chromeos: Add ArcInputBridge to components/arc

components/arc/arc_bridge_input_devices.cc

Index: components/arc/arc_bridge_input_devices.cc
diff --git a/components/arc/arc_bridge_input_devices.cc b/components/arc/arc_bridge_input_devices.cc
new file mode 100644
index 0000000000000000000000000000000000000000..114b60000725a6cdd0eead2c38b926a2652ebfdb
--- /dev/null
+++ b/components/arc/arc_bridge_input_devices.cc
@@ -0,0 +1,167 @@
+#include "components/arc/arc_bridge_input_devices.h"
+
+#include "base/logging.h"
+#include "base/time/time.h"
+#include "ui/events/keycodes/dom/keycode_converter.h"
+#include "ui/events/ozone/evdev/keyboard_util_evdev.h"
+
+#include <linux/input.h>
+
+namespace arc {
+
+// BridgeInputDevice
+
+BridgeInputDevice::BridgeInputDevice(base::ScopedFD fd): fd_(fd.Pass()) {}
+
+void BridgeInputDevice::SendEvent(base::TimeDelta time,

[elijahtaylor1, 2015/11/02 22:30:29]

time is highlighted in the code review tool, maybe we could use a more specific
name to avoid confusion with the c library?

[denniskempin, 2015/11/16 18:39:28]

Done.

+                             __u16 type,

[elijahtaylor1, 2015/11/02 22:30:29]

nit: alignment?

[denniskempin, 2015/11/16 18:39:28]

Done.

+                             __u16 code,
+                             __s32 value) {
+  // Luckily Chrome on POSIX and the receiver both use monotonic time for
+  // input events, so we can just fill in the same timestamp.

[elijahtaylor1, 2015/11/02 22:30:29]

on ARC, we had issues with wall time vs system time.  When the machine would
suspend and resume, the Android system time would be out of sync with input
event times.  No solid advice because I'm not looking where these are generated,
but please test when possible this scenario

[denniskempin, 2015/11/16 18:39:28]

I did notice some problems where android will start dropping touch events
because they are 'stale'. I have not figured out why exactly this is happening,
especially since Mouse/Keyboard seem to continue working. That will take some
more digging for a follow up CL I would suggest. I added a todo.

+  struct input_event event;
+  event.time.tv_sec = time.InSeconds();
+  base::TimeDelta remainder =
+      time - 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
+  int num_written = write(fd_.get(), reinterpret_cast<void*>(&event),
+                          sizeof(struct input_event));
+  if (num_written != sizeof(struct input_event)) {
+    LOG(ERROR) << "Can't write to file descriptor";
+  }
+}
+
+void BridgeInputDevice::SendSynReport(base::TimeDelta time) {
+  SendEvent(time, EV_SYN, SYN_REPORT, 0);
+}
+
+// KeyboardBridgeInputDevice
+
+void KeyboardBridgeInputDevice::OnKeyEvent(ui::KeyEvent* event) {

[elijahtaylor1, 2015/11/02 22:30:29]

I feel like we should either include the keyboard and mouse device registration
at startup or not include this code right now

[denniskempin, 2015/11/16 18:39:28]

This comment seems to be on the wrong file but I understand your concern.
The problem is right now the InstanceReady message is sent before any
instance-side services are loaded, so we cannot register devices at that time.
We do not yet have a message for when the services are ready. I'm working on a
CL right now.

+  int native_code =
+      ui::KeycodeConverter::DomCodeToNativeKeycode(event->code());
+
+  __u16 evdev_code = ui::NativeCodeToEvdevCode(native_code);
+  __u32 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;
+  }
+
+  SendEvent(event->time_stamp(), EV_KEY, evdev_code, evdev_value);
+  SendSynReport(event->time_stamp());
+}
+
+// MouseBridgeInputDevice
+
+void MouseBridgeInputDevice::OnMouseEvent(ui::MouseEvent* event) {
+  base::TimeDelta time = event->time_stamp();
+
+  // update location
+  SendEvent(time, EV_ABS, ABS_X, event->x());
+  SendEvent(time, EV_ABS, ABS_Y, event->y());
+
+  // update buttons
+  SendMouseButton(event, ui::EF_LEFT_MOUSE_BUTTON, BTN_LEFT);
+  SendMouseButton(event, ui::EF_RIGHT_MOUSE_BUTTON, BTN_RIGHT);
+  SendMouseButton(event, ui::EF_MIDDLE_MOUSE_BUTTON, BTN_MIDDLE);
+
+  // update scroll wheel
+  if (event->IsMouseWheelEvent()) {
+    ui::MouseWheelEvent* wheel_event =
+        static_cast<ui::MouseWheelEvent*>(event);
+    SendEvent(time, EV_REL, REL_WHEEL, wheel_event->y_offset());
+    SendEvent(time, EV_REL, REL_HWHEEL, wheel_event->x_offset());
+  }
+
+  SendSynReport(time);
+}
+
+void MouseBridgeInputDevice::SendMouseButton(ui::MouseEvent* event, int flag,
+                                        int evdev_code) {
+  if (event->changed_button_flags() & flag) {
+    bool button_value = event->flags() & flag;
+    SendEvent(event->time_stamp(), EV_KEY, evdev_code, (__s32)button_value);
+  }
+}
+
+// TouchscreenBridgeInputDevice
+
+TouchscreenBridgeInputDevice::TouchscreenBridgeInputDevice(base::ScopedFD fd) :
+    BridgeInputDevice(fd.Pass()),
+    current_slot_tracking_ids_(kMaxSlots, kEmptySlot) {}
+
+void TouchscreenBridgeInputDevice::OnTouchEvent(ui::TouchEvent* event) {
+  ui::PointerDetails details = event->pointer_details();
+  base::TimeDelta time = event->time_stamp();
+
+  // find or assing a slot for this tracking id
+  int slot_id = AcquireSlot(event);
+  if (slot_id < 0) {
+    LOG(ERROR) << "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;
+    SendEvent(time, EV_ABS, ABS_MT_SLOT, current_slot_);
+  }
+
+  // update tracking id
+  if (event->type() == ui::ET_TOUCH_PRESSED) {
+    SendEvent(time, EV_ABS, ABS_MT_TRACKING_ID, event->touch_id());
+  } else if (event->type() == ui::ET_TOUCH_RELEASED) {
+    SendEvent(time, EV_ABS, ABS_MT_TRACKING_ID, -1);
+  }
+
+  // update touch information
+  if (event->type() == ui::ET_TOUCH_MOVED ||
+      event->type() == ui::ET_TOUCH_PRESSED) {
+    SendEvent(time, EV_ABS, ABS_MT_POSITION_X, event->x());
+    SendEvent(time, EV_ABS, ABS_MT_POSITION_Y, event->y());
+    SendEvent(time, EV_ABS, ABS_MT_TOUCH_MAJOR, details.radius_x());
+    SendEvent(time, EV_ABS, ABS_MT_TOUCH_MINOR, details.radius_y());
+  }
+  SendSynReport(time);
+}
+
+int TouchscreenBridgeInputDevice::AcquireSlot(ui::TouchEvent* event) {
+  int slot_id;
+  if (event->type() == ui::ET_TOUCH_PRESSED) {
+    slot_id = FindSlot(kEmptySlot);
+  } else {
+    slot_id = FindSlot(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 TouchscreenBridgeInputDevice::FindSlot(int tracking_id) {
+  for (int i = 0; i < kMaxSlots; ++i) {
+    if (current_slot_tracking_ids_[i] == tracking_id) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+}  // namespace arc