tree fc86f4153a1cde09315909fd2e5606df479a5d85
parent 92be6f4430fec6734b7bee7de23523508cb859bf
author Wyatt Hepler <hepler@google.com> 1655146230 -0700
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> 1655411226 +0000

pw_span: Introduce pw::span

- pw::span is identical to Pigweed's polyfilled std::span, but in a
  different namespace. Implicit converions between std::span and
  pw::span are supported inherently.

  pw::span and std::span are maintained as separate classes, with shared
  code in a .inc file. This is done instead of aliasing since C++17 does
  not support class template argument decuction with aliases. Also, it
  is simpler to have separate implementations to avoid circular
  dependencies while migrating code to pw::span.
- Add DEFINES to the pw_add_test() CMake function to support defining
  preprocessor macros for the pw_span test.
- Move '.inc' and '.inl' extensions from CPP_HEADER_EXTS to
  CPP_SOURCE_EXTS, since these should be treated like sources not
  headers (no include guards).

Bug: b/235237667
Change-Id: I4d76fb373cdaa4d3a5d72a0537bea492b5c06814
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/98160
Commit-Queue: Wyatt Hepler <hepler@google.com>
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Reviewed-by: Ted Pudlik <tpudlik@google.com>