jsopcode.c

一个基于alice开发的机器人

                todo = -2;
                break;
            }

              case JSOP_SWAP:
                /*
                 * We don't generate this opcode currently, and previously we
                 * did not need to decompile it.  If old, serialized bytecode
                 * uses it still, we should fall through and set todo = -2.
                 */
                /* FALL THROUGH */

              case JSOP_GOSUB:
              case JSOP_GOSUBX:
                /*
                 * JSOP_GOSUB and GOSUBX have no effect on the decompiler's
                 * string stack because the next op in bytecode order finds
                 * the stack balanced by a JSOP_RETSUB executed elsewhere.
                 */
                todo = -2;
                break;

              case JSOP_SETSP:
                /*
                 * The compiler models operand stack depth and fixes the stack
                 * pointer on entry to a catch clause based on its depth model.
                 * The decompiler must match the code generator's model, which
                 * is why JSOP_FINALLY pushes a cookie that JSOP_RETSUB pops.
                 */
                ss->top = (uintN) GET_ATOM_INDEX(pc);
                break;

              case JSOP_EXCEPTION:
                /*
                 * The only other JSOP_EXCEPTION case occurs as part of a code
                 * sequence that follows a SRC_CATCH-annotated JSOP_NOP.
                 */
                sn = js_GetSrcNote(jp->script, pc);
                LOCAL_ASSERT(sn && SN_TYPE(sn) == SRC_HIDDEN);
                todo = -2;
                break;
#endif /* JS_HAS_EXCEPTIONS */

              case JSOP_POP:
              case JSOP_POPV:
                sn = js_GetSrcNote(jp->script, pc);
                switch (sn ? SN_TYPE(sn) : SRC_NULL) {
                  case SRC_FOR:
                    rval = POP_STR();
                    todo = -2;
                    goto do_forloop;

                  case SRC_PCDELTA:
                    /* Pop and save to avoid blowing stack depth budget. */
                    lval = JS_strdup(cx, POP_STR());
                    if (!lval)
                        return JS_FALSE;

                    /*
                     * The offset tells distance to the end of the right-hand
                     * operand of the comma operator.
                     */
                    done = pc + len;
                    pc += js_GetSrcNoteOffset(sn, 0);
                    len = 0;

                    if (!Decompile(ss, done, pc - done)) {
                        JS_free(cx, (char *)lval);
                        return JS_FALSE;
                    }

                    /* Pop Decompile result and print comma expression. */
                    rval = POP_STR();
                    todo = Sprint(&ss->sprinter, "%s, %s", lval, rval);
                    JS_free(cx, (char *)lval);
                    break;

                  case SRC_HIDDEN:
                    /* Hide this pop, it's from a goto in a with or for/in. */
                    todo = -2;
                    break;

                  default:
                    rval = POP_STR();
                    if (*rval != '\0')
                        js_printf(jp, "\t%s;\n", rval);
                    todo = -2;
                    break;
                }
                break;

              case JSOP_POP2:
                (void) PopOff(ss, op);
                (void) PopOff(ss, op);
                todo = -2;
                break;

            {
              static const char with_cookie[] = "with-cookie";

              case JSOP_ENTERWITH:
                sn = js_GetSrcNote(jp->script, pc);
                if (sn && SN_TYPE(sn) == SRC_HIDDEN) {
                    todo = -2;
                    break;
                }
                rval = POP_STR();
                js_printf(jp, "\twith (%s) {\n", rval);
                jp->indent += 4;
                todo = Sprint(&ss->sprinter, with_cookie);
                break;

              case JSOP_LEAVEWITH:
                sn = js_GetSrcNote(jp->script, pc);
                todo = -2;
                if (sn && SN_TYPE(sn) == SRC_HIDDEN)
                    break;
                rval = POP_STR();
                LOCAL_ASSERT(strcmp(rval, with_cookie) == 0);
                jp->indent -= 4;
                js_printf(jp, "\t}\n");
                break;
            }

              case JSOP_SETRVAL:
              case JSOP_RETURN:
                rval = POP_STR();
                if (*rval != '\0')
                    js_printf(jp, "\t%s %s;\n", cs->name, rval);
                else
                    js_printf(jp, "\t%s;\n", cs->name);
                todo = -2;
                break;

