1 /* 2 * Copyright (C) 2017 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 #ifndef AAPT2_FILTER_H 18 #define AAPT2_FILTER_H 19 20 #include <string> 21 #include <string_view> 22 #include <vector> 23 24 #include "util/Util.h" 25 26 namespace aapt { 27 28 /** A filter to be applied to a path segment. */ 29 class IPathFilter { 30 public: 31 virtual ~IPathFilter() = default; 32 33 /** Returns true if the path should be kept. */ 34 virtual bool Keep(std::string_view path) = 0; 35 }; 36 37 /** 38 * Path filter that keeps anything that matches the provided prefix. 39 */ 40 class PrefixFilter : public IPathFilter { 41 public: PrefixFilter(std::string prefix)42 explicit PrefixFilter(std::string prefix) : prefix_(std::move(prefix)) { 43 } 44 45 /** Returns true if the provided path matches the prefix. */ Keep(std::string_view path)46 bool Keep(std::string_view path) override { 47 return util::StartsWith(path, prefix_); 48 } 49 50 private: 51 const std::string prefix_; 52 }; 53 54 /** Applies a set of IPathFilters to a path and returns true iif all filters keep the path. */ 55 class FilterChain : public IPathFilter { 56 public: 57 /** Adds a filter to the list to be applied to each path. */ AddFilter(std::unique_ptr<IPathFilter> filter)58 void AddFilter(std::unique_ptr<IPathFilter> filter) { 59 filters_.push_back(std::move(filter)); 60 } 61 62 /** Returns true if all filters keep the path. */ Keep(std::string_view path)63 bool Keep(std::string_view path) override { 64 for (auto& filter : filters_) { 65 if (!filter->Keep(path)) { 66 return false; 67 } 68 } 69 return true; 70 } 71 72 private: 73 std::vector<std::unique_ptr<IPathFilter>> filters_; 74 }; 75 76 } // namespace aapt 77 78 #endif // AAPT2_FILTER_H 79