chromeos: Add ArcInputBridge to components/arc

components/arc/input/arc_input_bridge_impl.cc

+// Copyright 2015 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 "components/arc/input/arc_input_bridge_impl.h"
+
+#include <linux/input.h>
+#include <fcntl.h>
+
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/time/time.h"
+#include "components/arc/arc_bridge_service.h"
+#include "ui/aura/env.h"
+#include "ui/aura/env_observer.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_observer.h"
+#include "ui/events/event.h"
+#include "ui/events/event_handler.h"
+#include "ui/events/event_utils.h"
+#include "ui/events/keycodes/dom/keycode_converter.h"
+
+namespace {
+
+// input_event values for keyboard events.
+const int kKeyReleased = 0;
+const int kKeyPressed = 1;
+const int kKeyRepeated = 2;
+
+// maximum number of supported multi-touch slots (simultaneous fingers).
+const int kMaxSlots = 64;
+
+// tracking id of an empty slot.
+const int kEmptySlot = -1;
+
+// maximum possible pressure as defined in EventHubARC.
+// TODO(denniskempin): communicate maximum during initialization.
+const int kMaxPressure = 65536;
+
+// speed of the scroll emulation. Scroll events are reported at about 100 times
+// the speed of a scroll wheel.
+const float kScrollEmulationSpeed = 100.0f;
+
+struct MouseButtonMapping {
+  int ui_flag;
+  int evdev_code;
+} kMouseButtonMap[] = {
+    {ui::EF_LEFT_MOUSE_BUTTON, BTN_LEFT},
+    {ui::EF_RIGHT_MOUSE_BUTTON, BTN_RIGHT},
+    {ui::EF_MIDDLE_MOUSE_BUTTON, BTN_MIDDLE},
+};
+
+// Offset between evdev key codes and chrome native key codes
+const int kXkbKeycodeOffset = 8;
+
+}  // namespace
+
+namespace arc {
+
+ArcInputBridgeImpl::ArcInputBridgeImpl(ArcBridgeService* arc_bridge_service)
+    : arc_bridge_service_(arc_bridge_service),
+      offset_x_acc_(0.5f),
+      offset_y_acc_(0.5f),
+      current_slot_(-1),
+      current_slot_tracking_ids_(kMaxSlots, kEmptySlot),
+      origin_task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      weak_factory_(this) {
+  DCHECK(arc_bridge_service->state() == ArcBridgeService::State::STOPPED);
+  arc_bridge_service->AddObserver(this);
+
+  DCHECK(aura::Env::GetInstance());
+  aura::Env::GetInstance()->AddObserver(this);
+}
+
+ArcInputBridgeImpl::~ArcInputBridgeImpl() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  arc_bridge_service_->RemoveObserver(this);
+  aura::Env::GetInstance()->RemoveObserver(this);
+
+  for (aura::Window* window : arc_windows_.windows()) {
+    window->RemovePreTargetHandler(this);
+  }
+}
+
+void ArcInputBridgeImpl::OnInstanceBootPhase(InstanceBootPhase phase) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (phase != INSTANCE_BOOT_PHASE_SYSTEM_SERVICES_READY)
+    return;
+
+  keyboard_fd_ = CreateBridgeInputDevice("ChromeOS Keyboard", "keyboard");
+  mouse_fd_ = CreateBridgeInputDevice("ChromeOS Mouse", "mouse");
+  touchscreen_fd_ =
+      CreateBridgeInputDevice("ChromeOS Touchscreen", "touchscreen");
+}
+
+// Translates and sends a ui::Event to the appropriate bridge device of the
+// ARC instance. If the devices have not yet been initialized, the event
+// will be ignored.
+void ArcInputBridgeImpl::OnEvent(ui::Event* event) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (event->IsKeyEvent()) {
+    SendKeyEvent(static_cast<ui::KeyEvent*>(event));
+  } else if (event->IsMouseEvent() || event->IsScrollEvent()) {
+    SendMouseEvent(static_cast<ui::MouseEvent*>(event));
+  } else if (event->IsTouchEvent()) {
+    SendTouchEvent(static_cast<ui::TouchEvent*>(event));
+  }
+}
+
+// Attaches the input bridge to the window if it is marked as an ARC window.
+void ArcInputBridgeImpl::OnWindowInitialized(aura::Window* new_window) {
+  if (new_window->name() == "ExoSurface") {

[reveman, 2015/12/08 17:02:08]

Fyi, as an alternative to this you can now use
exo::Surface::AsSurface(aura_window) to determine if a surface is an exo surface
or not. However, this is not going to be set at the time OnWindowInitialized is
called so you'd have to either observe each window for property changes or just
install the pre-target handler for the root window and then check at dispatch
time if it's a exo surface or not.

The best would be to switch over to using exo::Pointer, exo::Keyboard and
exo::Touch once all the code for those classes have landed.

