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-rw-r--r--nix/libutil/serialise.cc259
1 files changed, 259 insertions, 0 deletions
diff --git a/nix/libutil/serialise.cc b/nix/libutil/serialise.cc
new file mode 100644
index 0000000000..6b71f52c15
--- /dev/null
+++ b/nix/libutil/serialise.cc
@@ -0,0 +1,259 @@
+#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(); }
+}
+
+
+void FdSink::write(const unsigned char * data, size_t len)
+{
+ 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);
+
+
+}