forked from netty/netty
/
KQueue.java
108 lines (98 loc) · 3.81 KB
/
KQueue.java
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/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.channel.kqueue;
import io.netty.channel.ChannelOption;
import io.netty.channel.unix.FileDescriptor;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.UnstableApi;
/**
* If KQueue is available the JNI resources will be loaded when this class loads.
*/
@UnstableApi
public final class KQueue {
private static final Throwable UNAVAILABILITY_CAUSE;
static {
Throwable cause = null;
if (SystemPropertyUtil.getBoolean("io.netty.transport.noNative", false)) {
cause = new UnsupportedOperationException(
"Native transport was explicit disabled with -Dio.netty.transport.noNative=true");
} else {
FileDescriptor kqueueFd = null;
try {
kqueueFd = Native.newKQueue();
} catch (Throwable t) {
cause = t;
} finally {
if (kqueueFd != null) {
try {
kqueueFd.close();
} catch (Exception ignore) {
// ignore
}
}
}
}
UNAVAILABILITY_CAUSE = cause;
}
/**
* Returns {@code true} if and only if the <a href="https://netty.io/wiki/native-transports.html">{@code
* netty-transport-native-kqueue}</a> is available.
*/
public static boolean isAvailable() {
return UNAVAILABILITY_CAUSE == null;
}
/**
* Ensure that <a href="https://netty.io/wiki/native-transports.html">{@code netty-transport-native-kqueue}</a> is
* available.
*
* @throws UnsatisfiedLinkError if unavailable
*/
public static void ensureAvailability() {
if (UNAVAILABILITY_CAUSE != null) {
throw (Error) new UnsatisfiedLinkError(
"failed to load the required native library").initCause(UNAVAILABILITY_CAUSE);
}
}
/**
* Returns the cause of unavailability of <a href="https://netty.io/wiki/native-transports.html">{@code
* netty-transport-native-kqueue}</a>.
*
* @return the cause if unavailable. {@code null} if available.
*/
public static Throwable unavailabilityCause() {
return UNAVAILABILITY_CAUSE;
}
/**
* Returns {@code true} if the kqueue native transport is both {@linkplain #isAvailable() available} and supports
* {@linkplain ChannelOption#TCP_FASTOPEN_CONNECT client-side TCP FastOpen}.
*
* @return {@code true} if it's possible to use client-side TCP FastOpen via kqueue, otherwise {@code false}.
*/
public static boolean isTcpFastOpenClientSideAvailable() {
return isAvailable() && Native.IS_SUPPORTING_TCP_FASTOPEN_CLIENT;
}
/**
* Returns {@code true} if the kqueue native transport is both {@linkplain #isAvailable() available} and supports
* {@linkplain ChannelOption#TCP_FASTOPEN server-side TCP FastOpen}.
*
* @return {@code true} if it's possible to use server-side TCP FastOpen via kqueue, otherwise {@code false}.
*/
public static boolean isTcpFastOpenServerSideAvailable() {
return isAvailable() && Native.IS_SUPPORTING_TCP_FASTOPEN_SERVER;
}
private KQueue() {
}
}