Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / Util / FileEnumerator.cs / 1 / FileEnumerator.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- /* * FileEnumerator class * * Copyright (c) 2003 Microsoft Corporation * * Class to efficiently enumerate the files in a directory. The only thing the framework provides * to do this is Directory.GetFiles(), which is unusable on large directories because it returns an * array containing all the file names at once (huge memory allocation). * * An efficient alternative is to use FindFirstFile/FindNextFile, which works but requires a lot * more code. Also, it makes our code base harder to port to non-windows platforms. * * This FileEnumerator class solves both problem, by providing a simple and efficient wrapper. * By working with a single object, it is almost as efficient as calling FindFirstFile/FindNextFile, * but is much easier to use. e.g. instead of: * * UnsafeNativeMethods.WIN32_FIND_DATA wfd; * IntPtr hFindFile = UnsafeNativeMethods.FindFirstFile(physicalDir + @"\*.*", out wfd); * * if (hFindFile == INVALID_HANDLE_VALUE) * return; * * try { * for (bool more=true; more; more=UnsafeNativeMethods.FindNextFile(hFindFile, out wfd)) { * * // Skip false directories * if (wfd.cFileName == "." || wfd.cFileName == "..") * continue; * * string fullPath = Path.Combine(physicalDir, wfd.cFileName); * * ProcessFile(fullPath); * } * } * finally { * UnsafeNativeMethods.FindClose(hFindFile); * } * * we can simply write * * foreach (FileData fileData in FileEnumerator.Create(physicalDir)) { * ProcessFile(fileData.FullName); * } */ namespace System.Web.Util { using System.IO; using System.Collections; /* * This is a somewhat artificial base class for FileEnumerator. The main reason * for it is to allow user code to be more readable, by looking like: * foreach (FileData fileData in FileEnumerator.Create(path)) { ... } * instead of * foreach (FileEnumerator fileData in FileEnumerator.Create(path)) { ... } */ internal abstract class FileData { protected string _path; protected UnsafeNativeMethods.WIN32_FIND_DATA _wfd; internal string Name { get { return _wfd.cFileName; } } internal string FullName { get { return _path + @"\" + _wfd.cFileName; } } internal bool IsDirectory { get { return (_wfd.dwFileAttributes & UnsafeNativeMethods.FILE_ATTRIBUTE_DIRECTORY) != 0; } } internal bool IsHidden { get { return (_wfd.dwFileAttributes & UnsafeNativeMethods.FILE_ATTRIBUTE_HIDDEN) != 0; } } internal FindFileData GetFindFileData() { return new FindFileData(ref _wfd); } } internal class FileEnumerator: FileData, IEnumerable, IEnumerator, IDisposable { private IntPtr _hFindFile = UnsafeNativeMethods.INVALID_HANDLE_VALUE; internal static FileEnumerator Create(string path) { return new FileEnumerator(path); } private FileEnumerator(string path) { _path = Path.GetFullPath(path); } ~FileEnumerator() { ((IDisposable)this).Dispose(); } // Should the current file be excluded from the enumeration private bool SkipCurrent() { // Skip false directories if (_wfd.cFileName == "." || _wfd.cFileName == "..") return true; return false; } // We just return ourselves for the enumerator, to avoid creating a new object IEnumerator IEnumerable.GetEnumerator() { return this; } bool IEnumerator.MoveNext() { for (;;) { if (_hFindFile == UnsafeNativeMethods.INVALID_HANDLE_VALUE) { _hFindFile = UnsafeNativeMethods.FindFirstFile(_path + @"\*.