conference/auto-answer: fix request media change

In conference and auto-answer mode, if the remote peer requests
a media change, the remote media was used to configure the local
media. This is bad, since if the remote muted its audio, it will
also mute the local audio.
Now, the existing media will not be modified, and the new media
will be automatically added if any.

Gitlab: #688

Change-Id: Id5388ed916eaa5755202b4b5b5fad118f0dc9c1e

src/conference.cpp

@@ -549,12 +549,25 @@ Conference::handleMediaChangeRequest(const std::shared_ptr<Call>& call,
     auto updateMixer = call->checkMediaChangeRequest(remoteMediaList);
 
     // NOTE:
-    // Since this is a conference, accept any media change request.
+    // Since this is a conference, newly added media will be also
+    // accepted.
     // This also means that if original call was an audio-only call,
     // the local camera will be enabled, unless the video is disabled
     // in the account settings.
 
-    call->answerMediaChangeRequest(remoteMediaList);
+    std::vector<DRing::MediaMap> newMediaList;
+    newMediaList.reserve(remoteMediaList.size());
+    for (auto const& media : call->getMediaAttributeList()) {
+        newMediaList.emplace_back(MediaAttribute::toMediaMap(media));
+    }
+
+    if (remoteMediaList.size() > newMediaList.size()) {
+        for (auto idx = newMediaList.size(); idx < remoteMediaList.size(); idx++) {
+            newMediaList.emplace_back(remoteMediaList[idx]);
+        }
+    }
+
+    call->answerMediaChangeRequest(newMediaList);
     call->enterConference(shared_from_this());
 
     if (updateMixer and getState() == Conference::State::ACTIVE_ATTACHED) {

src/sip/sipcall.cpp

@@ -2497,15 +2497,15 @@ SIPCall::checkMediaChangeRequest(const std::vector<DRing::MediaMap>& remoteMedia
 
     JAMI_DBG("[call:%s] Received a media change request", getCallId().c_str());
 
-    auto remoteMediaAtrrList = MediaAttribute::buildMediaAttributesList(remoteMediaList,
+    auto remoteMediaAttrList = MediaAttribute::buildMediaAttributesList(remoteMediaList,
                                                                         isSrtpEnabled());
-    if (remoteMediaAtrrList.size() != rtpStreams_.size())
+    if (remoteMediaAttrList.size() != rtpStreams_.size())
         return true;
 
     for (size_t i = 0; i < rtpStreams_.size(); i++) {
-        if (remoteMediaAtrrList[i].type_ != rtpStreams_[i].mediaAttribute_->type_)
+        if (remoteMediaAttrList[i].type_ != rtpStreams_[i].mediaAttribute_->type_)
             return true;
-        if (remoteMediaAtrrList[i].enabled_ != rtpStreams_[i].mediaAttribute_->enabled_)
+        if (remoteMediaAttrList[i].enabled_ != rtpStreams_[i].mediaAttribute_->enabled_)
             return true;
     }
 
@@ -2533,12 +2533,25 @@ SIPCall::handleMediaChangeRequest(const std::vector<DRing::MediaMap>& remoteMedi
 
     if (account->isAutoAnswerEnabled()) {
         // NOTE:
-        // Since the auto-answer is enabled in the account, media change requests
-        // are automatically accepted too. This also means that if the original
-        // call was an audio-only call, and the remote added the video, the local
-        // camera will be enabled, unless the video is disabled in the account
-        // settings.
-        answerMediaChangeRequest(remoteMediaList);
+        // Since the auto-answer is enabled in the account, newly
+        // added media are accepted too.
+        // This also means that if original call was an audio-only call,
+        // the local camera will be enabled, unless the video is disabled
+        // in the account settings.
+
+        std::vector<DRing::MediaMap> newMediaList;
+        newMediaList.reserve(remoteMediaList.size());
+        for (auto const& stream : rtpStreams_) {
+            newMediaList.emplace_back(MediaAttribute::toMediaMap(*stream.mediaAttribute_));
+        }
+
+        assert(remoteMediaList.size() > 0);
+        if (remoteMediaList.size() > newMediaList.size()) {
+            for (auto idx = newMediaList.size(); idx < remoteMediaList.size(); idx++) {
+                newMediaList.emplace_back(remoteMediaList[idx]);
+            }
+        }
+        answerMediaChangeRequest(newMediaList);
         return;
     }