1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 * vim: set ts=8 sts=4 et sw=4 tw=99:
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #ifndef vm_ArrayObject_inl_h
8 #define vm_ArrayObject_inl_h
9
10 #include "vm/ArrayObject.h"
11
12 #include "gc/GCTrace.h"
13 #include "vm/String.h"
14
15 #include "jsgcinlines.h"
16 #include "jsobjinlines.h"
17
18 #include "vm/TypeInference-inl.h"
19
20 namespace js {
21
22 inline void
setLength(ExclusiveContext * cx,uint32_t length)23 ArrayObject::setLength(ExclusiveContext* cx, uint32_t length)
24 {
25 MOZ_ASSERT(lengthIsWritable());
26
27 if (length > INT32_MAX) {
28 /* Track objects with overflowing lengths in type information. */
29 MarkObjectGroupFlags(cx, this, OBJECT_FLAG_LENGTH_OVERFLOW);
30 }
31
32 getElementsHeader()->length = length;
33 }
34
35 /* static */ inline ArrayObject*
createArrayInternal(ExclusiveContext * cx,gc::AllocKind kind,gc::InitialHeap heap,HandleShape shape,HandleObjectGroup group,AutoSetNewObjectMetadata &)36 ArrayObject::createArrayInternal(ExclusiveContext* cx, gc::AllocKind kind, gc::InitialHeap heap,
37 HandleShape shape, HandleObjectGroup group,
38 AutoSetNewObjectMetadata&)
39 {
40 // Create a new array and initialize everything except for its elements.
41 MOZ_ASSERT(shape && group);
42 MOZ_ASSERT(group->clasp() == shape->getObjectClass());
43 MOZ_ASSERT(group->clasp() == &ArrayObject::class_);
44 MOZ_ASSERT_IF(group->clasp()->finalize, heap == gc::TenuredHeap);
45 MOZ_ASSERT_IF(group->hasUnanalyzedPreliminaryObjects(),
46 heap == js::gc::TenuredHeap);
47 MOZ_ASSERT(group->clasp()->shouldDelayMetadataCallback());
48
49 // Arrays can use their fixed slots to store elements, so can't have shapes
50 // which allow named properties to be stored in the fixed slots.
51 MOZ_ASSERT(shape->numFixedSlots() == 0);
52
53 size_t nDynamicSlots = dynamicSlotsCount(0, shape->slotSpan(), group->clasp());
54 JSObject* obj = Allocate<JSObject>(cx, kind, nDynamicSlots, heap, group->clasp());
55 if (!obj)
56 return nullptr;
57
58 static_cast<ArrayObject*>(obj)->shape_.init(shape);
59 static_cast<ArrayObject*>(obj)->group_.init(group);
60
61 cx->compartment()->setObjectPendingMetadata(cx, obj);
62 return &obj->as<ArrayObject>();
63 }
64
65 /* static */ inline ArrayObject*
finishCreateArray(ArrayObject * obj,HandleShape shape,AutoSetNewObjectMetadata & metadata)66 ArrayObject::finishCreateArray(ArrayObject* obj, HandleShape shape, AutoSetNewObjectMetadata& metadata)
67 {
68 size_t span = shape->slotSpan();
69 if (span)
70 obj->initializeSlotRange(0, span);
71
72 gc::TraceCreateObject(obj);
73
74 return obj;
75 }
76
77 /* static */ inline ArrayObject*
createArray(ExclusiveContext * cx,gc::AllocKind kind,gc::InitialHeap heap,HandleShape shape,HandleObjectGroup group,uint32_t length,AutoSetNewObjectMetadata & metadata)78 ArrayObject::createArray(ExclusiveContext* cx, gc::AllocKind kind, gc::InitialHeap heap,
79 HandleShape shape, HandleObjectGroup group,
80 uint32_t length, AutoSetNewObjectMetadata& metadata)
81 {
82 ArrayObject* obj = createArrayInternal(cx, kind, heap, shape, group, metadata);
83 if (!obj)
84 return nullptr;
85
86 uint32_t capacity = gc::GetGCKindSlots(kind) - ObjectElements::VALUES_PER_HEADER;
87
88 obj->setFixedElements();
89 new (obj->getElementsHeader()) ObjectElements(capacity, length);
90
91 return finishCreateArray(obj, shape, metadata);
92 }
93
94 /* static */ inline ArrayObject*
createCopyOnWriteArray(ExclusiveContext * cx,gc::InitialHeap heap,HandleArrayObject sharedElementsOwner)95 ArrayObject::createCopyOnWriteArray(ExclusiveContext* cx, gc::InitialHeap heap,
96 HandleArrayObject sharedElementsOwner)
97 {
98 MOZ_ASSERT(sharedElementsOwner->getElementsHeader()->isCopyOnWrite());
99 MOZ_ASSERT(sharedElementsOwner->getElementsHeader()->ownerObject() == sharedElementsOwner);
100
101 // Use the smallest allocation kind for the array, as it can't have any
102 // fixed slots (see the assert in createArrayInternal) and will not be using
103 // its fixed elements.
104 gc::AllocKind kind = gc::AllocKind::OBJECT0_BACKGROUND;
105
106 AutoSetNewObjectMetadata metadata(cx);
107 RootedShape shape(cx, sharedElementsOwner->lastProperty());
108 RootedObjectGroup group(cx, sharedElementsOwner->group());
109 ArrayObject* obj = createArrayInternal(cx, kind, heap, shape, group, metadata);
110 if (!obj)
111 return nullptr;
112
113 obj->elements_ = sharedElementsOwner->getDenseElementsAllowCopyOnWrite();
114
115 return finishCreateArray(obj, shape, metadata);
116 }
117
118 } // namespace js
119
120 #endif // vm_ArrayObject_inl_h
121