for #474, refine the hls publish, donot fetch from source when publish

@@ -1252,7 +1252,7 @@ int SrsHls::initialize(SrsSource* s, ISrsHlsHandler* h)
     return ret;
 }
 
-int SrsHls::on_publish(SrsRequest* req)
+int SrsHls::on_publish(SrsRequest* req, bool fetch_sequence_header)
 {
     int ret = ERROR_SUCCESS;
     
@@ -1282,12 +1282,16 @@ int SrsHls::on_publish(SrsRequest* req)
     // ok, the hls can be dispose, or need to be dispose.
     hls_can_dispose = true;
     
-    // notice the source to get the cached sequence header.
-    // when reload to start hls, hls will never get the sequence header in stream,
-    // use the SrsSource.on_hls_start to push the sequence header to HLS.
-    if ((ret = source->on_hls_start()) != ERROR_SUCCESS) {
-        srs_error("callback source hls start failed. ret=%d", ret);
-        return ret;
+    // when publish, don't need to fetch sequence header, which is old and maybe corrupt.
+    // when reload, we must fetch the sequence header from source cache.
+    if (fetch_sequence_header) {
+        // notice the source to get the cached sequence header.
+        // when reload to start hls, hls will never get the sequence header in stream,
+        // use the SrsSource.on_hls_start to push the sequence header to HLS.
+        if ((ret = source->on_hls_start()) != ERROR_SUCCESS) {
+            srs_error("callback source hls start failed. ret=%d", ret);
+            return ret;
+        }
     }
 
     return ret;

@@ -424,10 +424,11 @@ public:
     */
     virtual int initialize(SrsSource* s, ISrsHlsHandler* h);
     /**
-    * publish stream event, continue to write the m3u8,
-    * for the muxer object not destroyed.
-    */
-    virtual int on_publish(SrsRequest* req);
+     * publish stream event, continue to write the m3u8,
+     * for the muxer object not destroyed.
+     * @param fetch_sequence_header whether fetch sequence from source.
+     */
+    virtual int on_publish(SrsRequest* req, bool fetch_sequence_header);
     /**
     * the unpublish event, only close the muxer, donot destroy the 
     * muxer, for when we continue to publish, the m3u8 will continue.

@@ -1180,7 +1180,7 @@ int SrsSource::on_reload_vhost_hls(string vhost)
     
 #ifdef SRS_AUTO_HLS
     hls->on_unpublish();
-    if ((ret = hls->on_publish(_req)) != ERROR_SUCCESS) {
+    if ((ret = hls->on_publish(_req, true)) != ERROR_SUCCESS) {
         srs_error("hls publish failed. ret=%d", ret);
         return ret;
     }
@@ -2039,7 +2039,7 @@ int SrsSource::on_publish()
     
     // TODO: FIXME: use initialize to set req.
 #ifdef SRS_AUTO_HLS
-    if ((ret = hls->on_publish(_req)) != ERROR_SUCCESS) {
+    if ((ret = hls->on_publish(_req, false)) != ERROR_SUCCESS) {
         srs_error("start hls failed. ret=%d", ret);
         return ret;
     }