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

[Hendrik Leppkes]

On Fri, Dec 8, 2017 at 8:49 AM, Mateusz <mateuszb at poczta.onet.pl> wrote:
> 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).
>

LGTM.