Reviewers: Dmitry Lomov (chromium), Ken Russell,
Description:
Expose ArrayBufferView::HasBuffer
This allows the embedder to decide whether it's worthwhile to copy the
contents to avoid materializing a buffer.
BUG=v8:3996
[email protected],[email protected]
LOG=y
Please review this at https://codereview.chromium.org/1084513002/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+20, -13 lines):
M include/v8.h
M src/api.cc
M test/cctest/test-typedarrays.cc
Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index
d94e9b32b854826ba221abb3948f057fb74a9a26..908c0e19e36c206915cc596bbdc5daa691c32c17
100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -3511,6 +3511,15 @@ class V8_EXPORT ArrayBufferView : public Object {
*/
size_t CopyContents(void* dest, size_t byte_length);
+ /**
+ * Returns true if ArrayBufferView::Buffer() is a no-op. If it returns
false,
+ * getting the buffer might incur allocating a backing store and
materializing
+ * the contents. In that case, CopyContents can be used to access the
+ * underlying contents of this ArrayBufferView without materializing the
+ * buffer first.
+ */
+ bool HasBuffer() const;
+
V8_INLINE static ArrayBufferView* Cast(Value* obj);
static const int kInternalFieldCount =
Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index
733214ec076712b31538853fe24fcc03162f80b9..9d4356c5140777598b0c67ebc3d293fc3bcacc37
100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6471,6 +6471,15 @@ size_t v8::ArrayBufferView::CopyContents(void* dest,
size_t byte_length) {
}
+bool v8::ArrayBufferView::HasBuffer() const {
+ i::Handle<i::JSArrayBufferView> obj = Utils::OpenHandle(this);
+ if (obj->IsJSDataView()) return true;
+ DCHECK(obj->IsJSTypedArray());
+ i::Handle<i::JSTypedArray> typed_array(i::JSTypedArray::cast(*obj));
+ return !typed_array->buffer()->IsSmi();
+}
+
+
size_t v8::ArrayBufferView::ByteOffset() {
i::Handle<i::JSArrayBufferView> obj = Utils::OpenHandle(this);
return static_cast<size_t>(obj->byte_offset()->Number());
Index: test/cctest/test-typedarrays.cc
diff --git a/test/cctest/test-typedarrays.cc
b/test/cctest/test-typedarrays.cc
index
dc1bca2e0a241b4e4d02e92f2a783e4793b92591..966edb720ee5b7c03b97e3d2e919209505558f0d
100644
--- a/test/cctest/test-typedarrays.cc
+++ b/test/cctest/test-typedarrays.cc
@@ -19,22 +19,11 @@ void TestArrayBufferViewContents(LocalContext& env,
bool should_use_buffer) {
CHECK(obj_a->IsArrayBufferView());
v8::Local<v8::ArrayBufferView> array_buffer_view =
v8::Local<v8::ArrayBufferView>::Cast(obj_a);
- Handle<JSArrayBufferView> internal_view(
- v8::Utils::OpenHandle(*array_buffer_view));
- bool has_buffer = true;
- if (internal_view->IsJSTypedArray()) {
- Handle<JSTypedArray> typed_array(JSTypedArray::cast(*internal_view));
- has_buffer = !typed_array->buffer()->IsSmi();
- }
- CHECK_EQ(has_buffer, should_use_buffer);
+ CHECK_EQ(array_buffer_view->HasBuffer(), should_use_buffer);
unsigned char contents[4] = {23, 23, 23, 23};
CHECK_EQ(sizeof(contents),
array_buffer_view->CopyContents(contents, sizeof(contents)));
- if (!has_buffer) {
- CHECK(internal_view->IsJSTypedArray());
- Handle<JSTypedArray> typed_array(JSTypedArray::cast(*internal_view));
- CHECK(typed_array->buffer()->IsSmi());
- }
+ CHECK_EQ(array_buffer_view->HasBuffer(), should_use_buffer);
for (size_t i = 0; i < sizeof(contents); ++i) {
CHECK_EQ(i, contents[i]);
}
--
--
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