/** @inheritDoc */
public int writeBuf(int fd, byte buffer[], int off, int len) throws IOException {
int result = 0;
byte[] buf = buffer;
if (off != 0) {
buf = new byte[len];
System.arraycopy(buffer, off, buf, 0, len);
}
if (DEBUG) {
System.err.println("writeBuf(" + fd + ") before write.");
}
result = libc.write(fd, buf, len); // We rely on open0() for setting the socket to non-blocking
if (result < 0) {
int err_code = LibCUtil.errno();
if (err_code == LibC.EWOULDBLOCK) {
VMThread.getSystemEvents().waitForWriteEvent(fd);
if (DEBUG) {
System.err.println("writeBuf(" + fd + ") returned from select. retry.");
}
result =
libc.write(fd, buf, len); // We rely on open0() for setting the socket to non-blocking
}
if (DEBUG) {
System.err.println("writeBuf(" + fd + ") error:");
}
LibCUtil.errCheckNeg(result);
}
return result;
}
/** @inheritDoc */
public int readBuf(int fd, byte b[], int offset, int length) throws IOException {
byte[] buf = b;
int result;
if (offset != 0) {
if (DEBUG) {
System.err.println("readBuf() into temp buf");
}
buf = new byte[length];
}
if (NBIO_WORKS) {
result =
libc.read(fd, buf, length); // We rely on open0() for setting the socket to non-blocking
if (result < 0) {
int err_code = LibCUtil.errno();
if (err_code == LibC.EWOULDBLOCK) {
if (DEBUG) {
System.err.println("Wait for read in select...");
}
VMThread.getSystemEvents().waitForReadEvent(fd);
result =
libc.read(
fd, buf, length); // We rely on open0() for setting the socket to non-blocking
}
LibCUtil.errCheckNeg(result);
}
} else {
// If non-blocking IO doesn't seems to be working, try this hack...
int bAvail = available(fd); // may throw IOException
if (bAvail == 0) {
if (DEBUG) {
System.err.println("Wait for read in select...");
}
VMThread.getSystemEvents().waitForReadEvent(fd);
bAvail = available(fd);
if (bAvail == 0) { // woke up because connection is closed
if (DEBUG) {
System.err.println("readBuf(" + fd + ") signalling EOF.");
}
return -1; // signal EOF
}
}
if (DEBUG) {
System.err.println("readBuf(" + fd + ") returned from select. retry.");
}
int n = Math.min(bAvail, length); // don't read more than is asked for...
result = libc.read(fd, buf, n); // only read what we know is there...
LibCUtil.errCheckNeg(result);
}
if (result == 0) {
// If remote side has shut down the connection gracefully, and all
// data has been received, recv() will complete immediately with
// zero bytes received.
//
// This is true for Win32/CE and Linux
if (DEBUG) {
System.err.println("readBuf(" + fd + ") saw remote side shutdown.");
}
result = -1;
}
if (offset != 0 && result > 0) {
System.arraycopy(buf, 0, b, offset, result);
}
if (DEBUG) {
System.out.println("readBuf(" + fd + ") = " + result);
}
return result;
}
