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public GetObjectAtIndex ( int index ) : |
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| index | int | |
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/// <summary>
/// Move the iterator to the next related object, starting "before" the first object.
/// </summary>
/// <remarks>
/// Is a factory for RealmObjects, loading a new one and updating <c>Current</c>.
/// </remarks>
/// <returns>True only if can advance.</returns>
public bool MoveNext()
{
if (_enumeratingResults == null)
{
return(false);
}
++_index;
var rowPtr = _enumeratingResults.GetObjectAtIndex(_index);
if (rowPtr == IntPtr.Zero)
{
Current = (T)(object)null;
return(false);
}
Current = (T)(object)_realm.MakeObject(_schema.Name, rowPtr);
return(true);
}
internal override Expression VisitMethodCall(MethodCallExpression m)
{
if (m.Method.DeclaringType == typeof(Queryable))
{
if (m.Method.Name == nameof(Queryable.Where))
{
Visit(m.Arguments[0]);
var lambda = (LambdaExpression)StripQuotes(m.Arguments[1]);
Visit(lambda.Body);
return(m);
}
if (m.Method.Name == nameof(Queryable.OrderBy))
{
Visit(m.Arguments[0]);
AddSort((LambdaExpression)StripQuotes(m.Arguments[1]), true, true);
return(m);
}
if (m.Method.Name == nameof(Queryable.OrderByDescending))
{
Visit(m.Arguments[0]);
AddSort((LambdaExpression)StripQuotes(m.Arguments[1]), true, false);
return(m);
}
if (m.Method.Name == nameof(Queryable.ThenBy))
{
Visit(m.Arguments[0]);
AddSort((LambdaExpression)StripQuotes(m.Arguments[1]), false, true);
return(m);
}
if (m.Method.Name == nameof(Queryable.ThenByDescending))
{
Visit(m.Arguments[0]);
AddSort((LambdaExpression)StripQuotes(m.Arguments[1]), false, false);
return(m);
}
if (m.Method.Name == nameof(Queryable.Count))
{
RecurseToWhereOrRunLambda(m);
var foundCount = CoreQueryHandle.Count();
return(Expression.Constant(foundCount));
}
if (m.Method.Name == nameof(Queryable.Any))
{
RecurseToWhereOrRunLambda(m);
var foundAny = CoreQueryHandle.FindDirect(_realm.SharedRealmHandle) != IntPtr.Zero;
return(Expression.Constant(foundAny));
}
if (m.Method.Name.StartsWith(nameof(Queryable.First)))
{
RecurseToWhereOrRunLambda(m);
var firstObjectPtr = IntPtr.Zero;
if (OptionalSortDescriptorBuilder == null)
{
firstObjectPtr = CoreQueryHandle.FindDirect(_realm.SharedRealmHandle);
}
else
{
using (ResultsHandle rh = _realm.MakeResultsForQuery(CoreQueryHandle, OptionalSortDescriptorBuilder))
{
firstObjectPtr = rh.GetObjectAtIndex(0);
}
}
if (firstObjectPtr != IntPtr.Zero)
{
return(Expression.Constant(_realm.MakeObject(_metadata, firstObjectPtr)));
}
if (m.Method.Name == nameof(Queryable.First))
{
throw new InvalidOperationException("Sequence contains no matching element");
}
Debug.Assert(m.Method.Name == nameof(Queryable.FirstOrDefault), $"The method {m.Method.Name} is not supported. We expected {nameof(Queryable.FirstOrDefault)}.");
return(Expression.Constant(null));
}
/*
* // FIXME: See discussion in the test DefaultIfEmptyReturnsDefault
* // kept because it shows part of what might be a viable implementation if can work out architectural issues
*
* if (m.Method.Name == nameof(Queryable.DefaultIfEmpty))
* {
* RecurseToWhereOrRunLambda(m);
* IntPtr firstObjectPtr = _coreQueryHandle.FindDirect(IntPtr.Zero);
