Summary: [Folly] Move `folly/Assume.h` to `folly/lang/`.

Reviewed By: luciang, ot

Differential Revision: D6181983

fbshipit-source-id: 25564bb07daa1a6765651cd919b4778efb931446

Summary:
BitIterator is a standalone construct that has a heavy boost
dependency, but not common usage. Breaking it out into its own header
will help a lot of transitive dependendencies, because it is included
in Hash.h which is included in a variety of other common headers.

This reduces the number of transitively included headers by 248 (!)

Reviewed By: yfeldblum, ot, luciang

Differential Revision: D6178564

fbshipit-source-id: 1380154b012615b7b8c73bc15ab0ac62f6b990d3

Summary: [Folly] Move `folly/detail/AtomicUtils.h` to `folly/synchronization/detail/`.

Reviewed By: Orvid

Differential Revision: D6180482

fbshipit-source-id: 5671c149a59eea824db2935ffabcf85a2f78b690

Summary: when queues fill, this starts blowing up, affecting server performance and making logs useless. It's useful to know queues are full, but we don't need the log every time we try to append

Reviewed By: yfeldblum

Differential Revision: D6175784

fbshipit-source-id: b4e6966087c4a6f9fba51d7f9193b9f41e13b899

Summary:
[Folly] Fix `FunctionScheduler::resetFunctionTimer` concurrency bug.

The original code from the blamed diff code has a comment with this correct assessment of the bug:
> TODO: This moves out of RepeatFunc object while folly:Function can potentially be executed. This might be unsafe.

Namely, when the method is invoked with the id of a scheduled function which is concurrently being executed, the function object (including, say, lambda captures) will be moved while possibly being accessed. If the function object is small enough to be placed in-situ within `folly::Function` (48 bytes on x64), then that access to a moved-from object can happen. It might or might not, depending on the particular instance of the race in question. Or, worse, the access might be to a half-moved-from object!

The new test case for `resetFunctionTimer` passes after the fix, but is guaranteed to fail before the fix because we manage to control the concurrency enough to force the bad version of the race to happen. In the test, we just capture a `std::shared_ptr` (we could have capatured, e.g., a `std::unique_ptr` or a long-enough `std::string`) and check that it is not empty - if it is moved from, it will be empty, and the test expectation will fail.

Reviewed By: simpkins

Differential Revision: D6158722

fbshipit-source-id: 33a7ae699bb3b22089fddbebb6d922737668309d

Summary: [Folly] `type_t`, a generalization of `void_t`.

Reviewed By: ericniebler

Differential Revision: D6082913

fbshipit-source-id: f9557b5da1f6684b12d570b6c1bd52c102cb0703

Summary: As suggested late in the initial diff (D5840883), just mark it volatile, as it works under all supported platforms.

Reviewed By: davidtgoldblatt, yfeldblum

Differential Revision: D6155241

fbshipit-source-id: 00c07a11dc7fc2e33c2d1f9a45fd28006eeff6f9

Summary:
It defines `MSG_ERRQUEUE` which breaks things.

There's a github PR to do this in a different way, but it's faster to just do it myself.

Closes https://github.com/facebook/folly/pull/689

Reviewed By: yfeldblum

Differential Revision: D6155606

fbshipit-source-id: f1c6b247efc452b4005ad3b6d82fabfd5a92f49f

Disable zerocopy if we're notified about deferred copies, add a isZeroCopyWriteInProgress method, replace pair with a proper struct

Summary: Add zeroWriteDone callback

Reviewed By: djwatson

Differential Revision: D6097129

fbshipit-source-id: b82a942557680c3a7a3be8f81ee6f2886e99e165

Summary:
[Folly] `Expected` coroutines support.

Copied from `Optional` coroutines support.

