chromium/src/third_party/blink/renderer/modules/mediastream/user_media_client.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/modules/mediastream/user_media_client.h"

#include <stddef.h>
#include <algorithm>
#include <utility>

#include "base/location.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/stringprintf.h"
#include "third_party/blink/public/common/browser_interface_broker_proxy.h"
#include "third_party/blink/public/platform/modules/webrtc/webrtc_logging.h"
#include "third_party/blink/public/web/modules/mediastream/web_media_stream_device_observer.h"
#include "third_party/blink/public/web/web_local_frame.h"
#include "third_party/blink/renderer/core/frame/local_dom_window.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/modules/mediastream/apply_constraints_processor.h"
#include "third_party/blink/renderer/modules/peerconnection/peer_connection_tracker.h"
#include "third_party/blink/renderer/platform/mediastream/media_constraints.h"
#include "third_party/blink/renderer/platform/mediastream/webrtc_uma_histograms.h"
#include "third_party/blink/renderer/platform/wtf/functional.h"

namespace blink {
namespace {

static int g_next_request_id = 0;

// The histogram counts the number of calls to the JS API
// getUserMedia(), getDisplayMedia() or GetCurrentBrowsingContextMedia().
void UpdateAPICount(UserMediaRequest::MediaType media_type) {
  RTCAPIName api_name = RTCAPIName::kGetUserMedia;
  switch (media_type) {
    case UserMediaRequest::MediaType::kUserMedia:
      api_name = RTCAPIName::kGetUserMedia;
      break;
    case UserMediaRequest::MediaType::kDisplayMedia:
      api_name = RTCAPIName::kGetDisplayMedia;
      break;
    case UserMediaRequest::MediaType::kGetCurrentBrowsingContextMedia:
      api_name = RTCAPIName::kGetCurrentBrowsingContextMedia;
      break;
  }
  UpdateWebRTCMethodCount(api_name);
}

}  // namespace

UserMediaClient::Request::Request(UserMediaRequest* user_media_request)
    : user_media_request_(user_media_request) {
  DCHECK(user_media_request_);
  DCHECK(!apply_constraints_request_);
  DCHECK(!track_to_stop_);
}

UserMediaClient::Request::Request(blink::ApplyConstraintsRequest* request)
    : apply_constraints_request_(request) {
  DCHECK(apply_constraints_request_);
  DCHECK(!user_media_request_);
  DCHECK(!track_to_stop_);
}

UserMediaClient::Request::Request(MediaStreamComponent* track_to_stop)
    : track_to_stop_(track_to_stop) {
  DCHECK(track_to_stop_);
  DCHECK(!user_media_request_);
  DCHECK(!apply_constraints_request_);
}

UserMediaClient::Request::~Request() = default;

UserMediaRequest* UserMediaClient::Request::MoveUserMediaRequest() {
  auto user_media_request = user_media_request_;
  user_media_request_ = nullptr;
  return user_media_request;
}

UserMediaClient::UserMediaClient(
    LocalFrame* frame,
    UserMediaProcessor* user_media_processor,
    scoped_refptr<base::SingleThreadTaskRunner> task_runner)
    : frame_(frame),
      user_media_processor_(user_media_processor),
      apply_constraints_processor_(
          MakeGarbageCollected<ApplyConstraintsProcessor>(
              WTF::BindRepeating(
                  [](UserMediaClient* client)
                      -> mojom::blink::MediaDevicesDispatcherHost* {
                    // |client| is guaranteed to be not null because |client|
                    // owns this ApplyConstraintsProcessor.
                    DCHECK(client);
                    return client->GetMediaDevicesDispatcher();
                  },
                  WrapWeakPersistent(this)),
              std::move(task_runner))),
      media_devices_dispatcher_(frame->DomWindow()) {
  if (frame_) {
    // WrapWeakPersistent is safe because the |frame_| owns UserMediaClient.
    frame_->SetIsCapturingMediaCallback(WTF::BindRepeating(
        [](UserMediaClient* client) { return client && client->IsCapturing(); },
        WrapWeakPersistent(this)));
  }
}

