Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / SafeMILHandle.cs / 1305600 / SafeMILHandle.cs
//---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: // A safe way to deal with unmanaged MIL interface pointers. //--------------------------------------------------------------------------- using System; using System.Security; using Microsoft.Win32.SafeHandles; using UnsafeNativeMethods = MS.Win32.PresentationCore.UnsafeNativeMethods; namespace System.Windows.Media { internal class SafeMILHandle : SafeHandleZeroOrMinusOneIsInvalid { ////// Use this constructor if the handle isn't ready yet and later /// set the handle with SetHandle. SafeMILHandle owns the release /// of the handle. /// ////// Critical: This derives from a class that has a link demand and inheritance demand /// TreatAsSafe: Ok to call constructor /// [SecurityCritical,SecurityTreatAsSafe] internal SafeMILHandle() : base(true) { } ////// Use this constructor if the handle exists at construction time. /// SafeMILHandle owns the release of the parameter. /// ////// Critical: This derives from a class that has a link demand and inheritance demand /// [SecurityCritical] internal SafeMILHandle(IntPtr handle) : base(true) { SetHandle(handle); } ////// Change our size to the new size specified /// ////// Critical: This code calls into AddMemoryPressure and RemoveMemoryPressure /// both of which have link demands. It is used to keep memory around /// [SecurityCritical] internal void UpdateEstimatedSize(long estimatedSize) { if (_gcPressure != null) { _gcPressure.Release(); } // // estimatedSize may be 0 for small images with fewer than 8 bits per pixel, // attempting to call GC.AddMemoryPressure with a pressure of 0 will cause it to // throw, so don't add memory pressure if estimatedSize is 0. // if (estimatedSize > 0) { _gcPressure = new SafeMILHandleMemoryPressure(estimatedSize); _gcPressure.AddRef(); } } internal void CopyMemoryPressure(SafeMILHandle original) { _gcPressure = original._gcPressure; if (_gcPressure != null) { _gcPressure.AddRef(); } } ////// Critical - calls unmanaged code, not treat as safe because you must /// validate that handle is a valid COM object. /// [SecurityCritical] protected override bool ReleaseHandle() { UnsafeNativeMethods.MILUnknown.ReleaseInterface(ref handle); if (_gcPressure != null) { _gcPressure.Release(); _gcPressure = null; } return true; } // Estimated size of the unmanaged memory private SafeMILHandleMemoryPressure _gcPressure; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. //---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: // A safe way to deal with unmanaged MIL interface pointers. //--------------------------------------------------------------------------- using System; using System.Security; using Microsoft.Win32.SafeHandles; using UnsafeNativeMethods = MS.Win32.PresentationCore.UnsafeNativeMethods; namespace System.Windows.Media { internal class SafeMILHandle : SafeHandleZeroOrMinusOneIsInvalid { ////// Use this constructor if the handle isn't ready yet and later /// set the handle with SetHandle. SafeMILHandle owns the release /// of the handle. /// ////// Critical: This derives from a class that has a link demand and inheritance demand /// TreatAsSafe: Ok to call constructor /// [SecurityCritical,SecurityTreatAsSafe] internal SafeMILHandle() : base(true) { } ////// Use this constructor if the handle exists at construction time. /// SafeMILHandle owns the release of the parameter. /// ////// Critical: This derives from a class that has a link demand and inheritance demand /// [SecurityCritical] internal SafeMILHandle(IntPtr handle) : base(true) { SetHandle(handle); } ////// Change our size to the new size specified /// ////// Critical: This code calls into AddMemoryPressure and RemoveMemoryPressure /// both of which have link demands. It is used to keep memory around /// [SecurityCritical] internal void UpdateEstimatedSize(long estimatedSize) { if (_gcPressure != null) { _gcPressure.Release(); } // // estimatedSize may be 0 for small images with fewer than 8 bits per pixel, // attempting to call GC.AddMemoryPressure with a pressure of 0 will cause it to // throw, so don't add memory pressure if estimatedSize is 0. // if (estimatedSize > 0) { _gcPressure = new SafeMILHandleMemoryPressure(estimatedSize); _gcPressure.AddRef(); } } internal void CopyMemoryPressure(SafeMILHandle original) { _gcPressure = original._gcPressure; if (_gcPressure != null) { _gcPressure.AddRef(); } } ////// Critical - calls unmanaged code, not treat as safe because you must /// validate that handle is a valid COM object. /// [SecurityCritical] protected override bool ReleaseHandle() { UnsafeNativeMethods.MILUnknown.ReleaseInterface(ref handle); if (_gcPressure != null) { _gcPressure.Release(); _gcPressure = null; } return true; } // Estimated size of the unmanaged memory private SafeMILHandleMemoryPressure _gcPressure; } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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