Summary:
[Folly] Style tweaks to `max_align_v` calculation.

* Change ns from `folly::detail` since that can be crowded and many other folly libraries may include this header.
* Extract a 2-param `max` alias.
* Fix an incorrectly hardcoded `size_t`.

Reviewed By: WillerZ

Differential Revision: D5468758

fbshipit-source-id: 14a3f67323020a3cfce2b3b46f5f64f3e6125027

Summary: [Folly] Apply `clang-format` to `folly/tracing/`.

Reviewed By: Orvid

Differential Revision: D5460511

fbshipit-source-id: c7a7d34211044a1b76934f184a8552a96d0bad91

Summary: [Folly] Parse suffixes without switch-fallthrough in huge-pages. It is clever, but weird. We can use an immediately-executed lambda expression to make it convenient.

Reviewed By: Orvid

Differential Revision: D5467585

fbshipit-source-id: 02ddb97641db97e38e3f40388ecc522eccd436cb

Summary: [Folly] Apply `clang-format` to `folly/experimental/bser/`.

Reviewed By: Orvid

Differential Revision: D5460552

fbshipit-source-id: e103f8920eb29b7c14688f5bbb3e28129ef35e96

Summary: [Folly] Drop a remnant of gcc48 support in futures. Because gcc48 is no longer supported.

Reviewed By: Orvid, meyering

Differential Revision: D5460788

fbshipit-source-id: 86e2985a0980357641d18f59fd25b9667ec30ab0

Summary:
Fix comment for exception_wrapper's `operator bool()`.
It reads "return `true` if `*this` is not holding an exception"
but the actual behavior is to return `true` if `*this` *is* holding
an exception.

Reviewed By: yfeldblum

Differential Revision: D5456386

fbshipit-source-id: ec3a472ea441476d835881e94036a3957bb2ab32

Summary:
`folly::max_align_t` is a portable replacement for `std::max_align_t`.

`folly::max_align_v` is a `constexpr size_t` with the same value as `alignof(folly::max_align_t)`

32-bit iOS environments have `alignof(std::max_align_t) == 4`, which is not correct. This is more
correct in that I have not yet found a more-aligned basic type.

Reviewed By: yfeldblum

Differential Revision: D5442333

fbshipit-source-id: 0a93e48a730d65ef76e04f132b5976c93587b14c

Summary:
Add non null annotation to
folly to help with linters
complaining when a pointer could
be null, however it never is.

Reviewed By: yfeldblum

Differential Revision: D5453255

fbshipit-source-id: cf7ccbcc86d171ef4f6d373b6f751f709e4587b1

Summary:
[Folly] Move futures helper types into `folly::futures::detail`.

From `folly::detail`, where it would be easier to collide. Especially for names like `Core`.

Reviewed By: WillerZ

Differential Revision: D5460766

fbshipit-source-id: 3f7bff784bbb89c7c86d2f1824323d71321c7ad6

Summary: It is possible in certain cirucmstances for the cxxabi reflection code in `ExceptionTracer` to fail to cope with exceptions that we've seen in production and it currently aborts the process in that case. This diff switches this to `DFATAL`/`DCHECK`.

Reviewed By: yfeldblum

Differential Revision: D5431445

fbshipit-source-id: c3d68372c2fadbb518f78fe99e817db611953d22

Summary: The pattern `mapped([](auto&& i) { ...; return std::move(i); }` is quite common. Evidently people need some good mechanism to just observe or possibly mutate items in pipelines. Note that this is still lazy, it is only called when the pipeline is run.

Reviewed By: yfeldblum

Differential Revision: D5457196

fbshipit-source-id: 3a892b8895e02dd8fcd6a7fd4d3b27063d1b071f

Summary:
Currently gcc does not support attributes declared using square brackets well and some builds might break because of this.

Since `__attribute__((...))` works for both clang and gcc, we should switch to it for now.

Reviewed By: yfeldblum

Differential Revision: D5456734

fbshipit-source-id: d7a8bf1389afc5d60604f22d37c93611dc46259c

Summary: Current folly version uses a single crc32c.  crc32c has a latency of 3, so pipelining three in a row makes it nearly 3x faster (for data all in cache).

Reviewed By: yfeldblum

Differential Revision: D5418228

fbshipit-source-id: d3a250e1b4fe1f0bc99b44c660df94cf233aebd6

Summary: Add paths of SSLOptions.{cpp, h} to folly/Makefile.am.

