src/objects/js-array-buffer.cc - v8/v8 - Git at Google

 // 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.

 #include "src/objects/js-array-buffer.h"
 #include "src/objects/js-array-buffer-inl.h"

 #include "src/execution/protectors-inl.h"
 #include "src/logging/counters.h"
 #include "src/objects/property-descriptor.h"

 namespace v8 {
 namespace internal {

 namespace {

 bool CanonicalNumericIndexString(Isolate* isolate, Handle<Object> s,
                                  Handle<Object>* index) {
   DCHECK(s->IsString() || s->IsSmi());

   Handle<Object> result;
   if (s->IsSmi()) {
     result = s;
   } else {
     result = String::ToNumber(isolate, Handle<String>::cast(s));
     if (!result->IsMinusZero()) {
       Handle<String> str = Object::ToString(isolate, result).ToHandleChecked();
       // Avoid treating strings like "2E1" and "20" as the same key.
       if (!str->SameValue(*s)) return false;
     }
   }
   *index = result;
   return true;
 }
 }  // anonymous namespace

 void JSArrayBuffer::Setup(SharedFlag shared,
                           std::shared_ptr<BackingStore> backing_store) {
   clear_padding();
   set_bit_field(0);
   set_is_shared(shared == SharedFlag::kShared);
   set_is_detachable(shared != SharedFlag::kShared);
   for (int i = 0; i < v8::ArrayBuffer::kEmbedderFieldCount; i++) {
     SetEmbedderField(i, Smi::zero());
   }
   set_extension(nullptr);
   if (!backing_store) {
     set_backing_store(GetIsolate(), nullptr);
     set_byte_length(0);
   } else {
     Attach(std::move(backing_store));
   }
   if (shared == SharedFlag::kShared) {
     GetIsolate()->CountUsage(
         v8::Isolate::UseCounterFeature::kSharedArrayBufferConstructed);
   }
 }

 void JSArrayBuffer::Attach(std::shared_ptr<BackingStore> backing_store) {
   DCHECK_NOT_NULL(backing_store);
   DCHECK_EQ(is_shared(), backing_store->is_shared());
   DCHECK(!was_detached());
   Isolate* isolate = GetIsolate();
   set_backing_store(isolate, backing_store->buffer_start());
   set_byte_length(backing_store->byte_length());
   if (backing_store->is_wasm_memory()) set_is_detachable(false);
   if (!backing_store->free_on_destruct()) set_is_external(true);
   if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
     Heap* heap = isolate->heap();
     ArrayBufferExtension* extension = EnsureExtension();
     size_t bytes = backing_store->PerIsolateAccountingLength();
     extension->set_accounting_length(bytes);
     extension->set_backing_store(std::move(backing_store));
     heap->AppendArrayBufferExtension(*this, extension);
   } else {
     isolate->heap()->RegisterBackingStore(*this, std::move(backing_store));
   }
 }

 void JSArrayBuffer::Detach(bool force_for_wasm_memory) {
   if (was_detached()) return;

   if (force_for_wasm_memory) {
     // Skip the is_detachable() check.
   } else if (!is_detachable()) {
     // Not detachable, do nothing.
     return;
   }

   Isolate* const isolate = GetIsolate();
   if (backing_store()) {
     std::shared_ptr<BackingStore> backing_store;
     if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
       backing_store = RemoveExtension();
     } else {
       backing_store = isolate->heap()->UnregisterBackingStore(*this);
     }
     CHECK_IMPLIES(force_for_wasm_memory, backing_store->is_wasm_memory());
   }

   if (Protectors::IsArrayBufferDetachingIntact(isolate)) {
     Protectors::InvalidateArrayBufferDetaching(isolate);
   }

   DCHECK(!is_shared());
   DCHECK(!is_asmjs_memory());
   set_backing_store(isolate, nullptr);
   set_byte_length(0);
   set_was_detached(true);
 }

 std::shared_ptr<BackingStore> JSArrayBuffer::GetBackingStore() {
   if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
     if (!extension()) return nullptr;
     return extension()->backing_store();
   } else {
     return GetIsolate()->heap()->LookupBackingStore(*this);
   }
 }

