Negative header ids should be valid
[mono.git] / mcs / mcs / support.cs
index 4cba731c3b6249cc19eb89e9799b5f65e2c17f94..d4e018c32594ad118a57c80cd32f675943c470d3 100644 (file)
 //
 // Author:
 //   Miguel de Icaza (miguel@ximian.com)
+//   Marek Safar (marek.safar@gmail.com)
 //
-// (C) 2001 Ximian, Inc (http://www.ximian.com)
+// Copyright 2001 Ximian, Inc (http://www.ximian.com)
+// Copyright 2003-2009 Novell, Inc
+// Copyright 2011 Xamarin Inc
 //
 
 using System;
 using System.IO;
 using System.Text;
-using System.Reflection;
-using System.Collections;
-using System.Reflection.Emit;
-using System.Globalization;
+using System.Collections.Generic;
 
 namespace Mono.CSharp {
 
-       public interface ParameterData {
-               Type ParameterType (int pos);
-               Type [] Types { get; }
-               int  Count { get; }
-               Type ExtensionMethodType { get; }
-               bool HasParams { get; }
-               string ParameterName (int pos);
-               string ParameterDesc (int pos);
-
-               Parameter.Modifier ParameterModifier (int pos);
-               string GetSignatureForError ();
-
-#if MS_COMPATIBLE
-               ParameterData InflateTypes (Type[] genArguments, Type[] argTypes);
-#endif
-       }
-
-       public class ReflectionParameters : ParameterData {
-               ParameterInfo [] pi;
-               Type [] types;
-               int params_idx = -1;
-               bool is_varargs;
-               bool is_extension;
-               ParameterData gpd;
-
-               public ReflectionParameters (MethodBase mb)
-               {
-                       ParameterInfo [] pi = mb.GetParameters ();
-                       is_varargs = (mb.CallingConvention & CallingConventions.VarArgs) != 0;
-
-                       this.pi = pi;
-                       int count = pi.Length;
-
-                       if (count == 0) {
-                               types = Type.EmptyTypes;
-                               return;
-                       }
-
-                       types = new Type [count];
-                       for (int i = 0; i < count; i++)
-                               types [i] = pi [i].ParameterType;
-
-                       // TODO: This (if) should be done one level higher to correctly use
-                       // out caching facilities.
-                       MethodBase generic = TypeManager.DropGenericMethodArguments (mb);
-                       if (generic != mb) {
-                               gpd = TypeManager.GetParameterData (generic);
-                               if (gpd.HasParams) {
-                                       for (int i = gpd.Count; i != 0; --i) {
-                                               if ((gpd.ParameterModifier (i-1) & Parameter.Modifier.PARAMS) != 0) {
-                                                       this.params_idx = i-1;
-                                                       break;
-                                               }
-                                       }
-                               }
-                               return;
-                       }
-
-                       //
-                       // So far, the params attribute can be used in C# for the last
-                       // and next to last method parameters.
-                       // If some other language can place it anywhere we will
-                       // have to analyze all parameters and not just last 2.
-                       //
-                       --count;
-                       for (int i = count; i >= 0 && i > count - 2; --i) {
-                               if (!pi [i].ParameterType.IsArray)
-                                       continue;
-
-                               if (pi [i].IsDefined (TypeManager.param_array_type, false)) {
-                                       params_idx = i;
-                                       break;
-                               }
-                       }
-
-                       if (TypeManager.extension_attribute_type != null && mb.IsStatic &&
-                               (mb.DeclaringType.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
-                               mb.IsDefined (TypeManager.extension_attribute_type, false))
-                               is_extension = true;
-               }
+       sealed class ReferenceEquality<T> : IEqualityComparer<T> where T : class
+       {
+               public static readonly IEqualityComparer<T> Default = new ReferenceEquality<T> ();
 
-               public override bool Equals (object obj)
+               private ReferenceEquality ()
                {
-                       ReflectionParameters rp = obj as ReflectionParameters;
-                       if (rp == null)
-                               return false;
-
-                       if (Count != rp.Count)
-                               return false;
-
-                       for (int i = 0; i < Count; ++i) {
-                       if (!types [i].Equals (rp.types [i]))
-                               return false;
-                       }
-                       return true;
                }
 
-               public override int GetHashCode ()
+               public bool Equals (T x, T y)
                {
-                       return base.GetHashCode ();
+                       return ReferenceEquals (x, y);
                }
 