+    arc_windows_.Add(new_window);
+    new_window->AddPreTargetHandler(this);
+  }
+}
+
+void ArcInputBridgeImpl::SendKeyEvent(ui::KeyEvent* event) {
+  if (keyboard_fd_.get() < 0) {
+    VLOG(2) << "No keyboard bridge device available.";
+    return;
+  }
+
+  unsigned short evdev_code = DomCodeToEvdevCode(event->code());
+  int evdev_value;
+  if (event->type() == ui::ET_KEY_PRESSED) {
+    if (event->flags() & ui::EF_IS_REPEAT) {
+      evdev_value = kKeyRepeated;
+    } else {
+      evdev_value = kKeyPressed;
+    }
+  } else if (event->type() == ui::ET_KEY_RELEASED) {
+    evdev_value = kKeyReleased;
+  }
+
+  base::TimeDelta time_stamp = event->time_stamp();
+  SendKernelEvent(keyboard_fd_, time_stamp, EV_KEY, evdev_code, evdev_value);
+  SendSynReport(keyboard_fd_, time_stamp);
+}
+
+void ArcInputBridgeImpl::SendTouchEvent(ui::TouchEvent* event) {
+  if (touchscreen_fd_.get() < 0) {
+    VLOG(2) << "No touchscreen bridge device available.";
+    return;
+  }
+
+  ui::PointerDetails details = event->pointer_details();
+  base::TimeDelta time_stamp = event->time_stamp();
+
+  // find or assing a slot for this tracking id
+  int slot_id = AcquireTouchSlot(event);
+  if (slot_id < 0) {
+    VLOG(1) << "Ran out of slot IDs.";
+    return;
+  }
+
+  // we only need to send the slot ID when it has changed.
+  if (slot_id != current_slot_) {
+    current_slot_ = slot_id;
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_SLOT,
+                    current_slot_);
+  }
+
+  // update tracking id
+  if (event->type() == ui::ET_TOUCH_PRESSED) {
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_TRACKING_ID,
+                    event->touch_id());
+  } else if (event->type() == ui::ET_TOUCH_RELEASED) {
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_TRACKING_ID,
+                    kEmptySlot);
+  }
+
+  // update touch information
+  if (event->type() == ui::ET_TOUCH_MOVED ||
+      event->type() == ui::ET_TOUCH_PRESSED) {
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_POSITION_X,
+                    event->x());
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_POSITION_Y,
+                    event->y());
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_TOUCH_MAJOR,
+                    details.radius_x());
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_TOUCH_MINOR,
+                    details.radius_y());
+    SendKernelEvent(touchscreen_fd_, time_stamp, EV_ABS, ABS_MT_PRESSURE,
+                    details.force() * kMaxPressure);
+  }
+  SendSynReport(touchscreen_fd_, time_stamp);
+}
+
+void ArcInputBridgeImpl::SendMouseEvent(ui::MouseEvent* event) {
+  if (mouse_fd_.get() < 0) {
+    VLOG(2) << "No mouse bridge device available.";
+    return;
+  }
+
+  base::TimeDelta time_stamp = event->time_stamp();
+
+  // update location
+  if (event->type() == ui::ET_MOUSE_MOVED ||
+      event->type() == ui::ET_MOUSE_DRAGGED) {
+    SendKernelEvent(mouse_fd_, time_stamp, EV_ABS, ABS_X, event->x());
+    SendKernelEvent(mouse_fd_, time_stamp, EV_ABS, ABS_Y, event->y());
+  }
+
+  // update buttons
+  if (event->type() == ui::ET_MOUSE_PRESSED ||
+      event->type() == ui::ET_MOUSE_RELEASED) {
+    int evdev_value = static_cast<int>(event->type() == ui::ET_MOUSE_PRESSED);
+    for (MouseButtonMapping mapping : kMouseButtonMap) {
+      if (event->changed_button_flags() & mapping.ui_flag) {
+        SendKernelEvent(mouse_fd_, time_stamp, EV_KEY, mapping.evdev_code,
+                        evdev_value);
+      }
+    }
+  }
+
+  // update scroll wheel
+  if (event->type() == ui::ET_SCROLL) {
+    ui::ScrollEvent* scroll_event = static_cast<ui::ScrollEvent*>(event);
+    // accumulate floating point scroll offset since we can only send full
+    // integer
+    // wheel events.
+    offset_x_acc_ += scroll_event->x_offset_ordinal() / kScrollEmulationSpeed;
+    offset_y_acc_ += scroll_event->y_offset_ordinal() / kScrollEmulationSpeed;
+
+    int wheel = floor(offset_y_acc_);
+    if (wheel != 0) {
+      SendKernelEvent(mouse_fd_, time_stamp, EV_REL, REL_WHEEL, wheel);
+      offset_y_acc_ -= static_cast<float>(wheel);
+    }
+
