mcs/mcs/support.cs

   1 //
   2 // support.cs: Support routines to work around the fact that System.Reflection.Emit
   3 // can not introspect types that are being constructed
   4 //
   5 // Author:
   6 //   Miguel de Icaza (miguel@ximian.com)
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10
  11 using System;
  12 using System.IO;
  13 using System.Text;
  14 using System.Reflection;
  15 using System.Collections;
  16 using System.Reflection.Emit;
  17 using System.Globalization;
  18
  19 namespace Mono.CSharp {
  20
  21         public interface ParameterData {
  22                 Type ParameterType (int pos);
  23                 Type [] Types { get; }
  24                 int  Count { get; }
  25                 bool HasParams { get; }
  26                 string ParameterName (int pos);
  27                 string ParameterDesc (int pos);
  28                 Parameter.Modifier ParameterModifier (int pos);
  29                 string GetSignatureForError ();
  30         }
  31
  32         public class ReflectionParameters : ParameterData {
  33                 ParameterInfo [] pi;
  34                 Type [] types;
  35                 int params_idx = -1;
  36                 bool is_varargs;
  37                 ParameterData gpd;
  38
  39                 public ReflectionParameters (MethodBase mb)
  40                 {
  41                         ParameterInfo [] pi = mb.GetParameters ();
  42                         is_varargs = (mb.CallingConvention & CallingConventions.VarArgs) != 0;
  43
  44                         this.pi = pi;
  45                         int count = pi.Length;
  46
  47                         if (count == 0) {
  48                                 types = Type.EmptyTypes;
  49                                 return;
  50                         }
  51
  52                         types = new Type [count];
  53                         for (int i = 0; i < count; i++)
  54                                 types [i] = pi [i].ParameterType;
  55
  56                         // TODO: This (if) should be done one level higher to correctly use
  57                         // out caching facilities.
  58                         MethodBase generic = TypeManager.DropGenericMethodArguments (mb);
  59                         if (generic != mb) {
  60                                 gpd = TypeManager.GetParameterData (generic);
  61                                 if (gpd.HasParams) {
  62                                         for (int i = gpd.Count; i != 0; --i) {
  63                                                 if ((gpd.ParameterModifier (i-1) & Parameter.Modifier.PARAMS) != 0) {
  64                                                         this.params_idx = i-1;
  65                                                         break;
  66                                                 }
  67                                         }
  68                                 }
  69                                 return;
  70                         }
  71
  72                         //
  73                         // So far, the params attribute can be used in C# for the last
  74                         // and next to last method parameters.
  75                         // If some other language can place it anywhere we will
  76                         // have to analyze all parameters and not just last 2.
  77                         //
  78                         --count;
  79                         for (int i = count; i >= 0 && i > count - 2; --i) {
  80                                 if (!pi [i].ParameterType.IsArray)
  81                                         continue;
  82
  83                                 object [] attrs = pi [i].GetCustomAttributes (TypeManager.param_array_type, true);
  84                                 if (attrs.Length == 1) {
  85                                         params_idx = i;
  86                                         return;
  87                                 }
  88                         }
  89                 }
  90
  91                 public override bool Equals (object obj)
  92                 {
  93                         ReflectionParameters rp = obj as ReflectionParameters;
  94                         if (rp == null)
  95                                 return false;
  96
  97                         if (Count != rp.Count)
  98                                 return false;
  99
 100                         for (int i = 0; i < Count; ++i) {
 101                         if (!types [i].Equals (rp.types [i]))
 102                                 return false;
 103                         }
 104                         return true;
 105                 }
 106
 107                 public override int GetHashCode ()
 108                 {
 109                         return base.GetHashCode ();
 110                 }
 111
 112                 public string GetSignatureForError ()
 113                 {
 114                         StringBuilder sb = new StringBuilder ("(");
 115                         for (int i = 0; i < pi.Length; ++i) {
 116                                 if (i != 0)
 117                                         sb.Append (", ");
 118                                 sb.Append (ParameterDesc (i));
 119                         }
 120                         if (is_varargs) {
 121                                 if (pi.Length > 0)
