Summary:
The current implementation of `std::is_nothrow_move_constructible` in libstdc++ implies `std::is_nothrow_destructible`. However, this doesn't seem to be required by the standard, see the notes section of https://en.cppreference.com/w/cpp/types/is_constructible.

Since we know that all Vector and Value sets/maps already satisfy this requirement, let's codify it explicitly.

Reviewed By: nbronson

Differential Revision: D20604544

fbshipit-source-id: bae1e8442585cedb062308b6332bd018cccca2f4

Summary:
F14Node{Map,Set} doesn't require `is_nothrow_destructible<value_type>`.  `clear()` and the destructor are both marked `noexcept`, so they will both terminate if the destructor throws. But `erase()` is not marked `noexcept`, so when the destructor throws during `erase()` the value is left in the map. This could be problematic if the value is half destroyed, or if `eraseInto()` is used.

This diff fixes the problem by marking `destroyItem()` as `noexcept`, so `std::terminate` is called whenever the value destructor throws.

Reviewed By: nbronson

Differential Revision: D20604276

fbshipit-source-id: c52c932d78d6ed61368985a749adf77c27a5a0de

Summary: Add support for non libevent based backends in the AsyncSignalHandler

Reviewed By: kevin-vigor

Differential Revision: D20524116

fbshipit-source-id: fdd49cf75bd51599055239270dd704c496d567e3

Summary:
Compiling with gcc 10.0.1 and -std=gnu++2a, we have the following errors:
```
folly/FBString.h:1013:33: error: no type named 'reference' in 'class std::allocator<char>'
 1013 |   typedef typename A::reference reference;
      |                                 ^~~~~~~~~
folly/FBString.h:1014:39: error: no type named 'const_reference' in 'class std::allocator<char>'
 1014 |   typedef typename A::const_reference const_reference;
```
This is due to the fact many members in `std::allocator` have been remove in C++20: https://en.cppreference.com/w/cpp/memory/allocator

We also have this one due to the new way C++ resolves the comparison operators:
```
folly/dynamic-inl.h:854:20: error: ambiguous overload for 'operator!=' (operand types are 'folly::dynamic::const_item_iterator' and 'folly::dynamic::const_item_iterator')
  854 |   return find(key) != items().end() ? 1u : 0u;
      |          ~~~~~~~~~ ^~ ~~~~~~~~~~~~~
      |              |                   |
      |              |                   folly::dynamic::const_item_iterator
      |              folly::dynamic::const_item_iterator
In file included from folly/dynamic-inl.h:25,
                 from folly/dynamic.h:796,
                 from folly/dynamic.cpp:17:
folly/detail/Iterators.h:80:8: note: candidate: 'bool folly::detail::IteratorFacade<D, V, Tag>::operator==(const D&) const [with D = folly::dynamic::const_item_iterator; V = const std::pair<const folly::dynamic, folly::dynamic>; Tag = std::f
orward_iterator_tag]' (reversed)
   80 |   bool operator==(D const& rhs) const {
      |        ^~~~~~~~
folly/detail/Iterators.h:98:3: note: candidate: 'typename std::enable_if<std::is_convertible<D, D2>::value, bool>::type folly::detail::IteratorFacade<D, V, Tag>::operator==(const D2&) const [with D2 = folly::dynamic::const_item_iterator; D =
 folly::dynamic::const_item_iterator; V = const std::pair<const folly::dynamic, folly::dynamic>; Tag = std::forward_iterator_tag; typename std::enable_if<std::is_convertible<D, D2>::value, bool>::type = bool]' (reversed)
   98 |   operator==(D2 const& rhs) const {
      |   ^~~~~~~~
folly/detail/Iterators.h:84:8: note: candidate: 'bool folly::detail::IteratorFacade<D, V, Tag>::operator!=(const D&) const [with D = folly::dynamic::const_item_iterator; V = const std::pair<const folly::dynamic, folly::dynamic>; Tag = std::f
orward_iterator_tag]'
   84 |   bool operator!=(D const& rhs) const {
      |        ^~~~~~~~
folly/detail/Iterators.h:103:8: note: candidate: 'bool folly::detail::IteratorFacade<D, V, Tag>::operator!=(const D2&) const [with D2 = folly::dynamic::const_item_iterator; D = folly::dynamic::const_item_iterator; V = const std::pair<const f
olly::dynamic, folly::dynamic>; Tag = std::forward_iterator_tag]'
  103 |   bool operator!=(D2 const& rhs) const {
      |        ^~~~~~~~
```
Pull Request resolved: https://github.com/facebook/folly/pull/1329

Reviewed By: markisaa

Differential Revision: D20458078

Pulled By: yfeldblum

fbshipit-source-id: 15a6a4cfa0f71d45046ee2a13914672b3746b9eb

Summary:
LoopController::runLoop is responsible for managing Executor/EventBase keep-alive handle.
This diff introduces a similar level of indirection (LoopController::addTaskEager) to solve the same problem for eager variants of addTask*.

