1 //
2 // Copyright (C) 2009 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_CONSUMER_EXTENT_WRITER_H_
18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_WRITER_H_
19 
20 #include <memory>
21 #include <utility>
22 
23 #include <base/logging.h>
24 #include <brillo/secure_blob.h>
25 
26 #include "update_engine/common/utils.h"
27 #include "update_engine/payload_consumer/file_descriptor.h"
28 #include "update_engine/update_metadata.pb.h"
29 
30 // ExtentWriter is an abstract class which synchronously writes to a given
31 // file descriptor at the extents given.
32 
33 namespace chromeos_update_engine {
34 
35 class ExtentWriter {
36  public:
37   ExtentWriter() = default;
38   virtual ~ExtentWriter() = default;
39 
40   // Returns true on success.
41   virtual bool Init(FileDescriptorPtr fd,
42                     const google::protobuf::RepeatedPtrField<Extent>& extents,
43                     uint32_t block_size) = 0;
44 
45   // Returns true on success.
46   virtual bool Write(const void* bytes, size_t count) = 0;
47 };
48 
49 // DirectExtentWriter is probably the simplest ExtentWriter implementation.
50 // It writes the data directly into the extents.
51 
52 class DirectExtentWriter : public ExtentWriter {
53  public:
54   DirectExtentWriter() = default;
55   ~DirectExtentWriter() override = default;
56 
Init(FileDescriptorPtr fd,const google::protobuf::RepeatedPtrField<Extent> & extents,uint32_t block_size)57   bool Init(FileDescriptorPtr fd,
58             const google::protobuf::RepeatedPtrField<Extent>& extents,
59             uint32_t block_size) override {
60     fd_ = fd;
61     block_size_ = block_size;
62     extents_ = extents;
63     cur_extent_ = extents_.begin();
64     return true;
65   }
66   bool Write(const void* bytes, size_t count) override;
67 
68  private:
69   FileDescriptorPtr fd_{nullptr};
70 
71   size_t block_size_{0};
72   // Bytes written into |cur_extent_| thus far.
73   uint64_t extent_bytes_written_{0};
74   google::protobuf::RepeatedPtrField<Extent> extents_;
75   // The next call to write should correspond to |cur_extents_|.
76   google::protobuf::RepeatedPtrField<Extent>::iterator cur_extent_;
77 };
78 
79 }  // namespace chromeos_update_engine
80 
81 #endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_EXTENT_WRITER_H_
82