 ArrayBufferExtension* JSArrayBuffer::EnsureExtension() {
   DCHECK(V8_ARRAY_BUFFER_EXTENSION_BOOL);
   ArrayBufferExtension* extension = this->extension();
   if (extension != nullptr) return extension;

   extension = new ArrayBufferExtension(std::shared_ptr<BackingStore>());
   set_extension(extension);
   return extension;
 }

 std::shared_ptr<BackingStore> JSArrayBuffer::RemoveExtension() {
   ArrayBufferExtension* extension = this->extension();
   DCHECK_NOT_NULL(extension);
   auto result = extension->RemoveBackingStore();
   // Remove pointer to extension such that the next GC will free it
   // automatically.
   set_extension(nullptr);
   return result;
 }

 void JSArrayBuffer::MarkExtension() {
   ArrayBufferExtension* extension = this->extension();
   if (extension) {
     extension->Mark();
   }
 }

 void JSArrayBuffer::YoungMarkExtension() {
   ArrayBufferExtension* extension = this->extension();
   if (extension) {
     extension->YoungMark();
   }
 }

 void JSArrayBuffer::YoungMarkExtensionPromoted() {
   ArrayBufferExtension* extension = this->extension();
   if (extension) {
     extension->YoungMarkPromoted();
   }
 }

 Handle<JSArrayBuffer> JSTypedArray::GetBuffer() {
   Isolate* isolate = GetIsolate();
   Handle<JSTypedArray> self(*this, isolate);
   DCHECK(IsTypedArrayElementsKind(self->GetElementsKind()));

   Handle<JSArrayBuffer> array_buffer(JSArrayBuffer::cast(self->buffer()),
                                      isolate);
   if (!is_on_heap()) {
     // Already is off heap, so return the existing buffer.
     return array_buffer;
   }

   // The existing array buffer should be empty.
   DCHECK_NULL(array_buffer->backing_store());

   // Allocate a new backing store and attach it to the existing array buffer.
   size_t byte_length = self->byte_length();
   auto backing_store =
       BackingStore::Allocate(isolate, byte_length, SharedFlag::kNotShared,
                              InitializedFlag::kUninitialized);

   if (!backing_store) {
     isolate->heap()->FatalProcessOutOfMemory("JSTypedArray::GetBuffer");
   }

   // Copy the elements into the backing store of the array buffer.
   if (byte_length > 0) {
     memcpy(backing_store->buffer_start(), self->DataPtr(), byte_length);
   }

   // Attach the backing store to the array buffer.
   array_buffer->Setup(SharedFlag::kNotShared, std::move(backing_store));

   // Clear the elements of the typed array.
   self->set_elements(ReadOnlyRoots(isolate).empty_byte_array());
   self->SetOffHeapDataPtr(isolate, array_buffer->backing_store(), 0);
   DCHECK(!self->is_on_heap());

   return array_buffer;
 }

 // ES#sec-integer-indexed-exotic-objects-defineownproperty-p-desc
 // static
 Maybe<bool> JSTypedArray::DefineOwnProperty(Isolate* isolate,
                                             Handle<JSTypedArray> o,
                                             Handle<Object> key,
                                             PropertyDescriptor* desc,
                                             Maybe<ShouldThrow> should_throw) {
   // 1. Assert: IsPropertyKey(P) is true.
   DCHECK(key->IsName() || key->IsNumber());
   // 2. Assert: O is an Object that has a [[ViewedArrayBuffer]] internal slot.
   // 3. If Type(P) is String, then
   if (key->IsString() || key->IsSmi()) {
     // 3a. Let numericIndex be ! CanonicalNumericIndexString(P)
     // 3b. If numericIndex is not undefined, then
     Handle<Object> numeric_index;
     if (CanonicalNumericIndexString(isolate, key, &numeric_index)) {
       // 3b i. If IsInteger(numericIndex) is false, return false.
       // 3b ii. If numericIndex = -0, return false.
       // 3b iii. If numericIndex < 0, return false.
       size_t index;
       if (numeric_index->IsMinusZero() ||
           !numeric_index->ToIntegerIndex(&index)) {
         RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
                        NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
       }
       // 3b iv. Let length be O.[[ArrayLength]].
       size_t length = o->length();
       // 3b v. If numericIndex ≥ length, return false.
       if (o->WasDetached() || index >= length) {
         RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
                        NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
       }
       // 3b vi. If IsAccessorDescriptor(Desc) is true, return false.
       if (PropertyDescriptor::IsAccessorDescriptor(desc)) {
         RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
                        NewTypeError(MessageTemplate::kRedefineDisallowed, key));
       }
       // 3b vii. If Desc has a [[Configurable]] field and if
       //         Desc.[[Configurable]] is true, return false.
       // 3b viii. If Desc has an [[Enumerable]] field and if Desc.[[Enumerable]]
       //          is false, return false.
       // 3b ix. If Desc has a [[Writable]] field and if Desc.[[Writable]] is
       //        false, return false.
       if ((desc->has_configurable() && desc->configurable()) ||
           (desc->has_enumerable() && !desc->enumerable()) ||
           (desc->has_writable() && !desc->writable())) {
         RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
                        NewTypeError(MessageTemplate::kRedefineDisallowed, key));
       }
       // 3b x. If Desc has a [[Value]] field, then
       //   3b x 1. Let value be Desc.[[Value]].
       //   3b x 2. Return ? IntegerIndexedElementSet(O, numericIndex, value).
       if (desc->has_value()) {
         if (!desc->has_configurable()) desc->set_configurable(false);
         if (!desc->has_enumerable()) desc->set_enumerable(true);
         if (!desc->has_writable()) desc->set_writable(true);
         Handle<Object> value = desc->value();
         LookupIterator it(isolate, o, index, LookupIterator::OWN);
         RETURN_ON_EXCEPTION_VALUE(
             isolate,
             DefineOwnPropertyIgnoreAttributes(&it, value, desc->ToAttributes()),
             Nothing<bool>());
       }
       // 3b xi. Return true.
       return Just(true);
     }
   }
   // 4. Return ! OrdinaryDefineOwnProperty(O, P, Desc).
   return OrdinaryDefineOwnProperty(isolate, o, key, desc, should_throw);
 }