Reviewed By: ericniebler, Orvid

Differential Revision: D5923792

fbshipit-source-id: 8661012c65762a0e540a4af2fd2fc237a8cb87a1

Summary:
Data race reported by TSAN:

```
WARNING: ThreadSanitizer: data race (pid=608219)
  Read of size 1 at 0x7b5800000c29 by thread T314:
    #0 0x60b3441 in folly::Codel::overloaded(std::chrono::duration<long, std::ratio<1l, 1000000000l> >) ./folly/executors/Codel.cpp:76
    #1 0x5c1222 in apache::thrift::concurrency::ThreadManager::ImplT<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > >::Worker<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > >::run() ./thrift/lib/cpp/concurrency/ThreadManager.tcc:119
    #2 0x5d803e7 in apache::thrift::concurrency::PthreadThread::threadMain(void*) ./thrift/lib/cpp/concurrency/PosixThreadFactory.cpp:200
    #3 0x619739d in __tsan_thread_start_func crtstuff.c:?

  Previous write of size 1 at 0x7b5800000c29 by thread T315:
    #0 0x60b33e4 in folly::Codel::overloaded(std::chrono::duration<long, std::ratio<1l, 1000000000l> >) ??:?
    #1 0x5c1222 in apache::thrift::concurrency::ThreadManager::ImplT<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > >::Worker<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > >::run() ./thrift/lib/cpp/concurrency/ThreadManager.tcc:119
    #2 0x5d803e7 in apache::thrift::concurrency::PthreadThread::threadMain(void*) ./thrift/lib/cpp/concurrency/PosixThreadFactory.cpp:200
    #3 0x619739d in __tsan_thread_start_func crtstuff.c:?

  Location is heap block of size 768 at 0x7b5800000c00 allocated by main thread:
    #0 0x616ab83 in operator new(unsigned long) ??:?
    #1 0x53cb92 in __gnu_cxx::new_allocator<std::_Sp_counted_ptr_inplace<apache::thrift::concurrency::SimpleThreadManager<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > >, std::allocator<apache::thrift::concurrency::SimpleThreadManager<folly::LifoSemImpl<std::atomic, folly::Baton<std::atomic, true, true> > > >, (__gnu_cxx::_Lock_policy)2> >::allocate(unsigned long, void const*)
    ...
```

It looks like there are multiple threads reading and writing the `overloaded_` bool. To fix it, wrap it in a `std::atomic`.

Reviewed By: yfeldblum, meyering

Differential Revision: D6149766

fbshipit-source-id: 605b29fa2f602d2ed2dfc22e46b739ef169f914e

Summary:
the current implementation had problems with scheduling reads and writes and
it would sometimes get stuck when transfering large chunks of data

here I am restructuring the code to look more like the one in HTTPSession

session flow control is not implemented yet really, it's coming next

Depends on: D6048238

Reviewed By: afrind

Differential Revision: D6048238

fbshipit-source-id: ae601e771154a7f1a669a58a6e05c9e3720e7017

Reviewed By: yfeldblum

Differential Revision: D6142252

fbshipit-source-id: 9ac98585a92299ca5915982c65c7d2cfa68bf60f

Summary:
[Folly] Flesh out `Optional` members `swap`, `reset`, `emplace`, `has_value`.

* `swap` as a member and deriving `noexcept`-ness to mimic `std::optional::swap`.
* `reset` v.s. `clear` to mimic `std::optional::reset`.
* `emplace` returning ref and overload taking initializer list to mimic `std::optional::emplace`.
* `has_value` v.s. `hasValue` to mimic `std::optional::has_value`.

Reviewed By: WillerZ

Differential Revision: D6132775

fbshipit-source-id: 34c58367b9dc63289e4b9721c5e79b1c41ba31e4

Summary: [Folly] Simplify `IsUniquePtrToSL` in `IOBuf.h`.

Reviewed By: Orvid

Differential Revision: D6131231

fbshipit-source-id: b054ef7ef9f313943a3ac1022ca6a23874a464df

Summary: [Folly] Move `folly/Hash.h` to `folly/hash/`, leaving a shim.

Reviewed By: Orvid

Differential Revision: D6132955

fbshipit-source-id: dc789e9c6daa28116be6a5d83c3cfbb40e247114

Reviewed By: meyering

Differential Revision: D6117783

fbshipit-source-id: 048b056e119bf89ab88c33b1233297d197e8acb9

Summary: Via clang-tidy's modernize-use-bool-literals

Reviewed By: yfeldblum

Differential Revision: D6130384

fbshipit-source-id: 359d5195897f04612c9b9042cf69383050a2ec7a

Summary: It's done in a lot of places, but not all. clang-tidy gives us llvm-namespace-comment, which can force this consistently.

Reviewed By: yfeldblum

Differential Revision: D6108129

fbshipit-source-id: 1b44c5a26250364f9edf70f84173e9ba6389f06c

Summary: Via the modernize-make-shared from clang-tidy

Reviewed By: yfeldblum

Differential Revision: D6129464

fbshipit-source-id: 04f560c6beeb2b8631b819fd4e6a2d51b37eeb4b

Summary: ManualExecutor::run() is stable, which means that in cases where we want to fully drain the executor we have to loop over it. This adds ManualExecutor::drain() which does that internally.

