[dave-365]

Fixes #1747

Description

This PR introduces C++20 std::span overloads for buffer-like types (Buffer<T>, ArrayBuffer, and TypedArrayOf<T>), allowing developers to pass bounds-carrying handles directly without manually managing separate raw pointers and length parameters:

• Added Buffer<T>::New, Buffer<T>::NewOrCopy, and Buffer<T>::Copy overloads accepting std::span.
• Added ArrayBuffer::New overloads accepting std::span.
• Added .Span() accessors to Buffer<T>, ArrayBuffer, and TypedArrayOf<T>.
• All std::span APIs are conditionally compiled under #if defined(__cpp_lib_span).
• Completely preserves ABI compatibility and backward compatibility for C++ < 20.
• Added comprehensive unit tests in test/buffer.cc and test/array_buffer.cc.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.75%. Comparing base (25c6b21) to head (1803c34).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1760      +/-   ##
==========================================
+ Coverage   63.68%   63.75%   +0.07%     
==========================================
  Files           3        3              
  Lines        2065     2072       +7     
  Branches      731      733       +2     
==========================================
+ Hits         1315     1321       +6     
  Misses        162      162              
- Partials      588      589       +1     

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[KevinEady]

Hi @dave-365 ,

Can you rebase on main and then I'll re-run the CI. Thanks!

[dave-365]

Hi @dave-365 ,

Can you rebase on main and then I'll re-run the CI. Thanks!

I did rebase and pushed can you try now.

[dave-365]

@KevinEady can you proceed workflow run.

[dave-365]

@KevinEady I have did rebased can just approve for workflow run check.

[KevinEady]

Mostly documentation issues.

Also: was there a reason SharedArrayBuffer was not included in your changes?

[legendecas]

I don't think spans shall be used to represent external array buffers. Spans do not represent ownership and an external array buffer means the caller owns the external data.

I'd prefer only keeping the Copy methods for spans.

[dave-365]

Mostly documentation issues.

Also: was there a reason SharedArrayBuffer was not included in your changes?

Hi @KevinEady,

Thanks for pointing that out!

1. SharedArrayBuffer: It was initially an oversight. I have now included SharedArrayBuffer::Span() returning std::span<uint8_t> Span() const in napi.h and napi-inl.h, along with its documentation in doc/shared_array_buffer.md.
2. Documentation: All Markdown documentation has been added across:
   • doc/buffer.md (New, NewOrCopy, Copy, Span)
   • doc/array_buffer.md (New, Span)
   • doc/shared_array_buffer.md (Span)
   • doc/typed_array_of.md (Span)
3. Per @legendecas's suggestion, ArrayBuffer::Span() and SharedArrayBuffer::Span() have also been updated to return std::span<uint8_t> Span() const; representing raw memory blocks.