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Diffstat (limited to 'src/mscorlib/src/System/IO/PathInternal.cs')
| -rw-r--r-- | src/mscorlib/src/System/IO/PathInternal.cs | 806 |
1 files changed, 0 insertions, 806 deletions
diff --git a/src/mscorlib/src/System/IO/PathInternal.cs b/src/mscorlib/src/System/IO/PathInternal.cs deleted file mode 100644 index 3970e2264a..0000000000 --- a/src/mscorlib/src/System/IO/PathInternal.cs +++ /dev/null @@ -1,806 +0,0 @@ -// Copyright (c) Microsoft. All rights reserved. -// Licensed under the MIT license. See LICENSE file in the project root for full license information. - -using Microsoft.Win32; -using System; -using System.Diagnostics.Contracts; -using System.Runtime.CompilerServices; -using System.Runtime.InteropServices; -using System.Security; -using System.Text; - -namespace System.IO -{ - /// <summary>Contains internal path helpers that are shared between many projects.</summary> - internal static class PathInternal - { - internal const string ExtendedPathPrefix = @"\\?\"; - internal const string UncPathPrefix = @"\\"; - internal const string UncExtendedPrefixToInsert = @"?\UNC\"; - internal const string UncExtendedPathPrefix = @"\\?\UNC\"; - internal const string DevicePathPrefix = @"\\.\"; - // \\?\, \\.\, \??\ - internal const int DevicePrefixLength = 4; - // \\ - internal const int UncPrefixLength = 2; - // \\?\UNC\, \\.\UNC\ - internal const int UncExtendedPrefixLength = 8; -#if !PLATFORM_UNIX - internal const int MaxShortPath = 260; - internal const int MaxShortDirectoryPath = 248; -#else - internal const int MaxShortPath = 1024; - internal const int MaxShortDirectoryPath = MaxShortPath; -#endif - - // Windows is limited in long paths by the max size of its internal representation of a unicode string. - // UNICODE_STRING has a max length of USHORT in _bytes_ without a trailing null. - // https://msdn.microsoft.com/en-us/library/windows/hardware/ff564879.aspx - internal const int MaxLongPath = short.MaxValue; - internal static readonly int MaxComponentLength = 255; - -#if !PLATFORM_UNIX - internal static readonly char[] InvalidPathChars = - { - '\"', '<', '>', '|', '\0', - (char)1, (char)2, (char)3, (char)4, (char)5, (char)6, (char)7, (char)8, (char)9, (char)10, - (char)11, (char)12, (char)13, (char)14, (char)15, (char)16, (char)17, (char)18, (char)19, (char)20, - (char)21, (char)22, (char)23, (char)24, (char)25, (char)26, (char)27, (char)28, (char)29, (char)30, - (char)31 - }; -#else - internal static readonly char[] InvalidPathChars = { '\0' }; -#endif - - - /// <summary> - /// Validates volume separator only occurs as C: or \\?\C:. This logic is meant to filter out Alternate Data Streams. - /// </summary> - /// <returns>True if the path has an invalid volume separator.</returns> - internal static bool HasInvalidVolumeSeparator(string path) - { - // Toss out paths with colons that aren't a valid drive specifier. - // Cannot start with a colon and can only be of the form "C:" or "\\?\C:". - // (Note that we used to explicitly check "http:" and "file:"- these are caught by this check now.) - - // We don't care about skipping starting space for extended paths. Assume no knowledge of extended paths if we're forcing old path behavior. - bool isExtended = -#if FEATURE_PATHCOMPAT - !AppContextSwitches.UseLegacyPathHandling && -#endif - IsExtended(path); - int startIndex = isExtended ? ExtendedPathPrefix.Length : PathStartSkip(path); - - // If we start with a colon - if ((path.Length > startIndex && path[startIndex] == Path.VolumeSeparatorChar) - // Or have an invalid drive letter and colon - || (path.Length >= startIndex + 2 && path[startIndex + 1] == Path.VolumeSeparatorChar && !IsValidDriveChar(path[startIndex])) - // Or have any colons beyond the drive colon - || (path.Length > startIndex + 2 && path.IndexOf(Path.VolumeSeparatorChar, startIndex + 2) != -1)) - { - return true; - } - - return false; - } - - /// <summary> - /// Returns true if the given StringBuilder starts with the given value. - /// </summary> - /// <param name="value">The string to compare against the start of the StringBuilder.