Fairphone ODM | 25c12f5 | 2023-12-15 17:24:06 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #pragma once |
| 18 | |
| 19 | #include <sys/cdefs.h> |
| 20 | |
| 21 | #include <chrono> |
| 22 | #include <limits> |
| 23 | #include <optional> |
| 24 | #include <string> |
| 25 | |
| 26 | struct prop_info; |
| 27 | |
| 28 | namespace android { |
| 29 | namespace base { |
| 30 | |
| 31 | // Returns the current value of the system property `key`, |
| 32 | // or `default_value` if the property is empty or doesn't exist. |
| 33 | std::string GetProperty(const std::string& key, const std::string& default_value); |
| 34 | |
| 35 | // Returns true if the system property `key` has the value "1", "y", "yes", "on", or "true", |
| 36 | // false for "0", "n", "no", "off", or "false", or `default_value` otherwise. |
| 37 | bool GetBoolProperty(const std::string& key, bool default_value); |
| 38 | |
| 39 | // Returns the signed integer corresponding to the system property `key`. |
| 40 | // If the property is empty, doesn't exist, doesn't have an integer value, or is outside |
| 41 | // the optional bounds, returns `default_value`. |
| 42 | template <typename T> T GetIntProperty(const std::string& key, |
| 43 | T default_value, |
| 44 | T min = std::numeric_limits<T>::min(), |
| 45 | T max = std::numeric_limits<T>::max()); |
| 46 | |
| 47 | // Returns the unsigned integer corresponding to the system property `key`. |
| 48 | // If the property is empty, doesn't exist, doesn't have an integer value, or is outside |
| 49 | // the optional bound, returns `default_value`. |
| 50 | template <typename T> T GetUintProperty(const std::string& key, |
| 51 | T default_value, |
| 52 | T max = std::numeric_limits<T>::max()); |
| 53 | |
| 54 | // Sets the system property `key` to `value`. |
| 55 | bool SetProperty(const std::string& key, const std::string& value); |
| 56 | |
| 57 | // Waits for the system property `key` to have the value `expected_value`. |
| 58 | // Times out after `relative_timeout`. |
| 59 | // Returns true on success, false on timeout. |
| 60 | #if defined(__BIONIC__) |
| 61 | bool WaitForProperty(const std::string& key, const std::string& expected_value, |
| 62 | std::chrono::milliseconds relative_timeout = std::chrono::milliseconds::max()); |
| 63 | #endif |
| 64 | |
| 65 | // Waits for the system property `key` to be created. |
| 66 | // Times out after `relative_timeout`. |
| 67 | // Returns true on success, false on timeout. |
| 68 | #if defined(__BIONIC__) |
| 69 | bool WaitForPropertyCreation(const std::string& key, std::chrono::milliseconds relative_timeout = |
| 70 | std::chrono::milliseconds::max()); |
| 71 | #endif |
| 72 | |
| 73 | #if defined(__BIONIC__) && __cplusplus >= 201703L |
| 74 | // Cached system property lookup. For code that needs to read the same property multiple times, |
| 75 | // this class helps optimize those lookups. |
| 76 | class CachedProperty { |
| 77 | public: |
| 78 | explicit CachedProperty(const char* property_name); |
| 79 | |
| 80 | // Returns the current value of the underlying system property as cheaply as possible. |
| 81 | // The returned pointer is valid until the next call to Get. Because most callers are going |
| 82 | // to want to parse the string returned here and cached that as well, this function performs |
| 83 | // no locking, and is completely thread unsafe. It is the caller's responsibility to provide a |
| 84 | // lock for thread-safety. |
| 85 | // |
| 86 | // Note: *changed can be set to true even if the contents of the property remain the same. |
| 87 | const char* Get(bool* changed = nullptr); |
| 88 | |
| 89 | private: |
| 90 | std::string property_name_; |
| 91 | const prop_info* prop_info_; |
| 92 | std::optional<uint32_t> cached_area_serial_; |
| 93 | std::optional<uint32_t> cached_property_serial_; |
| 94 | char cached_value_[92]; |
| 95 | bool is_read_only_; |
| 96 | const char* read_only_property_; |
| 97 | }; |
| 98 | #endif |
| 99 | |
| 100 | static inline int HwTimeoutMultiplier() { |
| 101 | return android::base::GetIntProperty("ro.hw_timeout_multiplier", 1); |
| 102 | } |
| 103 | |
| 104 | } // namespace base |
| 105 | } // namespace android |
| 106 | |
| 107 | #if !defined(__BIONIC__) |
| 108 | /** Implementation detail. */ |
| 109 | extern "C" int __system_property_set(const char*, const char*); |
| 110 | /** Implementation detail. */ |
| 111 | extern "C" int __system_property_get(const char*, char*); |
| 112 | #endif |