simplify visitor for easier extension

influxdata · Jul 13, 2023 · 118a69c · 118a69c
1 parent e5f595b
commit 118a69c
Showing 1 changed file with 34 additions and 60 deletions.
diff --git a/Client.Linq/Internal/QueryExpressionTreeVisitor.cs b/Client.Linq/Internal/QueryExpressionTreeVisitor.cs
@@ -190,75 +190,49 @@ protected override Expression VisitMethodCall(MethodCallExpression expression)
 
             if (expression.Method.DeclaringType == typeof(string))
             {
-                if (expression.Method.Name.Equals("ToLower"))
-                {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new ToLower(part));
-                    return expression;
-                }
-                else if (expression.Method.Name.Equals("ToUpper"))
-                {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new ToUpper(part));
-                    return expression;
-                }
-                else if (expression.Method.Name.Equals("Contains"))
-                {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    partsCount = _expressionParts.Count;
-                    Visit(expression.Arguments[0]);
-                    var part2 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new Contains(part, part2));
-                    return expression;
-                }
-                else if (expression.Method.Name.Equals("StartsWith"))
+                _context.QueryAggregator.AddImport("strings");
+                var partsCount = _expressionParts.Count;
+                Visit(expression.Object);
+                var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
+                IEnumerable<IExpressionPart> part2 = null;
+                IEnumerable<IExpressionPart> part3 = null;
+                if (expression.Arguments.Count > 0)
                 {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
                     partsCount = _expressionParts.Count;
                     Visit(expression.Arguments[0]);
-                    var part2 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new StartsWith(part, part2));
-                    return expression;
+                    part2 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
                 }
-                else if (expression.Method.Name.Equals("EndsWith"))
+
+                if (expression.Arguments.Count > 1)
                 {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
                     partsCount = _expressionParts.Count;
-                    Visit(expression.Arguments[0]);
-                    var part2 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new EndsWith(part, part2));
-                    return expression;
+                    Visit(expression.Arguments[1]);
+                    part3 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
                 }
-                else if (expression.Method.Name.Equals("Replace"))
+
+                switch (expression.Method.Name)
                 {
-                    _context.QueryAggregator.AddImport("strings");
-                    var partsCount = _expressionParts.Count;
-                    Visit(expression.Object);
-                    var part = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    partsCount = _expressionParts.Count;
-                    Visit(expression.Arguments[0]);
-                    var part2 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    partsCount = _expressionParts.Count;
-                    Visit(expression.Arguments[1]);
-                    var part3 = GetAndRemoveExpressionParts(partsCount, _expressionParts.Count);
-                    _expressionParts.Add(new Replace(part, part2, part3));
-                    return expression;
+                    case "ToLower":
+                        _expressionParts.Add(new ToLower(part));
+                        return expression;
+                    case "ToUpper":
+                        _expressionParts.Add(new ToUpper(part));
+                        return expression;
+                    case "Contains":
+                        _expressionParts.Add(new Contains(part, part2));
+                        return expression;
+                    case "StartsWith":
+                        _expressionParts.Add(new StartsWith(part, part2));
+                        return expression;
+                    case "EndsWith":
+                        _expressionParts.Add(new EndsWith(part, part2));
+                        return expression;
+                    case "Replace":
+                        _expressionParts.Add(new Replace(part, part2, part3));
+                        return expression;
                 }
+
+                throw new NotSupportedException(expression.Method.Name + " of String class is not yet supported.");
             }
 
             if (expression.Method.Name.Equals("ToString"))