</param> - internal static bool StartsWithOrdinal(StringBuilder builder, string value, bool ignoreCase = false) - { - if (value == null || builder.Length < value.Length) - return false; - - if (ignoreCase) - { - for (int i = 0; i < value.Length; i++) - if (char.ToUpperInvariant(builder[i]) != char.ToUpperInvariant(value[i])) return false; - } - else - { - for (int i = 0; i < value.Length; i++) - if (builder[i] != value[i]) return false; - } - - return true; - } - - /// <summary> - /// Returns true if the given character is a valid drive letter - /// </summary> - internal static bool IsValidDriveChar(char value) - { - return ((value >= 'A' && value <= 'Z') || (value >= 'a' && value <= 'z')); - } - - /// <summary> - /// Returns true if the path is too long - /// </summary> - internal static bool IsPathTooLong(string fullPath) - { - // We'll never know precisely what will fail as paths get changed internally in Windows and - // may grow beyond / shrink below exceed MaxLongPath. -#if FEATURE_PATHCOMPAT - if (AppContextSwitches.BlockLongPaths) - { - // We allow paths of any length if extended (and not in compat mode) - if (AppContextSwitches.UseLegacyPathHandling || !IsExtended(fullPath)) - return fullPath.Length >= MaxShortPath; - } -#endif - - return fullPath.Length >= MaxLongPath; - } - - /// <summary> - /// Return true if any path segments are too long - /// </summary> - internal static bool AreSegmentsTooLong(string fullPath) - { - int length = fullPath.Length; - int lastSeparator = 0; - - for (int i = 0; i < length; i++) - { - if (IsDirectorySeparator(fullPath[i])) - { - if (i - lastSeparator > MaxComponentLength) - return true; - lastSeparator = i; - } - } - - if (length - 1 - lastSeparator > MaxComponentLength) - return true; - - return false; - } - - /// <summary> - /// Returns true if the directory is too long - /// </summary> - internal static bool IsDirectoryTooLong(string fullPath) - { -#if FEATURE_PATHCOMPAT - if (AppContextSwitches.BlockLongPaths) - { - // We allow paths of any length if extended (and not in compat mode) - if (AppContextSwitches.UseLegacyPathHandling || !IsExtended(fullPath)) - return (fullPath.Length >= MaxShortDirectoryPath); - } -#endif - - return IsPathTooLong(fullPath); - } - - /// <summary> - /// Adds the extended path prefix (\\?\) if not relative or already a device path. - /// </summary> - internal static string EnsureExtendedPrefix(string path) - { - // Putting the extended prefix on the path changes the processing of the path. It won't get normalized, which - // means adding to relative paths will prevent them from getting the appropriate current directory inserted. - - // If it already has some variant of a device path (\??\, \\?\, \\.\, //./, etc.) we don't need to change it - // as it is either correct or we will be changing the behavior. When/if Windows supports long paths implicitly - // in the future we wouldn't want normalization to come back and break existing code. - - // In any case, all internal usages should be hitting normalize path (Path.GetFullPath) before they hit this - // shimming method. (Or making a change that doesn't impact normalization, such as adding a filename to a - // normalized base path.) - if (IsPartiallyQualified(path) || IsDevice(path)) - return path; - - // Given \\server\share in longpath becomes \\?\UNC\server\share - if (path.StartsWith(UncPathPrefix, StringComparison.OrdinalIgnoreCase)) - return path.Insert(2, UncExtendedPrefixToInsert); - - return ExtendedPathPrefix + path; - } - - /// <summary> - /// Removes the extended path prefix (\\?\) if present. - /// </summary> - internal static string RemoveExtendedPrefix(string path) - { - if (!IsExtended(path)) - return path; - - // Given \\?