.net 如何从绝对路径得到相对路径
“我的应用”中有一个部分显示用户通过OpenFileDialog加载的文件路径。它占用了太多的空间来显示整个路径，但我不想只显示文件名，因为它可能不明确。因此，我更愿意显示相对于assembly/exe目录的文件路径 例如，程序集位于.net 如何从绝对路径得到相对路径,.net,.net,“我的应用”中有一个部分显示用户通过OpenFileDialog加载的文件路径。它占用了太多的空间来显示整个路径，但我不想只显示文件名，因为它可能不明确。因此，我更愿意显示相对于assembly/exe目录的文件路径 例如，程序集位于C:\Program Files\Dummy Folder\MyProgram处，文件位于C:\Program Files\Dummy Folder\MyProgram\Data\datafile1.dat处，然后我希望它显示\Data\datafile1.dat。
C:\Program Files\Dummy Folder\MyProgramC:\Program Files\Dummy Folder\MyProgram\Data\datafile1.dat\Data\datafile1.datC:\Program Files\Dummy Folder\datafile1.dat。\datafile1.datRelPath = AbsPath.Replace(ApplicationPath, ".")
我会在目录级别拆分你的两条路径。从那里，找到分歧点并返回到程序集文件夹，每次通过目录时都在“../”前面加上前缀
但是请记住，绝对路径无处不在，通常比相对路径更容易阅读。我个人不会向用户显示相对路径，除非这是绝对必要的。我会在目录级别拆分两条路径。从那里，找到分歧点并返回到程序集文件夹，每次通过目录时都在“../”前面加上前缀 但是请记住，绝对路径无处不在，通常比相对路径更容易阅读。我个人不会向用户显示相对路径，除非它是绝对必要的。shlwapi.dll中有一个Win32（C++）函数，它可以完全满足您的要求： 但是，我不知道从.NET访问此文件的任何方法，只能通过p/调用它。shlwapi.dll中有一个Win32（C++）函数，它完全满足您的要求：
但是，除了p/调用它之外，我不知道从.NET访问它的任何方法。正如Alex Brault指出的那样，特别是在Windows上，绝对路径（包括驱动器号和全部）是明确的，而且通常更好 OpenFileDialog不应该使用常规的树浏览器结构吗 为了获得适当的命名，RefDir是要指定路径的相对目录；AbsName是要映射的绝对路径名；而RelPath是得到的相对路径 选择以下匹配的第一个选项：
- 如果驱动器号不同，则从RefDir到AbsName之间没有相对路径；您必须使用该名称
- 如果AbsName位于RefDir的子目录中或是RefDir中的文件，则只需从AbsName的开头删除RefDir即可创建RelPath；可以选择在“/”（或“\”之前加前缀，因为您在Windows上）
- 查找RefDir和AbsName的最长公共前缀（其中D:\Abc\Def和D:\Abc\Default共享D:\Abc作为最长公共前缀；它必须是名称组件的映射，而不是简单的最长公共子字符串）；称之为LCP。从AbsName和RefDir中删除LCP。对于（RefDir-LCP）中剩余的每个路径组件，在“.\”之前加上（AbsName-LCP）以生成RelPath
RefDir = D:\Abc\Def\Ghi
AbsName = D:\Abc\Default\Karma\Crucible
除了Unix系统不支持驱动器号（因此所有内容都始终位于同一根目录下，因此第一个项目符号不相关）之外，在Unix上也可以使用相同的技术。正如Alex Brault指出的，特别是在Windows上，绝对路径（包含驱动器号和全部）是明确的，而且通常更好 OpenFileDialog不应该使用常规的树浏览器结构吗 为了获得适当的命名，RefDir是要指定路径的相对目录；AbsName是要映射的绝对路径名；而RelPath是得到的相对路径 选择以下匹配的第一个选项：
- 如果驱动器号不同，则从RefDir到AbsName之间没有相对路径；您必须使用该名称
- 如果AbsName位于RefDir的子目录中或是RefDir中的文件，则只需从AbsName的开头删除RefDir即可创建RelPath；可以选择在“/”（或“\”之前加前缀，因为您在Windows上）
- 查找RefDir和AbsName的最长公共前缀（其中D:\Abc\Def和D:\Abc\Default共享D:\Abc作为最长公共前缀；它必须是名称组件的映射，而不是简单的最长公共子字符串）；称之为LCP。从AbsName和RefDir中删除LCP。对于（RefDir-LCP）中剩余的每个路径组件，在“.\”之前加上（AbsName-LCP）以生成RelPath
LCP = D:\Abc
(RefDir - LCP) = Def\Ghi
(Absname - LCP) = Default\Karma\Crucible
RelPath = ..\..\Default\Karma\Crucible
/// <summary>
/// Creates a relative path from one file
/// or folder to another.
/// </summary>
/// <param name="fromDirectory">
/// Contains the directory that defines the
/// start of the relative path.
/// </param>
/// <param name="toPath">
/// Contains the path that defines the
/// endpoint of the relative path.
/// </param>
/// <returns>
/// The relative path from the start
/// directory to the end path.
/// </returns>
/// <exception cref="ArgumentNullException"></exception>
public static string MakeRelative(string fromDirectory, string toPath)
{
if (fromDirectory == null)
throw new ArgumentNullException("fromDirectory");
if (toPath == null)
throw new ArgumentNullException("toPath");
bool isRooted = (Path.IsPathRooted(fromDirectory) && Path.IsPathRooted(toPath));
if (isRooted)
{
bool isDifferentRoot = (string.Compare(Path.GetPathRoot(fromDirectory), Path.GetPathRoot(toPath), true) != 0);
if (isDifferentRoot)
return toPath;
}
List<string> relativePath = new List<string>();
string[] fromDirectories = fromDirectory.Split(Path.DirectorySeparatorChar);
string[] toDirectories = toPath.Split(Path.DirectorySeparatorChar);
int length = Math.Min(fromDirectories.Length, toDirectories.Length);
int lastCommonRoot = -1;
// find common root
for (int x = 0; x < length; x++)
{
if (string.Compare(fromDirectories[x], toDirectories[x], true) != 0)
break;
lastCommonRoot = x;
}
if (lastCommonRoot == -1)
return toPath;
// add relative folders in from path
for (int x = lastCommonRoot + 1; x < fromDirectories.Length; x++)
{
if (fromDirectories[x].Length > 0)
relativePath.Add("..");
}
// add to folders to path
for (int x = lastCommonRoot + 1; x < toDirectories.Length; x++)
{
relativePath.Add(toDirectories[x]);
}
// create relative path
string[] relativeParts = new string[relativePath.Count];
relativePath.CopyTo(relativeParts, 0);
string newPath = string.Join(Path.DirectorySeparatorChar.ToString(), relativeParts);
return newPath;
}
/// <summary>
/// Creates a relative path from one file or folder to another.
/// </summary>
/// <param name="fromPath">Contains the directory that defines the start of the relative path.</param>
/// <param name="toPath">Contains the path that defines the endpoint of the relative path.</param>
/// <returns>The relative path from the start directory to the end path or <c>toPath</c> if the paths are not related.</returns>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="UriFormatException"></exception>
/// <exception cref="InvalidOperationException"></exception>
public static String MakeRelativePath(String fromPath, String toPath)
{
if (String.IsNullOrEmpty(fromPath)) throw new ArgumentNullException("fromPath");
if (String.IsNullOrEmpty(toPath)) throw new ArgumentNullException("toPath");
Uri fromUri = new Uri(fromPath);
Uri toUri = new Uri(toPath);
if (fromUri.Scheme != toUri.Scheme) { return toPath; } // path can't be made relative.
Uri relativeUri = fromUri.MakeRelativeUri(toUri);
String relativePath = Uri.UnescapeDataString(relativeUri.ToString());
if (toUri.Scheme.Equals("file", StringComparison.InvariantCultureIgnoreCase))
{
relativePath = relativePath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
}
return relativePath;
}
public static string GetRelativePath(string fromPath, string toPath)
{
int fromAttr = GetPathAttribute(fromPath);
int toAttr = GetPathAttribute(toPath);
StringBuilder path = new StringBuilder(260); // MAX_PATH
if(PathRelativePathTo(
path,
fromPath,
fromAttr,
toPath,
toAttr) == 0)
{
throw new ArgumentException("Paths must have a common prefix");
}
return path.ToString();
}
private static int GetPathAttribute(string path)
{
DirectoryInfo di = new DirectoryInfo(path);
if (di.Exists)
{
return FILE_ATTRIBUTE_DIRECTORY;
}
FileInfo fi = new FileInfo(path);
if(fi.Exists)
{
return FILE_ATTRIBUTE_NORMAL;
}
throw new FileNotFoundException();
}
private const int FILE_ATTRIBUTE_DIRECTORY = 0x10;
private const int FILE_ATTRIBUTE_NORMAL = 0x80;
[DllImport("shlwapi.dll", SetLastError = true)]
private static extern int PathRelativePathTo(StringBuilder pszPath,
string pszFrom, int dwAttrFrom, string pszTo, int dwAttrTo);
public static string MakeRelativePath(string fromPath, string toPath)
{
// use Path.GetFullPath to canonicalise the paths (deal with multiple directory seperators, etc)
return Path.GetFullPath(toPath).Substring(Path.GetFullPath(fromPath).Length + 1);
}
public static string GetRelativePath(string BasePath, string AbsolutePath)
{
char Separator = Path.DirectorySeparatorChar;
if (string.IsNullOrWhiteSpace(BasePath)) BasePath = Directory.GetCurrentDirectory();
var ReturnPath = "";
var CommonPart = "";
var BasePathFolders = BasePath.Split(Separator);
var AbsolutePathFolders = AbsolutePath.Split(Separator);
var i = 0;
while (i < BasePathFolders.Length & i < AbsolutePathFolders.Length)
{
if (BasePathFolders[i].ToLower() == AbsolutePathFolders[i].ToLower())
{
CommonPart += BasePathFolders[i] + Separator;
}
else
{
break;
}
i += 1;
}
if (CommonPart.Length > 0)
{
var parents = BasePath.Substring(CommonPart.Length - 1).Split(Separator);
foreach (var ParentDir in parents)
{
if (!string.IsNullOrEmpty(ParentDir))
ReturnPath += ".." + Separator;
}
}
ReturnPath += AbsolutePath.Substring(CommonPart.Length);
return ReturnPath;
}
public static class StringExtensions
{
/// <summary>
/// Creates a relative path from one file or folder to another.
/// </summary>
/// <param name="absPath">Absolute path.</param>
/// <param name="relTo">Directory that defines the start of the relative path.</param>
/// <returns>The relative path from the start directory to the end path.</returns>
public static string MakeRelativePath(this string absPath, string relTo)
{
string[] absParts = absPath.Split(Path.DirectorySeparatorChar);
string[] relParts = relTo.Split(Path.DirectorySeparatorChar);
// Get the shortest of the two paths
int len = absParts.Length < relParts.Length
? absParts.Length : relParts.Length;
// Use to determine where in the loop we exited
int lastCommonRoot = -1;
int index;
// Find common root
for (index = 0; index < len; index++)
{
if (absParts[index].Equals(relParts[index], StringComparison.OrdinalIgnoreCase))
lastCommonRoot = index;
else
break;
}
// If we didn't find a common prefix then throw
if (lastCommonRoot == -1)
throw new ArgumentException("The path of the two files doesn't have any common base.");
// Build up the relative path
var relativePath = new StringBuilder();
// Add on the ..
for (index = lastCommonRoot + 1; index < relParts.Length; index++)
{
relativePath.Append("..");
relativePath.Append(Path.DirectorySeparatorChar);
}
// Add on the folders
for (index = lastCommonRoot + 1; index < absParts.Length - 1; index++)
{
relativePath.Append(absParts[index]);
relativePath.Append(Path.DirectorySeparatorChar);
}
relativePath.Append(absParts[absParts.Length - 1]);
return relativePath.ToString();
}
}
var relativePath = Path.GetRelativePath(
@"C:\Program Files\Dummy Folder\MyProgram",
@"C:\Program Files\Dummy Folder\MyProgram\Data\datafile1.dat");
/// <summary>
/// Creates a relative path from one file or folder to another.
/// </summary>
/// <param name="fromPath">Contains the directory that defines the start of the relative path.</param>
/// <param name="toPath">Contains the path that defines the endpoint of the relative path.</param>
/// <returns>The relative path from the start directory to the end path.</returns>
/// <exception cref="ArgumentNullException"><paramref name="fromPath"/> or <paramref name="toPath"/> is <c>null</c>.</exception>
/// <exception cref="UriFormatException"></exception>
/// <exception cref="InvalidOperationException"></exception>
public static string GetRelativePath(string fromPath, string toPath)
{
if (string.IsNullOrEmpty(fromPath))
{
throw new ArgumentNullException("fromPath");
}
if (string.IsNullOrEmpty(toPath))
{
throw new ArgumentNullException("toPath");
}
Uri fromUri = new Uri(AppendDirectorySeparatorChar(fromPath));
Uri toUri = new Uri(AppendDirectorySeparatorChar(toPath));
if (fromUri.Scheme != toUri.Scheme)
{
return toPath;
}
Uri relativeUri = fromUri.MakeRelativeUri(toUri);
string relativePath = Uri.UnescapeDataString(relativeUri.ToString());
if (string.Equals(toUri.Scheme, Uri.UriSchemeFile, StringComparison.OrdinalIgnoreCase))
{
relativePath = relativePath.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
}
return relativePath;
}
private static string AppendDirectorySeparatorChar(string path)
{
// Append a slash only if the path is a directory and does not have a slash.
if (!Path.HasExtension(path) &&
!path.EndsWith(Path.DirectorySeparatorChar.ToString()))
{
return path + Path.DirectorySeparatorChar;
}
return path;
}
var relativePath = PathExtended.GetRelativePath(
@"C:\Program Files\Dummy Folder\MyProgram",
@"C:\Program Files\Dummy Folder\MyProgram\Data\datafile1.dat");
public static class PathExtended
{
private const int FILE_ATTRIBUTE_DIRECTORY = 0x10;
private const int FILE_ATTRIBUTE_NORMAL = 0x80;
private const int MaximumPath = 260;
public static string GetRelativePath(string fromPath, string toPath)
{
var fromAttribute = GetPathAttribute(fromPath);
var toAttribute = GetPathAttribute(toPath);
var stringBuilder = new StringBuilder(MaximumPath);
if (PathRelativePathTo(
stringBuilder,
fromPath,
fromAttribute,
toPath,
toAttribute) == 0)
{
throw new ArgumentException("Paths must have a common prefix.");
}
return stringBuilder.ToString();
}
private static int GetPathAttribute(string path)
{
var directory = new DirectoryInfo(path);
if (directory.Exists)
{
return FILE_ATTRIBUTE_DIRECTORY;
}
var file = new FileInfo(path);
if (file.Exists)
{
return FILE_ATTRIBUTE_NORMAL;
}
throw new FileNotFoundException(
"A file or directory with the specified path was not found.",
path);
}
[DllImport("shlwapi.dll", SetLastError = true)]
private static extern int PathRelativePathTo(
StringBuilder pszPath,
string pszFrom,
int dwAttrFrom,
string pszTo,
int dwAttrTo);
}
public static string ToRelativePath(string filePath, string refPath)
{
var pathNormalized = Path.GetFullPath(filePath);
var refNormalized = Path.GetFullPath(refPath);
refNormalized = refNormalized.TrimEnd('\\', '/');
if (!pathNormalized.StartsWith(refNormalized))
throw new ArgumentException();
var res = pathNormalized.Substring(refNormalized.Length + 1);
return res;
}
private string rel(string path) {
string[] cwd = new Regex(@"[\\]").Split(Directory.GetCurrentDirectory());
string[] fp = new Regex(@"[\\]").Split(path);
int common = 0;
for (int n = 0; n < fp.Length; n++) {
if (n < cwd.Length && n < fp.Length && cwd[n] == fp[n]) {
common++;
}
}
if (common > 0) {
List<string> rp = new List<string>();
for (int n = 0; n < (cwd.Length - common); n++) {
rp.Add("..");
}
for (int n = common; n < fp.Length; n++) {
rp.Add(fp[n]);
}
return String.Join("/", rp.ToArray());
} else {
return String.Join("/", fp);
}
}
public static string MakeRelativePath(string fromPath, string toPath, string sep = "/")
{
