//public static Type ParseType(this IParser parser, IEnumerable<string> namespaces, bool throwException)
//{
// var tmpToken = parser.Token();
// string typeName = parser.Token().GetIdentifier();
// parser.NextToken();
// string methodName = null;
// if (parser.Token().Identity == TokenId.Dot)
// {
// parser.NextToken();
// methodName = parser.Token().Text;
// parser.NextToken();
// }
// while (parser.Token().Identity == TokenId.Dot)
// {
// parser.NextToken();
// typeName = typeName + "." + methodName;
// methodName = parser.Token().GetIdentifier();
// parser.NextToken();
// }
// if(parser.Token().Identity != TokenId.OpenParen)
// {
// typeName = typeName + "." + methodName;
// methodName = null;
// }
// if (namespaces == null)
// namespaces = new string[0];
// var objectType = new TypeFinder(namespaces).FindType(typeName);
// if (objectType != null)
// return objectType;
// if (throwException)
// throw Error.CannotResolveNameToType(tmpToken, typeName);
// parser.TokenCursor.MoveTo(tmpToken.Position);
// return null;
//}
#endregion
private static Expression ParseMethodAccess(this IParser parser, Type type, Expression instance, string methodName)
{
Expression[] args = null;
Func <Expression[]> getArgs = delegate()
{
args = parser.ParseArgumentList();
return(args);
};
var errorPos = parser.Token().Position;
MethodBase mb;
var methodsCount = ExpressionUtility.FindMethod(type, methodName, instance == null, getArgs, out mb);
switch (methodsCount)
{
case 0:
return(null);
//throw Error.ParseError(errorPos, Res.NoApplicableMethod, methodName, TypeUtility.GetTypeName(type));
case 1:
MethodInfo method = (MethodInfo)mb;
if (method.ReturnType == typeof(void))
{
throw Error.ParseError(errorPos, Res.MethodIsVoid, methodName, TypeUtility.GetTypeName(method.DeclaringType));
}
Debug.Assert(args != null);
return(Expression.Call(instance, (MethodInfo)method, args));
default:
throw Error.ParseError(errorPos, Res.AmbiguousMethodInvocation, methodName, TypeUtility.GetTypeName(type));
}
}
IQueryable IQueryProvider.CreateQuery(Expression expression)
{
var elementType = ExpressionUtility.ElementType(expression);
var queryable = CreateQuery(expression, elementType);
return(queryable);
}
public static Expression ParseConstructor(this IParser parser, IEnumerable <string> namespaces)
{
var tmpToken = parser.Token();
var className = parser.Token().Text;
parser.NextToken();
while (parser.Token().Identity == TokenId.Dot)
{
parser.NextToken();
className = className + "." + parser.Token().Text;
parser.NextToken();
}
var objectType = new TypeFinder().FindType(className, namespaces);
if (objectType != null)
{
if (parser.Token().Identity != TokenId.OpenParen && parser.Token().Identity != TokenId.OpenCurlyBrace)
{
throw Error.Token1OrToken2Expected(parser.Token(), "(", "{");
}
Expression[] args = new Expression[0];
//if (objectType != null)
//{
if (parser.Token().Identity == TokenId.OpenParen)
{
args = parser.ParseArgumentList();
}
var cons = ExpressionUtility.FindConstructor(objectType, args);
if (cons == null)
{
throw Error.CanNotFindConstructor(parser.Token(), objectType, args.Select(o => o.Type).ToArray());
}
var newExpr = Expression.New(cons, args);
if (parser.Token().Identity == TokenId.OpenCurlyBrace)
{
var expr = parser.ParseMemberInit(newExpr);
return(expr);
}
return(newExpr);
}
parser.TokenCursor.MoveTo(tmpToken.Position);
return(null);
}
protected override Expression VisitMethodCall(MethodCallExpression m)
{
var anonymousType = typeof(DataRow);
if (m.Method.Name == "Cast")
{
var castSourceType = ExpressionUtility.ElementType(m.Arguments[0]);
var castTargetType = ExpressionUtility.ElementType(m);
if (castTargetType.IsAssignableFrom(anonymousType))
{
this.typePaires.Add(castSourceType, castTargetType);
}
}
return(base.VisitMethodCall(m));
}
public static int FindIndexer(Type type, Expression[] args, out MethodBase method)
{
foreach (Type t in SelfAndBaseTypes(type))
{
MemberInfo[] members = t.GetMembers();//t.GetDefaultMembers();
if (members.Length != 0)
{
IEnumerable <MethodBase> methods = members.
