Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / _LocalDataStoreMgr.cs / 1305376 / _LocalDataStoreMgr.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== /*============================================================================== ** ** Class: LocalDataStoreMgr ** ** ** Purpose: Class that manages stores of local data. This class is used in ** cooperation with the LocalDataStore class. ** ** =============================================================================*/ namespace System { using System; using System.Collections.Generic; using System.Threading; using System.Runtime.CompilerServices; using System.Diagnostics.Contracts; // This class is an encapsulation of a slot so that it is managed in a secure fashion. // It is constructed by the LocalDataStoreManager, holds the slot and the manager // and cleans up when it is finalized. // This class will not be marked serializable [System.Runtime.InteropServices.ComVisible(true)] public sealed class LocalDataStoreSlot { private LocalDataStoreMgr m_mgr; private int m_slot; private long m_cookie; // Construct the object to encapsulate the slot. internal LocalDataStoreSlot(LocalDataStoreMgr mgr, int slot, long cookie) { m_mgr = mgr; m_slot = slot; m_cookie = cookie; } // Accessors for the two fields of this class. internal LocalDataStoreMgr Manager { get { return m_mgr; } } internal int Slot { get { return m_slot; } } internal long Cookie { get { return m_cookie; } } // Release the slot reserved by this object when this object goes away. ~LocalDataStoreSlot() { LocalDataStoreMgr mgr = m_mgr; if (mgr == null) return; int slot = m_slot; // Mark the slot as free. m_slot = -1; mgr.FreeDataSlot(slot, m_cookie); } } // This class will not be marked serializable sealed internal class LocalDataStoreMgr { private const int InitialSlotTableSize = 64; private const int SlotTableDoubleThreshold = 512; private const int LargeSlotTableSizeIncrease = 128; /*========================================================================= ** Create a data store to be managed by this manager and add it to the ** list. The initial size of the new store matches the number of slots ** allocated in this manager. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public LocalDataStoreHolder CreateLocalDataStore() { // Create a new local data store. LocalDataStore store = new LocalDataStore(this, m_SlotInfoTable.Length); LocalDataStoreHolder holder = new LocalDataStoreHolder(store); bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Add the store to the array list and return it. m_ManagedLocalDataStores.Add(store); } finally { if (tookLock) Monitor.Exit(this); } return holder; } /*========================================================================= * Remove the specified store from the list of managed stores.. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public void DeleteLocalDataStore(LocalDataStore store) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Remove the store to the array list and return it. m_ManagedLocalDataStores.Remove(store); } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================= ** Allocates a data slot by finding an available index and wrapping it ** an object to prevent clients from manipulating it directly, allowing us ** to make assumptions its integrity. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public LocalDataStoreSlot AllocateDataSlot() { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); LocalDataStoreSlot slot; // Check if there are any slots left. int SlotTableSize = m_SlotInfoTable.Length; if (m_FirstAvailableSlot >= SlotTableSize) { // The table is full so we need to increase its size. int NewSlotTableSize; if (SlotTableSize < SlotTableDoubleThreshold) { // The table is still relatively small so double it. NewSlotTableSize = SlotTableSize * 2; } else { // The table is relatively large so simply increase its size by a given amount. NewSlotTableSize = SlotTableSize + LargeSlotTableSizeIncrease; } // Allocate the new slot info table. bool[] NewSlotInfoTable = new bool[NewSlotTableSize]; // Copy the old array into the new one. Array.Copy(m_SlotInfoTable, NewSlotInfoTable, SlotTableSize); m_SlotInfoTable = NewSlotInfoTable; m_FirstAvailableSlot = SlotTableSize; SlotTableSize = NewSlotTableSize; } // Find the first actually available slot. int availableSlot = m_FirstAvailableSlot; for (; ; ) { if (!m_SlotInfoTable[availableSlot]) break; availableSlot++; } m_SlotInfoTable[availableSlot] = true; // availableSlot is the index of the empty slot. // // We do not need to worry about overflowing m_CookieGenerator. It would take centuries // of intensive slot allocations on current machines to get the 2^64 counter to overflow. // We will perform the increment with overflow check just to play it on the safe side. slot = new LocalDataStoreSlot(this, availableSlot, checked(m_CookieGenerator++)); // Save the new "first available slot".hint // In case FreeDataSlot has moved the pointer back, the next slot may not be available. availableSlot ++; while (availableSlot < SlotTableSize) { if (m_SlotInfoTable[availableSlot]) { break; } availableSlot ++; } m_FirstAvailableSlot = availableSlot; // Return the selected slot return slot; } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================== ** Allocate a slot and associate a name with it. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public LocalDataStoreSlot AllocateNamedDataSlot(String name) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Allocate a normal data slot. LocalDataStoreSlot slot = AllocateDataSlot(); // Insert the association between the name and the data slot number // in the hash table. m_KeyToSlotMap.Add(name, slot); return slot; } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================= ** Retrieve the slot associated with a name, allocating it if no such ** association has been defined. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public LocalDataStoreSlot GetNamedDataSlot(String name) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Lookup in the hashtable to try find a slot for the name. LocalDataStoreSlot slot = m_KeyToSlotMap.GetValueOrDefault(name); // If the name is not yet in the hashtable then add it. if (null == slot) return AllocateNamedDataSlot(name); // The name was in the hashtable so return the associated slot. return slot; } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================== ** Eliminate the association of a name with a slot. The actual slot will ** be reclaimed when the finalizer for the slot object runs. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated public void FreeNamedDataSlot(String name) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Remove the name slot association from the hashtable. m_KeyToSlotMap.Remove(name); } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================== ** Free's a previously allocated data slot on ALL the managed data stores. =========================================================================*/ [System.Security.SecuritySafeCritical] // auto-generated internal void FreeDataSlot(int slot, long cookie) { bool tookLock = false; RuntimeHelpers.PrepareConstrainedRegions(); try { Monitor.Enter(this, ref tookLock); // Go thru all the managed stores and set the data on the specified slot to 0. for (int i = 0; i < m_ManagedLocalDataStores.Count; i++) { ((LocalDataStore)m_ManagedLocalDataStores[i]).FreeData(slot, cookie); } // Mark the slot as being no longer occupied. m_SlotInfoTable[slot] = false; if (slot < m_FirstAvailableSlot) m_FirstAvailableSlot = slot; } finally { if (tookLock) Monitor.Exit(this); } } /*========================================================================= ** Check that this is a valid slot for this store =========================================================================*/ public void ValidateSlot(LocalDataStoreSlot slot) { // Make sure the slot was allocated for this store. if (slot == null || slot.Manager != this) throw new ArgumentException(Environment.GetResourceString("Argument_ALSInvalidSlot")); Contract.EndContractBlock(); } /*========================================================================== ** Return the number of allocated slots in this manager. =========================================================================*/ internal int GetSlotTableLength() { return m_SlotInfoTable.Length; } private bool[] m_SlotInfoTable = new bool[InitialSlotTableSize]; private int m_FirstAvailableSlot; private Listm_ManagedLocalDataStores = new List (); private Dictionary m_KeyToSlotMap = new Dictionary (); private long m_CookieGenerator; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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