private static void PutEntry(IPAddress ip, CachedIPHostEntry entry)
{
lock (CachedIPHostEntryDict)
{
if (CachedIPHostEntryDict.TryAdd(ip, entry))
{
LogHelper.Debug($"Start resolve IPHostEntry for {ip}: IsResolved={entry.IsResolved}, HasErrors={entry.HasErrors}, ToolTipText={entry.DisplayText}");
}
else
{
CachedIPHostEntryDict[ip] = entry;
LogHelper.Debug($"End resolve IPHostEntry for {ip}: IsResolved={entry.IsResolved}, HasErrors={entry.HasErrors}, ToolTipText={entry.DisplayText}");
}
}
}
public static async Task <bool?> ResolveIpAddress(string ip, Action <CachedIPHostEntry> callback = null)
{
return(await Task.Run(() =>
{
if (!IsIPValid(ip))
{
callback?.Invoke(CachedIPHostEntry.EMTPY);
return false;
}
IPAddress ipa = null;
try
{
ipa = IPAddress.Parse(ip);
if (CachedIPHostEntryDict.TryGetValue(ipa, out var entry))
{
if (entry.IsResolved || entry.HasErrors)
{
callback?.Invoke(entry);
return true;
}
NotifyCollectionChangedEventHandler add = (sender, args) =>
{
if (args.Action == NotifyCollectionChangedAction.Replace)
{
var entry = (KeyValuePair <IPAddress, CachedIPHostEntry>)args.NewItems[0];
if (entry.Key == ipa)
{
callback?.Invoke(entry.Value);
}
}
};
CachedIPHostEntryDict.CollectionChanged += add;
CachedIPHostEntryDict.CollectionChanged += (s, e) => CachedIPHostEntryDict.CollectionChanged -= add;
return (bool?)null;
}
else
{
PutEntry(ipa, CachedIPHostEntry.RESOLVING); // reserve slot
callback?.Invoke(CachedIPHostEntry.RESOLVING);
// http://www.dotnetframework.org/default.aspx/4@0/4@0/DEVDIV_TFS/Dev10/Releases/RTMRel/ndp/fx/src/Net/System/Net/DNS@cs/1305376/DNS@cs
IPHostEntry resolvedEntry = System.Net.Dns.GetHostEntry(ipa);
PutEntry(ipa, CachedIPHostEntry.WrapHostEntry(resolvedEntry));
callback?.Invoke(CachedIPHostEntryDict[ipa]);
return true;
}
}
catch (Exception e)
{
LogHelper.Debug($"Unable to resolve {ip}, message was {e.Message}");
var ret = CachedIPHostEntry.CreateErrorEntry(ipa, e);
PutEntry(ipa, ret);
callback?.Invoke(ret);
return false;
}
}).ConfigureAwait(false));
}