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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_OBJECTS_JS_WEAK_REFS_H_
#define V8_OBJECTS_JS_WEAK_REFS_H_
#include "src/objects/js-objects.h"
#include "src/objects/microtask.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
class NativeContext;
class WeakCell;
// FinalizationGroup object from the JS Weak Refs spec proposal:
// https://github.com/tc39/proposal-weakrefs
class JSFinalizationGroup : public JSObject {
public:
DECL_PRINTER(JSFinalizationGroup)
EXPORT_DECL_VERIFIER(JSFinalizationGroup)
DECL_CAST(JSFinalizationGroup)
DECL_ACCESSORS(native_context, NativeContext)
DECL_ACCESSORS(cleanup, Object)
DECL_ACCESSORS(active_cells, Object)
DECL_ACCESSORS(cleared_cells, Object)
DECL_ACCESSORS(key_map, Object)
// For storing a list of JSFinalizationGroup objects in NativeContext.
DECL_ACCESSORS(next, Object)
DECL_INT_ACCESSORS(flags)
inline static void Register(Handle<JSFinalizationGroup> finalization_group,
Handle<JSReceiver> target,
Handle<Object> holdings, Handle<Object> key,
Isolate* isolate);
inline static void Unregister(Handle<JSFinalizationGroup> finalization_group,
Handle<Object> key, Isolate* isolate);
// Returns true if the cleared_cells list is non-empty.
inline bool NeedsCleanup() const;
inline bool scheduled_for_cleanup() const;
inline void set_scheduled_for_cleanup(bool scheduled_for_cleanup);
// Remove the first cleared WeakCell from the cleared_cells
// list (assumes there is one) and return its holdings.
inline static Object PopClearedCellHoldings(
Handle<JSFinalizationGroup> finalization_group, Isolate* isolate);
// Constructs an iterator for the WeakCells in the cleared_cells list and
// calls the user's cleanup function.
static void Cleanup(Handle<JSFinalizationGroup> finalization_group,
Isolate* isolate);
// Layout description.
#define JS_FINALIZATION_GROUP_FIELDS(V) \
V(kNativeContextOffset, kTaggedSize) \
V(kCleanupOffset, kTaggedSize) \
V(kActiveCellsOffset, kTaggedSize) \
V(kClearedCellsOffset, kTaggedSize) \
V(kKeyMapOffset, kTaggedSize) \
V(kNextOffset, kTaggedSize) \
V(kFlagsOffset, kTaggedSize) \
/* Header size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
JS_FINALIZATION_GROUP_FIELDS)
#undef JS_FINALIZATION_GROUP_FIELDS
// Bitfields in flags.
class ScheduledForCleanupField : public BitField<bool, 0, 1> {};
OBJECT_CONSTRUCTORS(JSFinalizationGroup, JSObject);
};
// Internal object for storing weak references in JSFinalizationGroup.
class WeakCell : public HeapObject {
public:
DECL_PRINTER(WeakCell)
EXPORT_DECL_VERIFIER(WeakCell)
DECL_CAST(WeakCell)
DECL_ACCESSORS(finalization_group, Object)
DECL_ACCESSORS(target, HeapObject)
DECL_ACCESSORS(holdings, Object)
// For storing doubly linked lists of WeakCells in JSFinalizationGroup's
// "active_cells" and "cleared_cells" lists.
DECL_ACCESSORS(prev, Object)
DECL_ACCESSORS(next, Object)
// For storing doubly linked lists of WeakCells per key in
// JSFinalizationGroup's key-based hashmap. WeakCell also needs to know its
// key, so that we can remove the key from the key_map when we remove the last
// WeakCell associated with it.
DECL_ACCESSORS(key, Object)
DECL_ACCESSORS(key_list_prev, Object)
DECL_ACCESSORS(key_list_next, Object)
// Layout description.
#define WEAK_CELL_FIELDS(V) \
V(kFinalizationGroupOffset, kTaggedSize) \
V(kTargetOffset, kTaggedSize) \
V(kHoldingsOffset, kTaggedSize) \
V(kPrevOffset, kTaggedSize) \
V(kNextOffset, kTaggedSize) \
V(kKeyOffset, kTaggedSize) \
V(kKeyListPrevOffset, kTaggedSize) \
V(kKeyListNextOffset, kTaggedSize) \
/* Header size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, WEAK_CELL_FIELDS)
#undef WEAK_CELL_FIELDS
class BodyDescriptor;
// Nullify is called during GC and it modifies the pointers in WeakCell and
// JSFinalizationGroup. Thus we need to tell the GC about the modified slots
// via the gc_notify_updated_slot function. The normal write barrier is not
// enough, since it's disabled before GC.
inline void Nullify(
Isolate* isolate,
std::function<void(HeapObject object, ObjectSlot slot, Object target)>
gc_notify_updated_slot);
inline void RemoveFromFinalizationGroupCells(Isolate* isolate);
OBJECT_CONSTRUCTORS(WeakCell, HeapObject);
};
class JSWeakRef : public JSObject {
public:
DECL_PRINTER(JSWeakRef)
EXPORT_DECL_VERIFIER(JSWeakRef)
DECL_CAST(JSWeakRef)
DECL_ACCESSORS(target, HeapObject)
// Layout description.
#define JS_WEAK_REF_FIELDS(V) \
V(kTargetOffset, kTaggedSize) \
/* Header size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize, JS_WEAK_REF_FIELDS)
#undef JS_WEAK_REF_FIELDS
class BodyDescriptor;
OBJECT_CONSTRUCTORS(JSWeakRef, JSObject);
};
class FinalizationGroupCleanupJobTask : public Microtask {
public:
DECL_ACCESSORS(finalization_group, JSFinalizationGroup)
DECL_CAST(FinalizationGroupCleanupJobTask)
DECL_VERIFIER(FinalizationGroupCleanupJobTask)
DECL_PRINTER(FinalizationGroupCleanupJobTask)
// Layout description.
#define FINALIZATION_GROUP_CLEANUP_JOB_TASK_FIELDS(V) \
V(kFinalizationGroupOffset, kTaggedSize) \
/* Total size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(Microtask::kHeaderSize,
FINALIZATION_GROUP_CLEANUP_JOB_TASK_FIELDS)
#undef FINALIZATION_GROUP_CLEANUP_JOB_TASK_FIELDS
OBJECT_CONSTRUCTORS(FinalizationGroupCleanupJobTask, Microtask);
};
class JSFinalizationGroupCleanupIterator : public JSObject {
public:
DECL_PRINTER(JSFinalizationGroupCleanupIterator)
DECL_VERIFIER(JSFinalizationGroupCleanupIterator)
DECL_CAST(JSFinalizationGroupCleanupIterator)
DECL_ACCESSORS(finalization_group, JSFinalizationGroup)
// Layout description.
#define JS_FINALIZATION_GROUP_CLEANUP_ITERATOR_FIELDS(V) \
V(kFinalizationGroupOffset, kTaggedSize) \
/* Header size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(JSObject::kHeaderSize,
JS_FINALIZATION_GROUP_CLEANUP_ITERATOR_FIELDS)
#undef JS_FINALIZATION_GROUP_CLEANUP_ITERATOR_FIELDS
OBJECT_CONSTRUCTORS(JSFinalizationGroupCleanupIterator, JSObject);
};
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_JS_WEAK_REFS_H_
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