Web MIDI: adding backend to support dynamic instantiation on Windows

media/midi/dynamically_initialized_midi_manager_win.cc

+// Copyright 2017 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/dynamically_initialized_midi_manager_win.h"
+
+#include <windows.h>
+
+#include <mmreg.h>
+#include <mmsystem.h>
+
+#include <algorithm>
+#include <string>
+
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/synchronization/lock.h"
+#include "media/midi/midi_port_info.h"
+#include "media/midi/midi_service.h"
+
+namespace midi {
+
+namespace {
+
+// Global variables to identify MidiManager instance.
+constexpr int kInvalidInstanceId = -1;
+int g_active_instance_id = kInvalidInstanceId;
+DynamicallyInitializedMidiManagerWin* g_manager_instance = nullptr;
+
+// Obtains base::Lock instance pointer to lock instance_id.
+base::Lock* GetInstanceIdLock() {
+  static base::Lock* lock = new base::Lock;
+  return lock;
+}
+
+// Issues unique MidiManager instance ID.
+int IssueNextInstanceId() {
+  static int id = kInvalidInstanceId;
+  return ++id;
+}
+
+// Use single TaskRunner for all tasks running outside the I/O thread.
+constexpr int kTaskRunner = 0;
+
+// Obtains base::Lock instance pointer to ensure tasks run safely on TaskRunner.
+base::Lock* GetTaskLock() {
+  static base::Lock* lock = new base::Lock;
+  return lock;
+}
+
+// Helper function to run a posted task on TaskRunner safely.
+void RunTask(int instance_id, const base::Closure& task) {
+  // Obtains task lock to ensure that the instance should not complete
+  // Finalize() while running the |task|.
+  base::AutoLock task_lock(*GetTaskLock());
+  {
+    // If Finalize() finished before the lock avobe, do nothing.
+    base::AutoLock lock(*GetInstanceIdLock());
+    if (instance_id != g_active_instance_id)
+      return;
+  }
+  task.Run();
+}
+
+// TODO(toyoshim): Factor out TaskRunner related functionaliries above, and
+// deprecate MidiScheduler. It should be available via MidiManager::scheduler().
+
+class Port {
+ public:
+  Port(const std::string& type,
+       uint32_t device_id,
+       uint16_t manufacturer_id,
+       uint16_t product_id,
+       uint32_t driver_version,
+       const std::string& product_name)
+      : index_(0u),
+        type_(type),
+        device_id_(device_id),
+        manufacturer_id_(manufacturer_id),
+        product_id_(product_id),
+        driver_version_(driver_version),
+        product_name_(product_name) {
+    info_.manufacturer = "unknown";  // TODO(toyoshim): Use USB information.
+    info_.name = product_name_;
+    info_.version = base::StringPrintf("%d.%d", HIBYTE(driver_version_),
+                                       LOBYTE(driver_version_));
+    info_.state = mojom::PortState::DISCONNECTED;
+  }
+
+  virtual ~Port() {}
+
+  bool operator==(const Port& other) const {
+    // Should not use |device_id| for comparison because it can be changed on
+    // each enumeration.
+    // Since the GUID will be changed on each enumeration for Microsoft GS
+    // Wavetable synth and might be done for others, do not use it for device
+    // comparison.
+    return manufacturer_id_ == other.manufacturer_id_ &&
+           product_id_ == other.product_id_ &&
+           driver_version_ == other.driver_version_ &&
+           product_name_ == other.product_name_;
+  }
+
+  bool IsConnected() const {
+    return info_.state != mojom::PortState::DISCONNECTED;
+  }
+
+  void set_index(size_t index) {
+    index_ = index;
+    // TODO(toyoshim): Use hashed ID.
+    info_.id = base::StringPrintf("%s-%d", type_.c_str(), index_);
+  }
+  size_t index() { return index_; }
+  void set_device_id(uint32_t device_id) { device_id_ = device_id; }
+  uint32_t device_id() { return device_id_; }
+  const MidiPortInfo& info() { return info_; }
+
+  virtual bool Connect() {
+    if (info_.state != mojom::PortState::DISCONNECTED)
+      return false;
+
+    info_.state = mojom::PortState::CONNECTED;
+    // TODO(toyoshim) Until open() / close() are supported, open each device on
+    // connected.
+    Open();
+    return true;
+  }
+
+  virtual bool Disconnect() {
+    if (info_.state == mojom::PortState::DISCONNECTED)
+      return false;
+    info_.state = mojom::PortState::DISCONNECTED;
+    return true;
+  }
+
+  virtual void NotifyPortAdded(

[yhirano, 2017/02/20 08:02:06]

These two functions need not to be virtual.

