Summary: So that the fd overload can be removed.

Reviewed By: yfeldblum

Differential Revision: D13628683

fbshipit-source-id: 5201d3ef351042ebaf2d30c3987b931f8d13d336

Summary: [Folly] `folly::chrono::abs`, backporting `std::chrono::abs`.

Reviewed By: nbronson

Differential Revision: D13584287

fbshipit-source-id: 92adbfcdac34d89674e6494af4ff3329d2f6974a

Summary:
There is a need for KeepAlive copy constructor from various users. Adding them after chatting with Andrii.
Background: move is preferred to copy as the latter does an atomic counter increment. `copy()` was introduced but there is a need for more user-friendly way of copying.
TODO: maybe get rid of `copy()` and its usages?

Reviewed By: andriigrynenko

Differential Revision: D13864057

fbshipit-source-id: 38b2e45285566a3c2dba01706e82f421285b6bae

Summary: Pull Request resolved: https://github.com/facebook/folly/pull/1006

Reviewed By: Orvid

Differential Revision: D13782299

Pulled By: calebmarchent

fbshipit-source-id: 7662c67a18c10a04d8d68e3f729da81c6df38336

Summary:
Even though this is a test, we are still reallocating a vector (resizing until re-sized/reallocated to 32), which in theory calls for allocation 5 times. But we can save this by just reserving the vector pre-hand (we know the size).
Pull Request resolved: https://github.com/facebook/folly/pull/998

Reviewed By: magedm

Differential Revision: D13834292

Pulled By: yfeldblum

fbshipit-source-id: 6b0d16ef0200184d10ba292a0b1d8d3afdadf56d

Summary: Adds functions for DH length to the compat library.

Reviewed By: yfeldblum

Differential Revision: D13584117

fbshipit-source-id: ef753d58ee400fbaf8d47f59b7d39e17380ed417

Summary:
[Folly] Apply `clang-format` to non-compliant locations (partial).

(Note: this ignores all push blocking failures!)

Reviewed By: igorsugak

Differential Revision: D13858983

fbshipit-source-id: 668c3ee209456befd3c03d85945321143da2b00a

Summary: They aren't needed

Reviewed By: yfeldblum

Differential Revision: D13855963

fbshipit-source-id: c822a4b806350ef178906401b2239a865fd77119

Summary: It was broken due to oddities with how MSVC handles expanding `##__VA_ARGS__` within the parameters to macros. Rather than deal with the pre-processor, just return the check to how it was and use `EXPECT_TRUE(false)` to achieve the same effect.

Reviewed By: yfeldblum

Differential Revision: D13850142

fbshipit-source-id: 887b39fb3c6072219c3f4748599bc7b707efbf25

Summary: [Folly] SemiFuture::deferError and Future::thenError overloads taking exception-type-carrying tag to distinguish the exception type. Solves the case where `.deferError` or `.thenError` is called on an object with a dependent type, where passing the exception type otherwise requires the `template` keyword.

Reviewed By: LeeHowes

Differential Revision: D13855497

fbshipit-source-id: 74200853043e3fdbc08419b33b959f3519d704ef

Summary: [Folly] A generic tag type for all your generic tag-related needs. With naming following the pattern of `std::in_place_t` and `std::in_place`.

Reviewed By: kirkshoop

Differential Revision: D13855499

fbshipit-source-id: 50b7e41fbbb843c6c9b766f8b66484d6aa23c167

Summary:
`value_before` looks like a pre-C++11 artifact, replace with `std::prev`.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D13852269

fbshipit-source-id: c2e4e8178754a694650f53633f099d05da4127d7

Summary:
Upgrade locks allow access concurrently with readers, so mutating the state under an upgrade lock can potentially introduce a race unless proven otherwise.
The main goal of this diff is to make the accessors to `Synchronized` state `const` under upgrade lock, as it happens under a shared lock. To achieve so, the diff changes the mechanism by which `const` is added: instead of unconditionally closing a `const Synchronized` in the `LockedPtr`, it captures the same constness as the `Synchronized`, and then the `const` decision is done at access time.

This enables having an extra method `asNonConstUnsafe()` that gives non-const access when needed without requiring a `const_cast`. This is now provided for shared locks as well.

