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package org.jruby.util.io;
import java.io.IOException;
import java.nio.channels.CancelledKeyException;
import java.nio.channels.Channel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.spi.SelectorProvider;
import java.util.Iterator;
import org.jruby.Ruby;
import org.jruby.RubyArray;
import org.jruby.RubyFixnum;
import org.jruby.RubyFloat;
import org.jruby.RubyIO;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;
/**
* This is a reimplementation of MRI's IO#select logic. It has been rewritten
* from an earlier version in JRuby to improve performance and readability.
*
* This version avoids allocating a selector or any data structures to hold
* data about the channels/IOs being selected unless absolutely necessary. It
* also uses simple boolean arrays to track characteristics like whether an IO
* is pending or unselectable, rather than maintaining Set structures. It avoids
* hitting Java Integration code to get IO objects out of the incoming Array.
* Finally, it tries to build a minimal number of data structures an reuse them
* as much as possible.
*/
public class SelectBlob {
public IRubyObject goForIt(ThreadContext context, Ruby runtime, IRubyObject[] args) {
this.runtime = runtime;
try {
processReads(runtime, args, context);
processWrites(runtime, args, context);
if (args.length > 2 && !args[2].isNil()) {
checkArrayType(runtime, args[2]);
// Java's select doesn't do anything about this, so we leave it be.
}
boolean has_timeout = args.length > 3 && !args[3].isNil();
long timeout = !has_timeout ? 0 : getTimeoutFromArg(args[3], runtime);
doSelect(has_timeout, timeout);
processSelectedKeys(runtime);
processPendingAndUnselectable();
tidyUp();
if (readResults == null && writeResults == null && errorResults == null) {
return runtime.getNil();
}
return constructResults(runtime);
} catch (BadDescriptorException e) {
throw runtime.newErrnoEBADFError();
} catch (IOException e) {
throw runtime.newIOErrorFromException(e);
} finally {
if (selector != null) {
try {
selector.close();
} catch (Exception e) {
}
}
}
}
private void processReads(Ruby runtime, IRubyObject[] args, ThreadContext context) throws BadDescriptorException, IOException {
if (!args[0].isNil()) {
// read
checkArrayType(runtime, args[0]);
readArray = (RubyArray) args[0];
readSize = readArray.size();
if (readSize == 0) {
// clear reference; we aren't going to do anything
readArray = null;
} else {
readIOs = new RubyIO[readSize];
for (int i = 0; i < readSize; i++) {
RubyIO ioObj = saveReadIO(i, context);
saveReadBlocking(ioObj, i);
saveBufferedRead(ioObj, i);
trySelectRead(context, i, ioObj);
}
}
}
}
private RubyIO saveReadIO(int i, ThreadContext context) {
IRubyObject obj = readArray.eltOk(i);
RubyIO ioObj = RubyIO.convertToIO(context, obj);
readIOs[i] = ioObj;
return ioObj;
}
private void saveReadBlocking(RubyIO ioObj, int i) {
// save blocking state
if (ioObj.getChannel() instanceof SelectableChannel) {
getReadBlocking()[i] = ((SelectableChannel) ioObj.getChannel()).isBlocking();
}
}
private void saveBufferedRead(RubyIO ioObj, int i) throws BadDescriptorException {
// already buffered data? don't bother selecting
if (ioObj.getOpenFile().getMainStreamSafe().readDataBuffered()) {
getUnselectableReads()[i] = true;
}
}
private void trySelectRead(ThreadContext context, int i, RubyIO ioObj) throws IOException {
if (ioObj.getChannel() instanceof SelectableChannel && registerSelect(context, getSelector(context), i, ioObj, SelectionKey.OP_READ | SelectionKey.OP_ACCEPT)) {