-               public string GetSignatureForError ()
+               public int GetHashCode (T obj)
                {
-                       StringBuilder sb = new StringBuilder ("(");
-                       for (int i = 0; i < pi.Length; ++i) {
-                               if (i != 0)
-                                       sb.Append (", ");
-                               sb.Append (ParameterDesc (i));
-                       }
-                       if (is_varargs) {
-                               if (pi.Length > 0)
-                                       sb.Append (", ");
-                               sb.Append ("__arglist");
-                       }
-                       sb.Append (')');
-                       return sb.ToString ();
+                       return System.Runtime.CompilerServices.RuntimeHelpers.GetHashCode (obj);
                }
-
-#if MS_COMPATIBLE
-               public ParameterData InflateTypes (Type[] genArguments, Type[] argTypes)
+       }
+#if !NET_4_0 && !MONODROID
+       public class Tuple<T1, T2> : IEquatable<Tuple<T1, T2>>
+       {
+               public Tuple (T1 item1, T2 item2)
                {
-                       ReflectionParameters p = (ReflectionParameters)MemberwiseClone ();
-
-                       for (int i = 0; i < types.Length; ++i) {
-                               if (types[i].IsGenericParameter) {
-                                       for (int ii = 0; ii < genArguments.Length; ++ii) {
-                                               if (types[i] != genArguments[ii])
-                                                       continue;
-
-                                               p.types[i] = argTypes[ii];
-                                               break;
-                                       }
-                                       continue;
-                               }
-                               
-                               if (types[i].IsGenericType) {
-                                       Type[] gen_arguments_open = types[i].GetGenericTypeDefinition ().GetGenericArguments ();
-                                       Type[] gen_arguments = types[i].GetGenericArguments ();
-                                       for (int ii = 0; ii < gen_arguments_open.Length; ++ii) {
-                                               if (gen_arguments [ii].IsGenericParameter) {
-                                                       for (int iii = 0; iii < genArguments.Length; ++iii) {
-                                                               if (gen_arguments [ii] != genArguments [iii])
-                                                                       continue;
-
-                                                               gen_arguments_open [ii] = argTypes [iii];
-                                                               break;
-                                                       }
-                                               } else {
-                                                       gen_arguments_open [ii] = gen_arguments [ii];
-                                               }
-                                       }
-
-                                       p.types[i] = types[i].GetGenericTypeDefinition ().MakeGenericType (gen_arguments_open);
-                               }
-                       }
-                       return p;
+                       Item1 = item1;
+                       Item2 = item2;
                }
-#endif
 
-               public Type ParameterType (int pos)
-               {
-                       if (is_varargs && pos >= pi.Length)
-                               return TypeManager.runtime_argument_handle_type;
-
-                       return types [pos];
-               }
+               public T1 Item1 { get; private set; }
+               public T2 Item2 { get; private set; }
 
-               public string ParameterName (int pos)
+               public override int GetHashCode ()
                {
-                       if (gpd != null)
-                               return gpd.ParameterName (pos);
-
-                       if (is_varargs && pos >= pi.Length)
-                               return "__arglist";
-
-                       return pi [pos].Name;
+                       return Item1.GetHashCode () ^ Item2.GetHashCode ();
                }
 
-               public string ParameterDesc (int pos)
-               {
-                       if (is_varargs && pos >= pi.Length)
-                               return "";
-
-                       StringBuilder sb = new StringBuilder ();
-
-                       if (pi [pos].IsIn)
-                               sb.Append ("in ");
-
-                       Type partype = ParameterType (pos);
-                       if (partype.IsByRef){
-                               partype = TypeManager.GetElementType (partype);
-                               if (pi [pos].IsOut)
-                                       sb.Append ("out ");
-                               else
-                                       sb.Append ("ref ");
-                       }
-
-                       if (params_idx == pos)
-                               sb.Append ("params ");
+               #region IEquatable<Tuple<T1,T2>> Members
 
-                       if (pos == 0 && ExtensionMethodType != null)
-                               sb.Append ("this ");
-
-                       sb.Append (TypeManager.CSharpName (partype).Replace ("&", ""));
-
-                       return sb.ToString ();
-               }
-
-               public Parameter.Modifier ParameterModifier (int pos)
+               public bool Equals (Tuple<T1, T2> other)
                {
-                       if (pos == params_idx)
-                               return Parameter.Modifier.PARAMS;
-                       else if (is_varargs && pos >= pi.Length)
-                               return Parameter.Modifier.ARGLIST;
-
-                       if (gpd != null)
-                               return gpd.ParameterModifier (pos);
-
-                       Type t = types [pos];
-                       if (t.IsByRef){
-                               if ((pi [pos].Attributes & (ParameterAttributes.Out|ParameterAttributes.In)) == ParameterAttributes.Out)
-                                       return Parameter.Modifier.OUT;
-                               else
-                                       return Parameter.Modifier.REF;
-                       }
-
-                       return Parameter.Modifier.NONE;
-               }
-
-               public int Count {
-                       get { return is_varargs ? pi.Length + 1 : pi.Length; }
-               }
-
-               public Type ExtensionMethodType {
-                       get {
-                               if (!is_extension)
-                                       return null;
-
-                               return types [0];
-                       }
+                       return EqualityComparer<T1>.Default.Equals (Item1, other.Item1) &&
+                               EqualityComparer<T2>.Default.Equals (Item2, other.Item2);
                }
 
-               public bool HasParams {
-                       get { return params_idx != -1; }
-               }
-
-               public Type[] Types {
-                       get { return types; }
-               }
+               #endregion
        }
 
-#if GMCS_SOURCE
-       public class ReflectionConstraints : GenericConstraints
+       public class Tuple<T1, T2, T3> : IEquatable<Tuple<T1, T2, T3>>
        {
-               GenericParameterAttributes attrs;
-               Type base_type;
-               Type class_constraint;
-               Type[] iface_constraints;
-               string name;
-
-               public static GenericConstraints GetConstraints (Type t)
-               {
-                       Type [] constraints = t.GetGenericParameterConstraints ();
-                       GenericParameterAttributes attrs = t.GenericParameterAttributes;
-                       if (constraints.Length == 0 && attrs == GenericParameterAttributes.None)
-                               return null;
-                       return new ReflectionConstraints (t.Name, constraints, attrs);
-               }
-
-               private ReflectionConstraints (string name, Type [] constraints, GenericParameterAttributes attrs)
+               public Tuple (T1 item1, T2 item2, T3 item3)
                {
-                       this.name = name;
-                       this.attrs = attrs;
-
-                       if ((constraints.Length > 0) && !constraints [0].IsInterface) {
-                               class_constraint = constraints [0];
-                               iface_constraints = new Type [constraints.Length - 1];
-                               Array.Copy (constraints, 1, iface_constraints, 0, constraints.Length - 1);
-                       } else
-                               iface_constraints = constraints;
-
-                       if (HasValueTypeConstraint)
-                               base_type = TypeManager.value_type;
-                       else if (class_constraint != null)
-                               base_type = class_constraint;
-                       else
-                               base_type = TypeManager.object_type;
-               }
-
-               public override string TypeParameter {
-                       get { return name; }
-               }
-
-               public override GenericParameterAttributes Attributes {
-                       get { return attrs; }
-               }
-
-               public override Type ClassConstraint {
-                       get { return class_constraint; }
-               }
-
-               public override Type EffectiveBaseClass {
-                       get { return base_type; }
+                       Item1 = item1;
+                       Item2 = item2;
+                       Item3 = item3;
                }
 
-               public override Type[] InterfaceConstraints {
-                       get { return iface_constraints; }
-               }
-       }
-#endif
-
-       class PtrHashtable : Hashtable {
-               sealed class PtrComparer : IComparer {
-                       private PtrComparer () {}
+               public T1 Item1 { get; private set; }
+               public T2 Item2 { get; private set; }
+               public T3 Item3 { get; private set; }
 
-                       public static PtrComparer Instance = new PtrComparer ();
-
-                       public int Compare (object x, object y)
-                       {
-                               if (x == y)
-                                       return 0;
-                               else
-                                       return 1;
-                       }
-               }
-
-               public PtrHashtable ()
+               public override int GetHashCode ()
                {
-                       comparer = PtrComparer.Instance;
+                       return Item1.GetHashCode () ^ Item2.GetHashCode () ^ Item3.GetHashCode ();
                }
-       }
 
-       /*
-        * Hashtable whose keys are character arrays with the same length
-        */
-       class CharArrayHashtable : Hashtable {
-               sealed class ArrComparer : IComparer {
-                       private int len;
+               #region IEquatable<Tuple<T1,T2>> Members
 
