Predeclare enums in base.h

Including ssl.h is quite a chunk of code and #defines, so we've tried to
limit its spread internally in the interests of code hygine given that
we have a multi-billion-line repo.

However, header files that mention enums from ssl.h currently need to
include ssl.h. For example, your class may have static class member
functions intended to be callbacks, and they need to be class members
because they'll call other private methods.

C cannot predeclare enums, but C++ can if you explicitly type them.
Sadly C doesn't support explicit types. So option one is to move the
enums into base.h. That works, but the enums properly live in ssl.h and
reading the header file is a lot clearer if you don't have to jump
around to see all the pieces.

So option two (this change) is to explicitly type and predelcare the
enums in base.h for C++ only. The worry now is that C and C++ might
disagree about the type of the enums. However, this has already
happened: at least for |ssl_private_key_result_t|, g++ thinks that it's
an |int| (without any explicit type) and gcc thinks that it's an
|unsigned|. At least they're the same length, I guess?

So, to make sure that this doesn't slip any more, this change also adds
|ssl_test_c.c| which tests that C views the enums as having the same
size as an |int|, at least.

Change-Id: I8248583ec997021f8226d5a798609f6afc96dac4
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35664
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
5 files changed
tree: 493c1837b51458408661edef6492c38203cb881a
  1. .clang-format
  2. .github/
  3. .gitignore
  4. API-CONVENTIONS.md
  5. BREAKING-CHANGES.md
  6. BUILDING.md
  7. CMakeLists.txt
  8. CONTRIBUTING.md
  9. FUZZING.md
  10. INCORPORATING.md
  11. LICENSE
  12. PORTING.md
  13. README.md
  14. STYLE.md
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fipstools/
  19. fuzz/
  20. go.mod
  21. include/
  22. sources.cmake
  23. ssl/
  24. third_party/
  25. tool/
  26. util/
README.md

BoringSSL

BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

There are other files in this directory which might be helpful: