internal static int PrependDevicePathChars(ref ValueStringBuilder content, bool isDosUnc, ref ValueStringBuilder buffer)
{
int length = content.Length;
length += isDosUnc
? PathInternal.UncExtendedPrefixLength - PathInternal.UncPrefixLength
: PathInternal.DevicePrefixLength;
buffer.EnsureCapacity(length + 1);
buffer.Length = 0;
if (isDosUnc)
{
// Is a \\Server\Share, put \\?\UNC\ in the front
buffer.Append(PathInternal.UncExtendedPathPrefix);
// Copy Server\Share\... over to the buffer
buffer.Append(content.AsSpan(PathInternal.UncPrefixLength));
// Return the prefix difference
return(PathInternal.UncExtendedPrefixLength - PathInternal.UncPrefixLength);
}
else
{
// Not an UNC, put the \\?\ prefix in front, then the original string
buffer.Append(PathInternal.ExtendedPathPrefix);
buffer.Append(content.AsSpan());
return(PathInternal.DevicePrefixLength);
}
}
public static void HtmlDecode(string?value, TextWriter output)
{
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
if (string.IsNullOrEmpty(value))
{
output.Write(value);
return;
}
ReadOnlySpan <char> valueSpan = value.AsSpan();
int index = IndexOfHtmlDecodingChars(valueSpan);
if (index == -1)
{
output.Write(value);
return;
}
// In the worst case the decoded string has the same length.
// For small inputs we use stack allocation.
ValueStringBuilder sb = value.Length <= 256 ?
new ValueStringBuilder(stackalloc char[256]) :
new ValueStringBuilder(value.Length);
sb.Append(valueSpan.Slice(0, index));
HtmlDecode(valueSpan.Slice(index), ref sb);
output.Write(sb.AsSpan());
sb.Dispose();
}
internal static string Normalize(string path)
{
Span <char> initialBuffer = stackalloc char[PathInternal.MaxShortPath];
var builder = new ValueStringBuilder(initialBuffer);
// Get the full path
GetFullPathName(path.AsSpan(), ref builder);
// If we have the exact same string we were passed in, don't allocate another string.
// TryExpandShortName does this input identity check.
string result = builder.AsSpan().IndexOf('~') >= 0
? TryExpandShortFileName(ref builder, originalPath: path)
: builder.AsSpan().Equals(path.AsSpan(), StringComparison.Ordinal) ? path : builder.ToString();
// Clear the buffer
builder.Dispose();
return(result);
}
internal static unsafe char[] UnescapeString(char *pStr, int start, int end, char[] dest, ref int destPosition,
char rsvd1, char rsvd2, char rsvd3, UnescapeMode unescapeMode, UriParser?syntax, bool isQuery)
{
ValueStringBuilder vsb = new ValueStringBuilder(dest.Length);
vsb.Append(dest.AsSpan(0, destPosition));
UnescapeString(pStr, start, end, ref vsb, rsvd1, rsvd2, rsvd3, unescapeMode,
syntax, isQuery);
if (vsb.Length > dest.Length)
{
dest = vsb.AsSpan().ToArray();
}
else
{
vsb.AsSpan(destPosition).TryCopyTo(dest.AsSpan(destPosition));
}
destPosition = vsb.Length;
vsb.Dispose();
return(dest);
}
// In case of link target being relative:
// Preserve the full path of the directory of the previous path
// so the final target is returned with a valid full path
static void GetLinkTargetFullPath(ref ValueStringBuilder sb, ReadOnlySpan <char> linkTarget)
{
if (PathInternal.IsPartiallyQualified(linkTarget))
{
sb.Length = Path.GetDirectoryNameOffset(sb.AsSpan());
sb.Append(PathInternal.DirectorySeparatorChar);
}
else
{
sb.Length = 0;
}
sb.Append(linkTarget);
}
internal static string Normalize(ref ValueStringBuilder path)
{
var builder = new ValueStringBuilder(stackalloc char[PathInternal.MaxShortPath]);
// Get the full path
GetFullPathName(path.AsSpan(terminate: true), ref builder);
string result = builder.AsSpan().IndexOf('~') >= 0
? TryExpandShortFileName(ref builder, originalPath: null)
: builder.ToString();
// Clear the buffer
builder.Dispose();
return(result);
}
public static string UnescapeDataString(string stringToUnescape)
{
if ((object)stringToUnescape == null)
{
throw new ArgumentNullException(nameof(stringToUnescape));
}
if (stringToUnescape.Length == 0)
{
return(string.Empty);
}
unsafe
{
fixed(char *pStr = stringToUnescape)
{
int position;
for (position = 0; position < stringToUnescape.Length; ++position)
{
if (pStr[position] == '%')
{
break;
}
}
if (position == stringToUnescape.Length)
{
return(stringToUnescape);
}
UnescapeMode unescapeMode = UnescapeMode.Unescape | UnescapeMode.UnescapeAll;
position = 0;
ValueStringBuilder vsb = new ValueStringBuilder(stringToUnescape.Length);
UriHelper.UnescapeString(stringToUnescape, 0, stringToUnescape.Length, ref vsb, ref position,
c_DummyChar, c_DummyChar, c_DummyChar, unescapeMode, null, false);
ReadOnlySpan <char> resultSpan = vsb.AsSpan(0, position);
string result = resultSpan.SequenceEqual(stringToUnescape) ? stringToUnescape : resultSpan.ToString();
vsb.Dispose();
return(result);
}
}
}
public void AsSpan_ReturnsCorrectValue_DoesntClearBuilder()
{
var sb = new StringBuilder();
var vsb = new ValueStringBuilder();
for (int i = 1; i <= 100; i++)
{
string s = i.ToString();
sb.Append(s);
vsb.Append(s);
}
var resultString = new string(vsb.AsSpan());
Assert.Equal(sb.ToString(), resultString);
Assert.NotEqual(0, sb.Length);
Assert.Equal(sb.Length, vsb.Length);
}
public static void HtmlEncode(string?value, TextWriter output)
{
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
if (string.IsNullOrEmpty(value))
{
output.Write(value);
return;
}
ReadOnlySpan <char> valueSpan = value.AsSpan();
// Don't create ValueStringBuilder if we don't have anything to encode
int index = IndexOfHtmlEncodingChars(valueSpan);
if (index == -1)
{
output.Write(value);
return;
}
// For small inputs we allocate on the stack. In most cases a buffer three
// times larger the original string should be sufficient as usually not all
// characters need to be encoded.
