Web MIDI backend for Windows 10

media/midi/midi_manager_winrt.cc

+// Copyright 2016 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 "media/midi/midi_manager_winrt.h"
+
+#include <robuffer.h>
+#include <windows.devices.enumeration.h>
+#include <windows.devices.midi.h>
+#include <wrl/event.h>
+
+#include "base/bind.h"
+#include "base/containers/hash_tables.h"
+#include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/timer/timer.h"
+#include "base/win/windows_version.h"
+
+namespace media {
+namespace midi {
+namespace {
+
+namespace WRL = Microsoft::WRL;
+
+using namespace ABI::Windows::Devices::Enumeration;
+using namespace ABI::Windows::Devices::Midi;
+using namespace ABI::Windows::Foundation;
+using namespace ABI::Windows::Storage::Streams;
+
+// Factory functions that activate and create WinRT components. The caller takes
+// ownership of the returning ComPtr.
+template <typename InterfaceType, base::char16 const* runtime_class_id>
+WRL::ComPtr<InterfaceType> WrlStaticsFactory() {
+  WRL::ComPtr<InterfaceType> com_ptr;
+
+  HRESULT hr = GetActivationFactory(
+      WRL::Wrappers::HStringReference(runtime_class_id).Get(), &com_ptr);
+  DCHECK(SUCCEEDED(hr));
+
+  return com_ptr;
+}
+
+WRL::ComPtr<IBufferFactory> GetBufferFactory() {
+  return WrlStaticsFactory<IBufferFactory,
+                           RuntimeClass_Windows_Storage_Streams_Buffer>();
+}
+
+WRL::ComPtr<IDeviceInformationStatics> GetDeviceInformationStatics() {
+  return WrlStaticsFactory<
+      IDeviceInformationStatics,
+      RuntimeClass_Windows_Devices_Enumeration_DeviceInformation>();
+}
+
+template <typename T, HRESULT (T::*method)(HSTRING*)>
+std::string GetStringFromObjectMethod(T* obj) {
+  HSTRING result;
+  HRESULT hr = (obj->*method)(&result);
+  DCHECK(SUCCEEDED(hr));
+
+  const base::char16* buffer = WindowsGetStringRawBuffer(result, nullptr);
+  if (buffer)
+    return base::WideToUTF8(buffer);
+  return std::string();
+}
+
+template <typename T>
+std::string GetIdString(T* obj) {
+  return GetStringFromObjectMethod<T, &T::get_Id>(obj);
+}
+
+template <typename T>
+std::string GetDeviceIdString(T* obj) {
+  return GetStringFromObjectMethod<T, &T::get_DeviceId>(obj);
+}
+
+std::string GetNameString(IDeviceInformation* info) {
+  return GetStringFromObjectMethod<IDeviceInformation,
+                                   &IDeviceInformation::get_Name>(info);
+}
+
+uint8_t* GetPointerToBufferData(IBuffer* buffer) {
+  WRL::ComPtr<IInspectable> inspectable(
+      reinterpret_cast<IInspectable*>(buffer));
+  WRL::ComPtr<Windows::Storage::Streams::IBufferByteAccess> buffer_byte_access;
+
+  HRESULT hr = inspectable.As(&buffer_byte_access);
+  DCHECK(SUCCEEDED(hr));
+
+  uint8_t* ptr = nullptr;
+  hr = buffer_byte_access->Buffer(&ptr);
+  DCHECK(SUCCEEDED(hr));
+
+  // Lifetime of the pointing buffer is controlled by the buffer object.
+  return ptr;
+}
+
+template <typename InterfaceType>
+struct MidiPort {
+  MidiPort() = default;
+
+  uint32_t index;
+  WRL::ComPtr<InterfaceType> handle;
+  base::TimeTicks start_time;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MidiPort);
+};
+
+template <typename InterfaceType,
+          typename RuntimeType,
+          typename StaticsInterfaceType,
+          base::char16 const* runtime_class_id>
+class MidiPortManager {
+ public:
+  // MidiPortManager instances should be constructed on the COM thread.
