[ARROW-15373] [C++] MemoryManager::AllocateBuffer should return unique_ptr

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/30857
• Assignee: David Li
• Reporter: David Li
• Created: 19/Jan/22 19:31
• Updated: 11/Jan/23 11:36
• Resolved: 24/Jan/22 13:01

Description

MemoryManager::AllocateBuffer currently returns shared_ptr<Buffer>, but analogously to arrow::AllocateBuffer, it should probably return unique_ptr<Buffer>. Also, we can convert a unique_ptr to a shared_ptr but not the other way around.

This would be a breaking change in a core API, though. I think this API is not used much, given it is relatively new, but we should keep this in mind.

(Context: for the Flight/UCX prototype, I'm trying to integrate MemoryManager support given UCX can transparently handle some types of non-CPU memory, but while I've used mostly unique_ptr so far, MemoryManager uses shared_ptr which did cause a small snag.)

Issue Links

• causes: ARROW-15424 [C++][GLib] Update bindings for MemoryManager::AllocateBuffer
• is related to: ARROW-15579 [C++] Add MemoryManager::CopyBuffer(Buffer&)
• links to: GitHub Pull Request #12192