src/org/ibex/js/Interpreter.java

   1 // Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
   2 package org.ibex.js;
   3
   4 import org.ibex.util.*;
   5 import java.util.*;
   6
   7 /** Encapsulates a single JS interpreter (ie call stack) */
   8 class Interpreter implements ByteCodes, Tokens {
   9     private static final int MAX_STACK_SIZE = 512;
  10
  11     // Thread-Interpreter Mapping /////////////////////////////////////////////////////////////////////////
  12
  13     static Interpreter current() { return (Interpreter)threadToInterpreter.get(Thread.currentThread()); }
  14     private static Hashtable threadToInterpreter = new Hashtable();
  15
  16
  17     // Instance members and methods //////////////////////////////////////////////////////////////////////
  18
  19     int pausecount;               ///< the number of times pause() has been invoked; -1 indicates unpauseable
  20     JSFunction f = null;          ///< the currently-executing JSFunction
  21     JSScope scope;                ///< the current top-level scope (LIFO stack via NEWSCOPE/OLDSCOPE)
  22     Vec stack = new Vec();        ///< the object stack
  23     int pc = 0;                   ///< the program counter
  24
  25     Interpreter(JSFunction f, boolean pauseable, JSArray args) {
  26         stack.push(new Interpreter.CallMarker(this));    // the "root function returned" marker -- f==null
  27         this.f = f;
  28         this.pausecount = pauseable ? 0 : -1;
  29         this.scope = new JSScope(f.parentScope);
  30         stack.push(args);
  31     }
  32
  33     /** this is the only synchronization point we need in order to be threadsafe */
  34     synchronized Object resume() throws JSExn {
  35         Thread t = Thread.currentThread();
  36         Interpreter old = (Interpreter)threadToInterpreter.get(t);
  37         threadToInterpreter.put(t, this);
  38         try {
  39             return run();
  40         } finally {
  41             if (old == null) threadToInterpreter.remove(t);
  42             else threadToInterpreter.put(t, old);
  43         }
  44     }
  45
  46     static int getLine() {
  47         Interpreter c = Interpreter.current();
  48         return c == null || c.f == null || c.pc < 0 || c.pc >= c.f.size ? -1 : c.f.line[c.pc];
  49     }
  50
  51     static String getSourceName() {
  52         Interpreter c = Interpreter.current();
  53         return c == null || c.f == null ? null : c.f.sourceName;
  54     }
  55
  56     private static JSExn je(String s) { return new JSExn(getSourceName() + ":" + getLine() + " " + s); }
  57
  58     // FIXME: double check the trap logic
  59     private Object run() throws JSExn {
  60
  61         // if pausecount changes after a get/put/call, we know we've been paused
  62         final int initialPauseCount = pausecount;
  63
  64         OUTER: for(;; pc++) {
  65         try {
  66             if (f == null) return stack.pop();
  67             int op = f.op[pc];
  68             Object arg = f.arg[pc];
  69             if(op == FINALLY_DONE) {
  70                 FinallyData fd = (FinallyData) stack.pop();
  71                 if(fd == null) continue OUTER; // NOP
  72                 if(fd.exn != null) throw fd.exn;
  73                 op = fd.op;
  74                 arg = fd.arg;
  75             }
  76             switch(op) {
  77             case LITERAL: stack.push(arg); break;
  78             case OBJECT: stack.push(new JS()); break;
  79             case ARRAY: stack.push(new JSArray(JS.toNumber(arg).intValue())); break;
  80             case DECLARE: scope.declare((String)(arg==null ? stack.peek() : arg)); if(arg != null) stack.push(arg); break;
  81             case TOPSCOPE: stack.push(scope); break;
  82             case JT: if (JS.toBoolean(stack.pop())) pc += JS.toNumber(arg).intValue() - 1; break;
  83             case JF: if (!JS.toBoolean(stack.pop())) pc += JS.toNumber(arg).intValue() - 1; break;
  84             case JMP: pc += JS.toNumber(arg).intValue() - 1; break;
  85             case POP: stack.pop(); break;
  86             case SWAP: {
  87                 int depth = (arg == null ? 1 : JS.toInt(arg));
  88                 Object save = stack.elementAt(stack.size() - 1);
  89                 for(int i=stack.size() - 1; i > stack.size() - 1 - depth; i--)
  90                     stack.setElementAt(stack.elementAt(i-1), i);
  91                 stack.setElementAt(save, stack.size() - depth - 1);
  92                 break; }
  93             case DUP: stack.push(stack.peek()); break;
  94             case NEWSCOPE: scope = new JSScope(scope); break;
  95             case OLDSCOPE: scope = scope.getParentScope(); break;
  96             case ASSERT:
  97                 if (JS.checkAssertions && !JS.toBoolean(stack.pop()))
  98                     throw je("ibex.assertion.failed" /*FEATURE: line number*/); break;
  99             case BITNOT: stack.push(JS.N(~JS.toLong(stack.pop()))); break;
 100             case BANG: stack.push(JS.B(!JS.toBoolean(stack.pop()))); break;
 101             case NEWFUNCTION: stack.push(((JSFunction)arg)._cloneWithNewParentScope(scope)); break;
 102             case LABEL: break;
 103
 104             case TYPEOF: {
 105                 Object o = stack.pop();
 106                 if (o == null) stack.push(null);
 107                 else if (o instanceof JS) stack.push("object");
 108                 else if (o instanceof String) stack.push("string");
 109                 else if (o instanceof Number) stack.push("number");
 110                 else if (o instanceof Boolean) stack.push("boolean");
 111                 else throw new Error("this should not happen");
 112                 break;
 113             }
 114
 115             case PUSHKEYS: {
 116                 Object o = stack.peek();
 117                 Enumeration e = ((JS)o).keys();
 118                 JSArray a = new JSArray();
 119                 while(e.hasMoreElements()) a.addElement(e.nextElement());
 120                 stack.push(a);
 121                 break;
 122             }
 123
 124             case LOOP:
 125                 stack.push(new LoopMarker(pc, pc > 0 && f.op[pc - 1] == LABEL ? (String)f.arg[pc - 1] : (String)null, scope));
 126                 stack.push(Boolean.TRUE);
 127                 break;
 128
 129             case BREAK:
 130             case CONTINUE:
 131                 while(stack.size() > 0) {
 132                     Object o = stack.pop();
 133                     if (o instanceof CallMarker) je("break or continue not within a loop");
 134                     if (o instanceof TryMarker) {
 135                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 136                         stack.push(new FinallyData(op, arg));
 137                         scope = ((TryMarker)o).scope;
 138                         pc = ((TryMarker)o).finallyLoc - 1;
 139                         continue OUTER;
 140                     }
 141                     if (o instanceof LoopMarker) {
 142                         if (arg == null || arg.equals(((LoopMarker)o).label)) {
 143                             int loopInstructionLocation = ((LoopMarker)o).location;
 144                             int endOfLoop = ((Integer)f.arg[loopInstructionLocation]).intValue() + loopInstructionLocation;
 145                             scope = ((LoopMarker)o).scope;
 146                             if (op == CONTINUE) { stack.push(o); stack.push(Boolean.FALSE); }
 147                             pc = op == BREAK ? endOfLoop - 1 : loopInstructionLocation;
 148                             continue OUTER;
 149                         }
 150                     }
 151                 }
 152                 throw new Error("CONTINUE/BREAK invoked but couldn't find LoopMarker at " +
 153                                 getSourceName() + ":" + getLine());
 154
 155             case TRY: {
 156                 int[] jmps = (int[]) arg;
 157                 // jmps[0] is how far away the catch block is, jmps[1] is how far away the finally block is
 158                 // each can be < 0 if the specified block does not exist
 159                 stack.push(new TryMarker(jmps[0] < 0 ? -1 : pc + jmps[0], jmps[1] < 0 ? -1 : pc + jmps[1], this));
 160                 break;
 161             }
 162
 163             case RETURN: {
 164                 Object retval = stack.pop();
 165                 while(stack.size() > 0) {
 166                     Object o = stack.pop();
 167                     if (o instanceof TryMarker) {
 168                         if(((TryMarker)o).finallyLoc < 0) continue;
 169                         stack.push(retval);
 170                         stack.push(new FinallyData(RETURN));
 171                         scope = ((TryMarker)o).scope;
 172                         pc = ((TryMarker)o).finallyLoc - 1;
 173                         continue OUTER;
 174                     } else if (o instanceof CallMarker) {
 175                         if (scope instanceof Trap.TrapScope) { // handles return component of a read trap
 176                             Trap.TrapScope ts = (Trap.TrapScope)scope;
 177                             if (retval != null && retval instanceof Boolean && ((Boolean)retval).booleanValue())
 178                                 ts.cascadeHappened = true;
 179                             if (!ts.cascadeHappened) {
 180                                 ts.cascadeHappened = true;
 181                                 Trap t = ts.t.next;
 182                                 while (t != null && t.f.numFormalArgs == 0) t = t.next;
 183                                 if (t == null) {
 184                                     ((JS)ts.t.trapee).put(ts.t.name, ts.val);
 185                                     if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 186                                 } else {
 187                                     stack.push(o);
 188                                     JSArray args = new JSArray();
 189                                     args.addElement(ts.val);
 190                                     stack.push(args);
 191                                     f = t.f;
 192                                     scope = new Trap.TrapScope(f.parentScope, t, ts.val);
 193                                     pc = -1;
 194                                     continue OUTER;
 195                                 }
 196                             }
 197                         }
 198                         scope = ((CallMarker)o).scope;
 199                         pc = ((CallMarker)o).pc - 1;
 200                         f = (JSFunction)((CallMarker)o).f;
 201                         stack.push(retval);
 202                         continue OUTER;
 203                     }
 204                 }
 205                 throw new Error("error: RETURN invoked but couldn't find a CallMarker!");
 206             }
 207
 208             case PUT: {
 209                 Object val = stack.pop();
 210                 Object key = stack.pop();
 211                 Object target = stack.peek();
 212                 if (target == null)
 213                     throw je("tried to put a value to the " + key + " property on the null value");
 214                 if (!(target instanceof JS))
 215                     throw je("tried to put a value to the " + key + " property on a " + target.getClass().getName());
 216                 if (key == null)
 217                     throw je("tried to assign \"" + (val==null?"(null)":val.toString()) + "\" to the null key");
 218
 219                 Trap t = null;
 220                 if (target instanceof JSScope && key.equals("cascade")) {
 221                     Trap.TrapScope ts = null;
 222                     JSScope p = (JSScope)target; // search the scope-path for the trap
 223                     if (target instanceof Trap.TrapScope) {
 224                         ts = (Trap.TrapScope)target;
 225                     } else {
 226                         while (ts == null && p.getParentScope() != null) {
 227                             p = p.getParentScope();
 228                             if (p instanceof Trap.TrapScope) ts = (Trap.TrapScope)p;
 229                         }
 230                     }
 231                     if(ts != null) {
 232                         t = ts.t.next;
 233                         ts.cascadeHappened = true;
 234                         while (t != null && t.f.numFormalArgs == 0) t = t.next;
 235                         if (t == null) { target = ts.t.trapee; key = ts.t.name; }
 236                     }
 237                 }
 238                 if(t == null) {
 239                     if (target instanceof JSScope) {
 240                         JSScope p = (JSScope)target; // search the scope-path for the trap
 241                         t = p.getTrap(key);
 242                         while (t == null && p.getParentScope() != null) { p = p.getParentScope(); t = p.getTrap(key); }
 243                     } else {
 244                         t = ((JS)target).getTrap(key);
 245                     }
 246                     while (t != null && t.f.numFormalArgs == 0) t = t.next; // find the first write trap
 247                 }
 248                 if (t != null) {
 249                     stack.push(new CallMarker(this));
 250                     if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
 251                     JSArray args = new JSArray();
 252                     args.addElement(val);
 253                     stack.push(args);
 254                     f = t.f;
 255                     scope = new Trap.TrapScope(f.parentScope, t, val);
 256                     pc = -1;
 257                     break;
 258                 }
 259                 ((JS)target).put(key, val);
 260                 if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 261                 stack.push(val);
 262                 break;
 263             }
 264
 265             case GET:
 266             case GET_PRESERVE: {
 267                 Object o, v;
 268                 if (op == GET) {
 269                     v = arg == null ? stack.pop() : arg;
 270                     o = stack.pop();
 271                 } else {
 272                     v = stack.pop();
 273                     o = stack.peek();
 274                     stack.push(v);
 275                 }
 276                 Object ret = null;
 277                 if (v == null) throw je("tried to get the null key from " + o);
 278                 if (o == null) throw je("tried to get property \"" + v + "\" from the null object");
 279                 if (o instanceof String || o instanceof Number || o instanceof Boolean) {
 280                     ret = getFromPrimitive(o,v);
 281                     stack.push(ret);
 282                     break;
 283                 } else if (o instanceof JS) {
 284                     Trap t = null;
 285                     if (o instanceof Trap.TrapScope && v.equals("cascade")) {
 286                         t = ((Trap.TrapScope)o).t.next;
 287                         while (t != null && t.f.numFormalArgs != 0) t = t.next;
 288                         if (t == null) { v = ((Trap.TrapScope)o).t.name; o = ((Trap.TrapScope)o).t.trapee; }
 289
 290                     } else if (o instanceof JS) {
 291                         if (o instanceof JSScope) {
 292                             JSScope p = (JSScope)o; // search the scope-path for the trap
 293                             t = p.getTrap(v);
 294                             while (t == null && p.getParentScope() != null) { p = p.getParentScope(); t = p.getTrap(v); }
 295                         } else {
 296                             t = ((JS)o).getTrap(v);
 297                         }
 298                         while (t != null && t.f.numFormalArgs != 0) t = t.next; // get first read trap
 299                     }
 300                     if (t != null) {
 301                         stack.push(new CallMarker(this));
 302                         if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
 303                         JSArray args = new JSArray();
 304                         stack.push(args);
 305                         f = t.f;
 306                         scope = new Trap.TrapScope(f.parentScope, t, null);
 307                         ((Trap.TrapScope)scope).cascadeHappened = true;
 308                         pc = -1;
 309                         break;
 310                     }
 311                     ret = ((JS)o).get(v);
 312                     if (ret == JS.METHOD) ret = new Stub((JS)o, v);
 313                     if (pausecount > initialPauseCount) { pc++; return null; }   // we were paused
 314                     stack.push(ret);
 315                     break;
 316                 }
 317                 throw je("tried to get property " + v + " from a " + o.getClass().getName());
 318             }
 319
 320             case CALL: case CALLMETHOD: {
 321                 int numArgs = JS.toInt(arg);
 322                 Object method = null;
 323                 Object ret = null;
 324                 Object object = stack.pop();
 325
 326                 if (op == CALLMETHOD) {
 327                     if (object == JS.METHOD) {
 328                         method = stack.pop();
 329                         object = stack.pop();
 330                     } else if (object == null) {
 331                         Object name = stack.pop();
 332                         stack.pop();
 333                         throw new JSExn("function '"+name+"' not found");
 334                     } else {
 335                         stack.pop();
 336                         stack.pop();
 337                     }
 338                 }
 339                 Object[] rest = numArgs > 3 ? new Object[numArgs - 3] : null;
 340                 for(int i=numArgs - 1; i>2; i--) rest[i-3] = stack.pop();
 341                 Object a2 = numArgs <= 2 ? null : stack.pop();
 342                 Object a1 = numArgs <= 1 ? null : stack.pop();
 343                 Object a0 = numArgs <= 0 ? null : stack.pop();
 344
 345                 if (object instanceof String || object instanceof Number || object instanceof Boolean) {
 346                     ret = callMethodOnPrimitive(object, method, a0, a1, a2, null, numArgs);
 347
 348                 } else if (object instanceof JSFunction) {
 349                     // FIXME: use something similar to call0/call1/call2 here
 350                     JSArray arguments = new JSArray();
 351                     for(int i=0; i<numArgs; i++) arguments.addElement(i==0?a0:i==1?a1:i==2?a2:rest[i-3]);
 352                     stack.push(new CallMarker(this));
 353                     if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
 354                     stack.push(arguments);
 355                     f = (JSFunction)object;
 356                     scope = new JSScope(f.parentScope);
 357                     pc = -1;
 358                     break;
 359
 360                 } else if (object instanceof JS) {
 361                     JS c = (JS)object;
 362                     ret = method == null ? c.call(a0, a1, a2, rest, numArgs) : c.callMethod(method, a0, a1, a2, rest, numArgs);
 363
 364                 } else {
 365                     throw new JSExn("can't call a " + object + " @" + pc + "\n" + f.dump());
 366
 367                 }
 368                 if (pausecount > initialPauseCount) { pc++; return null; }
 369                 stack.push(ret);
 370                 break;
 371             }
 372
 373             case THROW:
 374                 throw new JSExn(stack.pop(), stack, f, pc, scope);
 375
 376                 /* FIXME
 377             case MAKE_GRAMMAR: {
 378                 final Grammar r = (Grammar)arg;
 379                 final JSScope final_scope = scope;
 380                 Grammar r2 = new Grammar() {
 381                         public int match(String s, int start, Hash v, JSScope scope) throws JSExn {
 382                             return r.match(s, start, v, final_scope);
 383                         }
 384                         public int matchAndWrite(String s, int start, Hash v, JSScope scope, String key) throws JSExn {
 385                             return r.matchAndWrite(s, start, v, final_scope, key);
 386                         }
 387                         public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 388                             Hash v = new Hash();
 389                             r.matchAndWrite((String)a0, 0, v, final_scope, "foo");
 390                             return v.get("foo");
 391                         }
 392                     };
 393                 Object obj = stack.pop();
 394                 if (obj != null && obj instanceof Grammar) r2 = new Grammar.Alternative((Grammar)obj, r2);
 395                 stack.push(r2);
 396                 break;
 397             }
 398                 */
 399             case ADD_TRAP: case DEL_TRAP: {
 400                 Object val = stack.pop();
 401                 Object key = stack.pop();
 402                 Object obj = stack.peek();
 403                 // A trap addition/removal
 404                 JS js = (JS) obj;
 405                 if(js instanceof JSScope) {
 406                     JSScope s = (JSScope) js;
 407                     while(s.getParentScope() != null) {
 408                         if(s.has(key)) throw new JSExn("cannot trap a variable that isn't at the top level scope");
 409                         s = s.getParentScope();
 410                     }
 411                     js = s;
 412                 }
 413                 // might want this?
 414                 // if(!js.has(key)) throw new JSExn("tried to add/remove a trap from an uninitialized variable");
 415                 if(op == ADD_TRAP) js.addTrap(key, (JSFunction)val);
 416                 else js.delTrap(key, (JSFunction)val);
 417                 break;
 418             }
 419
 420             case ASSIGN_SUB: case ASSIGN_ADD: {
 421                 Object val = stack.pop();
 422                 Object key = stack.pop();
 423                 Object obj = stack.peek();
 424                 // The following setup is VERY important. The generated bytecode depends on the stack
 425                 // being setup like this (top to bottom) KEY, OBJ, VAL, KEY, OBJ
 426                 stack.push(key);
 427                 stack.push(val);
 428                 stack.push(obj);
 429                 stack.push(key);
 430                 break;
 431             }
 432
 433             case ADD: {
 434                 int count = ((Number)arg).intValue();
 435                 if(count < 2) throw new Error("this should never happen");
 436                 if(count == 2) {
 437                     // common case
 438                     Object right = stack.pop();
 439                     Object left = stack.pop();
 440                     if(left instanceof String || right instanceof String)
 441                         stack.push(JS.toString(left).concat(JS.toString(right)));
 442                     else stack.push(JS.N(JS.toDouble(left) + JS.toDouble(right)));
 443                 } else {
 444                     Object[] args = new Object[count];
 445                     while(--count >= 0) args[count] = stack.pop();
 446                     if(args[0] instanceof String) {
 447                         StringBuffer sb = new StringBuffer(64);
 448                         for(int i=0;i<args.length;i++) sb.append(JS.toString(args[i]));
 449                         stack.push(sb.toString());
 450                     } else {
 451                         int numStrings = 0;
 452                         for(int i=0;i<args.length;i++) if(args[i] instanceof String) numStrings++;
 453                         if(numStrings == 0) {
 454                             double d = 0.0;
 455                             for(int i=0;i<args.length;i++) d += JS.toDouble(args[i]);
 456                             stack.push(JS.N(d));
 457                         } else {
 458                             int i=0;
 459                             StringBuffer sb = new StringBuffer(64);
 460                             if(!(args[0] instanceof String || args[1] instanceof String)) {
 461                                 double d=0.0;
 462                                 do {
 463                                     d += JS.toDouble(args[i++]);
 464                                 } while(!(args[i] instanceof String));
 465                                 sb.append(JS.toString(JS.N(d)));
 466                             }
 467                             while(i < args.length) sb.append(JS.toString(args[i++]));
 468                             stack.push(sb.toString());
 469                         }
 470                     }
 471                 }
 472                 break;
 473             }
 474
 475             default: {
 476                 Object right = stack.pop();
 477                 Object left = stack.pop();
 478                 switch(op) {
 479
 480                 case BITOR: stack.push(JS.N(JS.toLong(left) | JS.toLong(right))); break;
 481                 case BITXOR: stack.push(JS.N(JS.toLong(left) ^ JS.toLong(right))); break;
 482                 case BITAND: stack.push(JS.N(JS.toLong(left) & JS.toLong(right))); break;
 483
 484                 case SUB: stack.push(JS.N(JS.toDouble(left) - JS.toDouble(right))); break;
 485                 case MUL: stack.push(JS.N(JS.toDouble(left) * JS.toDouble(right))); break;
 486                 case DIV: stack.push(JS.N(JS.toDouble(left) / JS.toDouble(right))); break;
 487                 case MOD: stack.push(JS.N(JS.toDouble(left) % JS.toDouble(right))); break;
 488
 489                 case LSH: stack.push(JS.N(JS.toLong(left) << JS.toLong(right))); break;
 490                 case RSH: stack.push(JS.N(JS.toLong(left) >> JS.toLong(right))); break;
 491                 case URSH: stack.push(JS.N(JS.toLong(left) >>> JS.toLong(right))); break;
 492
 493                 case LT: case LE: case GT: case GE: {
 494                     if (left == null) left = JS.N(0);
 495                     if (right == null) right = JS.N(0);
 496                     int result = 0;
 497                     if (left instanceof String || right instanceof String) {
 498                         result = JS.toString(left).compareTo(JS.toString(right));
 499                     } else {
 500                         result = (int)java.lang.Math.ceil(JS.toDouble(left) - JS.toDouble(right));
 501                     }
 502                     stack.push(JS.B((op == LT && result < 0) || (op == LE && result <= 0) ||
 503                                (op == GT && result > 0) || (op == GE && result >= 0)));
 504                     break;
 505                 }
 506
 507                 case EQ:
 508                 case NE: {
 509                     // FIXME: This is not correct, see ECMA-262 11.9.3
 510                     Object l = left;
 511                     Object r = right;
 512                     boolean ret;
 513                     if (l == null) { Object tmp = r; r = l; l = tmp; }
 514                     if (l == null && r == null) ret = true;
 515                     else if (r == null) ret = false; // l != null, so its false
 516                     else if (l instanceof Boolean) ret = JS.B(JS.toBoolean(r)).equals(l);
 517                     else if (l instanceof Number) ret = JS.toNumber(r).doubleValue() == JS.toNumber(l).doubleValue();
 518                     else if (l instanceof String) ret = r != null && l.equals(JS.toString(r));
 519                     else ret = l.equals(r);
 520                     stack.push(JS.B(op == EQ ? ret : !ret)); break;
 521                 }
 522
 523                 default: throw new Error("unknown opcode " + op);
 524                 } }
 525             }
 526
 527         } catch(JSExn e) {
 528             while(stack.size() > 0) {
 529                 Object o = stack.pop();
 530                 if (o instanceof CatchMarker || o instanceof TryMarker) {
 531                     boolean inCatch = o instanceof CatchMarker;
 532                     if(inCatch) {
 533                         o = stack.pop();
 534                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 535                     }
 536                     if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
 537                         // run the catch block, this will implicitly run the finally block, if it exists
 538                         stack.push(o);
 539                         stack.push(catchMarker);
 540                         stack.push(e.getObject());
 541                         f = ((TryMarker)o).f;
 542                         scope = ((TryMarker)o).scope;
 543                         pc = ((TryMarker)o).catchLoc - 1;
 544                         continue OUTER;
 545                     } else {
 546                         stack.push(new FinallyData(e));
 547                         f = ((TryMarker)o).f;
 548                         scope = ((TryMarker)o).scope;
 549                         pc = ((TryMarker)o).finallyLoc - 1;
 550                         continue OUTER;
 551                     }
 552                 }
 553             }
 554             throw e;
 555         } // end try/catch
 556         } // end for
 557     }
 558
 559
 560
 561     // Markers //////////////////////////////////////////////////////////////////////
 562
 563     public static class CallMarker {
 564         int pc;
 565         JSScope scope;
 566         JSFunction f;
 567         public CallMarker(Interpreter cx) { pc = cx.pc + 1; scope = cx.scope; f = cx.f; }
 568     }
 569
 570     public static class CatchMarker { }
 571     private static CatchMarker catchMarker = new CatchMarker();
 572
 573     public static class LoopMarker {
 574         public int location;
 575         public String label;
 576         public JSScope scope;
 577         public LoopMarker(int location, String label, JSScope scope) {
 578             this.location = location;
 579             this.label = label;
 580             this.scope = scope;
 581         }
 582     }
 583     public static class TryMarker {
 584         public int catchLoc;
 585         public int finallyLoc;
 586         public JSScope scope;
 587         public JSFunction f;
 588         public TryMarker(int catchLoc, int finallyLoc, Interpreter cx) {
 589             this.catchLoc = catchLoc;
 590             this.finallyLoc = finallyLoc;
 591             this.scope = cx.scope;
 592             this.f = cx.f;
 593         }
 594     }
 595     public static class FinallyData {
 596         public int op;
 597         public Object arg;
 598         public JSExn exn;
 599         public FinallyData(int op) { this(op,null); }
 600         public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; }
 601         public FinallyData(JSExn exn) { this.exn = exn; } // Just throw this exn
 602     }
 603
 604
 605     // Operations on Primitives //////////////////////////////////////////////////////////////////////
 606
 607     static Object callMethodOnPrimitive(Object o, Object method, Object arg0, Object arg1, Object arg2, Object[] rest, int alength) throws JSExn {
 608         if (method == null || !(method instanceof String) || "".equals(method))
 609             throw new JSExn("attempt to call a non-existant method on a primitive");
 610
 611         if (o instanceof Number) {
 612             //#switch(method)
 613             case "toFixed": throw new JSExn("toFixed() not implemented");
 614             case "toExponential": throw new JSExn("toExponential() not implemented");
 615             case "toPrecision": throw new JSExn("toPrecision() not implemented");
 616             case "toString": {
 617                 int radix = alength >= 1 ? JS.toInt(arg0) : 10;
 618                 return Long.toString(((Number)o).longValue(),radix);
 619             }
 620             //#end
 621         } else if (o instanceof Boolean) {
 622             // No methods for Booleans
 623             throw new JSExn("attempt to call a method on a Boolean");
 624         }
 625
 626         String s = JS.toString(o);
 627         int slength = s.length();
 628         //#switch(method)
 629         case "substring": {
 630             int a = alength >= 1 ? JS.toInt(arg0) : 0;
 631             int b = alength >= 2 ? JS.toInt(arg1) : slength;
 632             if (a > slength) a = slength;
 633             if (b > slength) b = slength;
 634             if (a < 0) a = 0;
 635             if (b < 0) b = 0;
 636             if (a > b) { int tmp = a; a = b; b = tmp; }
 637             return s.substring(a,b);
 638         }
 639         case "substr": {
 640             int start = alength >= 1 ? JS.toInt(arg0) : 0;
 641             int len = alength >= 2 ? JS.toInt(arg1) : Integer.MAX_VALUE;
 642             if (start < 0) start = slength + start;
 643             if (start < 0) start = 0;
 644             if (len < 0) len = 0;
 645             if (len > slength - start) len = slength - start;
 646             if (len <= 0) return "";
 647             return s.substring(start,start+len);
 648         }
 649         case "charAt": {
 650             int p = alength >= 1 ? JS.toInt(arg0) : 0;
 651             if (p < 0 || p >= slength) return "";
 652             return s.substring(p,p+1);
 653         }
 654         case "charCodeAt": {
 655             int p = alength >= 1 ? JS.toInt(arg0) : 0;
 656             if (p < 0 || p >= slength) return JS.N(Double.NaN);
 657             return JS.N(s.charAt(p));
 658         }
 659         case "concat": {
 660             StringBuffer sb = new StringBuffer(slength*2).append(s);
 661             for(int i=0;i<alength;i++) sb.append(i==0?arg0:i==1?arg1:i==2?arg2:rest[i-3]);
 662             return sb.toString();
 663         }
 664         case "indexOf": {
 665             String search = alength >= 1 ? JS.toString(arg0) : "null";
 666             int start = alength >= 2 ? JS.toInt(arg1) : 0;
 667             // Java's indexOf handles an out of bounds start index, it'll return -1
 668             return JS.N(s.indexOf(search,start));
 669         }
 670         case "lastIndexOf": {
 671             String search = alength >= 1 ? JS.toString(arg0) : "null";
 672             int start = alength >= 2 ? JS.toInt(arg1) : 0;
 673             // Java's indexOf handles an out of bounds start index, it'll return -1
 674             return JS.N(s.lastIndexOf(search,start));
 675         }
 676         case "match": return JSRegexp.stringMatch(s,arg0);
 677         case "replace": return JSRegexp.stringReplace(s,arg0,arg1);
 678         case "search": return JSRegexp.stringSearch(s,arg0);
 679         case "split": return JSRegexp.stringSplit(s,arg0,arg1,alength);
 680         case "toLowerCase": return s.toLowerCase();
 681         case "toUpperCase": return s.toUpperCase();
 682         case "toString": return s;
 683         case "slice": {
 684             int a = alength >= 1 ? JS.toInt(arg0) : 0;
 685             int b = alength >= 2 ? JS.toInt(arg1) : slength;
 686             if (a < 0) a = slength + a;
 687             if (b < 0) b = slength + b;
 688             if (a < 0) a = 0;
 689             if (b < 0) b = 0;
 690             if (a > slength) a = slength;
 691             if (b > slength) b = slength;
 692             if (a > b) return "";
 693             return s.substring(a,b);
 694         }
 695         //#end
 696         throw new JSExn("Attempted to call non-existent method: " + method);
 697     }
 698
 699     static Object getFromPrimitive(Object o, Object key) throws JSExn {
 700         boolean returnJS = false;
 701         if (o instanceof Boolean) {
 702             throw new JSExn("Booleans do not have properties");
 703         } else if (o instanceof Number) {
 704             if (key.equals("toPrecision") || key.equals("toExponential") || key.equals("toFixed"))
 705                 returnJS = true;
 706         }
 707         if (!returnJS) {
 708             // the string stuff applies to everything
 709             String s = JS.toString(o);
 710
 711             // this is sort of ugly, but this list should never change
 712             // These should provide a complete (enough) implementation of the ECMA-262 String object
 713
 714             //#switch(key)
 715             case "length": return JS.N(s.length());
 716             case "substring": returnJS = true; break;
 717             case "charAt": returnJS = true; break;
 718             case "charCodeAt": returnJS = true; break;
 719             case "concat": returnJS = true; break;
 720             case "indexOf": returnJS = true; break;
 721             case "lastIndexOf": returnJS = true; break;
 722             case "match": returnJS = true; break;
 723             case "replace": returnJS = true; break;
 724             case "search": returnJS = true; break;
 725             case "slice": returnJS = true; break;
 726             case "split": returnJS = true; break;
 727             case "toLowerCase": returnJS = true; break;
 728             case "toUpperCase": returnJS = true; break;
 729             case "toString": returnJS = true; break;
 730             case "substr": returnJS = true; break;
 731            //#end
 732         }
 733         if (returnJS) {
 734             final Object target = o;
 735             final String method = JS.toString(o);
 736             return new JS() {
 737                     public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 738                         if (nargs > 2) throw new JSExn("cannot call that method with that many arguments");
 739                         return callMethodOnPrimitive(target, method, a0, a1, a2, rest, nargs);
 740                     }
 741             };
 742         }
 743         return null;
 744     }
 745
 746     private static class Stub extends JS {
 747         private Object method;
 748         JS obj;
 749         public Stub(JS obj, Object method) { this.obj = obj; this.method = method; }
 750         public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
 751             return ((JS)obj).callMethod(method, a0, a1, a2, rest, nargs);
 752         }
 753     }
 754 }