-                       public ArrComparer (int len) {
-                               this.len = len;
-                       }
-
-                       public int Compare (object x, object y)
-                       {
-                               char[] a = (char[])x;
-                               char[] b = (char[])y;
-
-                               for (int i = 0; i < len; ++i)
-                                       if (a [i] != b [i])
-                                               return 1;
-                               return 0;
-                       }
+               public bool Equals (Tuple<T1, T2, T3> other)
+               {
+                       return EqualityComparer<T1>.Default.Equals (Item1, other.Item1) &&
+                               EqualityComparer<T2>.Default.Equals (Item2, other.Item2) &&
+                               EqualityComparer<T3>.Default.Equals (Item3, other.Item3);
                }
 
-               private int len;
+               #endregion
+       }
 
-               protected override int GetHash (Object key)
+       static class Tuple
+       {
+               public static Tuple<T1, T2> Create<T1, T2> (T1 item1, T2 item2)
                {
-                       char[] arr = (char[])key;
-                       int h = 0;
-
-                       for (int i = 0; i < len; ++i)
-                               h = (h << 5) - h + arr [i];
-
-                       return h;
+                       return new Tuple<T1, T2> (item1, item2);
                }
 
-               public CharArrayHashtable (int len)
+               public static Tuple<T1, T2, T3> Create<T1, T2, T3> (T1 item1, T2 item2, T3 item3)
                {
-                       this.len = len;
-                       comparer = new ArrComparer (len);
+                       return new Tuple<T1, T2, T3> (item1, item2, item3);
                }
        }
+#endif
 
-       struct Pair {
-               public object First;
-               public object Second;
-
-               public Pair (object f, object s)
+       static class ArrayComparer
+       {
+               public static bool IsEqual<T> (T[] array1, T[] array2)
                {
-                       First = f;
-                       Second = s;
-               }
-       }
+                       if (array1 == null || array2 == null)
+                               return array1 == array2;
 
-       public class Accessors {
-               public Accessor get_or_add;
-               public Accessor set_or_remove;
+                       var eq = EqualityComparer<T>.Default;
 
-               // was 'set' declared before 'get'?  was 'remove' declared before 'add'?
-               public bool declared_in_reverse;
+                       for (int i = 0; i < array1.Length; ++i) {
+                               if (!eq.Equals (array1[i], array2[i])) {
+                                       return false;
+                               }
+                       }
 
-               public Accessors (Accessor get_or_add, Accessor set_or_remove)
-               {
-                       this.get_or_add = get_or_add;
-                       this.set_or_remove = set_or_remove;
+                       return true;
                }
        }
 
        /// <summary>
-       ///   This is a wrapper around StreamReader which is seekable backwards
-       ///   within a window of around 2048 chars.
+       ///   This is an arbitrarily seekable StreamReader wrapper.
+       ///
+       ///   It uses a self-tuning buffer to cache the seekable data,
+       ///   but if the seek is too far, it may read the underly
+       ///   stream all over from the beginning.
        /// </summary>
-       public class SeekableStreamReader
+       public class SeekableStreamReader : IDisposable
        {
-               const int AverageReadLength = 1024;
-               TextReader reader;
+               public const int DefaultReadAheadSize =
+#if FULL_AST
+                       65536 / 2; // Large buffer because of ReadChars of large literal string
+#else
+                       4096 / 2;
+#endif
+
+               StreamReader reader;
                Stream stream;
-               Encoding encoding;
 
                char[] buffer;
+               int read_ahead_length;  // the length of read buffer
                int buffer_start;       // in chars
-               int char_count;         // count buffer[] valid characters
+               int char_count;         // count of filled characters in buffer[]
                int pos;                // index into buffer[]
 
-               public SeekableStreamReader (Stream stream, Encoding encoding)
+               public SeekableStreamReader (Stream stream, Encoding encoding, char[] sharedBuffer = null)
                {
                        this.stream = stream;
-                       this.encoding = encoding;
-                       
-                       this.reader = new StreamReader (stream, encoding, true);
-                       this.buffer = new char [AverageReadLength * 3];
+                       this.buffer = sharedBuffer;
+
+                       InitializeStream (DefaultReadAheadSize);
+                       reader = new StreamReader (stream, encoding, true);
+               }
 
-                       // Let the StreamWriter autodetect the encoder
-                       reader.Peek ();
+               public void Dispose ()
+               {
+                       // Needed to release stream reader buffers
+                       reader.Dispose ();
+               }
+
+               void InitializeStream (int read_length_inc)
+               {
+                       read_ahead_length += read_length_inc;
+
+                       int required_buffer_size = read_ahead_length * 2;
+
+                       if (buffer == null || buffer.Length < required_buffer_size)
+                               buffer = new char [required_buffer_size];
+
+                       stream.Position = 0;
+                       buffer_start = char_count = pos = 0;
                }
 