 122                                         sb.Append (", ");
 123                                 sb.Append ("__arglist");
 124                         }
 125                         sb.Append (')');
 126                         return sb.ToString ();
 127                 }
 128
 129                 public Type ParameterType (int pos)
 130                 {
 131                         if (is_varargs && pos >= pi.Length)
 132                                 return TypeManager.runtime_argument_handle_type;
 133
 134                         return pi [pos].ParameterType;
 135                 }
 136
 137                 public string ParameterName (int pos)
 138                 {
 139                         if (gpd != null)
 140                                 return gpd.ParameterName (pos);
 141
 142                         if (is_varargs && pos >= pi.Length)
 143                                 return "__arglist";
 144
 145                         return pi [pos].Name;
 146                 }
 147
 148                 public string ParameterDesc (int pos)
 149                 {
 150                         if (is_varargs && pos >= pi.Length)
 151                                 return "";
 152
 153                         StringBuilder sb = new StringBuilder ();
 154
 155                         if (pi [pos].IsIn)
 156                                 sb.Append ("in ");
 157
 158                         Type partype = ParameterType (pos);
 159                         if (partype.IsByRef){
 160                                 partype = TypeManager.GetElementType (partype);
 161                                 if (pi [pos].IsOut)
 162                                         sb.Append ("out ");
 163                                 else
 164                                         sb.Append ("ref ");
 165                         }
 166
 167                         if (params_idx == pos)
 168                                 sb.Append ("params ");
 169
 170                         sb.Append (TypeManager.CSharpName (partype).Replace ("&", ""));
 171
 172                         return sb.ToString ();
 173                 }
 174
 175                 public Parameter.Modifier ParameterModifier (int pos)
 176                 {
 177                         if (pos == params_idx)
 178                                 return Parameter.Modifier.PARAMS;
 179                         else if (is_varargs && pos >= pi.Length)
 180                                 return Parameter.Modifier.ARGLIST;
 181
 182                         if (gpd != null)
 183                                 return gpd.ParameterModifier (pos);
 184
 185                         Type t = pi [pos].ParameterType;
 186                         if (t.IsByRef){
 187                                 if ((pi [pos].Attributes & (ParameterAttributes.Out|ParameterAttributes.In)) == ParameterAttributes.Out)
 188                                         return Parameter.Modifier.OUT;
 189                                 else
 190                                         return Parameter.Modifier.REF;
 191                         }
 192
 193                         return Parameter.Modifier.NONE;
 194                 }
 195
 196                 public int Count {
 197                         get { return is_varargs ? pi.Length + 1 : pi.Length; }
 198                 }
 199
 200                 public bool HasParams {
 201                         get { return params_idx != -1; }
 202                 }
 203
 204                 public Type[] Types {
 205                         get { return types; }
 206                 }
 207         }
 208
 209 #if GMCS_SOURCE
 210         public class ReflectionConstraints : GenericConstraints
 211         {
 212                 GenericParameterAttributes attrs;
 213                 Type base_type;
 214                 Type class_constraint;
 215                 Type[] iface_constraints;
 216                 string name;
 217
 218                 public static GenericConstraints GetConstraints (Type t)
 219                 {
 220                         Type [] constraints = t.GetGenericParameterConstraints ();
 221                         GenericParameterAttributes attrs = t.GenericParameterAttributes;
 222                         if (constraints.Length == 0 && attrs == GenericParameterAttributes.None)
 223                                 return null;
 224                         return new ReflectionConstraints (t.Name, constraints, attrs);
 225                 }
 226
 227                 private ReflectionConstraints (string name, Type [] constraints, GenericParameterAttributes attrs)
 228                 {
 229                         this.name = name;
 230                         this.attrs = attrs;
 231
 232                         if ((constraints.Length > 0) && !constraints [0].IsInterface) {
 233                                 class_constraint = constraints [0];
 234                                 iface_constraints = new Type [constraints.Length - 1];
 235                                 Array.Copy (constraints, 1, iface_constraints, 0, constraints.Length - 1);
 236                         } else
 237                                 iface_constraints = constraints;
 238
 239                         if (HasValueTypeConstraint)
 240                                 base_type = TypeManager.value_type;
