On Sat, Dec 3, 2016 at 2:13 PM, Matt Oliver <protogo...@gmail.com> wrote:
> On 3 December 2016 at 23:40, Hendrik Leppkes <h.lepp...@gmail.com> wrote:
>
>> On Sat, Dec 3, 2016 at 1:33 PM, Matt Oliver <protogo...@gmail.com> wrote:
>> >
>> > I havent fully tested Hendriks idea as the msdn docs dont recommend
>> calling
>> > multiple winsock functions at the same time from different threads so i
>> > wasnt sure about how well received a patch that relies on closesocket to
>> > unblock the recv function would be received (although i have seen it
>> > extensively used without issuers). If Hendrik has tested this though with
>> > his local patch without issues then I would accept that as a solution to
>> > fixing my issue. ping Hendrik!
>>
>> I don't really use UDP streaming on a regular basis, but I did test
>> this approach when I build it, and it works just fine.
>> What I did was basically just define pthread_cancel/setcancelstate to
>> empty in udp.c (and define HAVE_PTHREAD_CANCEL in that file to enable
>> the code) and re-shuffle the udp_close code to close the socket to
>> unblock the thread before waiting for it to exit.
>>
>> I don't have a clean and finished patch to go, because I had no real
>> interest in it working on other platforms, so its rather ugly. But the
>> approach is rather simple.
>
>
> Would something like the following work for you:
>
> ---
> libavformat/udp.c | 46 +++++++++++++++++++++++++++++-----------------
> 1 file changed, 29 insertions(+), 17 deletions(-)
>
> diff --git a/libavformat/udp.c b/libavformat/udp.c
> index 3835f98..a30918b 100644
> --- a/libavformat/udp.c
> +++ b/libavformat/udp.c
> @@ -60,14 +60,26 @@
> #define IPPROTO_UDPLITE 136
> #endif
>
> -#if HAVE_PTHREAD_CANCEL
> -#include <pthread.h>
> -#endif
> -
> #ifndef HAVE_PTHREAD_CANCEL
> #define HAVE_PTHREAD_CANCEL 0
> #endif
>
> +#if HAVE_PTHREAD_CANCEL || (HAVE_THREADS && HAVE_WINSOCK2_H)
> +#define THREAD_RXRW 1
> +#else
> +#define THREAD_RXRW 0
> +#endif
> +
> +#if !HAVE_PTHREAD_CANCEL && (HAVE_THREADS && HAVE_WINSOCK2_H)
> +/* Winsock2 recv function can be unblocked by shutting down and closing
> the socket */
> +#define pthread_setcancelstate(x, y)
> +#define pthread_cancel {shutdown(s->udp_fd, SD_BOTH);
> closesocket(s->udp_fd);}
> +#endif
> +
Directly defining pthread_cancel to this seems risky, as someone might
introduce such a call at another place at some point without
realizing.
I would probably feel better to directly see that code where its meant to go.
AFAIK you should only call closesocket without shutdown, though.
