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_CONSUMER_XZ_EXTENT_WRITER_H_
18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_XZ_EXTENT_WRITER_H_
19 
20 #include <xz.h>
21 
22 #include <memory>
23 #include <utility>
24 
25 #include <brillo/secure_blob.h>
26 
27 #include "update_engine/payload_consumer/extent_writer.h"
28 
29 // XzExtentWriter is a concrete ExtentWriter subclass that xz-decompresses
30 // what it's given in Write using xz-embedded. Note that xz-embedded only
31 // supports files with either no CRC or CRC-32. It passes the decompressed data
32 // to an underlying ExtentWriter.
33 
34 namespace chromeos_update_engine {
35 
36 class XzExtentWriter : public ExtentWriter {
37   struct xz_deleter {
operatorxz_deleter38     constexpr void operator()(xz_dec* p) { xz_dec_end(p); }
39   };
40 
41  public:
XzExtentWriter(std::unique_ptr<ExtentWriter> underlying_writer)42   explicit XzExtentWriter(std::unique_ptr<ExtentWriter> underlying_writer)
43       : underlying_writer_(std::move(underlying_writer)) {}
44   ~XzExtentWriter() override;
45 
46   bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
47             uint32_t block_size) override;
48   bool Write(const void* bytes, size_t count) override;
49 
50  private:
51   // The underlying ExtentWriter.
52   std::unique_ptr<ExtentWriter> underlying_writer_;
53   // The opaque xz decompressor struct.
54   std::unique_ptr<xz_dec, xz_deleter> stream_{nullptr};
55   brillo::Blob input_buffer_;
56 
57   DISALLOW_COPY_AND_ASSIGN(XzExtentWriter);
58 };
59 
60 }  // namespace chromeos_update_engine
61 
62 #endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_XZ_EXTENT_WRITER_H_
63