OfType <PropertyInfo>().
Select(p => (MethodBase)p.GetGetMethod()).
Where(m => m != null);
int count = ExpressionUtility.FindBestMethod(methods, args, out method);
if (count != 0)
{
return(count);
}
}
}
method = null;
return(0);
}
TResult IQueryProvider.Execute <TResult>(Expression expression)
{
expression = UpdateExpression(expression);
var isSingleValue = !typeof(IEnumerable).IsAssignableFrom(expression.Type) || expression.Type == typeof(string);
if (isSingleValue)
{
var obj = this.source.Execute <TResult>(expression);
return(obj);
}
var castSourceType = ExpressionUtility.ElementType(expression);
var castTargetType = GetElementType(typeof(TResult));
if (castSourceType != castTargetType)
{
expression = Expression.Call(typeof(Queryable), "Cast", new[] { castTargetType }, expression);
}
var items = this.source.Execute <TResult>(expression);
return(items);
}
static DataContext GetDataContext(IQueryable source)
{
var dc = ExpressionUtility.FindContext(source.Expression);
return(dc);
}
public Parser(IQueryable source, string predicate, params object[] parameters)
: base(GetDataContext(source), predicate, ConvertToObjectParameters(parameters))
{
p = ExpressionUtility.CreateParameter(source.ElementType);
this.source = source;
}
protected override Expression VisitMethodCall(MethodCallExpression m)
{
//==============================================================
// 说明：将索引器字段转换为类的属性或字段
if (m.Method.Name == "get_Item" && m.Object != null && m.Object.Type == this.oldType)
{
Debug.Assert(m.Arguments.Count == 1);
var arg = m.Arguments[0];
Debug.Assert(arg.NodeType == ExpressionType.Constant);
Debug.Assert(arg.Type == typeof(string));
var name = (string)((ConstantExpression)arg).Value;
var pf = TypeUtility.FindPropertyOrField(this.newType, name, false);
if (pf == null)
{
throw Error.NoPublicPropertyOrField(name, newType);
}
Expression expr = Expression.MakeMemberAccess(this.parameter, pf);
if (m.Type != expr.Type)
{
expr = Expression.Convert(expr, m.Type);
}
return(expr);
}
//==============================================================
//==============================================================
// 说明：如果序列的实际类型与 Cast 的目标类型一致，则直接返回序列，而不进行转换。
// 例如：
// var q = db.CreateQuery("select p from Products as p").Cast<Product>();
// 由于序列的实际类型即是Product，因为，Cast 是多余的，直接除。即变为：
// db.CreateQuery("select p from Products as p")
//--------------------------------------------------------------
if (m.Method.Name == "Cast")
{
var castSourceType = ExpressionUtility.ElementType(m.Arguments[0]);
var castTargetType = ExpressionUtility.ElementType(m);
if (this.newType == castSourceType && this.oldType == castTargetType)
{
return(m.Arguments[0]);
}
}
//==============================================================
Expression instance = Visit(m.Object);
IEnumerable <Expression> arguments = VisitExpressionList(m.Arguments);
if ((instance == m.Object) && (arguments == m.Arguments))
{
return(m);
}
//==============================================================
// 说明：替换掉原来的类型
// 例如：
// var q = db.CreateQuery<IDataRecord>("select p from Products as p")
// 变为
// q = db.CreateQuery<Product>()
if (m.Method.IsGenericMethod)
{
var argTypes = m.Method.GetGenericArguments();
if (argTypes[0] == oldType)
{
var methodName = m.Method.Name;
var declareType = m.Method.DeclaringType;
argTypes[0] = newType;
var expr = Expression.Call(declareType, methodName, argTypes, arguments.ToArray());
return(expr);
}
}
//==============================================================
return(Expression.Call(instance, m.Method, arguments));
}
public ActualTypeReplacer(Type oldType, Type newType)
{
this.newType = newType;
this.oldType = oldType;
this.parameter = ExpressionUtility.CreateParameter(newType);
}
