https://github.com/mozilla/gecko-dev
Tip revision: 313ee0f00756c8739b2d28ae0f5d620c008239e0 authored by Ryan VanderMeulen on 29 July 2015, 14:14:54 UTC
Added tag B2G_2_0M_END for changeset 4e82c466cac4 on a CLOSED TREE
Added tag B2G_2_0M_END for changeset 4e82c466cac4 on a CLOSED TREE
Tip revision: 313ee0f
jsweakmap.cpp
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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/. */
#include "jsweakmap.h"
#include <string.h>
#include "jsapi.h"
#include "jscntxt.h"
#include "jsfriendapi.h"
#include "jsobj.h"
#include "jswrapper.h"
#include "vm/GlobalObject.h"
#include "vm/WeakMapObject.h"
#include "jsobjinlines.h"
using namespace js;
using namespace js::gc;
WeakMapBase::WeakMapBase(JSObject* memOf, JSCompartment* c)
: memberOf(memOf),
compartment(c),
next(WeakMapNotInList),
marked(false)
{
JS_ASSERT_IF(memberOf, memberOf->compartment() == c);
}
WeakMapBase::~WeakMapBase()
{
JS_ASSERT(!isInList());
}
void
WeakMapBase::trace(JSTracer* tracer)
{
JS_ASSERT(isInList());
if (IS_GC_MARKING_TRACER(tracer)) {
// We don't trace any of the WeakMap entries at this time, just record
// record the fact that the WeakMap has been marked. Enties are marked
// in the iterative marking phase by markAllIteratively(), which happens
// when many keys as possible have been marked already.
JS_ASSERT(tracer->eagerlyTraceWeakMaps() == DoNotTraceWeakMaps);
marked = true;
} else {
// If we're not actually doing garbage collection, the keys won't be marked
// nicely as needed by the true ephemeral marking algorithm --- custom tracers
// such as the cycle collector must use their own means for cycle detection.
// So here we do a conservative approximation: pretend all keys are live.
if (tracer->eagerlyTraceWeakMaps() == DoNotTraceWeakMaps)
return;
nonMarkingTraceValues(tracer);
if (tracer->eagerlyTraceWeakMaps() == TraceWeakMapKeysValues)
nonMarkingTraceKeys(tracer);
}
}
void
WeakMapBase::unmarkCompartment(JSCompartment* c)
{
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next)
m->marked = false;
}
bool
WeakMapBase::markCompartmentIteratively(JSCompartment* c, JSTracer* tracer)
{
bool markedAny = false;
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next) {
if (m->marked && m->markIteratively(tracer))
markedAny = true;
}
return markedAny;
}
bool
WeakMapBase::findZoneEdgesForCompartment(JSCompartment* c)
{
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next) {
if (!m->findZoneEdges())
return false;
}
return true;
}
void
WeakMapBase::sweepCompartment(JSCompartment* c)
{
WeakMapBase** tailPtr = &c->gcWeakMapList;
for (WeakMapBase* m = c->gcWeakMapList, *next; m; m = next) {
next = m->next;
if (m->marked) {
m->sweep();
*tailPtr = m;
tailPtr = &m->next;
} else {
/* Destroy the hash map now to catch any use after this point. */
m->finish();
m->next = WeakMapNotInList;
}
}
*tailPtr = nullptr;
#ifdef DEBUG
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next)
JS_ASSERT(m->isInList() && m->marked);
#endif
}
void
WeakMapBase::traceAllMappings(WeakMapTracer* tracer)
{
JSRuntime* rt = tracer->runtime;
for (CompartmentsIter c(rt, SkipAtoms); !c.done(); c.next()) {
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next)
m->traceMappings(tracer);
}
}
bool
WeakMapBase::saveCompartmentMarkedWeakMaps(JSCompartment* c, WeakMapSet& markedWeakMaps)
{
for (WeakMapBase* m = c->gcWeakMapList; m; m = m->next) {
if (m->marked && !markedWeakMaps.put(m))
return false;
}
return true;
}
void
WeakMapBase::restoreCompartmentMarkedWeakMaps(WeakMapSet& markedWeakMaps)
{
for (WeakMapSet::Range r = markedWeakMaps.all(); !r.empty(); r.popFront()) {
WeakMapBase* map = r.front();
JS_ASSERT(map->compartment->zone()->isGCMarking());
JS_ASSERT(!map->marked);
map->marked = true;
}
}
void
WeakMapBase::removeWeakMapFromList(WeakMapBase* weakmap)
{
JSCompartment* c = weakmap->compartment;
for (WeakMapBase** p = &c->gcWeakMapList; *p; p = &(*p)->next) {
if (*p == weakmap) {
*p = (*p)->next;
weakmap->next = WeakMapNotInList;
break;
}
}
}
bool
ObjectValueMap::findZoneEdges()
{
/*
* For unmarked weakmap keys with delegates in a different zone, add a zone
* edge to ensure that the delegate zone does finish marking after the key
* zone.
