[Ozone] Properly initialize multitouch slot values

BUG=424363
NOTRY=true

Review URL: https://codereview.chromium.org/671723002

Cr-Commit-Position: refs/heads/master@{#300680}

ui/events/ozone/evdev/event_device_info.cc

@@ -40,6 +40,24 @@ bool GetAbsInfo(int fd, int code, struct input_absinfo* absinfo) {
   return true;
 }
 
+// |request| needs to be the equivalent to:
+// struct input_mt_request_layout {
+//   uint32_t code;
+//   int32_t values[num_slots];
+// };
+//
+// |size| is num_slots + 1 (for code).
+bool GetSlotValues(int fd, int32_t* request, unsigned int size) {
+  if (ioctl(fd,
+            EVIOCGMTSLOTS(sizeof(int32_t) * size),
+            request) < 0) {
+    LOG(ERROR) << "failed EVIOCGMTSLOTS(" << request[0] << ") on fd " << fd;
+    return false;
+  }
+
+  return true;
+}
+
 }  // namespace
 
 EventDeviceInfo::EventDeviceInfo() {
@@ -86,6 +104,20 @@ bool EventDeviceInfo::Initialize(int fd) {
       if (!GetAbsInfo(fd, i, &abs_info_[i]))
         return false;
 
+  int max_num_slots = abs_info_[ABS_MT_SLOT].maximum + 1;
+  // |request| is MT code + slots.
+  int32_t request[max_num_slots + 1];
+  for (unsigned int i = ABS_MT_SLOT + 1; i < ABS_MAX; ++i) {
+    memset(request, 0, sizeof(request));
+    request[0] = i;
+    if (HasAbsEvent(i))
+      if (!GetSlotValues(fd, request, max_num_slots + 1))
+        return false;
+
+    slot_values_[i - ABS_MT_SLOT - 1].assign(
+        request + 1, request + max_num_slots + 1);
+  }
+
   return true;
 }
 
@@ -145,6 +177,14 @@ int32 EventDeviceInfo::GetAbsMaximum(unsigned int code) const {
   return abs_info_[code].maximum;
 }
 
+int32 EventDeviceInfo::GetSlotValue(unsigned int code,
+                                    unsigned int slot) const {
+  const std::vector<int32_t>& slots = GetMtSlotsForCode(code);
+  DCHECK_LE(0u, slot) << slot << " is an invalid slot";
+  DCHECK_LT(slot, slots.size()) << slot << " is an invalid slot";
+  return slots[slot];
+}
+
 bool EventDeviceInfo::HasAbsXY() const {
   if (HasAbsEvent(ABS_X) && HasAbsEvent(ABS_Y))
     return true;
@@ -182,4 +222,12 @@ bool EventDeviceInfo::IsMappedToScreen() const {
   return true;
 }
 
+const std::vector<int32_t>& EventDeviceInfo::GetMtSlotsForCode(int code) const {
+  int index = code - ABS_MT_SLOT - 1;
+  DCHECK_LE(0, index) << code << " is not a valid multi-touch code";
+  DCHECK_LT(index, EVDEV_ABS_MT_COUNT)
+      << code << " is not a valid multi-touch code";
+  return slot_values_[index];
+}
+
 }  // namespace ui

ui/events/ozone/evdev/event_device_info.h

@@ -8,10 +8,15 @@
 #include <limits.h>
 #include <linux/input.h>
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "ui/events/ozone/evdev/event_device_util.h"
 #include "ui/events/ozone/evdev/events_ozone_evdev_export.h"
 
+// ABS_MT_SLOT isn't valid options for EVIOCGMTSLOTS ioctl.
+#define EVDEV_ABS_MT_COUNT (ABS_MAX - ABS_MT_SLOT - 1)
+
 namespace ui {
 
 // Device information for Linux input devices
@@ -38,6 +43,7 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
   // Properties of absolute axes.
   int32 GetAbsMinimum(unsigned int code) const;
   int32 GetAbsMaximum(unsigned int code) const;
+  int32 GetSlotValue(unsigned int code, unsigned int slot) const;
 
   // Check input device properties.
   bool HasProp(unsigned int code) const;
@@ -53,6 +59,9 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
   bool IsMappedToScreen() const;
 
  private:
+  // Return the slot vector in |slot_values_| for |code|.
+  const std::vector<int32_t>& GetMtSlotsForCode(int code) const;
+
   unsigned long ev_bits_[EVDEV_BITS_TO_LONGS(EV_CNT)];
   unsigned long key_bits_[EVDEV_BITS_TO_LONGS(KEY_CNT)];
   unsigned long rel_bits_[EVDEV_BITS_TO_LONGS(REL_CNT)];
@@ -64,6 +73,9 @@ class EVENTS_OZONE_EVDEV_EXPORT EventDeviceInfo {
 
   struct input_absinfo abs_info_[ABS_CNT];
 
+  // Store the values for the multi-touch properties for each slot.
+  std::vector<int32_t> slot_values_[EVDEV_ABS_MT_COUNT];
+
   DISALLOW_COPY_AND_ASSIGN(EventDeviceInfo);
 };
 

ui/events/ozone/evdev/touch_event_converter_evdev.cc

@@ -72,6 +72,17 @@ float TuxelToPixelSize(float val, float num_tuxels, float num_pixels) {
 
 namespace ui {
 
+TouchEventConverterEvdev::InProgressEvents::InProgressEvents()
+    : x_(0),
+      y_(0),
+      id_(-1),
+      finger_(-1),
+      type_(ET_UNKNOWN),
+      radius_x_(0),
+      radius_y_(0),
+      pressure_(0) {
+}
+
 TouchEventConverterEvdev::TouchEventConverterEvdev(
     int fd,
     base::FilePath path,
@@ -129,6 +140,19 @@ void TouchEventConverterEvdev::Init(const EventDeviceInfo& info) {
                                 cal.bezel_right,
                                 cal.bezel_top,
                                 cal.bezel_bottom);
+
+  for (int i = 0;
+       i < std::min<int>(info.GetAbsMaximum(ABS_MT_SLOT) + 1, MAX_FINGERS);
+       ++i) {
+    events_[i].finger_ = info.GetSlotValue(ABS_MT_TRACKING_ID, i);
+    events_[i].type_ =
+        events_[i].finger_ < 0 ? ET_TOUCH_RELEASED : ET_TOUCH_PRESSED;
+    events_[i].x_ = info.GetSlotValue(ABS_MT_POSITION_X, i);
+    events_[i].y_ = info.GetSlotValue(ABS_MT_POSITION_Y, i);
+    events_[i].radius_x_ = info.GetSlotValue(ABS_MT_TOUCH_MAJOR, i);
+    events_[i].radius_y_ = info.GetSlotValue(ABS_MT_TOUCH_MINOR, i);
+    events_[i].pressure_ = info.GetSlotValue(ABS_MT_PRESSURE, i);
+  }
 }
 
 bool TouchEventConverterEvdev::Reinitialize() {

ui/events/ozone/evdev/touch_event_converter_evdev.h

@@ -93,6 +93,8 @@ class EVENTS_OZONE_EVDEV_EXPORT TouchEventConverterEvdev
   std::bitset<MAX_FINGERS> altered_slots_;
 
   struct InProgressEvents {
+    InProgressEvents();
+
     float x_;
     float y_;
     int id_;  // Device reported "unique" touch point id; -1 means not active