ui/events/devices/device_util_linux.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/events/devices/device_util_linux.h"
   6
   7 #include <string>
   8
   9 #include "base/files/file_enumerator.h"
  10 #include "base/files/file_path.h"
  11 #include "base/message_loop/message_loop.h"
  12 #include "base/strings/string_util.h"
  13
  14 namespace ui {
  15
  16 // We consider the touchscreen to be internal if it is an I2c device. We search
  17 // all the dev input nodes registered by I2C devices to see if we can find
  18 // eventXXX.
  19 bool IsTouchscreenInternal(const base::FilePath& path) {
  20   DCHECK(!base::MessageLoopForUI::IsCurrent());
  21   std::string event_node = path.BaseName().value();
  22   if (event_node.empty() || !StartsWithASCII(event_node, "event", false))
  23     return false;
  24
  25   // Extract id "XXX" from "eventXXX"
  26   std::string event_node_id = event_node.substr(5);
  27
  28   // I2C input device registers its dev input node at
  29   // /sys/bus/i2c/devices/*/input/inputXXX/eventXXX
  30   base::FileEnumerator i2c_enum(
  31       base::FilePath(FILE_PATH_LITERAL("/sys/bus/i2c/devices/")),
  32       false,
  33       base::FileEnumerator::DIRECTORIES);
  34   for (base::FilePath i2c_name = i2c_enum.Next(); !i2c_name.empty();
  35        i2c_name = i2c_enum.Next()) {
  36     base::FileEnumerator input_enum(
  37         i2c_name.Append(FILE_PATH_LITERAL("input")),
  38         false,
  39         base::FileEnumerator::DIRECTORIES,
  40         FILE_PATH_LITERAL("input*"));
  41     for (base::FilePath input = input_enum.Next(); !input.empty();
  42          input = input_enum.Next()) {
  43       if (input.BaseName().value().substr(5) == event_node_id)
  44         return true;
  45     }
  46   }
  47
  48   return false;
  49 }
  50
  51 }  // namespace