src/org/xwt/js/Interpreter.java

   1 // Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
   2 package org.xwt.js;
   3
   4 import org.xwt.util.*;
   5 import java.util.*;
   6 import java.io.*;
   7
   8 /** Encapsulates a single JS interpreter (ie call stack) */
   9 class Interpreter implements ByteCodes, Tokens {
  10
  11
  12     // Thread-Interpreter Mapping /////////////////////////////////////////////////////////////////////////
  13
  14     static Interpreter current() { return (Interpreter)threadToInterpreter.get(Thread.currentThread()); }
  15     private static Hashtable threadToInterpreter = new Hashtable();
  16
  17
  18     // Instance members and methods //////////////////////////////////////////////////////////////////////
  19
  20     int pausecount;               ///< the number of times pause() has been invoked; -1 indicates unpauseable
  21     JSFunction f = null;          ///< the currently-executing JSFunction
  22     JSScope scope;                ///< the current top-level scope (LIFO stack via NEWSCOPE/OLDSCOPE)
  23     Vec stack = new Vec();        ///< the object stack
  24     int pc = 0;                   ///< the program counter
  25
  26     Interpreter(JSFunction f, boolean pauseable, JSArray args) {
  27         stack.push(new Interpreter.CallMarker(this));    // the "root function returned" marker -- f==null
  28         this.f = f;
  29         this.pausecount = pauseable ? 0 : -1;
  30         this.scope = new JSScope(f.parentScope);
  31         stack.push(args);
  32     }
  33
  34     /** this is the only synchronization point we need in order to be threadsafe */
  35     synchronized Object resume() throws JSExn {
  36         Thread t = Thread.currentThread();
  37         Interpreter old = (Interpreter)threadToInterpreter.get(t);
  38         threadToInterpreter.put(t, this);
  39         try {
  40             return run();
  41         } finally {
  42             if (old == null) threadToInterpreter.remove(t);
  43             else threadToInterpreter.put(t, old);
  44         }
  45     }
  46
  47     static int getLine() {
  48         Interpreter c = Interpreter.current();
  49         return c == null || c.f == null || c.pc < 0 || c.pc >= c.f.size ? -1 : c.f.line[c.pc];
  50     }
  51
  52     static String getSourceName() {
  53         Interpreter c = Interpreter.current();
  54         return c == null || c.f == null ? null : c.f.sourceName;
  55     }
  56
  57     private static JSExn je(String s) { return new JSExn(getSourceName() + ":" + getLine() + " " + s); }
  58
  59     // FIXME: double check the trap logic
  60     private Object run() throws JSExn {
  61
  62         // if pausecount changes after a get/put/call, we know we've been paused
  63         final int initialPauseCount = pausecount;
  64
  65         OUTER: for(;; pc++) {
  66         try {
  67             if (f == null) return stack.pop();
  68             int op = f.op[pc];
  69             Object arg = f.arg[pc];
  70             if(op == FINALLY_DONE) {
  71                 FinallyData fd = (FinallyData) stack.pop();
  72                 if(fd == null) continue OUTER; // NOP
  73                 if(fd.exn != null) throw fd.exn;
  74                 op = fd.op;
  75                 arg = fd.arg;
  76             }
  77             switch(op) {
  78             case LITERAL: stack.push(arg); break;
  79             case OBJECT: stack.push(new JS()); break;
  80             case ARRAY: stack.push(new JSArray(JS.toNumber(arg).intValue())); break;
  81             case DECLARE: scope.declare((String)(arg==null ? stack.peek() : arg)); if(arg != null) stack.push(arg); break;
  82             case TOPSCOPE: stack.push(scope); break;
  83             case JT: if (JS.toBoolean(stack.pop())) pc += JS.toNumber(arg).intValue() - 1; break;
  84             case JF: if (!JS.toBoolean(stack.pop())) pc += JS.toNumber(arg).intValue() - 1; break;
  85             case JMP: pc += JS.toNumber(arg).intValue() - 1; break;
  86             case POP: stack.pop(); break;
  87             case SWAP: {
  88                 int depth = (arg == null ? 1 : JS.toInt(arg));
  89                 Object save = stack.elementAt(stack.size() - 1);
  90                 for(int i=stack.size() - 1; i > stack.size() - 1 - depth; i--)
  91                     stack.setElementAt(stack.elementAt(i-1), i);
  92                 stack.setElementAt(save, stack.size() - depth - 1);
  93                 break; }
  94             case DUP: stack.push(stack.peek()); break;
  95             case NEWSCOPE: scope = new JSScope(scope); break;
  96             case OLDSCOPE: scope = scope.getParentScope(); break;
