Add support for typed data views on native threads

Add support for typed data views on native threads

The deserializer running outside the VM can now decode typed data
views. As the typed data views are implemented as normal Dart
instances and not a internal VM object the deserializer have been
expanded to process serialized objects of the type used to create
these views. The typed data object that the view is based on will
always be serialized as part of the message.

Currently only vews created with constructor Uint8List.view on top of
an Uint8List are supported.

R=ager@google.com

BUG=https://code.google.com/p/dart/issues/detail?id=9484

Committed: https://code.google.com/p/dart/source/detail?r=21252

[Mads Ager (google), 2013-04-11 05:57:04]

LGTM

https://codereview.chromium.org/14065006/diff/1/runtime/vm/dart_api_message.h
File runtime/vm/dart_api_message.h (right):

https://codereview.chromium.org/14065006/diff/1/runtime/vm/dart_api_message.h...
runtime/vm/dart_api_message.h:17: // TODO(sjesse): Remove this when message
serialization format is
Update this TODO with a bug report with more information about the proposed
changes to the message serialization format? Or maybe just remove the TODO?

https://codereview.chromium.org/14065006/diff/1/tests/standalone/io/file_type...
File tests/standalone/io/file_typed_data_test.dart (right):

https://codereview.chromium.org/14065006/diff/1/tests/standalone/io/file_type...
tests/standalone/io/file_typed_data_test.dart:31: temp.deleteSync(recursive:
true);
Maybe add a keep-alive port so we time-out if one of the async operations does
not complete?

[Søren Gjesse, 2013-04-11 06:47:27]

https://codereview.chromium.org/14065006/diff/1/runtime/vm/dart_api_message.h
File runtime/vm/dart_api_message.h (right):

https://codereview.chromium.org/14065006/diff/1/runtime/vm/dart_api_message.h...
runtime/vm/dart_api_message.h:17: // TODO(sjesse): Remove this when message
serialization format is
On 2013/04/11 05:57:04, Mads Ager wrote:
> Update this TODO with a bug report with more information about the proposed
> changes to the message serialization format? Or maybe just remove the TODO?

I removed the TODO. At some point there where rumors that serialization for
messages should be simpler than snapshot serialization. I am not sure where that
stands at the moment. For now we need this even more to read views.

https://codereview.chromium.org/14065006/diff/1/tests/standalone/io/file_type...
File tests/standalone/io/file_typed_data_test.dart (right):

https://codereview.chromium.org/14065006/diff/1/tests/standalone/io/file_type...
tests/standalone/io/file_typed_data_test.dart:31: temp.deleteSync(recursive:
true);
On 2013/04/11 05:57:04, Mads Ager wrote:
> Maybe add a keep-alive port so we time-out if one of the async operations does
> not complete?

Done.

[Søren Gjesse, 2013-04-11 07:15:20]

Committed patchset #2 manually as r21252.

[siva, 2013-04-15 20:17:47]

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
File runtime/vm/dart_api_message.cc (right):

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:225: strncmp("_Uint8ArrayView", class_name, 15)
== 0) {
This seems rather inefficient having to do a strcmp to identify the class id
every time.
I am wondering if we should change the writing of TypedData View objects in the
snapshot to be similar to regular TypedData objects (i.e explicitly write out
the class id etc.)

That way reading it back will also be easy.

[siva, 2013-04-15 20:26:30]

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
File runtime/vm/dart_api_message.cc (right):

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:239: // Now turn the view into a byte array.
Another issue that might need addressing :

if we send an array of typed data view objects and all these typed data view
objects are views to the same typed data object then this scheme of converting
the view to a typed data may not quite work.

[Søren Gjesse, 2013-04-17 12:54:58]

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
File runtime/vm/dart_api_message.cc (right):

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:225: strncmp("_Uint8ArrayView", class_name, 15)
== 0) {
On 2013/04/15 20:17:47, siva wrote:
> This seems rather inefficient having to do a strcmp to identify the class id
> every time.
> I am wondering if we should change the writing of TypedData View objects in
the
> snapshot to be similar to regular TypedData objects (i.e explicitly write out
> the class id etc.)
> 
> That way reading it back will also be easy.

That would be a great idea. I added this way of processing a Dart instance as a
temporary solution. There are already specific Cid's for these classes
(kTypedDataUint8ArrayViewCid etc.) - are these already assigned to these
instances?

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:239: // Now turn the view into a byte array.
On 2013/04/15 20:26:30, siva wrote:
> Another issue that might need addressing :
> 
> if we send an array of typed data view objects and all these typed data view
> objects are views to the same typed data object then this scheme of converting
> the view to a typed data may not quite work.

Why is that? The view will just point to the underlying deserialized data. Some
of the tests added in  https://codereview.chromium.org/14200031 should show
this.

[siva, 2013-04-18 02:30:40]

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
File runtime/vm/dart_api_message.cc (right):

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:225: strncmp("_Uint8ArrayView", class_name, 15)
== 0) {
Yes these predefined Cid's are already assigned to these instances (look for the
macro REGISTER_TYPED_DATA_VIEW_CLASS in object.cc).

On 2013/04/17 12:54:58, Søren Gjesse wrote:
> On 2013/04/15 20:17:47, siva wrote:
> > This seems rather inefficient having to do a strcmp to identify the class id
> > every time.
> > I am wondering if we should change the writing of TypedData View objects in
> the
> > snapshot to be similar to regular TypedData objects (i.e explicitly write
out
> > the class id etc.)
> > 
> > That way reading it back will also be easy.
> 
> That would be a great idea. I added this way of processing a Dart instance as
a
> temporary solution. There are already specific Cid's for these classes
> (kTypedDataUint8ArrayViewCid etc.) - are these already assigned to these
> instances?

https://codereview.chromium.org/14065006/diff/6001/runtime/vm/dart_api_messag...
runtime/vm/dart_api_message.cc:239: // Now turn the view into a byte array.
On 2013/04/17 12:54:58, Søren Gjesse wrote:
> On 2013/04/15 20:26:30, siva wrote:
> > Another issue that might need addressing :
> > 
> > if we send an array of typed data view objects and all these typed data view
> > objects are views to the same typed data object then this scheme of
converting
> > the view to a typed data may not quite work.
> 
> Why is that? The view will just point to the underlying deserialized data.
Some
> of the tests added in  https://codereview.chromium.org/14200031 should show
> this.

True it would point to the underlying deserialized data but we have now
converted it into a kUint8Array which means it is a regular byte array and
should not share the data with the other view objects which were also converted
into kUint8Array types.

Maybe I am not quite understanding why you need to change the type to
kUint8Array instead of just leaving it as a kView.