1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
#include "serialise.hh"
#include "util.hh"
#include <cstring>
#include <cerrno>
#include <memory>
namespace nix {
void BufferedSink::operator () (const unsigned char * data, size_t len)
{
if (!buffer) buffer = decltype(buffer)(new unsigned char[bufSize]);
while (len) {
/* Optimisation: bypass the buffer if the data exceeds the
buffer size. */
if (bufPos + len >= bufSize) {
flush();
write(data, len);
break;
}
/* Otherwise, copy the bytes to the buffer. Flush the buffer
when it's full. */
size_t n = bufPos + len > bufSize ? bufSize - bufPos : len;
memcpy(buffer.get() + bufPos, data, n);
data += n; bufPos += n; len -= n;
if (bufPos == bufSize) flush();
}
}
void BufferedSink::flush()
{
if (bufPos == 0) return;
size_t n = bufPos;
bufPos = 0; // don't trigger the assert() in ~BufferedSink()
write(buffer.get(), n);
}
FdSink::~FdSink()
{
try { flush(); } catch (...) { ignoreException(); }
}
size_t threshold = 256 * 1024 * 1024;
static void warnLargeDump()
{
printError("warning: dumping very large path (> 256 MiB); this may run out of memory");
}
void FdSink::write(const unsigned char * data, size_t len)
{
written += len;
static bool warned = false;
if (warn && !warned) {
if (written > threshold) {
warnLargeDump();
warned = true;
}
}
try {
writeFull(fd, data, len);
} catch (SysError & e) {
_good = true;
}
}
bool FdSink::good()
{
return _good;
}
void Source::operator () (unsigned char * data, size_t len)
{
while (len) {
size_t n = read(data, len);
data += n; len -= n;
}
}
size_t BufferedSource::read(unsigned char * data, size_t len)
{
if (!buffer) buffer = decltype(buffer)(new unsigned char[bufSize]);
if (!bufPosIn) bufPosIn = readUnbuffered(buffer.get(), bufSize);
/* Copy out the data in the buffer. */
size_t n = len > bufPosIn - bufPosOut ? bufPosIn - bufPosOut : len;
memcpy(data, buffer.get() + bufPosOut, n);
bufPosOut += n;
if (bufPosIn == bufPosOut) bufPosIn = bufPosOut = 0;
return n;
}
bool BufferedSource::hasData()
{
return bufPosOut < bufPosIn;
}
size_t FdSource::readUnbuffered(unsigned char * data, size_t len)
{
ssize_t n;
do {
checkInterrupt();
n = ::read(fd, (char *) data, bufSize);
} while (n == -1 && errno == EINTR);
if (n == -1) { _good = false; throw SysError("reading from file"); }
if (n == 0) { _good = false; throw EndOfFile("unexpected end-of-file"); }
read += n;
return n;
}
bool FdSource::good()
{
return _good;
}
size_t StringSource::read(unsigned char * data, size_t len)
{
if (pos == s.size()) throw EndOfFile("end of string reached");
size_t n = s.copy((char *) data, len, pos);
pos += n;
return n;
}
void writePadding(size_t len, Sink & sink)
{
if (len % 8) {
unsigned char zero[8];
memset(zero, 0, sizeof(zero));
sink(zero, 8 - (len % 8));
}
}
void writeString(const unsigned char * buf, size_t len, Sink & sink)
{
sink << len;
sink(buf, len);
writePadding(len, sink);
}
Sink & operator << (Sink & sink, const string & s)
{
writeString((const unsigned char *) s.data(), s.size(), sink);
return sink;
}
template<class T> void writeStrings(const T & ss, Sink & sink)
{
sink << ss.size();
for (auto & i : ss)
sink << i;
}
Sink & operator << (Sink & sink, const Strings & s)
{
writeStrings(s, sink);
return sink;
}
Sink & operator << (Sink & sink, const StringSet & s)
{
writeStrings(s, sink);
return sink;
}
void readPadding(size_t len, Source & source)
{
if (len % 8) {
unsigned char zero[8];
size_t n = 8 - (len % 8);
source(zero, n);
for (unsigned int i = 0; i < n; i++)
if (zero[i]) throw SerialisationError("non-zero padding");
}
}
size_t readString(unsigned char * buf, size_t max, Source & source)
{
auto len = readNum<size_t>(source);
if (len > max) throw Error("string is too long");
source(buf, len);
readPadding(len, source);
return len;
}
string readString(Source & source)
{
auto len = readNum<size_t>(source);
auto buf = std::make_unique<unsigned char[]>(len);
source(buf.get(), len);
readPadding(len, source);
return string((char *) buf.get(), len);
}
Source & operator >> (Source & in, string & s)
{
s = readString(in);
return in;
}
template<class T> T readStrings(Source & source)
{
auto count = readNum<size_t>(source);
T ss;
while (count--)
ss.insert(ss.end(), readString(source));
return ss;
}
template Paths readStrings(Source & source);
template PathSet readStrings(Source & source);
void StringSink::operator () (const unsigned char * data, size_t len)
{
static bool warned = false;
if (!warned && s->size() > threshold) {
warnLargeDump();
warned = true;
}
s->append((const char *) data, len);
}
}
|
