#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,
std::function<void()> eof)
{
struct SinkToSource : Source
{
typedef boost::coroutines2::coroutine<std::string> coro_t;
std::function<void(Sink &)> fun;
std::function<void()> eof;
std::optional<coro_t::pull_type> coro;
bool started = false;
SinkToSource(std::function<void(Sink &)> fun, std::function<void()> eof)
: fun(fun), eof(eof)
{
}
std::string cur;
size_t pos = 0;
size_t read(unsigned char * data, size_t len) override
{
if (!coro)
coro = coro_t::pull_type([&](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);
});
if (!*coro) { eof(); abort(); }
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, eof);
}
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 SerialisationError("string is too long");
source(buf, len);
readPadding(len, source);
return len;
}
string readString(Source & source, size_t max)
{
auto len = readNum<size_t>(source);
if (len > max) throw SerialisationError("string is too long");
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);
}
}
