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 UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
18 #define UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
19
20 #include <string>
21 #include <vector>
22
23 #include <base/logging.h>
24
25 #include "update_engine/payload_consumer/payload_constants.h"
26 #include "update_engine/update_metadata.pb.h"
27
28 // Utility functions for manipulating Extents and lists of blocks.
29
30 namespace chromeos_update_engine {
31
32 // |block| must either be the next block in the last extent or a block
33 // in the next extent. This function will not handle inserting block
34 // into an arbitrary place in the extents.
35 void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block);
36
37 // Takes a collection (vector or RepeatedPtrField) of Extent and
38 // returns a vector of the blocks referenced, in order.
39 template <typename T>
ExpandExtents(const T & extents)40 std::vector<uint64_t> ExpandExtents(const T& extents) {
41 std::vector<uint64_t> ret;
42 for (const auto& extent : extents) {
43 if (extent.start_block() == kSparseHole) {
44 ret.resize(ret.size() + extent.num_blocks(), kSparseHole);
45 } else {
46 for (uint64_t block = extent.start_block();
47 block < (extent.start_block() + extent.num_blocks());
48 block++) {
49 ret.push_back(block);
50 }
51 }
52 }
53 return ret;
54 }
55
56 // Stores all Extents in 'extents' into 'out'.
57 void StoreExtents(const std::vector<Extent>& extents,
58 google::protobuf::RepeatedPtrField<Extent>* out);
59
60 // Stores all extents in |extents| into |out_vector|.
61 void ExtentsToVector(const google::protobuf::RepeatedPtrField<Extent>& extents,
62 std::vector<Extent>* out_vector);
63
64 // Returns a string representing all extents in |extents|.
65 std::string ExtentsToString(const std::vector<Extent>& extents);
66
67 // Takes a pointer to extents |extents| and extents |extents_to_add|, and
68 // merges them by adding |extents_to_add| to |extents| and normalizing.
69 void ExtendExtents(
70 google::protobuf::RepeatedPtrField<Extent>* extents,
71 const google::protobuf::RepeatedPtrField<Extent>& extents_to_add);
72
73 // Takes a vector of extents and normalizes those extents. Expects the extents
74 // to be sorted by start block. E.g. if |extents| is [(1, 2), (3, 5), (10, 2)]
75 // then |extents| will be changed to [(1, 7), (10, 2)].
76 void NormalizeExtents(std::vector<Extent>* extents);
77
78 // Return a subsequence of the list of blocks passed. Both the passed list of
79 // blocks |extents| and the return value are expressed as a list of Extent, not
80 // blocks. The returned list skips the first |block_offset| blocks from the
81 // |extents| and cotains |block_count| blocks (or less if |extents| is shorter).
82 std::vector<Extent> ExtentsSublist(const std::vector<Extent>& extents,
83 uint64_t block_offset,
84 uint64_t block_count);
85
86 bool operator==(const Extent& a, const Extent& b);
87
88 // TODO(zhangkelvin) This is ugly. Rewrite using C++20's coroutine once
89 // that's available. Unfortunately with C++17 this is the best I could do.
90
91 // An iterator that takes a sequence of extents, and iterate over blocks
92 // inside this sequence of extents.
93 // Example usage:
94
95 // BlockIterator it1{src_extents};
96 // while(!it1.is_end()) {
97 // auto block = *it1;
98 // Do stuff with |block|
99 // }
100 struct BlockIterator {
BlockIteratorBlockIterator101 explicit BlockIterator(
102 const google::protobuf::RepeatedPtrField<Extent>& src_extents)
103 : src_extents_(src_extents) {}
104
105 BlockIterator& operator++() {
106 CHECK_LT(cur_extent_, src_extents_.size());
107 block_offset_++;
108 if (block_offset_ >= src_extents_[cur_extent_].num_blocks()) {
109 cur_extent_++;
110 block_offset_ = 0;
111 }
112 return *this;
113 }
114
is_endBlockIterator115 [[nodiscard]] bool is_end() { return cur_extent_ >= src_extents_.size(); }
116 [[nodiscard]] uint64_t operator*() {
117 return src_extents_[cur_extent_].start_block() + block_offset_;
118 }
119
120 const google::protobuf::RepeatedPtrField<Extent>& src_extents_;
121 int cur_extent_ = 0;
122 size_t block_offset_ = 0;
123 };
124
125 std::ostream& operator<<(std::ostream& out, const Extent& extent);
126
127 } // namespace chromeos_update_engine
128
129 #endif // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
130