Checks for valid CObject lengths in native API.

Checks CObject lengths in native API.

Also converts the API to use intptr_t instead of a mixture of int64_t and int. Internally all variable length objects have lengths and maximum values represented as intptr_t (actually Smi ranges). In order to check for these maximum lengths we need to have a common type for 32 and 64 bit platforms.

Helping constructs like IOBuffer can still use 64bit lengths, but have to check that there values are actually in the domain of intptr_t as soon as internal objects are created.

Addresses issue 4314.

BUG=
R=asiva@google.com, sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=27395

[Michael Lippautz (Google), 2013-09-09 19:45:53]

Includes changes from https://codereview.chromium.org/23479010/

Previously the length attribute of CObject was int and set from one of the
following type/location combinations:
* intptr_t: AsyncDirectoryListing; not correct on x64
* int: all the ::New* "constructors" in dartutils.h/.cc
* int64_t: NewExternalUint8Array, NewIOBuffer; not correct on ia32

Changed the API to use intptr_t exclusively, as we internally also use a value
in the domain of intptr_t (few bits less) as maximum length.

[siva, 2013-09-09 22:49:57]

In your CL comments can you elaborate on the need
for this conversion :

"Also converts the API to use intptr_t instead of a mixture of int64_t and int"

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/file.cc
File runtime/bin/file.cc (right):

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/file.cc#newcod...
runtime/bin/file.cc:953: Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
ASSERT here too?

[siva, 2013-09-09 22:56:58]

lgtm

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/dartutils.cc
File runtime/bin/dartutils.cc (right):

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/dartutils.cc#n...
runtime/bin/dartutils.cc:972: if (length > kIntptrMax) {
I thought you were going to check against kSmiMax but I guess that value is not
available here.

[Michael Lippautz (Google), 2013-09-09 23:14:40]

Updated CL description and addressed comments.

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/dartutils.cc
File runtime/bin/dartutils.cc (right):

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/dartutils.cc#n...
runtime/bin/dartutils.cc:972: if (length > kIntptrMax) {
On 2013/09/09 22:56:58, siva wrote:
> I thought you were going to check against kSmiMax but I guess that value is
not
> available here.
> 

Yep, neither kSmiMax, nor ExternalTypedData::MaxElements() are available here.
So this is just checking for the domain and relying on the writer to do the
check against max elements. (which it does)

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/file.cc
File runtime/bin/file.cc (right):

https://codereview.chromium.org/23532048/diff/4001/runtime/bin/file.cc#newcod...
runtime/bin/file.cc:953: Dart_CObject* io_buffer = CObject::NewIOBuffer(length);
On 2013/09/09 22:49:57, siva wrote:
> ASSERT here too?

Done.

[Søren Gjesse, 2013-09-11 07:23:03]

lgtm

[Michael Lippautz (Google), 2013-09-11 16:57:06]

Committed patchset #3 manually as r27395 (presubmit successful).