var fromParts = fromPath.Split(new[] { '/', '\\'},
StringSplitOptions.RemoveEmptyEntries);
var toParts = toPath.Split(new[] { '/', '\\'},
StringSplitOptions.RemoveEmptyEntries);
var matchedParts = fromParts
.Zip(toParts, (x, y) => string.Compare(x, y, true) == 0)
.TakeWhile(x => x).Count();
return string.Join("", Enumerable.Range(0, fromParts.Length - matchedParts)
.Select(x => ".." + sep)) +
string.Join(sep, toParts.Skip(matchedParts));
}
public static string RelativePathTo(this System.IO.DirectoryInfo @this, string to)
{
var rgFrom = @this.FullName.Split(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
var rgTo = to.Split(new[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
var cSame = rgFrom.TakeWhile((p, i) => i < rgTo.Length && string.Equals(p, rgTo[i])).Count();
return Path.Combine(
Enumerable.Range(0, rgFrom.Length - cSame)
.Select(_ => "..")
.Concat(rgTo.Skip(cSame))
.ToArray()
);
}
private String GetRelativePath(Int32 level, String directory, out String errorMessage) {
if (level < 0 || level > 5) {
errorMessage = "Find some more smart input data";
return String.Empty;
}
// ==========================
while (level != 0) {
directory = Path.GetDirectoryName(directory);
level -= 1;
}
// ==========================
errorMessage = String.Empty;
return directory;
}
[Test]
public void RelativeDirectoryPathTest() {
var relativePath =
GetRelativePath(3, AppDomain.CurrentDomain.BaseDirectory, out var errorMessage);
Console.WriteLine(relativePath);
if (String.IsNullOrEmpty(errorMessage) == false) {
Console.WriteLine(errorMessage);
Assert.Fail("Can not find relative path");
}
}
var relativeTo = @"C:\Program Files\Dummy Folder\MyProgram";
var path = @"C:\Program Files\Dummy Folder\MyProgram\Data\datafile1.dat";
string relativePath = System.IO.Path.GetRelativePath(relativeTo, path);
System.Console.WriteLine(relativePath);
// output --> Data\datafile1.dat
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//Adapted from https://github.com/dotnet/corefx/blob/master/src/Common/src/CoreLib/System/IO/Path.cs#L697
// by Anton Krouglov
using System.Runtime.CompilerServices;
using System.Diagnostics;
using System.Text;
using Xunit;
namespace System.IO {
// Provides methods for processing file system strings in a cross-platform manner.
// Most of the methods don't do a complete parsing (such as examining a UNC hostname),
// but they will handle most string operations.
public static class PathNetCore {
/// <summary>
/// Create a relative path from one path to another. Paths will be resolved before calculating the difference.
/// Default path comparison for the active platform will be used (OrdinalIgnoreCase for Windows or Mac, Ordinal for Unix).
/// </summary>
/// <param name="relativeTo">The source path the output should be relative to. This path is always considered to be a directory.</param>
/// <param name="path">The destination path.</param>
/// <returns>The relative path or <paramref name="path"/> if the paths don't share the same root.</returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="relativeTo"/> or <paramref name="path"/> is <c>null</c> or an empty string.</exception>
public static string GetRelativePath(string relativeTo, string path) {
return GetRelativePath(relativeTo, path, StringComparison);
}
private static string GetRelativePath(string relativeTo, string path, StringComparison comparisonType) {
if (string.IsNullOrEmpty(relativeTo)) throw new ArgumentNullException(nameof(relativeTo));
if (string.IsNullOrEmpty(path)) throw new ArgumentNullException(nameof(path));
Debug.Assert(comparisonType == StringComparison.Ordinal ||
comparisonType == StringComparison.OrdinalIgnoreCase);
relativeTo = Path.GetFullPath(relativeTo);
path = Path.GetFullPath(path);
// Need to check if the roots are different- if they are we need to return the "to" path.
