avformat/http: Add option to limit total reconnect delay

The existing option only allows users to set the max delay for a
single attempt, rather than the total allowed delay, which is both
pretty unintitive, and only applicable when exponential backoff is
used.

The default for this option is set to 256, which is just above the
effective total delay accomplished by the the existing
reconnect_delay_max default of 120.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavformat/http.c

@@ -139,6 +139,7 @@ typedef struct HTTPContext {
     AVDictionary *redirect_cache;
     uint64_t filesize_from_content_range;
     int reconnect_max_retries;
+    int reconnect_delay_total_max;
 } HTTPContext;
 
 #define OFFSET(x) offsetof(HTTPContext, x)
@@ -178,6 +179,7 @@ static const AVOption options[] = {
     { "reconnect_streamed", "auto reconnect streamed / non seekable streams", OFFSET(reconnect_streamed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
     { "reconnect_delay_max", "max reconnect delay in seconds after which to give up", OFFSET(reconnect_delay_max), AV_OPT_TYPE_INT, { .i64 = 120 }, 0, UINT_MAX/1000/1000, D },
     { "reconnect_max_retries", "the max number of times to retry a connection", OFFSET(reconnect_max_retries), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, D },
+    { "reconnect_delay_total_max", "max total reconnect delay in seconds after which to give up", OFFSET(reconnect_delay_total_max), AV_OPT_TYPE_INT, { .i64 = 256 }, 0, UINT_MAX/1000/1000, D },
     { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
     { "resource", "The resource requested by a client", OFFSET(resource), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { "reply_code", "The http status code to return to a client", OFFSET(reply_code), AV_OPT_TYPE_INT, { .i64 = 200}, INT_MIN, 599, E},
@@ -360,6 +362,7 @@ static int http_open_cnx(URLContext *h, AVDictionary **options)
     HTTPContext *s = h->priv_data;
     int ret, conn_attempts = 1, auth_attempts = 0, redirects = 0;
     int reconnect_delay = 0;
+    int reconnect_delay_total = 0;
     uint64_t off;
     char *cached;
 
@@ -386,13 +389,15 @@ redo:
     if (ret < 0) {
         if (!http_should_reconnect(s, ret) ||
             reconnect_delay > s->reconnect_delay_max ||
-            (s->reconnect_max_retries >= 0 && conn_attempts > s->reconnect_max_retries))
+            (s->reconnect_max_retries >= 0 && conn_attempts > s->reconnect_max_retries) ||
+            reconnect_delay_total > s->reconnect_delay_total_max)
             goto fail;
 
         av_log(h, AV_LOG_WARNING, "Will reconnect at %"PRIu64" in %d second(s).\n", off, reconnect_delay);
         ret = ff_network_sleep_interruptible(1000U * 1000 * reconnect_delay, &h->interrupt_callback);
         if (ret != AVERROR(ETIMEDOUT))
             goto fail;
+        reconnect_delay_total += reconnect_delay;
         reconnect_delay = 1 + 2 * reconnect_delay;
         conn_attempts++;
 
@@ -1699,6 +1704,7 @@ static int http_read_stream(URLContext *h, uint8_t *buf, int size)
     int err, read_ret;
     int64_t seek_ret;
     int reconnect_delay = 0;
+    int reconnect_delay_total = 0;
     int conn_attempts = 1;
 
     if (!s->hd)
@@ -1728,13 +1734,15 @@ static int http_read_stream(URLContext *h, uint8_t *buf, int size)
             !(s->reconnect_at_eof && read_ret == AVERROR_EOF))
             break;
 
-        if (reconnect_delay > s->reconnect_delay_max || (s->reconnect_max_retries >= 0 && conn_attempts > s->reconnect_max_retries))
+        if (reconnect_delay > s->reconnect_delay_max || (s->reconnect_max_retries >= 0 && conn_attempts > s->reconnect_max_retries) ||
+            reconnect_delay_total > s->reconnect_delay_total_max)
             return AVERROR(EIO);
 
         av_log(h, AV_LOG_WARNING, "Will reconnect at %"PRIu64" in %d second(s), error=%s.\n", s->off, reconnect_delay, av_err2str(read_ret));
         err = ff_network_sleep_interruptible(1000U*1000*reconnect_delay, &h->interrupt_callback);
         if (err != AVERROR(ETIMEDOUT))
             return err;
+        reconnect_delay_total += reconnect_delay;
         reconnect_delay = 1 + 2*reconnect_delay;
         conn_attempts++;
         seek_ret = http_seek_internal(h, target, SEEK_SET, 1);

libavformat/version.h

@@ -32,7 +32,7 @@
 #include "version_major.h"
 
 #define LIBAVFORMAT_VERSION_MINOR   3
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MICRO 102
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \