Summary:
Class template that wraps a reference to an rvalue. Similar to std::reference_wrapper but with three important differences:
1) folly::rvalue_reference_wrappers can only be moved, not copied;
2) the get() function and the conversion-to-T operator are destructive and not const, they invalidate the wrapper;
3) the constructor-from-T is explicit.
These restrictions are designed to make it harder to accidentally create a a dangling rvalue reference, or to use an rvalue reference multiple times. (Using an rvalue reference typically implies invalidation of the target object, such as move-assignment to another object.)

Reviewed By: yfeldblum

Differential Revision: D4931483

fbshipit-source-id: 68453553bf4656ec41976699669a4491fcab79c9

Summary:
`cpuid` uses all of `eax`, `ebx`, `ecx`, `edx` for output, but we
aren't providing such information to GCC in a couple of cases, which might
result in incorrect code being produced;

GCC (unlike clang) doesn't allow the same register to appear both in input and
clobber list, so put `eax` into output list where required.

Reviewed By: ot, lbrandy

Differential Revision: D4961841

fbshipit-source-id: 07ca1977373496bfd794d3b0c8a4ba21333820e4

Summary: There's a gotcha case for IOBufQueue::split when  n==0, it will then return an unique_ptr wrapping a nullptr, which many call sites do not expect.

Reviewed By: meyering

Differential Revision: D4868228

fbshipit-source-id: 418256dba8ca3bcfbae420b6099baa240055b9bb

Summary: Added a lock holder with deferred option for cases where the caller may want to call try_lock() later.

Reviewed By: djwatson

Differential Revision: D4949736

fbshipit-source-id: 31e0dc349dc3af9d04a33878e26cef1e48cce674

Summary: [Folly] Casing consistency for `exception_wrapper::throw_exception`.

Reviewed By: Orvid

Differential Revision: D4944818

fbshipit-source-id: 72056fb24ab6362e9a0319f73b5bbf8c92d658ca

Summary: Pattern matching like functionality for boost::vairant. See unittests for usage examples.

Reviewed By: yfeldblum, ericniebler

Differential Revision: D4851133

fbshipit-source-id: cda7dc766dac5870bcc4ab1859de0e4e7f0a6599

Summary:
1. `emplace_back()` is broken when there are at least two arguments and one is a reference to inside the vector. See the `ForwardingEmplaceInsideVector` test.
2. Only `push_back(value_type&&)` did exponential growth, every other function grew linearly. The bug is hidden inside of facebook because `goodMallocSize()` grows fast enough to not be horribly slow. When not using jemalloc, it will grow one element at a time.
3. `push_back(value_type const& t)` performed a copy and a move on `t` when `size() == capacity()`. Remove the extra move.

Fixes https://github.com/facebook/folly/issues/541.

Reviewed By: luciang

Differential Revision: D4875084

fbshipit-source-id: eefa76028c6bfd9d7c73af65e8bb9d4baf49b8cb

Summary:
Currently, contbuild has a blanket TSAN suppression for folly.
Fix PicoSpinLock instead

This should fix TSAN errors as an alternative to D4781776

Some of the tests even had TSAN errors, fixed those.

Reviewed By: davidtgoldblatt

Differential Revision: D4795284

fbshipit-source-id: 9f0fc6868399da2f86be355ce3c081990260a649

Summary: virtual classes currently don't work in hazard pointers, and get incorrectly reclaimed.

Reviewed By: magedm

Differential Revision: D4951584

fbshipit-source-id: 8200df6bb8d500af2e89086edf7835d4fb90b6a2

Summary: They allow for assignments that make no sense, so make it impossible to do so.

Reviewed By: yfeldblum

Differential Revision: D4919606

fbshipit-source-id: 24d8e036eff33a8c6def4672c0d098f0edd5c5b3

Summary:
Improve concurrency guards for `setSSLLockTypes` and `isSSLLockDisabled` by using initMutex.  Also verify that openssl has been initialized w/ DCHECK in isSSLLockDisabled.

We also add a method to do the setting of locks and initialization in one shot.

Reviewed By: knekritz

Differential Revision: D4937242

fbshipit-source-id: 308f516c17485281604d4322954c09beb58688e2

Reviewed By: vitaut

Differential Revision: D4940976

fbshipit-source-id: 0c4ebf8f358e6f54a7b5e81f2e73649b030006c9

Summary:
`folly::setThreadName` is neither performance critical, nor (after this diff) is it a template, so exposing the mess that is its implementation to the world isn't worth it.
The implementation is expected to get even more messy as I add support for getting the current thread's name, and eventually also add support for Windows as well.

