/*
 * Copyright 2017 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:
 *
 *   http://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.resolver.dns;

import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.UnstableApi;

/**
 * Utility methods related to {@link DnsServerAddressStreamProvider}.
 */
@UnstableApi
public final class DnsServerAddressStreamProviders {
    // TODO(scott): how is this done on Windows? This may require a JNI call to GetNetworkParams
    // https://msdn.microsoft.com/en-us/library/aa365968(VS.85).aspx.
    private static final DnsServerAddressStreamProvider DEFAULT_DNS_SERVER_ADDRESS_STREAM_PROVIDER =
            // If on windows just use the DefaultDnsServerAddressStreamProvider.INSTANCE as otherwise
            // we will log some error which may be confusing.
            PlatformDependent.isWindows() ? DefaultDnsServerAddressStreamProvider.INSTANCE :
                    UnixResolverDnsServerAddressStreamProvider.parseSilently();

    private DnsServerAddressStreamProviders() {
    }

    /**
     * A {@link DnsServerAddressStreamProvider} which inherits the DNS servers from your local host's configuration.
     * <p>
     * Note that only macOS and Linux are currently supported.
     * @return A {@link DnsServerAddressStreamProvider} which inherits the DNS servers from your local host's
     * configuration.
     */
    public static DnsServerAddressStreamProvider platformDefault() {
        return DEFAULT_DNS_SERVER_ADDRESS_STREAM_PROVIDER;
    }
}

@@ -753,16 +753,102 @@
 leApi;%0A%0A
+import java.util.concurrent.TimeUnit;%0Aimport java.util.concurrent.atomic.AtomicLong;%0A%0A
 /**%0A * U
@@ -983,16 +983,204 @@
 iders %7B%0A
+    // We use 5 minutes which is the same as what OpenJDK is using in sun.net.dns.ResolverConfigurationImpl.%0A    private static final long REFRESH_INTERVAL = TimeUnit.MINUTES.toNanos(5);%0A%0A
     // T
@@ -1439,16 +1439,977 @@
 VIDER =%0A
+            new DnsServerAddressStreamProvider() %7B%0A        private volatile DnsServerAddressStreamProvider currentProvider = provider();%0A        private final AtomicLong lastRefresh = new AtomicLong(System.nanoTime());%0A%0A        @Override%0A        public DnsServerAddressStream nameServerAddressStream(String hostname) %7B%0A            long last = lastRefresh.get();%0A            DnsServerAddressStreamProvider current = currentProvider;%0A            if (System.nanoTime() - last %3E REFRESH_INTERVAL) %7B%0A                // This is slightly racy which means it will be possible still use the old configuration for a small%0A                // amount of time, but that's ok.%0A                if (lastRefresh.compareAndSet(last, System.nanoTime())) %7B%0A                    current = currentProvider = provider();%0A                %7D%0A            %7D%0A            return current.nameServerAddressStream(hostname);%0A        %7D%0A%0A        private DnsServerAddressStreamProvider provider() %7B%0A
         
@@ -2576,16 +2576,23 @@
         
+return 
 Platform
@@ -2743,16 +2743,33 @@
 ently();
+%0A        %7D%0A    %7D;
 %0A%0A    pr

Refresh DNS configuration each 5 minutes. (#8468)