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Posted to dev@arrow.apache.org by Krisztián Szűcs <sz...@gmail.com> on 2018/06/01 09:40:30 UTC
[C++] Avoiding Nullptrs?
Hi Everyone,
Recently I've investigated a parquet edge case ARROW-2591 which is caused by a returned nullptr here. (https://link.getmailspring.com/link/1527842287.local-dc8ae776-35fa-v1.2.2-96fb3a99@getmailspring.com/0?redirect=https%3A%2F%2Fgithub.com%2Fapache%2Fparquet-cpp%2Fblob%2Fmaster%2Fsrc%2Fparquet%2Farrow%2Fwriter.cc%23L415&recipient=ZGV2QGFycm93LmFwYWNoZS5vcmc%3D)
I'm wondering would it be possible to avoid having nullptrs instead of checking them?
IMHO having them around causes hidden bugs as well as increases the complexity.
Krisztian
Re: [C++] Avoiding Nullptrs?
Posted by Wes McKinney <we...@gmail.com>.
hi Krisztian,
This is a tricky problem. This has come up in other circumstances as I
recall, I can't remember specifically where.
In the case of Buffers, we could possibly avoid having a
shared_ptr<Buffer>(nullptr) issue by creating a "dummy" zero-length
buffer with a valid memory address for its data. This wouldn't prevent
the case where some code has created a Buffer(nullptr, 0) elsewhere
(so an instance of Buffer has been allocated, but its internal data_
member is null).
One way to alleviate the pain (without adding code to ensure that
either a buffer or its data_ member is never null) might be to have
some helper methods like
https://github.com/apache/arrow/blob/master/cpp/src/arrow/compute/kernels/util-internal.h#L33
though I think this function needs a nullptr check also (just created
https://issues.apache.org/jira/browse/ARROW-2708 to look into it)
- Wes
On Fri, Jun 1, 2018 at 5:40 AM, Krisztián Szűcs
<sz...@gmail.com> wrote:
> Hi Everyone,
>
> Recently I've investigated a parquet edge case ARROW-2591 which is caused by a returned nullptr here. (https://link.getmailspring.com/link/1527842287.local-dc8ae776-35fa-v1.2.2-96fb3a99@getmailspring.com/0?redirect=https%3A%2F%2Fgithub.com%2Fapache%2Fparquet-cpp%2Fblob%2Fmaster%2Fsrc%2Fparquet%2Farrow%2Fwriter.cc%23L415&recipient=ZGV2QGFycm93LmFwYWNoZS5vcmc%3D)
> I'm wondering would it be possible to avoid having nullptrs instead of checking them?
> IMHO having them around causes hidden bugs as well as increases the complexity.
>
> Krisztian