Summary:
The documentation for folly::to<double>()'s handling of unparseable inputs (including "") is incorrect.  Additionally, the documentation does not document to<double>()'s handling of the inputs "NaN", "-NaN", "inf", "infinity", "-inf", and "-infinity".

This corrects the documentation.

See https://github.com/facebook/folly/blob/3272dfdbe243e0ac02acca1dd82bc391d1da079a/folly/docs/Conv.md under the heading "Parsing floating-point types" for the incorrect documentation as rendered.

Reviewed By: yfeldblum

Differential Revision: D5367656

fbshipit-source-id: 22b38e2bb85d2e647975798360ead39eed6caae8

Summary: This avoids having exceptions occur while constructing hashtables.

Reviewed By: ot, yfeldblum

Differential Revision: D5384419

fbshipit-source-id: ba2de8cffa46df550bdc62abbe529801249e45cd

Summary:
Should now work on GCC-compatible compilers, and all other compilers which don't attempt any inter-TU optimizations.

Moved out of Utility.h because it now requires a supporting .cpp file and some clients presume that Utility.h can be used header-only.

Reviewed By: ot

Differential Revision: D5381042

fbshipit-source-id: 7e954fed47de4386c85d46a61d56a8fe7fc516f4

Summary: This reverts commit bc725838dc7f62d030c7e68bc6d229042df2b46c

Differential Revision: D5393697

fbshipit-source-id: 4b9ef1e733b0ad73e6deea7ac8a52dfe785b4f2b

Summary:
This revision adds a helper method in folly/Checksum.h, that returns the same crc32 value as php's built-in implementationa and boost::crc_32_type.

folly's default implementation only differs from the final xor (with 0xFFFFFFFF for boost and php, 0 for folly), which is added here.

Reviewed By: djwatson

Differential Revision: D5396671

fbshipit-source-id: 14874af2d5a80408c772875142de6e340ce01038

Summary: `__gnu_cxx::sfmt19937` is 3.5x faster than `std::mt19937` according to the benchmark.

Reviewed By: yfeldblum

Differential Revision: D5393697

fbshipit-source-id: bc725838dc7f62d030c7e68bc6d229042df2b46c

Summary: The fiber command can now be run on a value of type folly::fibers::Fiber or a value of type folly::fibers::Fiber*

Reviewed By: andriigrynenko

Differential Revision: D5393491

fbshipit-source-id: 1f48e08288f75c59852c939062db616eb06cea73

Summary:
`Baton` is more lightweight than a mutex+condition variable, and the code is much simpler. This was actually the original implementation, but the dependency had to be dropped because `Baton` was unsupported on some architectures. That is not a problem anymore.

Also reorganize the includes to follow the conventions.

Reviewed By: andriigrynenko, yfeldblum

Differential Revision: D5396631

fbshipit-source-id: d782cf271eb35723aaeb3c372e1c1dafeaaf0f0a

Summary:
The function `setCipherList` seems to forget to update the data member
`providedCipherString_`. This diff updates `providedCiphersString_` at
a single place `setCiphersOrThrow()`, and adds two test cases to make
sure the derived `SSL*` uses the desired set of ciphers.

Reviewed By: yfeldblum

Differential Revision: D5372758

fbshipit-source-id: 8144ab3bc518b2b9fa8090af62f3bd6475bbbece

Summary:
[Folly] Compute masks in `IPAddressV6`.

At runtime, instead of storing a 2Kb masks array in the binary.

Reviewed By: WillerZ, ot

Differential Revision: D5369901

fbshipit-source-id: 031a4eeda1670021236d8ab97f6e85e753675ae5

Summary: Add a fiber_address(fiberManager, index) function so that you can programatically get the address of a given fiber in a fiberManager

Reviewed By: andriigrynenko

Differential Revision: D5377605

fbshipit-source-id: b9504f7d253e8f702e9329c6f08ff406d4296a6e

Summary: refs hhvm/packaging#128

Reviewed By: anirudhvr

Differential Revision: D5380271

fbshipit-source-id: 1cc206d9970b843c3582556096f3ceabeb8d01f6

Summary: Making the exception text more useful by adding getnameinfo's error code and the v6 scope id

Reviewed By: yangchi

Differential Revision: D5389137

fbshipit-source-id: e6b9b4edd7dd1859e0ed4d784b2f89a60a701955

Summary:
[Folly] In-place construction for `Future`.

