public static ContinuationTableEntry FromEntity(Type entity)
{
ContinuationTableEntry entry = new ContinuationTableEntry();
entry.Type = ContinuationType.Entity;
entry.Entity = entity;
return(entry);
}
public static ContinuationTableEntry FromProperty(PropertyInfo property, FieldAttribute field)
{
ContinuationTableEntry entry = new ContinuationTableEntry();
entry.Type = ContinuationType.Property;
entry.Property = property;
entry.FieldAttribute = field;
return(entry);
}
public static ContinuationTableEntry FromLookup(PropertyInfo property, FieldAttribute field, PropertyInfo childProperty, FieldAttribute childField)
{
ContinuationTableEntry entry = new ContinuationTableEntry();
entry.Type = ContinuationType.Lookup;
entry.Property = property;
entry.FieldAttribute = field;
entry.Lookup = new ContinuationTableLookupEntry()
{
FieldAttribute = childField, Property = childProperty
};
return(entry);
}
private Type BuildContinuationTable(ParameterExpression p, Expression ex, ContinuationTable table)
{
//
// Only anonymous type creations can cause valid continuations.
//
NewExpression ne = ex as NewExpression;
if (ne != null && IsAnonymousType(ne.Constructor.DeclaringType))
{
Type t = ne.Constructor.DeclaringType;
//
// Check for arguments that are just aliases for the entity or an entity property.
//
for (int i = 0; i < ne.Arguments.Count; i++)
{
MemberExpression me;
//
// Get the rhs and lhs of new { <name := lhs> = <arg := rhs> }.
//
Expression arg = ne.Arguments[i];
string name = ne.Members[i].Name.Substring("get_".Length);
PropertyInfo prop = t.GetProperty(name);
//
// Keep reference to the entity itself, or deal with continuation.
//
if (arg == p)
{
if (_continuationTable == null)
{
table.Add(prop, ContinuationTableEntry.FromEntity(_results.EntityType));
}
else
{
//
// Merge tables because there's a reference to the previous continuation type, so all original mappings are still available.
//
foreach (PropertyInfo key in _continuationTable.Keys)
{
if (!table.ContainsKey(key))
{
table.Add(key, _continuationTable[key]);
}
}
}
}
//
// Find recursive case.
//
else if (arg is NewExpression)
{
BuildContinuationTable(p, arg, table);
}
//
// Find reference to entity property.
//
else if ((me = arg as MemberExpression) != null)
{
//
// For continuations, check whether the target is already in the table. If so, copy to the new table.
// This will also take care of deep copies of nested continuations if one is referred to.
//
if (_continuationTable != null)
{
//
// Check for raw reference.
//
PropertyInfo tgt = me.Member as PropertyInfo;
if (tgt != null && _continuationTable.ContainsKey(tgt))
{
table.Add(prop, _continuationTable[tgt]);
continue;
}
//
// Check for reference to anonymous type.
//
if (IsAnonymousType(tgt.PropertyType))
{
//
// Check in dictionary of continuations.
//
if (_continuationTables.ContainsKey(tgt.PropertyType))
{
//
// Merge tables.
//
foreach (PropertyInfo key in _continuationTables[tgt.PropertyType].Keys)
{
if (!table.ContainsKey(key))
{
table.Add(key, _continuationTables[tgt.PropertyType][key]);
}
}
}
//
// New nested anonymous type.
//
else
{
Queue <Type> q = new Queue <Type>();
q.Enqueue(tgt.PropertyType);
while (q.Count > 0)
{
foreach (PropertyInfo pi in q.Dequeue().GetProperties())
{
//
// Recursive case.
//
if (IsAnonymousType(pi.PropertyType))
{
q.Enqueue(pi.PropertyType);
}
//
// Copy in existing references; the same key could already be present.
//
else if (_continuationTable.ContainsKey(pi) && !table.ContainsKey(pi))
{
table.Add(pi, _continuationTable[pi]);
}
}
}
}
}
}
FieldAttribute fa;
PropertyInfo target = FindEntityProperty(me, out fa);
if (target != null)
{
//
// Reference to entity property on the entity itself.
//
if (target.DeclaringType == _results.EntityType)
{
table.Add(prop, ContinuationTableEntry.FromProperty(target, fa));
}
//
// Lookup(Multi) fields can refer to another entity's property.
//
else
{
//
// Variables me2 and fa2 will refer to the parent of the current expression, which should be a lookup field on the root entity.
//
MemberExpression me2 = me.Expression as MemberExpression;
if (me2 != null)
{
//
// The lookup field could be referenced through a field on the previous continuation. Check for this situation.
//
if (_continuationTable != null)
{
PropertyInfo tgt2 = me2.Member as PropertyInfo;
ContinuationTableEntry el;
if (tgt2 != null && _continuationTable.TryGetValue(tgt2, out el) && el.Type == ContinuationType.Property && el.Property.DeclaringType == _results.EntityType)
{
table.Add(prop, ContinuationTableEntry.FromLookup(el.Property, el.FieldAttribute, target, fa));
continue;
}
}
FieldAttribute fa2;
PropertyInfo target2 = FindEntityProperty(me2, out fa2);
if (target2 != null && target2.DeclaringType == _results.EntityType)
{
table.Add(prop, ContinuationTableEntry.FromLookup(target2, fa2, target, fa));
}
}
}
}
}
}
return(ne.Constructor.DeclaringType);
}
else
{
return(null);
}
}