\UNC\server\share we return \\server\share - if (IsExtendedUnc(path)) - return path.Remove(2, 6); - - return path.Substring(DevicePrefixLength); - } - - /// <summary> - /// Removes the extended path prefix (\\?\) if present. - /// </summary> - internal static StringBuilder RemoveExtendedPrefix(StringBuilder path) - { - if (!IsExtended(path)) - return path; - - // Given \\?\UNC\server\share we return \\server\share - if (IsExtendedUnc(path)) - return path.Remove(2, 6); - - return path.Remove(0, DevicePrefixLength); - } - - /// <summary> - /// Returns true if the path uses any of the DOS device path syntaxes. ("\\.\", "\\?\", or "\??\") - /// </summary> - internal static bool IsDevice(string path) - { - // If the path begins with any two separators it will be recognized and normalized and prepped with - // "\??\" for internal usage correctly. "\??\" is recognized and handled, "/??/" is not. - return IsExtended(path) - || - ( - path.Length >= DevicePrefixLength - && IsDirectorySeparator(path[0]) - && IsDirectorySeparator(path[1]) - && (path[2] == '.' || path[2] == '?') - && IsDirectorySeparator(path[3]) - ); - } - - /// <summary> - /// Returns true if the path uses any of the DOS device path syntaxes. ("\\.\", "\\?\", or "\??\") - /// </summary> - internal static bool IsDevice(StringBuffer path) - { - // If the path begins with any two separators it will be recognized and normalized and prepped with - // "\??\" for internal usage correctly. "\??\" is recognized and handled, "/??/" is not. - return IsExtended(path) - || - ( - path.Length >= DevicePrefixLength - && IsDirectorySeparator(path[0]) - && IsDirectorySeparator(path[1]) - && (path[2] == '.' || path[2] == '?') - && IsDirectorySeparator(path[3]) - ); - } - - /// <summary> - /// Returns true if the path uses the canonical form of extended syntax ("\\?\" or "\??\"). If the - /// path matches exactly (cannot use alternate directory separators) Windows will skip normalization - /// and path length checks. - /// </summary> - internal static bool IsExtended(string path) - { - // While paths like "//?/C:/" will work, they're treated the same as "\\.\" paths. - // Skipping of normalization will *only* occur if back slashes ('\') are used. - return path.Length >= DevicePrefixLength - && path[0] == '\\' - && (path[1] == '\\' || path[1] == '?') - && path[2] == '?' - && path[3] == '\\'; - } - - /// <summary> - /// Returns true if the path uses the canonical form of extended syntax ("\\?\" or "\??\"). If the - /// path matches exactly (cannot use alternate directory separators) Windows will skip normalization - /// and path length checks. - /// </summary> - internal static bool IsExtended(StringBuilder path) - { - // While paths like "//?/C:/" will work, they're treated the same as "\\.\" paths. - // Skipping of normalization will *only* occur if back slashes ('\') are used. - return path.Length >= DevicePrefixLength - && path[0] == '\\' - && (path[1] == '\\' || path[1] == '?') - && path[2] == '?' - && path[3] == '\\'; - } - - /// <summary> - /// Returns true if the path uses the canonical form of extended syntax ("\\?\" or "\??\"). If the - /// path matches exactly (cannot use alternate directory separators) Windows will skip normalization - /// and path length checks. - /// </summary> - internal static bool IsExtended(StringBuffer path) - { - // While paths like "//?/C:/" will work, they're treated the same as "\\.\" paths. - // Skipping of normalization will *only* occur if back slashes ('\') are used. - return path.Length >= DevicePrefixLength - && path[0] == '\\' - && (path[1] == '\\' || path[1] == '?') - && path[2] == '?' - && path[3] == '\\'; - } - - /// <summary> - /// Returns true if the path uses the extended UNC syntax (\\?\UNC\ or \??\UNC\) - /// </summary> - internal static bool IsExtendedUnc(string path) - { - return path.Length >= UncExtendedPathPrefix.Length - && IsExtended(path) - && char.ToUpper(path[4]) == 'U' - && char.ToUpper(path[5]) == 'N' - && char.ToUpper(path[6]) == 'C' - && path[7] == '\\'; - } - - /// <summary> - /// Returns true if the path uses the extended UNC syntax (\\?