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 IDMAP_H_ 18 #define IDMAP_H_ 19 20 #include <memory> 21 #include <string> 22 #include <unordered_map> 23 24 #include "android-base/macros.h" 25 26 #include "androidfw/StringPiece.h" 27 28 namespace android { 29 30 struct Idmap_header; 31 struct IdmapEntry_header; 32 33 // Represents a loaded/parsed IDMAP for a Runtime Resource Overlay (RRO). 34 // An RRO and its target APK have different resource IDs assigned to their resources. Overlaying 35 // a resource is done by resource name. An IDMAP is a generated mapping between the resource IDs 36 // of the RRO and the target APK for each resource with the same name. 37 // A LoadedIdmap can be set alongside the overlay's LoadedArsc to allow the overlay ApkAssets to 38 // masquerade as the target ApkAssets resources. 39 class LoadedIdmap { 40 public: 41 // Loads an IDMAP from a chunk of memory. Returns nullptr if the IDMAP data was malformed. 42 static std::unique_ptr<const LoadedIdmap> Load(const StringPiece& idmap_data); 43 44 // Performs a lookup of the expected entry ID for the given IDMAP entry header. 45 // Returns true if the mapping exists and fills `output_entry_id` with the result. 46 static bool Lookup(const IdmapEntry_header* header, uint16_t input_entry_id, 47 uint16_t* output_entry_id); 48 49 // Returns the package ID for which this overlay should apply. 50 uint8_t TargetPackageId() const; 51 52 // Returns the path to the RRO (Runtime Resource Overlay) APK for which this IDMAP was generated. 53 inline const std::string& OverlayApkPath() const { 54 return overlay_apk_path_; 55 } 56 57 // Returns the mapping of target entry ID to overlay entry ID for the given target type. 58 const IdmapEntry_header* GetEntryMapForType(uint8_t type_id) const; 59 60 protected: 61 // Exposed as protected so that tests can subclass and mock this class out. 62 LoadedIdmap() = default; 63 64 const Idmap_header* header_ = nullptr; 65 std::string overlay_apk_path_; 66 std::unordered_map<uint8_t, const IdmapEntry_header*> type_map_; 67 68 private: 69 DISALLOW_COPY_AND_ASSIGN(LoadedIdmap); 70 71 explicit LoadedIdmap(const Idmap_header* header); 72 }; 73 74 } // namespace android 75 76 #endif // IDMAP_H_ 77
