Reviewed By: yfeldblum

Differential Revision: D7765404

fbshipit-source-id: 3f09d6806d0fb98cb59529adc6ea2d51fa7ccbbb

Summary:
BufferedStat hooks up the DigestBuilder and a Digest or a SlidingWindow

Every windowDuration time, the DigestBuilder builds a new digest that will be merged into the central data structure (either a digest or a sliding window of digests).

This diff removes the shared buffer from DigestBuilder, as the concurrency model was getting overly complex with it.

Reviewed By: simpkins

Differential Revision: D7629082

fbshipit-source-id: 54027363d37c0fdced287550eea5b12caf6b8138

Summary: [Folly] Use `is_invocable_r` in `MapUtil` v.s. reimplementing it.

Reviewed By: aary

Differential Revision: D7771481

fbshipit-source-id: 41565a06198ed2289206f01a088c3c1b3a01bc8e

Summary: [Folly] Use `is_invocable_r` in `FunctionRef` v.s. reimplementing it.

Reviewed By: ot

Differential Revision: D7769745

fbshipit-source-id: 3cb7bf9908cc6e93c7d19ace9a91c69ba14cdfae

Summary:
OpenSSL 1.1.0 renamed and deprecated X509_CRL_get_lastUpdate -> X509_CRL_get0_lastUpdate
along with X509_CRL_get_nextUpdate -> X509_CRL_get0_nextUpdate

Reviewed By: ngoyal, anirudhvr, Orvid

Differential Revision: D7782339

fbshipit-source-id: 63f04284bb54da87d4235a02890107db8abaa4b4

Summary:
This was exposed by the latest clang with -Wreturn-std-move enabled:
```lang=bash
folly/FBString.h:2487:12: error: local variable 'rhs' will be copied despite being returned by name [-Werror,-Wreturn-std-move]
    return rhs;
           ^~~
folly/test/FBStringTest.cpp:1294:23: note: in instantiation of function template specialization 'folly::operator+<char, std::char_traits<char>, std::allocator<char>, folly::fbstring_core<char> >' requested here
    auto test1 = '\0' + std::move(s1);
                      ^
folly/FBString.h:2487:12: note: call 'std::move' explicitly to avoid copying
    return rhs;
           ^~~
           std::move(rhs)
2 errors generated.
```

Reviewed By: Orvid

Differential Revision: D7776805

fbshipit-source-id: f11ae5a1fc416b8838b8ea74d7f6b488f07cab38

Summary: Need to also allow calling this function with a writeLock.

Reviewed By: magedm

Differential Revision: D7477326

fbshipit-source-id: 403e2667a3f77be4c1d7d06dbd5f36218a659abc

Summary: The test is intended to verify the handling of trailing space.

Reviewed By: yfeldblum

Differential Revision: D7761229

fbshipit-source-id: 0196f57e6c76562562ef1b724f6dff1c7bfd5d81

Summary:
Rename folly/Logging.h to folly/GLog.h.  This header primarily exists to just
include <glog/logging.h>, and it also defines a single `FB_LOG_EVERY_MS()`
macro.

I plan to move the folly/experimental/logging/ directory to folly/logging/
soon, and I want to avoid confusing between this `Logging.h` header and the
separate `folly/logging/` code.

Reviewed By: yfeldblum

Differential Revision: D7754543

fbshipit-source-id: c91b8016d303cd0fae9e688e8782b22d095a6554

Summary:
D7642870 accidentally broke linking of folly when libunwind is available.
It change the code to use the contents of `${FOLLY_LINK_LIBRARIES}` in
folly-deps.cmake, but libunwind was added to `${FOLLY_LINK_LIBRARIES}` after
folly-deps.cmake was included, in FollyConfigChecks.cmake.

This moves the check for libunwind to folly-deps.cmake to fix this issue.  All
of the other checks for external libraries are already in folly-deps.cmake.

Reviewed By: yfeldblum

Differential Revision: D7764762

fbshipit-source-id: 922459a7eefcbd92d3d77c02e9c215bb1a5467cc

Summary: This allows using a keep-alive token in places where Executor* was previously used.

Reviewed By: yfeldblum

Differential Revision: D7751516

fbshipit-source-id: af2cb31191a78306439408dbee78dcd923492e30

Summary:
`PRETTY_TIME_HMS` extends `PRETTY_TIME` by adding additional minutes
and hours units which are more useful for human-reporting of time intervals.

Reviewed By: yfeldblum

Differential Revision: D7762524

fbshipit-source-id: 881936916db182c163a3df14196f4f11fb649527

Summary: [Folly] Avoid using gmock private macros - instead, use only the public interface.