[Takashi Toyoshima, 2017/02/20 16:51:59]

Ah, right.
I did so for calling them from Port class, but now the latest code does not need
it any more.

Done.

+      DynamicallyInitializedMidiManagerWin* manager) = 0;
+
+  virtual void NotifyPortStateSet(
+      DynamicallyInitializedMidiManagerWin* manager) = 0;
+
+  virtual void Open() { info_.state = mojom::PortState::OPENED; }
+
+ protected:
+  size_t index_;
+  std::string type_;
+  uint32_t device_id_;
+  const uint16_t manufacturer_id_;
+  const uint16_t product_id_;
+  const uint32_t driver_version_;
+  const std::string product_name_;
+  MidiPortInfo info_;
+};  // class Port
+
+}  // namespace
+
+// TODO(toyoshim): Following patches will implement actual functions.
+class DynamicallyInitializedMidiManagerWin::InPort final : public Port {
+ public:
+  InPort(UINT device_id, const MIDIINCAPS2W& caps)
+      : Port("input",
+             device_id,
+             caps.wMid,
+             caps.wPid,
+             caps.vDriverVersion,
+             base::WideToUTF8(
+                 base::string16(caps.szPname, wcslen(caps.szPname)))) {}
+
+  static std::vector<std::unique_ptr<InPort>> EnumerateActivePorts() {
+    std::vector<std::unique_ptr<InPort>> ports;
+    const UINT num_devices = midiInGetNumDevs();
+    for (UINT device_id = 0; device_id < num_devices; ++device_id) {
+      MIDIINCAPS2W caps;
+      MMRESULT result = midiInGetDevCaps(
+          device_id, reinterpret_cast<LPMIDIINCAPSW>(&caps), sizeof(caps));
+      if (result != MMSYSERR_NOERROR) {
+        LOG(ERROR) << "midiInGetDevCaps fails on device " << device_id;
+        continue;
+      }
+      ports.push_back(base::MakeUnique<InPort>(device_id, caps));
+    }
+    return ports;
+  }
+
+  // Port Overrides:
+  void NotifyPortStateSet(
+      DynamicallyInitializedMidiManagerWin* manager) override {
+    manager->PostReplyTask(
+        base::Bind(&DynamicallyInitializedMidiManagerWin::SetInputPortState,
+                   base::Unretained(manager), index_, info_.state));
+  }
+
+  void NotifyPortAdded(DynamicallyInitializedMidiManagerWin* manager) override {
+    manager->PostReplyTask(
+        base::Bind(&DynamicallyInitializedMidiManagerWin::AddInputPort,
+                   base::Unretained(manager), info_));
+  }
+};
+
+// TODO(toyoshim): Following patches will implement actual functions.
+class DynamicallyInitializedMidiManagerWin::OutPort final : public Port {
+ public:
+  OutPort(UINT device_id, const MIDIOUTCAPS2W& caps)
+      : Port("output",
+             device_id,
+             caps.wMid,
+             caps.wPid,
+             caps.vDriverVersion,
+             base::WideToUTF8(
+                 base::string16(caps.szPname, wcslen(caps.szPname)))),
+        software_(caps.wTechnology == MOD_SWSYNTH) {}
+
+  static std::vector<std::unique_ptr<OutPort>> EnumerateActivePorts() {
+    std::vector<std::unique_ptr<OutPort>> ports;
+    const UINT num_devices = midiOutGetNumDevs();
+    for (UINT device_id = 0; device_id < num_devices; ++device_id) {
+      MIDIOUTCAPS2W caps;
+      MMRESULT result = midiOutGetDevCaps(
+          device_id, reinterpret_cast<LPMIDIOUTCAPSW>(&caps), sizeof(caps));
+      if (result != MMSYSERR_NOERROR) {
+        LOG(ERROR) << "midiOutGetDevCaps fails on device " << device_id;
+        continue;
+      }
+      ports.push_back(base::MakeUnique<OutPort>(device_id, caps));
+    }
+    return ports;
+  }
+
+  // Port overrides:
+  bool Connect() override {
+    // Until |software| option is supported, disable Microsoft GS Wavetable
+    // Synth that has a known security issue.
+    if (software_ && manufacturer_id_ == MM_MICROSOFT &&
+        (product_id_ == MM_MSFT_WDMAUDIO_MIDIOUT ||
+         product_id_ == MM_MSFT_GENERIC_MIDISYNTH)) {
+      return false;
+    }
+    return Port::Connect();
+  }
+
+  // Port Overrides:
+  void NotifyPortStateSet(
+      DynamicallyInitializedMidiManagerWin* manager) override {
+    manager->PostReplyTask(
+        base::Bind(&DynamicallyInitializedMidiManagerWin::SetOutputPortState,
+                   base::Unretained(manager), index_, info_.state));
+  }
+
+  void NotifyPortAdded(DynamicallyInitializedMidiManagerWin* manager) override {
+    manager->PostReplyTask(
+        base::Bind(&DynamicallyInitializedMidiManagerWin::AddOutputPort,
+                   base::Unretained(manager), info_));
+  }
+
+  const bool software_;
+};
+
+DynamicallyInitializedMidiManagerWin::DynamicallyInitializedMidiManagerWin(
+    MidiService* service)
+    : MidiManager(service), instance_id_(IssueNextInstanceId()) {
+  base::AutoLock lock(*GetInstanceIdLock());
+  CHECK_EQ(kInvalidInstanceId, g_active_instance_id);
+
+  // Obtains the task runner for the current thread that hosts this instnace.
+  thread_runner_ = base::ThreadTaskRunnerHandle::Get();
+}
+
+DynamicallyInitializedMidiManagerWin::~DynamicallyInitializedMidiManagerWin() {
+  base::AutoLock lock(*GetInstanceIdLock());
+  CHECK_EQ(kInvalidInstanceId, g_active_instance_id);
+  CHECK(thread_runner_->BelongsToCurrentThread());
+}
+
+void DynamicallyInitializedMidiManagerWin::PostReplyTask(
+    const base::Closure& task) {
+  thread_runner_->PostTask(FROM_HERE, base::Bind(&RunTask, instance_id_, task));
+}
+
+void DynamicallyInitializedMidiManagerWin::StartInitialization() {
+  {
+    base::AutoLock lock(*GetInstanceIdLock());
+    CHECK_EQ(kInvalidInstanceId, g_active_instance_id);
+    g_active_instance_id = instance_id_;
+    CHECK_EQ(nullptr, g_manager_instance);
+    g_manager_instance = this;
+  }
+  // Registers on the I/O thread to be notified on the I/O thread.
+  CHECK(thread_runner_->BelongsToCurrentThread());
+  base::SystemMonitor::Get()->AddDevicesChangedObserver(this);
+
+  // Starts asynchronous initialization on TaskRunner.
+  PostTask(
+      base::Bind(&DynamicallyInitializedMidiManagerWin::InitializeOnTaskRunner,
+                 base::Unretained(this)));
+}
+
+void DynamicallyInitializedMidiManagerWin::Finalize() {
+  // Unregisters on the I/O thread. OnDevicesChanged() won't be called any more.
+  CHECK(thread_runner_->BelongsToCurrentThread());
+  base::SystemMonitor::Get()->RemoveDevicesChangedObserver(this);
+  {
+    base::AutoLock lock(*GetInstanceIdLock());
+    CHECK_EQ(instance_id_, g_active_instance_id);
+    g_active_instance_id = kInvalidInstanceId;
+    CHECK_EQ(this, g_manager_instance);
+    g_manager_instance = nullptr;
+  }
+
+  // Ensures that no task runs on TaskRunner so to destruct the instance safely.
+  // Tasks that did not started yet will do nothing after invalidate the
+  // instance ID above.
+  base::AutoLock lock(*GetTaskLock());
+}
+
+void DynamicallyInitializedMidiManagerWin::DispatchSendMidiData(
+    MidiManagerClient* client,
+    uint32_t port_index,
+    const std::vector<uint8_t>& data,
+    double timestamp) {
+  // TODO(toyoshim): Following patches will implement.
+}
+