> +#if THREAD_RXRW
> +#include "libavutil/thread.h"
> +#endif
> +
> #ifndef IPV6_ADD_MEMBERSHIP
> #define IPV6_ADD_MEMBERSHIP IPV6_JOIN_GROUP
> #define IPV6_DROP_MEMBERSHIP IPV6_LEAVE_GROUP
> @@ -100,7 +112,7 @@ typedef struct UDPContext {
> int64_t bitrate; /* number of bits to send per second */
> int64_t burst_bits;
> int close_req;
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> pthread_t circular_buffer_thread;
> pthread_mutex_t mutex;
> pthread_cond_t cond;
> @@ -495,7 +507,7 @@ static int udp_get_file_handle(URLContext *h)
> return s->udp_fd;
> }
>
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> static void *circular_buffer_task_rx( void *_URLContext)
> {
> URLContext *h = _URLContext;
> @@ -730,7 +742,7 @@ static int udp_open(URLContext *h, const char *uri, int
> flags)
> /* assume if no digits were found it is a request to enable it
> */
> if (buf == endptr)
> s->overrun_nonfatal = 1;
> - if (!HAVE_PTHREAD_CANCEL)
> + if (!THREAD_RXRW)
> av_log(h, AV_LOG_WARNING,
> "'overrun_nonfatal' option was set but it is not
> supported "
> "on this build (pthread support is required)\n");
> @@ -758,14 +770,14 @@ static int udp_open(URLContext *h, const char *uri,
> int flags)
> }
> if (av_find_info_tag(buf, sizeof(buf), "fifo_size", p)) {
> s->circular_buffer_size = strtol(buf, NULL, 10);
> - if (!HAVE_PTHREAD_CANCEL)
> + if (!THREAD_RXRW)
> av_log(h, AV_LOG_WARNING,
> "'circular_buffer_size' option was set but it is
> not supported "
> "on this build (pthread support is required)\n");
> }
> if (av_find_info_tag(buf, sizeof(buf), "bitrate", p)) {
> s->bitrate = strtoll(buf, NULL, 10);
> - if (!HAVE_PTHREAD_CANCEL)
> + if (!THREAD_RXRW)
> av_log(h, AV_LOG_WARNING,
> "'bitrate' option was set but it is not supported "
> "on this build (pthread support is required)\n");
> @@ -951,7 +963,7 @@ static int udp_open(URLContext *h, const char *uri, int
> flags)
>
> s->udp_fd = udp_fd;
>
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> /*
> Create thread in case of:
> 1. Input and circular_buffer_size is set
> @@ -988,7 +1000,7 @@ static int udp_open(URLContext *h, const char *uri,
> int flags)
> #endif
>
> return 0;
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> thread_fail:
> pthread_cond_destroy(&s->cond);
> cond_fail:
> @@ -1019,7 +1031,7 @@ static int udp_read(URLContext *h, uint8_t *buf, int
> size)
> {
> UDPContext *s = h->priv_data;
> int ret;
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> int avail, nonblock = h->flags & AVIO_FLAG_NONBLOCK;
>
> if (s->fifo) {
> @@ -1054,9 +1066,9 @@ static int udp_read(URLContext *h, uint8_t *buf, int
> size)
> int64_t t = av_gettime() + 100000;
> struct timespec tv = { .tv_sec = t / 1000000,
> .tv_nsec = (t % 1000000) * 1000 };
> - if (pthread_cond_timedwait(&s->cond, &s->mutex, &tv) < 0) {
> + if (ret = pthread_cond_timedwait(&s->cond, &s->mutex, &tv)
> < 0) {
> pthread_mutex_unlock(&s->mutex);
> - return AVERROR(errno == ETIMEDOUT ? EAGAIN : errno);
> + return AVERROR(ret == ETIMEDOUT ? EAGAIN : ret);
> }
> nonblock = 1;
> }
> @@ -1079,7 +1091,7 @@ static int udp_write(URLContext *h, const uint8_t
> *buf, int size)
> UDPContext *s = h->priv_data;
> int ret;
>
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> if (s->fifo) {
> uint8_t tmp[4];
>
> @@ -1128,7 +1140,7 @@ static int udp_close(URLContext *h)
> {
> UDPContext *s = h->priv_data;
>
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> // Request close once writing is finished
> if (s->thread_started && !(h->flags & AVIO_FLAG_READ)) {
> pthread_mutex_lock(&s->mutex);
> @@ -1140,7 +1152,7 @@ static int udp_close(URLContext *h)
>
> if (s->is_multicast && (h->flags & AVIO_FLAG_READ))
> udp_leave_multicast_group(s->udp_fd, (struct sockaddr
> *)&s->dest_addr,(struct sockaddr *)&s->local_addr_storage);
> -#if HAVE_PTHREAD_CANCEL
> +#if THREAD_RXRW
> if (s->thread_started) {
> int ret;
> // Cancel only read, as write has been signaled as success to the
> user
> --
>
> Ill split the patch so that pthread_cond_timedwait is separate and name it
> properly if everyone is happy with it first.
In general I agree with Nicolas, split the ifdef renames and the win32
compat into two patches, that way its much clearer whats actually
going on in the patch.
- hendrik
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