The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/js/src/tests/ecma_5/extensions/watchpoint-deletes-JSPropertyOp-setter.js	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,56 @@
     1.4 +/*
     1.5 + * Any copyright is dedicated to the Public Domain.
     1.6 + * http://creativecommons.org/licenses/publicdomain/
     1.7 + */
     1.8 +
     1.9 +function make_watcher(name) {
    1.10 +    return function (id, oldv, newv) {
    1.11 +        print("watched " + name + "[0]");
    1.12 +    };
    1.13 +}
    1.14 +
    1.15 +var o, p;
    1.16 +function f(flag) {
    1.17 +    if (flag) {
    1.18 +        o = arguments;
    1.19 +    } else {
    1.20 +        p = arguments;
    1.21 +        o.watch(0, make_watcher('o'));
    1.22 +        p.watch(0, make_watcher('p'));
    1.23 +
    1.24 +        /*
    1.25 +         * Previously, the watchpoint implementation actually substituted its magic setter
    1.26 +         * functions for the setters of shared shapes, and then 1) carefully ignored calls
    1.27 +         * to its magic setter from unrelated objects, and 2) avoided restoring the
    1.28 +         * original setter until all watchpoints on that shape had been removed.
    1.29 +         * 
    1.30 +         * However, when the watchpoint code began using JSObject::changeProperty and
    1.31 +         * js_ChangeNativePropertyAttrs to change shapes' setters, the shape tree code
    1.32 +         * became conscious of the presence of watchpoints, and shared shapes between
    1.33 +         * objects only when their watchpoint nature coincided. Clearing the magic setter
    1.34 +         * from one object's shape would not affect other objects, because the
    1.35 +         * watchpointed and non-watchpointed shapes were distinct if they were shared.
    1.36 +         * 
    1.37 +         * Thus, the first unwatch call must go ahead and fix p's shape, even though a
    1.38 +         * watchpoint exists on the same shape in o. o's watchpoint's presence shouldn't
    1.39 +         * cause 'unwatch' to leave p's magic setter in place.
    1.40 +         */
    1.41 +
    1.42 +        /* DropWatchPointAndUnlock would see o's watchpoint, and not change p's property. */
    1.43 +        p.unwatch(0);
    1.44 +
    1.45 +        /* DropWatchPointAndUnlock would fix o's property, but not p's; p's setter would be gone. */
    1.46 +        o.unwatch(0);
    1.47 +
    1.48 +        /* This would fail to invoke the arguments object's setter. */
    1.49 +        p[0] = 4;
    1.50 +
    1.51 +        /* And the formal parameter would not get updated. */
    1.52 +        assertEq(flag, 4);
    1.53 +    }
    1.54 +}
    1.55 +
    1.56 +f(true);
    1.57 +f(false);
    1.58 +
    1.59 +reportCompare(true, true);