commit 51dbe82fedb1af2c74cd1215869bad709d1c0913
author Philipp Hancke <phancke@microsoft.com> Thu Feb 02 12:20:37 2023
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Feb 07 09:45:00 2023
tree 78461f71369e5950fc714a3b1ae1879154401b88
parent e9c3e515c8c456997ec900b1128ccd3f6ce5666f

setOfferedHeaderExtensions: stop any filtered extension

addressing feedback from
  https://github.com/w3c/webrtc-extensions/issues/130
and aligning the behavior with setCodecPreferences.

BUG=chromium:1051821

Change-Id: If0c29e1e16781b6898814e2f888ad08a079fc609
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/286780
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Markus Handell <handellm@webrtc.org>
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#39264}

pc/rtp_transceiver.cc

diff --git a/pc/rtp_transceiver.cc b/pc/rtp_transceiver.cc
index 5f9e876..76549d1 100644
--- a/pc/rtp_transceiver.cc
+++ b/pc/rtp_transceiver.cc
@@ -677,6 +677,15 @@
   return result;
 }
 
+// Helper function to determine mandatory-to-negotiate extensions.
+// See https://www.rfc-editor.org/rfc/rfc8834#name-header-extensions
+// and https://w3c.github.io/webrtc-extensions/#rtcrtptransceiver-interface
+// Since BUNDLE is offered by default, MID is mandatory and can not be turned
+// off via this API.
+bool IsMandatoryHeaderExtension(const std::string& uri) {
+  return uri == RtpExtension::kMidUri;
+}
+
 RTCError RtpTransceiver::SetOfferedRtpHeaderExtensions(
     rtc::ArrayView<const RtpHeaderExtensionCapability>
         header_extensions_to_offer) {
@@ -699,17 +708,20 @@
     }
 
     // Step 2.4-2.5.
-    // - Use of the transceiver interface indicates unified plan is in effect,
-    //   hence the MID extension needs to be enabled.
-    // - Also handle the mandatory video orientation extensions.
-    if ((entry.uri == RtpExtension::kMidUri ||
-         entry.uri == RtpExtension::kVideoRotationUri) &&
+    if (IsMandatoryHeaderExtension(entry.uri) &&
         entry.direction != RtpTransceiverDirection::kSendRecv) {
       return RTCError(RTCErrorType::INVALID_MODIFICATION,
                       "Attempted to stop a mandatory extension.");
     }
   }
 
+  // Set all current extensions but the mandatory ones to stopped.
+  // This means that anything filtered from the input will not show up.
+  for (auto& entry : header_extensions_to_offer_) {
+    if (!IsMandatoryHeaderExtension(entry.uri)) {
+      entry.direction = RtpTransceiverDirection::kStopped;
+    }
+  }
   // Apply mutation after error checking.
   for (const auto& entry : header_extensions_to_offer) {
     auto it = std::find_if(

pc/rtp_transceiver_unittest.cc

diff --git a/pc/rtp_transceiver_unittest.cc b/pc/rtp_transceiver_unittest.cc
index a2f2c36..cdbd551 100644
--- a/pc/rtp_transceiver_unittest.cc
+++ b/pc/rtp_transceiver_unittest.cc
@@ -314,12 +314,6 @@
   EXPECT_THAT(transceiver_->SetOfferedRtpHeaderExtensions(modified_extensions),
               Property(&RTCError::type, RTCErrorType::INVALID_MODIFICATION));
   EXPECT_EQ(transceiver_->HeaderExtensionsToOffer(), extensions_);
-  modified_extensions = extensions_;
-  // Attempting to stop the mandatory video orientation extension.
-  modified_extensions[3].direction = RtpTransceiverDirection::kStopped;
-  EXPECT_THAT(transceiver_->SetOfferedRtpHeaderExtensions(modified_extensions),
-              Property(&RTCError::type, RTCErrorType::INVALID_MODIFICATION));
-  EXPECT_EQ(transceiver_->HeaderExtensionsToOffer(), extensions_);
 }
 
 TEST_F(RtpTransceiverTestForHeaderExtensions,