#include "serialise.hh"
#include "util.hh"
#include <cstring>
#include <cerrno>
namespace nix {
BufferedSink::~BufferedSink()
{
/* We can't call flush() here, because C++ for some insane reason
doesn't allow you to call virtual methods from a destructor. */
assert(!bufPos);
delete[] buffer;
}
void BufferedSink::operator () (const unsigned char * data, size_t len)
{
if (!buffer) 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 + 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, n);
}
FdSink::~FdSink()
{
try { flush(); } catch (...) { ignoreException(); }
}
size_t threshold = 256 * 1024 * 1024;
static void warnLargeDump()
{
printMsg(lvlError, "warning: dumping very large path (> 256 MiB); this may run out of memory");
}
void FdSink::write(const unsigned char * data, size_t len)
{
static bool warned = false;
if (warn && !warned) {
written += len;
if (written > threshold) {
warnLargeDump();
warned = true;
}
}
writeFull(fd, data, len);
}
void Source::operator () (unsigned char * data, size_t len)
{
while (len) {
size_t n = read(data, len);
data += n; len -= n;
}
}
BufferedSource::~BufferedSource()
{
delete[] buffer;
}
size_t BufferedSource::read(unsigned char * data, size_t len)
{
if (!buffer) buffer = new unsigned char[bufSize];
if (!bufPosIn) bufPosIn = readUnbuffered(buffer, bufSize);
/* Copy out the data in the buffer. */
size_t n = len > bufPosIn - bufPosOut ? bufPosIn - bufPosOut : len;
memcpy(data, buffer + 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) throw SysError("reading from file");
if (n == 0) throw EndOfFile("unexpected end-of-file");
return n;
}
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 writeInt(unsigned int n, Sink & sink)
{
unsigned char buf[8];
memset(buf, 0, sizeof(buf));
buf[0] = n & 0xff;
buf[1] = (n >> 8) & 0xff;
buf[2] = (n >> 16) & 0xff;
buf[3] = (n >> 24) & 0xff;
sink(buf, sizeof(buf));
}
void writeLongLong(unsigned long long n, Sink & sink)
{
unsigned char buf[8];
buf[0] = n & 0xff;
buf[1] = (n >> 8) & 0xff;
buf[2] = (n >> 16) & 0xff;
buf[3] = (n >> 24) & 0xff;
buf[4] = (n >> 32) & 0xff;
buf[5] = (n >> 40) & 0xff;
buf[6] = (n >> 48) & 0xff;
buf[7] = (n >> 56) & 0xff;
sink(buf, sizeof(buf));
}
void writeString(const unsigned char * buf, size_t len, Sink & sink)
{
writeInt(len, sink);
sink(buf, len);
writePadding(len, sink);
}
void writeString(const string & s, Sink & sink)
{
writeString((const unsigned char *) s.data(), s.size(), sink);
}
template<class T> void writeStrings(const T & ss, Sink & sink)
{
writeInt(ss.size(), sink);
foreach (typename T::const_iterator, i, ss)
writeString(*i, sink);
}
template void writeStrings(const Paths & ss, Sink & sink);
template void writeStrings(const PathSet & ss, Sink & 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");
}
}
unsigned int readInt(Source & source)
{
unsigned char buf[8];
source(buf, sizeof(buf));
if (buf[4] || buf[5] || buf[6] || buf[7])
throw SerialisationError("implementation cannot deal with > 32-bit integers");
return
buf[0] |
(buf[1] << 8) |
(buf[2] << 16) |
(buf[3] << 24);
}
unsigned long long readLongLong(Source & source)
{
unsigned char buf[8];
source(buf, sizeof(buf));
return
((unsigned long long) buf[0]) |
((unsigned long long) buf[1] << 8) |
((unsigned long long) buf[2] << 16) |
((unsigned long long) buf[3] << 24) |
((unsigned long long) buf[4] << 32) |
((unsigned long long) buf[5] << 40) |
((unsigned long long) buf[6] << 48) |
((unsigned long long) buf[7] << 56);
}
size_t readString(unsigned char * buf, size_t max, Source & source)
{
size_t len = readInt(source);
if (len > max) throw Error("string is too long");
source(buf, len);
readPadding(len, source);
return len;
}
string readString(Source & source)
{
size_t len = readInt(source);
unsigned char * buf = new unsigned char[len];
AutoDeleteArray<unsigned char> d(buf);
source(buf, len);
readPadding(len, source);
return string((char *) buf, len);
}
template<class T> T readStrings(Source & source)
{
unsigned int count = readInt(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);
}
}
