Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Globalization / AgileSafeNativeMemoryHandle.cs / 1 / AgileSafeNativeMemoryHandle.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== /*============================================================ ** ** Class: AgileSafeNativeMemoryHandle ** ** This class is to hold native memory handle and make sure it ** gets released when the object get collected by GC. ** ** This class can hold one of two types of memory handle ** first it can hold a handle for memory created using ** Marshal.AllocHGlobal. this can happen when creating ** the object using constructor taking IntPtr as handle. ** in this case mode = false. ** ** second it can hold handle for memory created from mapped ** file. this can happen when creating the object using the ** file name then the constructor will open and map this file ** and hold the mapped memory section handle ** in this case mode = true. ** ** IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT IMPORTANT ** this class is used only with CultureInfo or its ** field classes. ** this class is special case that is agile and has finalizer ** and it is a special case like Thread class. ** this class is agile to make sure it survive the app domain ** unloading. otherwise we can get AV when culture info cross ** the app domain boundary. ** so don't use it in any other purpose. ** ===========================================================*/ using System; using System.IO; using System.Security; using System.Security.Permissions; using System.Runtime.InteropServices; using System.Runtime.CompilerServices; using System.Runtime.ConstrainedExecution; using Microsoft.Win32; using Microsoft.Win32.SafeHandles; using System.Runtime.Versioning; namespace System.Globalization { internal sealed class AgileSafeNativeMemoryHandle : SafeHandleZeroOrMinusOneIsInvalid { private const int PAGE_READONLY = 0x02; private const int SECTION_MAP_READ = 0x0004; private unsafe byte* bytes; // // The only handle we keep it open is the mapped memory section and we close // both the stream and mapped file handle as the OS keep the memory section // mapped even when closing the files. // The benefit for closing the file and stream handle is have flexability // to rename the file while it is in use. // private long fileSize = 0; // mode is true if the memory created from mapped file. // and false if the memory created from Marshal.AllocHGlobal. private bool mode = false; [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode=true)] internal AgileSafeNativeMemoryHandle() : base(true) {} [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode=true)] internal AgileSafeNativeMemoryHandle(IntPtr handle, bool ownsHandle) : base (ownsHandle) { SetHandle(handle); } [ResourceExposure(ResourceScope.Machine)] [ResourceConsumption(ResourceScope.Machine)] internal unsafe AgileSafeNativeMemoryHandle(String fileName) : this(fileName, null) {} [ResourceExposure(ResourceScope.Machine)] [ResourceConsumption(ResourceScope.Machine)] internal unsafe AgileSafeNativeMemoryHandle(String fileName, String fileMappingName) : base(true) { mode = true; // // Use native API to create the file directly. // SafeFileHandle fileHandle = Win32Native.UnsafeCreateFile(fileName, FileStream.GENERIC_READ, FileShare.Read, null, FileMode.Open, 0, IntPtr.Zero); int lastError = Marshal.GetLastWin32Error(); if (fileHandle.IsInvalid) { BCLDebug.Assert(false, "Failed to create file " + fileName + ", GetLastError = " + lastError); throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidOperation_UnexpectedWin32Error"), lastError)); } int highSize; int lowSize = Win32Native.GetFileSize(fileHandle, out highSize); if (lowSize == Win32Native.INVALID_FILE_SIZE) { fileHandle.Close(); BCLDebug.Assert(false, "Failed to get the file size of " + fileName + ", GetLastError = " + lastError); throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidOperation_UnexpectedWin32Error"), lastError)); } fileSize = (((long) highSize) << 32) | ((uint) lowSize); if (fileSize == 0) { // we cannot map zero