\UNC\ or \??\UNC\) - /// </summary> - internal static bool IsExtendedUnc(StringBuilder path) - { - return path.Length >= UncExtendedPathPrefix.Length - && IsExtended(path) - && char.ToUpper(path[4]) == 'U' - && char.ToUpper(path[5]) == 'N' - && char.ToUpper(path[6]) == 'C' - && path[7] == '\\'; - } - - /// <summary> - /// Returns a value indicating if the given path contains invalid characters (", <, >, | - /// NUL, or any ASCII char whose integer representation is in the range of 1 through 31). - /// Does not check for wild card characters ? and *. - /// - /// Will not check if the path is a device path and not in Legacy mode as many of these - /// characters are valid for devices (pipes for example). - /// </summary> - internal static bool HasIllegalCharacters(string path, bool checkAdditional = false) - { - if ( -#if FEATURE_PATHCOMPAT - !AppContextSwitches.UseLegacyPathHandling && -#endif - IsDevice(path)) - { - return false; - } - - return AnyPathHasIllegalCharacters(path, checkAdditional: checkAdditional); - } - - /// <summary> - /// Version of HasIllegalCharacters that checks no AppContextSwitches. Only use if you know you need to skip switches and don't care - /// about proper device path handling. - /// </summary> - internal static bool AnyPathHasIllegalCharacters(string path, bool checkAdditional = false) - { - return path.IndexOfAny(InvalidPathChars) >= 0 -#if !PLATFORM_UNIX - || (checkAdditional && AnyPathHasWildCardCharacters(path)) -#endif - ; - } - - /// <summary> - /// Check for ? and *. - /// </summary> - internal static bool HasWildCardCharacters(string path) - { - // Question mark is part of some device paths - int startIndex = -#if FEATURE_PATHCOMPAT - AppContextSwitches.UseLegacyPathHandling ? 0 : -#endif - IsDevice(path) ? ExtendedPathPrefix.Length : 0; - return AnyPathHasWildCardCharacters(path, startIndex: startIndex); - } - - /// <summary> - /// Version of HasWildCardCharacters that checks no AppContextSwitches. Only use if you know you need to skip switches and don't care - /// about proper device path handling. - /// </summary> - internal static bool AnyPathHasWildCardCharacters(string path, int startIndex = 0) - { - char currentChar; - for (int i = startIndex; i < path.Length; i++) - { - currentChar = path[i]; - if (currentChar == '*' || currentChar == '?') return true; - } - return false; - } - - /// <summary> - /// Gets the length of the root of the path (drive, share, etc.). - /// </summary> - [System.Security.SecuritySafeCritical] - internal unsafe static int GetRootLength(string path) - { - fixed (char* value = path) - { - return (int)GetRootLength(value, (ulong)path.Length); - } - } - - /// <summary> - /// Gets the length of the root of the path (drive, share, etc.). - /// </summary> - [System.Security.SecuritySafeCritical] - internal unsafe static uint GetRootLength(StringBuffer path) - { - if (path.Length == 0) return 0; - return GetRootLength(path.CharPointer, path.Length); - } - - [System.Security.SecurityCritical] - private unsafe static uint GetRootLength(char* path, ulong pathLength) - { - uint i = 0; - -#if PLATFORM_UNIX - if (pathLength >= 1 && (IsDirectorySeparator(path[0]))) - i = 1; -#else - uint volumeSeparatorLength = 2; // Length to the colon "C:" - uint uncRootLength = 2; // Length to the start of the server name "\\" - - bool extendedSyntax = StartsWithOrdinal(path, pathLength, ExtendedPathPrefix); - bool extendedUncSyntax = StartsWithOrdinal(path, pathLength, UncExtendedPathPrefix); - if (extendedSyntax) - { - // Shift the position we look for the root from to account for the extended prefix - if (extendedUncSyntax) - { - // "\\" -> "\\?\UNC\" - uncRootLength = (uint)UncExtendedPathPrefix.Length; - } - else - { - // "C:" -> "\\?