private int send(FileDescriptor fd, ByteBuffer src, SocketAddress target) throws IOException {
if (src instanceof DirectBuffer) return sendFromNativeBuffer(fd, src, target);
// Substitute a native buffer
int pos = src.position();
int lim = src.limit();
assert (pos <= lim);
int rem = (pos <= lim ? lim - pos : 0);
ByteBuffer bb = Util.getTemporaryDirectBuffer(rem);
try {
bb.put(src);
bb.flip();
// Do not update src until we see how many bytes were written
src.position(pos);
int n = sendFromNativeBuffer(fd, bb, target);
if (n > 0) {
// now update src
src.position(pos + n);
}
return n;
} finally {
Util.releaseTemporaryDirectBuffer(bb);
}
}
@Override
public boolean lock(final boolean lock) {
try {
if (lock) {
if (exclusiveLock()) return true;
if (sharedLock()) return false;
} else {
if (sharedLock()) return true;
}
} catch (final IOException ex) {
Util.stack(ex);
}
throw Util.notExpected((lock ? "Exclusive" : "Shared") + " lock could not be acquired.");
}
public SocketAddress receive(ByteBuffer dst) throws IOException {
if (dst.isReadOnly()) throw new IllegalArgumentException("Read-only buffer");
if (dst == null) throw new NullPointerException();
synchronized (readLock) {
ensureOpen();
// Socket was not bound before attempting receive
if (localAddress() == null) bind(null);
int n = 0;
ByteBuffer bb = null;
try {
begin();
if (!isOpen()) return null;
SecurityManager security = System.getSecurityManager();
readerThread = NativeThread.current();
if (isConnected() || (security == null)) {
do {
n = receive(fd, dst);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
if (n == IOStatus.UNAVAILABLE) return null;
} else {
bb = Util.getTemporaryDirectBuffer(dst.remaining());
for (; ; ) {
do {
n = receive(fd, bb);
} while ((n == IOStatus.INTERRUPTED) && isOpen());
if (n == IOStatus.UNAVAILABLE) return null;
InetSocketAddress isa = (InetSocketAddress) sender;
try {
security.checkAccept(isa.getAddress().getHostAddress(), isa.getPort());
} catch (SecurityException se) {
// Ignore packet
bb.clear();
n = 0;
continue;
}
bb.flip();
dst.put(bb);
break;
}
}
return sender;
} finally {
if (bb != null) Util.releaseTemporaryDirectBuffer(bb);
readerThread = 0;
end((n > 0) || (n == IOStatus.UNAVAILABLE));
assert IOStatus.check(n);
}
}
}
void releaseBuffers() {
for (int i = 0; i < numBufs; i++) {
if (!(bufs[i] instanceof DirectBuffer)) {
Util.releaseTemporaryDirectBuffer(shadow[i]);
}
}
}
/**
* Invoked prior to write to prepare the WSABUF array. Where necessary, it substitutes
* non-direct buffers with direct buffers.
*/
void prepareBuffers() {
shadow = new ByteBuffer[numBufs];
long address = writeBufferArray;
for (int i = 0; i < numBufs; i++) {
ByteBuffer src = bufs[i];
int pos = src.position();
int lim = src.limit();
assert (pos <= lim);
int rem = (pos <= lim ? lim - pos : 0);
long a;
if (!(src instanceof DirectBuffer)) {
// substitute with direct buffer
ByteBuffer bb = Util.getTemporaryDirectBuffer(rem);
bb.put(src);
bb.flip();
src.position(pos); // leave heap buffer untouched for now
shadow[i] = bb;
a = ((DirectBuffer) bb).address();
} else {
shadow[i] = src;
a = ((DirectBuffer) src).address() + pos;
}
unsafe.putAddress(address + OFFSETOF_BUF, a);
unsafe.putInt(address + OFFSETOF_LEN, rem);
address += SIZEOF_WSABUF;
}
}
public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
if ((offset < 0) || (length < 0) || (offset > dsts.length - length))
throw new IndexOutOfBoundsException();
try {
return read(Util.subsequence(dsts, offset, length));
} catch (AsynchronousCloseException x) {
close();
throw x;
}
}
private int receive(FileDescriptor fd, ByteBuffer dst) throws IOException {
int pos = dst.position();
int lim = dst.limit();
assert (pos <= lim);
int rem = (pos <= lim ? lim - pos : 0);
if (dst instanceof DirectBuffer && rem > 0) return receiveIntoNativeBuffer(fd, dst, rem, pos);
// Substitute a native buffer. If the supplied buffer is empty
// we must instead use a nonempty buffer, otherwise the call
// will not block waiting for a datagram on some platforms.