  97             case ASSERT: if (!JS.toBoolean(stack.pop())) throw je("xwt.assertion.failed" /*FEATURE: line number*/); break;
  98             case BITNOT: stack.push(JS.N(~JS.toLong(stack.pop()))); break;
  99             case BANG: stack.push(JS.B(!JS.toBoolean(stack.pop()))); break;
 100             case NEWFUNCTION: stack.push(((JSFunction)arg)._cloneWithNewParentScope(scope)); break;
 101             case LABEL: break;
 102
 103             case TYPEOF: {
 104                 Object o = stack.pop();
 105                 if (o == null) stack.push(null);
 106                 else if (o instanceof JS) stack.push("object");
 107                 else if (o instanceof String) stack.push("string");
 108                 else if (o instanceof Number) stack.push("number");
 109                 else if (o instanceof Boolean) stack.push("boolean");
 110                 else throw new Error("this should not happen");
 111                 break;
 112             }
 113
 114             case PUSHKEYS: {
 115                 Object o = stack.peek();
 116                 Enumeration e = ((JS)o).keys();
 117                 JSArray a = new JSArray();
 118                 while(e.hasMoreElements()) a.addElement(e.nextElement());
 119                 stack.push(a);
 120                 break;
 121             }
 122
 123             case LOOP:
 124                 stack.push(new LoopMarker(pc, pc > 0 && f.op[pc - 1] == LABEL ? (String)f.arg[pc - 1] : (String)null, scope));
 125                 stack.push(Boolean.TRUE);
 126                 break;
 127
 128             case BREAK:
 129             case CONTINUE:
 130                 while(stack.size() > 0) {
 131                     Object o = stack.pop();
 132                     if (o instanceof CallMarker) je("break or continue not within a loop");
 133                     if (o instanceof TryMarker) {
 134                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 135                         stack.push(new FinallyData(op, arg));
 136                         scope = ((TryMarker)o).scope;
 137                         pc = ((TryMarker)o).finallyLoc - 1;
 138                         continue OUTER;
 139                     }
 140                     if (o instanceof LoopMarker) {
 141                         if (arg == null || arg.equals(((LoopMarker)o).label)) {
 142                             int loopInstructionLocation = ((LoopMarker)o).location;
 143                             int endOfLoop = ((Integer)f.arg[loopInstructionLocation]).intValue() + loopInstructionLocation;
 144                             scope = ((LoopMarker)o).scope;
 145                             if (op == CONTINUE) { stack.push(o); stack.push(Boolean.FALSE); }
 146                             pc = op == BREAK ? endOfLoop - 1 : loopInstructionLocation;
 147                             continue OUTER;
 148                         }
 149                     }
 150                 }
 151                 throw new Error("CONTINUE/BREAK invoked but couldn't find LoopMarker at " +
 152                                 getSourceName() + ":" + getLine());
 153
 154             case TRY: {
 155                 int[] jmps = (int[]) arg;
 156                 // jmps[0] is how far away the catch block is, jmps[1] is how far away the finally block is
 157                 // each can be < 0 if the specified block does not exist
 158                 stack.push(new TryMarker(jmps[0] < 0 ? -1 : pc + jmps[0], jmps[1] < 0 ? -1 : pc + jmps[1], this));
 159                 break;
 160             }
 161
 162             case RETURN: {
 163                 Object retval = stack.pop();
 164                 while(stack.size() > 0) {
 165                     Object o = stack.pop();
 166                     if (o instanceof TryMarker) {
 167                         if(((TryMarker)o).finallyLoc < 0) continue;
 168                         stack.push(retval);
 169                         stack.push(new FinallyData(RETURN));
 170                         scope = ((TryMarker)o).scope;
 171                         pc = ((TryMarker)o).finallyLoc - 1;
 172                         continue OUTER;
 173                     } else if (o instanceof CallMarker) {
 174                         if (scope instanceof Trap.TrapScope) { // handles return component of a read trap
 175                             Trap.TrapScope ts = (Trap.TrapScope)scope;
 176                             if (retval != null && retval instanceof Boolean && ((Boolean)retval).booleanValue())
 177                                 ts.cascadeHappened = true;
 178                             if (!ts.cascadeHappened) {
 179                                 ts.cascadeHappened = true;
 180                                 Trap t = ts.t.next;
