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/StringType.h"
14
15 #include "vm/JSObject-inl.h"
16 #include "vm/TypeInference-inl.h"
17
18 namespace js {
19
setLength(JSContext * cx,uint32_t length)20 inline void ArrayObject::setLength(JSContext* cx, uint32_t length) {
21 MOZ_ASSERT(lengthIsWritable());
22 MOZ_ASSERT_IF(length != getElementsHeader()->length,
23 !denseElementsAreFrozen());
24
25 if (length > INT32_MAX) {
26 /* Track objects with overflowing lengths in type information. */
27 MarkObjectGroupFlags(cx, this, OBJECT_FLAG_LENGTH_OVERFLOW);
28 }
29
30 getElementsHeader()->length = length;
31 }
32
createArrayInternal(JSContext * cx,gc::AllocKind kind,gc::InitialHeap heap,HandleShape shape,HandleObjectGroup group,AutoSetNewObjectMetadata &)33 /* static */ inline ArrayObject* ArrayObject::createArrayInternal(
34 JSContext* cx, gc::AllocKind kind, gc::InitialHeap heap, HandleShape shape,
35 HandleObjectGroup group, AutoSetNewObjectMetadata&) {
36 const js::Class* clasp = group->clasp();
37 MOZ_ASSERT(shape && group);
38 MOZ_ASSERT(clasp == shape->getObjectClass());
39 MOZ_ASSERT(clasp == &ArrayObject::class_);
40 MOZ_ASSERT_IF(clasp->hasFinalize(), heap == gc::TenuredHeap);
41 MOZ_ASSERT_IF(group->hasUnanalyzedPreliminaryObjects(),
42 heap == js::gc::TenuredHeap);
43
44 // Arrays can use their fixed slots to store elements, so can't have shapes
45 // which allow named properties to be stored in the fixed slots.
46 MOZ_ASSERT(shape->numFixedSlots() == 0);
47
48 size_t nDynamicSlots = dynamicSlotsCount(0, shape->slotSpan(), clasp);
49 JSObject* obj = js::Allocate<JSObject>(cx, kind, nDynamicSlots, heap, clasp);
50 if (!obj) return nullptr;
51
52 ArrayObject* aobj = static_cast<ArrayObject*>(obj);
53 aobj->initGroup(group);
54 aobj->initShape(shape);
55 // NOTE: Dynamic slots are created internally by Allocate<JSObject>.
56 if (!nDynamicSlots) aobj->initSlots(nullptr);
57
58 MOZ_ASSERT(clasp->shouldDelayMetadataBuilder());
59 cx->compartment()->setObjectPendingMetadata(cx, aobj);
60
61 return aobj;
62 }
63
finishCreateArray(ArrayObject * obj,HandleShape shape,AutoSetNewObjectMetadata & metadata)64 /* static */ inline ArrayObject* ArrayObject::finishCreateArray(
65 ArrayObject* obj, HandleShape shape, AutoSetNewObjectMetadata& metadata) {
66 size_t span = shape->slotSpan();
67 if (span) obj->initializeSlotRange(0, span);
68
69 gc::TraceCreateObject(obj);
70
71 return obj;
72 }
73
createArray(JSContext * cx,gc::AllocKind kind,gc::InitialHeap heap,HandleShape shape,HandleObjectGroup group,uint32_t length,AutoSetNewObjectMetadata & metadata)74 /* static */ inline ArrayObject* ArrayObject::createArray(
75 JSContext* cx, gc::AllocKind kind, gc::InitialHeap heap, HandleShape shape,
76 HandleObjectGroup group, uint32_t length,
77 AutoSetNewObjectMetadata& metadata) {
78 ArrayObject* obj =
79 createArrayInternal(cx, kind, heap, shape, group, metadata);
80 if (!obj) return nullptr;
81
82 uint32_t capacity =
83 gc::GetGCKindSlots(kind) - ObjectElements::VALUES_PER_HEADER;
84
85 obj->setFixedElements();
86 new (obj->getElementsHeader()) ObjectElements(capacity, length);
87
88 return finishCreateArray(obj, shape, metadata);
89 }
90
createCopyOnWriteArray(JSContext * cx,gc::InitialHeap heap,HandleArrayObject sharedElementsOwner)91 /* static */ inline ArrayObject* ArrayObject::createCopyOnWriteArray(
92 JSContext* cx, gc::InitialHeap heap,
93 HandleArrayObject sharedElementsOwner) {
94 MOZ_ASSERT(sharedElementsOwner->getElementsHeader()->isCopyOnWrite());
95 MOZ_ASSERT(sharedElementsOwner->getElementsHeader()->ownerObject() ==
96 sharedElementsOwner);
97
98 // Use the smallest allocation kind for the array, as it can't have any
99 // fixed slots (see the assert in createArrayInternal) and will not be using
100 // its fixed elements.
101 gc::AllocKind kind = gc::AllocKind::OBJECT0_BACKGROUND;
102
103 AutoSetNewObjectMetadata metadata(cx);
104 RootedShape shape(cx, sharedElementsOwner->lastProperty());
105 RootedObjectGroup group(cx, sharedElementsOwner->group());
106 ArrayObject* obj =
107 createArrayInternal(cx, kind, heap, shape, group, metadata);
108 if (!obj) return nullptr;
109
110 obj->elements_ = sharedElementsOwner->getDenseElementsAllowCopyOnWrite();
111
112 return finishCreateArray(obj, shape, metadata);
113 }
114
115 } // namespace js
116
117 #endif // vm_ArrayObject_inl_h
118