// For larger string we rent the input string's length plus a fixed
// conservative amount of chars from the ArrayPool.
Span <char> buffer = value.Length < 80 ?
stackalloc char[256] :
null;
ValueStringBuilder sb = buffer != null ?
new ValueStringBuilder(buffer) :
new ValueStringBuilder(value.Length + 200);
sb.Append(valueSpan.Slice(0, index));
HtmlEncode(valueSpan.Slice(index), ref sb);
output.Write(sb.AsSpan());
sb.Dispose();
}
internal static string TryExpandShortFileName(ref ValueStringBuilder outputBuilder, string?originalPath)
{
// We guarantee we'll expand short names for paths that only partially exist. As such, we need to find the part of the path that actually does exist. To
// avoid allocating a lot we'll create only one input array and modify the contents with embedded nulls.
Debug.Assert(!PathInternal.IsPartiallyQualified(outputBuilder.AsSpan()), "should have resolved by now");
// We'll have one of a few cases by now (the normalized path will have already:
//
// 1. Dos path (C:\)
// 2. Dos UNC (\\Server\Share)
// 3. Dos device path (\\.\C:\, \\?\C:\)
//
// We want to put the extended syntax on the front if it doesn't already have it (for long path support and speed), which may mean switching from \\.\.
//
// Note that we will never get \??\ here as GetFullPathName() does not recognize \??\ and will return it as C:\??\ (or whatever the current drive is).
int rootLength = PathInternal.GetRootLength(outputBuilder.AsSpan());
bool isDevice = PathInternal.IsDevice(outputBuilder.AsSpan());
// As this is a corner case we're not going to add a stackalloc here to keep the stack pressure down.
var inputBuilder = new ValueStringBuilder();
bool isDosUnc = false;
int rootDifference = 0;
bool wasDotDevice = false;
// Add the extended prefix before expanding to allow growth over MAX_PATH
if (isDevice)
{
// We have one of the following (\\?\ or \\.\)
inputBuilder.Append(outputBuilder.AsSpan());
if (outputBuilder[2] == '.')
{
wasDotDevice = true;
inputBuilder[2] = '?';
}
}
else
{
isDosUnc = !PathInternal.IsDevice(outputBuilder.AsSpan()) && outputBuilder.Length > 1 && outputBuilder[0] == '\\' && outputBuilder[1] == '\\';
rootDifference = PrependDevicePathChars(ref outputBuilder, isDosUnc, ref inputBuilder);
}
rootLength += rootDifference;
int inputLength = inputBuilder.Length;
bool success = false;
int foundIndex = inputBuilder.Length - 1;
while (!success)
{
uint result = Interop.Kernel32.GetLongPathNameW(
ref inputBuilder.GetPinnableReference(terminate: true), ref outputBuilder.GetPinnableReference(), (uint)outputBuilder.Capacity);
// Replace any temporary null we added
if (inputBuilder[foundIndex] == '\0')
{
inputBuilder[foundIndex] = '\\';
}
if (result == 0)
{
// Look to see if we couldn't find the file
int error = Marshal.GetLastWin32Error();
if (error != Interop.Errors.ERROR_FILE_NOT_FOUND && error != Interop.Errors.ERROR_PATH_NOT_FOUND)
{
// Some other failure, give up
break;
}
// We couldn't find the path at the given index, start looking further back in the string.
foundIndex--;
for (; foundIndex > rootLength && inputBuilder[foundIndex] != '\\'; foundIndex--)
{
;
}
if (foundIndex == rootLength)
{
// Can't trim the path back any further
break;
}
else
{
// Temporarily set a null in the string to get Windows to look further up the path
inputBuilder[foundIndex] = '\0';
}
}
else if (result > outputBuilder.Capacity)
{
// Not enough space. The result count for this API does not include the null terminator.
outputBuilder.EnsureCapacity(checked ((int)result));
}
else
{
// Found the path
success = true;
outputBuilder.Length = checked ((int)result);
if (foundIndex < inputLength - 1)
{
// It was a partial find, put the non-existent part of the path back
outputBuilder.Append(inputBuilder.AsSpan(foundIndex, inputBuilder.Length - foundIndex));
}
}
}
// If we were able to expand the path, use it, otherwise use the original full path result
ref ValueStringBuilder builderToUse = ref (success ? ref outputBuilder : ref inputBuilder);