Add Dart_ListGetRange

Add Dart_ListGetRange

This API lets you get multiple values out of a list at once, saving overhead.

R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/bc88578fe174c6e1f8485cefe888b5e3bfc45895

[abarth-chromium, 2015-08-11 20:37:54]

abarth@chromium.org changed reviewers:
+ sivaa@google.com

[abarth-chromium, 2015-08-11 20:38:35]

Are there try jobs I should run?  I didn't manage to compile the tests...

[abarth-chromium, 2015-08-12 15:58:45]

abarth@chromium.org changed reviewers:
+ asiva@google.com
- sivaa@google.com

[siva, 2015-08-12 17:07:25]

LGTM with one comment.

https://codereview.chromium.org/1284633004/diff/20001/runtime/include/dart_api.h
File runtime/include/dart_api.h (right):

https://codereview.chromium.org/1284633004/diff/20001/runtime/include/dart_ap...
runtime/include/dart_api.h:1846: * If the any of the requested index values are
out of bounds, an error occurs.
If any of the requested ...

https://codereview.chromium.org/1284633004/diff/20001/runtime/include/dart_ap...
runtime/include/dart_api.h:1855: * \return A valid handle if no error occurs
during the operation.
return Success if no error ....

https://codereview.chromium.org/1284633004/diff/20001/runtime/vm/dart_api_imp...
File runtime/vm/dart_api_impl.cc (right):

https://codereview.chromium.org/1284633004/diff/20001/runtime/vm/dart_api_imp...
runtime/vm/dart_api_impl.cc:2741: result[index] = Api::NewHandle(isolate,
array_obj.At(index + offset));   \
We normally use { ... } even if there is only one statement in the block.

https://codereview.chromium.org/1284633004/diff/20001/runtime/vm/dart_api_imp...
runtime/vm/dart_api_impl.cc:2744: return Api::NewError("Invalid index passed in
to access list element");      \
Invalid offset/index passed.....

https://codereview.chromium.org/1284633004/diff/20001/runtime/vm/dart_api_imp...
runtime/vm/dart_api_impl.cc:2752: DARTSCOPE(isolate);
if (result == NULL) {
  RETURN_NULL_ERROR(result);
}

https://codereview.chromium.org/1284633004/diff/20001/runtime/vm/dart_api_imp...
runtime/vm/dart_api_impl.cc:2770: Instance::Handle(isolate,
Integer::New(index))));
This would be a little more optimal if we did not use Send1Arg in the loop.
Send1Arg resolves the function '[]' and we could hoist that out of the loop.

Something like:
  const intptr_t kNumArgs = 2;
  ArgumentsDescriptor args_desc(
      Array::Handle(ArgumentsDescriptor::New(kNumArgs)));
  const Function& function = Function::Handle(
      Resolver::ResolveDynamic(receiver, selector, args_desc));
  if (function.IsNull()) {
    return ApiError::New(String::Handle(String::New("")));
  }
  const Array& args = Array::Handle(Array::New(kNumArgs));
  args.SetAt(0, receiver);
  Instance& index = Instance::Handle(isolate);
  for (intptr_t index = 0; index < length; ++index) {
    index = Integer::New(index);
    args.SetAt(1, index);
    Dart_Handle value =
        Api::NewHandle(isolate,
                       DartEntry::InvokeFunction(function, args));
    ...
    ...
  }

[abarth-chromium, 2015-08-12 22:28:01]

Addressed view comments and managed to run the tests locally.

[abarth-chromium, 2015-08-12 22:28:05]

The CQ bit was checked by abarth@chromium.org

[abarth-chromium, 2015-08-12 22:28:06]

The patchset sent to the CQ was uploaded after l-g-t-m from asiva@google.com
Link to the patchset: https://codereview.chromium.org/1284633004/#ps40001
(title: "Address review comments")

[commit-bot: I haz the power, 2015-08-12 22:30:02]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-12 22:30:03]

Commit queue rejected this change because it did not recognize the base URL.
Please commit your change manually.

[abarth-chromium, 2015-08-12 23:46:42]

Committed patchset #3 (id:40001) manually as
bc88578fe174c6e1f8485cefe888b5e3bfc45895 (presubmit successful).