jsexn.c

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     * so we can suppress any checkAccess failures.  Such failures should stop
     * the backtrace procedure, not result in a failure of this constructor.
     */
    checkAccess = cx->runtime->checkObjectAccess;
    if (checkAccess) {
        older = JS_SetErrorReporter(cx, NULL);
        state = JS_SaveExceptionState(cx);
    }
#ifdef __GNUC__         /* suppress bogus gcc warnings */
    else {
        older = NULL;
        state = NULL;
    }
#endif
    callerid = ATOM_KEY(cx->runtime->atomState.callerAtom);

    /*
     * Prepare to allocate a jschar buffer at stackbuf, where stacklen indexes
     * the next free jschar slot, and with room for at most stackmax non-null
     * jschars.  If stackbuf is non-null, it always contains an extra slot for
     * the null terminator we'll store at the end, as a backstop.
     *
     * All early returns must goto done after this point, till the after-loop
     * cleanup code has run!
     */
    stackbuf = NULL;
    stacklen = stackmax = 0;
    ok = JS_TRUE;

#define APPEND_CHAR_TO_STACK(c)                                               \
    JS_BEGIN_MACRO                                                            \
        if (stacklen == stackmax) {                                           \
            void *ptr_;                                                       \
            stackmax = stackmax ? 2 * stackmax : 64;                          \
            ptr_ = JS_realloc(cx, stackbuf, (stackmax+1) * sizeof(jschar));   \
            if (!ptr_) {                                                      \
                ok = JS_FALSE;                                                \
                goto done;                                                    \
            }                                                                 \
            stackbuf = ptr_;                                                  \
        }                                                                     \
        stackbuf[stacklen++] = (c);                                           \
    JS_END_MACRO

#define APPEND_STRING_TO_STACK(str)                                           \
    JS_BEGIN_MACRO                                                            \
        JSString *str_ = str;                                                 \
        size_t length_ = JSSTRING_LENGTH(str_);                               \
        if (stacklen + length_ > stackmax) {                                  \
            void *ptr_;                                                       \
            stackmax = JS_BIT(JS_CeilingLog2(stacklen + length_));            \
            ptr_ = JS_realloc(cx, stackbuf, (stackmax+1) * sizeof(jschar));   \
            if (!ptr_) {                                                      \
                ok = JS_FALSE;                                                \
                goto done;                                                    \
            }                                                                 \
            stackbuf = ptr_;                                                  \
        }                                                                     \
        js_strncpy(stackbuf + stacklen, JSSTRING_CHARS(str_), length_);       \
        stacklen += length_;                                                  \
    JS_END_MACRO

    for (fp = cx->fp; fp; fp = fp->down) {
        if (checkAccess) {
            v = (fp->fun && fp->argv) ? fp->argv[-2] : JSVAL_NULL;
            if (!JSVAL_IS_PRIMITIVE(v)) {
                ok = checkAccess(cx, fp->fun->object, callerid, JSACC_READ, &v);
                if (!ok) {
                    ok = JS_TRUE;
                    break;
                }
            }
        }

        if (fp->fun) {
            if (fp->fun->atom)
                APPEND_STRING_TO_STACK(ATOM_TO_STRING(fp->fun->atom));

            APPEND_CHAR_TO_STACK('(');
            for (i = 0; i < fp->argc; i++) {
                /* Avoid toSource bloat and fallibility for object types. */
                v = fp->argv[i];
                if (JSVAL_IS_PRIMITIVE(v)) {
                    argsrc = js_ValueToSource(cx, v);
                } else if (JSVAL_IS_FUNCTION(cx, v)) {
                    /* XXX Avoid function decompilation bloat for now. */
                    argsrc = JS_GetFunctionId(JS_ValueToFunction(cx, v));
                    if (!argsrc)
                        argsrc = js_ValueToSource(cx, v);
                } else {
                    /* XXX Avoid toString on objects, it takes too long and
                           uses too much memory, for too many classes (see
                           Mozilla bug 166743). */
                    char buf[100];
                    JS_snprintf(buf, sizeof buf, "[object %s]",
                                OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(v))->name);
                    argsrc = JS_NewStringCopyZ(cx, buf);
                }
                if (!argsrc) {
                    ok = JS_FALSE;
                    goto done;
                }
                if (i > 0)
                    APPEND_CHAR_TO_STACK(',');
                APPEND_STRING_TO_STACK(argsrc);
            }
            APPEND_CHAR_TO_STACK(')');
        }

        APPEND_CHAR_TO_STACK('@');
        if (fp->script && fp->script->filename) {
            for (cp = fp->script->filename; *cp; cp++)
                APPEND_CHAR_TO_STACK(*cp);
        }
        APPEND_CHAR_TO_STACK(':');
        if (fp->script && fp->pc) {
            ulineno = js_PCToLineNumber(cx, fp->script, fp->pc);
            JS_snprintf(ulnbuf, sizeof ulnbuf, "%u", ulineno);
            for (cp = ulnbuf; *cp; cp++)
                APPEND_CHAR_TO_STACK(*cp);
        } else {
            APPEND_CHAR_TO_STACK('0');
        }
        APPEND_CHAR_TO_STACK('\n');
    }

#undef APPEND_CHAR_TO_STACK
#undef APPEND_STRING_TO_STACK

done:
    if (checkAccess) {
        if (ok)
            JS_RestoreExceptionState(cx, state);
        else
            JS_DropExceptionState(cx, state);
        JS_SetErrorReporter(cx, older);
    }
    if (!ok) {
        JS_free(cx, stackbuf);
        return JS_FALSE;
    }

    if (!stackbuf) {
        stack = cx->runtime->emptyString;
    } else {
        /* NB: if stackbuf was allocated, it has room for the terminator. */
        JS_ASSERT(stacklen <= stackmax);
        if (stacklen < stackmax) {
            /*
             * Realloc can fail when shrinking on some FreeBSD versions, so
             * don't use JS_realloc here; simply let the oversized allocation
             * be owned by the string in that rare case.
             */
            void *shrunk = realloc(stackbuf, (stacklen+1) * sizeof(jschar));
            if (shrunk)
                stackbuf = shrunk;
        }
        stackbuf[stacklen] = 0;
        stack = js_NewString(cx, stackbuf, stacklen, 0);
        if (!stack) {
            JS_free(cx, stackbuf);
            return JS_FALSE;
        }
    }
    return JS_DefineProperty(cx, obj, js_stack_str,
                             STRING_TO_JSVAL(stack),
                             NULL, NULL, JSPROP_ENUMERATE);
}

static JSBool
Exception(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    JSBool ok;
    jsval pval;
    int32 lineno;
    JSString *message, *filename;

    if (cx->creatingException)
        return JS_FALSE;
    cx->creatingException = JS_TRUE;

    if (!(cx->fp->flags & JSFRAME_CONSTRUCTING)) {
        /*
         * ECMA ed. 3, 15.11.1 requires Error, etc., to construct even when
         * called as functions, without operator new.  But as we do not give
         * each constructor a distinct JSClass, whose .name member is used by
         * js_NewObject to find the class prototype, we must get the class
         * prototype ourselves.
         */
        ok = OBJ_GET_PROPERTY(cx, JSVAL_TO_OBJECT(argv[-2]),
                              (jsid)cx->runtime->atomState.classPrototypeAtom,
                              &pval);
        if (!ok)
            goto out;
        obj = js_NewObject(cx, &ExceptionClass, JSVAL_TO_OBJECT(pval), NULL);
        if (!obj) {
            ok = JS_FALSE;
            goto out;
        }
        *rval = OBJECT_TO_JSVAL(obj);
    }

    /*
     * If it's a new object of class Exception, then null out the private
     * data so that the finalizer doesn't attempt to free it.
     */
    if (OBJ_GET_CLASS(cx, obj) == &ExceptionClass)
        OBJ_SET_SLOT(cx, obj, JSSLOT_PRIVATE, JSVAL_VOID);

    /* Set the 'message' property. */
    if (argc != 0) {
        message = js_ValueToString(cx, argv[0]);
        if (!message) {
            ok = JS_FALSE;
            goto out;
        }
    } else {
        message = cx->runtime->emptyString;
    }

    /* Set the 'fileName' property. */
    if (argc > 1) {
        filename = js_ValueToString(cx, argv[1]);
        if (!filename) {
            ok = JS_FALSE;
            goto out;
        }
    } else {
        filename = cx->runtime->emptyString;
    }

    /* Set the 'lineNumber' property. */
    if (argc > 2) {
        ok = js_ValueToInt32(cx, argv[2], &lineno);
        if (!ok)
            goto out;
    } else {
        lineno = 0;
    }

    ok = InitExceptionObject(cx, obj, message, filename, lineno);

out:
    cx->creatingException = JS_FALSE;
    return ok;
}

/*
 * Convert to string.
 *
 * This method only uses JavaScript-modifiable properties name, message.  It
 * is left to the host to check for private data and report filename and line
 * number information along with this message.
 */
static JSBool
exn_toString(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    jsval v;
    JSString *name, *message, *result;
    jschar *chars, *cp;
    size_t name_length, message_length, length;

    if (!OBJ_GET_PROPERTY(cx, obj, (jsid)cx->runtime->atomState.nameAtom, &v))
        return JS_FALSE;
    name = js_ValueToString(cx, v);
    if (!name)
        return JS_FALSE;

    if (!JS_GetProperty(cx, obj, js_message_str, &v) ||
        !(message = js_ValueToString(cx, v))) {
        return JS_FALSE;
    }

    if (JSSTRING_LENGTH(message) != 0) {
        name_length = JSSTRING_LENGTH(name);
        message_length = JSSTRING_LENGTH(message);
        length = name_length + message_length + 2;
        cp = chars = (jschar*) JS_malloc(cx, (length + 1) * sizeof(jschar));
        if (!chars)
            return JS_FALSE;

        js_strncpy(cp, JSSTRING_CHARS(name), name_length);
        cp += name_length;
        *cp++ = ':'; *cp++ = ' ';
        js_strncpy(cp, JSSTRING_CHARS(message), message_length);
        cp += message_length;
        *cp = 0;

        result = js_NewString(cx, chars, length, 0);
        if (!result) {
            JS_free(cx, chars);
            return JS_FALSE;
        }
    } else {
        result = name;
    }

    *rval = STRING_TO_JSVAL(result);
    return JS_TRUE;
}

#if JS_HAS_TOSOURCE
/*
 * Return a string that may eval to something similar to the original object.
 */
static JSBool
exn_toSource(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    jsval v;
    JSString *name, *message, *filename, *lineno_as_str, *result;
    int32 lineno;
    size_t lineno_length, name_length, message_length, filename_length, length;
    jschar *chars, *cp;

    if (!OBJ_GET_PROPERTY(cx, obj, (jsid)cx->runtime->atomState.nameAtom, &v))
        return JS_FALSE;
    name = js_ValueToString(cx, v);
    if (!name)
        return JS_FALSE;

    if (!JS_GetProperty(cx, obj, js_message_str, &v) ||
        !(message = js_ValueToSource(cx, v))) {
        return JS_FALSE;
    }

    if (!JS_GetProperty(cx, obj, js_filename_str, &v) ||
        !(filename = js_ValueToSource(cx, v))) {
        return JS_FALSE;
    }

    if (!JS_GetProperty(cx, obj, js_lineno_str, &v) ||
        !js_ValueToInt32 (cx, v, &lineno)) {
        return JS_FALSE;
    }

    if (lineno != 0) {
        if (!(lineno_as_str = js_ValueToString(cx, v))) {
            return JS_FALSE;
        }
        lineno_length = JSSTRING_LENGTH(lineno_as_str);
    } else {
        lineno_as_str = NULL;
        lineno_length = 0;
    }

    /* Magic 8, for the characters in ``(new ())''. */
    name_length = JSSTRING_LENGTH(name);
    message_length = JSSTRING_LENGTH(message);
    length = 8 + name_length + message_length;

    filename_length = JSSTRING_LENGTH(filename);
    if (filename_length != 0) {
        /* append filename as ``, {filename}'' */
        length += 2 + filename_length;
        if (lineno_as_str) {
            /* append lineno as ``, {lineno_as_str}'' */
            length += 2 + lineno_length;
        }
    } else {
        if (lineno_as_str) {
            /*