48 lines
1.9 KiB
C#
48 lines
1.9 KiB
C#
//------------------------------------------------------------------------------
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// <copyright file="FileUtil.cs" company="Microsoft">
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// </copyright>
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//------------------------------------------------------------------------------
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namespace System.Configuration {
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using System;
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using System.IO;
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using Microsoft.Win32;
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using System.Runtime.InteropServices;
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static internal class FileUtil {
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const int HRESULT_WIN32_FILE_NOT_FOUND = unchecked((int)0x80070002);
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const int HRESULT_WIN32_PATH_NOT_FOUND = unchecked((int)0x80070003);
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//
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// Use to avoid the perf hit of a Demand when the Demand is not necessary for security.
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//
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// If trueOnError is set, then return true if we cannot confirm that the file does NOT exist.
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//
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internal static bool FileExists(string filename, bool trueOnError) {
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UnsafeNativeMethods.WIN32_FILE_ATTRIBUTE_DATA data;
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bool ok = UnsafeNativeMethods.GetFileAttributesEx(filename, UnsafeNativeMethods.GetFileExInfoStandard, out data);
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if (ok) {
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// The path exists. Return true if it is a file, false if a directory.
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return (data.fileAttributes & (int) FileAttributes.Directory) != (int) FileAttributes.Directory;
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}
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else {
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if (!trueOnError) {
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return false;
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}
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else {
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// Return true if we cannot confirm that the file does NOT exist.
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int hr = Marshal.GetHRForLastWin32Error();
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if (hr == HRESULT_WIN32_FILE_NOT_FOUND || hr == HRESULT_WIN32_PATH_NOT_FOUND) {
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return false;
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}
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else {
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return true;
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}
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}
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}
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}
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}
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}
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