* if (firstObjectPtr != IntPtr.Zero)
* return m; // as if just a "Where"
* var innerType = m.Type.GetGenericArguments()[0];
* var listType = typeof(List<>).MakeGenericType(innerType);
* var singleNullItemList = Activator.CreateInstance(listType);
* ((IList)singleNullItemList).Add(null);
* return Expression.Constant(singleNullItemList);
* }
*/
if (m.Method.Name.StartsWith(nameof(Queryable.Single))) // same as unsorted First with extra checks
{
RecurseToWhereOrRunLambda(m);
var firstObjectPtr = CoreQueryHandle.FindDirect(_realm.SharedRealmHandle);
if (firstObjectPtr == IntPtr.Zero)
{
if (m.Method.Name == nameof(Queryable.Single))
{
throw new InvalidOperationException("Sequence contains no matching element");
}
Debug.Assert(m.Method.Name == nameof(Queryable.SingleOrDefault), $"The method {m.Method.Name} is not supported. We expected {nameof(Queryable.SingleOrDefault)}.");
return(Expression.Constant(null));
}
var firstObject = Realm.CreateObjectHandle(firstObjectPtr, _realm.SharedRealmHandle);
var nextObjectPtr = CoreQueryHandle.FindNext(firstObject);
if (nextObjectPtr != IntPtr.Zero)
{
throw new InvalidOperationException("Sequence contains more than one matching element");
}
return(Expression.Constant(_realm.MakeObject(_metadata, firstObject)));
}
if (m.Method.Name.StartsWith(nameof(Queryable.Last)))
{
RecurseToWhereOrRunLambda(m);
var lastObjectPtr = IntPtr.Zero;
using (ResultsHandle rh = _realm.MakeResultsForQuery(CoreQueryHandle, OptionalSortDescriptorBuilder))
{
var lastIndex = rh.Count() - 1;
if (lastIndex >= 0)
{
lastObjectPtr = rh.GetObjectAtIndex(lastIndex);
}
}
if (lastObjectPtr != IntPtr.Zero)
{
return(Expression.Constant(_realm.MakeObject(_metadata, lastObjectPtr)));
}
if (m.Method.Name == nameof(Queryable.Last))
{
throw new InvalidOperationException("Sequence contains no matching element");
}
Debug.Assert(m.Method.Name == nameof(Queryable.LastOrDefault), $"The method {m.Method.Name} is not supported. We expected {nameof(Queryable.LastOrDefault)}.");
return(Expression.Constant(null));
}
if (m.Method.Name.StartsWith(nameof(Queryable.ElementAt)))
{
Visit(m.Arguments.First());
object argument;
if (!TryExtractConstantValue(m.Arguments.Last(), out argument) || argument.GetType() != typeof(int))
{
throw new NotSupportedException($"The method '{m.Method}' has to be invoked with a single integer constant argument or closure variable");
}
IntPtr objectPtr;
var index = (int)argument;
if (OptionalSortDescriptorBuilder == null)
{
objectPtr = CoreQueryHandle.FindDirect(_realm.SharedRealmHandle, (IntPtr)index);
}
else
{
using (var rh = _realm.MakeResultsForQuery(CoreQueryHandle, OptionalSortDescriptorBuilder))
{
objectPtr = rh.GetObjectAtIndex(index);
}
}
if (objectPtr != IntPtr.Zero)
{
var objectHandle = Realm.CreateObjectHandle(objectPtr, _realm.SharedRealmHandle);
return(Expression.Constant(_realm.MakeObject(_metadata, objectHandle)));
}
if (m.Method.Name == nameof(Queryable.ElementAt))
{
throw new ArgumentOutOfRangeException();
}
Debug.Assert(m.Method.Name == nameof(Queryable.ElementAtOrDefault), $"The method {m.Method.Name} is not supported. We expected {nameof(Queryable.ElementAtOrDefault)}.");
return(Expression.Constant(null));
}
}