Reviewed By: yfeldblum, aary, davidtgoldblatt

Differential Revision: D13817413

fbshipit-source-id: 8c315a925db9b1da8821984c59e55e90571b194e

Summary: [Folly] Apply `clang-format` to `folly/FBString.h`. A previous change was not properly formatted.

Reviewed By: ot

Differential Revision: D13831558

fbshipit-source-id: 318404a3a14d6969cc2aa9601e72fae6ad6cfac2

Summary: Remove duplicate code from Future::onError and have it call Future::thenError.

Reviewed By: yfeldblum

Differential Revision: D13823960

fbshipit-source-id: d2e48e4e65e30c80adbbd70ff314e1a418b7c1e2

Summary: As per Yedidya Feldblum comment on my previous diff, we need a duration cast in here.

Reviewed By: yfeldblum

Differential Revision: D13833032

fbshipit-source-id: 8819694875bd3a7e4f54102d8ac77490f8287fbb

Summary:
* Split thenError into future-returning and not-future-returning forms as we cannot rely on onError for this.
 * Move core functionality from onError into thenError to avoid thenError depending on onError.
 * Makes thenError's continuation consistent with other forms such that the parameter is passed by r-value, hence an l-value reference is no longer valid.

Reviewed By: yfeldblum

Differential Revision: D13820171

fbshipit-source-id: cf42a7d1c0759c5cfbb03f8e66a6d6988f7e10c7

Summary: This makes it easier to debug and diagnose build problems

Reviewed By: simpkins

Differential Revision: D13831342

fbshipit-source-id: 3921a05715fb00264b2e1a6e134686d68aea804d

Summary: [Folly] Cut various sites supporting MSVC <= 2015, which is insufficiently compatible.

Reviewed By: Orvid

Differential Revision: D13747631

fbshipit-source-id: 3d63d3a57258b5695b1236a81f3ddfe2f4af9cb4

Summary:
Title. This gets rid of benign TSAN lock order inversion detections.

(Note: this ignores all push blocking failures!)

Reviewed By: spalamarchuk

Differential Revision: D13820662

fbshipit-source-id: f092a988faa2cc897a1d046385e4bc4fd0422c7c

Summary: Add an HHWheelTimer-fwd.h header

Reviewed By: djwatson

Differential Revision: D13780411

fbshipit-source-id: 795352c3eeed38cd52a270ebdf5dd734604415fa

Summary:
This should allow more direct testing of changes without waiting for things to land on github first.

As part of this, to avoid a conflict between the deps that bistro downloads and those used by
the rest of the fbcode builder CI, I've updated the version of gtest used by bistro.

Reviewed By: zertosh

Differential Revision: D13802637

fbshipit-source-id: fd71bfabd2a85f4f63c21b44a1e868f2d293180a

Summary: This is useful to avoid extra allocations when integrating with code that doesn't use folly::futures.

Reviewed By: yfeldblum

Differential Revision: D13812866

fbshipit-source-id: aa76b8cda43d1a781e058f6edbe2ecb8100268de

Summary: The headers are installed, but we weren't compiling the implementation.

Reviewed By: simpkins

Differential Revision: D13778568

fbshipit-source-id: 4d297b732d1e70bbd69100f13eb68f9477d7f014

Summary: This helps avoid executor re-schedule when Future is ready.

Reviewed By: yfeldblum

Differential Revision: D13805939

fbshipit-source-id: f553c7a581882a7b53b004fd6bbb5087ea5787f8

Summary: Currently, `runOnDestruction` aims to be thread-safe; new callbacks are added to the `onDestructionCallbacks_` list while the associated mutex is held. However, the caller may own the `LoopCallback` and wish to destroy/cancel it before the `EventBase` destructor runs, and this callback cancellation is not thread-safe, since unlinking does not happen under the lock protecting `onDestructionCallbacks_`. The primary motivation of this diff is to make on-destruction callback cancellation thread-safe; in particular, it is safe to cancel an on-destruction callback concurrently with `~EventBase()`.

Reviewed By: spalamarchuk

Differential Revision: D13440552

fbshipit-source-id: 65cee1e361d37647920baaad4490dd26b791315d

Summary: Apply timed reclamation to tagged and untagged lists to avoid accumulating a large amount of unreclaimed memory in use cases with large protectable structures.

