/WCFWebApi/src/System.Net.Http/System/Net/Http/Headers/GenericHeaderParser.cs

using System.Collections;

using System.Diagnostics.Contracts;



namespace System.Net.Http.Headers

{

    internal sealed class GenericHeaderParser : BaseHeaderParser

    {

        private delegate int GetParsedValueLengthDelegate(string value, int startIndex, out object parsedValue);



        #region Parser instances



        internal static readonly HttpHeaderParser HostParser = new GenericHeaderParser(false, ParseHost,

            HeaderUtilities.CaseInsensitiveStringComparer);

        internal static readonly HttpHeaderParser TokenListParser = new GenericHeaderParser(true, ParseTokenList,

            HeaderUtilities.CaseInsensitiveStringComparer);

        internal static readonly HttpHeaderParser SingleValueNameValueWithParametersParser = new GenericHeaderParser(false,

            NameValueWithParametersHeaderValue.GetNameValueWithParametersLength);

        internal static readonly HttpHeaderParser MultipleValueNameValueWithParametersParser = new GenericHeaderParser(true,

            NameValueWithParametersHeaderValue.GetNameValueWithParametersLength);

        internal static readonly HttpHeaderParser SingleValueNameValueParser = new GenericHeaderParser(false, ParseNameValue);

        internal static readonly HttpHeaderParser MultipleValueNameValueParser = new GenericHeaderParser(true, ParseNameValue);

        internal static readonly HttpHeaderParser MailAddressParser = new GenericHeaderParser(false, ParseMailAddress);

        internal static readonly HttpHeaderParser SingleValueProductParser = new GenericHeaderParser(false, ParseProduct);

        internal static readonly HttpHeaderParser MultipleValueProductParser = new GenericHeaderParser(true, ParseProduct);

        internal static readonly HttpHeaderParser RangeConditionParser = new GenericHeaderParser(false, 

            RangeConditionHeaderValue.GetRangeConditionLength);

        internal static readonly HttpHeaderParser SingleValueAuthenticationParser = new GenericHeaderParser(false, 

            AuthenticationHeaderValue.GetAuthenticationLength);

        internal static readonly HttpHeaderParser MultipleValueAuthenticationParser = new GenericHeaderParser(true, 

            AuthenticationHeaderValue.GetAuthenticationLength);

        internal static readonly HttpHeaderParser RangeParser = new GenericHeaderParser(false, 

            RangeHeaderValue.GetRangeLength);

        internal static readonly HttpHeaderParser RetryConditionParser = new GenericHeaderParser(false,

            RetryConditionHeaderValue.GetRetryConditionLength);

        internal static readonly HttpHeaderParser ContentRangeParser = new GenericHeaderParser(false, 

            ContentRangeHeaderValue.GetContentRangeLength);

        internal static readonly HttpHeaderParser ContentDispositionParser = new GenericHeaderParser(false,

            ContentDispositionHeaderValue.GetDispositionTypeLength);

        internal static readonly HttpHeaderParser SingleValueStringWithQualityParser = new GenericHeaderParser(false,

            StringWithQualityHeaderValue.GetStringWithQualityLength);

        internal static readonly HttpHeaderParser MultipleValueStringWithQualityParser = new GenericHeaderParser(true, 

            StringWithQualityHeaderValue.GetStringWithQualityLength);

        internal static readonly HttpHeaderParser SingleValueEntityTagParser = new GenericHeaderParser(false, 

            ParseSingleEntityTag);

        internal static readonly HttpHeaderParser MultipleValueEntityTagParser = new GenericHeaderParser(true, 

            ParseMultipleEntityTags);

        internal static readonly HttpHeaderParser SingleValueViaParser = new GenericHeaderParser(false,

            ViaHeaderValue.GetViaLength);

        internal static readonly HttpHeaderParser MultipleValueViaParser = new GenericHeaderParser(true,

            ViaHeaderValue.GetViaLength);

        internal static readonly HttpHeaderParser SingleValueWarningParser = new GenericHeaderParser(false,

            WarningHeaderValue.GetWarningLength);

        internal static readonly HttpHeaderParser MultipleValueWarningParser = new GenericHeaderParser(true,

            WarningHeaderValue.GetWarningLength);



        #endregion



        private GetParsedValueLengthDelegate getParsedValueLength;

        private IEqualityComparer comparer;



        public override IEqualityComparer Comparer

        {

            get { return comparer; }

        }



        private GenericHeaderParser(bool supportsMultipleValues, GetParsedValueLengthDelegate getParsedValueLength)

            : this(supportsMultipleValues, getParsedValueLength, null)

        {

        }



        private GenericHeaderParser(bool supportsMultipleValues, GetParsedValueLengthDelegate getParsedValueLength,

            IEqualityComparer comparer)

            : base(supportsMultipleValues)

        {

            Contract.Assert(getParsedValueLength != null);



            this.getParsedValueLength = getParsedValueLength;

            this.comparer = comparer;

        }



        protected override int GetParsedValueLength(string value, int startIndex, object storeValue,

            out object parsedValue)

        {

            return getParsedValueLength(value, startIndex, out parsedValue);

        }



        #region Parse methods



        private static int ParseNameValue(string value, int startIndex, out object parsedValue)

        {

            NameValueHeaderValue temp = null;

            int resultLength = NameValueHeaderValue.GetNameValueLength(value, startIndex, out temp);



            parsedValue = temp;

            return resultLength;

        }



        private static int ParseProduct(string value, int startIndex, out object parsedValue)

        {

            ProductHeaderValue temp = null;

            int resultLength = ProductHeaderValue.GetProductLength(value, startIndex, out temp);



            parsedValue = temp;

            return resultLength;

        }



        private static int ParseSingleEntityTag(string value, int startIndex, out object parsedValue)

        {

            EntityTagHeaderValue temp = null;

            parsedValue = null;



            int resultLength = EntityTagHeaderValue.GetEntityTagLength(value, startIndex, out temp);



            // If we don't allow '*' ("Any") as valid ETag value, return false (e.g. 'ETag' header)

            if (temp == EntityTagHeaderValue.Any)

            {

                return 0;

            }



            parsedValue = temp;

            return resultLength;

        }



        // Note that if multiple ETag values are allowed (e.g. 'If-Match', 'If-None-Match'), according to the RFC

        // the value must either be '*' or a list of ETag values. It's not allowed to have both '*' and a list of 

        // ETag values. We're not that strict: We allow both '*' and ETag values in a list. If the server sends such

        // an invalid list, we want to be able to represent it using the corresponding header property.

        private static int ParseMultipleEntityTags(string value, int startIndex, out object parsedValue)

        {

            EntityTagHeaderValue temp = null;

            int resultLength = EntityTagHeaderValue.GetEntityTagLength(value, startIndex, out temp);



            parsedValue = temp;

            return resultLength;

        }



        private static int ParseMailAddress(string value, int startIndex, out object parsedValue)

        {

            parsedValue = null;



            if (HttpRuleParser.ContainsInvalidNewLine(value, startIndex))

            {

                return 0;

            }



            string result = value.Substring(startIndex);



            if (!HeaderUtilities.IsValidEmailAddress(result))

            {

                return 0;

            }



            parsedValue = result;

            return result.Length;

        }



        private static int ParseHost(string value, int startIndex, out object parsedValue)

        {

            string host = null;

            int hostLength = HttpRuleParser.GetHostLength(value, startIndex, false, out host);



            parsedValue = host;

            return hostLength;

        }



        private static int ParseTokenList(string value, int startIndex, out object parsedValue)

        {

            int resultLength = HttpRuleParser.GetTokenLength(value, startIndex);



            parsedValue = value.Substring(startIndex, resultLength);

            return resultLength;

        }



        #endregion

    }

}