This also required exposing whether the current platform supports setting the name of the current or other threads.

Reviewed By: yfeldblum

Differential Revision: D4942401

fbshipit-source-id: 0e3be203995fa6ed667a5fd28dac7ba7fa49d683

Summary: Using `#ifndef __ANDROID__` does not necessarily handle all cases of gating the wchar tests

Reviewed By: Orvid

Differential Revision: D4938634

fbshipit-source-id: a2184e20b8c382e5a34947c029f7e3746272b407

Summary: We set the actual locks on initialization, so attempting to change locks after had no affect, other than making isSSLLockDisabled() report incorrect information.

Reviewed By: yfeldblum

Differential Revision: D4935475

fbshipit-source-id: 7b80cd530801c925ade769163579b86b1a8f0027

Summary: ^^^

Reviewed By: yangchi

Differential Revision: D4934455

fbshipit-source-id: babf56f4705ae06f46b694df3f2890d4b9506861

Summary: The traitsLength call in the basic_fbstring constructor is returning a bad value.

Reviewed By: Orvid

Differential Revision: D4930106

fbshipit-source-id: 556a61c4496c2af91cb70db6d62cdc7e915edd55

Summary: It was changed to a `void*` previously due to an ICE in GCC 4.7. GCC 4.7 hasn't been supported in quite a while, and newer versions of GCC don't crash, so it's time to switch it back to `nullptr_t`.

Reviewed By: yfeldblum

Differential Revision: D4917389

fbshipit-source-id: fc48642026c7e3aaeadef27bb949f70648c2312c

Reviewed By: Orvid

Differential Revision: D4921738

fbshipit-source-id: 69848cda3638fca4ead73dcc9949af0f600f33bb

Summary:
1. Restrict EventBaseLocal API to only be used from EventBase thread to avoid extra locking.
2. Make sure objects stored in EventBaseLocal are destroyed in EventBase thread.

Reviewed By: yfeldblum

Differential Revision: D4918282

fbshipit-source-id: b7cb4c2b62fef85a9b1d796fa71af8af9087479d

Summary:
This change removes the unpackHack function from small_vector, which was blocking ##-Waddress-of-packed-member## from being enabled. The fix is split the pointer-getting non-const ##getCapacity## into a normal getter and setter.

(lithium is flakey, according to continuous, and is push-blocking)

Reviewed By: yfeldblum

Differential Revision: D4918188

fbshipit-source-id: 435e030ad659f5dc9c42d90e9bfee9ca564a120a

Summary:
Faced this problem on Ubuntu 14.04.4 LTS

```
configure:16581: error: possibly undefined macro: AC_MSG_NOTICE
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
autoreconf: /usr/bin/autoconf failed with exit status: 1
```
Fixed with `apt-get install pkg-config`
Closes https://github.com/facebook/folly/pull/579

Reviewed By: yfeldblum

Differential Revision: D4886216

Pulled By: Orvid

fbshipit-source-id: 88159b70bfcf62d01bef502b3a5da6c9d81499bc

Summary:
Any pair of read-compatible (same type, same traits) basic_strings (`basic_fbstring` or `std::basic_string`) can now be compared to each other with the `==`, `!=`, `<`, `>`, `<=`, and `>=` operators.

If you have a C++14 environment this allows you to use the heterogeneous comparison lookup methods from N3657: you can query containers which store either string type with either string type efficiently.

Reviewed By: yfeldblum, ot

Differential Revision: D4905697

fbshipit-source-id: 2ea976ebf40af45d64c1d8c1c08847feb3b9db68

Summary:
portabilty/String.h defines functions for Windows which
are provided by <strings.h> on other platforms, but doesn't include
<strings.h> in that case.

Reviewed By: Orvid

Differential Revision: D4908770

fbshipit-source-id: b3326f78509c2aa1acb9c9279f01537b0a243400

Summary: On some platforms (iPhone 5C at least), ObjC/Objc++ BOOL is really signed char.  There is code which expects this to be a boolean when converted to dynamic (and then to JSON and into JS), but the old code treated it as a number.  This makes such code (like [mobileConfig getBool:]) fail to compile, so the developer needs to resolve the ambiguity one way or the other.

Reviewed By: yfeldblum

Differential Revision: D4648133

fbshipit-source-id: 76ece7803a1e966dca08bdb857af7990035544a0

Reviewed By: yfeldblum

Differential Revision: D4898404

fbshipit-source-id: 82256ae3dcd76444dc1b192d3bb6d50f142cee81

Summary: According to [clang documentation](http://clang.llvm.org/docs/AttributeReference.html#no-sanitize-clang-no-sanitize), the format is incorrect. This results unit-test failure with ubsan.

