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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* Finalization registry GC implementation.
*/
#include "builtin/FinalizationRegistryObject.h"
#include "gc/GCRuntime.h"
#include "gc/Zone.h"
#include "vm/JSContext.h"
#include "gc/PrivateIterators-inl.h"
#include "vm/JSObject-inl.h"
using namespace js;
using namespace js::gc;
bool GCRuntime::addFinalizationRegistry(JSContext* cx,
FinalizationRegistryObject* registry) {
if (!cx->zone()->finalizationRegistries().put(registry)) {
ReportOutOfMemory(cx);
return false;
}
return true;
}
bool GCRuntime::registerWithFinalizationRegistry(JSContext* cx,
HandleObject target,
HandleObject record) {
MOZ_ASSERT(!IsCrossCompartmentWrapper(target));
MOZ_ASSERT(
UncheckedUnwrapWithoutExpose(record)->is<FinalizationRecordObject>());
MOZ_ASSERT(target->compartment() == record->compartment());
auto& map = target->zone()->finalizationRecordMap();
auto ptr = map.lookupForAdd(target);
if (!ptr) {
if (!map.add(ptr, target, FinalizationRecordVector(target->zone()))) {
ReportOutOfMemory(cx);
return false;
}
}
if (!ptr->value().append(record)) {
ReportOutOfMemory(cx);
return false;
}
return true;
}
void GCRuntime::markFinalizationRegistryRoots(JSTracer* trc) {
// All finalization records stored in the zone maps are marked as roots.
// Records can be removed from these maps during sweeping in which case they
// die in the next collection.
for (GCZonesIter zone(this); !zone.done(); zone.next()) {
Zone::FinalizationRecordMap& map = zone->finalizationRecordMap();
for (Zone::FinalizationRecordMap::Enum e(map); !e.empty(); e.popFront()) {
e.front().value().trace(trc);
}
}
}
static FinalizationRecordObject* UnwrapFinalizationRecord(JSObject* obj) {
obj = UncheckedUnwrapWithoutExpose(obj);
if (!obj->is<FinalizationRecordObject>()) {
MOZ_ASSERT(JS_IsDeadWrapper(obj));
// CCWs between the compartments have been nuked. The
// FinalizationRegistry's callback doesn't run in this case.
return nullptr;
}
return &obj->as<FinalizationRecordObject>();
}
void GCRuntime::sweepFinalizationRegistries(Zone* zone) {
// Sweep finalization registry data and queue finalization records for cleanup
// for any entries whose target is dying and remove them from the map.
Zone::FinalizationRegistrySet& set = zone->finalizationRegistries();
for (Zone::FinalizationRegistrySet::Enum e(set); !e.empty(); e.popFront()) {
if (IsAboutToBeFinalized(&e.mutableFront())) {
e.front()->as<FinalizationRegistryObject>().queue()->setHasRegistry(
false);
e.removeFront();
} else {
e.front()->as<FinalizationRegistryObject>().sweep();
}
}
Zone::FinalizationRecordMap& map = zone->finalizationRecordMap();
for (Zone::FinalizationRecordMap::Enum e(map); !e.empty(); e.popFront()) {
FinalizationRecordVector& records = e.front().value();
// Update any pointers moved by the GC.
records.sweep();
// Sweep finalization records and remove records for:
records.eraseIf([](JSObject* obj) {
FinalizationRecordObject* record = UnwrapFinalizationRecord(obj);
return !record || // Nuked CCW to record.
!record->isActive() || // Unregistered record.
!record->queue()->hasRegistry(); // Dead finalization registry.
});
// Queue finalization records for targets that are dying.
if (IsAboutToBeFinalized(&e.front().mutableKey())) {
for (JSObject* obj : records) {
FinalizationRecordObject* record = UnwrapFinalizationRecord(obj);
FinalizationQueueObject* queue = record->queue();
queue->queueRecordToBeCleanedUp(record);
queueFinalizationRegistryForCleanup(queue);
}
e.removeFront();
}
}
}
void GCRuntime::queueFinalizationRegistryForCleanup(
FinalizationQueueObject* queue) {
// Prod the embedding to call us back later to run the finalization callbacks,
// if necessary.
if (queue->isQueuedForCleanup()) {
return;
}
// Derive the incumbent global by unwrapping the incumbent global object and
// then getting its global.
JSObject* object = UncheckedUnwrapWithoutExpose(queue->incumbentObject());
MOZ_ASSERT(object);
GlobalObject* incumbentGlobal = &object->nonCCWGlobal();
callHostCleanupFinalizationRegistryCallback(queue->doCleanupFunction(),
incumbentGlobal);
queue->setQueuedForCleanup(true);
}