 ExternalArrayType JSTypedArray::type() {
   switch (map().elements_kind()) {
 #define ELEMENTS_KIND_TO_ARRAY_TYPE(Type, type, TYPE, ctype) \
   case TYPE##_ELEMENTS:                                      \
     return kExternal##Type##Array;

     TYPED_ARRAYS(ELEMENTS_KIND_TO_ARRAY_TYPE)
 #undef ELEMENTS_KIND_TO_ARRAY_TYPE

     default:
       UNREACHABLE();
   }
 }

 size_t JSTypedArray::element_size() {
   switch (map().elements_kind()) {
 #define ELEMENTS_KIND_TO_ELEMENT_SIZE(Type, type, TYPE, ctype) \
   case TYPE##_ELEMENTS:                                        \
     return sizeof(ctype);

     TYPED_ARRAYS(ELEMENTS_KIND_TO_ELEMENT_SIZE)
 #undef ELEMENTS_KIND_TO_ELEMENT_SIZE

     default:
       UNREACHABLE();
   }
 }

 }  // namespace internal
 }  // namespace v8
	// 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.

	#include "src/objects/js-array-buffer.h"
	#include "src/objects/js-array-buffer-inl.h"

	#include "src/execution/protectors-inl.h"
	#include "src/logging/counters.h"
	#include "src/objects/property-descriptor.h"

	namespace v8 {
	namespace internal {

	namespace {

	bool CanonicalNumericIndexString(Isolate* isolate, Handle<Object> s,
	Handle<Object>* index) {
	DCHECK(s->IsString() \|\| s->IsSmi());

	Handle<Object> result;
	if (s->IsSmi()) {
	result = s;
	} else {
	result = String::ToNumber(isolate, Handle<String>::cast(s));
	if (!result->IsMinusZero()) {
	Handle<String> str = Object::ToString(isolate, result).ToHandleChecked();
	// Avoid treating strings like "2E1" and "20" as the same key.
	if (!str->SameValue(*s)) return false;
	}
	}
	*index = result;
	return true;
	}
	} // anonymous namespace

	void JSArrayBuffer::Setup(SharedFlag shared,
	std::shared_ptr<BackingStore> backing_store) {
	clear_padding();
	set_bit_field(0);
	set_is_shared(shared == SharedFlag::kShared);
	set_is_detachable(shared != SharedFlag::kShared);
	for (int i = 0; i < v8::ArrayBuffer::kEmbedderFieldCount; i++) {
	SetEmbedderField(i, Smi::zero());
	}
	set_extension(nullptr);
	if (!backing_store) {
	set_backing_store(GetIsolate(), nullptr);
	set_byte_length(0);
	} else {
	Attach(std::move(backing_store));
	}
	if (shared == SharedFlag::kShared) {
	GetIsolate()->CountUsage(
	v8::Isolate::UseCounterFeature::kSharedArrayBufferConstructed);
	}
	}

	void JSArrayBuffer::Attach(std::shared_ptr<BackingStore> backing_store) {
	DCHECK_NOT_NULL(backing_store);
	DCHECK_EQ(is_shared(), backing_store->is_shared());
	DCHECK(!was_detached());
	Isolate* isolate = GetIsolate();
	set_backing_store(isolate, backing_store->buffer_start());
	set_byte_length(backing_store->byte_length());
	if (backing_store->is_wasm_memory()) set_is_detachable(false);
	if (!backing_store->free_on_destruct()) set_is_external(true);
	if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
	Heap* heap = isolate->heap();
	ArrayBufferExtension* extension = EnsureExtension();
	size_t bytes = backing_store->PerIsolateAccountingLength();
	extension->set_accounting_length(bytes);
	extension->set_backing_store(std::move(backing_store));
	heap->AppendArrayBufferExtension(*this, extension);
	} else {
	isolate->heap()->RegisterBackingStore(*this, std::move(backing_store));
	}
	}