Reviewed By: Orvid

Differential Revision: D5453343

fbshipit-source-id: ba0b8b065ed964dfff1757533db17e31aa672e83

Summary: As written, this str() method depends on the current state of the host - if an interface disappears (as is commong with eg. mobile, ipsec, etc.) then attempting to generate a string representation of this v6 address will currently throw an exception. Instead, we're going toignore the lookup failure and append the index i; this form is interchangeable, though slightly less legible.

Reviewed By: yfeldblum

Differential Revision: D5443618

fbshipit-source-id: bbd3b4edaee8098671140af7400377d5e2b1937b

Summary: A folly::atomic_shared_ptr version of CoreCachedSharedPtr.

Reviewed By: yfeldblum

Differential Revision: D5389603

fbshipit-source-id: 942700cd66f5f5219418f4c6112146dc40351aa0

Summary: Windows doesn't have `net/if.h` and instead needs `iphlpapi.h` included, and `ntddndis.h` is ultimately needed to get the definition of `IF_NAMESIZE`.

Reviewed By: yfeldblum

Differential Revision: D5438188

fbshipit-source-id: 48a786f7d10ca4b8479bb20b257ed1e857431654

Summary: This adds a macro `FOLLY_MAYBE_UNUSED` in `folly/CppAttributes.h` that can be used to suppress `-Wunused` warnings.

Reviewed By: yfeldblum

Differential Revision: D5444742

fbshipit-source-id: b16e8efefd76282498ad6114bac9548064cf38d5

Summary:
This diff contains some helper functions that set a `SSLContext` object with recommended
lists of ciphers and signature algorithms for given scenarios. In addition, DES and CHACHA are removed from the cipher list.

Reviewed By: yfeldblum

Differential Revision: D5373599

fbshipit-source-id: 04de11fe90cac734caa12a80e56f70532803f94e

Ensure the allocator types in the string keyed tests have value_types matching the value type of the collection

Summary:
Because MSVC's standard library implementation is now checking that this is actually the case:
```
error C2338: set<T, Compare, Allocator> requires that Allocator's value_type match T (See N4659 26.2.1 [container.requirements.general]/16 allocator_type) Either fix the allocator value_type or define _ENFORCE_MATCHING_ALLOCATORS=0 to suppress this diagnostic.
```

I've gone with the "Fix the `value_type`" approach.

Reviewed By: yfeldblum

Differential Revision: D5441017

fbshipit-source-id: b30403d2e48f815177cac29c4e6eec4e79583660

Summary: 32-bit iOS environments were triggering the previous condition with LifoSem.

Reviewed By: yfeldblum

Differential Revision: D5442057

fbshipit-source-id: 64ee32b4ad35150c7f295a2a30bbede8fa13e79e

Summary: Also use it to disable function_test and indexed_mem_pool_test for now while the source of their breakage is being investigated.

Reviewed By: yfeldblum

Differential Revision: D5440415

fbshipit-source-id: 630c884ccd2db660bfc3e4529a2d35941d3bd0d3

Summary: Lua exception handling test - start with the failing test first - code from D5431445

Reviewed By: yfeldblum

Differential Revision: D5432254

fbshipit-source-id: 87f5934f28ac6ef7b55314acb3c150b9ccf6c799

Summary: `AsyncSignalHandler` is not currently supported on Windows, so we shouldn't be attempting to build it.

Reviewed By: yfeldblum

Differential Revision: D5437276

fbshipit-source-id: b3f281bfc501444bb22056860ee785a2beb9b671

Summary:
- The __GNUC__ macro is used by other compilers like Clang and
  ICC, but ext/stdio_filebuf.h is a libstdc++ only extension.

fixes #636
Closes https://github.com/facebook/folly/pull/637

Reviewed By: yfeldblum

Differential Revision: D5434532

Pulled By: Orvid

fbshipit-source-id: ce4f966a74aa9f82ae907c67807ac87ec1588173

Summary:
There is no longer anything keeping them from working on Windows.
Except for that `signal(SIGPIPE, SIG_IGN)` call; that has to stay disabled.

Reviewed By: simpkins

Differential Revision: D5308007

fbshipit-source-id: 74a392cf484404f41a6c51e50b5a9e6fbd05b4a9

Summary:
[Folly] Let `exception_wrapper::handle`, when empty, show the right error message.

The error message currently says that `throw_exception` cannot be called on an empty `exception_wrapper`, but should say that `handle` cannot be called on an empty `exception_wrapper`.

Reviewed By: Orvid

Differential Revision: D5432380

fbshipit-source-id: ffa69c7675ee332e596e861e59ea273c39fc4717

Summary:
CodeMod: Prefer `ADD_FAILURE()` over `EXPECT_TRUE(false)`, et cetera.