+void DynamicallyInitializedMidiManagerWin::OnDevicesChanged(
+    base::SystemMonitor::DeviceType device_type) {
+  // Notified on the I/O thread.
+  CHECK(thread_runner_->BelongsToCurrentThread());
+
+  switch (device_type) {
+    case base::SystemMonitor::DEVTYPE_AUDIO:
+    case base::SystemMonitor::DEVTYPE_VIDEO_CAPTURE:
+      // Add case of other unrelated device types here.
+      return;
+    case base::SystemMonitor::DEVTYPE_UNKNOWN: {
+      PostTask(base::Bind(
+          &DynamicallyInitializedMidiManagerWin::UpdateDeviceListOnTaskRunner,
+          base::Unretained(this)));
+      break;
+    }
+  }
+}
+
+void DynamicallyInitializedMidiManagerWin::PostTask(const base::Closure& task) {
+  service()
+      ->GetTaskRunner(kTaskRunner)
+      ->PostTask(FROM_HERE, base::Bind(&RunTask, instance_id_, task));
+}
+
+void DynamicallyInitializedMidiManagerWin::InitializeOnTaskRunner() {
+  UpdateDeviceListOnTaskRunner();
+  PostReplyTask(
+      base::Bind(&DynamicallyInitializedMidiManagerWin::CompleteInitialization,
+                 base::Unretained(this), mojom::Result::OK));
+}
+
+void DynamicallyInitializedMidiManagerWin::UpdateDeviceListOnTaskRunner() {
+  std::vector<std::unique_ptr<InPort>> active_input_ports =
+      InPort::EnumerateActivePorts();
+  ReflectActiveDeviceList(this, &input_ports_, &active_input_ports);
+
+  std::vector<std::unique_ptr<OutPort>> active_output_ports =
+      OutPort::EnumerateActivePorts();
+  ReflectActiveDeviceList(this, &output_ports_, &active_output_ports);
+
+  // TODO(toyoshim): This method may run before internal MIDI device lists that
+  // Windows manages were updated. This may be because MIDI driver may be loaded
+  // after the raw device list was updated. To avoid this problem, we may want
+  // to retry device check later if no changes are detected here.
+}
+
+template <typename T>
+void DynamicallyInitializedMidiManagerWin::ReflectActiveDeviceList(
+    DynamicallyInitializedMidiManagerWin* manager,
+    T* known_ports,
+    T* active_ports) {
+  // Update existing port states.
+  for (const auto& port : *known_ports) {
+    const auto& it = std::find_if(
+        active_ports->begin(), active_ports->end(),
+        [&port](const auto& candidate) { return *candidate == *port; });
+    if (it == active_ports->end()) {
+      if (port->Disconnect())
+        port->NotifyPortStateSet(this);
+    } else {
+      port->set_device_id((*it)->device_id());
+      if (port->Connect())
+        port->NotifyPortStateSet(this);
+    }
+  }
+

[Takashi Toyoshima, 2017/02/17 17:42:29]

NotifyPortStateSet() or NotifyPortAdded() are called from caller sides.
They could be hidden behind Connect() and Disconnect() methods, but it requires
that port instance has a manager's pointer, new bool flag to call a right
NotifyX method, and dirty logic to handle blacklisted output port correctly.

+  // Find new ports from active ports and append them to known ports.
+  for (auto& port : *active_ports) {
+    if (std::find_if(known_ports->begin(), known_ports->end(),
+                     [&port](const auto& candidate) {
+                       return *candidate == *port;
+                     }) == known_ports->end()) {
+      size_t index = known_ports->size();
+      port->set_index(index);
+      known_ports->push_back(std::move(port));
+      (*known_ports)[index]->Connect();
+      (*known_ports)[index]->NotifyPortAdded(this);
+    }
+  }
+}
+
+}  // namespace midi