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
- PolygonHotSpot.cs
- ScriptReference.cs
- ListManagerBindingsCollection.cs
- CompositeDispatchFormatter.cs
- ScrollEventArgs.cs
- SqlDependencyUtils.cs
- cookiecollection.cs
- AppliedDeviceFiltersEditor.cs
- QueryContinueDragEvent.cs
- SecurityToken.cs
- OpenFileDialog.cs
- CodeFieldReferenceExpression.cs
- SqlVersion.cs
- DBConnectionString.cs
- MetabaseSettingsIis7.cs
- JoinTreeNode.cs
- Underline.cs
- ExplicitDiscriminatorMap.cs
- UdpChannelFactory.cs
- DataSourceView.cs
- TheQuery.cs
- LastQueryOperator.cs
- Message.cs
- PartialCachingControl.cs
- InstancePersistence.cs
- CapabilitiesSection.cs
- SortDescription.cs
- DataGridViewTextBoxEditingControl.cs
- NavigationCommands.cs
- Site.cs
- _SpnDictionary.cs
- Directory.cs
- MenuBindingsEditorForm.cs
- NamedPermissionSet.cs
- TripleDES.cs
- LoginUtil.cs
- XmlUnspecifiedAttribute.cs
- FastEncoder.cs
- HttpInputStream.cs
- FixedPageStructure.cs
- Rect3DValueSerializer.cs
- OleDbCommandBuilder.cs
- ListViewItemMouseHoverEvent.cs
- LabelLiteral.cs
- WebErrorHandler.cs
- WebException.cs
- ErrorRuntimeConfig.cs
- DirectoryNotFoundException.cs
- HtmlTableRowCollection.cs
- PropertyEntry.cs
- XmlWrappingWriter.cs
- TableItemPattern.cs
- ApplicationSettingsBase.cs
- RetrieveVirtualItemEventArgs.cs
- FullTextBreakpoint.cs
- ColumnResult.cs
- KeyGesture.cs
- XmlSerializer.cs
- DesignRelation.cs
- ScriptManager.cs
- _LocalDataStoreMgr.cs
- PropertyAccessVisitor.cs
- ConfigXmlAttribute.cs
- MediaContext.cs
- ThreadStateException.cs
- SerialPinChanges.cs
- ConnectionProviderAttribute.cs
- TrackingServices.cs
- xsdvalidator.cs
- Point3DCollection.cs
- WindowsClientCredential.cs
- Encoding.cs
- MessagePropertyDescriptionCollection.cs
- IndexedGlyphRun.cs
- ConfigurationElementCollection.cs
- ContentFileHelper.cs
- DbProviderConfigurationHandler.cs
- RepeatBehaviorConverter.cs
- FileDataSourceCache.cs
- TypeListConverter.cs
- UnauthorizedWebPart.cs
- hwndwrapper.cs
- HtmlWindowCollection.cs
- StrongNamePublicKeyBlob.cs
- UnsafeNativeMethods.cs
- Empty.cs
- ResourceReader.cs
- StyleConverter.cs
- _KerberosClient.cs
- MissingFieldException.cs
- COMException.cs
- DataBoundControl.cs
- NativeRightsManagementAPIsStructures.cs
- SetState.cs
- CopyAction.cs
- SectionXmlInfo.cs
- ProjectedSlot.cs
- StandardToolWindows.cs
- recordstate.cs
- DefaultPrintController.cs