+  MidiPortManager(MidiManagerWinrt* midi_manager)
+      : midi_manager_(midi_manager),
+        task_runner_(base::ThreadTaskRunnerHandle::Get()) {}
+
+  void StartWatcher() {

[Shao-Chuan Lee, 2016/08/23 04:33:29]

Missing |thread_checker_| check.

+    HRESULT hr;
+
+    midi_port_statics_ =
+        WrlStaticsFactory<StaticsInterfaceType, runtime_class_id>();
+
+    HSTRING device_selector = nullptr;
+    hr = midi_port_statics_->GetDeviceSelector(&device_selector);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = GetDeviceInformationStatics()->CreateWatcherAqsFilter(device_selector,
+                                                               &watcher_);
+    DCHECK(SUCCEEDED(hr));
+
+    // Register callbacks to WinRT that post state-modifying jobs back to COM
+    // thread. |weak_ptr| and |task_runner| are captured by lambda callbacks for
+    // posting jobs. Note that WinRT callback arguments should not be passed
+    // outside the callback since the pointers may be unavailable afterwards.
+    base::WeakPtr<MidiPortManager> weak_ptr = GetWeakPtrFromFactory();
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner = task_runner_;
+
+    hr = watcher_->add_Added(
+        WRL::Callback<ITypedEventHandler<DeviceWatcher*, DeviceInformation*>>(
+            [weak_ptr, task_runner](IDeviceWatcher* watcher,
+                                    IDeviceInformation* info) {
+              std::string dev_id = GetIdString(info),
+                          dev_name = GetNameString(info);
+
+              task_runner->PostTask(
+                  FROM_HERE, base::Bind(&MidiPortManager::OnAdded, weak_ptr,
+                                        dev_id, dev_name));
+
+              return S_OK;
+            })
+            .Get(),
+        &token_Added_);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = watcher_->add_EnumerationCompleted(
+        WRL::Callback<ITypedEventHandler<DeviceWatcher*, IInspectable*>>(
+            [weak_ptr, task_runner](IDeviceWatcher* watcher,
+                                    IInspectable* insp) {
+              task_runner->PostTask(
+                  FROM_HERE,
+                  base::Bind(&MidiPortManager::OnEnumerationCompleted,
+                             weak_ptr));
+
+              return S_OK;
+            })
+            .Get(),
+        &token_EnumerationCompleted_);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = watcher_->add_Removed(
+        WRL::Callback<
+            ITypedEventHandler<DeviceWatcher*, DeviceInformationUpdate*>>(
+            [weak_ptr, task_runner](IDeviceWatcher* watcher,
+                                    IDeviceInformationUpdate* update) {
+              std::string dev_id = GetIdString(update);
+
+              task_runner->PostTask(
+                  FROM_HERE,
+                  base::Bind(&MidiPortManager::OnRemoved, weak_ptr, dev_id));
+
+              return S_OK;
+            })
+            .Get(),
+        &token_Removed_);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = watcher_->add_Stopped(
+        WRL::Callback<ITypedEventHandler<DeviceWatcher*, IInspectable*>>(
+            [](IDeviceWatcher* watcher, IInspectable* insp) {
+              // Placeholder, does nothing for now.
+              return S_OK;
+            })
+            .Get(),
+        &token_Stopped_);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = watcher_->add_Updated(
+        WRL::Callback<
+            ITypedEventHandler<DeviceWatcher*, DeviceInformationUpdate*>>(
+            [](IDeviceWatcher* watcher, IDeviceInformationUpdate* update) {
+              // TODO(shaochuan): Check for fields to be updated here.
+              return S_OK;
+            })
+            .Get(),
+        &token_Updated_);
+    DCHECK(SUCCEEDED(hr));
+
+    hr = watcher_->Start();
+    DCHECK(SUCCEEDED(hr));
+  }
+
+  ~MidiPortManager() {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    watcher_->remove_Added(token_Added_);
+    watcher_->remove_EnumerationCompleted(token_EnumerationCompleted_);
+    watcher_->remove_Removed(token_Removed_);
+    watcher_->remove_Stopped(token_Stopped_);
+    watcher_->remove_Updated(token_Updated_);
+
+    watcher_->Stop();
+  }
+
+  MidiPort<InterfaceType>* GetPortByDeviceId(std::string dev_id) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    auto it = ports_.find(dev_id);
+    if (it == ports_.end())
+      return nullptr;
+    return it->second.get();
+  }
+
+  MidiPort<InterfaceType>* GetPortByIndex(uint32_t port_index) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    auto it = ports_.find(port_ids_[port_index]);
+    if (it == ports_.end())
+      return nullptr;
+    return it->second.get();
+  }
+
+ protected:
+  // The owning MidiManagerWinrt.
+  MidiManagerWinrt* midi_manager_;
+
+  // Task runner of the COM thread.
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  // Ensures all methods are called on the COM thread.
+  base::ThreadChecker thread_checker_;
+
+ private:
+  // DeviceWatcher callbacks:
+  void OnAdded(std::string dev_id, std::string dev_name) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    // TODO(shaochuan): Disable Microsoft GS Wavetable Synth due to security
+    // reasons. http://crbug.com/499279
+
+    port_names_[dev_id] = dev_name;
+
+    base::string16 dev_id_string16 = base::UTF8ToWide(dev_id);
+    HSTRING dev_id_hstring;
+    HRESULT hr = WindowsCreateString(
+        dev_id_string16.c_str(), static_cast<UINT32>(dev_id_string16.length()),
+        &dev_id_hstring);
+    DCHECK(SUCCEEDED(hr));
+
+    WRL::ComPtr<IAsyncOperation<RuntimeType*>> async_op;
+
+    hr = midi_port_statics_->FromIdAsync(dev_id_hstring, &async_op);
+    DCHECK(SUCCEEDED(hr));
+
+    WindowsDeleteString(dev_id_hstring);
+    dev_id_hstring = nullptr;
+
+    base::WeakPtr<MidiPortManager> weak_ptr = GetWeakPtrFromFactory();
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner = task_runner_;
+
+    hr = async_op->put_Completed(
+        WRL::Callback<IAsyncOperationCompletedHandler<RuntimeType*>>(
+            [weak_ptr, task_runner](IAsyncOperation<RuntimeType*>* async_op,
+                                    AsyncStatus status) {
+              // TODO(shaochuan): Check if port open time is accurate.
+              const auto now = base::TimeTicks::Now();
+
+              InterfaceType* handle;
+              HRESULT hr = async_op->GetResults(&handle);
+              DCHECK(SUCCEEDED(hr));
+
+              // |async_op| is owned by |async_ops_|, safe to pass outside.
+              task_runner->PostTask(
+                  FROM_HERE,
+                  base::Bind(&MidiPortManager::OnCompletedGetPortFromIdAsync,
+                             weak_ptr, handle, now, async_op));
+
+              return S_OK;
+            })
+            .Get());
+    DCHECK(SUCCEEDED(hr));
+
+    // Keep a reference to incompleted |async_op| to ensure lifetime.
+    async_ops_.insert(std::move(async_op));
+  }
+
+  void OnEnumerationCompleted() {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    midi_manager_->OnPortManagerReady();
+  }
+
+  void OnRemoved(std::string dev_id) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    MidiPort<InterfaceType>* port = GetPortByDeviceId(dev_id);
+    DCHECK(port != nullptr);
+
+    SetPortState(port->index, MIDI_PORT_DISCONNECTED);
+
+    port->handle = nullptr;
+  }
+
+  void OnCompletedGetPortFromIdAsync(InterfaceType* handle,
+                                     base::TimeTicks start_time,
+                                     IAsyncOperation<RuntimeType*>* async_op) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    RegisterOnMessageReceived(handle);
+
+    std::string dev_id = GetDeviceIdString(handle);
+
+    MidiPort<InterfaceType>* port = GetPortByDeviceId(dev_id);
+
+    if (port == nullptr) {
+      // TODO(shaochuan): Fill in manufacturer and driver version.
+      AddPort(MidiPortInfo(dev_id, std::string("Manufacturer"),
+                           port_names_[dev_id], std::string("DriverVersion"),
+                           MIDI_PORT_OPENED));
+
+      port = new MidiPort<InterfaceType>;
+      port->index = static_cast<uint32_t>(port_ids_.size());
+
+      ports_[dev_id].reset(port);
+      port_ids_.push_back(dev_id);
+    } else {
+      SetPortState(port->index, MIDI_PORT_CONNECTED);
+    }
+
+    port->handle = handle;
+    port->start_time = start_time;
+
+    // Remove reference to completed |async_op|.
+    auto it = async_ops_.find(async_op);
+    DCHECK(it != async_ops_.end());
+    async_ops_.erase(it);
+  }
+
+  // Overrided by MidiInPortManager to listen to input ports.
+  virtual void RegisterOnMessageReceived(InterfaceType* handle) {}
+
+  // Calls midi_manager_->Add{Input,Output}Port.
+  virtual void AddPort(MidiPortInfo info) = 0;
+
+  // Calls midi_manager_->Set{Input,Output}PortState.
+  virtual void SetPortState(uint32_t port_index, MidiPortState state) = 0;
+
+  // WeakPtrFactory has to be declared in derived class, use this method to
+  // retrieve upcasted WeakPtr for posting tasks.
+  virtual base::WeakPtr<MidiPortManager> GetWeakPtrFromFactory() = 0;
+
+  // Midi{In,Out}PortStatics instance.
+  WRL::ComPtr<StaticsInterfaceType> midi_port_statics_;
+
+  // DeviceWatcher instance and event registration tokens for unsubscribing
+  // events in destructor.
+  WRL::ComPtr<IDeviceWatcher> watcher_;
+  EventRegistrationToken token_Added_, token_EnumerationCompleted_,
+      token_Removed_, token_Stopped_, token_Updated_;
+
+  // All manipulations to these fields should be done on COM thread.
+  base::hash_map<std::string, std::unique_ptr<MidiPort<InterfaceType>>> ports_;
+  std::vector<std::string> port_ids_;
+  base::hash_map<std::string, std::string> port_names_;
+
+  // Keeps AsyncOperation objects before the operation completes.
+  std::set<WRL::ComPtr<IAsyncOperation<RuntimeType*>>> async_ops_;
+};
+
+}  // namespace
+
+class MidiManagerWinrt::MidiInPortManager final
+    : public MidiPortManager<IMidiInPort,
+                             MidiInPort,
+                             IMidiInPortStatics,
+                             RuntimeClass_Windows_Devices_Midi_MidiInPort> {
+ public:
+  MidiInPortManager(MidiManagerWinrt* midi_manager)
+      : MidiPortManager(midi_manager), weak_factory_(this) {}
+
+ private:
+  // MidiPortManager overrides:
+  void RegisterOnMessageReceived(IMidiInPort* handle) override {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    EventRegistrationToken& token = tokens_[GetDeviceIdString(handle)];
+
+    base::WeakPtr<MidiInPortManager> weak_ptr = weak_factory_.GetWeakPtr();
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner = task_runner_;
+
+    handle->add_MessageReceived(
+        WRL::Callback<
+            ITypedEventHandler<MidiInPort*, MidiMessageReceivedEventArgs*>>(
+            [weak_ptr, task_runner](IMidiInPort* handle,
+                                    IMidiMessageReceivedEventArgs* args) {
+              std::string dev_id = GetDeviceIdString(handle);
+
+              WRL::ComPtr<IMidiMessage> message;
+              HRESULT hr = args->get_Message(&message);
+              DCHECK(SUCCEEDED(hr));
+
+              WRL::ComPtr<IBuffer> buffer;
+              hr = message->get_RawData(&buffer);
+              DCHECK(SUCCEEDED(hr));
+
+              uint8_t* p_buffer_data = GetPointerToBufferData(buffer.Get());
+
+              uint32_t data_length;
+              hr = buffer->get_Length(&data_length);
+              DCHECK(SUCCEEDED(hr));
+              DCHECK(data_length != 0);
+
+              std::vector<uint8_t> data(p_buffer_data,
+                                        p_buffer_data + data_length);
+
+              // Time since port opened in 100-nanosecond units.
+              TimeSpan time_span;
+              hr = message->get_Timestamp(&time_span);
+              DCHECK(SUCCEEDED(hr));
+
+              task_runner->PostTask(
+                  FROM_HERE,
+                  base::Bind(&MidiInPortManager::OnMessageReceived, weak_ptr,
+                             dev_id, data, base::TimeDelta::FromMicroseconds(
+                                               time_span.Duration / 10)));
+
+              return S_OK;
+            })
+            .Get(),
+        &token);
+  }
+
+  void AddPort(MidiPortInfo info) final { midi_manager_->AddInputPort(info); }
+
+  void SetPortState(uint32_t port_index, MidiPortState state) final {
+    midi_manager_->SetInputPortState(port_index, state);
+  }
+
+  base::WeakPtr<MidiPortManager> GetWeakPtrFromFactory() final {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    return weak_factory_.GetWeakPtr();
+  }
+
+  // Callback on receiving MIDI input message.
+  void OnMessageReceived(std::string dev_id,
+                         std::vector<uint8_t> data,
+                         base::TimeDelta time_since_start) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    MidiPort<IMidiInPort>* port = GetPortByDeviceId(dev_id);
+    DCHECK(port != nullptr);
+
+    midi_manager_->ReceiveMidiData(port->index, &data[0], data.size(),
+                                   port->start_time + time_since_start);
+  }
+
+  // Event tokens for input message received events.
+  base::hash_map<std::string, EventRegistrationToken> tokens_;
+
+  // Last member to ensure destructed first.
+  base::WeakPtrFactory<MidiInPortManager> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MidiInPortManager);
+};
+
+class MidiManagerWinrt::MidiOutPortManager final
+    : public MidiPortManager<IMidiOutPort,
+                             IMidiOutPort,
+                             IMidiOutPortStatics,
+                             RuntimeClass_Windows_Devices_Midi_MidiOutPort> {
+ public:
+  MidiOutPortManager(MidiManagerWinrt* midi_manager)
+      : MidiPortManager(midi_manager), weak_factory_(this) {}
+
+ private:
+  // MidiPortManager overrides:
+  void AddPort(MidiPortInfo info) final { midi_manager_->AddOutputPort(info); }
+
+  void SetPortState(uint32_t port_index, MidiPortState state) final {
+    midi_manager_->SetOutputPortState(port_index, state);
+  }
+
+  base::WeakPtr<MidiPortManager> GetWeakPtrFromFactory() final {
+    DCHECK(thread_checker_.CalledOnValidThread());
+
+    return weak_factory_.GetWeakPtr();
+  }
+
+  // Last member to ensure destructed first.