Reviewed By: yfeldblum

Differential Revision: D6126840

fbshipit-source-id: e36cba5c373a57fe01de244977ec852636b58dbd

Summary: this is all non-hphp includes that are going in container/

Reviewed By: mzlee, yfeldblum

Differential Revision: D6121745

fbshipit-source-id: b024bde8835fc7f332686793d75eb8e71591c912

Summary:
tcache.flush may fail if tcache is disabled.  Avoid using mallctlCall
which throws on error.

Reviewed By: davidtgoldblatt

Differential Revision: D6115419

fbshipit-source-id: 39411c80af08dc7c855efd43297809b749f935bf

Summary: Via the clang-tidy check modernize-make-unique.

Reviewed By: yfeldblum

Differential Revision: D6107790

fbshipit-source-id: 1cf186feae511cbd91f44893059737a85778b6cf

Summary: Rename `std::unique_lock` variables named `lock` to `ulock` in `folly::fibers::TimedMutex` member functions in order to avoid shadowing.

Reviewed By: andreazevedo

Differential Revision: D6123449

fbshipit-source-id: 5fa331bb1541ac995d9b69360ee09923c14f6698

Summary: Only available in >= 2017 15.3, which is 1911+.

Reviewed By: aary, Orvid

Differential Revision: D6117237

fbshipit-source-id: 255804af5bfd0c743fd225b8a4fddf3cfc9cfeaf

Summary: all memory/-destined components besides hphp includes

Reviewed By: yfeldblum, mzlee

Differential Revision: D6121822

fbshipit-source-id: 6c6214d84dcdefe4789ed5200399ae27203d6340

Summary: also gotta split it up/rename it, that's coming later

Reviewed By: yfeldblum

Differential Revision: D6121525

fbshipit-source-id: 9c6dbabd47323d94657508a0f75a0c6e7f988ace

Summary:
That's everything that's going in executors/ except for Executor.h
itself, which is included in hphp so will have to wait

Reviewed By: mzlee

Differential Revision: D6100274

fbshipit-source-id: 6be37892b1ad7f46828acfa6b2951e51b157a86a

Summary:
Everything that's going in system/ besides CpuId and Subprocess,
which are included in hphp

Reviewed By: mzlee

Differential Revision: D6102263

fbshipit-source-id: 564ef584c341a4ac79db14a9d58fe23ce51e78b3

Summary:
as above

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D6099826

fbshipit-source-id: 20152487135aa8eaf6d2e99369801b6dde4992aa

Summary:
[Folly] Use `folly/portability/GTest.h` in `folly/executurs/test/`.

Applying the general rule for folly tests to some recently-introduced violations.

Reviewed By: Orvid

Differential Revision: D6113707

fbshipit-source-id: f9a2961ac845489b85b5a539595e4c82df03d922

Summary:
as title, see moves

(Note: this ignores all push blocking failures!)

Reviewed By: mzlee

Differential Revision: D6112001

fbshipit-source-id: 1eb10b44ae8ee1f90a10e05c29e48c99d824afa5

Summary:
This is C++, not C, so let's keep things modern.
This is applying the modernize-redundant-void-arg clang-tidy check to Folly.

Reviewed By: yfeldblum

Differential Revision: D6106921

fbshipit-source-id: 06a56f036f59426df5dd475bf91a3f4a335266f5

Summary: Via the clang-tidy check misc-argument-comment.

Reviewed By: yfeldblum

Differential Revision: D6107482

fbshipit-source-id: a1fe6215c31fae472ad3b6e05abea974d706794e

Summary: This time aided by clang-tidy's modernize-use-nullptr check.

Reviewed By: yfeldblum

Differential Revision: D6102739

fbshipit-source-id: aeb4bd0a8078d81cc88b766e0a034a37dd25fd1f

Summary: as above

Reviewed By: knekritz

Differential Revision: D6088687

fbshipit-source-id: 0efbb7f5fa33b5f553c0c2019658370fc6e8613f

Summary: When timekeeper singleton no longer exists during shutdown and folly::Singleton::try_get() can return nullptr, make sure nullptr is handled gracefully.

Reviewed By: yfeldblum

Differential Revision: D6101311

fbshipit-source-id: fefeddfbd048d1a7632688bb3526db15b685dd72

Summary: [Folly] Add `InlineExecutor.cpp` to `Makefile.am`.

Reviewed By: Orvid

Differential Revision: D6101859

fbshipit-source-id: 4cd0f875dedb548189722fd719f4424d485e1b02

Summary:
[Folly] Fix `folly/fibers/` build on older boost.

Where `jump_fcontext` takes `intptr_t` rather than an actual pointer, and we warn about implicit conversions from pointers to integral types.

Reviewed By: Orvid

Differential Revision: D6098230

fbshipit-source-id: 61bd7bdff5de728d3febe8b35c97d024ab6f236a