jsexn.c

Swfdec still is development software, but has also followed a rigid no-crashes-allowed policy. I b

             * no filename, but have line number,
             * need to append ``, "", {lineno_as_str}''
             */
            length += 6 + lineno_length;
        }
    }

    cp = chars = (jschar*) JS_malloc(cx, (length + 1) * sizeof(jschar));
    if (!chars)
        return JS_FALSE;

    *cp++ = '('; *cp++ = 'n'; *cp++ = 'e'; *cp++ = 'w'; *cp++ = ' ';
    js_strncpy(cp, JSSTRING_CHARS(name), name_length);
    cp += name_length;
    *cp++ = '(';
    if (message_length != 0) {
        js_strncpy(cp, JSSTRING_CHARS(message), message_length);
        cp += message_length;
    }

    if (filename_length != 0) {
        /* append filename as ``, {filename}'' */
        *cp++ = ','; *cp++ = ' ';
        js_strncpy(cp, JSSTRING_CHARS(filename), filename_length);
        cp += filename_length;
    } else {
        if (lineno_as_str) {
            /*
             * no filename, but have line number,
             * need to append ``, "", {lineno_as_str}''
             */
            *cp++ = ','; *cp++ = ' '; *cp++ = '"'; *cp++ = '"';
        }
    }
    if (lineno_as_str) {
        /* append lineno as ``, {lineno_as_str}'' */
        *cp++ = ','; *cp++ = ' ';
        js_strncpy(cp, JSSTRING_CHARS(lineno_as_str), lineno_length);
        cp += lineno_length;
    }

    *cp++ = ')'; *cp++ = ')'; *cp = 0;

    result = js_NewString(cx, chars, length, 0);
    if (!result) {
        JS_free(cx, chars);
        return JS_FALSE;
    }
    *rval = STRING_TO_JSVAL(result);
    return JS_TRUE;
}
#endif

static JSFunctionSpec exception_methods[] = {
#if JS_HAS_TOSOURCE
    {js_toSource_str,   exn_toSource,           0,0,0},
#endif
    {js_toString_str,   exn_toString,           0,0,0},
    {0,0,0,0,0}
};

JSObject *
js_InitExceptionClasses(JSContext *cx, JSObject *obj)
{
    int i;
    JSObject *protos[JSEXN_LIMIT];

    /* Initialize the prototypes first. */
    for (i = 0; exceptions[i].name != 0; i++) {
        JSAtom *atom;
        JSFunction *fun;
        JSString *nameString;
        int protoIndex = exceptions[i].protoIndex;

        /* Make the prototype for the current constructor name. */
        protos[i] = js_NewObject(cx, &ExceptionClass,
                                 (protoIndex != JSEXN_NONE)
                                 ? protos[protoIndex]
                                 : NULL,
                                 obj);
        if (!protos[i])
            return NULL;

        /* So exn_finalize knows whether to destroy private data. */
        OBJ_SET_SLOT(cx, protos[i], JSSLOT_PRIVATE, JSVAL_VOID);

        atom = js_Atomize(cx, exceptions[i].name, strlen(exceptions[i].name), 0);
        if (!atom)
            return NULL;

        /* Make a constructor function for the current name. */
        fun = js_DefineFunction(cx, obj, atom, exceptions[i].native, 3, 0);
        if (!fun)
            return NULL;

        /* Make this constructor make objects of class Exception. */
        fun->clasp = &ExceptionClass;

        /* Make the prototype and constructor links. */
        if (!js_SetClassPrototype(cx, fun->object, protos[i],
                                  JSPROP_READONLY | JSPROP_PERMANENT)) {
            return NULL;
        }

        /* proto bootstrap bit from JS_InitClass omitted. */
        nameString = JS_NewStringCopyZ(cx, exceptions[i].name);
        if (!nameString)
            return NULL;

        /* Add the name property to the prototype. */
        if (!JS_DefineProperty(cx, protos[i], js_name_str,
                               STRING_TO_JSVAL(nameString),
                               NULL, NULL,
                               JSPROP_ENUMERATE)) {
            return NULL;
        }
    }

