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

Summary: see title

Reviewed By: yfeldblum

Differential Revision: D6062601

fbshipit-source-id: edd9a5e85f4ebecd1a6f1004a4d3b8b43b935c2b

Summary: [Folly] Move `folly/MallctlHelper.h` to `folly/memory/`.

Reviewed By: aary

Differential Revision: D6087216

fbshipit-source-id: 4e0fa4aea976e2578127d3c340e0e9b559a224ca

Summary: as above

Reviewed By: ngoyal

Differential Revision: D6087941

fbshipit-source-id: 948ff4f2faa87dd34f87d14ea01c83335f850a27

Summary:
Because we do this in a few places, and `nullptr` makes it far clearer what the intention is.
Note that with `-Wzero-as-null-pointer-constant` under GCC, doing `std::function<void()> f = {}` initializes `f` with a `0` rather than `nullptr`, triggering the warning, so I've enabled it there as well.
It is not currently possible to actually enable `-Wzero-as-null-pointer-constant`, because GCC 5 reports conversions resulting from a default value as occuring at the call-site rather than at the location where the parameter is defined, and the default allocator in libstdc++ is not clean for this particular warning -_-...

Reviewed By: yfeldblum

Differential Revision: D6046746

fbshipit-source-id: 6135bb20a503c861838575cf973324d74d75ca69

Summary: as title

Reviewed By: yfeldblum

Differential Revision: D6062437

fbshipit-source-id: 4f99e779e280fdb0b1f035013caff18764e86ab5

Summary: [Folly] Lift the `invoke` helper in `Function.h`.

Reviewed By: aary

Differential Revision: D6050569

fbshipit-source-id: da07901b8d058b0199d23db675c0fb9082fdf67d

Summary: as above

Reviewed By: yfeldblum

Differential Revision: D6076757

fbshipit-source-id: afe144129e8a0242ba6baee96a84a9084e6e2571

Summary: [Folly] Simplify impl of `setThreadName`.

Reviewed By: Orvid, ot

Differential Revision: D6075179

fbshipit-source-id: 720f29cc688f97b936813898238b8eb26b8a6141

Summary: Do not set WriteFlags::WRITE_MSG_ZEROCOPY if the buffer isShared()

Reviewed By: yfeldblum

Differential Revision: D6068711

fbshipit-source-id: fff14dcd4fcb20c9dbb60794420845042518922c

Summary: [Folly] Un-templatize `Range::str`.

Reviewed By: ot

Differential Revision: D6075642

fbshipit-source-id: 08fc399c43750d34463de7634be4fe386b5db97c

Summary:
[Folly] Refactor `ShutdownSocketSet` atomic state machine.

* Format.
* Use `while` over `goto`.
* Avoid `memory_order_acq_rel` as the single-argument memory order; some platforms fail to build that.
* Use `memory_order_relaxed` for all atomic operations because stronger memory orders are not actually required: the atomic state never serves as a barrier for synchronizing loads and stores of associated data because there is no associated data.

Reviewed By: davidtgoldblatt

Differential Revision: D6058292

fbshipit-source-id: d45d7fcfa472e6e393a5f980e75ad9ea3358bab3

Summary:
[Folly] An `InlineExecutor` singleton.

Using the Leaky Meyers Singleton pattern, so that it is always available whenever required.

Differential Revision: D6074534

fbshipit-source-id: bd4c9cd6a1e60c80de5d2eef1cb6a1e7f16b4e50

Summary:
This overload of estimateSpaceNeeded was taking a Src by
value, but Src is constrained by IsSomeString which only returns
true for std::string or fbstring, so this was inducing a copy
in any situation where folly::to<> is used with varargs which
contain fb/string arguments.

Reviewed By: yfeldblum

Differential Revision: D6059517

fbshipit-source-id: adc239f9049e161fc4b750bae0e3de5dbdcd1bfc

Summary:
[Folly] Make `Range.h` and `FBString.h` mutually independent.

This means that `Range` cannot directly know about `fbstring`, so any interactions between the two types must be indirected through templates.

Motivation: `FBString.h` is a relatively heaviweight `#include` for things that need `Range.h` but which do not use `fbstring`.

Reviewed By: ericniebler

Differential Revision: D6062434

fbshipit-source-id: e2f21c33f482eadffd0a8679eff4ece59bab53e9

Summary:
[Folly] Shrink integral `hasher` specialization implementations.

Instead of giving them bodies, just use inheritance.

Reviewed By: luciang

Differential Revision: D6067757

fbshipit-source-id: f71bd36132e1b66002493474825894b03754b34f

Reviewed By: simpkins

Differential Revision: D6068742

fbshipit-source-id: a3b3b7fe4a6da8f250e5b9593f66b9f8a9345136

Summary: Closes https://github.com/facebook/folly/pull/692

Differential Revision: D6066294

Pulled By: yfeldblum

fbshipit-source-id: a533527058b8b5bc71fb6f40bad31a50e8c3f585

Summary:
[Folly] 4-way overloads for `SemiFuture::value`.

Overload on the receiver reference category and `const`-qualification, deriving the return type reference category and `const`-qualification. Like `Optional`, `Try`, etc.

