Implemented smooth scrolling using xinput2 in X11.

ui/events/devices/x11/device_data_manager_x11.cc

Index: ui/events/devices/x11/device_data_manager_x11.cc
diff --git a/ui/events/devices/x11/device_data_manager_x11.cc b/ui/events/devices/x11/device_data_manager_x11.cc
index 85704437dfd2a84923762d0c9d770d7f18649661..22cbeadc91e8dad7c27042177911f95b7b7bff95 100644
--- a/ui/events/devices/x11/device_data_manager_x11.cc
+++ b/ui/events/devices/x11/device_data_manager_x11.cc
@@ -209,6 +209,8 @@ void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
     data_type_lookup_[i].clear();
     valuator_min_[i].clear();
     valuator_max_[i].clear();
+    scroll_data_[i].horizontal.number = -1;
+    scroll_data_[i].vertical.number = -1;
     for (int j = 0; j < kMaxSlotNum; j++)
       last_seen_valuator_[i][j].clear();
   }
@@ -264,21 +266,15 @@ void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
     for (int j = 0; j < kMaxSlotNum; j++)
       last_seen_valuator_[deviceid][j].resize(DT_LAST_ENTRY, 0);
     for (int j = 0; j < info.num_classes; ++j) {
-      if (info.classes[j]->type != XIValuatorClass)
-        continue;
-
-      XIValuatorClassInfo* v =
-          reinterpret_cast<XIValuatorClassInfo*>(info.classes[j]);
-      for (int data_type = 0; data_type < DT_LAST_ENTRY; ++data_type) {
-        if (v->label == atoms[data_type]) {
-          valuator_lookup_[deviceid][data_type] = v->number;
-          data_type_lookup_[deviceid][v->number] = data_type;
-          valuator_min_[deviceid][data_type] = v->min;
-          valuator_max_[deviceid][data_type] = v->max;
-          if (IsCMTDataType(data_type))
-            possible_cmt = true;
-          break;
-        }
+      if (info.classes[j]->type == XIValuatorClass) {
+        if (UpdateValuatorClassDevice(
+            reinterpret_cast<XIValuatorClassInfo*>(info.classes[j]),
+            atoms,
+            deviceid))
+          possible_cmt = true;
+      } else if (info.classes[j]->type == XIScrollClass) {
+        UpdateScrollClassDevice(
+            reinterpret_cast<XIScrollClassInfo*>(info.classes[j]), deviceid);
       }
     }
 
@@ -287,6 +283,44 @@ void DeviceDataManagerX11::UpdateDeviceList(Display* display) {
   }
 }
 
+bool DeviceDataManagerX11::UpdateValuatorClassDevice(
+    XIValuatorClassInfo* valuator_class_info,
+    Atom *atoms,
+    int deviceid) {

[sadrul, 2015/08/18 16:57:45]

Add a DCHECK here that deviceid is valid.

[Will Shackleton, 2015/08/26 19:52:48]

Acknowledged.

+  for (int data_type = 0; data_type < DT_LAST_ENTRY; ++data_type) {
+    if (valuator_class_info->label == atoms[data_type]) {
+      valuator_lookup_[deviceid][data_type] = valuator_class_info->number;
+      data_type_lookup_[deviceid][valuator_class_info->number] = data_type;
+      valuator_min_[deviceid][data_type] = valuator_class_info->min;
+      valuator_max_[deviceid][data_type] = valuator_class_info->max;
+      if (IsCMTDataType(data_type))

[sadrul, 2015/08/18 16:57:45]

Can you clarify why cmt-data type matters here?

[Will Shackleton, 2015/08/26 19:52:48]

This method is moved from above (line 279, left) - I was instructed to refactor
this code to make this part easier to read.

+        return true;
+    }
+  }
+  return false;
+}
+
+void DeviceDataManagerX11::UpdateScrollClassDevice(
+    XIScrollClassInfo* scroll_class_info,
+    int deviceid) {

[sadrul, 2015/08/18 16:57:45]

DCHECK for deviceid

[Will Shackleton, 2015/08/26 19:52:48]

Acknowledged.

+  ScrollInfo& info = scroll_data_[deviceid];
+  switch (scroll_class_info->scroll_type) {
+    case XIScrollTypeVertical:
+      info.vertical.number = scroll_class_info->number;
+      info.vertical.increment = scroll_class_info->increment;
+      info.vertical.position = 0;
+      info.vertical.seen = false;
+      break;
+    case XIScrollTypeHorizontal:
+      info.horizontal.number = scroll_class_info->number;
+      info.horizontal.increment = scroll_class_info->increment;
+      info.horizontal.position = 0;
+      info.horizontal.seen = false;
+      break;
+  }
+  scrollclass_devices_[deviceid] = true;
+}
+
 bool DeviceDataManagerX11::GetSlotNumber(const XIDeviceEvent* xiev, int* slot) {
   ui::TouchFactory* factory = ui::TouchFactory::GetInstance();
   if (!factory->IsMultiTouchDevice(xiev->sourceid)) {
@@ -409,6 +443,40 @@ bool DeviceDataManagerX11::IsCMTDeviceEvent(
   return cmt_devices_[xievent->sourceid];
 }
 
