文件操作工具类FileUtility（摘自UABv2.0）
最近一直在研究 Smart Client 的 Smart Update 开发，从 Microsoft Updater Application Block v2.0 里面学到了很多东西，这里不得不佩服 Enterprise Library 的设计，设计模式和 XML 的运用使得 Enterprise Library 的扩展性很强，设计十分优美，是学习 OOP 的好范例。本人看了之后感叹自己写的代码大部分还是面向过程
Enterprise Library 的广告就做到这里了，下面一个操作文件的工具类是从 Microsoft Updater Application Block v2.0 里面原封不动取出来，感觉具有一定的参考价值，希望对大家有帮助。
//============================================================================================================
// Microsoft Updater Application Block for .NET
// http://msdn.microsoft.com/library/en-us/dnbda/html/updater.asp
//
// FileUtility.cs
//
// Contains the implementation of the FileUtility helper class.
//
// For more information see the Updater Application Block Implementation Overview.
//
//============================================================================================================
// Copyright ?Microsoft Corporation. All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//============================================================================================================
using System;
using System.IO;
using System.Runtime.InteropServices;
namespace Microsoft.ApplicationBlocks.Updater.Utilities
{
/// <summary>
/// Indicates how to proceed with the move file operation.
/// </summary>
[Flags]
public enum MoveFileFlag : int
{
/// <summary>
/// Perform a default move funtion.
/// </summary>
None = 0x00000000,
/// <summary>
/// If the target file exists, the move function will replace it.
/// </summary>
ReplaceExisting = 0x00000001,
/// <summary>
/// If the file is to be moved to a different volume,
/// the function simulates the move by using the CopyFile and DeleteFile functions.
/// </summary>
CopyAllowed = 0x00000002,
/// <summary>
/// The system does not move the file until the operating system is restarted.
/// The system moves the file immediately after AUTOCHK is executed, but before
/// creating any paging files. Consequently, this parameter enables the function
/// to delete paging files from previous startups.
/// </summary>
DelayUntilReboot = 0x00000004,
/// <summary>
/// The function does not return until the file has actually been moved on the disk.
/// </summary>
WriteThrough = 0x00000008,
/// <summary>
/// Reserved for future use.
/// </summary>
CreateHardLink = 0x00000010,
/// <summary>
/// The function fails if the source file is a link source, but the file cannot be tracked after the move. This situation can occur if the destination is a volume formatted with the FAT file system.
/// </summary>
FailIfNotTrackable = 0x00000020,
}
/// <summary>
/// Provides certain utilities used by configuration processors, such as correcting file paths.
/// </summary>
public sealed class FileUtility
{
#region Constructor
/// <summary>
/// Default constructor.
/// </summary>
private FileUtility()
{
}
#endregion
#region Public members
/// <summary>
/// Returns whether the path is a UNC path.
/// </summary>
/// <param name="path">The path string.</param>
/// <returns><c>true</c> if the path is a UNC path.</returns>
public static bool IsUncPath( string path )
{
// FIRST, check if this is a URL or a UNC path; do this by attempting to construct uri object from it
Uri url = new Uri( path );
if( url.IsUnc )
{
// it is a unc path, return true
return true;
}
else
{
return false;
}
}
/// <summary>
/// Takes a UNC or URL path, determines which it is (NOT hardened against bad strings, assumes one or the other is present)
/// and returns the path with correct trailing slash: backslash for UNC or
/// slash mark for URL.
/// </summary>
/// <param name="path">The URL or UNC string.</param>
/// <returns>Path with correct terminal slash.</returns>
public static string AppendSlashUrlOrUnc( string path )
{
if( IsUncPath( path ) )
{
// it is a unc path, so decorate the end with a back-slash (to correct misconfigurations, defend against trivial errors)
return AppendTerminalBackslash( path );
}
else
{
// assume URL here
return AppendTerminalForwardSlash( path );
}
}
/// <summary>
/// If not present appends terminal backslash to paths.
/// </summary>
/// <param name="path">A path string; for example, "C:\AppUpdaterClient".</param>
/// <returns>A path string with trailing backslash; for example, "C:\AppUpdaterClient\".</returns>
public static string AppendTerminalBackslash( string path )
{
if( path.IndexOf( Path.DirectorySeparatorChar, path.Length - 1 ) == -1 )
{
return path + Path.DirectorySeparatorChar;
}
else
{
return path;
}
}
/// <summary>
/// Appends a terminal slash mark if there is not already one; returns corrected path.
/// </summary>
/// <param name="path">The path that may be missing a terminal slash mark.</param>
/// <returns>The corrected path with terminal slash mark.</returns>
public static string AppendTerminalForwardSlash( string path )
{
if( path.IndexOf( Path.AltDirectorySeparatorChar, path.Length - 1 ) == -1 )
{
return path + Path.AltDirectorySeparatorChar;
}
else
{
return path;
}
}
/// <summary>
/// Creates a new temporary folder under the system temp folder
/// and returns its full pathname.
/// </summary>
/// <returns>The full temp path string.</returns>
public static string CreateTemporaryFolder()
{
return Path.Combine( Path.GetTempPath(), Path.GetFileNameWithoutExtension( Path.GetTempFileName() ) );
}
/// <summary>
/// Copies files from the source to destination directories. Directory.Move is not
/// suitable here because the downloader may still have the temporary
/// directory locked.