if (!PathInternalNetCore.AreRootsEqual(relativeTo, path, comparisonType))
return path;
int commonLength = PathInternalNetCore.GetCommonPathLength(relativeTo, path,
ignoreCase: comparisonType == StringComparison.OrdinalIgnoreCase);
// If there is nothing in common they can't share the same root, return the "to" path as is.
if (commonLength == 0)
return path;
// Trailing separators aren't significant for comparison
int relativeToLength = relativeTo.Length;
if (PathInternalNetCore.EndsInDirectorySeparator(relativeTo))
relativeToLength--;
bool pathEndsInSeparator = PathInternalNetCore.EndsInDirectorySeparator(path);
int pathLength = path.Length;
if (pathEndsInSeparator)
pathLength--;
// If we have effectively the same path, return "."
if (relativeToLength == pathLength && commonLength >= relativeToLength) return ".";
// We have the same root, we need to calculate the difference now using the
// common Length and Segment count past the length.
//
// Some examples:
//
// C:\Foo C:\Bar L3, S1 -> ..\Bar
// C:\Foo C:\Foo\Bar L6, S0 -> Bar
// C:\Foo\Bar C:\Bar\Bar L3, S2 -> ..\..\Bar\Bar
// C:\Foo\Foo C:\Foo\Bar L7, S1 -> ..\Bar
StringBuilder
sb = new StringBuilder(); //StringBuilderCache.Acquire(Math.Max(relativeTo.Length, path.Length));
// Add parent segments for segments past the common on the "from" path
if (commonLength < relativeToLength) {
sb.Append("..");
for (int i = commonLength + 1; i < relativeToLength; i++) {
if (PathInternalNetCore.IsDirectorySeparator(relativeTo[i])) {
sb.Append(DirectorySeparatorChar);
sb.Append("..");
}
}
}
else if (PathInternalNetCore.IsDirectorySeparator(path[commonLength])) {
// No parent segments and we need to eat the initial separator
// (C:\Foo C:\Foo\Bar case)
commonLength++;
}
// Now add the rest of the "to" path, adding back the trailing separator
int differenceLength = pathLength - commonLength;
if (pathEndsInSeparator)
differenceLength++;
if (differenceLength > 0) {
if (sb.Length > 0) {
sb.Append(DirectorySeparatorChar);
}
sb.Append(path, commonLength, differenceLength);
}
return sb.ToString(); //StringBuilderCache.GetStringAndRelease(sb);
}
// Public static readonly variant of the separators. The Path implementation itself is using
// internal const variant of the separators for better performance.
public static readonly char DirectorySeparatorChar = PathInternalNetCore.DirectorySeparatorChar;
public static readonly char AltDirectorySeparatorChar = PathInternalNetCore.AltDirectorySeparatorChar;
public static readonly char VolumeSeparatorChar = PathInternalNetCore.VolumeSeparatorChar;
public static readonly char PathSeparator = PathInternalNetCore.PathSeparator;
/// <summary>Returns a comparison that can be used to compare file and directory names for equality.</summary>
internal static StringComparison StringComparison => StringComparison.OrdinalIgnoreCase;
}
/// <summary>Contains internal path helpers that are shared between many projects.</summary>
internal static class PathInternalNetCore {
internal const char DirectorySeparatorChar = '\\';
internal const char AltDirectorySeparatorChar = '/';
internal const char VolumeSeparatorChar = ':';
internal const char PathSeparator = ';';
internal const string ExtendedDevicePathPrefix = @"\\?\";
internal const string UncPathPrefix = @"\\";
internal const string UncDevicePrefixToInsert = @"?\UNC\";
internal const string UncExtendedPathPrefix = @"\\?\UNC\";
internal const string DevicePathPrefix = @"\\.\";
//internal const int MaxShortPath = 260;
// \\?\, \\.\, \??\
internal const int DevicePrefixLength = 4;
/// <summary>
/// Returns true if the two paths have the same root
/// </summary>
internal static bool AreRootsEqual(string first, string second, StringComparison comparisonType) {
int firstRootLength = GetRootLength(first);
int secondRootLength = GetRootLength(second);
return firstRootLength == secondRootLength
&& string.Compare(
strA: first,
indexA: 0,
strB: second,
indexB: 0,
length: firstRootLength,
comparisonType: comparisonType) == 0;
}
/// <summary>
/// Gets the length of the root of the path (drive, share, etc.).