Reviewed By: knekritz

Differential Revision: D7752463

fbshipit-source-id: 625465e7ec93613869e259fe1fe0b08aee7bb7d0

Summary:
This diff adds a method to calculate the amount of memory allocated by F14
sets. It mimics the node structure in `std::unordered_map` to calculate the
results. For certain keys and hashers, the libstdc++ implementation of
`std::unordered_map` caches a hash code in the node. libcpp seems to do this
for everything.

https://github.com/gcc-mirror/gcc/blob/9ce5a00d2d3b8b107cb1ca0e23bf1e31a095f9b6/libstdc%2B%2B-v3/include/bits/hashtable.h#L45-L49
https://github.com/llvm-mirror/libcxx/blob/58bcf28c63e0cf2ee5828e7811829c98bd244dda/include/__hash_table#L117

Depends on D7715573.

Reviewed By: nbronson

Differential Revision: D7728281

fbshipit-source-id: 0aa3ab60c746d3ab6bdb7c879f2f987110e0329d

Summary: Because not everyone is at C++17 yet.

Reviewed By: yfeldblum

Differential Revision: D7751672

fbshipit-source-id: bcca4d4da67d56be0217a940144977f1cc98e5a1

Summary: Add the currency tests to the CMake build so they can be built in open-source.

Reviewed By: yfeldblum

Differential Revision: D7750783

fbshipit-source-id: a6e7f9490e0b88bcfab8b2aa706e1504f2a28c66

Summary:
This looked like a copypasta error. Since there is no duration passed
in, there is no notion of timeout.

Reviewed By: shixiao, Orvid

Differential Revision: D7747574

fbshipit-source-id: 279992d237dd0924ea0be9deafab94c1aef48838

Summary: [Folly] Fix autotools build afte removing `folly/Optional.cpp`.

Reviewed By: akrieger

Differential Revision: D7737170

fbshipit-source-id: 1a9286f240bf5a15ee08b707b69377f8d3cfdb48

Summary:
OpenSSL 1.1.0 uses a fiber-based (makecontext/swapcontext) API to do
asynchronous operations. When some operation deep inside the stack calls
ASYNC_pause_job, SSL_accept returns -1 with error SSL_ERROR_WANT_ASYNC.
OpenSSL chose to use fds to wait on, so after SSL_accept returns, we create an
AsyncPipeReader to restart SSL_accept when the pipe becomes readable, which is our
indication that the async job processing has finished.

Also implemented a test to kick off an async job in a different thread that creates a pipe
and gives the read end back to the SSL* before calling ASYNC_pause_job

Reviewed By: yfeldblum

Differential Revision: D5977514

fbshipit-source-id: 3aba2e45b9357dc28cf7cf785654072f8ba8dd65

Summary: On top of the recent/big EventBaseLoopController cleanup away from most EventBase internal, this is unecessary

Reviewed By: andriigrynenko

Differential Revision: D7734236

fbshipit-source-id: df38cc30fc52df929f096fb878bc1a4b6894850a

Summary:
We don't have a way to get the metadata associated with a given setting name
from outside. This is useful to know the expected type associated with a
given setting name.

Reviewed By: alikhtarov

Differential Revision: D7721340

fbshipit-source-id: e9ad07dd03c172f6f2d4bde5164614ca987c4fd8

Summary: [Folly] Use `throw_exception` in `Optional`, which also respects all stated reasons why the `throw` statement is moved to a separate `.cpp` - to outline it and to permit replacement of its implementation with a call to `std::terminate`.

Reviewed By: akrieger

Differential Revision: D7728129

fbshipit-source-id: 0539f9d16a719b52f5a81b13b5d2ce2b61d36de0

Summary:
The sorting approach used in TDigest is inefficient because it is not leveraging the fact that there are k sorted subarrays. This diff leverages inplace_merge to improve performance.

The cost of merging k digests of size m used to be O(km * log(km)). It is now O(km * log(k)).

Reviewed By: anakryiko

Differential Revision: D7690143

fbshipit-source-id: 1307db153b3cae0bb952d4b872aede8c40ce292c

Summary:
The issue is that std::swap must have the same type for both parameters but the member .swap() for PolyVal takes Poly and then uses std::swap(*this, that).

the fix uses static_cast to change the Poly to a PolyVal for std::swap

Reviewed By: ericniebler

Differential Revision: D7730948

fbshipit-source-id: 8dd93fc3c86b87938a7c0c12ccb3b5209a593730

Summary: Further performance improvements to TDigest by diverging from the algorithm in the paper slightly, but in a manner that does not impact the results at all.

Reviewed By: anakryiko

Differential Revision: D7687476

fbshipit-source-id: f71884b0fb21c9e78418643b82b099b01e96e4c9

Summary:
[Folly] Fix build failures in `folly/io/async/test/AsyncUDPSocketTest.cpp`, which uses private gmock macros to try to override base-class member functions marked `noexcept`.

