1 // 2 // Copyright (C) 2020 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 UPDATE_ENGINE_PAYLOAD_GENERATOR_MERGE_SEQUENCE_GENERATOR_H_ 18 #define UPDATE_ENGINE_PAYLOAD_GENERATOR_MERGE_SEQUENCE_GENERATOR_H_ 19 20 #include <map> 21 #include <memory> 22 #include <set> 23 #include <utility> 24 #include <vector> 25 26 #include "update_engine/payload_generator/annotated_operation.h" 27 #include "update_engine/payload_generator/extent_ranges.h" 28 #include "update_engine/payload_generator/extent_utils.h" 29 #include "update_engine/update_metadata.pb.h" 30 31 namespace chromeos_update_engine { 32 // Constructs CowMergeOperation from src & dst extents 33 CowMergeOperation CreateCowMergeOperation(const Extent& src_extent, 34 const Extent& dst_extent); 35 36 // Comparator for CowMergeOperation. 37 bool operator<(const CowMergeOperation& op1, const CowMergeOperation& op2); 38 bool operator==(const CowMergeOperation& op1, const CowMergeOperation& op2); 39 40 std::ostream& operator<<(std::ostream& os, 41 const CowMergeOperation& merge_operation); 42 43 // This class takes a list of CowMergeOperations; and sorts them so that no 44 // read after write will happen by following the sequence. When there is a 45 // cycle, we will omit some operations in the list. Therefore, the result 46 // sequence may not contain all blocks in the input list. 47 class MergeSequenceGenerator { 48 public: 49 // Creates an object from a list of OTA InstallOperations. Returns nullptr on 50 // failure. 51 static std::unique_ptr<MergeSequenceGenerator> Create( 52 const std::vector<AnnotatedOperation>& aops); 53 // Checks that no read after write happens in the given sequence. 54 static bool ValidateSequence(const std::vector<CowMergeOperation>& sequence); 55 56 // Generates a merge sequence from |operations_|, puts the result in 57 // |sequence|. Returns false on failure. 58 bool Generate(std::vector<CowMergeOperation>* sequence) const; 59 60 private: 61 friend class MergeSequenceGeneratorTest; MergeSequenceGenerator(std::vector<CowMergeOperation> transfers)62 explicit MergeSequenceGenerator(std::vector<CowMergeOperation> transfers) 63 : operations_(std::move(transfers)) {} 64 65 // For a given merge operation, finds all the operations that should merge 66 // after myself. Put the result in |merge_after|. 67 bool FindDependency(std::map<CowMergeOperation, std::set<CowMergeOperation>>* 68 merge_after) const; 69 // The list of CowMergeOperations to sort. 70 std::vector<CowMergeOperation> operations_; 71 }; 72 73 void SplitSelfOverlapping(const Extent& src_extent, 74 const Extent& dst_extent, 75 std::vector<CowMergeOperation>* sequence); 76 77 } // namespace chromeos_update_engine 78 #endif 79