	void JSArrayBuffer::Detach(bool force_for_wasm_memory) {
	if (was_detached()) return;

	if (force_for_wasm_memory) {
	// Skip the is_detachable() check.
	} else if (!is_detachable()) {
	// Not detachable, do nothing.
	return;
	}

	Isolate* const isolate = GetIsolate();
	if (backing_store()) {
	std::shared_ptr<BackingStore> backing_store;
	if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
	backing_store = RemoveExtension();
	} else {
	backing_store = isolate->heap()->UnregisterBackingStore(*this);
	}
	CHECK_IMPLIES(force_for_wasm_memory, backing_store->is_wasm_memory());
	}

	if (Protectors::IsArrayBufferDetachingIntact(isolate)) {
	Protectors::InvalidateArrayBufferDetaching(isolate);
	}

	DCHECK(!is_shared());
	DCHECK(!is_asmjs_memory());
	set_backing_store(isolate, nullptr);
	set_byte_length(0);
	set_was_detached(true);
	}

	std::shared_ptr<BackingStore> JSArrayBuffer::GetBackingStore() {
	if (V8_ARRAY_BUFFER_EXTENSION_BOOL) {
	if (!extension()) return nullptr;
	return extension()->backing_store();
	} else {
	return GetIsolate()->heap()->LookupBackingStore(*this);
	}
	}

	ArrayBufferExtension* JSArrayBuffer::EnsureExtension() {
	DCHECK(V8_ARRAY_BUFFER_EXTENSION_BOOL);
	ArrayBufferExtension* extension = this->extension();
	if (extension != nullptr) return extension;

	extension = new ArrayBufferExtension(std::shared_ptr<BackingStore>());
	set_extension(extension);
	return extension;
	}

	std::shared_ptr<BackingStore> JSArrayBuffer::RemoveExtension() {
	ArrayBufferExtension* extension = this->extension();
	DCHECK_NOT_NULL(extension);
	auto result = extension->RemoveBackingStore();
	// Remove pointer to extension such that the next GC will free it
	// automatically.
	set_extension(nullptr);
	return result;
	}

	void JSArrayBuffer::MarkExtension() {
	ArrayBufferExtension* extension = this->extension();
	if (extension) {
	extension->Mark();
	}
	}

	void JSArrayBuffer::YoungMarkExtension() {
	ArrayBufferExtension* extension = this->extension();
	if (extension) {
	extension->YoungMark();
	}
	}

	void JSArrayBuffer::YoungMarkExtensionPromoted() {
	ArrayBufferExtension* extension = this->extension();
	if (extension) {
	extension->YoungMarkPromoted();
	}
	}

	Handle<JSArrayBuffer> JSTypedArray::GetBuffer() {
	Isolate* isolate = GetIsolate();
	Handle<JSTypedArray> self(*this, isolate);
	DCHECK(IsTypedArrayElementsKind(self->GetElementsKind()));

	Handle<JSArrayBuffer> array_buffer(JSArrayBuffer::cast(self->buffer()),
	isolate);
	if (!is_on_heap()) {
	// Already is off heap, so return the existing buffer.
	return array_buffer;
	}

	// The existing array buffer should be empty.
	DCHECK_NULL(array_buffer->backing_store());

	// Allocate a new backing store and attach it to the existing array buffer.
	size_t byte_length = self->byte_length();
	auto backing_store =
	BackingStore::Allocate(isolate, byte_length, SharedFlag::kNotShared,
	InitializedFlag::kUninitialized);

	if (!backing_store) {
	isolate->heap()->FatalProcessOutOfMemory("JSTypedArray::GetBuffer");
	}

	// Copy the elements into the backing store of the array buffer.
	if (byte_length > 0) {
	memcpy(backing_store->buffer_start(), self->DataPtr(), byte_length);
	}

	// Attach the backing store to the array buffer.
	array_buffer->Setup(SharedFlag::kNotShared, std::move(backing_store));

