forked from lix-project/lix
d9e8ab0ff2
In some Boost versions, coroutines don't propagate exceptions properly, causing Nix to fail with the exception 'coroutine has finished'.
316 lines
6.6 KiB
C++
316 lines
6.6 KiB
C++
#include "serialise.hh"
|
|
#include "util.hh"
|
|
|
|
#include <cstring>
|
|
#include <cerrno>
|
|
#include <memory>
|
|
|
|
#include <boost/coroutine2/coroutine.hpp>
|
|
|
|
|
|
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 = false;
|
|
throw;
|
|
}
|
|
}
|
|
|
|
|
|
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;
|
|
}
|
|
}
|
|
|
|
|
|
std::string Source::drain()
|
|
{
|
|
std::string s;
|
|
std::vector<unsigned char> buf(8192);
|
|
while (true) {
|
|
size_t n;
|
|
try {
|
|
n = read(buf.data(), buf.size());
|
|
s.append((char *) buf.data(), n);
|
|
} catch (EndOfFile &) {
|
|
break;
|
|
}
|
|
}
|
|
return s;
|
|
}
|
|
|
|
|
|
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, len);
|
|
} 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;
|
|
}
|
|
|
|
|
|
#if BOOST_VERSION >= 106300 && BOOST_VERSION < 106600
|
|
#error Coroutines are broken in this version of Boost!
|
|
#endif
|
|
|
|
std::unique_ptr<Source> sinkToSource(std::function<void(Sink &)> fun)
|
|
{
|
|
struct SinkToSource : Source
|
|
{
|
|
typedef boost::coroutines2::coroutine<std::string> coro_t;
|
|
|
|
coro_t::pull_type coro;
|
|
|
|
SinkToSource(std::function<void(Sink &)> fun)
|
|
: coro([&](coro_t::push_type & yield) {
|
|
LambdaSink sink([&](const unsigned char * data, size_t len) {
|
|
if (len) yield(std::string((const char *) data, len));
|
|
});
|
|
fun(sink);
|
|
})
|
|
{
|
|
}
|
|
|
|
std::string cur;
|
|
size_t pos = 0;
|
|
|
|
size_t read(unsigned char * data, size_t len) override
|
|
{
|
|
if (!coro)
|
|
throw EndOfFile("coroutine has finished");
|
|
|
|
if (pos == cur.size()) {
|
|
if (!cur.empty()) coro();
|
|
cur = coro.get();
|
|
pos = 0;
|
|
}
|
|
|
|
auto n = std::min(cur.size() - pos, len);
|
|
memcpy(data, (unsigned char *) cur.data() + pos, n);
|
|
pos += n;
|
|
|
|
return n;
|
|
}
|
|
};
|
|
|
|
return std::make_unique<SinkToSource>(fun);
|
|
}
|
|
|
|
|
|
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);
|
|
std::string res(len, 0);
|
|
source((unsigned char*) res.data(), len);
|
|
readPadding(len, source);
|
|
return res;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
|
|
}
|