Reviewed By: yfeldblum

Differential Revision: D4901777

fbshipit-source-id: e9d012366c5e1911632e47fa4fb690820b761fc3

Summary:
Modified FC stats. Added number of sessions and removed the number of out-of-memory record allocations.
Removed locking from reading stats to avoid deadlock if the lock is already held. Reading stats now assumes exclusive access.

Reviewed By: djwatson

Differential Revision: D4857132

fbshipit-source-id: 81e4f25040af3691f3e82fe3794ee72c7ff53a99

Summary: The pthread_t overload will die in the next diff, but cleanup needs to be done first.

Reviewed By: yfeldblum

Differential Revision: D4900830

fbshipit-source-id: d0cd56c5bd7fe22904f631c0cc64dff66448127c

Summary: This assumes I understand strict-aliasing rules correctly.

Reviewed By: yfeldblum

Differential Revision: D4900118

fbshipit-source-id: edba535d3ba799ac665d3f859dc4154b2c1b22cb

Summary: We should be able to reset error message callback in AsyncSocket evein if the socket is closed yet. It's common to keep callback installed while the socket is connected. Once the socket is closed, the deinitialization process starts. If the callback callee component gets deallocated before the socket object is deallocated, it should be able to cancel callbacks.

Reviewed By: yfeldblum

Differential Revision: D4897335

fbshipit-source-id: 8eee26f9ebcb78a01d55598be3aff6595a3ed852

Summary:
In a previous diff I added toInverseArpaName methods but I forgot to add the
inverse. This change adds `IPVAddressV(46)::fromInverseArpaName` static methods.
I have also implemented some suggestions that were in D4867502 but I couldn't
incorporate because the diff was landed already.

Reviewed By: yfeldblum

Differential Revision: D4885198

fbshipit-source-id: b95752aa695d6675cb293f8df2daa1787383390f

Summary:
FBString.h doesn't really use any of the facilities defined in <ios>, such as the stream manipulators. No sense dragging it into FBString.h.

This could potentially break downstream users if they are not already including the io facilities they are using. It's unlikely though because the actual stream types (std::ostream, std::istream) and stream objects (std::cout, std::cin) are defined in other headers that #include <ios>.

Reviewed By: yfeldblum, Orvid

Differential Revision: D4886133

fbshipit-source-id: 56adb93280eeeef8b09320b30fb224d4f72707bf

Summary:
What it says on the tin. Add the exception_tracer library to the folly OSS build, enabled with `--enable-exception-tracer`.
Closes https://github.com/facebook/folly/pull/580

Reviewed By: Orvid

Differential Revision: D4895533

Pulled By: yfeldblum

fbshipit-source-id: 4878826c71e7d6af17845b23abc07dc48ea1aa51

Summary:
This is the last piece needed to get Folly working on Windows without PThreads.
Updating Folly's test suite to support compiling without PThreads will come next.

Reviewed By: yfeldblum

Differential Revision: D4894048

fbshipit-source-id: 6076317e1364aef82a5d3cb306bea7c2226b3cdc

Summary: It's unused, and MSVC is warning about that fact.

Reviewed By: anirudhvr

Differential Revision: D4894403

fbshipit-source-id: 767b944eb9fa0376c795555357c09bbf9179e24f

Summary:
Several other warnings that aren't reasonable to disable globally occur in folly headers.

- Wrap the unreachable code warnings in MSVC specific disable blocks to prevent problems for users.
- Use more careful bit twiddling instead of negating unsigned types
- Enable a simpler overload for bool->float conversion than one which attempts float->bool.
- Delete one unneeded undef.

Reviewed By: yfeldblum

Differential Revision: D4891583

fbshipit-source-id: 4d2efda1fe720abcb083bf29b578c065127cda24

Summary: Rather than duplicating logic (and #ifdefs), just call the helper function instead.

Reviewed By: yfeldblum

Differential Revision: D4888362

fbshipit-source-id: f5096f6029cf05526aa74bd40235ac8014824789

Summary: It was previously returning a pointer masquerading as a `uint64_t`.

Reviewed By: yfeldblum

Differential Revision: D4888325

fbshipit-source-id: 6cf6ed09f0e7a39a8a2f93d3fa14b06913c27805

Summary:
Folly is gaining support for compiling without PThread support on Windows, but we need a way to know that at compile-time for certain APIs.
This also includes changes to guard the only API outside of portability/PThread.h that needs to be guarded on the existence of PThread.

Reviewed By: yfeldblum

Differential Revision: D4889526

fbshipit-source-id: 21175ad90f60a47718c7e2775e3b429b2aad62e2