1 /* 2 * Copyright (C) 2010 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 <android-base/result.h> 20 #include <utils/Tokenizer.h> 21 22 #include <optional> 23 #include <string> 24 #include <unordered_map> 25 #include <unordered_set> 26 27 namespace android { 28 29 /* 30 * Provides a mechanism for passing around string-based property key / value pairs 31 * and loading them from property files. 32 * 33 * The property files have the following simple structure: 34 * 35 * # Comment 36 * key = value 37 * 38 * Keys and values are any sequence of printable ASCII characters. 39 * The '=' separates the key from the value. 40 * The key and value may not contain whitespace. 41 * 42 * The '\' character is reserved for escape sequences and is not currently supported. 43 * The '"" character is reserved for quoting and is not currently supported. 44 * Files that contain the '\' or '"' character will fail to parse. 45 * 46 * The file must not contain duplicate keys. 47 * 48 * TODO Support escape sequences and quoted values when needed. 49 */ 50 class PropertyMap { 51 public: 52 /* Creates an empty property map. */ 53 PropertyMap(); 54 ~PropertyMap(); 55 56 /* Clears the property map. */ 57 void clear(); 58 59 /* Adds a property. 60 * Replaces the property with the same key if it is already present. 61 */ 62 void addProperty(const std::string& key, const std::string& value); 63 64 /* Returns a set of all property keys starting with the given prefix. */ 65 std::unordered_set<std::string> getKeysWithPrefix(const std::string& prefix) const; 66 67 /* Gets the value of a property and parses it. Returns nullopt if the key wasn't found or 68 * couldn't be parsed as the requested type. (Warnings are also logged in the case of parsing 69 * failures.) 70 */ 71 std::optional<std::string> getString(const std::string& key) const; 72 std::optional<bool> getBool(const std::string& key) const; 73 std::optional<int32_t> getInt(const std::string& key) const; 74 std::optional<float> getFloat(const std::string& key) const; 75 std::optional<double> getDouble(const std::string& key) const; 76 77 /* Adds all values from the specified property map. */ 78 void addAll(const PropertyMap* map); 79 80 /* Loads a property map from a file. */ 81 static android::base::Result<std::unique_ptr<PropertyMap>> load(const char* filename); 82 83 private: 84 /* Returns true if the property map contains the specified key. */ 85 bool hasProperty(const std::string& key) const; 86 87 class Parser { 88 PropertyMap* mMap; 89 Tokenizer* mTokenizer; 90 91 public: 92 Parser(PropertyMap* map, Tokenizer* tokenizer); 93 ~Parser(); 94 status_t parse(); 95 96 private: 97 status_t parseType(); 98 status_t parseKey(); 99 status_t parseKeyProperty(); 100 status_t parseModifier(const std::string& token, int32_t* outMetaState); 101 status_t parseCharacterLiteral(char16_t* outCharacter); 102 }; 103 104 std::unordered_map<std::string, std::string> mProperties; 105 }; 106 107 } // namespace android 108