// // Resolves into either baseUri or relativeUri according to conditions OR if not possible it uses newUriString // to return combined URI strings from both Uris // otherwise if e != null on output the operation has failed // internal static Uri?ResolveHelper(Uri baseUri, Uri?relativeUri, ref string?newUriString, ref bool userEscaped) { Debug.Assert(!baseUri.IsNotAbsoluteUri && !baseUri.UserDrivenParsing, "Uri::ResolveHelper()|baseUri is not Absolute or is controlled by User Parser."); string relativeStr; if (relativeUri is not null) { if (relativeUri.IsAbsoluteUri) { return(relativeUri); } relativeStr = relativeUri.OriginalString; userEscaped = relativeUri.UserEscaped; } else { relativeStr = string.Empty; } // Here we can assert that passed "relativeUri" is indeed a relative one if (relativeStr.Length > 0 && (UriHelper.IsLWS(relativeStr[0]) || UriHelper.IsLWS(relativeStr[relativeStr.Length - 1]))) { relativeStr = relativeStr.Trim(UriHelper.s_WSchars); } if (relativeStr.Length == 0) { newUriString = baseUri.GetParts(UriComponents.AbsoluteUri, baseUri.UserEscaped ? UriFormat.UriEscaped : UriFormat.SafeUnescaped); return(null); } // Check for a simple fragment in relative part if (relativeStr[0] == '#' && !baseUri.IsImplicitFile && baseUri.Syntax !.InFact(UriSyntaxFlags.MayHaveFragment)) { newUriString = baseUri.GetParts(UriComponents.AbsoluteUri & ~UriComponents.Fragment, UriFormat.UriEscaped) + relativeStr; return(null); } // Check for a simple query in relative part if (relativeStr[0] == '?' && !baseUri.IsImplicitFile && baseUri.Syntax !.InFact(UriSyntaxFlags.MayHaveQuery)) { newUriString = baseUri.GetParts(UriComponents.AbsoluteUri & ~UriComponents.Query & ~UriComponents.Fragment, UriFormat.UriEscaped) + relativeStr; return(null); } // Check on the DOS path in the relative Uri (a special case) if (relativeStr.Length >= 3 && (relativeStr[1] == ':' || relativeStr[1] == '|') && UriHelper.IsAsciiLetter(relativeStr[0]) && (relativeStr[2] == '\\' || relativeStr[2] == '/')) { if (baseUri.IsImplicitFile) { // It could have file:/// prepended to the result but we want to keep it as *Implicit* File Uri newUriString = relativeStr; return(null); } else if (baseUri.Syntax !.InFact(UriSyntaxFlags.AllowDOSPath)) { // The scheme is not changed just the path gets replaced string prefix; if (baseUri.InFact(Flags.AuthorityFound)) { prefix = baseUri.Syntax.InFact(UriSyntaxFlags.PathIsRooted) ? ":///" : "://"; } else { prefix = baseUri.Syntax.InFact(UriSyntaxFlags.PathIsRooted) ? ":/" : ":"; } newUriString = baseUri.Scheme + prefix + relativeStr; return(null); } // If we are here then input like "http://host/path/" + "C:\x" will produce the result http://host/path/c:/x } GetCombinedString(baseUri, relativeStr, userEscaped, ref newUriString); if (ReferenceEquals(newUriString, baseUri._string)) { return(baseUri); } return(null); }