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1 // Copyright 2016 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 "device/generic_sensor/linux/platform_sensor_utils_linux.h" | |
6 | |
7 #include "base/files/file_enumerator.h" | |
8 #include "base/files/file_util.h" | |
9 #include "base/strings/string_number_conversions.h" | |
10 #include "base/strings/string_util.h" | |
11 #include "base/threading/thread_restrictions.h" | |
12 #include "device/generic_sensor/public/cpp/sensor_reading.h" | |
13 | |
14 namespace device { | |
15 | |
16 namespace { | |
17 | |
18 bool InitSensorPaths(const std::vector<std::string>& input_names, | |
19 const char* base_path, | |
20 std::vector<base::FilePath>* sensor_paths) { | |
21 // Search the iio/devices directory for a subdirectory (eg "device0" or | |
22 // "iio:device0") that contains the specified input_name file (eg | |
23 // "in_illuminance_input" or "in_illuminance0_input"). | |
24 base::FileEnumerator dir_enumerator(base::FilePath(base_path), false, | |
25 base::FileEnumerator::DIRECTORIES); | |
26 for (base::FilePath check_path = dir_enumerator.Next(); !check_path.empty(); | |
27 check_path = dir_enumerator.Next()) { | |
28 for (auto const& file_name : input_names) { | |
29 base::FilePath full_path = check_path.Append(file_name); | |
30 if (base::PathExists(full_path)) { | |
31 sensor_paths->push_back(full_path); | |
32 return true; | |
33 } | |
34 } | |
35 } | |
36 return false; | |
37 } | |
38 | |
39 bool GetSensorFilePaths(const SensorDataLinux& data, | |
40 std::vector<base::FilePath>* sensor_paths) { | |
41 DCHECK(sensor_paths->empty()); | |
42 // Depending on a sensor, there can be up to three sets of files that need | |
43 // to be checked. If one of three files is not found, a sensor is | |
44 // treated as a non-existing one. | |
45 for (auto const& file_names : data.sensor_file_names) { | |
46 // Supply InitSensorPaths() with a set of files. | |
47 // Only one file from each set should be found. | |
48 if (!InitSensorPaths(file_names, data.base_path_sensor_linux, sensor_paths)) | |
49 return false; | |
50 } | |
51 return true; | |
52 } | |
53 | |
54 // Returns -1 if unable to read a scaling value. | |
55 // Otherwise, returns a scaling value read from a file. | |
56 double ReadSensorScalingValue(const base::FilePath& scale_file_path) { | |
57 std::string value; | |
58 if (!base::ReadFileToString(scale_file_path, &value)) | |
59 return -1; | |
60 | |
61 double scaling_value; | |
62 base::TrimWhitespaceASCII(value, base::TRIM_ALL, &value); | |
63 if (!base::StringToDouble(value, &scaling_value)) | |
64 return -1; | |
65 return scaling_value; | |
66 } | |
67 | |
68 } // namespace | |
69 | |
70 // static | |
71 std::unique_ptr<SensorReader> SensorReader::Create( | |
72 const SensorDataLinux& data) { | |
73 base::ThreadRestrictions::AssertIOAllowed(); | |
74 std::vector<base::FilePath> sensor_paths; | |
75 if (!GetSensorFilePaths(data, &sensor_paths)) | |
76 return nullptr; | |
77 | |
78 DCHECK(!sensor_paths.empty()); | |
79 // Scaling value is 1 if scaling file is not specified is |data| or scaling | |
80 // file is not found. | |
81 double scaling_value = 1; | |
82 if (!data.sensor_scale_name.empty()) { | |
83 const base::FilePath scale_file_path = | |
84 sensor_paths.back().DirName().Append(data.sensor_scale_name); | |
85 if (base::PathExists(scale_file_path)) | |
86 scaling_value = ReadSensorScalingValue(scale_file_path); | |
87 } | |
88 | |
89 // A file with a scaling value is found, but couldn't be read. | |
90 if (scaling_value == -1) | |
91 return nullptr; | |
92 | |
93 return base::WrapUnique(new SensorReader( | |
94 std::move(sensor_paths), scaling_value, data.apply_scaling_func)); | |
95 } | |
96 | |
97 SensorReader::SensorReader( | |
98 std::vector<base::FilePath> sensor_paths, | |
99 double scaling_value, | |
100 const SensorDataLinux::ReaderFunctor& apply_scaling_func) | |
101 : sensor_paths_(std::move(sensor_paths)), | |
102 scaling_value_(scaling_value), | |
103 apply_scaling_func_(apply_scaling_func) { | |
104 DCHECK(!sensor_paths_.empty()); | |
105 } | |
106 | |
107 SensorReader::~SensorReader() = default; | |
108 | |
109 bool SensorReader::ReadSensorReading(SensorReading* reading) { | |
110 base::ThreadRestrictions::AssertIOAllowed(); | |
111 SensorReading readings; | |
112 DCHECK_LE(sensor_paths_.size(), arraysize(readings.values)); | |
113 int i = 0; | |
114 for (const auto& path : sensor_paths_) { | |
115 std::string new_read_value; | |
116 if (!base::ReadFileToString(path, &new_read_value)) | |
117 return false; | |
118 | |
119 double new_value = 0; | |
120 base::TrimWhitespaceASCII(new_read_value, base::TRIM_ALL, &new_read_value); | |
121 if (!base::StringToDouble(new_read_value, &new_value)) | |
122 return false; | |
123 readings.values[i++] = new_value; | |
124 } | |
125 if (!apply_scaling_func_.is_null()) | |
126 apply_scaling_func_.Run(scaling_value_, readings); | |
127 *reading = readings; | |
128 return true; | |
129 } | |
130 | |
131 } // namespace device | |
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