Differential Revision: D6062006

fbshipit-source-id: d7396cd4d4bb62e99445d5f61cb360898fa1c3f3

Summary:
`folly/Hash.h:379:12: error: implicit instantiation of undefined template 'folly::hasher<unsigned long, void>'`
So, folly is unable to hash the very type it returns: `size_t`. Namely, folly has overloads for `uint32_t` and `uint64_t` which on my Mac map to `int` and `long long` respectively. `size_t` on the other hand maps to `long` which is neither.
Rather than overloading library types (which are just typedefs), we should overload all the built-in types: `char`, `short`, `int`, `long`, `long long`, `signed` and `unsigned` variants (with special treatment of `char`).

Reviewed By: yfeldblum, luciang

Differential Revision: D6051600

fbshipit-source-id: d59569dab963cbe0329aa589ff321cfb22308193

Summary:
Partially inspired by WillerZ's investigation into faster compiling
StringPiece work, I thought this would be an easy drop in that short
circuits some compilation logic (or possibly is strictly better, since the
StringPiece conversion method isn't constexpr).

Reviewed By: yfeldblum

Differential Revision: D6059537

fbshipit-source-id: 072f56e58aa47db10b54825cac8a05dc035b295c

Summary: folly/futures depends on folly/Random.h, which in turn depends on <random>, which is a fairly large header. Most users of folly::futures do not use retrying, so separate it into a separate header.

Reviewed By: yfeldblum

Differential Revision: D6028468

fbshipit-source-id: d8155fe2ddff1a65c265a18f040ee6f1be3f3f0a

Summary:
[Folly] Style fixes for `folly/experimental/gdb/README.md`.

Should have no effect on Github rendering, but should affect PHabricator rendering.

Reviewed By: Orvid, kennyyu

Differential Revision: D6055017

fbshipit-source-id: 54204a2b77beeb884cdc486207809f78ac80afe2

Summary: Add AsyncSocketException.cpp to the list of files to build in Makefile.am

Reviewed By: knekritz

Differential Revision: D6051989

fbshipit-source-id: 72083a609fc994770eca078bfef5a0ed04322bfc

Summary:
We recently found out that ShutdownSocketSet consumes 150+MB for our service, which uses duplex channels. The problem is that we create ~1000 of ThriftServers, and each of the creates its own ShutdownSocketSet.
In reality, ShutdownSocketSet is only needed to kill all socket's FD in emergency before crash dump is taken, so they don't hand around waiting for crash dump to complete. There is no need to keep a SSS per ThriftServer, singleton should work just fine.
There is a problem here, though. Currently a ThriftServer has 'immediateShutdown' method, which kills all sockets from SSS. So, if SSS becomes a singleton, and we have more than one ThriftServer, calling 'immediateShutdown' on one will kill sockets from the other one. First, it's a quite surprising behavior, and second, it complicates unit tests, which emulate thrift servers running in different processes.

As a result,
1. ShutdownSocketSet is created as a singleton, but each ThriftServer still keeps weak ptr to it (mostly for unit tests support).
2. replaceShutdownSocketSet method is added to ThriftServer.h, so unit tests could set different SSS for different ThriftServers.
3. method immediateShutdown is removed from ThriftServer, because its behavior would be 'surprising'.

There still may be unexpected consequences of this change for the tests because of Singleton, but let's see.

Reviewed By: yfeldblum

Differential Revision: D6015576

fbshipit-source-id: dab70dbf82d01bcc71bbe063f983e862911ceb24

Reviewed By: yfeldblum

Differential Revision: D6042832

fbshipit-source-id: c716ee672c4acfa39cab9f10f3b3f88ca770cd20

Summary: [Folly] Move `folly/Checksum.h` into `folly/hash/`.

Reviewed By: Orvid

Differential Revision: D6045825

fbshipit-source-id: 02d3e6a49e2c0fc115cfee09e1186be7a13525ba

Summary: Newer versions of clang >=3.4 support intrinsic constexpr

Reviewed By: Orvid

Differential Revision: D6008856

fbshipit-source-id: 4e40a7032464216d181d76a854cafb2ab4be1be0

Summary:
According to folly::Singleton::try_get(), https://fburl.com/23wqby9i, the caller is responsible for handling a nullptr return. In this case, we handle it poorly, via a crash both in production and debug code.

This diff opts for handling the nullptr more gracefully, via a future loaded with an exception.

Reviewed By: yfeldblum

Differential Revision: D6006864

fbshipit-source-id: e8fde57ed161b33fa1f157ce663ed85e69640c25

Summary: Add SO_ZEROCOPY support

Reviewed By: djwatson

Differential Revision: D5851637

fbshipit-source-id: 5378b7e44ce9d888ae08527506218998974d4309

Summary:
[Folly] Let `EventBase::runInEventBaseThreadAndWait` consume its argument.

Likewise `EventBase::runImmediatelyOrRunInEventBaseThreadAndWait`.

And enforce that the function is destructed before returning, so that, in the case of a wrapped lambda, all captured objects' destructors run before returning from the function.

Reviewed By: elsteveogrande

Differential Revision: D5994106

fbshipit-source-id: 816c9431a85a3d41e4fda321065614f4c18f0697