 181                                 while (t != null && t.f.numFormalArgs == 0) t = t.next;
 182                                 if (t == null) {
 183                                     ((JS)ts.t.trapee).put(ts.t.name, ts.val);
 184                                     if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 185                                 } else {
 186                                     stack.push(o);
 187                                     JSArray args = new JSArray();
 188                                     args.addElement(ts.val);
 189                                     stack.push(args);
 190                                     f = t.f;
 191                                     scope = new Trap.TrapScope(f.parentScope, t, ts.val);
 192                                     pc = -1;
 193                                     continue OUTER;
 194                                 }
 195                             }
 196                         }
 197                         scope = ((CallMarker)o).scope;
 198                         pc = ((CallMarker)o).pc - 1;
 199                         f = (JSFunction)((CallMarker)o).f;
 200                         stack.push(retval);
 201                         continue OUTER;
 202                     }
 203                 }
 204                 throw new Error("error: RETURN invoked but couldn't find a CallMarker!");
 205             }
 206
 207             case PUT: {
 208                 Object val = stack.pop();
 209                 Object key = stack.pop();
 210                 Object target = stack.peek();
 211                 if (target == null)
 212                     throw je("tried to put a value to the " + key + " property on the null value");
 213                 if (!(target instanceof JS))
 214                     throw je("tried to put a value to the " + key + " property on a " + target.getClass().getName());
 215                 if (key == null)
 216                     throw je("tried to assign \"" + (val==null?"(null)":val.toString()) + "\" to the null key");
 217
 218                 Trap t = null;
 219                 if (target instanceof Trap.TrapScope && key.equals("cascade")) {
 220                     Trap.TrapScope ts = (Trap.TrapScope)target;
 221                     t = ts.t.next;
 222                     ts.cascadeHappened = true;
 223                     while (t != null && t.f.numFormalArgs == 0) t = t.next;
 224                     if (t == null) { target = ts.t.trapee; key = ts.t.name; }
 225
 226                 } else if (target instanceof Trap.TrapScope && key.equals(((Trap.TrapScope)target).t.name)) {
 227                     throw je("tried to put to " + key + " inside a trap it owns; use cascade instead");
 228
 229                 } else if (target instanceof JS) {
 230                     if (target instanceof JSScope) {
 231                         JSScope p = (JSScope)target; // search the scope-path for the trap
 232                         t = p.getTrap(key);
 233                         while (t == null && p.getParentScope() != null) { p = p.getParentScope(); t = p.getTrap(key); }
 234                     } else {
 235                         t = ((JS)target).getTrap(key);
 236                     }
 237
 238                     while (t != null && t.f.numFormalArgs == 0) t = t.next; // find the first write trap
 239                     if (t != null) {
 240                         stack.push(new CallMarker(this));
 241                         JSArray args = new JSArray();
 242                         args.addElement(val);
 243                         stack.push(args);
 244                     }
 245                 }
 246                 if (t != null) {
 247                     f = t.f;
 248                     scope = new Trap.TrapScope(f.parentScope, t, val);
 249                     pc = -1;
 250                     break;
 251                 }
 252                 ((JS)target).put(key, val);
 253                 if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 254                 stack.push(val);
 255                 break;
 256             }
 257
 258             case GET:
 259             case GET_PRESERVE: {
 260                 Object o, v;
 261                 if (op == GET) {
 262                     v = arg == null ? stack.pop() : arg;
 263                     o = stack.pop();
 264                 } else {
 265                     v = stack.pop();
 266                     o = stack.peek();
 267                     stack.push(v);
 268                 }
 269                 Object ret = null;
 270                 if (v == null) throw je("tried to get the null key from " + o);