Reviewed By: davidtgoldblatt

Differential Revision: D13779937

fbshipit-source-id: e2e14ac5f18c1ee30808116cbc29d21895d9fb1c

Reviewed By: yfeldblum

Differential Revision: D13800383

fbshipit-source-id: 61b988182cb8da6f084b62a0879f0ca917f8ad34

Summary:
Current implementation will loop over bitmap to figure out next tick to schedule. This consumes visible amount of CPU (10% in fibers benchmark, ~4% of Thrift noop load test).

However, this looping is unnecessary, because we already have all information available - what is the earliest pre-existing timeout (expireTick_) and the new one. So we can decide what tick to schedule for by just simple conditional statement.

Reviewed By: vitaut

Differential Revision: D13709523

fbshipit-source-id: b0e3e6301cc2e759b4e8901ba5ff009587516cf5

Summary: Got outdated in D3143931.

Reviewed By: yfeldblum

Differential Revision: D13494612

fbshipit-source-id: e24bfea36896ec04b15fa443348e00f50f75940d

Summary: setCallback_ is an internal API that doesn't provide a guarantee that when the callback is run the Try will be stored inside of the original future. Thus the Try should be moved by the callback instead.

Reviewed By: LeeHowes

Differential Revision: D13793991

fbshipit-source-id: 1e8c4e423b8e1786099cae84bd99ac350c32d937

Summary: make an adapter executor that forwards add to addWithPriority of the underlying executor

Reviewed By: andriigrynenko

Differential Revision: D13788642

fbshipit-source-id: 5b4af43f4a3a3931817a2425890558f811152225

Summary: [Folly] Cut `pushmi` example which uses non-yet-`std` names.

Reviewed By: kirkshoop

Differential Revision: D13777367

fbshipit-source-id: 7ae846e74b622fb0f434220961d35bb243be6868

Summary:
Most of the tests that use this macro, use it to ensure proper behavior of time-related logic (i.e. timeout didn't fire too early/late). Skipping them, simply masks a failure. The underlying utility already takes care of lags due to scheduling, so whenever this check fails - means we have a bug.

In particular, we have 3 tests for HHWheelTimer that are always skipped, because their tolerance is below the expected lag of HHWheelTimer (it always rounds up, so we should expect +1ms always).

Reviewed By: vitaut

Differential Revision: D13746558

fbshipit-source-id: 78f954f52414e640af92e5bb50790135cdd89a92

Summary: was reading coro example and i think a line is missing

Reviewed By: andriigrynenko

Differential Revision: D13788989

fbshipit-source-id: ceb024a36ddd89369ee25f6632fce8d339c489cb

Summary: [Folly] Tweak deletion of `fbstring::operator=` taking convertible-to `char`.

Reviewed By: Orvid

Differential Revision: D13747744

fbshipit-source-id: f254f13a15cb0e72120d1d02f4c8893a788e429a

Summary:
Make sure SCOPE_FAIL works with std::rethrow_exception().

When compiled with older versions of gcc this code would fail due to a gcc
bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62258
The gcc bug was fixed in 4.9.4, 5.3, and the 6.0 branch.

Reviewed By: meyering

Differential Revision: D3280778

fbshipit-source-id: 8fe1a9c1dc3ada61c8ebd7318538ae959b29a6b1

Summary:
The other tests are either simple API tests for single-threaded cases, or a
benchmark.

Reviewed By: djwatson

Differential Revision: D13678336

fbshipit-source-id: 5aba91879d756097f42d245b5d318ad7c945dfeb

Summary:
Until C++17 constructor type deduction becomes a thing, we can use this
instead to mimic unique_lock construction without having to specify the type
of the mutex explicitly.

```
auto lck = folly::make_unique_lock(mutex);

// as opposed to

auto lck = std::unique_lock<MutexType>{mutex};
```

Reviewed By: davidtgoldblatt

Differential Revision: D10386999

fbshipit-source-id: 0780a6d1769597a3888305248bcdf93a84c9f9ee

Summary: See F14.md changes.

Reviewed By: nbronson

Differential Revision: D13722323

fbshipit-source-id: 70c68442cad56efc84bb29f0b694a7b71f837cbd