/// <summary>Tries to create a key segment for the given filter if it is non empty.</summary>
/// <param name="previous">Segment on which to compose.</param>
/// <param name="parenthesisExpression">Parenthesis expression of segment.</param>
/// <param name="keySegment">The key segment that was created if the key was non-empty.</param>
/// <returns>Whether the key was non-empty.</returns>
internal static bool TryCreateKeySegmentFromParentheses(ODataPathSegment previous, string parenthesisExpression, out ODataPathSegment keySegment)
{
DebugUtils.CheckNoExternalCallers();
Debug.Assert(parenthesisExpression != null, "parenthesisExpression != null");
Debug.Assert(previous != null, "segment!= null");
ExceptionUtil.ThrowSyntaxErrorIfNotValid(!previous.SingleResult);
SegmentArgumentParser key;
ExceptionUtil.ThrowSyntaxErrorIfNotValid(SegmentArgumentParser.TryParseKeysFromUri(parenthesisExpression, out key));
// People/NS.Employees() is OK, just like People() is OK
if (key.IsEmpty)
{
keySegment = null;
return(false);
}
keySegment = CreateKeySegment(previous, key);
return(true);
}
/// <summary>Attempts to parse key values from the specified text.</summary>
/// <param name='text'>Text to parse (not null).</param>
/// <param name="allowNamedValues">Set to true if the parser should accept named values
/// so syntax like Name='value'. If this is false, the parsing will fail on such constructs.</param>
/// <param name="allowNull">Set to true if the parser should accept null values.
/// If set to false, the parser will fail on null values.</param>
/// <param name='instance'>After invocation, the parsed key instance.</param>
/// <returns>
/// true if the key instance was parsed; false if there was a
/// syntactic error.
/// </returns>
/// <remarks>
/// The returned instance contains only string values. To get typed values, a call to
/// TryConvertValues is necessary.
/// </remarks>
private static bool TryParseFromUri(string text, bool allowNamedValues, bool allowNull, out SegmentArgumentParser instance)
{
Debug.Assert(text != null, "text != null");
Dictionary <string, string> namedValues = null;
List <string> positionalValues = null;
ExpressionLexer lexer = new ExpressionLexer(text, true, false);
ExpressionToken currentToken = lexer.CurrentToken;
if (currentToken.Kind == ExpressionTokenKind.End)
{
instance = Empty;
return(true);
}
instance = null;
do
{
if (currentToken.Kind == ExpressionTokenKind.Identifier && allowNamedValues)
{
// Name-value pair.
if (positionalValues != null)
{
// We cannot mix named and non-named values.
return(false);
}
string identifier = lexer.CurrentToken.GetIdentifier();
lexer.NextToken();
if (lexer.CurrentToken.Kind != ExpressionTokenKind.Equal)
{
return(false);
}
lexer.NextToken();
if (!lexer.CurrentToken.IsKeyValueToken)
{
return(false);
}
string namedValue = lexer.CurrentToken.Text;
CreateIfNull(ref namedValues);
if (namedValues.ContainsKey(identifier))
{
// Duplicate name.
return(false);
}
namedValues.Add(identifier, namedValue);
}
else if (currentToken.IsKeyValueToken || (allowNull && currentToken.Kind == ExpressionTokenKind.NullLiteral))
{
// Positional value.
if (namedValues != null)
{
// We cannot mix named and non-named values.
return(false);
}
CreateIfNull(ref positionalValues);
positionalValues.Add(lexer.CurrentToken.Text);
}
else
{
return(false);
}
// Read the next token. We should be at the end, or find
// we have a comma followed by something.
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Kind == ExpressionTokenKind.Comma)
{
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Kind == ExpressionTokenKind.End)
{
// Trailing comma.
return(false);
}
}
}while (currentToken.Kind != ExpressionTokenKind.End);
instance = new SegmentArgumentParser(namedValues, positionalValues, false);
return(true);
}
/// <summary>Attempts to parse nullable values (only positional values, no name-value pairs) from the specified text.</summary>
/// <param name='text'>Text to parse (not null).</param>
/// <param name='instance'>After invocation, the parsed key instance.</param>
/// <returns>
/// true if the given values were parsed; false if there was a
/// syntactic error.
/// </returns>
/// <remarks>
/// The returned instance contains only string values. To get typed values, a call to
/// TryConvertValues is necessary.
/// </remarks>
internal static bool TryParseNullableTokens(string text, out SegmentArgumentParser instance)
{
DebugUtils.CheckNoExternalCallers();
return(TryParseFromUri(text, false /*allowNamedValues*/, true /*allowNull*/, out instance));
}