UserMediaClient::UserMediaClient(
    LocalFrame* frame,
    scoped_refptr<base::SingleThreadTaskRunner> task_runner)
    : UserMediaClient(
          frame,
          MakeGarbageCollected<UserMediaProcessor>(
              frame,
              WTF::BindRepeating(
                  [](UserMediaClient* client)
                      -> mojom::blink::MediaDevicesDispatcherHost* {
                    // |client| is guaranteed to be not null because |client|
                    // owns this UserMediaProcessor.
                    DCHECK(client);
                    return client->GetMediaDevicesDispatcher();
                  },
                  WrapWeakPersistent(this)),
              frame->GetTaskRunner(blink::TaskType::kInternalMedia)),
          std::move(task_runner)) {}

UserMediaClient::~UserMediaClient() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

  // Ensure that ContextDestroyed() gets called before the destructor.
  DCHECK(!is_processing_request_);
}

void UserMediaClient::RequestUserMedia(UserMediaRequest* user_media_request) {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  DCHECK(user_media_request);
  DCHECK(user_media_request->Audio() || user_media_request->Video());
  // GetWindow() may be null if we are in a test.
  // In that case, it's OK to not check frame().

  DCHECK(!user_media_request->GetWindow() ||
         frame_ == user_media_request->GetWindow()->GetFrame());

  // Save histogram data so we can see how much GetUserMedia is used.
  UpdateAPICount(user_media_request->MediaRequestType());

  // TODO(crbug.com/787254): Communicate directly with the
  // PeerConnectionTrackerHost mojo object once it is available from Blink.
  PeerConnectionTracker::GetInstance()->TrackGetUserMedia(user_media_request);

  int request_id = g_next_request_id++;
  blink::WebRtcLogMessage(base::StringPrintf(
      "UMCI::RequestUserMedia({request_id=%d}, {audio constraints=%s}, "
      "{video constraints=%s})",
      request_id,
      user_media_request->AudioConstraints().ToString().Utf8().c_str(),
      user_media_request->VideoConstraints().ToString().Utf8().c_str()));

  // The value returned by HasTransientUserActivation() is used by the browser
  // to make decisions about the permissions UI. Its value can be lost while
  // switching threads, so saving its value here.
  //
  // TODO(mustaq): The description above seems specific to pre-UAv2 stack-based
  // tokens.  Perhaps we don't need to preserve this bit?
  bool has_transient_user_activation = false;
  if (LocalDOMWindow* window = user_media_request->GetWindow()) {
    has_transient_user_activation =
        LocalFrame::HasTransientUserActivation(window->GetFrame());
  }
  user_media_request->set_request_id(request_id);
  user_media_request->set_has_transient_user_activation(
      has_transient_user_activation);
  pending_request_infos_.push_back(
      MakeGarbageCollected<Request>(user_media_request));
  if (!is_processing_request_)
    MaybeProcessNextRequestInfo();
}

void UserMediaClient::ApplyConstraints(
    blink::ApplyConstraintsRequest* user_media_request) {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);

  pending_request_infos_.push_back(
      MakeGarbageCollected<Request>(user_media_request));
  if (!is_processing_request_)
    MaybeProcessNextRequestInfo();
}

void UserMediaClient::StopTrack(MediaStreamComponent* track) {
  pending_request_infos_.push_back(MakeGarbageCollected<Request>(track));
  if (!is_processing_request_)
    MaybeProcessNextRequestInfo();
}

bool UserMediaClient::IsCapturing() {
  return user_media_processor_->HasActiveSources();
}

void UserMediaClient::MaybeProcessNextRequestInfo() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  if (is_processing_request_ || pending_request_infos_.empty())
    return;

  auto current_request = std::move(pending_request_infos_.front());
  pending_request_infos_.pop_front();
  is_processing_request_ = true;