Using private macros belonging to another library is not the way to go.

Reviewed By: siyengar

Differential Revision: D7728285

fbshipit-source-id: 84c96826f25679dfb8dd0ec5e5985c3cc19f6e3d

Summary:
I suspect the algorithm in the tdigest paper is slightly off. Instead of setting boundaries at k = 1, 2, 3...d, it sets boundaries at k_last_elem + 1. This results in two issues:

1) It is possible to have more than d elements in the digest. Now, that is no longer possible, and we can properly reserve the right number of elements.
2) Additional floating point operations are computed than necessary.

Reviewed By: anakryiko

Differential Revision: D7654147

fbshipit-source-id: 131184d456353a9d936c4ed385e2b5e75d468676

Reviewed By: yfeldblum

Differential Revision: D7726522

fbshipit-source-id: fa5ad9fc29152b52c5256849c2822885acd49c23

Summary: [Folly] Cut dead reference to `executorLock_` in Futures test - this field was recently removed.

Reviewed By: LeeHowes

Differential Revision: D7725446

fbshipit-source-id: a522b66da77bbefeb69970bee20feea46dcc72a5

Summary:
`folly::lock()` is a deadlock safe way to acquire write
locks on many lockables or `folly::Synchronized` objects

```
lock(folly::wlock(one), folly::rlock(two), folly::wlock(three));
```

This executes the deadlock avoidance algorithm on a write lock for `one` and
`three` and a read lock for `two`.  ADL lookup is done for the `lock()`
function.

It can also work on arbitrary lockables and performs better than both
`std::lock()` and acquiring the mutexes in order

```
folly::lock(one, two, three);
```

There is a big performance improvement compared to simply acquiring locks
in the same order in the presence of contention.  The backoff algorithm tries
to adjust to contention and block on the mutex that it thinks is the best fit.

Benchmarks look promising

```
============================================================================
folly/test/SynchronizedBenchmark.cpp            relative  time/iter  iters/s
============================================================================
ThreeThreadsPathologicalFollyLock                            3.81us  262.24K
ThreeThreadsPathologicalStdLock                              5.34us  187.28K
ThreeThreadsPathologicalOrdered                              6.36us  157.28K
ThreeThreadsPathologicalCarefullyOrdered                     4.21us  237.29K
----------------------------------------------------------------------------
TwoThreadsTwoMutexesOrdered                                260.87ns    3.83M
TwoThreadsTwoMutexesSmart                                  161.28ns    6.20M
TwoThreadsTwoMutexesPersistent                             226.25ns    4.42M
----------------------------------------------------------------------------
TwoThreadsFourMutexesOrdered                               196.01ns    5.10M
TwoThreadsFourMutexesSmart                                 196.73ns    5.08M
TwoThreadsFourMutexesPersistent                            201.70ns    4.96M
----------------------------------------------------------------------------
TwoThreadsEightMutexesOrdered                              195.76ns    5.11M
TwoThreadsEightMutexesSmart                                187.90ns    5.32M
TwoThreadsEightMutexesPersistent                           199.21ns    5.02M
----------------------------------------------------------------------------
TwoThreadsSixteenMutexesOrdered                            203.91ns    4.90M
TwoThreadsSixteenMutexesSmart                              196.30ns    5.09M
TwoThreadsSixteenMutexesPersistent                         230.64ns    4.34M
----------------------------------------------------------------------------
FourThreadsTwoMutexesOrdered                               814.98ns    1.23M
FourThreadsTwoMutexesSmart                                 559.79ns    1.79M
FourThreadsTwoMutexesPersistent                            520.90ns    1.92M
----------------------------------------------------------------------------
FourThreadsFourMutexesOrdered                              456.04ns    2.19M
FourThreadsFourMutexesSmart                                391.69ns    2.55M
FourThreadsFourMutexesPersistent                           414.56ns    2.41M
----------------------------------------------------------------------------
FourThreadsEightMutexesOrdered                             392.20ns    2.55M
FourThreadsEightMutexesSmart                               277.89ns    3.60M
FourThreadsEightMutexesPersistent                          301.98ns    3.31M
----------------------------------------------------------------------------
FourThreadsSixteenMutexesOrdered                           356.36ns    2.81M
FourThreadsSixteenMutexesSmart                             291.40ns    3.43M
FourThreadsSixteenMutexesPersistent                        292.23ns    3.42M
----------------------------------------------------------------------------
EightThreadsTwoMutexesOrdered                                1.58us  634.85K
EightThreadsTwoMutexesSmart                                  1.58us  634.85K
EightThreadsTwoMutexesPersistent                             1.56us  639.93K
----------------------------------------------------------------------------
EightThreadsFourMutexesOrdered                               1.33us  753.45K
EightThreadsFourMutexesSmart                               794.36ns  936.34K
EightThreadsFourMutexesPersistent                          831.68ns    1.21M
----------------------------------------------------------------------------
EightThreadsEightMutexesOrdered                            791.52ns    1.26M
EightThreadsEightMutexesSmart                              548.05ns    1.51M
EightThreadsEightMutexesPersistent                         563.14ns    2.78M
----------------------------------------------------------------------------
EightThreadsSixteenMutexesOrdered                          785.40ns    2.11M
EightThreadsSixteenMutexesSmart                            541.27ns    1.60M
EightThreadsSixteenMutexesPersistent                       673.49ns    1.79M
----------------------------------------------------------------------------
SixteenThreadsTwoMutexesOrdered                              1.98us  505.83K
SixteenThreadsTwoMutexesSmart                                1.85us  541.06K
SixteenThreadsTwoMutexesPersistent                           3.13us  319.53K
----------------------------------------------------------------------------
SixteenThreadsFourMutexesOrdered                             2.46us  407.07K
SixteenThreadsFourMutexesSmart                               1.68us  594.47K
SixteenThreadsFourMutexesPersistent                          1.62us  617.22K
----------------------------------------------------------------------------
SixteenThreadsEightMutexesOrdered                            1.67us  597.45K
SixteenThreadsEightMutexesSmart                              1.62us  616.83K
SixteenThreadsEightMutexesPersistent                         1.57us  637.50K
----------------------------------------------------------------------------
SixteenThreadsSixteenMutexesOrdered                          1.20us  829.93K
SixteenThreadsSixteenMutexesSmart                            1.32us  757.03K
SixteenThreadsSixteenMutexesPersistent                       1.38us  726.75K
============================================================================
```

