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simonrozsivalsimonrozsival
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[Android] Add NetworkChange implementation using PeriodicTimer (#80548) (#81350)
* Add NetworkChange implementation using PeriodicTimer * Code cleanup * Rename functions * Update csproj
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‎src/libraries/System.Net.NetworkInformation/src/System.Net.NetworkInformation.csproj

Lines changed: 3 additions & 2 deletions
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@@ -153,8 +153,9 @@
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<Compile Include="System\Net\NetworkInformation\AndroidIPInterfaceProperties.cs" />
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<Compile Include="System\Net\NetworkInformation\AndroidIPv4InterfaceProperties.cs" />
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<Compile Include="System\Net\NetworkInformation\AndroidIPv6InterfaceProperties.cs" />
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<Compile Include="System\Net\NetworkInformation\NetworkInterfacePal.Android.cs" />
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<Compile Include="System\Net\NetworkInformation\AndroidNetworkInterface.cs" />
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<Compile Include="System\Net\NetworkInformation\NetworkInterfacePal.Android.cs" />
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<Compile Include="System\Net\NetworkInformation\NetworkAddressChange.Android.cs" />
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</ItemGroup>
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<!-- OSX -->
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<ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'OSX' or '$(TargetPlatformIdentifier)' == 'iOS' or '$(TargetPlatformIdentifier)' == 'tvOS' or '$(TargetPlatformIdentifier)' == 'FreeBSD'">
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<ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'FreeBSD'">
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<Compile Include="$(CommonPath)Interop\FreeBSD\Interop.Libraries.cs" Link="Common\Interop\FreeBSD\Interop.Libraries.cs" />
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</ItemGroup>
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<ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'Linux' or '$(TargetPlatformIdentifier)' == 'Android' or '$(TargetPlatformIdentifier)' == 'FreeBSD'">
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<ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'Linux' or '$(TargetPlatformIdentifier)' == 'FreeBSD'">
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<Compile Include="System\Net\NetworkInformation\NetworkAddressChange.Unix.cs" />
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<Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.NetworkChange.cs" Link="Common\Interop\Unix\System.Native\Interop.NetworkChange.cs" />
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</ItemGroup>