/// </summary>
/// <param name="sourcePath">The source path.</param>
/// <param name="destinationPath">The destination path.</param>
public static void CopyDirectory( string sourcePath, string destinationPath )
{
CopyDirectory( sourcePath, destinationPath, true );
}
/// <summary>
/// Copies files from the source to destination directories. Directory.Move is not
/// suitable here because the downloader may still have the temporary
/// directory locked.
/// </summary>
/// <param name="sourcePath">The source path.</param>
/// <param name="destinationPath">The destination path.</param>
/// <param name="overwrite">Indicates whether the destination files should be overwritten.</param>
public static void CopyDirectory( string sourcePath, string destinationPath, bool overwrite )
{
CopyDirRecurse( sourcePath, destinationPath, destinationPath, overwrite );
}
/// <summary>
/// Move a file from a folder to a new one.
/// </summary>
/// <param name="existingFileName">The original file name.</param>
/// <param name="newFileName">The new file name.</param>
/// <param name="flags">Flags about how to move the files.</param>
/// <returns>indicates whether the file was moved.</returns>
public static bool MoveFile( string existingFileName, string newFileName, MoveFileFlag flags)
{
return MoveFileEx( existingFileName, newFileName, (int)flags );
}
/// <summary>
/// Deletes a folder. If the folder cannot be deleted at the time this method is called,
/// the deletion operation is delayed until the next system boot.
/// </summary>
/// <param name="folderPath">The directory to be removed</param>
public static void DestroyFolder( string folderPath )
{
try
{
if ( Directory.Exists( folderPath) )
{
Directory.Delete( folderPath, true );
}
}
catch( Exception )
{
// If we couldn't remove the files, postpone it to the next system reboot
if ( Directory.Exists( folderPath) )
{
FileUtility.MoveFile(
folderPath,
null,
MoveFileFlag.DelayUntilReboot );
}
}
}
/// <summary>
/// Deletes a file. If the file cannot be deleted at the time this method is called,
/// the deletion operation is delayed until the next system boot.
/// </summary>
/// <param name="filePath">The file to be removed</param>
public static void DestroyFile( string filePath )
{
try
{
if ( File.Exists( filePath ) )
{
File.Delete( filePath );
}
}
catch
{
if ( File.Exists( filePath ) )
{
FileUtility.MoveFile(
filePath,
null,
MoveFileFlag.DelayUntilReboot );
}
}
}
/// <summary>
/// Returns the path to the newer version of the .NET Framework installed on the system.
/// </summary>
/// <returns>A string containig the full path to the newer .Net Framework location</returns>
public static string GetLatestDotNetFrameworkPath()
{
Version latestVersion = null;
string fwkPath = Path.GetFullPath( Path.Combine( Environment.SystemDirectory, @"..\Microsoft.NET\Framework" ) );
foreach(string path in Directory.GetDirectories( fwkPath, "v*" ) )
{
string candidateVersion = Path.GetFileName( path ).TrimStart( 'v' );
try
{
Version curVersion = new Version( candidateVersion );
if ( latestVersion == null || ( latestVersion != null && latestVersion < curVersion ) )
{
latestVersion = curVersion;
}
}
catch {}
}
return Path.Combine( fwkPath, "v" + latestVersion.ToString() );
}
#endregion
#region Private members
/// <summary>
/// API declaration of the Win32 function.
/// </summary>
/// <param name="lpExistingFileName">Existing file path.</param>
/// <param name="lpNewFileName">The file path.</param>
/// <param name="dwFlags">Move file flags.</param>
/// <returns>Whether the file was moved or not.</returns>
[DllImport("KERNEL32.DLL")]
private static extern bool MoveFileEx(
string lpExistingFileName,
string lpNewFileName,
long dwFlags );
/// <summary>
/// Utility function that recursively copies directories and files.
/// Again, we could use Directory.Move but we need to preserve the original.
/// </summary>
/// <param name="sourcePath">The source path to copy.</param>
/// <param name="destinationPath">The destination path to copy to.</param>
/// <param name="originalDestination">The original dstination path.</param>
/// <param name="overwrite">Whether the folders should be copied recursively.</param>
private static void CopyDirRecurse( string sourcePath, string destinationPath, string originalDestination, bool overwrite )
{
// ensure terminal backslash
sourcePath = FileUtility.AppendTerminalBackslash( sourcePath );
destinationPath = FileUtility.AppendTerminalBackslash( destinationPath );
if ( !Directory.Exists( destinationPath ) )
{
Directory.CreateDirectory( destinationPath );
}
// get dir info which may be file or dir info object
DirectoryInfo dirInfo = new DirectoryInfo( sourcePath );
string destFileName = null;
foreach( FileSystemInfo fsi in dirInfo.GetFileSystemInfos() )
{
if ( fsi is FileInfo )
{
destFileName = Path.Combine( destinationPath, fsi.Name );
// if file object just copy when overwrite is allowed
if ( File.Exists( destFileName ) )
{
if ( overwrite )
{
File.Copy( fsi.FullName, destFileName, true );
}
}
else
{
File.Copy( fsi.FullName, destFileName );
}
}
else
{
// avoid this recursion path, otherwise copying directories as child directories
// would be an endless recursion (up to an stack-overflow exception).
if ( fsi.FullName != originalDestination )
{
// must be a directory, create destination sub-folder and recurse to copy files
//Directory.CreateDirectory( destinationPath + fsi.Name );
CopyDirRecurse( fsi.FullName, destinationPath + fsi.Name, originalDestination, overwrite );
}
}
}
}
#endregion
}
}
