public static ProcedureWALTrailer readTrailer(FSDataInputStream stream, long startPos, long size)
throws IOException {
// Beginning of the Trailer Jump. 17 = 1 byte version + 8 byte magic + 8 byte offset
long trailerPos = size - 17;
if (trailerPos < startPos) {
throw new InvalidWALDataException("Missing trailer: size=" + size + " startPos=" + startPos);
}
stream.seek(trailerPos);
int version = stream.read();
if (version != TRAILER_VERSION) {
throw new InvalidWALDataException(
"Invalid Trailer version. got " + version + " expected " + TRAILER_VERSION);
}
long magic = StreamUtils.readLong(stream);
if (magic != TRAILER_MAGIC) {
throw new InvalidWALDataException(
"Invalid Trailer magic. got " + magic + " expected " + TRAILER_MAGIC);
}
long trailerOffset = StreamUtils.readLong(stream);
stream.seek(trailerOffset);
ProcedureWALEntry entry = readEntry(stream);
if (entry.getType() != ProcedureWALEntry.Type.PROCEDURE_WAL_EOF) {
throw new InvalidWALDataException("Invalid Trailer begin");
}
ProcedureWALTrailer trailer =
ProcedureWALTrailer.newBuilder().setVersion(version).setTrackerPos(stream.getPos()).build();
return trailer;
}
public static void writeEntry(
ByteSlot slot, ProcedureWALEntry.Type type, Procedure proc, Procedure[] subprocs)
throws IOException {
ProcedureWALEntry.Builder builder = ProcedureWALEntry.newBuilder();
builder.setType(type);
builder.addProcedure(Procedure.convert(proc));
if (subprocs != null) {
for (int i = 0; i < subprocs.length; ++i) {
builder.addProcedure(Procedure.convert(subprocs[i]));
}
}
builder.build().writeDelimitedTo(slot);
}
/*
* +-----------------+
* | END OF WAL DATA | <---+
* +-----------------+ |
* | | |
* | Tracker | |
* | | |
* +-----------------+ |
* | version | |
* +-----------------+ |
* | TRAILER_MAGIC | |
* +-----------------+ |
* | offset |-----+
* +-----------------+
*/
public static long writeTrailer(FSDataOutputStream stream, ProcedureStoreTracker tracker)
throws IOException {
long offset = stream.getPos();
// Write EOF Entry
ProcedureWALEntry.newBuilder()
.setType(ProcedureWALEntry.Type.PROCEDURE_WAL_EOF)
.build()
.writeDelimitedTo(stream);
// Write Tracker
tracker.writeTo(stream);
stream.write(TRAILER_VERSION);
StreamUtils.writeLong(stream, TRAILER_MAGIC);
StreamUtils.writeLong(stream, offset);
return stream.getPos() - offset;
}
public static void writeDelete(ByteSlot slot, long procId) throws IOException {
ProcedureWALEntry.Builder builder = ProcedureWALEntry.newBuilder();
builder.setType(ProcedureWALEntry.Type.PROCEDURE_WAL_DELETE);
builder.setProcId(procId);
builder.build().writeDelimitedTo(slot);
}
public static ProcedureWALEntry readEntry(InputStream stream) throws IOException {
return ProcedureWALEntry.parseDelimitedFrom(stream);
}