*", out _wfd); // Empty enumeration case if (_hFindFile == UnsafeNativeMethods.INVALID_HANDLE_VALUE) return false; } else { bool hasMoreFiles = UnsafeNativeMethods.FindNextFile(_hFindFile, out _wfd); if (!hasMoreFiles) return false; } if (!SkipCurrent()) return true; } } // The current object of the enumeration is always ourselves. No new object created. object IEnumerator.Current { get { return this; } } void IEnumerator.Reset() { // We don't support reset, though it would be easy to add if needed throw new InvalidOperationException(); } void IDisposable.Dispose() { if (_hFindFile != UnsafeNativeMethods.INVALID_HANDLE_VALUE) { UnsafeNativeMethods.FindClose(_hFindFile); _hFindFile = UnsafeNativeMethods.INVALID_HANDLE_VALUE; } System.GC.SuppressFinalize(this); } } }
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- RayHitTestParameters.cs
- milexports.cs
- RecipientInfo.cs
- KeyValueSerializer.cs
- SoapInteropTypes.cs
- DeviceFiltersSection.cs
- MsmqAppDomainProtocolHandler.cs
- QueryableDataSource.cs
- MouseGesture.cs
- NetPeerTcpBindingElement.cs
- _LocalDataStore.cs
- NumericExpr.cs
- FixedDocument.cs
- SqlNotificationEventArgs.cs
- HttpRuntime.cs
- TemplateControlBuildProvider.cs
- CodeCatchClause.cs
- recordstatefactory.cs
- OutOfMemoryException.cs
- CompositeCollectionView.cs
- DateTimeFormatInfo.cs
- EngineSite.cs
- GacUtil.cs
- PropertyValidationContext.cs
- PrintController.cs
- ProbeDuplexCD1AsyncResult.cs
- ListViewItemMouseHoverEvent.cs
- HostingPreferredMapPath.cs
- TagNameToTypeMapper.cs
- ProtocolsConfigurationEntry.cs
- XhtmlBasicLiteralTextAdapter.cs
- XmlSchemaExternal.cs
- SessionStateItemCollection.cs
- AuthenticationException.cs
- FormViewDeleteEventArgs.cs
- UpdatePanelTriggerCollection.cs
- _LoggingObject.cs
- XmlAttributes.cs
- WorkflowMarkupSerializationManager.cs
- DeleteBookmarkScope.cs
- CompressStream.cs
- CodeTypeDeclarationCollection.cs
- DataMisalignedException.cs
- IsolatedStorage.cs
- SpellerError.cs
- KeyboardDevice.cs
- XmlAttributeCollection.cs
- GiveFeedbackEventArgs.cs
- SegmentInfo.cs
- XmlEnumAttribute.cs
- PropertyEntry.cs
- x509store.cs
- VisualStyleElement.cs
- BulletedList.cs
- AssemblyCacheEntry.cs
- EntityDesignerDataSourceView.cs
- ScrollEvent.cs
- WebPartUserCapability.cs
- XamlPoint3DCollectionSerializer.cs
- RenderContext.cs
- XmlReaderSettings.cs
- SqlMethodTransformer.cs
- RichTextBox.cs
- GenericEnumerator.cs
- ScaleTransform3D.cs
- RenamedEventArgs.cs
- TextControl.cs
- PreviewPageInfo.cs
- OdbcException.cs
- EmbossBitmapEffect.cs
- MessageQueue.cs
- NamespaceCollection.cs
- TimeSpanOrInfiniteConverter.cs
- Visual3DCollection.cs
- URIFormatException.cs
- RadioButtonAutomationPeer.cs
- TableRow.cs
- KnownTypesHelper.cs
- LinkArea.cs
- TextPenaltyModule.cs
- SmiRecordBuffer.cs
- DBProviderConfigurationHandler.cs
- XmlObjectSerializer.cs
- Expressions.cs
- Main.cs
- Polyline.cs
- CombinedGeometry.cs
- XmlSchemaImporter.cs
- TrustSection.cs
- PngBitmapDecoder.cs
- ConnectionsZoneDesigner.cs
- SmiConnection.cs
- RuntimeHelpers.cs
- UserPreferenceChangedEventArgs.cs
- CacheMode.cs
- Math.cs
- AvTraceDetails.cs
- WindowInteractionStateTracker.cs
- MessageOperationFormatter.cs
- ProfileEventArgs.cs