1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
2 //  This source code is licensed under both the GPLv2 (found in the
3 //  COPYING file in the root directory) and Apache 2.0 License
4 //  (found in the LICENSE.Apache file in the root directory).
5 
6 #pragma once
7 #include <cassert>
8 #include <unordered_map>
9 #include "port/port.h"
10 #include "rocksdb/file_checksum.h"
11 #include "rocksdb/status.h"
12 #include "util/crc32c.h"
13 #include "util/string_util.h"
14 
15 namespace ROCKSDB_NAMESPACE {
16 
17 // This is the class to generate the file checksum based on Crc32. It
18 // will be used as the default checksum method for SST file checksum
19 class FileChecksumGenCrc32c : public FileChecksumGenerator {
20  public:
FileChecksumGenCrc32c(const FileChecksumGenContext &)21   FileChecksumGenCrc32c(const FileChecksumGenContext& /*context*/) {
22     checksum_ = 0;
23   }
24 
Update(const char * data,size_t n)25   void Update(const char* data, size_t n) override {
26     checksum_ = crc32c::Extend(checksum_, data, n);
27   }
28 
Finalize()29   void Finalize() override { checksum_str_ = Uint32ToString(checksum_); }
30 
GetChecksum()31   std::string GetChecksum() const override { return checksum_str_; }
32 
Name()33   const char* Name() const override { return "FileChecksumCrc32c"; }
34 
35   // Convert a uint32_t type data into a 4 bytes string.
Uint32ToString(uint32_t v)36   static std::string Uint32ToString(uint32_t v) {
37     std::string s;
38     if (port::kLittleEndian) {
39       s.append(reinterpret_cast<char*>(&v), sizeof(v));
40     } else {
41       char buf[sizeof(v)];
42       buf[0] = v & 0xff;
43       buf[1] = (v >> 8) & 0xff;
44       buf[2] = (v >> 16) & 0xff;
45       buf[3] = (v >> 24) & 0xff;
46       s.append(buf, sizeof(v));
47     }
48     size_t i = 0, j = s.size() - 1;
49     while (i < j) {
50       char tmp = s[i];
51       s[i] = s[j];
52       s[j] = tmp;
53       ++i;
54       --j;
55     }
56     return s;
57   }
58 
59   // Convert a 4 bytes size string into a uint32_t type data.
StringToUint32(std::string s)60   static uint32_t StringToUint32(std::string s) {
61     assert(s.size() == sizeof(uint32_t));
62     size_t i = 0, j = s.size() - 1;
63     while (i < j) {
64       char tmp = s[i];
65       s[i] = s[j];
66       s[j] = tmp;
67       ++i;
68       --j;
69     }
70     uint32_t v = 0;
71     if (port::kLittleEndian) {
72       memcpy(&v, s.c_str(), sizeof(uint32_t));
73     } else {
74       const char* buf = s.c_str();
75       v |= static_cast<uint32_t>(buf[0]);
76       v |= (static_cast<uint32_t>(buf[1]) << 8);
77       v |= (static_cast<uint32_t>(buf[2]) << 16);
78       v |= (static_cast<uint32_t>(buf[3]) << 24);
79     }
80     return v;
81   }
82 
83  private:
84   uint32_t checksum_;
85   std::string checksum_str_;
86 };
87 
88 class FileChecksumGenCrc32cFactory : public FileChecksumGenFactory {
89  public:
CreateFileChecksumGenerator(const FileChecksumGenContext & context)90   std::unique_ptr<FileChecksumGenerator> CreateFileChecksumGenerator(
91       const FileChecksumGenContext& context) override {
92     return std::unique_ptr<FileChecksumGenerator>(
93         new FileChecksumGenCrc32c(context));
94   }
95 
Name()96   const char* Name() const override { return "FileChecksumGenCrc32cFactory"; }
97 };
98 
99 // The default implementaion of FileChecksumList
100 class FileChecksumListImpl : public FileChecksumList {
101  public:
FileChecksumListImpl()102   FileChecksumListImpl() {}
103   void reset() override;
104 
105   size_t size() const override;
106 
107   Status GetAllFileChecksums(
108       std::vector<uint64_t>* file_numbers, std::vector<std::string>* checksums,
109       std::vector<std::string>* checksum_func_names) override;
110 
111   Status SearchOneFileChecksum(uint64_t file_number, std::string* checksum,
112                                std::string* checksum_func_name) override;
113 
114   Status InsertOneFileChecksum(uint64_t file_number,
115                                const std::string& checksum,
116                                const std::string& checksum_func_name) override;
117 
118   Status RemoveOneFileChecksum(uint64_t file_number) override;
119 
120  private:
121   // Key is the file number, the first portion of the value is checksum, the
122   // second portion of the value is checksum function name.
123   std::unordered_map<uint64_t, std::pair<std::string, std::string>>
124       checksum_map_;
125 };
126 
127 }  // namespace ROCKSDB_NAMESPACE
128