                /// <remarks>
@@ -455,51 +188,75 @@ namespace Mono.CSharp {
                ///   a correlation between them.
                /// </remarks>
                public int Position {
-                       get { return buffer_start + pos; }
+                       get {
+                               return buffer_start + pos;
+                       }
 
                        set {
-                               if (value > buffer_start + char_count)
-                                       throw new InternalErrorException ("can't seek that far forward: " + (pos - value));
-                               
-                               if (value < buffer_start){
-                                       // Reinitialize.
-                                       stream.Position = 0;
-                                       reader = new StreamReader (stream, encoding, true);
-                                       buffer_start = 0;
-                                       char_count = 0;
-                                       pos = 0;
-                                       Peek ();
-
-                                       while (value > buffer_start + char_count){
-                                               pos = char_count+1;
-                                               int p = Peek ();
-                                       }
-                                       pos = value - buffer_start;
+                               //
+                               // If the lookahead was too small, re-read from the beginning. Increase the buffer size while we're at it
+                               // This should never happen until we are parsing some weird source code
+                               //
+                               if (value < buffer_start) {
+                                       InitializeStream (read_ahead_length);
+
+                                       //
+                                       // Discard buffer data after underlying stream changed position
+                                       // Cannot use handy reader.DiscardBufferedData () because it for
+                                       // some strange reason resets encoding as well
+                                       //
+                                       reader = new StreamReader (stream, reader.CurrentEncoding, true);
+                               }
+
+                               while (value > buffer_start + char_count) {
+                                       pos = char_count;
+                                       if (!ReadBuffer ())
+                                               throw new InternalErrorException ("Seek beyond end of file: " + (buffer_start + char_count - value));
                                }
 
                                pos = value - buffer_start;
                        }
                }
 
-               private bool ReadBuffer ()
+               bool ReadBuffer ()
                {
                        int slack = buffer.Length - char_count;
-                       if (slack <= AverageReadLength / 2) {
-                               // shift the buffer to make room for AverageReadLength number of characters
-                               int shift = AverageReadLength - slack;
+
+                       //
+                       // read_ahead_length is only half of the buffer to deal with
+                       // reads ahead and moves back without re-reading whole buffer
+                       //
+                       if (slack <= read_ahead_length) {
+                               //
+                               // shift the buffer to make room for read_ahead_length number of characters
+                               //
+                               int shift = read_ahead_length - slack;
                                Array.Copy (buffer, shift, buffer, 0, char_count - shift);
+
+                               // Update all counters
                                pos -= shift;
                                char_count -= shift;
                                buffer_start += shift;
-                               slack += shift;         // slack == AverageReadLength
+                               slack += shift;
                        }
 
-                       int chars_read = reader.Read (buffer, char_count, slack);
-                       char_count += chars_read;
+                       char_count += reader.Read (buffer, char_count, slack);
 
                        return pos < char_count;
                }
 
+               public char[] ReadChars (int fromPosition, int toPosition)
+               {
+                       char[] chars = new char[toPosition - fromPosition];
+                       if (buffer_start <= fromPosition && toPosition <= buffer_start + buffer.Length) {
+                               Array.Copy (buffer, fromPosition - buffer_start, chars, 0, chars.Length);
+                       } else {
+                               throw new NotImplementedException ();
+                       }
+
+                       return chars;
+               }
+
                public int Peek ()
                {
                        if ((pos >= char_count) && !ReadBuffer ())
@@ -517,170 +274,52 @@ namespace Mono.CSharp {
                }
        }
 
