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

Summary: The style guidelines say control flow should always have curly braces, and we follow that, mostly. This just uses clang-tidy to clean up everywhere that we weren't.

Reviewed By: markisaa, luciang

Differential Revision: D6097377

fbshipit-source-id: bfe6766c37bd863ecf68851ef93265a200d4259d

Summary: as above

Reviewed By: yfeldblum

Differential Revision: D6086563

fbshipit-source-id: ab7f50ba46ebd1dbef6438f956258b2fbb13cb5c

Summary: Simple addition. Easy to track externally, but might as well provide it in the class if it is readily available.

Reviewed By: yfeldblum

Differential Revision: D6093826

fbshipit-source-id: 9d8c02891b2cea9ce0d3f6ea78e1e0055b536eb8

Summary:
This reverts commit 64eb65aac8e3e7cd0126e65ca3998bfe167e2d73

bypass-lint

Differential Revision: D6050464

fbshipit-source-id: 1ed63f30837dc11ae57b316f1f7cb233a210894a

Summary:
AIUI, if there is no executor available, then callbacks are executed inline. `folly::window` uses a recursive helper function (`spawn`) to handle chaining callbacks. So if `window` is used on a large enough collection of `Future`s without executors (e.g., created by `makeFuture`, or have otherwise already completed), you get a stack overflow. A minimal repro looks like:
```

int main(int argc, char** argv) {
  std::vector<int> v(100000);
  for(int i=0; i < v.size(); i++) {
    v[i] = i;
  }

  std::vector<folly::Future<folly::Unit>> f =
      folly::window(
          std::move(v),
          [](int /* unused */) { return folly::makeFuture(); },
          1);
  folly::collectAll(f).get();
}
```

This diff resolves the issue by adding an overload of `folly::window` which takes an executor as its first parameter. The executor-less `window` overload calls through to the new function using an `InlineExecutor` as the default executor.

Reviewed By: yfeldblum

Differential Revision: D6038733

fbshipit-source-id: 5dcab575592650efa2e106f12632ec06817a0009

Summary: [Folly] Move `folly/Hash.h` to `folly/hash/`.

Reviewed By: jsedgwick

Differential Revision: D6050464

fbshipit-source-id: 64eb65aac8e3e7cd0126e65ca3998bfe167e2d73

Summary:
Workaround a bug in template instantiation in MSVC 2017 U3/4 with /permissive-

https://developercommunity.visualstudio.com/content/problem/81223/incorrect-error-c5037-with-permissive.html

/cc Orvid
Closes https://github.com/facebook/folly/pull/691

Reviewed By: yfeldblum

Differential Revision: D6085652

Pulled By: Orvid

fbshipit-source-id: f068dc3f8e474163815fc497b05410fe76834a52

Summary: As titled.

Reviewed By: yfeldblum

Differential Revision: D6087099

fbshipit-source-id: 1c346fa6f65b5ea58e728759905560ae5ad9cc9d

Summary: Compiled mcrouter with the 'Wpadded' flag to try to find any wasted space. Mcrouter itself did not have anything, but there was a lot in AsyncSocket.h and AsyncSSLSocket.h so looked into those and removed a bit of wasted space

Reviewed By: yfeldblum, brianwatling

Differential Revision: D6033977

fbshipit-source-id: 2dc127208e09980be6a5db576b45d30ac6e044ff

Summary: as above

Reviewed By: yfeldblum

Differential Revision: D6076779

fbshipit-source-id: 4c223ab9fce3be8544f6f807781c3d0a99b61dad

Summary:
MSVC has a bug where it is unable to match an out-of-line constructor (and
possibly other kind of member) to the definition if it is implicitly referenced
before the definition is processed. The guilty method is
SemiFuture<Unit> makeSemiFuture(). Moving it after the constructor definitions
resolves the issue.

Reviewed By: yfeldblum

Differential Revision: D6042277

fbshipit-source-id: 97fe97c0edf3df3d9e3b808968b450c73959b600