  if (current_request->IsUserMedia()) {
    user_media_processor_->ProcessRequest(
        current_request->MoveUserMediaRequest(),
        WTF::Bind(&UserMediaClient::CurrentRequestCompleted,
                  WrapWeakPersistent(this)));
  } else if (current_request->IsApplyConstraints()) {
    apply_constraints_processor_->ProcessRequest(
        current_request->apply_constraints_request(),
        WTF::Bind(&UserMediaClient::CurrentRequestCompleted,
                  WrapWeakPersistent(this)));
  } else {
    DCHECK(current_request->IsStopTrack());
    MediaStreamTrackPlatform* track = MediaStreamTrackPlatform::GetTrack(
        WebMediaStreamTrack(current_request->track_to_stop()));
    if (track) {
      track->StopAndNotify(WTF::Bind(&UserMediaClient::CurrentRequestCompleted,
                                     WrapWeakPersistent(this)));
    } else {
      CurrentRequestCompleted();
    }
  }
}

void UserMediaClient::CurrentRequestCompleted() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  is_processing_request_ = false;
  if (!pending_request_infos_.empty()) {
    frame_->GetTaskRunner(blink::TaskType::kInternalMedia)
        ->PostTask(FROM_HERE,
                   WTF::Bind(&UserMediaClient::MaybeProcessNextRequestInfo,
                             WrapWeakPersistent(this)));
  }
}

void UserMediaClient::CancelUserMediaRequest(
    UserMediaRequest* user_media_request) {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  {
    // TODO(guidou): Remove this conditional logging. https://crbug.com/764293
    UserMediaRequest* request = user_media_processor_->CurrentRequest();
    if (request == user_media_request) {
      blink::WebRtcLogMessage(
          base::StringPrintf("UMCI::CancelUserMediaRequest. request_id=%d",
                             request->request_id()));
    }
  }

  bool did_remove_request = false;
  if (user_media_processor_->DeleteUserMediaRequest(user_media_request)) {
    did_remove_request = true;
  } else {
    for (auto it = pending_request_infos_.begin();
         it != pending_request_infos_.end(); ++it) {
      if ((*it)->IsUserMedia() &&
          (*it)->user_media_request() == user_media_request) {
        pending_request_infos_.erase(it);
        did_remove_request = true;
        break;
      }
    }
  }

  if (did_remove_request) {
    // We can't abort the stream generation process.
    // Instead, erase the request. Once the stream is generated we will stop the
    // stream if the request does not exist.
    LogUserMediaRequestWithNoResult(
        blink::MEDIA_STREAM_REQUEST_EXPLICITLY_CANCELLED);
  }
}

void UserMediaClient::DeleteAllUserMediaRequests() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  if (frame_)
    frame_->SetIsCapturingMediaCallback(LocalFrame::IsCapturingMediaCallback());
  user_media_processor_->StopAllProcessing();
  is_processing_request_ = false;
  pending_request_infos_.clear();
}

void UserMediaClient::ContextDestroyed() {
  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
  // Cancel all outstanding UserMediaRequests.
  DeleteAllUserMediaRequests();
}

void UserMediaClient::Trace(Visitor* visitor) const {
  visitor->Trace(frame_);
  visitor->Trace(user_media_processor_);
  visitor->Trace(apply_constraints_processor_);
  visitor->Trace(media_devices_dispatcher_);
  visitor->Trace(pending_request_infos_);
}

void UserMediaClient::SetMediaDevicesDispatcherForTesting(
    mojo::PendingRemote<blink::mojom::blink::MediaDevicesDispatcherHost>
        media_devices_dispatcher) {
  media_devices_dispatcher_.Bind(
      std::move(media_devices_dispatcher),
      frame_->GetTaskRunner(blink::TaskType::kInternalMedia));
}

blink::mojom::blink::MediaDevicesDispatcherHost*
UserMediaClient::GetMediaDevicesDispatcher() {
  if (!media_devices_dispatcher_.is_bound()) {
    frame_->GetBrowserInterfaceBroker().GetInterface(
        media_devices_dispatcher_.BindNewPipeAndPassReceiver(
            frame_->GetTaskRunner(blink::TaskType::kInternalMedia)));
  }

  return media_devices_dispatcher_.get();
}

}  // namespace blink