-       public class DoubleHash {
-               const int DEFAULT_INITIAL_BUCKETS = 100;
-
-               public DoubleHash () : this (DEFAULT_INITIAL_BUCKETS) {}
-
-               public DoubleHash (int size)
-               {
-                       count = size;
-                       buckets = new Entry [size];
-               }
-
-               int count;
-               Entry [] buckets;
-               int size = 0;
-
-               class Entry {
-                       public object key1;
-                       public object key2;
-                       public int hash;
-                       public object value;
-                       public Entry next;
-
-                       public Entry (object key1, object key2, int hash, object value, Entry next)
-                       {
-                               this.key1 = key1;
-                               this.key2 = key2;
-                               this.hash = hash;
-                               this.next = next;
-                               this.value = value;
-                       }
-               }
-
-               public bool Lookup (object a, object b, out object res)
-               {
-                       int h = (a.GetHashCode () ^ b.GetHashCode ()) & 0x7FFFFFFF;
-
-                       for (Entry e = buckets [h % count]; e != null; e = e.next) {
-                               if (e.hash == h && e.key1.Equals (a) && e.key2.Equals (b)) {
-                                       res = e.value;
-                                       return true;
-                               }
-                       }
-                       res = null;
-                       return false;
-               }
-
-               public void Insert (object a, object b, object value)
+       public class UnixUtils {
+               [System.Runtime.InteropServices.DllImport ("libc", EntryPoint="isatty")]
+               extern static int _isatty (int fd);
+                       
+               public static bool isatty (int fd)
                {
-                       // Is it an existing one?
-
-                       int h = (a.GetHashCode () ^ b.GetHashCode ()) & 0x7FFFFFFF;
-
-                       for (Entry e = buckets [h % count]; e != null; e = e.next) {
-                               if (e.hash == h && e.key1.Equals (a) && e.key2.Equals (b))
-                                       e.value = value;
-                       }
-
-                       int bucket = h % count;
-                       buckets [bucket] = new Entry (a, b, h, value, buckets [bucket]);
-
-                       // Grow whenever we double in size
-                       if (size++ == count) {
-                               count <<= 1;
-                               count ++;
-
-                               Entry [] newBuckets = new Entry [count];
-                               foreach (Entry root in buckets) {
-                                       Entry e = root;
-                                       while (e != null) {
-                                               int newLoc = e.hash % count;
-                                               Entry n = e.next;
-                                               e.next = newBuckets [newLoc];
-                                               newBuckets [newLoc] = e;
-                                               e = n;
-                                       }
-                               }
-
-                               buckets = newBuckets;
+                       try {
+                               return _isatty (fd) == 1;
+                       } catch {
+                               return false;
                        }
                }
        }
 
-       class PartialMethodDefinitionInfo : MethodInfo
-       {
-               MethodOrOperator mc;
-               MethodAttributes attrs;
-
-               public PartialMethodDefinitionInfo (MethodOrOperator mc)
-               {
-                       this.mc = mc;
-                       if ((mc.ModFlags & Modifiers.STATIC) != 0)
-                               attrs = MethodAttributes.Static;
-               }
-
-               public override MethodInfo GetBaseDefinition ()
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override ICustomAttributeProvider ReturnTypeCustomAttributes
-               {
-                       get { throw new NotImplementedException (); }
-               }
-
-               public override MethodAttributes Attributes
-               {
-                       get { return attrs; }
-               }
-
-               public override MethodImplAttributes GetMethodImplementationFlags ()
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override ParameterInfo [] GetParameters ()
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override object Invoke (object obj, BindingFlags invokeAttr, Binder binder, object [] parameters, CultureInfo culture)
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override RuntimeMethodHandle MethodHandle
-               {
-                       get { throw new NotImplementedException (); }
-               }
-
-               public override Type DeclaringType
-               {
-                       get { return mc.Parent.TypeBuilder; }
-               }
-
-               public override object [] GetCustomAttributes (Type attributeType, bool inherit)
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override object [] GetCustomAttributes (bool inherit)
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override Type ReturnType {
+       /// <summary>
+       ///   An exception used to terminate the compiler resolution phase and provide completions
+       /// </summary>
+       /// <remarks>
+       ///   This is thrown when we want to return the completions or
+       ///   terminate the completion process by AST nodes used in
+       ///   the completion process.
+       /// </remarks>
+       public class CompletionResult : Exception {
+               string [] result;
+               string base_text;
+               
+               public CompletionResult (string base_text, string [] res)
+               {
+                       if (base_text == null)
+                               throw new ArgumentNullException ("base_text");
+                       this.base_text = base_text;
+
+                       result = res;
+                       Array.Sort (result);
+               }
+
+               public string [] Result {
                        get {
-                               return mc.MemberType;
+                               return result;
                        }
                }
 
-               public override bool IsDefined (Type attributeType, bool inherit)
-               {
-                       throw new NotImplementedException ();
-               }
-
-               public override string Name
-               {
-                       get { return mc.Name; }
-               }
-
-               public override Type ReflectedType
-               {
-                       get { throw new NotImplementedException (); }
+               public string BaseText {
+                       get {
+                               return base_text;
+                       }
                }
        }
-
 }