\C:" - volumeSeparatorLength += (uint)ExtendedPathPrefix.Length; - } - } - - if ((!extendedSyntax || extendedUncSyntax) && pathLength > 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 || (pathLength > 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 < pathLength && (!IsDirectorySeparator(path[i]) || --n > 0)) i++; - } - } - else if (pathLength >= volumeSeparatorLength && path[volumeSeparatorLength - 1] == Path.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 (pathLength >= volumeSeparatorLength + 1 && IsDirectorySeparator(path[volumeSeparatorLength])) i++; - } -#endif // !PLATFORM_UNIX - return i; - } - - [System.Security.SecurityCritical] - private unsafe static bool StartsWithOrdinal(char* source, ulong sourceLength, string value) - { - if (sourceLength < (ulong)value.Length) return false; - for (int i = 0; i < value.Length; i++) - { - if (value[i] != source[i]) return false; - } - return true; - } - - /// <summary> - /// Returns true if the path specified is relative to the current drive or working directory. - /// Returns false if the path is fixed to a specific drive or UNC path. This method does no - /// validation of the path (URIs will be returned as relative as a result). - /// </summary> - /// <remarks> - /// Handles paths that use the alternate directory separator. It is a frequent mistake to - /// assume that rooted paths (Path.IsPathRooted) are not relative. This isn't the case. - /// "C:a" is drive relative- meaning that it will be resolved against the current directory - /// for C: (rooted, but relative). "C:\a" is rooted and not relative (the current directory - /// will not be used to modify the path). - /// </remarks> - internal static bool IsPartiallyQualified(string path) - { -#if PLATFORM_UNIX - return !(path.Length >= 1 && path[0] == Path.DirectorySeparatorChar); -#else - if (path.Length < 2) - { - // It isn't fixed, it must be relative. There is no way to specify a fixed - // path with one character (or less). - return true; - } - - if (IsDirectorySeparator(path[0])) - { - // There is no valid way to specify a relative path with two initial slashes or - // \? as ? isn't valid for drive relative paths and \??\ is equivalent to \\?\ - return !(path[1] == '?' || IsDirectorySeparator(path[1])); - } - - // The only way to specify a fixed path that doesn't begin with two slashes - // is the drive, colon, slash format- i.e. C:\ - return !((path.Length >= 3) - && (path[1] == Path.VolumeSeparatorChar) - && IsDirectorySeparator(path[2]) - // To match old behavior we'll check the drive character for validity as the path is technically - // not qualified if you don't have a valid drive. "=:\" is the "=" file's default data stream. - && IsValidDriveChar(path[0])); -#endif // !PLATFORM_UNIX - } - - /// <summary> - /// Returns true if the path specified is relative to the current drive or working directory. - /// Returns false if the path is fixed to a specific drive or UNC path. This method does no - /// validation of the path (URIs will be returned as relative as a result). - /// </summary> - /// <remarks> - /// Handles paths that use the alternate directory separator. It is a frequent mistake to - /// assume that rooted paths (Path.IsPathRooted) are not relative. This isn't the case. - /// "C:a" is drive relative- meaning that it will be resolved against the current directory - /// for C: (rooted, but relative). "C:\a" is rooted and not relative (the current directory - /// will not be used to modify the path). - /// </remarks> - internal static bool IsPartiallyQualified(StringBuffer path) - { -#if PLATFORM_UNIX - return !(path.Length >= 1 && path[0] == Path.DirectorySeparatorChar); -#else - if (path.Length < 2) - { - // It isn't fixed, it must be relative. There is no way to specify a fixed - // path with one character (or less). - return true; - } - - if (IsDirectorySeparator(path[0])) - { - // There is no valid way to specify a relative path with two initial slashes or - // \? as ? isn't valid for drive relative paths and \??