The tautologically-conditioned and tautologically-contradicted boolean expectations/assertions have better alternatives: unconditional passes and failures.

Reviewed By: Orvid

Differential Revision:
D5432398

Tags: codemod, codemod-opensource

fbshipit-source-id: d16b447e8696a6feaa94b41199f5052226ef6914

Summary: Because these are always 64-bit values. This hasn't actually been an issue but is the correct thing to do.

Reviewed By: yfeldblum

Differential Revision: D5425658

fbshipit-source-id: 5bc204b3d1af2c710bd8b1665211d2971ccf7be7

Summary: It is a non-portable include as it is include-order sensitive.

Reviewed By: yfeldblum

Differential Revision: D5427885

fbshipit-source-id: 50850064fc8fa3ed6f8fc235f31edbda4144663c

Summary:
MSVC has issues with the way it was written, so just use the standard version instead.

Upstream bug report: https://developercommunity.visualstudio.com/content/problem/80433/incorrect-error-c2462-cannot-define-a-type-in-a-ne.html

Reviewed By: yfeldblum

Differential Revision: D5427029

fbshipit-source-id: ae3737175d5b8e9738ed6b9573412d1d566b0e1c

Summary: `__gnu_cxx::sfmt19937` is 3.5x faster than `std::mt19937` according to the benchmark.

Reviewed By: yfeldblum

Differential Revision: D5410705

fbshipit-source-id: d503544a0b9b1b0c614a27466a297a4e6902fc15

Summary:
Previously it generated a warning if compiled with -Wover-align because its alignment exceeded alignof(std::max_align_t).

This also meant that heap-allocated LifoSem objects were not guaranteed to be on their own cache-line, potentially degrading performance.

This change adds padding before the important part of the LifoSem (to match the existing after-padding) and reduces its alignment requirement.

Reviewed By: yfeldblum

Differential Revision: D5380700

fbshipit-source-id: 7fdd593a58a2e0c7b03df11152ee4bb66f57e717

Summary: It was shadowing locals.

Reviewed By: yfeldblum

Differential Revision: D5422356

fbshipit-source-id: 91da6fcf0b2ea3821394068e9847976e04f43ca9

Summary: Some implementations of getnameinfo are triggering reverse DNS lookups despite us specifying NI_NUMERICHOST. Avoid all that by instead producing our string representations of v6 addresses manually via inet_ntop and if_indextoname.

Reviewed By: yangchi

Differential Revision: D5415477

fbshipit-source-id: 67853a85db6517d374d94c8261e56400f4c00fc5

Summary:
The C++ standard doesn't guarantee alignment of things bigger than std::max_align_t which is typically 16 bytes. This means that to ensure something is the only thing on a cache-line we need padding on each side of it to exclude anything else.

CachelinePadded<T> will now be larger than it was before, and reinterpret_cast to/from T is no longer valid.

Reviewed By: yfeldblum

Differential Revision: D5380849

fbshipit-source-id: 20f275c875eb4bede4aef19ac7224913ce9b6d51

Summary: Break a few long lines in folly::SSLContext.

Reviewed By: yfeldblum

Differential Revision: D5418517

fbshipit-source-id: fc2ac310d1f931a1f8a4af077aa5cde347b1042d

Summary: There were references to things that don't exist or have an equivalent on Windows.

Reviewed By: yfeldblum

Differential Revision: D5099802

fbshipit-source-id: 9a5a2d0e5cb3a33ecad00bf8a2e1c13315a015cc

Summary:
The file itself will still get removed when `TemporaryFile` is destroyed, but closing it before then allows it to be read when on Windows, because `TemporaryFile` opens the temporary file with `O_EXCL`, so Windows denies read access of the file to everything else.
This is needed to fix one of the AsyncFileWriter tests on Windows.

Reviewed By: simpkins

Differential Revision: D5307719

fbshipit-source-id: bd65962cc3d34f382cc7b0b55dbf2659ed5ebfce

Summary:
There are bugs in MSVC's codegen that causes `StringPiece`'s evaluated in a `constexpr` context to have the start pointer point to one copy of the string and the end pointer point to another. Using the `StringPiece` at compile-time is perfectly fine, it just has the wrong values at runtime.
We can work around this issue by enabling string pooling in all modes.

Original bug report:
https://developercommunity.visualstudio.com/content/problem/3216/c-incorrect-data-duplication-in-constexpr-context.html

Reviewed By: yfeldblum

Differential Revision: D5409753

fbshipit-source-id: 24e2b343209ba7c86d0dd39a1358d0abe9ee6d4d