1 // Copyright 2016 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "src/builtins/builtins-utils-inl.h"
6 #include "src/builtins/builtins.h"
7 #include "src/conversions.h"
8 #include "src/counters.h"
9 #include "src/heap/factory.h"
10 #include "src/isolate.h"
11 #include "src/objects-inl.h"
12 #include "src/objects/js-array-buffer-inl.h"
13
14 namespace v8 {
15 namespace internal {
16
17 // -----------------------------------------------------------------------------
18 // ES #sec-dataview-objects
19
20 // ES #sec-dataview-constructor
BUILTIN(DataViewConstructor)21 BUILTIN(DataViewConstructor) {
22 HandleScope scope(isolate);
23 if (args.new_target()->IsUndefined(isolate)) { // [[Call]]
24 THROW_NEW_ERROR_RETURN_FAILURE(
25 isolate, NewTypeError(MessageTemplate::kConstructorNotFunction,
26 isolate->factory()->NewStringFromAsciiChecked(
27 "DataView")));
28 }
29 // [[Construct]]
30 Handle<JSFunction> target = args.target();
31 Handle<JSReceiver> new_target = Handle<JSReceiver>::cast(args.new_target());
32 Handle<Object> buffer = args.atOrUndefined(isolate, 1);
33 Handle<Object> byte_offset = args.atOrUndefined(isolate, 2);
34 Handle<Object> byte_length = args.atOrUndefined(isolate, 3);
35
36 // 2. If Type(buffer) is not Object, throw a TypeError exception.
37 // 3. If buffer does not have an [[ArrayBufferData]] internal slot, throw a
38 // TypeError exception.
39 if (!buffer->IsJSArrayBuffer()) {
40 THROW_NEW_ERROR_RETURN_FAILURE(
41 isolate, NewTypeError(MessageTemplate::kDataViewNotArrayBuffer));
42 }
43 Handle<JSArrayBuffer> array_buffer = Handle<JSArrayBuffer>::cast(buffer);
44
45 // 4. Let offset be ? ToIndex(byteOffset).
46 Handle<Object> offset;
47 ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
48 isolate, offset,
49 Object::ToIndex(isolate, byte_offset, MessageTemplate::kInvalidOffset));
50
51 // 5. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
52 // We currently violate the specification at this point. TODO: Fix that.
53
54 // 6. Let bufferByteLength be the value of buffer's
55 // [[ArrayBufferByteLength]] internal slot.
56 double const buffer_byte_length = array_buffer->byte_length()->Number();
57
58 // 7. If offset > bufferByteLength, throw a RangeError exception.
59 if (offset->Number() > buffer_byte_length) {
60 THROW_NEW_ERROR_RETURN_FAILURE(
61 isolate, NewRangeError(MessageTemplate::kInvalidOffset, offset));
62 }
63
64 Handle<Object> view_byte_length;
65 if (byte_length->IsUndefined(isolate)) {
66 // 8. If byteLength is either not present or undefined, then
67 // a. Let viewByteLength be bufferByteLength - offset.
68 view_byte_length =
69 isolate->factory()->NewNumber(buffer_byte_length - offset->Number());
70 } else {
71 // 9. Else,
72 // a. Let viewByteLength be ? ToIndex(byteLength).
73 // b. If offset+viewByteLength > bufferByteLength, throw a
74 // RangeError exception.
75 ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
76 isolate, view_byte_length,
77 Object::ToIndex(isolate, byte_length,
78 MessageTemplate::kInvalidDataViewLength));
79 if (offset->Number() + view_byte_length->Number() > buffer_byte_length) {
80 THROW_NEW_ERROR_RETURN_FAILURE(
81 isolate, NewRangeError(MessageTemplate::kInvalidDataViewLength));
82 }
83 }
84
85 // 10. Let O be ? OrdinaryCreateFromConstructor(NewTarget,
86 // "%DataViewPrototype%", «[[DataView]], [[ViewedArrayBuffer]],
87 // [[ByteLength]], [[ByteOffset]]»).
88 Handle<JSObject> result;
89 ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
90 JSObject::New(target, new_target));
91 for (int i = 0; i < ArrayBufferView::kEmbedderFieldCount; ++i) {
92 Handle<JSDataView>::cast(result)->SetEmbedderField(i, Smi::kZero);
93 }
94
95 // 11. Set O's [[ViewedArrayBuffer]] internal slot to buffer.
96 Handle<JSDataView>::cast(result)->set_buffer(*array_buffer);
97
98 // 12. Set O's [[ByteLength]] internal slot to viewByteLength.
99 Handle<JSDataView>::cast(result)->set_byte_length(*view_byte_length);
100
101 // 13. Set O's [[ByteOffset]] internal slot to offset.
102 Handle<JSDataView>::cast(result)->set_byte_offset(*offset);
103
104 // 14. Return O.
105 return *result;
106 }
107
108 } // namespace internal
109 } // namespace v8
110