Added missing locks and use timeout on all of them in ObjectCacheAppCache (#15902)

* Added missing locks, and ensure we have timeout on all of them

* Wrap the removable of objects from the hashset in a lock

* remove old comment

* Exit correct lock

Author: bergmania

src/Umbraco.Core/Cache/ObjectCacheAppCache.cs

@@ -88,8 +88,10 @@ private IEnumerable<object> SearchByPredicate(Func<string, bool> predicate)
         object[] entries;
         try
         {
-            _locker.EnterReadLock();
-
+            if (_locker.TryEnterReadLock(_readLockTimeout) is false)
+            {
+                throw new TimeoutException("Timeout exceeded to the memory cache when getting item");
+            }
             entries = _keys.Where(predicate)
                 .Select(key => MemoryCache.Get(key))
                 .WhereNotNull()
@@ -125,11 +127,15 @@ private IEnumerable<object> SearchByPredicate(Func<string, bool> predicate)
             if (result == null || SafeLazy.GetSafeLazyValue(result, true) == null)
             {
                 result = SafeLazy.GetSafeLazy(factory);
+
                 MemoryCacheEntryOptions options = GetOptions(timeout, isSliding);
 
                 try
                 {
-                    _locker.EnterWriteLock();
+                    if (_locker.TryEnterWriteLock(_writeLockTimeout) is false)
+                    {
+                        throw new TimeoutException("Timeout exceeded to the memory cache when using factory to insert");
+                    }
 
                     // NOTE: This does an add or update
                     MemoryCache.Set(key, result, options);
@@ -173,12 +179,26 @@ public void Insert(string key, Func<object?> factory, TimeSpan? timeout = null,
         {
             return; // do not store null values (backward compat)
         }
-
         MemoryCacheEntryOptions options = GetOptions(timeout, isSliding);
 
-        // NOTE: This does an add or update
-        MemoryCache.Set(key, result, options);
-        _keys.Add(key);
+        try
+        {
+            if (_locker.TryEnterWriteLock(_writeLockTimeout) is false)
+            {
+                throw new TimeoutException("Cannot insert value into cache, due to timeout for lock.");
+            }
+
+            // NOTE: This does an add or update
+            MemoryCache.Set(key, result, options);
+            _keys.Add(key);
+        }
+        finally
+        {
+            if (_locker.IsWriteLockHeld)
+            {
+                _locker.ExitWriteLock();
+            }
+        }
     }
 
     /// <inheritdoc />
@@ -348,6 +368,23 @@ private MemoryCacheEntryOptions GetOptions(TimeSpan? timeout = null, bool isSlid
         }
 
         // Ensure key is removed from set when evicted from cache
-        return options.RegisterPostEvictionCallback((key, _, _, _) => _keys.Remove((string)key));
+        return options.RegisterPostEvictionCallback((key, _, _, _) =>
+        {
+            try
+            {
+                if (_locker.TryEnterWriteLock(_writeLockTimeout) is false)
+                {
+                    throw new TimeoutException("Timeout exceeded to the memory cache when using factory to insert");
+                }
+                _keys.Remove((string)key);
+            }
+            finally
+            {
+                if (_locker.IsWriteLockHeld)
+                {
+                    _locker.ExitWriteLock();
+                }
+            }
+        });
     }
 }