\ is equivalent to \\?\ - return !(path[1] == '?' || IsDirectorySeparator(path[1])); - } - - // The only way to specify a fixed path that doesn't begin with two slashes - // is the drive, colon, slash format- i.e. C:\ - return !((path.Length >= 3) - && (path[1] == Path.VolumeSeparatorChar) - && IsDirectorySeparator(path[2]) - // To match old behavior we'll check the drive character for validity as the path is technically - // not qualified if you don't have a valid drive. "=:\" is the "=" file's default data stream. - && IsValidDriveChar(path[0])); -#endif // !PLATFORM_UNIX - } - - /// <summary> - /// On Windows, returns the characters to skip at the start of the path if it starts with space(s) and a drive or directory separator. - /// (examples are " C:", " \") - /// This is a legacy behavior of Path.GetFullPath(). - /// </summary> - /// <remarks> - /// Note that this conflicts with IsPathRooted() which doesn't (and never did) such a skip. - /// </remarks> - internal static int PathStartSkip(string path) - { -#if !PLATFORM_UNIX - int startIndex = 0; - while (startIndex < path.Length && path[startIndex] == ' ') startIndex++; - - if (startIndex > 0 && (startIndex < path.Length && IsDirectorySeparator(path[startIndex])) - || (startIndex + 1 < path.Length && path[startIndex + 1] == Path.VolumeSeparatorChar && IsValidDriveChar(path[startIndex]))) - { - // Go ahead and skip spaces as we're either " C:" or " \" - return startIndex; - } -#endif - - return 0; - } - - /// <summary> - /// True if the given character is a directory separator. - /// </summary> - [MethodImpl(MethodImplOptions.AggressiveInlining)] - internal static bool IsDirectorySeparator(char c) - { - return c == Path.DirectorySeparatorChar -#if !PLATFORM_UNIX - || c == Path.AltDirectorySeparatorChar -#endif - ; - } - - /// <summary> - /// Normalize separators in the given path. Converts forward slashes into back slashes and compresses slash runs, keeping initial 2 if present. - /// Also trims initial whitespace in front of "rooted" paths (see PathStartSkip). - /// - /// This effectively replicates the behavior of the legacy NormalizePath when it was called with fullCheck=false and expandShortpaths=false. - /// The current NormalizePath gets directory separator normalization from Win32's GetFullPathName(), which will resolve relative paths and as - /// such can't be used here (and is overkill for our uses). - /// - /// Like the current NormalizePath this will not try and analyze periods/spaces within directory segments. - /// </summary> - /// <remarks> - /// The only callers that used to use Path.Normalize(fullCheck=false) were Path.GetDirectoryName() and Path.GetPathRoot(). Both usages do - /// not need trimming of trailing whitespace here. - /// - /// GetPathRoot() could technically skip normalizing separators after the second segment- consider as a future optimization. - /// - /// For legacy desktop behavior with ExpandShortPaths: - /// - It has no impact on GetPathRoot() so doesn't need consideration. - /// - It could impact GetDirectoryName(), but only if the path isn't relative (C:\ or \\Server\Share). - /// - /// In the case of GetDirectoryName() the ExpandShortPaths behavior was undocumented and provided inconsistent results if the path was - /// fixed/relative. For example: "C:\PROGRA~1\A.TXT" would return "C:\Program Files" while ".\PROGRA~1\A.TXT" would return ".