 271                 if (o == null) throw je("tried to get property \"" + v + "\" from the null object");
 272                 if (o instanceof String || o instanceof Number || o instanceof Boolean) {
 273                     ret = getFromPrimitive(o,v);
 274                     stack.push(ret);
 275                     break;
 276                 } else if (o instanceof JS) {
 277                     Trap t = null;
 278                     if (o instanceof Trap.TrapScope && v.equals("cascade")) {
 279                         t = ((Trap.TrapScope)o).t.next;
 280                         while (t != null && t.f.numFormalArgs != 0) t = t.next;
 281                         if (t == null) { v = ((Trap.TrapScope)o).t.name; o = ((Trap.TrapScope)o).t.trapee; }
 282
 283                     } else if (o instanceof JS) {
 284                         if (o instanceof JSScope) {
 285                             JSScope p = (JSScope)o; // search the scope-path for the trap
 286                             t = p.getTrap(v);
 287                             while (t == null && p.getParentScope() != null) { p = p.getParentScope(); t = p.getTrap(v); }
 288                         } else {
 289                             t = ((JS)o).getTrap(v);
 290                         }
 291
 292                         while (t != null && t.f.numFormalArgs != 0) t = t.next; // get first read trap
 293                         if (t != null) {
 294                             stack.push(new CallMarker(this));
 295                             JSArray args = new JSArray();
 296                             stack.push(args);
 297                         }
 298                     }
 299                     if (t != null) {
 300                         f = t.f;
 301                         scope = new Trap.TrapScope(f.parentScope, t, null);
 302                         ((Trap.TrapScope)scope).cascadeHappened = true;
 303                         pc = -1;
 304                         break;
 305                     }
 306                     ret = ((JS)o).get(v);
 307                     if (ret == JS.METHOD) ret = new Stub((JS)o, v);
 308                     if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 309                     stack.push(ret);
 310                     break;
 311                 }
 312                 throw je("tried to get property " + v + " from a " + o.getClass().getName());
 313             }
 314
 315             case CALL: case CALLMETHOD: {
 316                 int numArgs = JS.toInt(arg);
 317                 Object method = null;
 318                 Object ret = null;
 319                 Object object = stack.pop();
 320
 321                 if (op == CALLMETHOD) {
 322                     if (object == JS.METHOD) {
 323                         method = stack.pop();
 324                         object = stack.pop();
 325                     } else if (object == null) {
 326                         Object name = stack.pop();
 327                         stack.pop();
 328                         throw new JSExn("function '"+name+"' not found");
 329                     } else {
 330                         stack.pop();
 331                         stack.pop();
 332                     }
 333                 }
 334                 Object[] rest = numArgs > 3 ? new Object[numArgs - 3] : null;
 335                 for(int i=numArgs - 1; i>2; i--) rest[i-3] = stack.pop();
 336                 Object a2 = numArgs <= 2 ? null : stack.pop();
 337                 Object a1 = numArgs <= 1 ? null : stack.pop();
 338                 Object a0 = numArgs <= 0 ? null : stack.pop();
 339
 340                 if (object instanceof String || object instanceof Number || object instanceof Boolean) {
 341                     ret = callMethodOnPrimitive(object, method, a0, a1, a2, null, numArgs);
 342
 343                 } else if (object instanceof JSFunction) {
 344                     // FIXME: use something similar to call0/call1/call2 here
 345                     JSArray arguments = new JSArray();
 346                     for(int i=0; i<numArgs; i++) arguments.addElement(i==0?a0:i==1?a1:i==2?a2:rest[i-3]);
 347                     stack.push(new CallMarker(this));
 348                     stack.push(arguments);
 349                     f = (JSFunction)object;
 350                     scope = new JSScope(f.parentScope);
 351                     pc = -1;
 352                     break;
 353
 354                 } else if (object instanceof JS) {
 355                     JS c = (JS)object;
 356                     ret = method == null ? c.call(a0, a1, a2, rest, numArgs) : c.callMethod(method, a0, a1, a2, rest, numArgs);
 357
 358                 } else {
 359                     throw new JSExn("can't call a " + object + " @" + pc + "\n" + f.dump());
 360
 361                 }
 362                 if (pausecount > initialPauseCount) { pc++; return null; }
 363                 stack.push(ret);
 364                 break;
 365             }
 366
 367             case THROW:
 368                 throw new JSExn(stack.pop());
 369
 370             case MAKE_GRAMMAR: {
 371                 final Grammar r = (Grammar)arg;
 372                 final JSScope final_scope = scope;
 373                 Grammar r2 = new Grammar() {
 374                         public int match(String s, int start, Hash v, JSScope scope) throws JSExn {
 375                             return r.match(s, start, v, final_scope);
 376                         }
 377                         public int matchAndWrite(String s, int start, Hash v, JSScope scope, String key) throws JSExn {
 378                             return r.matchAndWrite(s, start, v, final_scope, key);
 379                         }
 380                         public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 381                             Hash v = new Hash();
 382                             r.matchAndWrite((String)a0, 0, v, final_scope, "foo");
 383                             return v.get("foo");
 384                         }
 385                     };
 386                 Object obj = stack.pop();
 387                 if (obj != null && obj instanceof Grammar) r2 = new Grammar.Alternative((Grammar)obj, r2);
 388                 stack.push(r2);
 389                 break;
 390             }
 391
 392             case ASSIGN_SUB: case ASSIGN_ADD: {
 393                 Object val = stack.pop();
 394                 Object key = stack.pop();
 395                 Object obj = stack.peek();
 396                 if (val instanceof JSFunction && obj instanceof JS) {
 397                     // A trap addition/removal
 398                     JS js = obj instanceof JSScope ? ((JSScope)obj).top() : (JS) obj;
 399                     if(op == ASSIGN_ADD) js.addTrap(key, (JSFunction)val);
 400                     else js.delTrap(key, (JSFunction)val);
 401                     pc += ((Integer)arg).intValue() - 1;
 402                 } else {
 403                     // The following setup is VERY important. The generated bytecode depends on the stack
 404                     // being setup like this (top to bottom) KEY, OBJ, VAL, KEY, OBJ
 405                     stack.push(key);
 406                     stack.push(val);
 407                     stack.push(obj);
 408                     stack.push(key);
 409                 }
 410                 break;
 411             }
 412
 413             case ADD: {
 414                 int count = ((Number)arg).intValue();
 415                 if(count < 2) throw new Error("this should never happen");
 416                 if(count == 2) {
 417                     // common case
 418                     Object right = stack.pop();
 419                     Object left = stack.pop();
 420                     if(left instanceof String || right instanceof String)
 421                         stack.push(JS.toString(left).concat(JS.toString(right)));
 422                     else stack.push(JS.N(JS.toDouble(left) + JS.toDouble(right)));
 423                 } else {
 424                     Object[] args = new Object[count];
 425                     while(--count >= 0) args[count] = stack.pop();
 426                     if(args[0] instanceof String) {
 427                         StringBuffer sb = new StringBuffer(64);
 428                         for(int i=0;i<args.length;i++) sb.append(JS.toString(args[i]));
 429                         stack.push(sb.toString());
 430                     } else {
 431                         int numStrings = 0;
 432                         for(int i=0;i<args.length;i++) if(args[i] instanceof String) numStrings++;
 433                         if(numStrings == 0) {
 434                             double d = 0.0;
 435                             for(int i=0;i<args.length;i++) d += JS.toDouble(args[i]);
 436                             stack.push(JS.N(d));
 437                         } else {
 438                             int i=0;
 439                             StringBuffer sb = new StringBuffer(64);
 440                             if(!(args[0] instanceof String || args[1] instanceof String)) {
 441                                 double d=0.0;
 442                                 do {
 443                                     d += JS.toDouble(args[i++]);
 444                                 } while(!(args[i] instanceof String));
 445                                 sb.append(JS.toString(JS.N(d)));
 446                             }
 447                             while(i < args.length) sb.append(JS.toString(args[i++]));
 448                             stack.push(sb.toString());
 449                         }
 450                     }
 451                 }
 452                 break;
 453             }
 454
 455             default: {
 456                 Object right = stack.pop();
 457                 Object left = stack.pop();
 458                 switch(op) {
 459
 460                 case BITOR: stack.push(JS.N(JS.toLong(left) | JS.toLong(right))); break;
 461                 case BITXOR: stack.push(JS.N(JS.toLong(left) ^ JS.toLong(right))); break;
 462                 case BITAND: stack.push(JS.N(JS.toLong(left) & JS.toLong(right))); break;
 463
 464                 case SUB: stack.push(JS.N(JS.toDouble(left) - JS.toDouble(right))); break;
 465                 case MUL: stack.push(JS.N(JS.toDouble(left) * JS.toDouble(right))); break;
 466                 case DIV: stack.push(JS.N(JS.toDouble(left) / JS.toDouble(right))); break;
 467                 case MOD: stack.push(JS.N(JS.toDouble(left) % JS.toDouble(right))); break;
 468
 469                 case LSH: stack.push(JS.N(JS.toLong(left) << JS.toLong(right))); break;
 470                 case RSH: stack.push(JS.N(JS.toLong(left) >> JS.toLong(right))); break;
 471                 case URSH: stack.push(JS.N(JS.toLong(left) >>> JS.toLong(right))); break;
 472
 473                 case LT: case LE: case GT: case GE: {
 474                     if (left == null) left = JS.N(0);
 475                     if (right == null) right = JS.N(0);
 476                     int result = 0;
 477                     if (left instanceof String || right instanceof String) {
 478                         result = left.toString().compareTo(right.toString());
 479                     } else {
 480                         result = (int)java.lang.Math.ceil(JS.toDouble(left) - JS.toDouble(right));
 481                     }
 482                     stack.push(JS.B((op == LT && result < 0) || (op == LE && result <= 0) ||
 483                                (op == GT && result > 0) || (op == GE && result >= 0)));
 484                     break;
 485                 }
 486
 487                 case EQ:
 488                 case NE: {
 489                     Object l = left;
 490                     Object r = right;
 491                     boolean ret;
 492                     if (l == null) { Object tmp = r; r = l; l = tmp; }
 493                     if (l == null && r == null) ret = true;
 494                     else if (r == null) ret = false; // l != null, so its false
 495                     else if (l instanceof Boolean) ret = JS.B(JS.toBoolean(r)).equals(l);
 496                     else if (l instanceof Number) ret = JS.toNumber(r).doubleValue() == JS.toNumber(l).doubleValue();
 497                     else if (l instanceof String) ret = r != null && l.equals(r.toString());
 498                     else ret = l.equals(r);
 499                     stack.push(JS.B(op == EQ ? ret : !ret)); break;
 500                 }
 501
 502                 default: throw new Error("unknown opcode " + op);
 503                 } }
 504             }
 505
 506         } catch(JSExn e) {
 507             if(f.op[pc] != FINALLY_DONE) e.addBacktrace(f.sourceName,f.line[pc]);
 508             while(stack.size() > 0) {
 509                 Object o = stack.pop();
 510                 if (o instanceof CatchMarker || o instanceof TryMarker) {
 511                     boolean inCatch = o instanceof CatchMarker;
 512                     if(inCatch) {
 513                         o = stack.pop();
 514                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 515                     }
 516                     if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
 517                         // run the catch block, this will implicitly run the finally block, if it exists
 518                         stack.push(o);
 519                         stack.push(catchMarker);
 520                         stack.push(e.getObject());
 521                         f = ((TryMarker)o).f;
 522                         scope = ((TryMarker)o).scope;
 523                         pc = ((TryMarker)o).catchLoc - 1;
 524                         continue OUTER;
 525                     } else {
 526                         stack.push(new FinallyData(e));
 527                         f = ((TryMarker)o).f;
 528                         scope = ((TryMarker)o).scope;
 529                         pc = ((TryMarker)o).finallyLoc - 1;
 530                         continue OUTER;
 531                     }
 532                 } else if(o instanceof CallMarker) {
 533                     CallMarker cm = (CallMarker) o;
 534                     if(cm.f == null)
 535                         e.addBacktrace("<java>",0); // This might not even be worth mentioning
 536                     else
 537                         e.addBacktrace(cm.f.sourceName,cm.f.line[cm.pc-1]);
 538                 }
 539             }
 540             throw e;
 541         } // end try/catch
 542         } // end for
 543     }
 544
 545
 546
 547     // Markers //////////////////////////////////////////////////////////////////////
 548
 549     public static class CallMarker {
 550         int pc;
 551         JSScope scope;
 552         JSFunction f;
 553         public CallMarker(Interpreter cx) { pc = cx.pc + 1; scope = cx.scope; f = cx.f; }
 554     }
 555
 556     public static class CatchMarker { public CatchMarker() { } }
 557     private static CatchMarker catchMarker = new CatchMarker();
 558
 559     public static class LoopMarker {
 560         public int location;
 561         public String label;
 562         public JSScope scope;
 563         public LoopMarker(int location, String label, JSScope scope) {
 564             this.location = location;
 565             this.label = label;
 566             this.scope = scope;
 567         }
 568     }
 569     public static class TryMarker {
 570         public int catchLoc;
 571         public int finallyLoc;
 572         public JSScope scope;
 573         public JSFunction f;
 574         public TryMarker(int catchLoc, int finallyLoc, Interpreter cx) {
 575             this.catchLoc = catchLoc;
 576             this.finallyLoc = finallyLoc;
 577             this.scope = cx.scope;
 578             this.f = cx.f;
 579         }
 580     }
 581     public static class FinallyData {
 582         public int op;
 583         public Object arg;
 584         public JSExn exn;
 585         public FinallyData(int op) { this(op,null); }
 586         public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; }
 587         public FinallyData(JSExn exn) { this.exn = exn; } // Just throw this exn
 588     }
 589
 590
 591     // Operations on Primitives //////////////////////////////////////////////////////////////////////
 592
 593     static Object callMethodOnPrimitive(Object o, Object method, Object arg0, Object arg1, Object arg2, Object[] rest, int alength) throws JSExn {
 594         if (method == null || !(method instanceof String) || "".equals(method))
 595             throw new JSExn("attempt to call a non-existant method on a primitive");
 596
 597         if (o instanceof Number) {
 598             //#switch(method)
 599             case "toFixed": throw new JSExn("toFixed() not implemented");
 600             case "toExponential": throw new JSExn("toExponential() not implemented");
 601             case "toPrecision": throw new JSExn("toPrecision() not implemented");
 602             case "toString": {
 603                 int radix = alength >= 1 ? JS.toInt(arg0) : 10;
 604                 return Long.toString(((Number)o).longValue(),radix);
 605             }
 606             //#end
 607         } else if (o instanceof Boolean) {
 608             // No methods for Booleans
 609             throw new JSExn("attempt to call a method on a Boolean");
 610         }
 611
 612         String s = JS.toString(o);
 613         int slength = s.length();
 614         //#switch(method)
 615         case "substring": {
 616             int a = alength >= 1 ? JS.toInt(arg0) : 0;
 617             int b = alength >= 2 ? JS.toInt(arg1) : slength;
 618             if (a > slength) a = slength;
 619             if (b > slength) b = slength;
 620             if (a < 0) a = 0;
 621             if (b < 0) b = 0;
 622             if (a > b) { int tmp = a; a = b; b = tmp; }
 623             return s.substring(a,b);
 624         }
 625         case "substr": {
 626             int start = alength >= 1 ? JS.toInt(arg0) : 0;
 627             int len = alength >= 2 ? JS.toInt(arg1) : Integer.MAX_VALUE;
 628             if (start < 0) start = slength + start;
 629             if (start < 0) start = 0;
 630             if (len < 0) len = 0;
 631             if (len > slength - start) len = slength - start;
 632             if (len <= 0) return "";
 633             return s.substring(start,start+len);
 634         }
 635         case "charAt": {
 636             int p = alength >= 1 ? JS.toInt(arg0) : 0;
 637             if (p < 0 || p >= slength) return "";
 638             return s.substring(p,p+1);
 639         }
 640         case "charCodeAt": {
 641             int p = alength >= 1 ? JS.toInt(arg0) : 0;
 642             if (p < 0 || p >= slength) return JS.N(Double.NaN);
 643             return JS.N(s.charAt(p));
 644         }
 645         case "concat": {
 646             StringBuffer sb = new StringBuffer(slength*2).append(s);
 647             for(int i=0;i<alength;i++) sb.append(i==0?arg0:i==1?arg1:i==2?arg2:rest[i-3]);
 648             return sb.toString();
 649         }
 650         case "indexOf": {
 651             String search = alength >= 1 ? arg0.toString() : "null";
 652             int start = alength >= 2 ? JS.toInt(arg1) : 0;
 653             // Java's indexOf handles an out of bounds start index, it'll return -1
 654             return JS.N(s.indexOf(search,start));
 655         }
 656         case "lastIndexOf": {
 657             String search = alength >= 1 ? arg0.toString() : "null";
 658             int start = alength >= 2 ? JS.toInt(arg1) : 0;
 659             // Java's indexOf handles an out of bounds start index, it'll return -1
 660             return JS.N(s.lastIndexOf(search,start));
 661         }
 662         case "match": return JSRegexp.stringMatch(s,arg0);
 663         case "replace": return JSRegexp.stringReplace(s,arg0,arg1);
 664         case "search": return JSRegexp.stringSearch(s,arg0);
 665         case "split": return JSRegexp.stringSplit(s,arg0,arg1,alength);
 666         case "toLowerCase": return s.toLowerCase();
 667         case "toUpperCase": return s.toUpperCase();
 668         case "toString": return s;
 669         case "slice": {
 670             int a = alength >= 1 ? JS.toInt(arg0) : 0;
 671             int b = alength >= 2 ? JS.toInt(arg1) : slength;
 672             if (a < 0) a = slength + a;
 673             if (b < 0) b = slength + b;
 674             if (a < 0) a = 0;
 675             if (b < 0) b = 0;
 676             if (a > slength) a = slength;
 677             if (b > slength) b = slength;
 678             if (a > b) return "";
 679             return s.substring(a,b);
 680         }
 681         //#end
 682         throw new JSExn("Attempted to call non-existent method: " + method);
 683     }
 684
 685     static Object getFromPrimitive(Object o, Object key) throws JSExn {
 686         boolean returnJS = false;
 687         if (o instanceof Boolean) {
 688             throw new JSExn("cannot call methods on Booleans");
 689         } else if (o instanceof Number) {
 690             if (key.equals("toPrecision") || key.equals("toExponential") || key.equals("toFixed"))
 691                 returnJS = true;
 692         }
 693         if (!returnJS) {
 694             // the string stuff applies to everything
 695             String s = o.toString();
 696
 697             // this is sort of ugly, but this list should never change
 698             // These should provide a complete (enough) implementation of the ECMA-262 String object
 699
 700             //#switch(key)
 701             case "length": return JS.N(s.length());
 702             case "substring": returnJS = true; break;
 703             case "charAt": returnJS = true; break;
 704             case "charCodeAt": returnJS = true; break;
 705             case "concat": returnJS = true; break;
 706             case "indexOf": returnJS = true; break;
 707             case "lastIndexOf": returnJS = true; break;
 708             case "match": returnJS = true; break;
 709             case "replace": returnJS = true; break;
 710             case "seatch": returnJS = true; break;
 711             case "slice": returnJS = true; break;
 712             case "split": returnJS = true; break;
 713             case "toLowerCase": returnJS = true; break;
 714             case "toUpperCase": returnJS = true; break;
 715             case "toString": returnJS = true; break;
 716             case "substr": returnJS = true; break;
 717            //#end
 718         }
 719         if (returnJS) {
 720             final Object target = o;
 721             final String method = key.toString();
 722             return new JS() {
 723                     public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 724                         if (nargs > 2) throw new JSExn("cannot call that method with that many arguments");
 725                         return callMethodOnPrimitive(target, method, a0, a1, a2, rest, nargs);
 726                     }
 727             };
 728         }
 729         return null;
 730     }
 731
 732     private static class Stub extends JS {
 733         private Object method;
 734         JS obj;
 735         public Stub(JS obj, Object method) { this.obj = obj; this.method = method; }
 736         public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 737             return ((JS)obj).callMethod(method, a0, a1, a2, rest, nargs);
 738         }
 739     }
 740 }