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..bbab636debc06a5eb7594398e5c9ec3e98156273
--- /dev/null
+++ b/components/arc/arc_bridge_input_devices.cc
@@ -0,0 +1,193 @@
+#include "components/arc/arc_bridge_input_devices.h"

[Luis Héctor Chávez, 2015/11/17 17:51:53]

Also missing copyright block.

[denniskempin, 2015/11/19 19:22:08]

Done.

+
+#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>

[Luis Héctor Chávez, 2015/11/17 17:51:53]

Convention seems to be to put the system includes before the Chrome ones.

[denniskempin, 2015/11/19 19:22:08]

Done.

+
+namespace arc {
+
+namespace {
+static const int y_offset = 32;

[elijahtaylor1, 2015/11/16 21:08:26]

comment on this, specifically about it being temp or not and how we want to
workaround the decoration more dynamically?  also, I thought chromium constants
were kYOffset style

[denniskempin, 2015/11/19 19:22:08]

oops. this line should be part of the HACK CL. I don't want this in here but we
needed it for the demo. 

+}
+
+// BridgeInputDevice
+
+BridgeInputDevice::BridgeInputDevice(base::ScopedFD fd) : fd_(fd.Pass()) {}
+
+void BridgeInputDevice::SendEvent(base::TimeDelta timestamp,
+                                  __u16 type,
+                                  __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.
+  // todo(denniskempin): Nevertheless there are rare issues with stale events on
+  // the instance side.
+  struct input_event event;
+  event.time.tv_sec = timestamp.InSeconds();
+  base::TimeDelta remainder =
+      timestamp - 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),

[Luis Héctor Chávez, 2015/11/17 17:51:53]

Can you add a thread check to make sure you are not doing I/O on non-IO threads?
Also add comments on all functions in the .h about what thread they can be used
on.

[denniskempin, 2015/11/19 19:22:08]

I'll have to look into that. I did not know we can't do IO from the main thread.

+                          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
+
+KeyboardBridgeInputDevice::KeyboardBridgeInputDevice(base::ScopedFD fd)
+    : BridgeInputDevice(fd.Pass()) {}
+
+void KeyboardBridgeInputDevice::OnKeyEvent(ui::KeyEvent* event) {
+  int native_code = ui::KeycodeConverter::DomCodeToNativeKeycode(event->code());
+
+  __u16 evdev_code = ui::NativeCodeToEvdevCode(native_code);

[Luis Héctor Chávez, 2015/11/17 17:51:53]

Huh, this does not need a cast?

[denniskempin, 2015/11/19 19:22:08]

I expected the method to return a u16 which is the type of evdev codes. This
should cause at least a warning but nothing shows up. that's interesting. Either
way, I updated the code to use standard integer types instead. 

+  __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
+
+MouseBridgeInputDevice::MouseBridgeInputDevice(base::ScopedFD fd)
+    : BridgeInputDevice(fd.Pass()) {}
+
+void MouseBridgeInputDevice::OnMouseEvent(ui::MouseEvent* event) {
+  base::TimeDelta time = event->time_stamp();
+  if (event->y() - y_offset < 0) {
+    return;
+  }
+
+  // update location
+  if (event->type() == ui::ET_MOUSE_MOVED) {
+    SendEvent(time, EV_ABS, ABS_X, event->x());

[elijahtaylor1, 2015/11/16 21:08:26]

is there no decoration on the x side that needs to be adjusted? why does y need
adjusted, is the title bar being rendered in the window instead of actually
being rendered by the system?

[denniskempin, 2015/11/19 19:22:08]

See above. We did not see any offset in the X direction. We had to attach the
event handler to the window itself, so we get events relative to the window
frame. If we put the event handler into the client area we do not get all
events. I am not quite sure why that is, I will have to talk to someone who
knows more about input routing in chrome. 

+    SendEvent(time, EV_ABS, ABS_Y, event->y() - y_offset);
+  }
+
+  // update buttons
+  if (event->type() == ui::ET_MOUSE_PRESSED ||
+      event->type() == ui::ET_MOUSE_RELEASED) {
+    bool button_value = event->type() == ui::ET_MOUSE_PRESSED;
+    SendMouseButton(event, ui::EF_LEFT_MOUSE_BUTTON, BTN_LEFT, button_value);

[elijahtaylor1, 2015/11/16 21:08:26]

this is a weird structure.  Some of the |event| checking is happening in this
function and some in SendMouseButton.  It's also weird to have this function
call "SendMouseButton" but it's not clear that it will actually have an effect.

I think it would make more sense to either just have a separate function called
"UpdateButtons" or something and do all this logic there, looping over the
buttons and checking flags individually.

[denniskempin, 2015/11/19 19:22:08]

I agree. It made sense in the beginning, not anymore. updated to loop over a
static array. 

+    SendMouseButton(event, ui::EF_RIGHT_MOUSE_BUTTON, BTN_RIGHT, button_value);
+    SendMouseButton(event, ui::EF_MIDDLE_MOUSE_BUTTON, BTN_MIDDLE,
+                    button_value);
+  }
+
+  // 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,
+                                             bool button_value) {
+  if (event->changed_button_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),
+      current_slot_(-1) {}
+
+void TouchscreenBridgeInputDevice::OnTouchEvent(ui::TouchEvent* event) {
+  ui::PointerDetails details = event->pointer_details();
+  base::TimeDelta time = event->time_stamp();
+  if (event->y() - y_offset < 0) {
+    return;
+  }
+
+  // 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() - y_offset);
+    SendEvent(time, EV_ABS, ABS_MT_TOUCH_MAJOR, details.radius_x());
+    SendEvent(time, EV_ABS, ABS_MT_TOUCH_MINOR, details.radius_y());
+    SendEvent(time, EV_ABS, ABS_MT_PRESSURE, 100);

[elijahtaylor1, 2015/11/16 21:08:26]

what is 100?

[denniskempin, 2015/11/19 19:22:08]

a hack. Updated to use force(). 

+  }
+  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