    /*
     * Add an empty message property.  (To Exception.prototype only,
     * because this property will be the same for all the exception
     * protos.)
     */
    if (!JS_DefineProperty(cx, protos[0], js_message_str,
                           STRING_TO_JSVAL(cx->runtime->emptyString),
                           NULL, NULL, JSPROP_ENUMERATE)) {
        return NULL;
    }
    if (!JS_DefineProperty(cx, protos[0], js_filename_str,
                           STRING_TO_JSVAL(cx->runtime->emptyString),
                           NULL, NULL, JSPROP_ENUMERATE)) {
        return NULL;
    }
    if (!JS_DefineProperty(cx, protos[0], js_lineno_str,
                           INT_TO_JSVAL(0),
                           NULL, NULL, JSPROP_ENUMERATE)) {
        return NULL;
    }

    /*
     * Add methods only to Exception.prototype, because ostensibly all
     * exception types delegate to that.
     */
    if (!JS_DefineFunctions(cx, protos[0], exception_methods))
        return NULL;

    return protos[0];
}

static JSExnType errorToExceptionNum[] = {
#define MSG_DEF(name, number, count, exception, format) \
    exception,
#include "js.msg"
#undef MSG_DEF
};

#if defined ( DEBUG_mccabe ) && defined ( PRINTNAMES )
/* For use below... get character strings for error name and exception name */
static struct exnname { char *name; char *exception; } errortoexnname[] = {
#define MSG_DEF(name, number, count, exception, format) \
    {#name, #exception},
#include "js.msg"
#undef MSG_DEF
};
#endif /* DEBUG */

JSBool
js_ErrorToException(JSContext *cx, const char *message, JSErrorReport *reportp)
{
    JSErrNum errorNumber;
    JSExnType exn;
    JSBool ok;
    JSObject *errProto, *errObject;
    JSString *messageStr, *filenameStr;
    uintN lineno;
    JSExnPrivate *privateData;

    /*
     * Tell our caller to report immediately if cx has no active frames, or if
     * this report is just a warning.
     */
    JS_ASSERT(reportp);
    if (!cx->fp || JSREPORT_IS_WARNING(reportp->flags))
        return JS_FALSE;

    /* Find the exception index associated with this error. */
    errorNumber = (JSErrNum) reportp->errorNumber;
    exn = errorToExceptionNum[errorNumber];
    JS_ASSERT(exn < JSEXN_LIMIT);

#if defined( DEBUG_mccabe ) && defined ( PRINTNAMES )
    /* Print the error name and the associated exception name to stderr */
    fprintf(stderr, "%s\t%s\n",
            errortoexnname[errorNumber].name,
            errortoexnname[errorNumber].exception);
#endif

    /*
     * Return false (no exception raised) if no exception is associated
     * with the given error number.
     */
    if (exn == JSEXN_NONE)
        return JS_FALSE;

    /*
     * Prevent runaway recursion, just as the Exception native constructor
     * must do, via cx->creatingException.  If an out-of-memory error occurs,
     * no exception object will be created, but we don't assume that OOM is
     * the only kind of error that subroutines of this function called below
     * might raise.
     */
    if (cx->creatingException)
        return JS_FALSE;
    cx->creatingException = JS_TRUE;

    /*
     * Try to get an appropriate prototype by looking up the corresponding
     * exception constructor name in the scope chain of the current context's
     * top stack frame, or in the global object if no frame is active.
     *
     * XXXbe hack around JSCLASS_NEW_RESOLVE code in js_LookupProperty that
     *       checks cx->fp, cx->fp->pc, and js_CodeSpec[*cx->fp->pc] in order
     *       to compute resolve flags such as JSRESOLVE_ASSIGNING.  The bug
     *       is that this "internal" js_GetClassPrototype call may trigger a
     *       resolve of exceptions[exn].name if the global object uses a lazy
     *       standard class resolver (see JS_ResolveStandardClass), but the
     *       current frame and bytecode end up affecting the resolve flags.
     */
    {
        JSStackFrame *fp = cx->fp;
        jsbytecode *pc = NULL;

        if (fp) {
            pc = fp->pc;
            fp->pc = NULL;
        }
        ok = js_GetClassPrototype(cx, exceptions[exn].name, &errProto);
        if (pc)
            fp->pc = pc;
        if (!ok)
            goto out;
    }

    errObject = js_NewObject(cx, &ExceptionClass, errProto, NULL);
    if (!errObject) {
        ok = JS_FALSE;
        goto out;
    }

    /*
     * Set the generated Exception object early, so it won't be GC'd by a last
     * ditch attempt to collect garbage, or a GC that otherwise nests or races
     * under any of the following calls.  If one of the following calls fails,
     * it will overwrite this exception object with one of its own (except in
     * case of OOM errors, of course).
     */
    JS_SetPendingException(cx, OBJECT_TO_JSVAL(errObject));

    messageStr = JS_NewStringCopyZ(cx, message);
    if (!messageStr) {
        ok = JS_FALSE;
        goto out;
    }

    if (reportp) {
        filenameStr = JS_NewStringCopyZ(cx, reportp->filename);
        if (!filenameStr) {
            ok = JS_FALSE;
            goto out;
        }
        lineno = reportp->lineno;
    } else {
        filenameStr = cx->runtime->emptyString;
        lineno = 0;
    }
    ok = InitExceptionObject(cx, errObject, messageStr, filenameStr, lineno);
    if (!ok)
        goto out;

    /*
     * Construct a new copy of the error report struct, and store it in the
     * exception object's private data.  We can't use the error report struct
     * that was passed in, because it's stack-allocated, and also because it
     * may point to transient data in the JSTokenStream.
     */
    privateData = exn_newPrivate(cx, reportp);
    if (!privateData) {
        ok = JS_FALSE;
        goto out;
    }
    OBJ_SET_SLOT(cx, errObject, JSSLOT_PRIVATE, PRIVATE_TO_JSVAL(privateData));

    /* Flag the error report passed in to indicate an exception was raised. */
    reportp->flags |= JSREPORT_EXCEPTION;

out:
    cx->creatingException = JS_FALSE;
    return ok;
}
#endif /* JS_HAS_ERROR_EXCEPTIONS */

#if JS_HAS_EXCEPTIONS

JSBool
js_ReportUncaughtException(JSContext *cx)
{
    JSObject *exnObject;
    JSString *str;
    jsval exn;
    JSErrorReport *reportp;
    const char *bytes;

    if (!JS_IsExceptionPending(cx))
        return JS_TRUE;

    if (!JS_GetPendingException(cx, &exn))
        return JS_FALSE;

    /*
     * Because js_ValueToString below could error and an exception object
     * could become unrooted, we must root exnObject.
     */
    if (JSVAL_IS_PRIMITIVE(exn)) {
        exnObject = NULL;
    } else {
        exnObject = JSVAL_TO_OBJECT(exn);
        if (!js_AddRoot(cx, &exnObject, "exn.report.root"))
            return JS_FALSE;
    }

#if JS_HAS_ERROR_EXCEPTIONS
    reportp = js_ErrorFromException(cx, exn);
#else
    reportp = NULL;
#endif

    str = js_ValueToString(cx, exn);
    bytes = str ? js_GetStringBytes(str) : "null";

    if (reportp == NULL) {
        /*
         * XXXmccabe todo: Instead of doing this, synthesize an error report
         * struct that includes the filename, lineno where the exception was
         * originally thrown.
         */
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                             JSMSG_UNCAUGHT_EXCEPTION, bytes);
    } else {
        /* Flag the error as an exception. */
        reportp->flags |= JSREPORT_EXCEPTION;
        js_ReportErrorAgain(cx, bytes, reportp);
    }

    if (exnObject != NULL)
        js_RemoveRoot(cx->runtime, &exnObject);
    JS_ClearPendingException(cx);
    return JS_TRUE;
}

#endif /* JS_HAS_EXCEPTIONS */