	// Clear the elements of the typed array.
	self->set_elements(ReadOnlyRoots(isolate).empty_byte_array());
	self->SetOffHeapDataPtr(isolate, array_buffer->backing_store(), 0);
	DCHECK(!self->is_on_heap());

	return array_buffer;
	}

	// ES#sec-integer-indexed-exotic-objects-defineownproperty-p-desc
	// static
	Maybe<bool> JSTypedArray::DefineOwnProperty(Isolate* isolate,
	Handle<JSTypedArray> o,
	Handle<Object> key,
	PropertyDescriptor* desc,
	Maybe<ShouldThrow> should_throw) {
	// 1. Assert: IsPropertyKey(P) is true.
	DCHECK(key->IsName() \|\| key->IsNumber());
	// 2. Assert: O is an Object that has a [[ViewedArrayBuffer]] internal slot.
	// 3. If Type(P) is String, then
	if (key->IsString() \|\| key->IsSmi()) {
	// 3a. Let numericIndex be ! CanonicalNumericIndexString(P)
	// 3b. If numericIndex is not undefined, then
	Handle<Object> numeric_index;
	if (CanonicalNumericIndexString(isolate, key, &numeric_index)) {
	// 3b i. If IsInteger(numericIndex) is false, return false.
	// 3b ii. If numericIndex = -0, return false.
	// 3b iii. If numericIndex < 0, return false.
	size_t index;
	if (numeric_index->IsMinusZero() \|\|
	!numeric_index->ToIntegerIndex(&index)) {
	RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
	NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
	}
	// 3b iv. Let length be O.[[ArrayLength]].
	size_t length = o->length();
	// 3b v. If numericIndex ≥ length, return false.
	if (o->WasDetached() \|\| index >= length) {
	RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
	NewTypeError(MessageTemplate::kInvalidTypedArrayIndex));
	}
	// 3b vi. If IsAccessorDescriptor(Desc) is true, return false.
	if (PropertyDescriptor::IsAccessorDescriptor(desc)) {
	RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
	NewTypeError(MessageTemplate::kRedefineDisallowed, key));
	}
	// 3b vii. If Desc has a [[Configurable]] field and if
	// Desc.[[Configurable]] is true, return false.
	// 3b viii. If Desc has an [[Enumerable]] field and if Desc.[[Enumerable]]
	// is false, return false.
	// 3b ix. If Desc has a [[Writable]] field and if Desc.[[Writable]] is
	// false, return false.
	if ((desc->has_configurable() && desc->configurable()) \|\|
	(desc->has_enumerable() && !desc->enumerable()) \|\|
	(desc->has_writable() && !desc->writable())) {
	RETURN_FAILURE(isolate, GetShouldThrow(isolate, should_throw),
	NewTypeError(MessageTemplate::kRedefineDisallowed, key));
	}
	// 3b x. If Desc has a [[Value]] field, then
	// 3b x 1. Let value be Desc.[[Value]].
	// 3b x 2. Return ? IntegerIndexedElementSet(O, numericIndex, value).
	if (desc->has_value()) {
	if (!desc->has_configurable()) desc->set_configurable(false);
	if (!desc->has_enumerable()) desc->set_enumerable(true);
	if (!desc->has_writable()) desc->set_writable(true);
	Handle<Object> value = desc->value();
	LookupIterator it(isolate, o, index, LookupIterator::OWN);
	RETURN_ON_EXCEPTION_VALUE(
	isolate,
	DefineOwnPropertyIgnoreAttributes(&it, value, desc->ToAttributes()),
	Nothing<bool>());
	}
	// 3b xi. Return true.
	return Just(true);
	}
	}
	// 4. Return ! OrdinaryDefineOwnProperty(O, P, Desc).
	return OrdinaryDefineOwnProperty(isolate, o, key, desc, should_throw);
	}

	ExternalArrayType JSTypedArray::type() {
	switch (map().elements_kind()) {
	#define ELEMENTS_KIND_TO_ARRAY_TYPE(Type, type, TYPE, ctype) \
	case TYPE##_ELEMENTS: \
	return kExternal##Type##Array;

	TYPED_ARRAYS(ELEMENTS_KIND_TO_ARRAY_TYPE)
	#undef ELEMENTS_KIND_TO_ARRAY_TYPE

	default:
	UNREACHABLE();
	}
	}

	size_t JSTypedArray::element_size() {
	switch (map().elements_kind()) {
	#define ELEMENTS_KIND_TO_ELEMENT_SIZE(Type, type, TYPE, ctype) \
	case TYPE##_ELEMENTS: \
	return sizeof(ctype);

	TYPED_ARRAYS(ELEMENTS_KIND_TO_ELEMENT_SIZE)
	#undef ELEMENTS_KIND_TO_ELEMENT_SIZE

	default:
	UNREACHABLE();
	}
	}

	} // namespace internal
	} // namespace v8