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JRahnamaJRahnama
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Merge common code base for DBReferenceCollection
1 parent 769b982 commit 34805b4

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3 files changed

+286
-4
lines changed

3 files changed

+286
-4
lines changed

‎src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj‎

Lines changed: 3 additions & 3 deletions
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@@ -519,6 +519,9 @@
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<Compile Include="$(CommonSourceRoot)System\Diagnostics\CodeAnalysis.cs">
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<Link>Common\System\Diagnostics\CodeAnalysis.cs</Link>
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</Compile>
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<Compile Include="$(CommonSourceRoot)\Microsoft\Data\ProviderBase\DbReferenceCollection.cs">
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<Link>Microsoft\Data\ProviderBase\DbReferenceCollection.cs</Link>
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</Compile>
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</ItemGroup>
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<ItemGroup Condition="'$(TargetGroup)' == 'netstandard' OR '$(TargetGroup)' == 'netcoreapp' OR '$(IsUAPAssembly)' == 'true'">
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<Compile Include="Microsoft.Data.SqlClient.TypeForwards.cs" />
@@ -616,9 +619,6 @@
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<Compile Include="$(CommonPath)\Microsoft\Data\ProviderBase\DbConnectionInternal.cs">
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<Link>Common\Microsoft\Data\ProviderBase\DbConnectionInternal.cs</Link>
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</Compile>
619-
<Compile Include="$(CommonPath)\Microsoft\Data\ProviderBase\DbReferenceCollection.cs">
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<Link>Common\Microsoft\Data\ProviderBase\DbReferenceCollection.cs</Link>
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</Compile>
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<Compile Include="$(CommonPath)\System\NotImplemented.cs" />
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<Compile Include="Interop\SNINativeMethodWrapper.Common.cs" />
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<Compile Include="Microsoft\Data\Common\DbConnectionOptions.cs" />

‎src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -610,6 +610,9 @@
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<Compile Include="$(CommonSourceRoot)Resources\ResDescriptionAttribute.cs">
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<Link>Resources\ResDescriptionAttribute.cs</Link>
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</Compile>
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<Compile Include="$(CommonSourceRoot)\Microsoft\Data\ProviderBase\DbReferenceCollection.cs">
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<Link>Microsoft\Data\ProviderBase\DbReferenceCollection.cs</Link>
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</Compile>
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</ItemGroup>
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<ItemGroup>
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<Compile Include="Common\src\Microsoft\Data\Common\NameValuePermission.cs" />
@@ -631,7 +634,6 @@
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<Compile Include="Microsoft\Data\ProviderBase\DbConnectionPool.cs" />
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<Compile Include="Microsoft\Data\ProviderBase\DbConnectionPoolCounters.cs" />
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<Compile Include="Microsoft\Data\ProviderBase\DbConnectionPoolIdentity.cs" />
634-
<Compile Include="Microsoft\Data\ProviderBase\DbReferenceCollection.cs" />
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<Compile Include="Microsoft\Data\RelationshipConverter.cs" />
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<Compile Include="Microsoft\Data\SqlClient\AlwaysEncryptedKeyConverter.Cng.cs" />
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<Compile Include="Microsoft\Data\SqlClient\assemblycache.cs" />

‎src/Microsoft.Data.SqlClient/src/Microsoft/Data/ProviderBase/DbReferenceCollection.cs‎

