// Copyright 2016 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. #include "src/builtins/builtins-utils-inl.h" #include "src/builtins/builtins.h" #include "src/execution/isolate.h" #include "src/heap/factory.h" #include "src/logging/counters.h" #include "src/numbers/conversions.h" #include "src/objects/js-array-buffer-inl.h" #include "src/objects/objects-inl.h" namespace v8 { namespace internal { // ----------------------------------------------------------------------------- // ES #sec-dataview-objects // ES #sec-dataview-constructor BUILTIN(DataViewConstructor) { HandleScope scope(isolate); if (args.new_target()->IsUndefined(isolate)) { // [[Call]] THROW_NEW_ERROR_RETURN_FAILURE( isolate, NewTypeError(MessageTemplate::kConstructorNotFunction, isolate->factory()->NewStringFromAsciiChecked( "DataView"))); } // [[Construct]] Handle<JSFunction> target = args.target(); Handle<JSReceiver> new_target = Handle<JSReceiver>::cast(args.new_target()); Handle<Object> buffer = args.atOrUndefined(isolate, 1); Handle<Object> byte_offset = args.atOrUndefined(isolate, 2); Handle<Object> byte_length = args.atOrUndefined(isolate, 3); // 2. If Type(buffer) is not Object, throw a TypeError exception. // 3. If buffer does not have an [[ArrayBufferData]] internal slot, throw a // TypeError exception. if (!buffer->IsJSArrayBuffer()) { THROW_NEW_ERROR_RETURN_FAILURE( isolate, NewTypeError(MessageTemplate::kDataViewNotArrayBuffer)); } Handle<JSArrayBuffer> array_buffer = Handle<JSArrayBuffer>::cast(buffer); // 4. Let offset be ? ToIndex(byteOffset). ASSIGN_RETURN_FAILURE_ON_EXCEPTION( isolate, byte_offset, Object::ToIndex(isolate, byte_offset, MessageTemplate::kInvalidOffset)); size_t view_byte_offset = byte_offset->Number(); // 5. If IsDetachedBuffer(buffer) is true, throw a TypeError exception. // We currently violate the specification at this point. TODO: Fix that. // 6. Let bufferByteLength be the value of buffer's // [[ArrayBufferByteLength]] internal slot. size_t const buffer_byte_length = array_buffer->byte_length(); // 7. If offset > bufferByteLength, throw a RangeError exception. if (view_byte_offset > buffer_byte_length) { THROW_NEW_ERROR_RETURN_FAILURE( isolate, NewRangeError(MessageTemplate::kInvalidOffset, byte_offset)); } size_t view_byte_length; if (byte_length->IsUndefined(isolate)) { // 8. If byteLength is either not present or undefined, then // a. Let viewByteLength be bufferByteLength - offset. view_byte_length = buffer_byte_length - view_byte_offset; } else { // 9. Else, // a. Let viewByteLength be ? ToIndex(byteLength). // b. If offset+viewByteLength > bufferByteLength, throw a // RangeError exception. ASSIGN_RETURN_FAILURE_ON_EXCEPTION( isolate, byte_length, Object::ToIndex(isolate, byte_length, MessageTemplate::kInvalidDataViewLength)); if (view_byte_offset + byte_length->Number() > buffer_byte_length) { THROW_NEW_ERROR_RETURN_FAILURE( isolate, NewRangeError(MessageTemplate::kInvalidDataViewLength)); } view_byte_length = byte_length->Number(); } // 10. Let O be ? OrdinaryCreateFromConstructor(NewTarget, // "%DataViewPrototype%", «[[DataView]], [[ViewedArrayBuffer]], // [[ByteLength]], [[ByteOffset]]»). Handle<JSObject> result; ASSIGN_RETURN_FAILURE_ON_EXCEPTION( isolate, result, JSObject::New(target, new_target, Handle<AllocationSite>::null())); for (int i = 0; i < ArrayBufferView::kEmbedderFieldCount; ++i) { // TODO(v8:10391, saelo): Handle external pointers in EmbedderDataSlot Handle<JSDataView>::cast(result)->SetEmbedderField(i, Smi::zero()); } // 11. Set O's [[ViewedArrayBuffer]] internal slot to buffer. Handle<JSDataView>::cast(result)->set_buffer(*array_buffer); // 12. Set O's [[ByteLength]] internal slot to viewByteLength. Handle<JSDataView>::cast(result)->set_byte_length(view_byte_length); // 13. Set O's [[ByteOffset]] internal slot to offset. Handle<JSDataView>::cast(result)->set_byte_offset(view_byte_offset); Handle<JSDataView>::cast(result)->AllocateExternalPointerEntries(isolate); Handle<JSDataView>::cast(result)->set_data_pointer( isolate, static_cast<uint8_t*>(array_buffer->backing_store()) + view_byte_offset); // 14. Return O. return *result; } } // namespace internal } // namespace v8