/// </summary>
internal static int GetRootLength(string path) {
int i = 0;
int volumeSeparatorLength = 2; // Length to the colon "C:"
int uncRootLength = 2; // Length to the start of the server name "\\"
bool extendedSyntax = path.StartsWith(ExtendedDevicePathPrefix);
bool extendedUncSyntax = path.StartsWith(UncExtendedPathPrefix);
if (extendedSyntax) {
// Shift the position we look for the root from to account for the extended prefix
if (extendedUncSyntax) {
// "\\" -> "\\?\UNC\"
uncRootLength = UncExtendedPathPrefix.Length;
}
else {
// "C:" -> "\\?\C:"
volumeSeparatorLength += ExtendedDevicePathPrefix.Length;
}
}
if ((!extendedSyntax || extendedUncSyntax) && path.Length > 0 && IsDirectorySeparator(path[0])) {
// UNC or simple rooted path (e.g. "\foo", NOT "\\?\C:\foo")
i = 1; // Drive rooted (\foo) is one character
if (extendedUncSyntax || (path.Length > 1 && IsDirectorySeparator(path[1]))) {
// UNC (\\?\UNC\ or \\), scan past the next two directory separators at most
// (e.g. to \\?\UNC\Server\Share or \\Server\Share\)
i = uncRootLength;
int n = 2; // Maximum separators to skip
while (i < path.Length && (!IsDirectorySeparator(path[i]) || --n > 0)) i++;
}
}
else if (path.Length >= volumeSeparatorLength &&
path[volumeSeparatorLength - 1] == PathNetCore.VolumeSeparatorChar) {
// Path is at least longer than where we expect a colon, and has a colon (\\?\A:, A:)
// If the colon is followed by a directory separator, move past it
i = volumeSeparatorLength;
if (path.Length >= volumeSeparatorLength + 1 && IsDirectorySeparator(path[volumeSeparatorLength])) i++;
}
return i;
}
/// <summary>
/// True if the given character is a directory separator.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal static bool IsDirectorySeparator(char c) {
return c == PathNetCore.DirectorySeparatorChar || c == PathNetCore.AltDirectorySeparatorChar;
}
/// <summary>
/// Get the common path length from the start of the string.
/// </summary>
internal static int GetCommonPathLength(string first, string second, bool ignoreCase) {
int commonChars = EqualStartingCharacterCount(first, second, ignoreCase: ignoreCase);
// If nothing matches
if (commonChars == 0)
return commonChars;
// Or we're a full string and equal length or match to a separator
if (commonChars == first.Length
&& (commonChars == second.Length || IsDirectorySeparator(second[commonChars])))
return commonChars;
if (commonChars == second.Length && IsDirectorySeparator(first[commonChars]))
return commonChars;
// It's possible we matched somewhere in the middle of a segment e.g. C:\Foodie and C:\Foobar.
while (commonChars > 0 && !IsDirectorySeparator(first[commonChars - 1]))
commonChars--;
return commonChars;
}
/// <summary>
/// Gets the count of common characters from the left optionally ignoring case
/// </summary>
internal static unsafe int EqualStartingCharacterCount(string first, string second, bool ignoreCase) {
if (string.IsNullOrEmpty(first) || string.IsNullOrEmpty(second)) return 0;
int commonChars = 0;
fixed (char* f = first)
fixed (char* s = second) {
char* l = f;
char* r = s;
char* leftEnd = l + first.Length;
char* rightEnd = r + second.Length;
while (l != leftEnd && r != rightEnd
&& (*l == *r || (ignoreCase &&
char.ToUpperInvariant((*l)) == char.ToUpperInvariant((*r))))) {
commonChars++;
l++;
r++;
}
}
return commonChars;
}
/// <summary>
/// Returns true if the path ends in a directory separator.
