Code:
/ FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / 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); } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- TextBoxLine.cs
- COM2EnumConverter.cs
- TemplateKey.cs
- XmlNodeChangedEventArgs.cs
- InternalBufferOverflowException.cs
- GroupBoxRenderer.cs
- ItemContainerGenerator.cs
- XPathMultyIterator.cs
- TableAutomationPeer.cs
- AnimationClockResource.cs
- Variant.cs
- PrimitiveSchema.cs
- XmlDictionary.cs
- DelegateTypeInfo.cs
- SecurityPolicySection.cs
- OleDbException.cs
- FlowDocumentScrollViewerAutomationPeer.cs
- SoapSchemaMember.cs
- SQLInt32Storage.cs
- PLINQETWProvider.cs
- MbpInfo.cs
- LinqDataSourceUpdateEventArgs.cs
- ListViewSortEventArgs.cs
- InstanceOwner.cs
- RedBlackList.cs
- ExtensionDataObject.cs
- EntitySqlQueryBuilder.cs
- EntityClassGenerator.cs
- ReferencedAssembly.cs
- ParserContext.cs
- x509utils.cs
- SafeEventLogWriteHandle.cs
- ScriptDescriptor.cs
- EditorPartChrome.cs
- ResizeGrip.cs
- XmlStringTable.cs
- NetworkInformationException.cs
- ServicePoint.cs
- CodeMemberEvent.cs
- ComplusEndpointConfigContainer.cs
- DataServiceCollectionOfT.cs
- ClockGroup.cs
- BrowserCapabilitiesFactory.cs
- SqlDeflator.cs
- IndexedEnumerable.cs
- AttachedProperty.cs
- XmlSchemaValidationException.cs
- DataGridViewRowsRemovedEventArgs.cs
- CachedTypeface.cs
- PropertyStore.cs
- XmlSchemaImporter.cs
- DataGridRelationshipRow.cs
- FloatUtil.cs
- ConfigXmlWhitespace.cs
- SafeFileHandle.cs
- SamlSubject.cs
- ExpandableObjectConverter.cs
- Certificate.cs
- DocumentXPathNavigator.cs
- InternalEnumValidator.cs
- WorkflowApplicationAbortedException.cs
- SolidBrush.cs
- FileDialog.cs
- BindingValueChangedEventArgs.cs
- TimerEventSubscriptionCollection.cs
- HandledMouseEvent.cs
- RuntimeConfigLKG.cs
- ArraySubsetEnumerator.cs
- XmlDocumentFragment.cs
- AQNBuilder.cs
- PrimitiveRenderer.cs
- MarkupObject.cs
- ClipboardData.cs
- Size3D.cs
- QilParameter.cs
- XPathItem.cs
- ResourcePermissionBaseEntry.cs
- AssemblyFilter.cs
- WindowExtensionMethods.cs
- _NativeSSPI.cs
- MenuBindingsEditorForm.cs
- FtpWebResponse.cs
- DataSourceControlBuilder.cs
- ContainerVisual.cs
- WaitHandle.cs
- ToolStripPanelRow.cs
- ServiceContractGenerator.cs
- LicFileLicenseProvider.cs
- TagMapCollection.cs
- WmfPlaceableFileHeader.cs
- AutoResetEvent.cs
- ToolStripRendererSwitcher.cs
- TraceSection.cs
- SerializationEventsCache.cs
- MexServiceChannelBuilder.cs
- TextStore.cs
- Buffer.cs
- ThicknessAnimation.cs
- Interop.cs
- AutomationEvent.cs