internal static void SetQuality(ICollection <NameValueHeaderValue> parameters, double?value)
{
Contract.Requires(parameters != null);
var qualityParameter = NameValueHeaderValue.Find(parameters, QualityName);
if (value.HasValue)
{
// Note that even if we check the value here, we can't prevent a user from adding an invalid quality
// value using Parameters.Add(). Even if we would prevent the user from adding an invalid value
// using Parameters.Add() he could always add invalid values using HttpHeaders.AddWithoutValidation().
// So this check is really for convenience to show users that they're trying to add an invalid
// value.
if ((value < 0) || (value > 1))
{
throw new ArgumentOutOfRangeException(nameof(value));
}
var qualityString = ((double)value).ToString("0.0##", NumberFormatInfo.InvariantInfo);
if (qualityParameter != null)
{
qualityParameter.Value = qualityString;
}
else
{
parameters.Add(new NameValueHeaderValue(QualityName, qualityString));
}
}
else
{
// Remove quality parameter
if (qualityParameter != null)
{
parameters.Remove(qualityParameter);
}
}
}
/// <summary>
/// Gets a value indicating whether this <see cref="MediaTypeHeaderValue"/> is a subset of
/// <paramref name="otherMediaType"/>. A "subset" is defined as the same or a more specific media type
/// according to the precedence described in https://www.ietf.org/rfc/rfc2068.txt section 14.1, Accept.
/// </summary>
/// <param name="otherMediaType">The <see cref="MediaTypeHeaderValue"/> to compare.</param>
/// <returns>
/// A value indicating whether this <see cref="MediaTypeHeaderValue"/> is a subset of
/// <paramref name="otherMediaType"/>.
/// </returns>
/// <remarks>
/// For example "multipart/mixed; boundary=1234" is a subset of "multipart/mixed; boundary=1234",
/// "multipart/mixed", "multipart/*", and "*/*" but not "multipart/mixed; boundary=2345" or
/// "multipart/message; boundary=1234".
/// </remarks>
public bool IsSubsetOf(MediaTypeHeaderValue otherMediaType)
{
if (otherMediaType == null)
{
return(false);
}
// PERF: Avoid doing anything here that allocates a substring, this is a very hot path
// for content-negotiation.
var indexOfSlash = _mediaType.IndexOf('/');
// "text/plain" is a subset of "text/plain", "text/*" and "*/*". "*/*" is a subset only of "*/*".
if (string.Compare(
strA: _mediaType,
indexA: 0,
strB: otherMediaType._mediaType,
indexB: 0,
length: indexOfSlash,
comparisonType: StringComparison.OrdinalIgnoreCase) != 0)
{
if (!otherMediaType.MatchesAllTypes)
{
return(false);
}
}
else if (string.Compare(
strA: MediaType,
indexA: indexOfSlash + 1,
strB: otherMediaType._mediaType,
indexB: indexOfSlash + 1, // We know the Type is equal, so the index of '/' is the same in both strings.
length: _mediaType.Length - indexOfSlash,
comparisonType: StringComparison.OrdinalIgnoreCase) != 0)
{
if (!otherMediaType.MatchesAllSubTypes)
{
return(false);
}
}
// "text/plain; charset=utf-8; level=1" is a subset of "text/plain; charset=utf-8". In turn
// "text/plain; charset=utf-8" is a subset of "text/plain".
if (otherMediaType._parameters != null && otherMediaType._parameters.Count != 0)
{
// Make sure all parameters in the potential superset are included locally. Fine to have additional
// parameters locally; they make this one more specific.
foreach (var parameter in otherMediaType._parameters)
{
if (string.Equals(parameter.Name, "q", StringComparison.OrdinalIgnoreCase))
{
// "q" and later parameters are not involved in media type matching. Quoting the RFC: The first
// "q" parameter (if any) separates the media-range parameter(s) from the accept-params.
break;
}
var localParameter = NameValueHeaderValue.Find(_parameters, parameter.Name);
if (localParameter == null)
{
// Not found.
return(false);
}
if (!string.Equals(parameter.Value, localParameter.Value, StringComparison.OrdinalIgnoreCase))
{
return(false);
}
}
}
return(true);
}