Using `in_place` as the first argument. Avoid constructing a contained object and then moving it into the `Future`, which may be more expensive, by providing an unambiguous way to specify perfect forwarding.

And a matching overload of `makeFuture` for no particularly good reason.

Differential Revision: D5362324

fbshipit-source-id: e612965f34ed0fae5fac17db631f7eab9984c696

Summary: as in title

Reviewed By: yfeldblum

Differential Revision: D5382995

fbshipit-source-id: 87534e6092f167399943287182ec61ae21e608c6

Summary:
`constexpr` All The Things! Although only very recent versions of modern compilers support this, FunctionRef can and should be `constexpr` (demonstration here: https://godbolt.org/g/NJ72RG).

This change also changes the `FunctionRef` constructor such that it no longer participates in overload resolution if the argument is not callable with the specified arguments. In addition, it perfectly forwards the callable object such that if it was an rvalue when it was passed to the constructor, it will be invoked as an rvalue in `operator()`.

Reviewed By: yfeldblum

Differential Revision: D5366720

fbshipit-source-id: bc64053213478aab5a5bd5950c7b2d6f364d86bd

Summary:
Provides a `make_mock` interface to `folly::LeakySingleton` for unit test
mocking.

Reviewed By: andriigrynenko

Differential Revision: D5382003

fbshipit-source-id: 9ab81dd64703f4f02772bfb8c85e020680abcc85

Summary: Because MSVC is not happy about how it's written now.

Reviewed By: yfeldblum

Differential Revision: D5378740

fbshipit-source-id: 8b77d1a05da75b331e0cb72bd0ad859b89e54b36

Summary: OpenSSL 1.1.0 drops support for SSLv2, and in doing so also removes the define that user-code used to guard on whether SSLv2 was supported. This adds the define to the portability header to indicate SSLv2 is not supported.

Reviewed By: anirudhvr

Differential Revision: D5376869

fbshipit-source-id: 04708db138dc13e7747cfff582f4cfed291648b3

Summary: Backport C++17's `std::launder`.

Reviewed By: yfeldblum, ot

Differential Revision: D5370531

fbshipit-source-id: b7cc6701d082b6c4855fa77bb644e151ce882deb

Summary:
The TestDoubleWidthTooBig test was performing an exact equality check on
two double values. This equality check fails when run on 32-bit
platforms.

Replace the EXPECT_EQ() check with EXPECT_NEAR(), and simply check that
the two values do not differ by more than 1e-14.

Reviewed By: Orvid

Differential Revision: D652767

fbshipit-source-id: 7bf7ed560a4180a2e2d07a6050d1df18e18d1eea

Summary:
Update LogLevel's operator+() to consist only of a single return statement.
This is required for pre-C++14 compiler support.

Reviewed By: yfeldblum

Differential Revision: D5368256

fbshipit-source-id: 9ecbcde5edd1d0b3e7580d6263ad926e44908219

Summary:
[Folly] `Promise<T>::makeEmpty()` and `Future<T>::makeEmpty()`.

These can currently be done by creating, and then moving away from, regular promises and futures. But that allocates; this is semantically equivalent but more efficient.

Differential Revision: D5368339

fbshipit-source-id: de054cfc75c701c5d39aac64d9a2949cd34b1896

Summary:
Avoid this false positive from clang:

  folly/futures/detail/Core.h:369:15: error: variable 'priority' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]

Reviewed By: yfeldblum

Differential Revision: D5369916

fbshipit-source-id: 49649417d1b799cc3945cba456b42ab438ad2ddc

Summary: [Folly] Apply clang-format to `folly/stats/`.

Reviewed By: Orvid

Differential Revision: D5366745

fbshipit-source-id: 3b7419d4ab4c6203693603722cd8e707741d3953

Summary: [Folly] Apply `clang-format` to `folly/ssl/`.

Reviewed By: Orvid

Differential Revision: D5366760

fbshipit-source-id: ad4ec0570050f80d69c78626906e18b5892a999f

Summary: [Folly] Apply `clang-format` to `folly/concurrency/`.

Reviewed By: Orvid

Differential Revision: D5366946

fbshipit-source-id: 2c9de7c4d8534e02c367fd235fb1ea943ba0539e

Summary:
[Folly] Extract the namespace choice in `FBString.h`.