 241                         else if (class_constraint != null)
 242                                 base_type = class_constraint;
 243                         else
 244                                 base_type = TypeManager.object_type;
 245                 }
 246
 247                 public override string TypeParameter {
 248                         get { return name; }
 249                 }
 250
 251                 public override GenericParameterAttributes Attributes {
 252                         get { return attrs; }
 253                 }
 254
 255                 public override Type ClassConstraint {
 256                         get { return class_constraint; }
 257                 }
 258
 259                 public override Type EffectiveBaseClass {
 260                         get { return base_type; }
 261                 }
 262
 263                 public override Type[] InterfaceConstraints {
 264                         get { return iface_constraints; }
 265                 }
 266         }
 267 #endif
 268
 269         class PtrHashtable : Hashtable {
 270                 sealed class PtrComparer : IComparer {
 271                         private PtrComparer () {}
 272
 273                         public static PtrComparer Instance = new PtrComparer ();
 274
 275                         public int Compare (object x, object y)
 276                         {
 277                                 if (x == y)
 278                                         return 0;
 279                                 else
 280                                         return 1;
 281                         }
 282                 }
 283
 284                 public PtrHashtable ()
 285                 {
 286                         comparer = PtrComparer.Instance;
 287                 }
 288         }
 289
 290         /*
 291          * Hashtable whose keys are character arrays with the same length
 292          */
 293         class CharArrayHashtable : Hashtable {
 294                 sealed class ArrComparer : IComparer {
 295                         private int len;
 296
 297                         public ArrComparer (int len) {
 298                                 this.len = len;
 299                         }
 300
 301                         public int Compare (object x, object y)
 302                         {
 303                                 char[] a = (char[])x;
 304                                 char[] b = (char[])y;
 305
 306                                 for (int i = 0; i < len; ++i)
 307                                         if (a [i] != b [i])
 308                                                 return 1;
 309                                 return 0;
 310                         }
 311                 }
 312
 313                 private int len;
 314
 315                 protected override int GetHash (Object key)
 316                 {
 317                         char[] arr = (char[])key;
 318                         int h = 0;
 319
 320                         for (int i = 0; i < len; ++i)
 321                                 h = (h << 5) - h + arr [i];
 322
 323                         return h;
 324                 }
 325
 326                 public CharArrayHashtable (int len)
 327                 {
 328                         this.len = len;
 329                         comparer = new ArrComparer (len);
 330                 }
 331         }
 332
 333         struct Pair {
 334                 public object First;
 335                 public object Second;
 336
 337                 public Pair (object f, object s)
 338                 {
 339                         First = f;
 340                         Second = s;
 341                 }
 342         }
 343
 344         /// <summary>
 345         ///   This is a wrapper around StreamReader which is seekable backwards
 346         ///   within a window of around 2048 chars.
 347         /// </summary>
 348         public class SeekableStreamReader
 349         {
 350                 public SeekableStreamReader (StreamReader reader)
 351                 {
 352                         this.reader = reader;
 353                         this.buffer = new char [AverageReadLength * 3];
 354
 355                         // Let the StreamWriter autodetect the encoder
 356                         reader.Peek ();
 357                 }
 358
 359                 public SeekableStreamReader (Stream stream, Encoding encoding)
 360                         : this (new StreamReader (stream, encoding, true))
 361                 { }
 362
 363                 StreamReader reader;
 364
 365                 private const int AverageReadLength = 1024;
 366
 367                 char[] buffer;
 368                 int buffer_start;       // in chars
 369                 int char_count;         // count buffer[] valid characters
 370                 int pos;                // index into buffer[]
 371
 372                 /// <remarks>
 373                 ///   This value corresponds to the current position in a stream of characters.
 374                 ///   The StreamReader hides its manipulation of the underlying byte stream and all
 375                 ///   character set/decoding issues.  Thus, we cannot use this position to guess at
 376                 ///   the corresponding position in the underlying byte stream even though there is
 377                 ///   a correlation between them.