Reviewed By: yfeldblum

Differential Revision: D20613287

fbshipit-source-id: 22388ca3b31664c5fedfd509f2d9bab3d86aab47

Summary:
Modify the TrySemiAwaitable adapter so that it customises the co_withCancellation() customisation-point and passes through the CancellationToken to the underlying awaitable (eg. a Task).

This fixes code that tries to do the following so that the cancellation token propagates to a Task adapted with co_awaitTry().
```
co_await co_withCancellation(cancelToken, co_awaitTry(co_foo()));
```

Reviewed By: andriigrynenko

Differential Revision: D20443798

fbshipit-source-id: 945e0f98abad4cdef0be29365642006c5687ad5f

Summary: Actually use vendored Rust crates when building with CMake. The `--offline` option make sure cargo do not go to the Internet for missing crates.

Reviewed By: simpkins

Differential Revision: D20542672

fbshipit-source-id: ab4af40150c6af8b531a75f503a4fa848b3914da

Summary:
This allows to avoid unnecessary copy of `shared_ptr`.

(Note: this ignores all push blocking failures!)

Reviewed By: andriigrynenko

Differential Revision: D20596972

fbshipit-source-id: 6411ee2f735c1db1984bcd83ceddf80e4ec6f22b

Summary:
Add sampled logging of blocking operations made on folly::Baton from within an executor task.

Relies on thread_local state recording whether we are in a context where blocking is disallowed, which means within a task running on an executor with support for the functionality. Functionality is currently limited to certain executors, and to blocking operations on Baton, but this covers common user-facing APIs like Future.

Reviewed By: andriigrynenko

Differential Revision: D20010963

fbshipit-source-id: c0598e1a3a9c4e3641581e561b678a2b241998ff

Summary:
If you have built the `eden/scm` subdirectory with `make local` in your
repository it will have left a bunch of build output artifacts in the source
tree.  Update the getdeps shipit path map for eden to explicitly exclude many
of these build artifacts.

In particular:
- Exclude `eden/scm/build/` since this directory can contains a lot of files.
- Exclude all `*.pyc` files since there may be a reasonable number of these.
- Exclude several Cargo-related files since these will cause problems when
  trying to build Rust code.

Reviewed By: chadaustin

Differential Revision: D20570720

fbshipit-source-id: a60dec4854ae470fdb58e9651fd8a3b910c76004

Summary:
The default warning settings for the MSVC compiler result in an
extremely noisy build output, to the point where it can take minutes of reading
through pages of output to locate the actual error when debugging a build
problem.  The majority of these warnings are the result of implicit integer
narrowing that is silently permitted in our posix builds.

Rather than blanket suppress these conversion warnings and mask potential bugs,
this commit makes a pass over the code and adds `folly::to_narrow` to a number
of call sites to make it explicit that a narrowing operation is taking place
and that it is (probably!) intentional.   We make a lot of assumptions
throughout our various projects that we won't allow data larger than 2GB
through eg: thrift and as a result, a lot of wire/serialization related code
uses `uint32_t` for sizes instead of `size_t`.

Reviewed By: yfeldblum

Differential Revision: D20562029

fbshipit-source-id: 706ba9cf330d40a2b3f911e5e9a8b9de325ebc80

Summary:
`setCallback()` functions just store the argument as a `Function`, so we don't need to specialize the templates all the way down, we can pass directly a `Function`.

This reduces code size, and should not have runtime impact: either the move is elided in both cases, or if not there's no particular reason why a `Function` move should be more expensive than an arbitrary functor's (could even be faster).

Reviewed By: yfeldblum, luciang

Differential Revision: D20561695

fbshipit-source-id: 1973c47a5410a43eb44beea36cb1105663094eb3

Summary:
OpenNSA has prebuilt SDK but kernel modules have to be built from sources. Add
a utility script to build and extend packaging script.

In future, we can consider folding this build into fbcode_builder itself.

Differential Revision: D20549883

fbshipit-source-id: f9475b7e0223e9f357117d7d7d27df8904fa1d73

Summary: Correct typo

Reviewed By: lewissbaker

Differential Revision: D20544820

fbshipit-source-id: f9edffd0a44448fd558b3e659585044f9be81035

Summary: Updated fmt version to be on par with buck build. It was causing inconsistencies.

