michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "jswatchpoint.h"
michael@0: 
michael@0: #include "jsatom.h"
michael@0: #include "jscompartment.h"
michael@0: #include "jsfriendapi.h"
michael@0: 
michael@0: #include "gc/Marking.h"
michael@0: 
michael@0: #include "jsgcinlines.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace js::gc;
michael@0: 
michael@0: inline HashNumber
michael@0: DefaultHasher<WatchKey>::hash(const Lookup &key)
michael@0: {
michael@0:     return DefaultHasher<JSObject *>::hash(key.object.get()) ^ HashId(key.id.get());
michael@0: }
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: class AutoEntryHolder {
michael@0:     typedef WatchpointMap::Map Map;
michael@0:     Map &map;
michael@0:     Map::Ptr p;
michael@0:     uint32_t gen;
michael@0:     RootedObject obj;
michael@0:     RootedId id;
michael@0: 
michael@0:   public:
michael@0:     AutoEntryHolder(JSContext *cx, Map &map, Map::Ptr p)
michael@0:       : map(map), p(p), gen(map.generation()), obj(cx, p->key().object), id(cx, p->key().id)
michael@0:     {
michael@0:         JS_ASSERT(!p->value().held);
michael@0:         p->value().held = true;
michael@0:     }
michael@0: 
michael@0:     ~AutoEntryHolder() {
michael@0:         if (gen != map.generation())
michael@0:             p = map.lookup(WatchKey(obj, id));
michael@0:         if (p)
michael@0:             p->value().held = false;
michael@0:     }
michael@0: };
michael@0: 
michael@0: } /* anonymous namespace */
michael@0: 
michael@0: bool
michael@0: WatchpointMap::init()
michael@0: {
michael@0:     return map.init();
michael@0: }
michael@0: 
michael@0: bool
michael@0: WatchpointMap::watch(JSContext *cx, HandleObject obj, HandleId id,
michael@0:                      JSWatchPointHandler handler, HandleObject closure)
michael@0: {
michael@0:     JS_ASSERT(JSID_IS_STRING(id) || JSID_IS_INT(id));
michael@0: 
michael@0:     if (!obj->setWatched(cx))
michael@0:         return false;
michael@0: 
michael@0:     Watchpoint w(handler, closure, false);
michael@0:     if (!map.put(WatchKey(obj, id), w)) {
michael@0:         js_ReportOutOfMemory(cx);
michael@0:         return false;
michael@0:     }
michael@0:     /*
michael@0:      * For generational GC, we don't need to post-barrier writes to the
michael@0:      * hashtable here because we mark all watchpoints as part of root marking in
michael@0:      * markAll().
michael@0:      */
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::unwatch(JSObject *obj, jsid id,
michael@0:                        JSWatchPointHandler *handlerp, JSObject **closurep)
michael@0: {
michael@0:     if (Map::Ptr p = map.lookup(WatchKey(obj, id))) {
michael@0:         if (handlerp)
michael@0:             *handlerp = p->value().handler;
michael@0:         if (closurep) {
michael@0:             // Read barrier to prevent an incorrectly gray closure from escaping the
michael@0:             // watchpoint. See the comment before UnmarkGrayChildren in gc/Marking.cpp
michael@0:             JS::ExposeGCThingToActiveJS(p->value().closure, JSTRACE_OBJECT);
michael@0:             *closurep = p->value().closure;
michael@0:         }
michael@0:         map.remove(p);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::unwatchObject(JSObject *obj)
michael@0: {
michael@0:     for (Map::Enum e(map); !e.empty(); e.popFront()) {
michael@0:         Map::Entry &entry = e.front();
michael@0:         if (entry.key().object == obj)
michael@0:             e.removeFront();
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::clear()
michael@0: {
michael@0:     map.clear();
michael@0: }
michael@0: 
michael@0: bool
michael@0: WatchpointMap::triggerWatchpoint(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp)
michael@0: {
michael@0:     Map::Ptr p = map.lookup(WatchKey(obj, id));
michael@0:     if (!p || p->value().held)
michael@0:         return true;
michael@0: 
michael@0:     AutoEntryHolder holder(cx, map, p);
michael@0: 
michael@0:     /* Copy the entry, since GC would invalidate p. */
michael@0:     JSWatchPointHandler handler = p->value().handler;
michael@0:     RootedObject closure(cx, p->value().closure);
michael@0: 
michael@0:     /* Determine the property's old value. */
michael@0:     Value old;
michael@0:     old.setUndefined();
michael@0:     if (obj->isNative()) {
michael@0:         if (Shape *shape = obj->nativeLookup(cx, id)) {
michael@0:             if (shape->hasSlot())
michael@0:                 old = obj->nativeGetSlot(shape->slot());
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // Read barrier to prevent an incorrectly gray closure from escaping the
michael@0:     // watchpoint. See the comment before UnmarkGrayChildren in gc/Marking.cpp
michael@0:     JS::ExposeGCThingToActiveJS(closure, JSTRACE_OBJECT);
michael@0: 
michael@0:     /* Call the handler. */
michael@0:     return handler(cx, obj, id, old, vp.address(), closure);
michael@0: }
michael@0: 
michael@0: bool
michael@0: WatchpointMap::markCompartmentIteratively(JSCompartment *c, JSTracer *trc)
michael@0: {
michael@0:     if (!c->watchpointMap)
michael@0:         return false;
michael@0:     return c->watchpointMap->markIteratively(trc);
michael@0: }
michael@0: 
michael@0: bool
michael@0: WatchpointMap::markIteratively(JSTracer *trc)
michael@0: {
michael@0:     bool marked = false;
michael@0:     for (Map::Enum e(map); !e.empty(); e.popFront()) {
michael@0:         Map::Entry &entry = e.front();
michael@0:         JSObject *priorKeyObj = entry.key().object;
michael@0:         jsid priorKeyId(entry.key().id.get());
michael@0:         bool objectIsLive =
michael@0:             IsObjectMarked(const_cast<EncapsulatedPtrObject *>(&entry.key().object));
michael@0:         if (objectIsLive || entry.value().held) {
michael@0:             if (!objectIsLive) {
michael@0:                 MarkObject(trc, const_cast<EncapsulatedPtrObject *>(&entry.key().object),
michael@0:                            "held Watchpoint object");
michael@0:                 marked = true;
michael@0:             }
michael@0: 
michael@0:             JS_ASSERT(JSID_IS_STRING(priorKeyId) || JSID_IS_INT(priorKeyId));
michael@0:             MarkId(trc, const_cast<EncapsulatedId *>(&entry.key().id), "WatchKey::id");
michael@0: 
michael@0:             if (entry.value().closure && !IsObjectMarked(&entry.value().closure)) {
michael@0:                 MarkObject(trc, &entry.value().closure, "Watchpoint::closure");
michael@0:                 marked = true;
michael@0:             }
michael@0: 
michael@0:             /* We will sweep this entry in sweepAll if !objectIsLive. */
michael@0:             if (priorKeyObj != entry.key().object || priorKeyId != entry.key().id)
michael@0:                 e.rekeyFront(WatchKey(entry.key().object, entry.key().id));
michael@0:         }
michael@0:     }
michael@0:     return marked;
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::markAll(JSTracer *trc)
michael@0: {
michael@0:     for (Map::Enum e(map); !e.empty(); e.popFront()) {
michael@0:         Map::Entry &entry = e.front();
michael@0:         WatchKey key = entry.key();
michael@0:         WatchKey prior = key;
michael@0:         JS_ASSERT(JSID_IS_STRING(prior.id) || JSID_IS_INT(prior.id));
michael@0: 
michael@0:         MarkObject(trc, const_cast<EncapsulatedPtrObject *>(&key.object),
michael@0:                    "held Watchpoint object");
michael@0:         MarkId(trc, const_cast<EncapsulatedId *>(&key.id), "WatchKey::id");
michael@0:         MarkObject(trc, &entry.value().closure, "Watchpoint::closure");
michael@0: 
michael@0:         if (prior.object != key.object || prior.id != key.id)
michael@0:             e.rekeyFront(key);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::sweepAll(JSRuntime *rt)
michael@0: {
michael@0:     for (GCCompartmentsIter c(rt); !c.done(); c.next()) {
michael@0:         if (WatchpointMap *wpmap = c->watchpointMap)
michael@0:             wpmap->sweep();
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::sweep()
michael@0: {
michael@0:     for (Map::Enum e(map); !e.empty(); e.popFront()) {
michael@0:         Map::Entry &entry = e.front();
michael@0:         JSObject *obj(entry.key().object);
michael@0:         if (IsObjectAboutToBeFinalized(&obj)) {
michael@0:             JS_ASSERT(!entry.value().held);
michael@0:             e.removeFront();
michael@0:         } else if (obj != entry.key().object) {
michael@0:             e.rekeyFront(WatchKey(obj, entry.key().id));
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::traceAll(WeakMapTracer *trc)
michael@0: {
michael@0:     JSRuntime *rt = trc->runtime;
michael@0:     for (CompartmentsIter comp(rt, SkipAtoms); !comp.done(); comp.next()) {
michael@0:         if (WatchpointMap *wpmap = comp->watchpointMap)
michael@0:             wpmap->trace(trc);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WatchpointMap::trace(WeakMapTracer *trc)
michael@0: {
michael@0:     for (Map::Range r = map.all(); !r.empty(); r.popFront()) {
michael@0:         Map::Entry &entry = r.front();
michael@0:         trc->callback(trc, nullptr,
michael@0:                       entry.key().object.get(), JSTRACE_OBJECT,
michael@0:                       entry.value().closure.get(), JSTRACE_OBJECT);
michael@0:     }
michael@0: }