Lines changed: 280 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,280 @@
1+
// 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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// See the LICENSE file in the project root for more information.
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using System;
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using System.Diagnostics;
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using System.Threading;
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namespace Microsoft.Data.ProviderBase
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{
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internal abstract class DbReferenceCollection
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{
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#region Constants
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// Time to wait (in ms) between attempting to get the _itemLock
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private const int LockPollTime = 100;
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// Default size for the collection, and the amount to grow every time the collection is full
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private const int DefaultCollectionSize = 20;
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#endregion
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#region Fields
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// The collection of items we are keeping track of
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private CollectionEntry[] _items;
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// Used to synchronize access to the _items collection
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private readonly object _itemLock;
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// (#ItemsAdded - #ItemsRemoved) - This estimates the number of items that we should have
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// (but doesn't take into account item targets being GC'd)
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private int _estimatedCount;
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// Location of the last item in _items
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private int _lastItemIndex;
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// Indicates that the collection is currently being notified (and, therefore, about to be cleared)
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private volatile bool _isNotifying;
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#endregion
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private struct CollectionEntry
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{
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private int _refInfo; // information about the reference
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private WeakReference<object> _weakReference; // the reference itself.
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public void SetTNewTarget(int refInfo, object target)
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{
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Debug.Assert(!TryGetTarget(out object _), "Entry already has a valid target");
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Debug.Assert(refInfo != 0, "Bad reference info");
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Debug.Assert(target != null, "Invalid target");
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if (_weakReference == null)
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{
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_weakReference = new WeakReference<object>(target, false);
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}
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else
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{
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_weakReference.SetTarget(target);
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}
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_refInfo = refInfo;
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}
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public void RemoveTarget()
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{
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_refInfo = 0;
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_weakReference.SetTarget(null);
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}
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public readonly int RefInfo => _refInfo;
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public readonly bool TryGetTarget(out object target)
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{
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target = null;
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return _refInfo != 0 && _weakReference.TryGetTarget(out target);
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}
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}
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protected DbReferenceCollection()
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{
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_items = new CollectionEntry[DefaultCollectionSize];
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_itemLock = new object();
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_estimatedCount = 0;
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_lastItemIndex = 0;
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}
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abstract public void Add(object value, int refInfo);
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protected void AddItem(object value, int refInfo)
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{
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Debug.Assert(value != null && 0 != refInfo, "AddItem with null value or 0 reference info");
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bool itemAdded = false;
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lock (_itemLock)
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{
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// Try to find a free spot
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for (int i = 0; i <= _lastItemIndex; ++i)
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{
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if (_items[i].RefInfo == 0)
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{
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_items[i].SetTNewTarget(refInfo, value);
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Debug.Assert(_items[i].TryGetTarget(out object _), "missing expected target");
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itemAdded = true;
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break;
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}
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}
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// No free spots, can we just add on to the end?
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if ((!itemAdded) && (_lastItemIndex + 1 < _items.Length))
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{
109+
_lastItemIndex++;
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_items[_lastItemIndex].SetTNewTarget(refInfo, value);
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itemAdded = true;
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}
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// If no free spots and no space at the end, try to find a dead item
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if (!itemAdded)
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{
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for (int i = 0; i <= _lastItemIndex; ++i)
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{
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if (!_items[i].TryGetTarget(out object _))
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{
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_items[i].SetTNewTarget(refInfo, value);
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Debug.Assert(_items[i].TryGetTarget(out object _), "missing expected target");
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itemAdded = true;
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break;
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}
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}
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}
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// If nothing was free, then resize and add to the end
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if (!itemAdded)
131+
{
132+
Array.Resize<CollectionEntry>(ref _items, _items.Length * 2);
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_lastItemIndex++;
134+
_items[_lastItemIndex].SetTNewTarget(refInfo, value);
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}
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_estimatedCount++;
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}
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}
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internal T FindItem<T>(int refInfo, Func<T, bool> filterMethod) where T : class
142+
{
143+
bool lockObtained = false;
144+
try
145+
{
146+
TryEnterItemLock(ref lockObtained);
147+
if (lockObtained)
148+
{
149+
if (_estimatedCount > 0)
150+
{
151+
for (int counter = 0; counter <= _lastItemIndex; counter++)
152+
{
153+
// Check reference info (should be easiest and quickest)
154+
if (_items[counter].RefInfo == refInfo)
155+
{
156+
if (_items[counter].TryGetTarget(out object value))
157+
{
158+
// Make sure the item has the correct type and passes the filtering
159+
if (value is T tempItem && filterMethod(tempItem))
160+
{
161+
return tempItem;
162+
}
163+
}
164+
}
165+
}
166+
}
167+
}
168+
}
169+
finally
170+
{
171+
ExitItemLockIfNeeded(lockObtained);
172+
}
173+
174+
// If we got to here, then no item was found, so return null
175+
return null;
176+
}
177+
178+
public void Notify(int message)
179+
{
180+
bool lockObtained = false;
181+
try
182+
{
183+
TryEnterItemLock(ref lockObtained);
184+
if (lockObtained)
185+
{
186+
try
187+
{
188+
_isNotifying = true;
189+
190+
// Loop through each live item and notify it
191+
if (_estimatedCount > 0)
192+
{
193+
for (int index = 0; index <= _lastItemIndex; ++index)
194+
{
195+
if (_items[index].TryGetTarget(out object value))
196+
{
197+
NotifyItem(message, _items[index].RefInfo, value);
198+
_items[index].RemoveTarget();
199+
}
200+
Debug.Assert(!_items[index].TryGetTarget(out object _), "Unexpected target after notifying");
201+
}
202+
_estimatedCount = 0;
203+
}
204+
205+
// Shrink collection (if needed)
206+
if (_items.Length > 100)
207+
{
208+
_lastItemIndex = 0;
209+
_items = new CollectionEntry[DefaultCollectionSize];
210+
}
211+
}
212+
finally
213+
{
214+
_isNotifying = false;
215+
}
216+
}
217+
}
218+
finally
219+
{
220+
ExitItemLockIfNeeded(lockObtained);
221+
}
222+
}
223+
224+
abstract protected void NotifyItem(int message, int refInfo, object value);
225+
226+
abstract public void Remove(object value);
227+
228+
protected void RemoveItem(object value)
229+
{
230+
Debug.Assert(null != value, "RemoveItem with null");
231+
232+
bool lockObtained = false;
233+
try
234+
{
235+
TryEnterItemLock(ref lockObtained);
236+
237+
if (lockObtained)
238+
{
239+
// Find the value, and then remove the target from our collection
240+
if (_estimatedCount > 0)
241+
{
242+
for (int index = 0; index <= _lastItemIndex; ++index)
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{
244+
if (_items[index].TryGetTarget(out object target) && value == target)
245+
{
246+
_items[index].RemoveTarget();
247+
_estimatedCount--;
248+
break;
249+
}
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}
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}
252+
}
253+
}
254+
finally
255+
{
256+
ExitItemLockIfNeeded(lockObtained);
257+
}
258+
}
259+
260+
// This is polling lock that will abandon getting the lock if _isNotifying is set to true
261+
private void TryEnterItemLock(ref bool lockObtained)
262+
{
263+
// Assume that we couldn't take the lock
264+
lockObtained = false;
265+
// Keep trying to take the lock until either we've taken it, or the collection is being notified
266+
while ((!_isNotifying) && (!lockObtained))
267+
{
268+
Monitor.TryEnter(_itemLock, LockPollTime, ref lockObtained);
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}
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}
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private void ExitItemLockIfNeeded(bool lockObtained)
273+
{
274+
if (lockObtained)
275+
{
276+
Monitor.Exit(_itemLock);
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}
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}
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}
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}

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