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 "update_engine/payload_consumer/payload_constants.h"
24 #include "update_engine/update_metadata.pb.h"
25
26 // Utility functions for manipulating Extents and lists of blocks.
27
28 namespace chromeos_update_engine {
29
30 // |block| must either be the next block in the last extent or a block
31 // in the next extent. This function will not handle inserting block
32 // into an arbitrary place in the extents.
33 void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block);
34
35 // Get/SetElement are intentionally overloaded so that templated functions
36 // can accept either type of collection of Extents.
37 Extent GetElement(const std::vector<Extent>& collection, size_t index);
38 Extent GetElement(
39 const google::protobuf::RepeatedPtrField<Extent>& collection,
40 size_t index);
41
42 // Return the total number of blocks in a collection (vector or
43 // RepeatedPtrField) of Extents.
44 template<typename T>
BlocksInExtents(const T & collection)45 uint64_t BlocksInExtents(const T& collection) {
46 uint64_t ret = 0;
47 for (size_t i = 0; i < static_cast<size_t>(collection.size()); ++i) {
48 ret += GetElement(collection, i).num_blocks();
49 }
50 return ret;
51 }
52
53 // Takes a collection (vector or RepeatedPtrField) of Extent and
54 // returns a vector of the blocks referenced, in order.
55 template<typename T>
ExpandExtents(const T & extents)56 std::vector<uint64_t> ExpandExtents(const T& extents) {
57 std::vector<uint64_t> ret;
58 for (size_t i = 0, e = static_cast<size_t>(extents.size()); i != e; ++i) {
59 const Extent extent = GetElement(extents, i);
60 if (extent.start_block() == kSparseHole) {
61 ret.resize(ret.size() + extent.num_blocks(), kSparseHole);
62 } else {
63 for (uint64_t block = extent.start_block();
64 block < (extent.start_block() + extent.num_blocks()); block++) {
65 ret.push_back(block);
66 }
67 }
68 }
69 return ret;
70 }
71
72 // Stores all Extents in 'extents' into 'out'.
73 void StoreExtents(const std::vector<Extent>& extents,
74 google::protobuf::RepeatedPtrField<Extent>* out);
75
76 // Stores all extents in |extents| into |out_vector|.
77 void ExtentsToVector(const google::protobuf::RepeatedPtrField<Extent>& extents,
78 std::vector<Extent>* out_vector);
79
80 // Returns a string representing all extents in |extents|.
81 std::string ExtentsToString(const std::vector<Extent>& extents);
82
83 // Takes a pointer to extents |extents| and extents |extents_to_add|, and
84 // merges them by adding |extents_to_add| to |extents| and normalizing.
85 void ExtendExtents(
86 google::protobuf::RepeatedPtrField<Extent>* extents,
87 const google::protobuf::RepeatedPtrField<Extent>& extents_to_add);
88
89 // Takes a vector of extents and normalizes those extents. Expects the extents
90 // to be sorted by start block. E.g. if |extents| is [(1, 2), (3, 5), (10, 2)]
91 // then |extents| will be changed to [(1, 7), (10, 2)].
92 void NormalizeExtents(std::vector<Extent>* extents);
93
94 // Return a subsequence of the list of blocks passed. Both the passed list of
95 // blocks |extents| and the return value are expressed as a list of Extent, not
96 // blocks. The returned list skips the first |block_offset| blocks from the
97 // |extents| and cotains |block_count| blocks (or less if |extents| is shorter).
98 std::vector<Extent> ExtentsSublist(const std::vector<Extent>& extents,
99 uint64_t block_offset, uint64_t block_count);
100
101 bool operator==(const Extent& a, const Extent& b);
102
103 } // namespace chromeos_update_engine
104
105 #endif // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
106