_LocalDataStore.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / _LocalDataStore.cs / 1 / _LocalDataStore.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*==============================================================================
** 
** Class: LocalDataStore 
**
** 
** Purpose: Class that stores local data. This class is used in cooperation
**          with the _LocalDataStoreMgr class.
**
** 
=============================================================================*/
 
namespace System { 

    using System; 
    using System.Threading;
    using System.Runtime.CompilerServices;

    // This class will not be marked serializable 
    internal class LocalDataStore
    { 
        /*========================================================================= 
        ** DON'T CHANGE THESE UNLESS YOU MODIFY LocalDataStoreBaseObject in vm\object.h
        =========================================================================*/ 
        private Object[] m_DataTable;
        private LocalDataStoreMgr m_Manager;
#pragma warning disable 414  // Field is not used from managed.
        private int DONT_USE_InternalStore = 0; // pointer 
#pragma warning restore 414
 
        /*========================================================================= 
        ** Initialize the data store.
        =========================================================================*/ 
        public LocalDataStore(LocalDataStoreMgr mgr, int InitialCapacity)
        {
            if (null == mgr)
                throw new ArgumentNullException("mgr"); 

            // Store the manager of the local data store. 
            m_Manager = mgr; 

            // Allocate the array that will contain the data. 
            m_DataTable = new Object[InitialCapacity];
        }

        /*========================================================================= 
        ** Retrieves the value from the specified slot.
        =========================================================================*/ 
        public Object GetData(LocalDataStoreSlot slot) 
        {
            Object o = null; 

            // Validate the slot.
            m_Manager.ValidateSlot(slot);
 
            // Cache the slot index to avoid synchronization issues.
            int slotIdx = slot.Slot; 
 
            if (slotIdx >= 0)
            { 
                // Delay expansion of m_DataTable if we can
                if (slotIdx >= m_DataTable.Length)
                    return null;
 
                // Retrieve the data from the given slot.
                o = m_DataTable[slotIdx]; 
            } 

            // Check if the slot has become invalid. 
            if (!slot.IsValid())
                throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SlotHasBeenFreed"));
            return o;
        } 

        /*========================================================================== 
        ** Sets the data in the specified slot. 
        =========================================================================*/
        public void SetData(LocalDataStoreSlot slot, Object data) 
        {
            // Validate the slot.
            m_Manager.ValidateSlot(slot);
 
            // I can't think of a way to avoid the race described in the
            // LocalDataStoreSlot finalizer method without a lock. 
            bool tookLock = false; 
            RuntimeHelpers.PrepareConstrainedRegions();
            try { 
                Monitor.ReliableEnter(m_Manager, ref tookLock);
                if (!slot.IsValid())
                    throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_SlotHasBeenFreed"));
 
                // Do the actual set operation.
                SetDataInternal(slot.Slot, data, true /*bAlloc*/ ); 
            } 
            finally {
                if (tookLock) 
                    Monitor.Exit(m_Manager);
            }

        } 

        /*========================================================================= 
        ** This method does the actual work of setting the data. 
        =========================================================================*/
        internal void SetDataInternal(int slot, Object data, bool bAlloc) 
        {
            // We try to delay allocate the dataTable (in cases like the manager clearing a
            // just-freed slot in all stores
            if (slot >= m_DataTable.Length) 
            {
                if (!bAlloc) 
                    return; 
                SetCapacity(m_Manager.GetSlotTableLength());
            } 

            // Set the data on the given slot.
            m_DataTable[slot] = data;
        } 

 		/*========================================================================== 
		** Method used to set the capacity of the local data store. 
		=========================================================================*/
		private void SetCapacity(int capacity) 
 		{
			// Validate that the specified capacity is larger than the current one.
 			if (capacity < m_DataTable.Length)
 			throw new ArgumentException(Environment.GetResourceString("Argument_ALSInvalidCapacity")); 
		
 			// Allocate the new data table. 
			Object[] NewDataTable = new Object[capacity]; 
		
			// Copy all the objects into the new table. 
 			Array.Copy(m_DataTable, NewDataTable, m_DataTable.Length);
		
 			// Save the new table.
 			m_DataTable = NewDataTable; 
		}
 	} 
}

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