Support posting of external data into dart as external uint8 arrays through the Dart API.

Support posting of external data into dart as external uint8 arrays through the Dart API.

The native ports use the snapshot reader to create the dart objects. Added support for reading external arrays from snapshots but no support for writing them. The only way an external array is written to a snapshot is through the api message writer.

This allows dart:io to avoid one copy of data read from files and sockets. This change only contains one use of the new API.

R=asiva@google.com,iposva@google.com
BUG=
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=9281

[siva, 2012-06-28 16:44:05]

LGTM,

We could add the notion of restricting post of these messages to any external
process in a different CL.

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/bin/dartutils.h
File runtime/bin/dartutils.h (right):

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/bin/dartutils....
runtime/bin/dartutils.h:322: }
DISALLOW_COPY_AND_ASSIGN(...);

Seems to be missing in all the classes in this file, not sure why.

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/vm/dart_api_me...
File runtime/vm/dart_api_message.cc (right):

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/vm/dart_api_me...
runtime/vm/dart_api_message.cc:731:
WriteIntptrValue(reinterpret_cast<intptr_t>(callback));
As discussed offline we need some mechanism to ensure that this message is not
posted to an external process. maybe you could add a TODO here to that effect.

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/vm/raw_object_...
File runtime/vm/raw_object_snapshot.cc (right):

https://chromiumcodereview.appspot.com/10698011/diff/1/runtime/vm/raw_object_...
runtime/vm/raw_object_snapshot.cc:1812: Snapshot::Kind kind) {                  
                                  \
ASSERT(kind != Snapshot::kFull);
or
if (kind == Snapshot::kFull) {
  UNREACHABLE();
}

[Mads Ager (google), 2012-06-28 18:06:51]

Thanks Siva!

http://codereview.chromium.org/10698011/diff/1/runtime/bin/dartutils.h
File runtime/bin/dartutils.h (right):

http://codereview.chromium.org/10698011/diff/1/runtime/bin/dartutils.h#newcod...
runtime/bin/dartutils.h:322: }
On 2012/06/28 16:44:05, asiva wrote:
> DISALLOW_COPY_AND_ASSIGN(...);
> 
> Seems to be missing in all the classes in this file, not sure why.

Me neither, but they are there now. Thanks. :)

http://codereview.chromium.org/10698011/diff/1/runtime/vm/dart_api_message.cc
File runtime/vm/dart_api_message.cc (right):

http://codereview.chromium.org/10698011/diff/1/runtime/vm/dart_api_message.cc...
runtime/vm/dart_api_message.cc:731:
WriteIntptrValue(reinterpret_cast<intptr_t>(callback));
On 2012/06/28 16:44:05, asiva wrote:
> As discussed offline we need some mechanism to ensure that this message is not
> posted to an external process. maybe you could add a TODO here to that effect.

Done.

http://codereview.chromium.org/10698011/diff/1/runtime/vm/raw_object_snapshot.cc
File runtime/vm/raw_object_snapshot.cc (right):

http://codereview.chromium.org/10698011/diff/1/runtime/vm/raw_object_snapshot...
runtime/vm/raw_object_snapshot.cc:1812: Snapshot::Kind kind) {                  
                                  \
On 2012/06/28 16:44:05, asiva wrote:
> ASSERT(kind != Snapshot::kFull);
> or
> if (kind == Snapshot::kFull) {
>   UNREACHABLE();
> }

Added the ASSERT. Thanks!

[Mads Ager (google), 2012-07-02 07:24:02]

Ivan, I landed the changelist. I will address any comments you might have as a
separate changelist.

On 2012/06/28 18:06:51, Mads Ager wrote:
> Thanks Siva!
> 
> http://codereview.chromium.org/10698011/diff/1/runtime/bin/dartutils.h
> File runtime/bin/dartutils.h (right):
> 
>
http://codereview.chromium.org/10698011/diff/1/runtime/bin/dartutils.h#newcod...
> runtime/bin/dartutils.h:322: }
> On 2012/06/28 16:44:05, asiva wrote:
> > DISALLOW_COPY_AND_ASSIGN(...);
> > 
> > Seems to be missing in all the classes in this file, not sure why.
> 
> Me neither, but they are there now. Thanks. :)
> 
> http://codereview.chromium.org/10698011/diff/1/runtime/vm/dart_api_message.cc
> File runtime/vm/dart_api_message.cc (right):
> 
>
http://codereview.chromium.org/10698011/diff/1/runtime/vm/dart_api_message.cc...
> runtime/vm/dart_api_message.cc:731:
> WriteIntptrValue(reinterpret_cast<intptr_t>(callback));
> On 2012/06/28 16:44:05, asiva wrote:
> > As discussed offline we need some mechanism to ensure that this message is
not
> > posted to an external process. maybe you could add a TODO here to that
effect.
> 
> Done.
> 
>
http://codereview.chromium.org/10698011/diff/1/runtime/vm/raw_object_snapshot.cc
> File runtime/vm/raw_object_snapshot.cc (right):
> 
>
http://codereview.chromium.org/10698011/diff/1/runtime/vm/raw_object_snapshot...
> runtime/vm/raw_object_snapshot.cc:1812: Snapshot::Kind kind) {                
 
>                                   \
> On 2012/06/28 16:44:05, asiva wrote:
> > ASSERT(kind != Snapshot::kFull);
> > or
> > if (kind == Snapshot::kFull) {
> >   UNREACHABLE();
> > }
> 
> Added the ASSERT. Thanks!