int newSize = Math.max(rem, 1);
ByteBuffer bb = Util.getTemporaryDirectBuffer(newSize);
try {
int n = receiveIntoNativeBuffer(fd, bb, newSize, 0);
bb.flip();
if (n > 0 && rem > 0) dst.put(bb);
return n;
} finally {
Util.releaseTemporaryDirectBuffer(bb);
}
}
/**
* Reads a block from disk.
*
* @param b block to fetch
*/
private void readBlock(final int b) {
if (!bm.cursor(b)) return;
final Buffer bf = bm.current();
try {
if (bf.dirty) writeBlock(bf);
bf.pos = b;
if (b >= blocks) {
blocks = b + 1;
} else {
file.seek(bf.pos * IO.BLOCKSIZE);
file.readFully(bf.data);
}
} catch (final IOException ex) {
Util.stack(ex);
}
}
/**
* Searches for the block containing the entry for the specified pre value. Reads the block and
* returns its offset inside the block.
*
* @param pre pre of the entry to search for
* @return offset of the entry in the block
*/
private int cursor(final int pre) {
int fp = fpre;
int np = npre;
if (pre < fp || pre >= np) {
final int last = used - 1;
int l = 0;
int h = last;
int m = page;
while (l <= h) {
if (pre < fp) h = m - 1;
else if (pre >= np) l = m + 1;
else break;
m = h + l >>> 1;
fp = fpre(m);
np = m == last ? meta.size : fpre(m + 1);
}
if (l > h)
throw Util.notExpected(
"Data Access out of bounds:"
+ "\n- pre value: "
+ pre
+ "\n- #used blocks: "
+ used
+ "\n- #total locks: "
+ blocks
+ "\n- access: "
+ m
+ " ("
+ l
+ " > "
+ h
+ ']');
readPage(m);
}
return pre - fpre << IO.NODEPOWER;
}
/**
* Invoked prior to read to prepare the WSABUF array. Where necessary, it substitutes non-direct
* buffers with direct buffers.
*/
void prepareBuffers() {
shadow = new ByteBuffer[numBufs];
long address = readBufferArray;
for (int i = 0; i < numBufs; i++) {
ByteBuffer dst = bufs[i];
int pos = dst.position();
int lim = dst.limit();
assert (pos <= lim);
int rem = (pos <= lim ? lim - pos : 0);
long a;
if (!(dst instanceof DirectBuffer)) {
// substitute with direct buffer
ByteBuffer bb = Util.getTemporaryDirectBuffer(rem);
shadow[i] = bb;
a = ((DirectBuffer) bb).address();
} else {
shadow[i] = dst;
a = ((DirectBuffer) dst).address() + pos;
}
unsafe.putAddress(address + OFFSETOF_BUF, a);
unsafe.putInt(address + OFFSETOF_LEN, rem);
address += SIZEOF_WSABUF;
}
}
public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
if ((offset < 0) || (length < 0) || (offset > srcs.length - length))
throw new IndexOutOfBoundsException();
// ## Fix IOUtil.write so that we can avoid this array copy
return write0(Util.subsequence(srcs, offset, length));
}
static {
Util.load();
nd = new FileDispatcherImpl();
}
public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
if ((offset < 0) || (length < 0) || (offset > dsts.length - length))
throw new IndexOutOfBoundsException();
return read(Util.subsequence(dsts, offset, length));
}
@Override
public void insert(final int pre, final byte[] entries) {
final int nnew = entries.length;
if (nnew == 0) return;
dirty();
// number of records to be inserted
final int nr = nnew >>> IO.NODEPOWER;
int split = 0;
if (used == 0) {
// special case: insert new data into first block if database is empty
readPage(0);
usedPages.set(0);
++used;
} else if (pre > 0) {
// find the offset within the block where the new records will be inserted
split = cursor(pre - 1) + IO.NODESIZE;
} else {
// all insert operations will add data after first node.