if (m.Method.DeclaringType == typeof(string) ||
m.Method.DeclaringType == typeof(StringExtensions))
{
QueryHandle.Operation <string> queryMethod = null;
// For extension methods, member should be m.Arguments[0] as MemberExpression;
MemberExpression member = null;
// For extension methods, that should be 1
var stringArgumentIndex = 0;
if (m.Method == Methods.String.Contains.Value)
{
queryMethod = (q, c, v) => q.StringContains(c, v, caseSensitive: true);
}
else if (m.Method == Methods.String.ContainsStringComparison.Value)
{
member = m.Arguments[0] as MemberExpression;
stringArgumentIndex = 1;
queryMethod = (q, c, v) => q.StringContains(c, v, GetComparisonCaseSensitive(m));
}
else if (m.Method == Methods.String.StartsWith.Value)
{
queryMethod = (q, c, v) => q.StringStartsWith(c, v, caseSensitive: true);
}
else if (m.Method == Methods.String.StartsWithStringComparison.Value)
{
queryMethod = (q, c, v) => q.StringStartsWith(c, v, GetComparisonCaseSensitive(m));
}
else if (m.Method == Methods.String.EndsWith.Value)
{
queryMethod = (q, c, v) => q.StringEndsWith(c, v, caseSensitive: true);
}
else if (m.Method == Methods.String.EndsWithStringComparison.Value)
{
queryMethod = (q, c, v) => q.StringEndsWith(c, v, GetComparisonCaseSensitive(m));
}
else if (m.Method == Methods.String.IsNullOrEmpty.Value)
{
member = m.Arguments.SingleOrDefault() as MemberExpression;
if (member == null)
{
throw new NotSupportedException($"The method '{m.Method}' has to be invoked with a RealmObject member");
}
var columnIndex = CoreQueryHandle.GetColumnIndex(member.Member.Name);
CoreQueryHandle.GroupBegin();
CoreQueryHandle.NullEqual(columnIndex);
CoreQueryHandle.Or();
CoreQueryHandle.StringEqual(columnIndex, string.Empty, caseSensitive: true);
CoreQueryHandle.GroupEnd();
return(m);
}
else if (m.Method == Methods.String.EqualsMethod.Value)
{
queryMethod = (q, c, v) => q.StringEqual(c, v, caseSensitive: true);
}
else if (m.Method == Methods.String.EqualsStringComparison.Value)
{
queryMethod = (q, c, v) => q.StringEqual(c, v, GetComparisonCaseSensitive(m));
}
else if (m.Method == Methods.String.Like.Value)
{
member = m.Arguments[0] as MemberExpression;
stringArgumentIndex = 1;
object caseSensitive;
if (!TryExtractConstantValue(m.Arguments.Last(), out caseSensitive) || !(caseSensitive is bool))
{
throw new NotSupportedException($"The method '{m.Method}' has to be invoked with a string and boolean constant arguments.");
}
queryMethod = (q, c, v) => q.StringLike(c, v, (bool)caseSensitive);
}
if (queryMethod != null)
{
member = member ?? m.Object as MemberExpression;
if (member == null)
{
throw new NotSupportedException($"The method '{m.Method}' has to be invoked on a RealmObject member");
}
var columnIndex = CoreQueryHandle.GetColumnIndex(member.Member.Name);
object argument;
if (!TryExtractConstantValue(m.Arguments[stringArgumentIndex], out argument) ||
(argument != null && argument.GetType() != typeof(string)))
{
throw new NotSupportedException($"The method '{m.Method}' has to be invoked with a single string constant argument or closure variable");
}
queryMethod(CoreQueryHandle, columnIndex, (string)argument);
return(m);
}
}
throw new NotSupportedException($"The method '{m.Method.Name}' is not supported");
}