Reviewed By: djwatson

Differential Revision: D6673876

fbshipit-source-id: b57fdafb8fc2a42c74dc0279c051cc62976a4e07

Summary: [Folly] Avoid magic macros in Futures `FSM` - just use normal C++ types and functions instead.

Reviewed By: LeeHowes

Differential Revision: D7725582

fbshipit-source-id: 822e4ca6391a37dc4007833c975fe283cfe5105e

Summary: [Folly] Rename function to `tryUpdateState` in Futures `FSM` for clarity.

Reviewed By: LeeHowes

Differential Revision: D7725949

fbshipit-source-id: ccda21d990dbedfc4d0b86ab7cfb8eb68d93e429

Summary: [Folly] Use RAII `std::lock_guard` pattern in Futures `FSM` and `Core`.

Reviewed By: LeeHowes

Differential Revision: D7722808

fbshipit-source-id: e8a0d0ec1fee05cd723411f7b07f520dd56cdf22

Summary: [Folly] Let `Future::ensure` and `Future::onTimeout` invoke forwarded callbacks, just as `Future::then` and other callbacks are invoked.

Reviewed By: LeeHowes

Differential Revision: D7722762

fbshipit-source-id: 52b5fb6a9247d99718de808b0d28abba7dacdbd6

Summary:
Currently each of the lock proxies have distinct types and they are not
convertible from one to the other, for example the code below does not work

```
auto wlock = sync.wlock();
wlock.unlock();

auto ulock = sync.ulock();
wlock = ulock.moveFromUpgradeToWrite();
```

Reviewed By: yfeldblum

Differential Revision: D7658256

fbshipit-source-id: 1746a67193fc712fd4d4ff2ce41aa295f998211e

Summary: [Folly] Use exchange in `folly/Synchronized.h` as an example and to make the code there slightly shorter.

Reviewed By: aary

Differential Revision: D7722730

fbshipit-source-id: c594fc96cff11781b60a3848a860454bcf21c3ca

Summary: [Folly] Backport `std::exchange` to `folly/Utility.h`.

Reviewed By: aary

Differential Revision: D7722731

fbshipit-source-id: a4a68bfb9ec8b356b77f4a73bdadb7f2807d517f

Summary:
There was some code that optionally acquired a lock in a shared or exclusive
manner based on whether those methods were available for the mutex or not.
This was not used anywhere

Reviewed By: yfeldblum

Differential Revision: D7722906

fbshipit-source-id: b749527c13a1d980134cc23dea586c83a0b65e91

Reviewed By: yfeldblum

Differential Revision: D7721840

fbshipit-source-id: f816ba58da290e05d257447c42472d5fa99915e3

Summary:
As per title.
Closes https://github.com/facebook/folly/pull/827

Reviewed By: Orvid

Differential Revision: D7721855

Pulled By: yfeldblum

fbshipit-source-id: fe335dcfa83b4db04616e33e353fea52ebb2bbf2