#if JS_HAS_EXCEPTIONS
              case JSOP_THROW:
                sn = js_GetSrcNote(jp->script, pc);
                todo = -2;
                if (sn && SN_TYPE(sn) == SRC_HIDDEN)
                    break;
                rval = POP_STR();
                js_printf(jp, "\t%s %s;\n", cs->name, rval);
                break;
#endif /* JS_HAS_EXCEPTIONS */

              case JSOP_GOTO:
              case JSOP_GOTOX:
                sn = js_GetSrcNote(jp->script, pc);
                switch (sn ? SN_TYPE(sn) : SRC_NULL) {
                  case SRC_CONT2LABEL:
                    atom = js_GetAtom(cx, &jp->script->atomMap,
                                      (jsatomid) js_GetSrcNoteOffset(sn, 0));
                    rval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom), 0);
                    if (!rval)
                        return JS_FALSE;
                    RETRACT(&ss->sprinter, rval);
                    js_printf(jp, "\tcontinue %s;\n", rval);
                    break;
                  case SRC_CONTINUE:
                    js_printf(jp, "\tcontinue;\n");
                    break;
                  case SRC_BREAK2LABEL:
                    atom = js_GetAtom(cx, &jp->script->atomMap,
                                      (jsatomid) js_GetSrcNoteOffset(sn, 0));
                    rval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom), 0);
                    if (!rval)
                        return JS_FALSE;
                    RETRACT(&ss->sprinter, rval);
                    js_printf(jp, "\tbreak %s;\n", rval);
                    break;
                  case SRC_HIDDEN:
                    break;
                  default:
                    js_printf(jp, "\tbreak;\n");
                    break;
                }
                todo = -2;
                break;

              case JSOP_IFEQ:
              case JSOP_IFEQX:
                len = GetJumpOffset(pc, pc);
                sn = js_GetSrcNote(jp->script, pc);

                switch (sn ? SN_TYPE(sn) : SRC_NULL) {
                  case SRC_IF:
                  case SRC_IF_ELSE:
                    rval = POP_STR();
                    js_printf(jp, "\tif (%s) {\n", rval);
                    jp->indent += 4;
                    if (SN_TYPE(sn) == SRC_IF) {
                        DECOMPILE_CODE(pc + oplen, len - oplen);
                    } else {
                        len = js_GetSrcNoteOffset(sn, 0);
                        DECOMPILE_CODE(pc + oplen, len - oplen);
                        jp->indent -= 4;
                        pc += len;
                        LOCAL_ASSERT(*pc == JSOP_GOTO || *pc == JSOP_GOTOX);
                        oplen = js_CodeSpec[*pc].length;
                        len = GetJumpOffset(pc, pc);
                        js_printf(jp, "\t} else {\n");
                        jp->indent += 4;
                        DECOMPILE_CODE(pc + oplen, len - oplen);
                    }
                    jp->indent -= 4;
                    js_printf(jp, "\t}\n");
                    todo = -2;
                    break;

                  case SRC_WHILE:
                    rval = POP_STR();
                    js_printf(jp, "\twhile (%s) {\n", rval);
                    jp->indent += 4;
                    tail = js_GetSrcNoteOffset(sn, 0);
                    DECOMPILE_CODE(pc + oplen, tail - oplen);
                    jp->indent -= 4;
                    js_printf(jp, "\t}\n");
                    todo = -2;
                    break;

                  case SRC_COND:
                    xval = JS_strdup(cx, POP_STR());
                    if (!xval)
                        return JS_FALSE;
                    len = js_GetSrcNoteOffset(sn, 0);
                    DECOMPILE_CODE(pc + oplen, len - oplen);
                    lval = JS_strdup(cx, POP_STR());
                    if (!lval) {
                        JS_free(cx, (void *)xval);
                        return JS_FALSE;
                    }
                    pc += len;
                    LOCAL_ASSERT(*pc == JSOP_GOTO || *pc == JSOP_GOTOX);
                    oplen = js_CodeSpec[*pc].length;
                    len = GetJumpOffset(pc, pc);
                    DECOMPILE_CODE(pc + oplen, len - oplen);
                    rval = POP_STR();
                    todo = Sprint(&ss->sprinter, "%s ? %s : %s",
                                  xval, lval, rval);
                    JS_free(cx, (void *)xval);
                    JS_free(cx, (void *)lval);
                    break;

                  default:
                    break;
                }
                break;

              case JSOP_IFNE:
              case JSOP_IFNEX:
#if JS_HAS_DO_WHILE_LOOP
                /* Currently, this must be a do-while loop's upward branch. */
                jp->indent -= 4;
                js_printf(jp, "\t} while (%s);\n", POP_STR());
                todo = -2;
#else
                JS_ASSERT(0);
#endif /* JS_HAS_DO_WHILE_LOOP */
                break;

              case JSOP_OR:
              case JSOP_ORX:
                xval = "||";

              do_logical_connective:
                /* Top of stack is the first clause in a disjunction (||). */
                lval = JS_strdup(cx, POP_STR());
                if (!lval)
                    return JS_FALSE;
                done = pc + GetJumpOffset(pc, pc);
                pc += len;
                len = PTRDIFF(done, pc, jsbytecode);
                DECOMPILE_CODE(pc, len);
                rval = POP_STR();
                if (jp->pretty &&
                    jp->indent + 4 + strlen(lval) + 4 + strlen(rval) > 75) {
                    rval = JS_strdup(cx, rval);
                    if (!rval) {
                        tail = -1;
                    } else {
                        todo = Sprint(&ss->sprinter, "%s %s\n", lval, xval);
                        tail = Sprint(&ss->sprinter, "%*s%s",
                                      jp->indent + 4, "", rval);
                        JS_free(cx, (char *)rval);
                    }
                    if (tail < 0)
                        todo = -1;
                } else {
                    todo = Sprint(&ss->sprinter, "%s %s %s", lval, xval, rval);
                }
                JS_free(cx, (char *)lval);
                break;

              case JSOP_AND:
              case JSOP_ANDX:
                xval = "&&";
                goto do_logical_connective;

              case JSOP_FORARG:
                atom = GetSlotAtom(jp, js_GetArgument, GET_ARGNO(pc));
                LOCAL_ASSERT(atom);
                goto do_fornameinloop;

              case JSOP_FORVAR:
                atom = GetSlotAtom(jp, js_GetLocalVariable, GET_VARNO(pc));
                LOCAL_ASSERT(atom);
                goto do_fornameinloop;

              case JSOP_FORNAME:
                atom = GET_ATOM(cx, jp->script, pc);

              do_fornameinloop:
                sn = js_GetSrcNote(jp->script, pc);
                xval = NULL;
                lval = "";
                goto do_forinloop;

              case JSOP_FORPROP:
                xval = NULL;
                atom = GET_ATOM(cx, jp->script, pc);
                if (ATOM_KEYWORD(atom)) {
                    xval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom),
                                       (jschar)'\'');
                    if (!xval)
                        return JS_FALSE;
                    atom = NULL;
                }
                lval = POP_STR();
                sn = NULL;

              do_forinloop:
                pc += oplen;
                LOCAL_ASSERT(*pc == JSOP_IFEQ || *pc == JSOP_IFEQX);
                oplen = js_CodeSpec[*pc].length;
                len = GetJumpOffset(pc, pc);
                sn2 = js_GetSrcNote(jp->script, pc);
                tail = js_GetSrcNoteOffset(sn2, 0);

              do_forinbody:
                js_printf(jp, "\tfor (%s%s", VarPrefix(sn), lval);
                if (atom) {
                    xval = QuoteString(&ss->sprinter, ATOM_TO_STRING(atom), 0);
                    if (!xval)
                        return JS_FALSE;
                    RETRACT(&ss->sprinter, xval);
                    js_printf(jp, *lval ? ".%s" : "%s", xval);
                } else if (xval) {
                    js_printf(jp, "[%s]", xval);
                }
                rval = OFF2STR(&ss->sprinter, ss->offsets[ss->top-1]);
                js_printf(jp, " in %s) {\n", rval);
                jp->indent += 4;
                DECOMPILE_CODE(pc + oplen, tail - oplen);
                jp->indent -= 4;
                js_printf(jp, "\t}\n");
                todo = -2;
                break;

              case JSOP_FORELEM:
                pc++;
                LOCAL_ASSERT(*pc == JSOP_IFEQ || *pc == JSOP_IFEQX);
                len = js_CodeSpec[*pc].length;

                /*
                 * Arrange for the JSOP_ENUMELEM case to set tail for use by
                 * do_forinbody: code that uses on it to find the loop-closing
                 * jump (whatever its format, normal or extended), in order to
                 * bound the recursively decompiled loop body.
                 */
                sn = js_GetSrcNote(jp->script, pc);
                JS_ASSERT(!forelem_tail);
                forelem_tail = pc + js_GetSrcNoteOffset(sn, 0);

                /*
                 * This gets a little wacky.  Only the length of the for loop