‎src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/NetworkAddressChange.Android.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Runtime.Versioning;
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using System.Threading;
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using System.Threading.Tasks;
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namespace System.Net.NetworkInformation
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{
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public partial class NetworkChange
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{
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private static readonly TimeSpan s_timerInterval = TimeSpan.FromSeconds(2);
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private static readonly object s_lockObj = new();
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private static Task? s_loopTask;
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private static CancellationTokenSource? s_cancellationTokenSource;
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private static IPAddress[]? s_lastIpAddresses;
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[UnsupportedOSPlatform("illumos")]
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[UnsupportedOSPlatform("solaris")]
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public static event NetworkAddressChangedEventHandler? NetworkAddressChanged
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{
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add
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{
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if (value != null)
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{
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lock (s_lockObj)
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{
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if (s_addressChangedSubscribers.Count == 0 &&
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s_availabilityChangedSubscribers.Count == 0)
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{
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CreateAndStartLoop();
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}
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else
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{
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Debug.Assert(s_loopTask is not null);
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}
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s_addressChangedSubscribers.TryAdd(value, ExecutionContext.Capture());
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}
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}
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}
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remove
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{
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if (value != null)
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{
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lock (s_lockObj)
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{
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bool hadAddressChangedSubscribers = s_addressChangedSubscribers.Count != 0;
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s_addressChangedSubscribers.Remove(value);
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if (hadAddressChangedSubscribers && s_addressChangedSubscribers.Count == 0 &&
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s_availabilityChangedSubscribers.Count == 0)
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{
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StopLoop();
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}
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}
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}
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}
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}
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[UnsupportedOSPlatform("illumos")]
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[UnsupportedOSPlatform("solaris")]
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public static event NetworkAvailabilityChangedEventHandler? NetworkAvailabilityChanged
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{
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add
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{
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if (value != null)
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{
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lock (s_lockObj)
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{
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if (s_addressChangedSubscribers.Count == 0 &&
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s_availabilityChangedSubscribers.Count == 0)
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{
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CreateAndStartLoop();
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}
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else
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{
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Debug.Assert(s_loopTask is not null);
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}
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s_availabilityChangedSubscribers.TryAdd(value, ExecutionContext.Capture());
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}
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}
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}
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remove
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{
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if (value != null)
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{
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lock (s_lockObj)
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{
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bool hadSubscribers = s_addressChangedSubscribers.Count != 0 ||
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s_availabilityChangedSubscribers.Count != 0;
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s_availabilityChangedSubscribers.Remove(value);
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if (hadSubscribers && s_addressChangedSubscribers.Count == 0 &&
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s_availabilityChangedSubscribers.Count == 0)
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{
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StopLoop();
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}
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}
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}
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}
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}
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private static void CreateAndStartLoop()
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{
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Debug.Assert(s_cancellationTokenSource is null);
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Debug.Assert(s_loopTask is null);
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s_cancellationTokenSource = new CancellationTokenSource();
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s_loopTask = Task.Run(() => PeriodicallyCheckIfNetworkChanged(s_cancellationTokenSource.Token));
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}
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private static void StopLoop()
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{
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Debug.Assert(s_cancellationTokenSource is not null);
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Debug.Assert(s_loopTask is not null);
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s_cancellationTokenSource.Cancel();
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s_loopTask = null;
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s_cancellationTokenSource = null;
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s_lastIpAddresses = null;
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}
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private static async Task PeriodicallyCheckIfNetworkChanged(CancellationToken cancellationToken)
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{
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using var timer = new PeriodicTimer(s_timerInterval);
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try
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{
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while (await timer.WaitForNextTickAsync(cancellationToken).ConfigureAwait(false)
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&& !cancellationToken.IsCancellationRequested)
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{
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CheckIfNetworkChanged();
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}
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}
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catch (OperationCanceledException)
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{
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}
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}
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private static void CheckIfNetworkChanged()
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{
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var newAddresses = GetIPAddresses();
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if (s_lastIpAddresses is IPAddress[] oldAddresses && NetworkChanged(oldAddresses, newAddresses))
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{
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OnNetworkChanged();
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}
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s_lastIpAddresses = newAddresses;
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}
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private static IPAddress[] GetIPAddresses()
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{
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var addresses = new List<IPAddress>();
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var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
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foreach (var networkInterface in networkInterfaces)
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{
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var properties = networkInterface.GetIPProperties();
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foreach (var addressInformation in properties.UnicastAddresses)
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{
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addresses.Add(addressInformation.Address);
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}
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}
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return addresses.ToArray();
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}
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private static bool NetworkChanged(IPAddress[] oldAddresses, IPAddress[] newAddresses)
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{
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if (oldAddresses.Length != newAddresses.Length)
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{
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return true;
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}
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for (int i = 0; i < newAddresses.Length; i++)
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{
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if (Array.IndexOf(oldAddresses, newAddresses[i]) == -1)
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{
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return true;
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}
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}
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return false;
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}
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private static void OnNetworkChanged()
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{
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Dictionary<NetworkAddressChangedEventHandler, ExecutionContext?>? addressChangedSubscribers = null;
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Dictionary<NetworkAvailabilityChangedEventHandler, ExecutionContext?>? availabilityChangedSubscribers = null;
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lock (s_lockObj)
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{
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if (s_addressChangedSubscribers.Count > 0)
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{
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addressChangedSubscribers = new Dictionary<NetworkAddressChangedEventHandler, ExecutionContext?>(s_addressChangedSubscribers);
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}
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if (s_availabilityChangedSubscribers.Count > 0)
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{
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availabilityChangedSubscribers = new Dictionary<NetworkAvailabilityChangedEventHandler, ExecutionContext?>(s_availabilityChangedSubscribers);
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}
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}
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if (addressChangedSubscribers != null)
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{
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foreach (KeyValuePair<NetworkAddressChangedEventHandler, ExecutionContext?>
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subscriber in addressChangedSubscribers)
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{
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NetworkAddressChangedEventHandler handler = subscriber.Key;
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ExecutionContext? ec = subscriber.Value;
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if (ec == null) // Flow suppressed
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{
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handler(null, EventArgs.Empty);
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}
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else
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{
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ExecutionContext.Run(ec, s_runAddressChangedHandler, handler);
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}
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}
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}
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if (availabilityChangedSubscribers != null)
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{
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bool isAvailable = NetworkInterface.GetIsNetworkAvailable();
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NetworkAvailabilityEventArgs args = isAvailable ? s_availableEventArgs : s_notAvailableEventArgs;
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ContextCallback callbackContext = isAvailable ? s_runHandlerAvailable : s_runHandlerNotAvailable;
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foreach (KeyValuePair<NetworkAvailabilityChangedEventHandler, ExecutionContext?>
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subscriber in availabilityChangedSubscribers)
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{
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NetworkAvailabilityChangedEventHandler handler = subscriber.Key;
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ExecutionContext? ec = subscriber.Value;
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if (ec == null) // Flow suppressed
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{
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handler(null, args);
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}
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else
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{
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ExecutionContext.Run(ec, callbackContext, handler);
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}
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}
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}
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}
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}
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}

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