The funny `namespace` bits confuse `clang-format`, so let us remove the confusion.

Reviewed By: ot, Orvid

Differential Revision: D5367299

fbshipit-source-id: efca65fecc70076829c14e31a835bc91f3efb4a4

Summary: [Folly] Apply `clang-format` to `folly/io/` (namespace).

Reviewed By: Orvid, terrelln

Differential Revision: D5366477

fbshipit-source-id: b4efcdc66c62885f5574b2940e5138590710deae

Summary: The fix for this didn't get made before the commit landed.

Reviewed By: yfeldblum

Differential Revision: D5367593

fbshipit-source-id: 4ed9c781121d1b23db11d75d0f8d017d1d8663d9

Summary: When I moved the change internally, I failed to add the `#include` that was required :(

Reviewed By: yfeldblum

Differential Revision: D5366037

fbshipit-source-id: 7ddf8fc0b7a0468d0831e886d8025c1893f7f8ae

Summary: `constexpr` All The Things!

Reviewed By: Orvid

Differential Revision: D5364910

fbshipit-source-id: 11abeb8adc38aef3ac4f2596ecf0f533b9e74203

Summary:
[Folly] For `futures::retrying`, detect policy type using `std::result_of`.

`FOLLY_CREATE_HAS_MEMBER_FN_TRAITS` does not work in all cases. For example, it does not work with inherited members.

And it is not really what we want, anyway, which is to dispatch based on the result type of invoking the policy with a particular set of arguments. We can do that more directly using `std::result_of`. And if we did not have `std::result_of`, then we could do that with SFINAE directly.

Reviewed By: WillerZ

Differential Revision: D5361808

fbshipit-source-id: 23f969dfd6dbaaa944dc2288e70c3ea11d3398f0

Summary:
Allows you to construct a `Future<A>` from a `Future<B>` if A can be constructed from `B&&`.

The constructor is `implicit` if and only if `B&&` is convertible to `A`.

This is the same philosophy as Optional, and has the same use-cases.

Reviewed By: yfeldblum

Differential Revision: D5264185

fbshipit-source-id: e2fae373ab549c186a69dc5f4e32481ef7b11bba

Summary: There is no difference, as the statements are already implicitly volatile.

Reviewed By: yfeldblum

Differential Revision: D5363491

fbshipit-source-id: ab5bb878f5ca72aa0de96f82e345213729c071e2

Summary:
[Folly] In-place construction for `Try`.

Using `in_place` as the first argumenbt. Avoid move operations.

Reviewed By: Orvid

Differential Revision: D5362568

fbshipit-source-id: 5c2aaf5dba1253c59e384940add411f0f2b570b2

Summary:
[Folly] In-place construction for `Optional`.

Using `in_place` as the first argument. Avoid move operations.

Reviewed By: Orvid, ot

Differential Revision: D5362563

fbshipit-source-id: 771db2556842d5dec35d1bf2ad6c23358a417d54

Summary:
[Folly] Move `in_place` and friends to `Utility.h`.

Document that they are backports from C++17.

Reviewed By: Orvid

Differential Revision: D5362364

fbshipit-source-id: 495cb7f339fc558f20d89100c141fc7a243239d5

Summary:
[Folly] Remove `construct_in_place`.

It is an alias for `in_place`, and unnecessary.

Reviewed By: Orvid

Differential Revision: D5362354

fbshipit-source-id: 39ce07bad87185e506fe7d780789b78060008182

Summary:
[Folly] Disambiguate the various `in_place` overloads, following C++17.

Forwarding `folly::in_place` is ambiguous because there are multiple overloads and we depend on deduction to choose the correct overload. For example:

```lang=c++
enum struct Err {};
Expected<Expected<int, Err>, Err> val(in_place, in_place, 3); // fails to compile
```

So we must disambiguate the three overloads: the default, the typed, and the indexed.

C++17 defines `std::in_place`, `std::in_place_type<typename>`, and `std::in_place_index<std::size_t>`. Let us mimic that exactly, so that it becomes trivial to swap out our implementations for the standard implementations once we jump to C++17.

Reviewed By: Orvid

Differential Revision: D5362339

fbshipit-source-id: d4012b01796390e74d8c14cdf68af70102608039