streams.cpp raw
1 // Copyright (c) 2009-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or https://opensource.org/license/mit/.
4
5 #include <memusage.h>
6 #include <span.h>
7 #include <streams.h>
8 #include <util/fs_helpers.h>
9 #include <util/obfuscation.h>
10
11 #include <array>
12
13 AutoFile::AutoFile(std::FILE* file, const Obfuscation& obfuscation) : m_file{file}, m_obfuscation{obfuscation}
14 {
15 if (!IsNull()) {
16 auto pos{std::ftell(m_file)};
17 if (pos >= 0) m_position = pos;
18 }
19 }
20
21 std::size_t AutoFile::detail_fread(std::span<std::byte> dst)
22 {
23 if (!m_file) throw std::ios_base::failure("AutoFile::read: file handle is nullptr");
24 const size_t ret = std::fread(dst.data(), 1, dst.size(), m_file);
25 if (m_obfuscation) {
26 if (!m_position) throw std::ios_base::failure("AutoFile::read: position unknown");
27 m_obfuscation(dst.subspan(0, ret), *m_position);
28 }
29 if (m_position) *m_position += ret;
30 return ret;
31 }
32
33 void AutoFile::seek(int64_t offset, int origin)
34 {
35 if (IsNull()) {
36 throw std::ios_base::failure("AutoFile::seek: file handle is nullptr");
37 }
38 if (std::fseek(m_file, offset, origin) != 0) {
39 throw std::ios_base::failure(feof() ? "AutoFile::seek: end of file" : "AutoFile::seek: fseek failed");
40 }
41 if (origin == SEEK_SET) {
42 m_position = offset;
43 } else if (origin == SEEK_CUR && m_position.has_value()) {
44 *m_position += offset;
45 } else {
46 int64_t r{std::ftell(m_file)};
47 if (r < 0) {
48 throw std::ios_base::failure("AutoFile::seek: ftell failed");
49 }
50 m_position = r;
51 }
52 }
53
54 int64_t AutoFile::tell()
55 {
56 if (!m_position.has_value()) throw std::ios_base::failure("AutoFile::tell: position unknown");
57 return *m_position;
58 }
59
60 int64_t AutoFile::size()
61 {
62 if (IsNull()) {
63 throw std::ios_base::failure("AutoFile::size: file handle is nullptr");
64 }
65 // Temporarily save the current position
66 int64_t current_pos = tell();
67 seek(0, SEEK_END);
68 int64_t file_size = tell();
69 // Restore the original position
70 seek(current_pos, SEEK_SET);
71 return file_size;
72 }
73
74 void AutoFile::read(std::span<std::byte> dst)
75 {
76 if (detail_fread(dst) != dst.size()) {
77 throw std::ios_base::failure(feof() ? "AutoFile::read: end of file" : "AutoFile::read: fread failed");
78 }
79 }
80
81 void AutoFile::ignore(size_t nSize)
82 {
83 if (!m_file) throw std::ios_base::failure("AutoFile::ignore: file handle is nullptr");
84 unsigned char data[4096];
85 while (nSize > 0) {
86 size_t nNow = std::min<size_t>(nSize, sizeof(data));
87 if (std::fread(data, 1, nNow, m_file) != nNow) {
88 throw std::ios_base::failure(feof() ? "AutoFile::ignore: end of file" : "AutoFile::ignore: fread failed");
89 }
90 nSize -= nNow;
91 if (m_position.has_value()) *m_position += nNow;
92 }
93 }
94
95 void AutoFile::write(std::span<const std::byte> src)
96 {
97 if (!m_file) throw std::ios_base::failure("AutoFile::write: file handle is nullptr");
98 if (!m_obfuscation) {
99 if (std::fwrite(src.data(), 1, src.size(), m_file) != src.size()) {
100 throw std::ios_base::failure("AutoFile::write: write failed");
101 }
102 m_was_written = true;
103 if (m_position.has_value()) *m_position += src.size();
104 } else {
105 std::array<std::byte, 4096> buf;
106 while (src.size()) {
107 auto buf_now{std::span{buf}.first(std::min<size_t>(src.size(), buf.size()))};
108 std::copy_n(src.begin(), buf_now.size(), buf_now.begin());
109 write_buffer(buf_now);
110 src = src.subspan(buf_now.size());
111 }
112 }
113 }
114
115 void AutoFile::write_buffer(std::span<std::byte> src)
116 {
117 if (!m_file) throw std::ios_base::failure("AutoFile::write_buffer: file handle is nullptr");
118 if (m_obfuscation) {
119 if (!m_position) throw std::ios_base::failure("AutoFile::write_buffer: obfuscation position unknown");
120 m_obfuscation(src, *m_position); // obfuscate in-place
121 }
122 if (std::fwrite(src.data(), 1, src.size(), m_file) != src.size()) {
123 throw std::ios_base::failure("AutoFile::write_buffer: write failed");
124 }
125 m_was_written = true;
126 if (m_position) *m_position += src.size();
127 }
128
129 bool AutoFile::Commit()
130 {
131 return ::FileCommit(m_file);
132 }
133
134 bool AutoFile::Truncate(unsigned size)
135 {
136 m_was_written = true;
137 return ::TruncateFile(m_file, size);
138 }
139
140 size_t DataStream::GetMemoryUsage() const noexcept
141 {
142 return sizeof(*this) + memusage::DynamicUsage(vch);
143 }
144