+int DeviceDataManagerX11::GetScrollClassEventDetail(const base::NativeEvent&
+    native_event) const {
+  if (native_event->type != GenericEvent)
+    return SCROLL_TYPE_NO_SCROLL;
+
+  XIDeviceEvent* xievent =
+      static_cast<XIDeviceEvent*>(native_event->xcookie.data);
+  if (xievent->sourceid >= kMaxDeviceNum)
+    return SCROLL_TYPE_NO_SCROLL;
+  if (!scrollclass_devices_[xievent->sourceid])
+    return SCROLL_TYPE_NO_SCROLL;
+  int horizontal_id = scroll_data_[xievent->sourceid].horizontal.number;
+  int vertical_id = scroll_data_[xievent->sourceid].vertical.number;
+  return (XIMaskIsSet(xievent->valuators.mask, horizontal_id) ?
+      SCROLL_TYPE_HORIZONTAL : 0) |
+    (XIMaskIsSet(xievent->valuators.mask, vertical_id) ?
+     SCROLL_TYPE_VERTICAL : 0);
+}
+
+int DeviceDataManagerX11::GetScrollClassDeviceDetail(
+    const base::NativeEvent& native_event) const {
+  XEvent& xev = *native_event;
+  if (xev.type != GenericEvent)
+    return SCROLL_TYPE_NO_SCROLL;
+
+  XIDeviceEvent* xiev = static_cast<XIDeviceEvent*>(xev.xcookie.data);
+  if (xiev->sourceid >= kMaxDeviceNum || xiev->deviceid >= kMaxDeviceNum)
+    return SCROLL_TYPE_NO_SCROLL;
+  const int sourceid = xiev->sourceid;
+  ScrollInfo device_data = scroll_data_[sourceid];
+  return (device_data.vertical.number >= 0 ? SCROLL_TYPE_VERTICAL : 0) |
+    (device_data.horizontal.number >= 0 ? SCROLL_TYPE_HORIZONTAL : 0);
+}
+
 bool DeviceDataManagerX11::IsCMTGestureEvent(
     const base::NativeEvent& native_event) const {
   return (IsScrollEvent(native_event) ||
@@ -496,6 +564,64 @@ void DeviceDataManagerX11::GetScrollOffsets(
     *finger_count = static_cast<int>(data[DT_CMT_FINGER_COUNT]);
 }
 
+void DeviceDataManagerX11::GetScrollClassOffsets(
+    const base::NativeEvent& native_event,
+    double* x_offset,
+    double* y_offset) {
+  XEvent& xev = *native_event;
+  if (xev.type != GenericEvent)
+    return;
+
+  *x_offset = 0;
+  *y_offset = 0;
+
+  XIDeviceEvent* xiev = static_cast<XIDeviceEvent*>(xev.xcookie.data);
+  if (xiev->sourceid >= kMaxDeviceNum || xiev->deviceid >= kMaxDeviceNum)
+    return;
+  const int sourceid = xiev->sourceid;
+  double* valuators = xiev->valuators.values;
+
+  ScrollInfo& info = scroll_data_[sourceid];
+
+  const int horizontal_number = info.horizontal.number;
+  const int vertical_number = info.vertical.number;
+
+  for (int i = 0; i <= valuator_count_[sourceid]; ++i) {
+    if (XIMaskIsSet(xiev->valuators.mask, i)) {

[sadrul, 2015/08/18 16:57:45]

if (!mask-set) continue;

[Will Shackleton, 2015/08/26 19:52:48]

Acknowledged.

+      if (i == horizontal_number) {
+        double value = *valuators;
+        double delta = 0;
+
+        if (info.horizontal.seen)
+          delta = info.horizontal.position - value;
+
+        info.horizontal.seen = true;
+        info.horizontal.position = value;
+        *x_offset = delta;
+        NormalizeScrollData(sourceid, true, x_offset);
+      } else if (i == vertical_number) {
+        double value = *valuators;
+        double delta = 0;
+        if (info.vertical.seen)
+          delta = info.vertical.position - value;
+
+        info.vertical.seen = true;
+        info.vertical.position = value;
+        *y_offset = delta;
+        NormalizeScrollData(sourceid, false, y_offset);
+      }
+      valuators++;
+    }
+  }
+}
+
+void DeviceDataManagerX11::InvalidateScrollClasses() {
+  for (int i = 0; i < kMaxDeviceNum; i++) {
+    scroll_data_[i].horizontal.seen = false;
+    scroll_data_[i].vertical.seen = false;
+  }
+}
+
 void DeviceDataManagerX11::GetFlingData(
     const base::NativeEvent& native_event,
     float* vx,
@@ -589,6 +715,23 @@ bool DeviceDataManagerX11::NormalizeData(int deviceid,
   return false;
 }
 
+bool DeviceDataManagerX11::NormalizeScrollData(unsigned int deviceid,
+                                         bool horizontal,
+                                         double* value) {
+  if (deviceid >= static_cast<unsigned int>(kMaxDeviceNum))
+    return false;
+  if (horizontal && scroll_data_[deviceid].horizontal.number < 0)
+    return false;
+  if (!horizontal && scroll_data_[deviceid].vertical.number < 0)
+    return false;
+  double increment = horizontal ?
+    scroll_data_[deviceid].horizontal.increment :
+    scroll_data_[deviceid].vertical.increment;
+
+  *value /= increment;
+  return true;
+}
+
 bool DeviceDataManagerX11::GetDataRange(int deviceid,
                                         const DataType type,
                                         double* min,