JS_SetWatchPoint(JSContext *cx, JSObject *obj, jsval id,
JSWatchPointHandler handler, void *closure)
{
JSAtom *atom;
jsid propid;
JSObject *pobj;
JSScopeProperty *sprop;
JSRuntime *rt;
JSWatchPoint *wp;
JSPropertyOp watcher;
if (!OBJ_IS_NATIVE(obj)) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_CANT_WATCH,
OBJ_GET_CLASS(cx, obj)->name);
return JS_FALSE;
}
if (JSVAL_IS_INT(id)) {
propid = (jsid)id;
atom = NULL;
} else {
atom = js_ValueToStringAtom(cx, id);
if (!atom)
return JS_FALSE;
propid = (jsid)atom;
}
if (!js_LookupProperty(cx, obj, propid, &pobj, (JSProperty **)&sprop))
return JS_FALSE;
rt = cx->runtime;
if (!sprop) {
/* Check for a deleted symbol watchpoint, which holds its property. */
sprop = js_FindWatchPoint(rt, OBJ_SCOPE(obj), propid);
if (!sprop) {
/* Make a new property in obj so we can watch for the first set. */
if (!js_DefineProperty(cx, obj, propid, JSVAL_VOID,
NULL, NULL, JSPROP_ENUMERATE,
(JSProperty **)&sprop)) {
sprop = NULL;
}
}
} else if (pobj != obj) {
/* Clone the prototype property so we can watch the right object. */
jsval value;
JSPropertyOp getter, setter;
uintN attrs;
if (OBJ_IS_NATIVE(pobj)) {
value = SPROP_HAS_VALID_SLOT(sprop, OBJ_SCOPE(pobj))
? LOCKED_OBJ_GET_SLOT(pobj, sprop->slot)
: JSVAL_VOID;
getter = sprop->getter;
setter = sprop->setter;
attrs = sprop->attrs;
} else {
if (!OBJ_GET_PROPERTY(cx, pobj, id, &value)) {
OBJ_DROP_PROPERTY(cx, pobj, (JSProperty *)sprop);
return JS_FALSE;
}
getter = setter = JS_PropertyStub;
attrs = JSPROP_ENUMERATE;
}
OBJ_DROP_PROPERTY(cx, pobj, (JSProperty *)sprop);
if (!js_DefineProperty(cx, obj, propid, value, getter, setter, attrs,
(JSProperty **)&sprop)) {
sprop = NULL;
}
}
if (!sprop)
return JS_FALSE;
wp = FindWatchPoint(rt, OBJ_SCOPE(obj), propid);
if (!wp) {
watcher = js_WrapWatchedSetter(cx, propid, sprop->attrs, sprop->setter);
if (!watcher)
return JS_FALSE;
wp = (JSWatchPoint *) JS_malloc(cx, sizeof *wp);
if (!wp)
return JS_FALSE;
wp->handler = NULL;
wp->closure = NULL;
if (!js_AddRoot(cx, &wp->closure, "wp->closure")) {
JS_free(cx, wp);
return JS_FALSE;
}
JS_APPEND_LINK(&wp->links, &rt->watchPointList);
wp->object = obj;
wp->sprop = sprop;
JS_ASSERT(sprop->setter != js_watch_set);
wp->setter = sprop->setter;
wp->nrefs = 1;
sprop = js_ChangeNativePropertyAttrs(cx, obj, sprop, 0, sprop->attrs,
sprop->getter, watcher);
if (!sprop)
return DropWatchPoint(cx, wp);
}
wp->handler = handler;
wp->closure = closure;
OBJ_DROP_PROPERTY(cx, obj, (JSProperty *)sprop);
return JS_TRUE;
}
static JSBool
obj_watch(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
JSFunction *fun;
jsval userid, symid, propid, value;
JSAtom *atom;
JSRuntime *rt;
JSBool ok;
JSProperty *prop;
JSPropertyOp getter, setter;
JSClass *clasp;
fun = JS_ValueToFunction(cx, argv[1]);
if (!fun)
return JS_FALSE;
argv[1] = OBJECT_TO_JSVAL(fun->object);
/*
* Lock the world while we look in obj. Be sure to return via goto out
* on error, so we unlock.
*/
rt = cx->runtime;
JS_LOCK_RUNTIME(rt);
/* Compute the unique int/atom symbol id needed by js_LookupProperty. */
userid = argv[0];
if (JSVAL_IS_INT(userid)) {
symid = userid;
atom = NULL;
} else {
atom = js_ValueToStringAtom(cx, userid);
if (!atom) {
ok = JS_FALSE;
goto out;
}
symid = (jsval)atom;
}
ok = js_LookupProperty(cx, obj, symid, &obj, &prop);
if (atom)
js_DropAtom(cx, atom);
if (!ok)
goto out;
/* Set propid from the property, in case it has a tinyid. */
if (prop) {
propid = prop->id;
getter = prop->getter;
setter = prop->setter;
value = prop->object->slots[prop->slot];
} else {
propid = userid;
clasp = obj->map->clasp;
getter = clasp->getProperty;
setter = clasp->setProperty;
value = JSVAL_VOID;
}
/*
* Security policy is implemented in getters and setters, so we have to
* call get and set here to let the JS API client check for a watchpoint
* that crosses a trust boundary.
* XXX assumes get and set are idempotent, should use a clasp->watch hook
*/
ok = getter(cx, obj, propid, &value) && setter(cx, obj, propid, &value);
if (!ok)
goto out;
/* Finally, call into jsdbgapi.c to set the watchpoint on userid. */
ok = JS_SetWatchPoint(cx, obj, userid, obj_watch_handler, fun->object);
out:
JS_UNLOCK_RUNTIME(rt);
return ok;
}
