[Ozone] Properly initialize multitouch slot values

ui/events/ozone/evdev/event_device_info.cc

Index: ui/events/ozone/evdev/event_device_info.cc
diff --git a/ui/events/ozone/evdev/event_device_info.cc b/ui/events/ozone/evdev/event_device_info.cc
index 6d75ea9e0c7272cb0726c5052ea41e3e12d9dc19..e5311f226757cfebcd099f53cd9e0076fe3f5cbb 100644
--- a/ui/events/ozone/evdev/event_device_info.cc
+++ b/ui/events/ozone/evdev/event_device_info.cc
@@ -13,6 +13,11 @@ namespace ui {
 
 namespace {
 
+struct MTSlotRequest {

[spang, 2014/10/21 19:38:36]

For consistency: MtSlotRequest

(and everywhere else)

[dnicoara, 2014/10/21 20:32:12]

Removed the struct for simplicity.

+  uint32_t code;
+  int32_t* values;

[spang, 2014/10/21 19:38:36]

Should be an array.

+};
+
 bool GetEventBits(int fd, unsigned int type, void* buf, unsigned int size) {
   if (ioctl(fd, EVIOCGBIT(type, size), buf) < 0) {
     DLOG(ERROR) << "failed EVIOCGBIT(" << type << ", " << size << ") on fd "
@@ -40,6 +45,29 @@ bool GetAbsInfo(int fd, int code, struct input_absinfo* absinfo) {
   return true;
 }
 
+bool GetSlotValues(int fd, int code, int32_t* slot_values, unsigned int size) {
+  MTSlotRequest request;
+  request.code = code;
+  request.values = slot_values;
+
+  if (ioctl(fd,
+            EVIOCGMTSLOTS(sizeof(uint32_t) + sizeof(int32_t) * size),
+            &request) < 0) {
+    LOG(ERROR) << "failed EVIOCGMTSLOTS(" << code << ") on fd " << fd;
+    return false;
+  }
+
+  return true;
+}
+
+int IndexToMTCode(int index) {
+  return index + ABS_MT_SLOT + 1;
+}
+
+int MTCodeToIndex(int code) {
+  return code - ABS_MT_SLOT - 1;

[spang, 2014/10/21 19:38:36]

Can you make this a member function:

int32_t* slots = GetMtSlotsForCode(int code);

And DCHECK that code is within range.

[dnicoara, 2014/10/21 20:32:12]

Done.

+}
+
 }  // namespace
 
 EventDeviceInfo::EventDeviceInfo() {
@@ -52,9 +80,14 @@ EventDeviceInfo::EventDeviceInfo() {
   memset(led_bits_, 0, sizeof(led_bits_));
   memset(prop_bits_, 0, sizeof(prop_bits_));
   memset(abs_info_, 0, sizeof(abs_info_));
+  memset(slot_values_, 0, sizeof(slot_values_));
 }
 
-EventDeviceInfo::~EventDeviceInfo() {}
+EventDeviceInfo::~EventDeviceInfo() {
+  for (size_t i = 0; i < arraysize(slot_values_); ++i)
+    if (slot_values_[i])
+      delete[] slot_values_[i];
+}
 
 bool EventDeviceInfo::Initialize(int fd) {
   if (!GetEventBits(fd, 0, ev_bits_, sizeof(ev_bits_)))
@@ -86,6 +119,14 @@ 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;
+  for (unsigned int i = 0; i < ABS_MT_COUNT; ++i) {

[spang, 2014/10/21 19:38:36]

I think this should iterate over codes rather than the index. There's no reason
to have IndexToMTCode.

[dnicoara, 2014/10/21 20:32:12]

Done.

+    slot_values_[i] = new int32[max_num_slots];
+    memset(slot_values_[i], 0, sizeof(int32) * max_num_slots);
+    if (!GetSlotValues(fd, IndexToMTCode(i), slot_values_[i], max_num_slots))
+      return false;
+  }
+
   return true;
 }
 
@@ -145,6 +186,11 @@ int32 EventDeviceInfo::GetAbsMaximum(unsigned int code) const {
   return abs_info_[code].maximum;
 }
 
+int32 EventDeviceInfo::GetSlotValue(unsigned int code,
+                                    unsigned int slot) const {
+  return slot_values_[MTCodeToIndex(code)][slot];
+}
+
 bool EventDeviceInfo::HasAbsXY() const {
   if (HasAbsEvent(ABS_X) && HasAbsEvent(ABS_Y))
     return true;