tree 4e0aab0053696934c3f9648d8b6ee68085834c7f
parent 5f86c8c3f812d83c8bb3aa8bb4c114033260dadb
author diannahu <diannahu@google.com> 1647529021 -0700
committer Copybara-Service <copybara-worker@google.com> 1647529060 -0700

Avoid invoking ExtensionVisitorInterface::OnSetting() for known SETTINGS parameters.

This CL changes Http2DecoderAdapter::OnSetting() to avoid calling
extension_->OnSetting() for known SETTINGS parameters (defined as
SpdyKnownSettingsId [1]). This change allows classes (e.g., OgHttp2Session) to
implement SpdyFramerVisitorInterface and ExtensionVisitorInterface without
having known SETTINGS parameters passed to them twice.

Archaeology shows prior state as:
  1. SpdyFramerVisitorInterface::OnSetting() only accepted known SETTINGS;
     ExtensionVisitorInterface::OnSetting() only accepted unknown SETTINGS.
  2. Both OnSetting()s accepted known and unknown SETTINGS as of cl/186393706.
  3. This CL causes ExtensionVisitorInterface::OnSetting() to only accept
     unknown SETTINGS; SpdyFramerVisitorInterface::OnSetting() still accepts
     known and unknown SETTINGS.

Note that Http2SettingsFields has a method IsSupportedParameter() [2], but that
would return false for certain SETTINGS parameters like
SETTINGS_ENABLE_CONNECT_PROTOCOL that we do not want to send to the
ExtensionVisitorInterface. Thus, this CL opts for ParseSettingsId() instead and
adds coverage to SpdyFramerTest.ReadKnownAndUnknownSettingsWithExtension.

This CL should be a functional no-op because production
ExtensionVisitorInterface::OnSetting() implementations currently check only for
the METADATA SETTINGS parameter, which would still be considered unknown.

[1] http://google3/third_party/spdy/core/spdy_protocol.h;l=139-162;rcl=387836338
[2] http://google3/third_party/http2/http2_structures.h;l=214;rcl=434624268

PiperOrigin-RevId: 435345949