Summary:
[Folly] Add `FOLLY_HAS_BUILTIN` and use it.

Use it in the definition of `folly::launder`. Of course, since GCC does not have `__has_builtin`, we still have to check its version.

Reviewed By: WillerZ

Differential Revision: D5496748

fbshipit-source-id: 3bd6e89424dfd2c9cb9795ee4d88f66c4294cc4c

Summary:
[Folly] Cut `throwOnFail`.

It is not necessary, and `CHECK_THROW`, its reason for existing, can be implemented without it.

It can also easily be a pessimization because there is no way to delay computation of the arguments to the exception ctor until after the check. So if there is, say, a computation using `sformat` to compute a string argument to the exception ctor, that will always be performed rather than being performed only should the check fail.

Reviewed By: Orvid

Differential Revision: D5478804

fbshipit-source-id: 71a125c126eae76c6e95ef1bd23ee883b1db39a5

Summary:
(1) small_vector.h line 1099: wrap the default return in an else statement to
avoid compiler warning of "unreachable statement".
(2) Constexpr.h: need to treat cudacc similarly to msvc.

(Note: this ignores all push blocking failures!)

Reviewed By: dzhulgakov

Differential Revision: D5387061

fbshipit-source-id: f002ab5ec00d4dcd85d86386f87a0327023afa1b

Summary: [Folly] Move `__CLANG_PREREQ` to `folly/CPortabiilty.h`.

Reviewed By: Orvid

Differential Revision: D5496372

fbshipit-source-id: 710af3d30aa8bd0e5f645beede354e3463f1bb25

Summary:
[Folly] There is no `HAVE_SHADOW_LOCAL_WARNINGS`

It is `FOLLY_HAVE_SHADOW_LOCAL_WARNINGS`.

Reviewed By: Orvid

Differential Revision: D5496247

fbshipit-source-id: 689f40180180465bdc44593059e44fb64cf3e415

Reviewed By: anirudhvr

Differential Revision: D5492790

fbshipit-source-id: 10e868976a7ea42673d5b5c906a53c6c9495a288

Summary: Closes https://github.com/facebook/folly/pull/642

Reviewed By: Orvid

Differential Revision: D5471368

Pulled By: yfeldblum

fbshipit-source-id: 3bbafd04b93828121ba829027959b6b3e0e55888

Summary:
OpenSSL 1.1.0 deprecates the callback based locking setup in favor
for platform native mutexes.

Added `OPENSSL_init_ssl` in the OpenSSL portability module for OpenSSL API < 1.1.0. This implements
the standard OpenSSL library initialization routines (taken from SSLContext::initializeOpenSSL).

Added `OPENSSL_cleanup` in the OpenSSL portability module for OpenSSL API < 1.1.0. This implements
the cleanup routine from SSLContext::cleanupOpenSSL.

Removed `SSLContext::SSLLockType`. Replaced with `folly::ssl::LockType`.

Reviewed By: mzlee, ngoyal

Differential Revision: D5404777

fbshipit-source-id: 7e5d9bf4a6683afb5560ada0a5b73cac3ff2662b

Summary:
If an exception is thrown during the construction of value in a container, then the Transformer iterator will not successfully reconstruct a cache_ object after explicitly calling its destructor (due to the exception being thrown), which results in a double-free when cache_ is destroyed as part of Transformer's destructor.

Conveniently, there exists a piece of code designed to solve just this problem: folly::Optional. Replace cache_ and valid_ with folly::Optional.

This also fixes the unnecessary requirement that container value types have default constructors, since cache_ is no longer default constructed inside of Transformer.

Reviewed By: markisaa

Differential Revision: D5472342

fbshipit-source-id: eade1f7ce260b9b3406d92af8255b5ffa4e4a51c

Summary:
An instance of `Replaceable<T>` wraps an instance of `T`.

You access the inner `T` instance with `operator*` and `operator->` (as if
it were a smart pointer).

`Replaceable<T>` adds no indirection cost and performs no allocations.

`Replaceable<T>` has the same size and alignment as `T`.

You can replace the `T` within a `Replaceable<T>` using the `emplace` method
(presuming that it is constructible and destructible without throwing
exceptions). If the destructor or constructor you're using could throw an
exception you should use `Optional<T>` instead, as it's not a logic error for
that to be empty.

Reviewed By: yfeldblum

Differential Revision: D5346528

fbshipit-source-id: c7d72e73ea04e371325327a7ff0b345315d6e5ac

Summary:
[Folly] Move the SpookyHash libraries into `folly/hash`.

And propagate the changes to `#include` lines, etc.

Reviewed By: Orvid

Differential Revision: D5477735

fbshipit-source-id: 94fe95ece05b52bde1466ab5f9fb8b53a4c59bed

Summary:
[Folly] Outline the `throw` statements in `Try`.

They are by definition cold and so we gain nothing from inlining them.

Reviewed By: Orvid

Differential Revision: D5478237

fbshipit-source-id: f413251a56ca4cbddcf3baea6679a552ae5bb19e

Summary:
Add fnv1-a 64 bit hash to Hash.h.
fnv1-a is supposed to be preferred over
fnv1.

Reviewed By: yfeldblum

Differential Revision: D5453401

fbshipit-source-id: c13f12ef11eb6745c95f3901b14ceafce90ea0ea

Summary:
This reverts commit 616b04579eb6c822023b04840b075f3ac9fbb720

bypass-lint

Differential Revision: D5455584

fbshipit-source-id: afc712fe40121232f52a5bad781350581cec6ce8

Summary:
[Folly] Move the SpookyHash libraries into `folly/hash`.

And propagate the changes to `#include` lines, etc.

Reviewed By: ot, ericniebler, Orvid

Differential Revision: D5455584

fbshipit-source-id: 616b04579eb6c822023b04840b075f3ac9fbb720

Summary: On the non sse42 path, we throw std::runtime_error, but Crc32cDetail.cpp is missing the header for it so it fails to compile on aarch64.

Reviewed By: yfeldblum

Differential Revision: D5468906

fbshipit-source-id: 2d5408621cb2b6758d3501407ed3d2a40d79f1b0

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

Reviewed By: Orvid

Differential Revision: D5468832

fbshipit-source-id: 94a0f82312769be0e8be724c11f97e14425ead10

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

Reviewed By: Orvid

Differential Revision: D5460571

fbshipit-source-id: d19aff829316dd277e65620196e12db8cad46787

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