1 /* 2 * Copyright (C) 2015 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 TOOLS_AAPT2_FORMAT_BINARY_TABLEFLATTENER_H_ 18 #define TOOLS_AAPT2_FORMAT_BINARY_TABLEFLATTENER_H_ 19 20 #include <map> 21 #include <set> 22 #include <string> 23 #include <unordered_map> 24 25 #include "Resource.h" 26 #include "ResourceTable.h" 27 #include "android-base/macros.h" 28 #include "androidfw/BigBuffer.h" 29 #include "process/IResourceTableConsumer.h" 30 31 namespace aapt { 32 33 // The percentage of used entries for a type for which using a sparse encoding is 34 // preferred. 35 constexpr const size_t kSparseEncodingThreshold = 60; 36 37 enum class SparseEntriesMode { 38 // Disables sparse encoding for entries. 39 Disabled, 40 // Enables sparse encoding for all entries for APKs with O+ minSdk. For APKs with minSdk less 41 // than O only applies sparse encoding for resource configuration available on O+. 42 Enabled, 43 // Enables sparse encoding for all entries regardless of minSdk. 44 Forced, 45 }; 46 47 struct TableFlattenerOptions { 48 // When enabled, types for configurations with a sparse set of entries are encoded 49 // as a sparse map of entry ID and offset to actual data. 50 SparseEntriesMode sparse_entries = SparseEntriesMode::Disabled; 51 52 // When true, use compact entries for simple data 53 bool use_compact_entries = false; 54 55 // When true, the key string pool in the final ResTable 56 // is collapsed to a single entry. All resource entries 57 // have name indices that point to this single value 58 bool collapse_key_stringpool = false; 59 60 // Set of resources to avoid collapsing to a single entry in key stringpool. 61 std::set<ResourceName> name_collapse_exemptions; 62 63 // Set of resources to avoid path shortening. 64 std::set<ResourceName> path_shorten_exemptions; 65 66 // Map from original resource paths to shortened resource paths. 67 std::map<std::string, std::string> shortened_path_map; 68 69 // When enabled, only unique pairs of entry and value are stored in type chunks. 70 // 71 // By default, all such pairs are unique because a reference to resource name in the string pool 72 // is a part of the pair. But when resource names are collapsed (using 'collapse_key_stringpool' 73 // flag or manually) the same data might be duplicated multiple times in the same type chunk. 74 // 75 // For example: an application has 3 boolean resources with collapsed names and 3 'true' values 76 // are defined for these resources in 'default' configuration. All pairs of entry and value for 77 // these resources will have the same binary representation and stored only once in type chunk 78 // instead of three times when this flag is disabled. 79 // 80 // This applies only to simple entries (entry->flags & ResTable_entry::FLAG_COMPLEX == 0). 81 bool deduplicate_entry_values = false; 82 83 // Map from original resource ids to obfuscated names. 84 std::unordered_map<uint32_t, std::string> id_resource_map; 85 }; 86 87 class TableFlattener : public IResourceTableConsumer { 88 public: TableFlattener(const TableFlattenerOptions & options,android::BigBuffer * buffer)89 explicit TableFlattener(const TableFlattenerOptions& options, android::BigBuffer* buffer) 90 : options_(options), buffer_(buffer) { 91 } 92 93 bool Consume(IAaptContext* context, ResourceTable* table) override; 94 95 private: 96 TableFlattenerOptions options_; 97 android::BigBuffer* buffer_; 98 99 DISALLOW_COPY_AND_ASSIGN(TableFlattener); 100 }; 101 102 } // namespace aapt 103 104 #endif // TOOLS_AAPT2_FORMAT_BINARY_TABLEFLATTENER_H_ 105