*/
JS::AutoSuppressGCAnalysis nogc;
Zone* mapZone = compartment->zone();
for (Range r = all(); !r.empty(); r.popFront()) {
JSObject* key = r.front().key();
if (key->isMarked(BLACK) && !key->isMarked(GRAY))
continue;
JSWeakmapKeyDelegateOp op = key->getClass()->ext.weakmapKeyDelegateOp;
if (!op)
continue;
JSObject* delegate = op(key);
if (!delegate)
continue;
Zone* delegateZone = delegate->zone();
if (delegateZone == mapZone)
continue;
if (!delegateZone->gcZoneGroupEdges.put(key->zone()))
return false;
}
return true;
}
static JSObject*
GetKeyArg(JSContext* cx, CallArgs& args)
{
if (args[0].isPrimitive()) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_NOT_NONNULL_OBJECT);
return nullptr;
}
return &args[0].toObject();
}
MOZ_ALWAYS_INLINE bool
IsWeakMap(HandleValue v)
{
return v.isObject() && v.toObject().is<WeakMapObject>();
}
MOZ_ALWAYS_INLINE bool
WeakMap_has_impl(JSContext* cx, CallArgs args)
{
JS_ASSERT(IsWeakMap(args.thisv()));
if (args.length() < 1) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_MORE_ARGS_NEEDED,
"WeakMap.has", "0", "s");
return false;
}
JSObject* key = GetKeyArg(cx, args);
if (!key)
return false;
if (ObjectValueMap* map = args.thisv().toObject().as<WeakMapObject>().getMap()) {
if (map->has(key)) {
args.rval().setBoolean(true);
return true;
}
}
args.rval().setBoolean(false);
return true;
}
static bool
WeakMap_has(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsWeakMap, WeakMap_has_impl>(cx, args);
}
MOZ_ALWAYS_INLINE bool
WeakMap_clear_impl(JSContext* cx, CallArgs args)
{
JS_ASSERT(IsWeakMap(args.thisv()));
// We can't js_delete the weakmap because the data gathered during GC is
// used by the Cycle Collector.
if (ObjectValueMap* map = args.thisv().toObject().as<WeakMapObject>().getMap())
map->clear();
args.rval().setUndefined();
return true;
}
static bool
WeakMap_clear(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsWeakMap, WeakMap_clear_impl>(cx, args);
}
MOZ_ALWAYS_INLINE bool
WeakMap_get_impl(JSContext* cx, CallArgs args)
{
JS_ASSERT(IsWeakMap(args.thisv()));
if (args.length() < 1) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_MORE_ARGS_NEEDED,
"WeakMap.get", "0", "s");
return false;
}
JSObject* key = GetKeyArg(cx, args);
if (!key)
return false;
if (ObjectValueMap* map = args.thisv().toObject().as<WeakMapObject>().getMap()) {
if (ObjectValueMap::Ptr ptr = map->lookup(key)) {
// Read barrier to prevent an incorrectly gray value from escaping the
// weak map. See the comment before UnmarkGrayChildren in gc/Marking.cpp
ExposeValueToActiveJS(ptr->value().get());
args.rval().set(ptr->value());
return true;
}
}
args.rval().set((args.length() > 1) ? args[1] : UndefinedValue());
return true;
}
static bool
WeakMap_get(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsWeakMap, WeakMap_get_impl>(cx, args);
}
MOZ_ALWAYS_INLINE bool
WeakMap_delete_impl(JSContext* cx, CallArgs args)
{
JS_ASSERT(IsWeakMap(args.thisv()));
if (args.length() < 1) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_MORE_ARGS_NEEDED,
"WeakMap.delete", "0", "s");
return false;
}
JSObject* key = GetKeyArg(cx, args);
if (!key)
return false;
if (ObjectValueMap* map = args.thisv().toObject().as<WeakMapObject>().getMap()) {
if (ObjectValueMap::Ptr ptr = map->lookup(key)) {
map->remove(ptr);
args.rval().setBoolean(true);
return true;
}
}
args.rval().setBoolean(false);
return true;
}
static bool
WeakMap_delete(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsWeakMap, WeakMap_delete_impl>(cx, args);
}
static bool
TryPreserveReflector(JSContext* cx, HandleObject obj)
{
if (obj->getClass()->ext.isWrappedNative ||
(obj->getClass()->flags & JSCLASS_IS_DOMJSCLASS) ||
(obj->is<ProxyObject>() &&
obj->as<ProxyObject>().handler()->family() == GetDOMProxyHandlerFamily()))
{
JS_ASSERT(cx->runtime()->preserveWrapperCallback);
if (!cx->runtime()->preserveWrapperCallback(cx, obj)) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_BAD_WEAKMAP_KEY);
return false;
}
}
return true;
}
static inline void
WeakMapPostWriteBarrier(JSRuntime* rt, ObjectValueMap* weakMap, JSObject* key)
{
#ifdef JSGC_GENERATIONAL
/*
* Strip the barriers from the type before inserting into the store buffer.
* This will automatically ensure that barriers do not fire during GC.
*
* Some compilers complain about instantiating the WeakMap class for
* unbarriered type arguments, so we cast to a HashMap instead. Because of
* WeakMap's multiple inheritace, We need to do this in two stages, first to
* the HashMap base class and then to the unbarriered version.
*/
ObjectValueMap::Base* baseHashMap = static_cast<ObjectValueMap::Base*>(weakMap);
typedef HashMap<JSObject*, Value> UnbarrieredMap;
UnbarrieredMap* unbarrieredMap = reinterpret_cast<UnbarrieredMap*>(baseHashMap);
typedef HashKeyRef<UnbarrieredMap, JSObject*> Ref;
if (key && IsInsideNursery(key))
rt->gc.storeBuffer.putGeneric(Ref((unbarrieredMap), key));
#endif
}
MOZ_ALWAYS_INLINE bool
SetWeakMapEntryInternal(JSContext* cx, Handle<WeakMapObject*> mapObj,
HandleObject key, HandleValue value)
{
ObjectValueMap* map = mapObj->getMap();
if (!map) {
map = cx->new_<ObjectValueMap>(cx, mapObj.get());
if (!map)
return false;
if (!map->init()) {
js_delete(map);
JS_ReportOutOfMemory(cx);
return false;
}
mapObj->setPrivate(map);
}
// Preserve wrapped native keys to prevent wrapper optimization.
if (!TryPreserveReflector(cx, key))
return false;
if (JSWeakmapKeyDelegateOp op = key->getClass()->ext.weakmapKeyDelegateOp) {
RootedObject delegate(cx, op(key));
if (delegate && !TryPreserveReflector(cx, delegate))
return false;
}
JS_ASSERT(key->compartment() == mapObj->compartment());
JS_ASSERT_IF(value.isObject(), value.toObject().compartment() == mapObj->compartment());
if (!map->put(key, value)) {
JS_ReportOutOfMemory(cx);
return false;
}
WeakMapPostWriteBarrier(cx->runtime(), map, key.get());
return true;
}
MOZ_ALWAYS_INLINE bool
WeakMap_set_impl(JSContext* cx, CallArgs args)
{
JS_ASSERT(IsWeakMap(args.thisv()));
if (args.length() < 1) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_MORE_ARGS_NEEDED,
"WeakMap.set", "0", "s");
return false;
}
RootedObject key(cx, GetKeyArg(cx, args));
if (!key)
return false;
RootedValue value(cx, (args.length() > 1) ? args[1] : UndefinedValue());
Rooted<JSObject*> thisObj(cx, &args.thisv().toObject());
Rooted<WeakMapObject*> map(cx, &thisObj->as<WeakMapObject>());
args.rval().setUndefined();
return SetWeakMapEntryInternal(cx, map, key, value);
}
static bool
WeakMap_set(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsWeakMap, WeakMap_set_impl>(cx, args);
}
JS_FRIEND_API(bool)
JS_NondeterministicGetWeakMapKeys(JSContext* cx, HandleObject objArg, MutableHandleObject ret)
{
RootedObject obj(cx, objArg);
obj = UncheckedUnwrap(obj);
if (!obj || !obj->is<WeakMapObject>()) {
ret.set(nullptr);
return true;
}
RootedObject arr(cx, NewDenseEmptyArray(cx));
if (!arr)
return false;
ObjectValueMap* map = obj->as<WeakMapObject>().getMap();
if (map) {
// Prevent GC from mutating the weakmap while iterating.