Reviewed By: vitaut

Differential Revision: D20528011

fbshipit-source-id: d9e04ed2c28b839eaeff24120162c4db4732fa55

Summary: [Folly] Cut unused `#include`s in `folly/experimental/symbolizer/ElfCache.h`.

Reviewed By: Orvid

Differential Revision: D20482493

fbshipit-source-id: 426ebe0aa55e116e3f3c8095b0c9d0f1babdb354

Summary:
This enables fetching blobs from the LFS server. For now, this is limited to
fetching them, but the protocol specify ways to also upload. That second part
will matter for commit cloud and when pushing code to the server.

One caveat to this code is that the LFS server is not mocked in tests, and thus
requests are done directly to the server. I chose very small blobs to limit the
disruption to the server, by setting a test specific user-agent, we should be
able to monitor traffic due to tests and potentially rate limit it.

Reviewed By: DurhamG

Differential Revision: D20445628

fbshipit-source-id: beb3acb3f69dd27b54f8df7ccb95b04192deca30

Summary: Helper observer which only triggers updates when the value changes.

Reviewed By: bithree

Differential Revision: D20521319

fbshipit-source-id: 77e45d92f710b1701552cf29445f44aa9d9487f4

Summary: Correct use of portability macro.

Reviewed By: yfeldblum, manderyao

Differential Revision: D20520392

fbshipit-source-id: b21fb13aa7a523db21a506b71e65047edbb17684

Summary: Fix two small warnings when building AsyncUDPSocket on macOS.

Reviewed By: fanzeyi

Differential Revision: D20525411

fbshipit-source-id: 39cd84364413d434d261c17c4c8a87e31ac75a42

Summary:
Add support for creating an EventBaseManager with a custom backend factory method

(Note: this ignores all push blocking failures!)

Reviewed By: kevin-vigor

Differential Revision: D20513736

fbshipit-source-id: 62edc876cd1c0667bd7beb85a3d6fbd9a5a03ebf

Return 0(success) in EventBaseEvent::eb_event_base_set if we're trying to use a non libevent backend

Summary: Return 0(success) in EventBaseEvent::eb_event_base_set if we're trying to use a non libevent backend

Reviewed By: kevin-vigor

Differential Revision: D20513609

fbshipit-source-id: 8329c614f728a86d1bd5267652c39c8d4f54f6cd

Summary: Allow the WTCallback to be used with timer managers that have timeoutExpired methods

Reviewed By: kevin-vigor

Differential Revision: D20503031

fbshipit-source-id: df91f1e2531f5c54943d3540bdf7c3d357c9fda1

Summary:
Sometimes it fails to throw exception in [Codel::setOptions](https://github.com/facebook/folly/blob/master/folly/executors/Codel.cpp#L109), since it failed the check `interval <= delay`.

The reason is that both interval and delay are [POD](https://github.com/facebook/folly/blob/master/folly/executors/Codel.h#L80-L81), thus both are not initialized by default.

Using them without initialization is UB. In x86, they will have random value (since x86 doesn't have trap representation), thus sometimes it passes, sometimes it fails.

Based on comment, it looks like the intention is copying the `options` from default initialized `Codel`.

Reviewed By: amlannayak

Differential Revision: D20499449

fbshipit-source-id: e12de0b42c02a8bf6379ba7fd224e0ae173945f0

Summary:
Add eb_signal_set, eb_timer_set methods to be in sync with libevent

(Note: this ignores all push blocking failures!)

Reviewed By: kevin-vigor

Differential Revision: D20513498

fbshipit-source-id: be8d5d0ca362bdaa86cc161f481aea93cc757c75

Summary: A thread-local query for the current executor. Grounding feature for logging operations.

Reviewed By: andriigrynenko

Differential Revision: D20070133

fbshipit-source-id: e320d2a3d97744b91c07a6060708e5cefc517cb7

Summary: Make the hazard pointer-based implementation of request context the default one by setting `folly_reqctx_use_hazptr` to true by default.

Reviewed By: yfeldblum

Differential Revision: D19145252

fbshipit-source-id: 5dd68fb92561685a6ee35d8b3b03a1dcf7e1e356

Summary:
while compiling on windows see duplicated symbols:
```
lld-link: error: duplicate symbol:
public: static char const *const folly::dynamic::TypeInfo<
class std::basic_string<char, struct std::char_traits<char>,
class std::allocator<char>>>::name
in buck-out\dev\gen\crypto\cat\cpp\tests\crypto_auth_token_util_test#compile-CryptoAuthTokenUtilTest.cpp.obj1f5bc0bc,windows-x86_64\out.obj
and in libdynamic.lib(out.obj)
```

Reviewed By: yfeldblum

Differential Revision: D20426321

fbshipit-source-id: 4e0346c624ad12561adb14f3a2e5f6e15bbbba26

Summary:
This workaround is no longer necessary for a Clang that includes
patch https://reviews.llvm.org/D76118.