 378                 /// </remarks>
 379                 public int Position {
 380                         get { return buffer_start + pos; }
 381
 382                         set {
 383                                 if (value < buffer_start || value > buffer_start + char_count)
 384                                         throw new InternalErrorException ("can't seek that far back: " + (pos - value));
 385                                 pos = value - buffer_start;
 386                         }
 387                 }
 388
 389                 private bool ReadBuffer ()
 390                 {
 391                         int slack = buffer.Length - char_count;
 392                         if (slack <= AverageReadLength / 2) {
 393                                 // shift the buffer to make room for AverageReadLength number of characters
 394                                 int shift = AverageReadLength - slack;
 395                                 Array.Copy (buffer, shift, buffer, 0, char_count - shift);
 396                                 pos -= shift;
 397                                 char_count -= shift;
 398                                 buffer_start += shift;
 399                                 slack += shift;         // slack == AverageReadLength
 400                         }
 401
 402                         int chars_read = reader.Read (buffer, char_count, slack);
 403                         char_count += chars_read;
 404
 405                         return pos < char_count;
 406                 }
 407
 408                 public int Peek ()
 409                 {
 410                         if ((pos >= char_count) && !ReadBuffer ())
 411                                 return -1;
 412
 413                         return buffer [pos];
 414                 }
 415
 416                 public int Read ()
 417                 {
 418                         if ((pos >= char_count) && !ReadBuffer ())
 419                                 return -1;
 420
 421                         return buffer [pos++];
 422                 }
 423         }
 424
 425         public class DoubleHash {
 426                 const int DEFAULT_INITIAL_BUCKETS = 100;
 427
 428                 public DoubleHash () : this (DEFAULT_INITIAL_BUCKETS) {}
 429
 430                 public DoubleHash (int size)
 431                 {
 432                         count = size;
 433                         buckets = new Entry [size];
 434                 }
 435
 436                 int count;
 437                 Entry [] buckets;
 438                 int size = 0;
 439
 440                 class Entry {
 441                         public object key1;
 442                         public object key2;
 443                         public int hash;
 444                         public object value;
 445                         public Entry next;
 446
 447                         public Entry (object key1, object key2, int hash, object value, Entry next)
 448                         {
 449                                 this.key1 = key1;
 450                                 this.key2 = key2;
 451                                 this.hash = hash;
 452                                 this.next = next;
 453                                 this.value = value;
 454                         }
 455                 }
 456
 457                 public bool Lookup (object a, object b, out object res)
 458                 {
 459                         int h = (a.GetHashCode () ^ b.GetHashCode ()) & 0x7FFFFFFF;
 460
 461                         for (Entry e = buckets [h % count]; e != null; e = e.next) {
 462                                 if (e.hash == h && e.key1.Equals (a) && e.key2.Equals (b)) {
 463                                         res = e.value;
 464                                         return true;
 465                                 }
 466                         }
 467                         res = null;
 468                         return false;
 469                 }
 470
 471                 public void Insert (object a, object b, object value)
 472                 {
 473                         // Is it an existing one?
 474
 475                         int h = (a.GetHashCode () ^ b.GetHashCode ()) & 0x7FFFFFFF;
 476
 477                         for (Entry e = buckets [h % count]; e != null; e = e.next) {
 478                                 if (e.hash == h && e.key1.Equals (a) && e.key2.Equals (b))
 479                                         e.value = value;
 480                         }
 481
 482                         int bucket = h % count;
 483                         buckets [bucket] = new Entry (a, b, h, value, buckets [bucket]);
 484
 485                         // Grow whenever we double in size
 486                         if (size++ == count) {
 487                                 count <<= 1;
 488                                 count ++;
 489
 490                                 Entry [] newBuckets = new Entry [count];
 491                                 foreach (Entry root in buckets) {
 492                                         Entry e = root;
 493                                         while (e != null) {
 494                                                 int newLoc = e.hash % count;
 495                                                 Entry n = e.next;
 496                                                 e.next = newBuckets [newLoc];
 497                                                 newBuckets [newLoc] = e;
 498                                                 e = n;
 499                                         }
 500                                 }
 501
 502                                 buckets = newBuckets;
 503                         }
 504                 }
 505         }
 506 }