/// </summary>
internal static bool EndsInDirectorySeparator(string path)
=> path.Length > 0 && IsDirectorySeparator(path[path.Length - 1]);
}
/// <summary> Tests for PathNetCore.GetRelativePath </summary>
public static class GetRelativePathTests {
[Theory]
[InlineData(@"C:\", @"C:\", @".")]
[InlineData(@"C:\a", @"C:\a\", @".")]
[InlineData(@"C:\A", @"C:\a\", @".")]
[InlineData(@"C:\a\", @"C:\a", @".")]
[InlineData(@"C:\", @"C:\b", @"b")]
[InlineData(@"C:\a", @"C:\b", @"..\b")]
[InlineData(@"C:\a", @"C:\b\", @"..\b\")]
[InlineData(@"C:\a\b", @"C:\a", @"..")]
[InlineData(@"C:\a\b", @"C:\a\", @"..")]
[InlineData(@"C:\a\b\", @"C:\a", @"..")]
[InlineData(@"C:\a\b\", @"C:\a\", @"..")]
[InlineData(@"C:\a\b\c", @"C:\a\b", @"..")]
[InlineData(@"C:\a\b\c", @"C:\a\b\", @"..")]
[InlineData(@"C:\a\b\c", @"C:\a", @"..\..")]
[InlineData(@"C:\a\b\c", @"C:\a\", @"..\..")]
[InlineData(@"C:\a\b\c\", @"C:\a\b", @"..")]
[InlineData(@"C:\a\b\c\", @"C:\a\b\", @"..")]
[InlineData(@"C:\a\b\c\", @"C:\a", @"..\..")]
[InlineData(@"C:\a\b\c\", @"C:\a\", @"..\..")]
[InlineData(@"C:\a\", @"C:\b", @"..\b")]
[InlineData(@"C:\a", @"C:\a\b", @"b")]
[InlineData(@"C:\a", @"C:\A\b", @"b")]
[InlineData(@"C:\a", @"C:\b\c", @"..\b\c")]
[InlineData(@"C:\a\", @"C:\a\b", @"b")]
[InlineData(@"C:\", @"D:\", @"D:\")]
[InlineData(@"C:\", @"D:\b", @"D:\b")]
[InlineData(@"C:\", @"D:\b\", @"D:\b\")]
[InlineData(@"C:\a", @"D:\b", @"D:\b")]
[InlineData(@"C:\a\", @"D:\b", @"D:\b")]
[InlineData(@"C:\ab", @"C:\a", @"..\a")]
[InlineData(@"C:\a", @"C:\ab", @"..\ab")]
[InlineData(@"C:\", @"\\LOCALHOST\Share\b", @"\\LOCALHOST\Share\b")]
[InlineData(@"\\LOCALHOST\Share\a", @"\\LOCALHOST\Share\b", @"..\b")]
//[PlatformSpecific(TestPlatforms.Windows)] // Tests Windows-specific paths
public static void GetRelativePath_Windows(string relativeTo, string path, string expected) {
string result = PathNetCore.GetRelativePath(relativeTo, path);
Assert.Equal(expected, result);
// Check that we get the equivalent path when the result is combined with the sources
Assert.Equal(
Path.GetFullPath(path).TrimEnd(Path.DirectorySeparatorChar),
Path.GetFullPath(Path.Combine(Path.GetFullPath(relativeTo), result))
.TrimEnd(Path.DirectorySeparatorChar),
ignoreCase: true,
ignoreLineEndingDifferences: false,
ignoreWhiteSpaceDifferences: false);
}
}
}
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
public class RenderingService : IRenderingService
{
private readonly IHostingEnvironment _hostingEnvironment;
public RenderingService(IHostingEnvironment hostingEnvironment)
{
_hostingEnvironment = hostingEnvironment;
}
public string RelativeAssemblyDirectory()
{
var contentRootPath = _hostingEnvironment.ContentRootPath;
string executingAssemblyDirectoryAbsolutePath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
string executingAssemblyDirectoryRelativePath = System.IO.Path.GetRelativePath(contentRootPath, executingAssemblyDirectoryAbsolutePath);
return executingAssemblyDirectoryRelativePath;
}
}