\PROGRA~1". If you - /// ultimately call GetFullPath() this doesn't matter, but if you don't or have any intermediate string handling could easily be tripped up by - /// this undocumented behavior. - /// </remarks> - internal static string NormalizeDirectorySeparators(string path) - { - if (string.IsNullOrEmpty(path)) return path; - - char current; - int start = PathStartSkip(path); - - if (start == 0) - { - // Make a pass to see if we need to normalize so we can potentially skip allocating - bool normalized = true; - - for (int i = 0; i < path.Length; i++) - { - current = path[i]; - if (IsDirectorySeparator(current) - && (current != Path.DirectorySeparatorChar -#if !PLATFORM_UNIX - // Check for sequential separators past the first position (we need to keep initial two for UNC/extended) - || (i > 0 && i + 1 < path.Length && IsDirectorySeparator(path[i + 1])) -#endif - )) - { - normalized = false; - break; - } - } - - if (normalized) return path; - } - - StringBuilder builder = StringBuilderCache.Acquire(path.Length); - -#if !PLATFORM_UNIX - // On Windows we always keep the first separator, even if the next is a separator (we need to keep initial two for UNC/extended) - if (IsDirectorySeparator(path[start])) - { - start++; - builder.Append(Path.DirectorySeparatorChar); - } -#endif - - for (int i = start; i < path.Length; i++) - { - current = path[i]; - - // If we have a separator - if (IsDirectorySeparator(current)) - { - // If the next is a separator, skip adding this - if (i + 1 < path.Length && IsDirectorySeparator(path[i + 1])) - { - continue; - } - - // Ensure it is the primary separator - current = Path.DirectorySeparatorChar; - } - - builder.Append(current); - } - - return StringBuilderCache.GetStringAndRelease(builder); - } - -#if PLATFORM_UNIX - // We rely on Windows to remove relative segments on Windows. This would need to be updated to - // handle the proper rooting on Windows if we for some reason need it. - - /// <summary> - /// Try to remove relative segments from the given path (without combining with a root). - /// </summary> - /// <param name="skip">Skip the specified number of characters before evaluating.</param> - internal static string RemoveRelativeSegments(string path, int skip = 0) - { - bool flippedSeparator = false; - - // Remove "//", "/./", and "/../" from the path by copying each character to the output, - // except the ones we're removing, such that the builder contains the normalized path - // at the end. - var sb = StringBuilderCache.Acquire(path.Length); - if (skip > 0) - { - sb.Append(path, 0, skip); - } - - int componentCharCount = 0; - for (int i = skip; i < path.Length; i++) - { - char c = path[i]; - - if (PathInternal.IsDirectorySeparator(c) && i + 1 < path.Length) - { - componentCharCount = 0; - - // Skip this character if it's a directory separator and if the next character is, too, - // e.g. "parent//child" => "parent/child" - if (PathInternal.IsDirectorySeparator(path[i + 1])) - { - continue; - } - - // Skip this character and the next if it's referring to the current directory, - // e.g. "parent/./child" =? "parent/child" - if ((i + 2 == path.Length || PathInternal.IsDirectorySeparator(path[i + 2])) && - path[i + 1] == '.') - { - i++; - continue; - } - - // Skip this character and the next two if it's referring to the parent directory, - // e.g. "parent/child/../grandchild" => "parent/grandchild" - if (i + 2 < path.Length && - (i + 3 == path.Length || PathInternal.IsDirectorySeparator(path[i + 3])) && - path[i + 1] == '.' && path[i + 2] == '.') - { - // Unwind back to the last slash (and if there isn't one, clear out everything). - int s; - for (s = sb.Length - 1; s >= 0; s--) - { - if (PathInternal.IsDirectorySeparator(sb[s])) - { - sb.Length = s; - break; - } - } - if (s < 0) - { - sb.Length = 0; - } - - i += 2; - continue; - } - } - - if (++componentCharCount > PathInternal.MaxComponentLength) - { - throw new PathTooLongException(); - } - - // Normalize the directory separator if needed - if (c != Path.DirectorySeparatorChar && c == Path.AltDirectorySeparatorChar) - { - c = Path.DirectorySeparatorChar; - flippedSeparator = true; - } - - sb.Append(c); - } - - if (flippedSeparator || sb.Length != path.Length) - { - return StringBuilderCache.GetStringAndRelease(sb); - } - else - { - // We haven't changed the source path, return the original - StringBuilderCache.Release(sb); - return path; - } - } -#endif // PLATFORM_UNIX - } -}
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