Reviewed By: ispeters, lewissbaker

Differential Revision: D20486353

fbshipit-source-id: cab137ed557ba8aa6ec86ec7011cc4fc7c46fe82

Summary:
building on windows fails:
```
buck-out/cells/fbsource/gen/xplat/third-party/glog/glogWindows#header-mode-symlink-tree-only,headers\glog/logging.h:698:32:
error: comparison of integers of different signs: 'const unsigned long long' and 'const int' [-Werror,-Wsign-compare]

buck-out/dev/gen/folly/synchronization/hazptr#header-mode-symlink-tree-only,headers\folly/synchronization/HazptrObj.h:397:13:
note: in instantiation of function template specialization 'google::Check_EQImpl<unsigned long long, int>' requested here
            DCHECK_EQ(reinterpret_cast<uintptr_t>(p) & 7, 0) << p << " " << i;
```

Reviewed By: yfeldblum

Differential Revision: D20482798

fbshipit-source-id: 4b661121401890cec113905fc6b53cd9189fcca0

Summary:
e.g. debian doesn't seem to have it
```
$ cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux bullseye/sid"
NAME="Debian GNU/Linux"
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"
```

Reviewed By: mjoras

Differential Revision: D20483097

fbshipit-source-id: 722397ff994336884ed2e5bbf8fe517d4dcf4e6c

Summary:
clang being more strict with obsolete C++14 api, has
completely disabled them in this context.
Pull Request resolved: https://github.com/facebook/folly/pull/1317

Reviewed By: luciang, markisaa

Differential Revision: D20154780

Pulled By: yfeldblum

fbshipit-source-id: 1ff36fecd3406802c3f393dfdd5dbe2f30656567

Summary: Retrying was modified to support SemiFuture returning policy and function, but incorrectly handled the return type propagation. Fix the problem and add a test to verify.

Reviewed By: yfeldblum

Differential Revision: D20462982

fbshipit-source-id: 97b4dad6d83dbbfe7f1846b457bf915c14b9f31a

Summary:
Conv.h's detail::digitsEnough was not decomposing to a constexpr on iOS/Mac toolchains, which resulted in the following call becoming a runtime VLA:

```
char buffer[detail::digitsEnough<unsigned __int128>() + 1];
```

Update to use `numeric_limits<>::digits10`, which allows this function to evaluate at compile-time on iOS/Mac.

Reviewed By: yfeldblum

Differential Revision: D20440659

fbshipit-source-id: d086e367eec0d3b2f35465525cb7406e746e6df7

Summary: Unqualify nearly all uses of `folly::AsyncUDPSocket::ReadCallback::OnDataAvailableParams` since nearly all uses already have `OnDataAvailableParams` in scope.

Differential Revision: D20450063

fbshipit-source-id: c0fd49a7eace44a6edc8086762c44753224788dd

Summary:
This code is new in 9.3.0, introduced upstream with:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ed920373
Unless we qualify folly::reduce() we get the clash
in P127472223 when running the test plan.

Reviewed By: meyering

Differential Revision: D20461173

fbshipit-source-id: 41b21e9215571da2cbd2ef7f817e2d9999083033

Summary: [Folly] `FOLLY_SSSE`, for testing compiler mode support for SSSE3 intrinsics.

Reviewed By: markisaa

Differential Revision: D20414435

fbshipit-source-id: 077a78f880ea8dce44f1aced38a6cca08cdd1f65

Summary: [Folly] Move remove_reference_wrapper to coro traits, since this is not a language-level trait and is there to be used in the coro library.

Reviewed By: iahs

Differential Revision: D20301017

fbshipit-source-id: aa78488cc5138e6ade9dcbc99ec1b75b65c74c78

Differential Revision:
D20443631

Original commit changeset: 03e8210a64a3

fbshipit-source-id: 42621768beab530619aba877015dd48d509bc62b

Summary:
`unsigned int` is a more typical definition of the mode_t type on Linux systems, which is what this is trying to emulate.

Also guard by checking that HAVE_MODE_T isn't already define to allow clients to suppress its definition in cases where other client-used libraries (e.g. wxWindows) have their own definition which may conflict.
Pull Request resolved: https://github.com/facebook/folly/pull/1335

Reviewed By: yfeldblum

Differential Revision: D20408879

Pulled By: scramsby

fbshipit-source-id: 511484f6513501bf595ccb9cdfb893c9d5761320