From: "Tomas Härdin" <git@haerdin.se>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH v2] avformat/avio: Don't use incompatible function pointer type for call
Date: Mon, 11 Sep 2023 18:53:44 +0200
Message-ID: <acbaa2eceffe75d4cfa00b01031e3ddd5a7b544d.camel@haerdin.se> (raw)
In-Reply-To: <AS8P250MB0744ED41B27FCFD6AF85AFAB8FF3A@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM>
sön 2023-09-10 klockan 12:07 +0200 skrev Andreas Rheinhardt:
> It is undefined behaviour even in cases where it works
> (it works because it is only a const uint8_t* vs. uint8_t*
> difference).
> Instead use a macro to produce two functions with the required
> types to be const-correct and type-safe.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
> ---
> libavformat/avio.c | 98 +++++++++++++++++++++++---------------------
> --
> 1 file changed, 50 insertions(+), 48 deletions(-)
>
> diff --git a/libavformat/avio.c b/libavformat/avio.c
> index ab1c19a58d..9783cb1881 100644
> --- a/libavformat/avio.c
> +++ b/libavformat/avio.c
> @@ -353,63 +353,67 @@ fail:
> return ret;
> }
>
> -static inline int retry_transfer_wrapper(URLContext *h, uint8_t
> *buf,
> - int size, int size_min,
> - int
> (*transfer_func)(URLContext *h,
> -
> uint8_t *buf,
> - int
> size))
> -{
> - int ret, len;
> - int fast_retries = 5;
> - int64_t wait_since = 0;
> -
> - len = 0;
> - while (len < size_min) {
> - if (ff_check_interrupt(&h->interrupt_callback))
> - return AVERROR_EXIT;
> - ret = transfer_func(h, buf + len, size - len);
> - if (ret == AVERROR(EINTR))
> - continue;
> - if (h->flags & AVIO_FLAG_NONBLOCK)
> - return ret;
> - if (ret == AVERROR(EAGAIN)) {
> - ret = 0;
> - if (fast_retries) {
> - fast_retries--;
> - } else {
> - if (h->rw_timeout) {
> - if (!wait_since)
> - wait_since = av_gettime_relative();
> - else if (av_gettime_relative() > wait_since + h-
> >rw_timeout)
> - return AVERROR(EIO);
> - }
> - av_usleep(1000);
> - }
> - } else if (ret == AVERROR_EOF)
> - return (len > 0) ? len : AVERROR_EOF;
> - else if (ret < 0)
> - return ret;
> - if (ret) {
> - fast_retries = FFMAX(fast_retries, 2);
> - wait_since = 0;
> - }
> - len += ret;
> - }
> - return len;
> +#define RETRY_TRANSFER_WRAPPER(RW,
> CONST) \
> +static inline int retry_ ## RW ## _wrapper(URLContext *h, CONST
> uint8_t *buf, \
> + int size, int
> size_min, \
> + int (*RW ##
> _func)(URLContext *h, \
> + CONST
> uint8_t *buf, \
> + int
> size)) \
> +{
> \
> + int ret,
> len; \
> + int fast_retries =
> 5; \
> + int64_t wait_since =
> 0; \
> +
> \
> + len =
> 0; \
> + while (len < size_min)
> { \
> + if (ff_check_interrupt(&h-
> >interrupt_callback)) \
> + return
> AVERROR_EXIT; \
> + ret = RW ## _func(h, buf + len, size -
> len); \
> + if (ret ==
> AVERROR(EINTR)) \
> +
> continue; \
> + if (h->flags &
> AVIO_FLAG_NONBLOCK) \
> + return
> ret; \
> + if (ret == AVERROR(EAGAIN))
> { \
> + ret =
> 0; \
> + if (fast_retries)
> { \
> + fast_retries--
> ; \
> + } else
> { \
> + if (h->rw_timeout)
> { \
> + if
> (!wait_since) \
> + wait_since =
> av_gettime_relative(); \
> + else if (av_gettime_relative() > wait_since + h-
> >rw_timeout) \
> + return
> AVERROR(EIO); \
> +
> } \
> +
> av_usleep(1000); \
> +
> } \
> + } else if (ret ==
> AVERROR_EOF) \
> + return (len > 0) ? len :
> AVERROR_EOF; \
> + else if (ret <
> 0) \
> + return
> ret; \
> + if (ret)
> { \
> + fast_retries = FFMAX(fast_retries,
> 2); \
> + wait_since =
> 0; \
> +
> }
> \
> + len +=
> ret; \
> +
> }
> \
> + return
> len; \
> }
>
> +RETRY_TRANSFER_WRAPPER(read, )
> +RETRY_TRANSFER_WRAPPER(write, const)
> +
> int ffurl_read(URLContext *h, unsigned char *buf, int size)
> {
> if (!(h->flags & AVIO_FLAG_READ))
> return AVERROR(EIO);
> - return retry_transfer_wrapper(h, buf, size, 1, h->prot-
> >url_read);
> + return retry_read_wrapper(h, buf, size, 1, h->prot->url_read);
> }
>
> int ffurl_read_complete(URLContext *h, unsigned char *buf, int size)
> {
> if (!(h->flags & AVIO_FLAG_READ))
> return AVERROR(EIO);
> - return retry_transfer_wrapper(h, buf, size, size, h->prot-
> >url_read);
> + return retry_read_wrapper(h, buf, size, size, h->prot-
> >url_read);
> }
>
> int ffurl_write(URLContext *h, const unsigned char *buf, int size)
> @@ -420,9 +424,7 @@ int ffurl_write(URLContext *h, const unsigned
> char *buf, int size)
> if (h->max_packet_size && size > h->max_packet_size)
> return AVERROR(EIO);
>
> - return retry_transfer_wrapper(h, (unsigned char *)buf, size,
> size,
> - (int (*)(struct URLContext *,
> uint8_t *, int))
> - h->prot->url_write);
> + return retry_write_wrapper(h, buf, size, size, h->prot-
> >url_write);
> }
>
> int64_t ffurl_seek(URLContext *h, int64_t pos, int whence)
Fair enough.
/Tomas
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next prev parent reply other threads:[~2023-09-11 16:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-07 0:23 [FFmpeg-devel] [PATCH 01/21] " Andreas Rheinhardt
2023-09-07 0:32 ` [FFmpeg-devel] [PATCH 02/21] avformat/internal: Avoid casting const away Andreas Rheinhardt
2023-09-09 6:38 ` Tomas Härdin
2023-09-07 0:32 ` [FFmpeg-devel] [PATCH 03/21] avformat/aviobuf: Don't use incompatible function pointer type for call Andreas Rheinhardt
2023-09-09 6:46 ` Tomas Härdin
2023-09-09 9:25 ` Andreas Rheinhardt
2023-09-08 20:38 ` [FFmpeg-devel] [PATCH 01/21] avformat/avio: " Marton Balint
2023-09-09 6:37 ` Tomas Härdin
2023-09-10 8:47 ` Marton Balint
2023-09-10 9:02 ` Andreas Rheinhardt
2023-09-10 18:07 ` Marton Balint
2023-09-10 18:23 ` Andreas Rheinhardt
2023-09-11 17:27 ` [FFmpeg-devel] [PATCH v3] " Andreas Rheinhardt
2023-09-11 18:43 ` Marton Balint
2023-09-12 14:59 ` Andreas Rheinhardt
2023-09-10 10:07 ` [FFmpeg-devel] [PATCH v2] " Andreas Rheinhardt
2023-09-11 16:53 ` Tomas Härdin [this message]
2023-09-09 6:36 ` [FFmpeg-devel] [PATCH 01/21] " Tomas Härdin
2023-09-10 10:18 ` Andreas Rheinhardt
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