evdev: Fix crashing with touch devices

ui/events/ozone/evdev/event_device_info.h

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_EVENTS_OZONE_EVDEV_EVENT_DEVICE_INFO_H_
+#define UI_EVENTS_OZONE_EVDEV_EVENT_DEVICE_INFO_H_
+
+#include <limits.h>
+#include <linux/input.h>
+
+#include "base/basictypes.h"
+
+#define EVDEV_LONG_BITS (CHAR_BIT * sizeof(long))
+#define EVDEV_BITS_TO_LONGS(x) (((x) + EVDEV_LONG_BITS - 1) / EVDEV_LONG_BITS)
+
+namespace ui {
+
+class EventDeviceInfo {

[rjkroege, 2013/11/04 23:39:46]

a class doc?

[spang, 2013/11/05 00:10:02]

Done.

+ public:
+  EventDeviceInfo();
+  ~EventDeviceInfo();
+
+  // Initialize device information from an open device.
+  bool Initialize(int fd);
+
+  // Check events this device can generate.
+  bool HasEventType(unsigned int type) const;
+  bool HasKeyEvent(unsigned int code) const;
+  bool HasRelEvent(unsigned int code) const;
+  bool HasAbsEvent(unsigned int code) const;
+  bool HasMscEvent(unsigned int code) const;
+  bool HasSwEvent(unsigned int code) const;
+  bool hasLedEvent(unsigned int code) const;
+
+  // Check input device properties.
+  bool HasProp(unsigned int code) const;
+
+ private:
+  unsigned long ev_bits_[EVDEV_BITS_TO_LONGS(EV_CNT)];

[rjkroege, 2013/11/04 23:39:46]

how big are these?

[spang, 2013/11/05 00:10:02]

Whole thing is currently 152 bytes.

This is less than X does though (it has the same and more). It also keeps it
around forever, which we are not (yet).

+  unsigned long key_bits_[EVDEV_BITS_TO_LONGS(KEY_CNT)];
+  unsigned long rel_bits_[EVDEV_BITS_TO_LONGS(REL_CNT)];
+  unsigned long abs_bits_[EVDEV_BITS_TO_LONGS(ABS_CNT)];
+  unsigned long msc_bits_[EVDEV_BITS_TO_LONGS(MSC_CNT)];
+  unsigned long sw_bits_[EVDEV_BITS_TO_LONGS(SW_CNT)];
+  unsigned long led_bits_[EVDEV_BITS_TO_LONGS(LED_CNT)];
+  unsigned long prop_bits_[EVDEV_BITS_TO_LONGS(INPUT_PROP_CNT)];
+
+  DISALLOW_COPY_AND_ASSIGN(EventDeviceInfo);
+};
+
+}  // namspace ui
+
+#endif  // UI_EVENTS_OZONE_EVDEV_EVENT_DEVICE_INFO_H_