Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/PartitionResolver.cs

@@ -0,0 +1,189 @@
+//------------------------------------------------------------------------------
+// <copyright file="PartitionResolver.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>                                                                
+//------------------------------------------------------------------------------
+
+namespace System.Web {
+
+    using System;
+    using System.Configuration;
+    using System.Collections;
+    using System.Threading;
+    using System.IO;
+    using System.Web;
+    using System.Web.Caching;
+    using System.Web.Util;
+    using System.Data;
+    using System.Data.SqlClient;
+    using System.Text;
+    using System.Security.Principal;
+    using System.Xml;
+    using System.Collections.Specialized; 
+    using System.Configuration.Provider;
+    using System.Globalization;
+    using System.Web.Management;
+    using System.Web.Hosting;
+    using System.Web.Configuration;
+    using System.Security.Permissions;
+
+    public interface IPartitionResolver {
+        void Initialize();
+        string ResolvePartition(Object key);
+    }
+
+    internal interface IPartitionInfo {
+        string GetTracingPartitionString();
+    }
+
+    internal delegate IPartitionInfo CreatePartitionInfo(string connectionString);
+    
+    class PartitionManager  : IDisposable {
+        internal PartitionManager(CreatePartitionInfo createCallback) {
+            _createCallback = createCallback;
+        }
+    
+        HybridDictionary    _partitions = new HybridDictionary();
+        ReaderWriterLock    _lock = new ReaderWriterLock();
+        CreatePartitionInfo _createCallback;
+
+        internal object GetPartition(IPartitionResolver partitionResolver, string id) {
+            if (EtwTrace.IsTraceEnabled(EtwTraceLevel.Verbose, EtwTraceFlags.Infrastructure))
+                EtwTrace.Trace(EtwTraceType.ETW_TYPE_SESSIONSTATE_PARTITION_START, HttpContext.Current.WorkerRequest, partitionResolver.GetType().FullName, id);
+            
+            string partitionString = null;
+            string errorMessage = null;
+            IPartitionInfo partitionInfo = null;
+            try {
+                try {
+                    partitionString = partitionResolver.ResolvePartition(id);
+
+                    if (partitionString == null) {
+                        throw new HttpException(
+                                SR.GetString(SR.Bad_partition_resolver_connection_string, partitionResolver.GetType().FullName));
+                    }
+                }
+                catch (Exception e) {
+                    errorMessage = e.Message;
+                    throw;
+                }
+
+                try {
+                    _lock.AcquireReaderLock(-1);
+                    partitionInfo = (IPartitionInfo)_partitions[partitionString];
+                    if (partitionInfo != null) {
+                        Debug.Trace("PartitionManager", "id=" + id + "; partitionString=" + partitionString);
+                        return partitionInfo;
+                    }
+
+                }
+                finally {
+                    if (_lock.IsReaderLockHeld) {
+                        _lock.ReleaseReaderLock();
+                    }
+                }
+
+                // Not found.  Has to add it.
+                try {
+                    _lock.AcquireWriterLock(-1);
+                    // One more time
+                    partitionInfo = (IPartitionInfo)_partitions[partitionString];
+                    if (partitionInfo == null) {
+                        partitionInfo = _createCallback(partitionString);
+
+                        Debug.Trace("PartitionManager", "Add a new partition; id=" + id + "; partitionString=" + partitionString);
+                        _partitions.Add(partitionString, partitionInfo);
+                    }
+
+                    Debug.Trace("PartitionManager", "id=" + id + "; partitionString=" + partitionString);
+                    return partitionInfo;
+                }
+                finally {
+                    if (_lock.IsWriterLockHeld) {
+                        _lock.ReleaseWriterLock();
+                    }
+                }
+            }
+            finally {
+                if (EtwTrace.IsTraceEnabled(EtwTraceLevel.Verbose, EtwTraceFlags.Infrastructure)) {
+                    string msg = errorMessage;
+                    if (msg == null) {
+                        if (partitionInfo != null) {
+                            msg = partitionInfo.GetTracingPartitionString();
+                        }
+                        else {
+                            msg = String.Empty;
+                        }
+                    }
+                    EtwTrace.Trace(EtwTraceType.ETW_TYPE_SESSIONSTATE_PARTITION_END, HttpContext.Current.WorkerRequest, msg);
+                }
+            }
+        }
+
+        public void Dispose() {
+            if (_partitions == null) {
+                return;
+            }
+            
+            try {
+                _lock.AcquireWriterLock(-1);
+                if (_partitions != null) {
+                    foreach (PartitionInfo partitionInfo in _partitions.Values) {
+                        partitionInfo.Dispose();
+                    }
+
+                    _partitions = null;
+                }
+            }
+            catch {
+                // ignore exceptions in dispose
+            }
+            finally {
+                if (_lock.IsWriterLockHeld) {
+                    _lock.ReleaseWriterLock();
+                }
+            }
+        }
+    }
+    
+    internal class PartitionInfo : IDisposable, IPartitionInfo {
+        ResourcePool    _rpool;
+
+        internal PartitionInfo(ResourcePool rpool) {
+            _rpool = rpool;
+        }
+        
+        internal object RetrieveResource() {
+            return _rpool.RetrieveResource();
+        }
+    
+        internal void StoreResource(IDisposable o) {
+            _rpool.StoreResource(o);
+        }
+
+        protected virtual string TracingPartitionString {
+            get {
+                return String.Empty;
+            }
+        }
+
+        string IPartitionInfo.GetTracingPartitionString() {
+            return TracingPartitionString;
+        }
+
+        public void Dispose() {
+            if (_rpool == null) {
+                return;
+            }
+            
+            lock (this) {
+                if (_rpool != null) {
+                    _rpool.Dispose();
+                    _rpool = null;
+                }
+            }
+        }
+    };
+
+    
+}