// adapted from Header serialization code in Http2Connection.cs
private static Memory <byte> HPackEncode(HttpHeaders headers)
{
var buffer = new ArrayBuffer(4);
FillAvailableSpaceWithOnes(buffer);
foreach (KeyValuePair <HeaderDescriptor, string[]> header in headers.GetHeaderDescriptorsAndValues())
{
KnownHeader knownHeader = header.Key.KnownHeader;
if (knownHeader != null)
{
// For all other known headers, send them via their pre-encoded name and the associated value.
WriteBytes(knownHeader.Http2EncodedName);
string separator = null;
if (header.Value.Length > 1)
{
HttpHeaderParser parser = header.Key.Parser;
if (parser != null && parser.SupportsMultipleValues)
{
separator = parser.Separator;
}
else
{
separator = HttpHeaderParser.DefaultSeparator;
}
}
WriteLiteralHeaderValues(header.Value, separator);
}
else
{
// The header is not known: fall back to just encoding the header name and value(s).
WriteLiteralHeader(header.Key.Name, header.Value);
}
}
return(buffer.ActiveMemory);
void WriteBytes(ReadOnlySpan <byte> bytes)
{
if (bytes.Length > buffer.AvailableLength)
{
buffer.EnsureAvailableSpace(bytes.Length);
FillAvailableSpaceWithOnes(buffer);
}
bytes.CopyTo(buffer.AvailableSpan);
buffer.Commit(bytes.Length);
}
void WriteLiteralHeaderValues(string[] values, string separator)
{
int bytesWritten;
while (!HPackEncoder.EncodeStringLiterals(values, separator, buffer.AvailableSpan, out bytesWritten))
{
buffer.EnsureAvailableSpace(buffer.AvailableLength + 1);
FillAvailableSpaceWithOnes(buffer);
}
buffer.Commit(bytesWritten);
}
void WriteLiteralHeader(string name, string[] values)
{
int bytesWritten;
while (!HPackEncoder.EncodeLiteralHeaderFieldWithoutIndexingNewName(name, values, HttpHeaderParser.DefaultSeparator, buffer.AvailableSpan, out bytesWritten))
{
buffer.EnsureAvailableSpace(buffer.AvailableLength + 1);
FillAvailableSpaceWithOnes(buffer);
}
buffer.Commit(bytesWritten);
}
// force issues related to buffer not being zeroed out
void FillAvailableSpaceWithOnes(ArrayBuffer buffer) => buffer.AvailableSpan.Fill(0xff);
}
// adapted from Header serialization code in Http2Connection.cs
private static Memory <byte> HPackEncode(HttpHeaders headers, Encoding?valueEncoding)
{
var buffer = new ArrayBuffer(4);
FillAvailableSpaceWithOnes(buffer);
string[] headerValues = Array.Empty <string>();
foreach (HeaderEntry header in headers.GetEntries())
{
int headerValuesCount = HttpHeaders.GetStoreValuesIntoStringArray(header.Key, header.Value, ref headerValues);
Assert.InRange(headerValuesCount, 0, int.MaxValue);
ReadOnlySpan <string> headerValuesSpan = headerValues.AsSpan(0, headerValuesCount);
KnownHeader knownHeader = header.Key.KnownHeader;
if (knownHeader != null)
{
// For all other known headers, send them via their pre-encoded name and the associated value.
WriteBytes(knownHeader.Http2EncodedName);
string separator = null;
if (headerValuesSpan.Length > 1)
{
HttpHeaderParser parser = header.Key.Parser;
if (parser != null && parser.SupportsMultipleValues)
{
separator = parser.Separator;
}
else
{
separator = HttpHeaderParser.DefaultSeparator;
}
}
WriteLiteralHeaderValues(headerValuesSpan, separator);
}
else
{
// The header is not known: fall back to just encoding the header name and value(s).
WriteLiteralHeader(header.Key.Name, headerValuesSpan);
}
}
return(buffer.ActiveMemory);
void WriteBytes(ReadOnlySpan <byte> bytes)
{
if (bytes.Length > buffer.AvailableLength)
{
buffer.EnsureAvailableSpace(bytes.Length);
FillAvailableSpaceWithOnes(buffer);
}
bytes.CopyTo(buffer.AvailableSpan);
buffer.Commit(bytes.Length);
}
void WriteLiteralHeaderValues(ReadOnlySpan <string> values, string separator)
{
int bytesWritten;
while (!HPackEncoder.EncodeStringLiterals(values, separator, valueEncoding, buffer.AvailableSpan, out bytesWritten))
{
buffer.EnsureAvailableSpace(buffer.AvailableLength + 1);
FillAvailableSpaceWithOnes(buffer);
}
buffer.Commit(bytesWritten);
}
void WriteLiteralHeader(string name, ReadOnlySpan <string> values)
{
int bytesWritten;
while (!HPackEncoder.EncodeLiteralHeaderFieldWithoutIndexingNewName(name, values, HttpHeaderParser.DefaultSeparator, valueEncoding, buffer.AvailableSpan, out bytesWritten))
{
buffer.EnsureAvailableSpace(buffer.AvailableLength + 1);
FillAvailableSpaceWithOnes(buffer);
}
buffer.Commit(bytesWritten);
}
// force issues related to buffer not being zeroed out
void FillAvailableSpaceWithOnes(ArrayBuffer buffer) => buffer.AvailableSpan.Fill(0xff);
}