+    int hwheel = floor(offset_x_acc_);
+    if (hwheel != 0) {
+      SendKernelEvent(mouse_fd_, time_stamp, EV_REL, REL_HWHEEL, hwheel);
+      offset_x_acc_ -= static_cast<float>(hwheel);
+    }
+  }
+
+  SendSynReport(mouse_fd_, time_stamp);
+}
+
+void ArcInputBridgeImpl::SendKernelEvent(const base::ScopedFD& fd,
+                                         base::TimeDelta time_stamp,
+                                         unsigned short type,
+                                         unsigned short code,
+                                         int value) {
+  DCHECK(fd.is_valid());
+
+  // Chrome does not always use the monotonic system time for event times.
+  // For now always force the event time to the current system time.
+  // TODO(denniskempin): To enable performance tracing of events we will want
+  // to use the kernel-provided monotonic time stamps of events.
+  time_stamp = ui::EventTimeForNow();
+
+  struct input_event event;
+  event.time.tv_sec = time_stamp.InSeconds();
+  base::TimeDelta remainder =
+      time_stamp - base::TimeDelta::FromSeconds(event.time.tv_sec);
+  event.time.tv_usec = remainder.InMicroseconds();
+  event.type = type;
+  event.code = code;
+  event.value = value;
+
+  // Write event to file descriptor
+  size_t num_written = write(fd.get(), reinterpret_cast<void*>(&event),
+                             sizeof(struct input_event));
+  DCHECK_EQ(num_written, sizeof(struct input_event));
+}
+
+void ArcInputBridgeImpl::SendSynReport(const base::ScopedFD& fd,
+                                       base::TimeDelta time) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+
+  SendKernelEvent(fd, time, EV_SYN, SYN_REPORT, 0);
+}
+
+int ArcInputBridgeImpl::AcquireTouchSlot(ui::TouchEvent* event) {
+  int slot_id;
+  if (event->type() == ui::ET_TOUCH_PRESSED) {
+    slot_id = FindTouchSlot(kEmptySlot);
+  } else {
+    slot_id = FindTouchSlot(event->touch_id());
+  }
+  if (slot_id < 0) {
+    return -1;
+  }
+
+  if (event->type() == ui::ET_TOUCH_RELEASED) {
+    current_slot_tracking_ids_[slot_id] = kEmptySlot;
+  } else if (event->type() == ui::ET_TOUCH_PRESSED) {
+    current_slot_tracking_ids_[slot_id] = event->touch_id();
+  }
+  return slot_id;
+}
+
+int ArcInputBridgeImpl::FindTouchSlot(int tracking_id) {
+  for (int i = 0; i < kMaxSlots; ++i) {
+    if (current_slot_tracking_ids_[i] == tracking_id) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+unsigned short ArcInputBridgeImpl::DomCodeToEvdevCode(ui::DomCode dom_code) {
+  int native_code = ui::KeycodeConverter::DomCodeToNativeKeycode(dom_code);
+  if (native_code == ui::KeycodeConverter::InvalidNativeKeycode())
+    return KEY_RESERVED;
+
+  return native_code - kXkbKeycodeOffset;
+}
+
+base::ScopedFD ArcInputBridgeImpl::CreateBridgeInputDevice(
+    const std::string& name,
+    const std::string& device_type) {
+  if (!arc_bridge_service_) {
+    VLOG(1) << "ArcBridgeService disappeared.";
+    return base::ScopedFD();
+  }
+
+  // Create file descriptor pair for communication
+  int fd[2];
+  int res = HANDLE_EINTR(pipe(fd));
+  if (res < 0) {
+    VPLOG(1) << "Cannot create pipe";
+    return base::ScopedFD();
+  }
+  base::ScopedFD read_fd(fd[0]);
+  base::ScopedFD write_fd(fd[1]);
+
+  // The read end is sent to the instance, ownership of fd transfers.
+  if (!arc_bridge_service_->RegisterInputDevice(name, device_type,
+                                                std::move(read_fd))) {
+    VLOG(1) << "Cannot create bridge input device";
+    return base::ScopedFD();
+  }
+
+  // setup write end as non blocking
+  int flags = HANDLE_EINTR(fcntl(write_fd.get(), F_GETFL, 0));
+  if (res < 0) {
+    VPLOG(1) << "Cannot get file descriptor flags";
+    return base::ScopedFD();
+  }
+
+  res = HANDLE_EINTR(fcntl(write_fd.get(), F_SETFL, flags | O_NONBLOCK));
+  if (res < 0) {
+    VPLOG(1) << "Cannot set file descriptor flags";
+    return base::ScopedFD();
+  }
+  return std::move(write_fd);
+}
+
+scoped_ptr<ArcInputBridge> ArcInputBridge::Create(
+    ArcBridgeService* arc_bridge_service) {
+  return make_scoped_ptr(new ArcInputBridgeImpl(arc_bridge_service));
+}
+
+}  // namespace arc