// i.e., there is no "insert before first document" statement
throw Util.notExpected("Insertion at beginning of populated table.");
}
// number of bytes occupied by old records in the current block
final int nold = npre - fpre << IO.NODEPOWER;
// number of bytes occupied by old records which will be moved at the end
final int moved = nold - split;
// special case: all entries fit in the current block
Buffer bf = bm.current();
if (nold + nnew <= IO.BLOCKSIZE) {
Array.move(bf.data, split, nnew, moved);
System.arraycopy(entries, 0, bf.data, split, nnew);
bf.dirty = true;
// increment first pre-values of blocks after the last modified block
for (int i = page + 1; i < used; ++i) fpres[i] += nr;
// update cached variables (fpre is not changed)
npre += nr;
meta.size += nr;
return;
}
// append old entries at the end of the new entries
final byte[] all = new byte[nnew + moved];
System.arraycopy(entries, 0, all, 0, nnew);
System.arraycopy(bf.data, split, all, nnew, moved);
// fill in the current block with new entries
// number of bytes which fit in the first block
int nrem = IO.BLOCKSIZE - split;
if (nrem > 0) {
System.arraycopy(all, 0, bf.data, split, nrem);
bf.dirty = true;
}
// number of new required blocks and remaining bytes
final int req = all.length - nrem;
int needed = req / IO.BLOCKSIZE;
final int remain = req % IO.BLOCKSIZE;
if (remain > 0) {
// check if the last entries can fit in the block after the current one
if (page + 1 < used) {
final int o = occSpace(page + 1) << IO.NODEPOWER;
if (remain <= IO.BLOCKSIZE - o) {
// copy the last records
readPage(page + 1);
bf = bm.current();
System.arraycopy(bf.data, 0, bf.data, remain, o);
System.arraycopy(all, all.length - remain, bf.data, 0, remain);
bf.dirty = true;
// reduce the pre value, since it will be later incremented with nr
fpres[page] -= remain >>> IO.NODEPOWER;
// go back to the previous block
readPage(page - 1);
} else {
// there is not enough space in the block - allocate a new one
++needed;
}
} else {
// this is the last block - allocate a new one
++needed;
}
}
// number of expected blocks: existing blocks + needed block - empty blocks
final int exp = blocks + needed - (blocks - used);
if (exp > fpres.length) {
// resize directory arrays if existing ones are too small
final int ns = Math.max(fpres.length << 1, exp);
fpres = Arrays.copyOf(fpres, ns);
pages = Arrays.copyOf(pages, ns);
}
// make place for the blocks where the new entries will be written
Array.move(fpres, page + 1, needed, used - page - 1);
Array.move(pages, page + 1, needed, used - page - 1);
// write the all remaining entries
while (needed-- > 0) {
freeBlock();
nrem += write(all, nrem);
fpres[page] = fpres[page - 1] + IO.ENTRIES;
pages[page] = (int) bm.current().pos;
}
// increment all fpre values after the last modified block
for (int i = page + 1; i < used; ++i) fpres[i] += nr;
meta.size += nr;
// update cached variables
fpre = fpres[page];
npre = page + 1 < used && fpres[page + 1] < meta.size ? fpres[page + 1] : meta.size;
}
static {
Util.load();
initIDs();
}
