avformat/doc, http, icecast, rtsp: Add option to disable send-expect-100

Fix ticket #7297
The current setting for send-expect-100 option is either
enabled if applicable or forced enabled, no option to force
disable the header. This change is to expand the option setting
to provide more flexibility, which is useful for rstp case.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

doc/protocols.texi

@@ -385,6 +385,11 @@ ffmpeg -i somefile.ogg -chunked_post 0 -c copy -f ogg http://@var{server}:@var{p
 wget --post-file=somefile.ogg http://@var{server}:@var{port}
 @end example
 
+@item send_expect_100
+Send an Expect: 100-continue header for POST. If set to 1 it will send, if set
+to 0 it won't, if set to -1 it will try to send if it is applicable. Default
+value is -1.
+
 @end table
 
 @subsection HTTP Cookies

libavformat/http.c

@@ -113,6 +113,7 @@ typedef struct HTTPContext {
     uint8_t *inflate_buffer;
 #endif /* CONFIG_ZLIB */
     AVDictionary *chained_options;
+    /* -1 = try to send if applicable, 0 = always disabled, 1 = always enabled */
     int send_expect_100;
     char *method;
     int reconnect;
@@ -155,7 +156,7 @@ static const AVOption options[] = {
     { "auth_type", "HTTP authentication type", OFFSET(auth_state.auth_type), AV_OPT_TYPE_INT, { .i64 = HTTP_AUTH_NONE }, HTTP_AUTH_NONE, HTTP_AUTH_BASIC, D | E, "auth_type"},
     { "none", "No auth method set, autodetect", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_NONE }, 0, 0, D | E, "auth_type"},
     { "basic", "HTTP basic authentication", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_BASIC }, 0, 0, D | E, "auth_type"},
-    { "send_expect_100", "Force sending an Expect: 100-continue header for POST", OFFSET(send_expect_100), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
+    { "send_expect_100", "Force sending an Expect: 100-continue header for POST", OFFSET(send_expect_100), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, E },
     { "location", "The actual location of the data received", OFFSET(location), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "offset", "initial byte offset", OFFSET(off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
     { "end_offset", "try to limit the request to bytes preceding this offset", OFFSET(end_off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
@@ -1179,8 +1180,12 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
                                                 local_path, method);
     proxyauthstr = ff_http_auth_create_response(&s->proxy_auth_state, proxyauth,
                                                 local_path, method);
+
      if (post && !s->post_data) {
+        if (s->send_expect_100 != -1) {
             send_expect_100 = s->send_expect_100;
+        } else {
+            send_expect_100 = 0;
             /* The user has supplied authentication but we don't know the auth type,
              * send Expect: 100-continue to get the 401 response including the
              * WWW-Authenticate header, or an 100 continue if no auth actually
@@ -1190,6 +1195,7 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
                 s->http_code != 401)
                 send_expect_100 = 1;
         }
+    }
 
 #if FF_API_HTTP_USER_AGENT
     if (strcmp(s->user_agent_deprecated, DEFAULT_USER_AGENT)) {

libavformat/icecast.c

@@ -115,7 +115,7 @@ static int icecast_open(URLContext *h, const char *uri, int flags)
     av_dict_set(&opt_dict, "auth_type", "basic", 0);
     av_dict_set(&opt_dict, "headers", headers, 0);
     av_dict_set(&opt_dict, "chunked_post", "0", 0);
-    av_dict_set(&opt_dict, "send_expect_100", s->legacy_icecast ? "0" : "1", 0);
+    av_dict_set(&opt_dict, "send_expect_100", s->legacy_icecast ? "-1" : "1", 0);
     if (NOT_EMPTY(s->content_type))
         av_dict_set(&opt_dict, "content_type", s->content_type, 0);
     else

libavformat/rtsp.c

@@ -1797,6 +1797,7 @@ redirect:
                  sessioncookie);
         av_opt_set(rt->rtsp_hd_out->priv_data, "headers", headers, 0);
         av_opt_set(rt->rtsp_hd_out->priv_data, "chunked_post", "0", 0);
+        av_opt_set(rt->rtsp_hd_out->priv_data, "send_expect_100", "0", 0);
 
         /* Initialize the authentication state for the POST session. The HTTP
          * protocol implementation doesn't properly handle multi-pass