AutoSuppressGC suppress(cx);
for (ObjectValueMap::Base::Range r = map->all(); !r.empty(); r.popFront()) {
RootedObject key(cx, r.front().key());
if (!cx->compartment()->wrap(cx, &key))
return false;
if (!NewbornArrayPush(cx, arr, ObjectValue(*key)))
return false;
}
}
ret.set(arr);
return true;
}
static void
WeakMap_mark(JSTracer* trc, JSObject* obj)
{
if (ObjectValueMap* map = obj->as<WeakMapObject>().getMap())
map->trace(trc);
}
static void
WeakMap_finalize(FreeOp* fop, JSObject* obj)
{
if (ObjectValueMap* map = obj->as<WeakMapObject>().getMap()) {
#ifdef DEBUG
map->~ObjectValueMap();
memset(static_cast<void*>(map), 0xdc, sizeof(*map));
fop->free_(map);
#else
fop->delete_(map);
#endif
}
}
JS_PUBLIC_API(JSObject*)
JS::NewWeakMapObject(JSContext* cx)
{
return NewBuiltinClassInstance(cx, &WeakMapObject::class_);
}
JS_PUBLIC_API(bool)
JS::IsWeakMapObject(JSObject* obj)
{
return obj->is<WeakMapObject>();
}
JS_PUBLIC_API(bool)
JS::GetWeakMapEntry(JSContext* cx, HandleObject mapObj, HandleObject key,
MutableHandleValue rval)
{
CHECK_REQUEST(cx);
assertSameCompartment(cx, key);
rval.setUndefined();
ObjectValueMap* map = mapObj->as<WeakMapObject>().getMap();
if (!map)
return true;
if (ObjectValueMap::Ptr ptr = map->lookup(key)) {
// Read barrier to prevent an incorrectly gray value from escaping the
// weak map. See the comment before UnmarkGrayChildren in gc/Marking.cpp
ExposeValueToActiveJS(ptr->value().get());
rval.set(ptr->value());
}
return true;
}
JS_PUBLIC_API(bool)
JS::SetWeakMapEntry(JSContext* cx, HandleObject mapObj, HandleObject key,
HandleValue val)
{
CHECK_REQUEST(cx);
assertSameCompartment(cx, key, val);
Rooted<WeakMapObject*> rootedMap(cx, &mapObj->as<WeakMapObject>());
return SetWeakMapEntryInternal(cx, rootedMap, key, val);
}
static bool
WeakMap_construct(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
JSObject* obj = NewBuiltinClassInstance(cx, &WeakMapObject::class_);
if (!obj)
return false;
args.rval().setObject(*obj);
return true;
}
const Class WeakMapObject::class_ = {
"WeakMap",
JSCLASS_HAS_PRIVATE | JSCLASS_IMPLEMENTS_BARRIERS |
JSCLASS_HAS_CACHED_PROTO(JSProto_WeakMap),
JS_PropertyStub, /* addProperty */
JS_DeletePropertyStub, /* delProperty */
JS_PropertyStub, /* getProperty */
JS_StrictPropertyStub, /* setProperty */
JS_EnumerateStub,
JS_ResolveStub,
JS_ConvertStub,
WeakMap_finalize,
nullptr, /* call */
nullptr, /* construct */
nullptr, /* xdrObject */
WeakMap_mark
};
static const JSFunctionSpec weak_map_methods[] = {
JS_FN("has", WeakMap_has, 1, 0),
JS_FN("get", WeakMap_get, 2, 0),
JS_FN("delete", WeakMap_delete, 1, 0),
JS_FN("set", WeakMap_set, 2, 0),
JS_FN("clear", WeakMap_clear, 0, 0),
JS_FS_END
};
JSObject*
js_InitWeakMapClass(JSContext* cx, HandleObject obj)
{
JS_ASSERT(obj->isNative());
Rooted<GlobalObject*> global(cx, &obj->as<GlobalObject>());
RootedObject weakMapProto(cx, global->createBlankPrototype(cx, &WeakMapObject::class_));
if (!weakMapProto)
return nullptr;
RootedFunction ctor(cx, global->createConstructor(cx, WeakMap_construct,
cx->names().WeakMap, 1));
if (!ctor)
return nullptr;
if (!LinkConstructorAndPrototype(cx, ctor, weakMapProto))
return nullptr;
if (!DefinePropertiesAndBrand(cx, weakMapProto, nullptr, weak_map_methods))
return nullptr;
if (!GlobalObject::initBuiltinConstructor(cx, global, JSProto_WeakMap, ctor, weakMapProto))
return nullptr;
return weakMapProto;
}