller patch (only near/Rectangle stuff).

Mateusz