+  base::WeakPtrFactory<MidiOutPortManager> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MidiOutPortManager);
+};
+
+MidiManagerWinrt::MidiManagerWinrt() : com_thread_("Windows MIDI COM Thread") {}
+
+MidiManagerWinrt::~MidiManagerWinrt() {}
+
+void MidiManagerWinrt::StartInitialization() {
+  DCHECK(base::win::GetVersion() >= base::win::VERSION_WIN10);
+
+  com_thread_.init_com_with_mta(true);
+  com_thread_.Start();
+
+  com_thread_.task_runner()->PostTask(
+      FROM_HERE, base::Bind(&MidiManagerWinrt::InitializeOnComThread,
+                            base::Unretained(this)));
+}
+
+void MidiManagerWinrt::Finalize() {
+  com_thread_.task_runner()->PostTask(
+      FROM_HERE, base::Bind(&MidiManagerWinrt::FinalizeOnComThread,
+                            base::Unretained(this)));
+
+  // Blocks until FinalizeOnComThread() returns. Delayed MIDI send data tasks
+  // will be ignored.
+  com_thread_.Stop();
+
+  port_manager_ready_count_ = 0;
+}
+
+void MidiManagerWinrt::DispatchSendMidiData(MidiManagerClient* client,
+                                            uint32_t port_index,
+                                            const std::vector<uint8_t>& data,
+                                            double timestamp) {
+  base::AutoLock auto_lock(scheduler_lock_);
+  if (!scheduler_)
+    return;
+
+  scheduler_->PostSendDataTask(
+      client, data.size(), timestamp,
+      base::Bind(&MidiManagerWinrt::SendOnComThread, base::Unretained(this),
+                 port_index, data),
+      com_thread_.task_runner());
+}
+
+void MidiManagerWinrt::InitializeOnComThread() {
+  if (!com_thread_checker_)
+    com_thread_checker_.reset(new base::ThreadChecker);
+  DCHECK(com_thread_checker_->CalledOnValidThread());
+
+  port_manager_in_.reset(new MidiInPortManager(this));
+  port_manager_out_.reset(new MidiOutPortManager(this));
+
+  {
+    base::AutoLock auto_lock(scheduler_lock_);
+    scheduler_.reset(new MidiScheduler(this));
+  }
+
+  port_manager_in_->StartWatcher();
+  port_manager_out_->StartWatcher();
+}
+
+void MidiManagerWinrt::FinalizeOnComThread() {
+  DCHECK(com_thread_checker_->CalledOnValidThread());
+
+  {
+    base::AutoLock auto_lock(scheduler_lock_);
+    scheduler_.reset();
+  }
+
+  port_manager_in_.reset();
+  port_manager_out_.reset();
+}
+
+void MidiManagerWinrt::SendOnComThread(uint32_t port_index,
+                                       const std::vector<uint8_t>& data) {
+  DCHECK(com_thread_checker_->CalledOnValidThread());
+
+  WRL::ComPtr<IBuffer> buffer;
+  HRESULT hr =
+      GetBufferFactory()->Create(static_cast<UINT32>(data.size()), &buffer);
+  DCHECK(SUCCEEDED(hr));
+
+  hr = buffer->put_Length(static_cast<UINT32>(data.size()));
+  DCHECK(SUCCEEDED(hr));
+
+  uint8_t* p_buffer_data = GetPointerToBufferData(buffer.Get());
+
+  std::copy(data.begin(), data.end(), p_buffer_data);
+
+  MidiPort<IMidiOutPort>* port = port_manager_out_->GetPortByIndex(port_index);
+  DCHECK(port != nullptr);
+
+  hr = port->handle->SendBuffer(buffer.Get());
+  DCHECK(SUCCEEDED(hr));
+}
+
+void MidiManagerWinrt::OnPortManagerReady() {
+  DCHECK(com_thread_checker_->CalledOnValidThread());
+  DCHECK(port_manager_ready_count_ < 2);
+
+  if (++port_manager_ready_count_ == 2)
+    CompleteInitialization(Result::OK);
+}
+
+MidiManager* MidiManager::Create() {
+  return new MidiManagerWinrt();
+}
+
+}  // namespace midi
+}  // namespace media