/// <summary>
/// Reads a token or token=(token|quoted-string) from the <paramref name="lexer"/>, convert it to a key value pair and advances the <paramref name="lexer"/>.
/// </summary>
/// <param name="lexer">The lexer to read from.</param>
/// <returns>The converted key value pair.</returns>
private static KeyValuePair<string, string> ReadKeyValuePair(ref HttpHeaderValueLexer lexer)
{
Debug.Assert(lexer.Type == HttpHeaderValueItemType.Token, "lexer.Type == HttpHeaderValueItemType.Token");
string name = lexer.OriginalText;
string value = null;
lexer = lexer.ReadNext();
if (lexer.Type == HttpHeaderValueItemType.ValueSeparator)
{
lexer = lexer.ReadNext();
Debug.Assert(
lexer.Type == HttpHeaderValueItemType.Token || lexer.Type == HttpHeaderValueItemType.QuotedString,
"lexer.Type == HttpHeaderValueItemType.Token || lexer.Type == HttpHeaderValueItemType.QuotedString");
value = lexer.OriginalText;
lexer = lexer.ReadNext();
}
Debug.Assert(
lexer.Type == HttpHeaderValueItemType.End || lexer.Type == HttpHeaderValueItemType.ElementSeparator || lexer.Type == HttpHeaderValueItemType.ParameterSeparator,
"lexer.Type == HttpHeaderValueItemType.End || lexer.Type == HttpHeaderValueItemType.ElementSeparator || lexer.Type == HttpHeaderValueItemType.ParameterSeparator");
return new KeyValuePair<string, string>(name, value);
}
/// <summary>
/// Parses the current preference values to a dictionary of preference and value pairs.
/// </summary>
/// <returns>Returns a dictionary of preference and value pairs; null if the preference header has not been set.</returns>
private HttpHeaderValue ParsePreferences()
{
string preferenceHeaderValue = this.message.GetHeader(this.preferenceHeaderName);
HttpHeaderValueLexer preferenceHeaderLexer = HttpHeaderValueLexer.Create(this.preferenceHeaderName, preferenceHeaderValue);
return preferenceHeaderLexer.ToHttpHeaderValue();
}
/// <summary>
/// Reads a <see cref="HttpHeaderValueElement"/> from <paramref name="lexer"/> and advances the <paramref name="lexer"/> forward.
/// </summary>
/// <param name="lexer">The lexer to read from.</param>
/// <returns>The <see cref="HttpHeaderValueElement"/> that was read.</returns>
private static HttpHeaderValueElement ReadHttpHeaderValueElement(ref HttpHeaderValueLexer lexer)
{
Debug.Assert(lexer.Type == HttpHeaderValueItemType.Token, "lexer.Type == HttpHeaderValueItemType.Token");
List<KeyValuePair<string, string>> keyValuePairs = new List<KeyValuePair<string, string>> { ReadKeyValuePair(ref lexer) };
while (lexer.Type == HttpHeaderValueItemType.ParameterSeparator)
{
lexer = lexer.ReadNext();
keyValuePairs.Add(ReadKeyValuePair(ref lexer));
}
Debug.Assert(
lexer.Type == HttpHeaderValueItemType.ElementSeparator || lexer.Type == HttpHeaderValueItemType.End,
"lexer.Type == HttpHeaderValueItemType.ElementSeparator || lexer.Type == HttpHeaderValueItemType.End");
return new HttpHeaderValueElement(keyValuePairs[0].Key, keyValuePairs[0].Value, keyValuePairs.Skip(1).ToArray());
}