selectedReads++;
if (ioObj.writeDataBuffered()) {
getPendingReads()[i] = true;
}
} else {
if ((ioObj.getOpenFile().getMode() & OpenFile.READABLE) != 0) {
getUnselectableReads()[i] = true;
}
}
}
private void processWrites(Ruby runtime, IRubyObject[] args, ThreadContext context) throws IOException {
if (args.length > 1 && !args[1].isNil()) {
// write
checkArrayType(runtime, args[1]);
writeArray = (RubyArray) args[1];
writeSize = writeArray.size();
if (writeArray.size() == 0) {
// clear reference; we aren't going to do anything
writeArray = null;
} else {
writeIOs = new RubyIO[writeSize];
for (int i = 0; i < writeSize; i++) {
RubyIO ioObj = saveWriteIO(i, context);
saveWriteBlocking(ioObj, i);
trySelectWrite(context, i, ioObj);
}
}
}
}
private RubyIO saveWriteIO(int i, ThreadContext context) {
IRubyObject obj = writeArray.eltOk(i);
RubyIO ioObj = RubyIO.convertToIO(context, obj);
writeIOs[i] = ioObj;
return ioObj;
}
private void saveWriteBlocking(RubyIO ioObj, int i) {
if (ioObj.getChannel() instanceof SelectableChannel) {
// save blocking state
if (readBlocking != null) {
// some read has saved blocking state
// find obj
int readIndex = fastSearch(readIOs, ioObj);
if (readIndex == -1) {
// save blocking only if not found
getWriteBlocking()[i] = ((SelectableChannel) ioObj.getChannel()).isBlocking();
}
} else {
getWriteBlocking()[i] = ((SelectableChannel) ioObj.getChannel()).isBlocking();
}
}
}
private void trySelectWrite(ThreadContext context, int i, RubyIO ioObj) throws IOException {
if (!registerSelect(context, getSelector(context), i, ioObj, SelectionKey.OP_WRITE)) {
selectedReads++;
if ((ioObj.getOpenFile().getMode() & OpenFile.WRITABLE) != 0) {
getUnselectableWrites()[i] = true;
}
}
}
private static long getTimeoutFromArg(IRubyObject timeArg, Ruby runtime) {
long timeout = 0;
if (timeArg instanceof RubyFloat) {
timeout = Math.round(((RubyFloat) timeArg).getDoubleValue() * 1000);
} else if (timeArg instanceof RubyFixnum) {
timeout = Math.round(((RubyFixnum) timeArg).getDoubleValue() * 1000);
} else {
// TODO: MRI also can hadle Bignum here
throw runtime.newTypeError("can't convert " + timeArg.getMetaClass().getName() + " into time interval");
}
if (timeout < 0) {
throw runtime.newArgumentError("negative timeout given");
}
return timeout;
}
private void doSelect(final boolean has_timeout, long timeout) throws IOException {
if (selector != null) {
if (pendingReads == null && unselectableReads == null && unselectableWrites == null) {
if (has_timeout) {
if (timeout == 0) {
selector.selectNow();
} else {
selector.select(timeout);
}
} else {
selector.select();
}
} else {
selector.selectNow();
}
}
}
private void processSelectedKeys(Ruby runtime) {
if (selector != null) {
for (Iterator i = selector.selectedKeys().iterator(); i.hasNext();) {
SelectionKey key = (SelectionKey) i.next();
int ioIndex = (Integer) key.attachment();
try {
int interestAndReady = key.interestOps() & key.readyOps();
if (readArray != null && (interestAndReady & (SelectionKey.OP_READ | SelectionKey.OP_ACCEPT | SelectionKey.OP_CONNECT)) != 0) {
getReadResults().append(readArray.eltOk(ioIndex));
if (pendingReads != null) {
pendingReads[ioIndex] = false;
}
}
if (writeArray != null && (interestAndReady & (SelectionKey.OP_WRITE)) != 0) {
getWriteResults().append(writeArray.eltOk(ioIndex));
}
} catch (CancelledKeyException cke) {
// TODO: is this the right thing to do?
int interest = key.interestOps();
if (readArray != null && (interest & (SelectionKey.OP_READ | SelectionKey.OP_ACCEPT | SelectionKey.OP_CONNECT)) != 0) {
if (pendingReads != null) {
pendingReads[ioIndex] = false;
}
if (errorResults != null) {
errorResults = RubyArray.newArray(runtime, readArray.size() + writeArray.size());
}
if (fastSearch(errorResults.toJavaArrayUnsafe(), readIOs[ioIndex]) == -1) {
// only add to error if not there
getErrorResults().append(readArray.eltOk(ioIndex));
}
}
if (writeArray != null && (interest & (SelectionKey.OP_WRITE)) != 0) {
if (fastSearch(errorResults.toJavaArrayUnsafe(), writeIOs[ioIndex]) == -1) {
// only add to error if not there
errorResults.append(writeArray.eltOk(ioIndex));
}
}
}
}
}
}
private void processPendingAndUnselectable() {
if (pendingReads != null) {
for (int i = 0; i < pendingReads.length; i++) {
if (pendingReads[i]) {
getReadResults().append(readArray.eltOk(i));
}
}
}
if (unselectableReads != null) {
for (int i = 0; i < unselectableReads.length; i++) {
if (unselectableReads[i]) {
getReadResults().append(readArray.eltOk(i));
}
}
}
if (unselectableWrites != null) {
for (int i = 0; i < unselectableWrites.length; i++) {
if (unselectableWrites[i]) {
getWriteResults().append(writeArray.eltOk(i));
}
}
}
}
private void tidyUp() throws IOException {
// make all sockets blocking as configured again
if (selector != null) {
selector.close(); // close unregisters all channels, so we can safely reset blocking modes
}
if (readBlocking != null) {
for (int i = 0; i < readBlocking.length; i++) {
if (readBlocking[i] != null) {
((SelectableChannel) readIOs[i].getChannel()).configureBlocking(readBlocking[i]);
}
}
}
if (writeBlocking != null) {
for (int i = 0; i < writeBlocking.length; i++) {
if (writeBlocking[i] != null) {
((SelectableChannel) writeIOs[i].getChannel()).configureBlocking(writeBlocking[i]);
}
}
}
}
private RubyArray getReadResults() {
if (readResults == null) {
readResults = RubyArray.newArray(runtime, readArray.size());
}
return readResults;
}
private RubyArray getWriteResults() {
if (writeResults == null) {
writeResults = RubyArray.newArray(runtime, writeArray.size());
}
return writeResults;
}
private RubyArray getErrorResults() {
if (errorResults != null) {
errorResults = RubyArray.newArray(runtime, readArray.size() + writeArray.size());
}
return errorResults;
}
private Selector getSelector(ThreadContext context) throws IOException {
if (selector == null) {
selector = SelectorFactory.openWithRetryFrom(context.getRuntime(), SelectorProvider.provider());
}
return selector;
}
private Boolean[] getReadBlocking() {
if (readBlocking == null) {
readBlocking = new Boolean[readSize];
}
return readBlocking;
}
private Boolean[] getWriteBlocking() {
if (writeBlocking == null) {
writeBlocking = new Boolean[writeSize];
}
return writeBlocking;
}
private boolean[] getUnselectableReads() {
if (unselectableReads == null) {
unselectableReads = new boolean[readSize];
}
return unselectableReads;
}
private boolean[] getUnselectableWrites() {
if (unselectableWrites == null) {
unselectableWrites = new boolean[readSize];
}
return unselectableWrites;
}
private boolean[] getPendingReads() {
if (pendingReads == null) {
pendingReads = new boolean[readSize];
}
return pendingReads;
}
private IRubyObject constructResults(Ruby runtime) {
return RubyArray.newArrayLight(runtime, readResults == null ? RubyArray.newEmptyArray(runtime) : readResults, writeResults == null ? RubyArray.newEmptyArray(runtime) : writeResults, errorResults == null ? RubyArray.newEmptyArray(runtime) : errorResults);
}
private int fastSearch(Object[] ary, Object obj) {
for (int i = 0; i < ary.length; i++) {
if (ary[i] == obj) {
return i;
}
}
return -1;
}
private static void checkArrayType(Ruby runtime, IRubyObject obj) {
if (!(obj instanceof RubyArray)) {
throw runtime.newTypeError("wrong argument type "
+ obj.getMetaClass().getName() + " (expected Array)");
}
}
private static boolean registerSelect(ThreadContext context, Selector selector, Object obj, RubyIO ioObj, int ops) throws IOException {
Channel channel = ioObj.getChannel();
if (channel == null || !(channel instanceof SelectableChannel)) {
return false;
}
((SelectableChannel) channel).configureBlocking(false);
int real_ops = ((SelectableChannel) channel).validOps() & ops;
SelectionKey key = ((SelectableChannel) channel).keyFor(selector);
if (key == null) {
((SelectableChannel) channel).register(selector, real_ops, obj);
} else {
key.interestOps(key.interestOps() | real_ops);
}
return true;
}
Ruby runtime;
RubyArray readArray = null;
int readSize = 0;
RubyIO[] readIOs = null;
boolean[] unselectableReads = null;
boolean[] pendingReads = null;
Boolean[] readBlocking = null;
int selectedReads = 0;
RubyArray writeArray = null;
int writeSize = 0;
RubyIO[] writeIOs = null;
boolean[] unselectableWrites = null;
Boolean[] writeBlocking = null;
int selectedWrites = 0;
Selector selector = null;
RubyArray readResults = null;
RubyArray writeResults = null;
RubyArray errorResults = null;
}