size file. the caller should check for the file size. fileHandle.Close(); return; } SafeFileMappingHandle fileMapHandle = Win32Native.CreateFileMapping(fileHandle, IntPtr.Zero, PAGE_READONLY, 0, 0, fileMappingName); lastError = Marshal.GetLastWin32Error(); fileHandle.Close(); if (fileMapHandle.IsInvalid) { BCLDebug.Assert(false, "Failed to create file mapping for file " + fileName + ", GetLastError = " + lastError); throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidOperation_UnexpectedWin32Error"), lastError)); } // Use a CER to ensure that we store the handle within this SafeHandle without allowing async exceptions. RuntimeHelpers.PrepareConstrainedRegions(); try { } finally { handle = Win32Native.MapViewOfFile(fileMapHandle, SECTION_MAP_READ, 0, 0, UIntPtr.Zero); } lastError = Marshal.GetLastWin32Error(); if (handle == IntPtr.Zero) { fileMapHandle.Close(); BCLDebug.Assert(false, "Failed to map a view of file " + fileName + ", GetLastError = " + lastError); throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("InvalidOperation_UnexpectedWin32Error"), lastError)); } bytes = (byte*) this.DangerousGetHandle(); fileMapHandle.Close(); } internal long FileSize { get { BCLDebug.Assert(mode == true, "The memory is not created from mapped file to request the size"); return fileSize; } } internal unsafe byte* GetBytePtr() { BCLDebug.Assert(bytes != null && mode == true, "bytes can requested only if the memory created from mapped file"); return (bytes); } override protected bool ReleaseHandle() { if (!IsInvalid) { if (mode == true) { if (Win32Native.UnmapViewOfFile(handle)) { handle = IntPtr.Zero; return true; } } else { Marshal.FreeHGlobal(handle); handle = IntPtr.Zero; return true; } } return false; } } }
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- DefaultParameterValueAttribute.cs
- DtdParser.cs
- RuntimeVariableList.cs
- ObjectTypeMapping.cs
- Funcletizer.cs
- XPathNavigatorKeyComparer.cs
- DataSourceHelper.cs
- SQLResource.cs
- AdCreatedEventArgs.cs
- Match.cs
- OutputCacheSection.cs
- Size.cs
- XMLUtil.cs
- VectorAnimation.cs
- TextEditorCopyPaste.cs
- XmlElementCollection.cs
- EntityCommand.cs
- HandlerBase.cs
- RangeValuePattern.cs
- RunClient.cs
- IntSecurity.cs
- PersonalizableTypeEntry.cs
- ZipPackage.cs
- DataColumnChangeEvent.cs
- ExpressionBindingCollection.cs
- Error.cs
- DigestTraceRecordHelper.cs
- SHA384Managed.cs
- MaskDescriptor.cs
- SqlProviderServices.cs
- InstanceDataCollection.cs
- MdiWindowListStrip.cs
- FeatureManager.cs
- ToolStripButton.cs
- OdbcFactory.cs
- ITextView.cs
- EntityTypeBase.cs
- SQLDouble.cs
- ResourceManager.cs
- glyphs.cs
- XmlTypeMapping.cs
- WebPartConnectionsCancelVerb.cs
- SqlOuterApplyReducer.cs
- HashSetDebugView.cs
- StringBlob.cs
- GlobalItem.cs
- CodeAccessSecurityEngine.cs
- SQLMembershipProvider.cs
- DispatcherEventArgs.cs
- SqlUserDefinedAggregateAttribute.cs
- FlowDocument.cs
- RoutedEventArgs.cs
- TextTreeInsertUndoUnit.cs
- SoapSchemaExporter.cs
- WindowsBrush.cs
- Misc.cs
- ViewValidator.cs
- DetailsViewCommandEventArgs.cs
- CombinedGeometry.cs
- GenericPrincipal.cs
- TypeSystem.cs
- BaseTreeIterator.cs
- COM2ExtendedTypeConverter.cs
- DependencyProperty.cs
- CodePrimitiveExpression.cs
- WSHttpTransportSecurityElement.cs
- ThreadInterruptedException.cs
- AstNode.cs
- Queue.cs
- RestHandler.cs
- TreeViewImageIndexConverter.cs
- AssociationSet.cs
- TextDecorationCollection.cs
- TimeSpanSecondsOrInfiniteConverter.cs
- InvokePattern.cs
- SQLDouble.cs
- CatalogZone.cs
- DbConnectionStringBuilder.cs
- MetadataCache.cs
- AttributeAction.cs
- FilteredDataSetHelper.cs
- ClosableStream.cs
- securitycriticaldata.cs
- NameObjectCollectionBase.cs
- HealthMonitoringSection.cs
- BaseProcessor.cs
- ReferentialConstraint.cs
- CapabilitiesPattern.cs
- FormViewDeletedEventArgs.cs
- XslException.cs
- ProviderConnectionPoint.cs
- BasicExpandProvider.cs
- versioninfo.cs
- CngUIPolicy.cs
- ColorTranslator.cs
- EntitySqlQueryState.cs
- ParameterElementCollection.cs
- CompiledQuery.cs
- BamlLocalizerErrorNotifyEventArgs.cs
- NumberFunctions.cs