Summary:
I accidentally forgot to specify the capacity for my
MPMCQueue.  When I then did a blockingRead(), I got a SIGFPE.  Thanks
to a custom signal handler that doesn't print stack traces, and a few
more comedy of errors, I lost a day to this.  With this patch, I would
have gotten an assertion failure instead.

Reviewed By: yfeldblum

Differential Revision: D4169033

fbshipit-source-id: fab97ea0d5afc3c06885758b31a5e8c91ae75a45

Summary: We currently store the previous value on creation of RequestContextScopeGuard and reset it to the previous one when it goes out of scope - this means that if it's not unset properly somewhere, we'll prolong its life by saving it and restoring later. We need to do this because of some edge cases but a RequestContext should generally never be overridden by a different RequestContext - let's add a warning if this happens

Reviewed By: djwatson, palmtenor

Differential Revision: D3971904

fbshipit-source-id: e72b5f01102d18977d8aa5f8dca5a7802545098a

Reviewed By: yfeldblum

Differential Revision: D4162763

fbshipit-source-id: 25c9bfae2e7679f4b98a3d64ee9f2319eb6e7f4a

Summary:
[Folly] Let `folly::range(const std::array<...>&)` be `constexpr`.

This may be useful for future work.

Reviewed By: simpkins

Differential Revision: D4165608

fbshipit-source-id: 8f1064c3cdc07301e198acd596ff26724d603cdd

Summary:
Fix these macros not to self-shadow for nested uses.
How? Make each local variable name include __LINE__.
This works in most cases, but not all: if you put the
nested uses all on one line, you'll still get shadowing warnings.

Reviewed By: yfeldblum

Differential Revision: D4161553

fbshipit-source-id: 9e11ae6778272c733a4c820cfb30c5db59998a5b

Summary:
Because the intrinsic version requires explicitly adding `__target__` attributes, which results in things not being inlined. Although the code generated with the `__target__` attribute is strictly better, ensuring it's applied on all the relevant functions is error-prone, so just use the inline assembly version for GCC/Clang so that it can be inlined elsewhere. MSVC will inline the intrinsic version without any issue.
This also marks the functions as `ALWAYS_INLINE`, as the diff that is getting reverted made that change as well.

Reviewed By: yfeldblum, philippv, ot

Differential Revision: D3963935

fbshipit-source-id: 47175d64e7be351eb455a4d053b91ce9392bf152

Summary:
Some include files are not installed, causing including symbolizer/Symbolizer.h to fail.
Closes https://github.com/facebook/folly/pull/512

Reviewed By: philippv

Differential Revision: D4161113

Pulled By: luciang

fbshipit-source-id: 5a5f8577f8d84ba33f89073781d374b99ba37df6

Summary:
Because, unfortunately, it isn't exported from the dynamic CRT dlls :(
There's not really a nice way to handle this when using the dynamic CRT without doing very fragile hocus-pocus that relies on the exact layout and implementation details of the file descriptor table in the CRT, so the best we can really do is close the socket and just let the file descriptor itself leak.

Reviewed By: yfeldblum

Differential Revision: D4156558

fbshipit-source-id: 32cb4bf357f6746cf6597b66649ff9f018fb1bed

Summary:
Create a local std::ios_base::Init instance to ensure that it is valid, then
use std::cerr.

Reviewed By: yfeldblum, nbronson

Differential Revision: D4139681

fbshipit-source-id: 03377dd417710e320a6b53298d507fd0168592f6

Reviewed By: yfeldblum, nbronson

Differential Revision: D4149681

fbshipit-source-id: 37bd1b0b7d1ad6e6fa813228307abebfe772012f

Summary: Because GTest doesn't support it on platforms that don't implement `sigaction`.

Reviewed By: yfeldblum

Differential Revision: D4155882

fbshipit-source-id: fe8df316242b293afaf94c2a5d0f8a5e60b51285

Summary: As the comment says, this disables a couple of warnings related to exporting classes derived from stdlib classes that aren't explicitly exported.

Reviewed By: yfeldblum

Differential Revision: D4155978

fbshipit-source-id: 6e732b53c280a3bc3a39b2128cd577ba7cb70408

Summary: Because MSVC generates warnings if you have a control-flow statement followed by a single trailing semicolon.

Reviewed By: yfeldblum

Differential Revision: D4155588

fbshipit-source-id: dfd8774fc6a62675764f7e069c26b799b622a9af

Summary: Without this flag, we were unintentionally requesting a context with access to private keys.

Reviewed By: yfeldblum

Differential Revision: D4155525

fbshipit-source-id: f33d18451b06e32b81d03bf6180efc1671cfa204

Summary: Because `CHECK_EQ` is a fatal error, and makes it impossible to keep running the other tests if it fails, even if it was just a timeout.

Reviewed By: yfeldblum

Differential Revision: D4151084

fbshipit-source-id: db88dc2ef875e5d1fe31792f26a3dc2d223ded5e

Summary: So that they can be run independently of the tests.

Reviewed By: yfeldblum

Differential Revision: D4150331

fbshipit-source-id: 3ab39024795add84885436b757f2505527297a3d

Summary: When the implementation of `clock_gettime` for `REALTIME` and `MONOTONIC` was switched to use `std::chrono`, this didn't get switched over to the resolution of the new implementation.

Reviewed By: yfeldblum

Differential Revision: D4150297

fbshipit-source-id: a4578af85cae538a3ebb6da7e759058927c31d3e

Summary: Expose isFamilyInet() in SocketAddress. This cleans up code and provides a way to validate if SocketAddress is a ipv4 or ipv6

Differential Revision: D4150650

fbshipit-source-id: dc8883e904b6577fc27bdd54064fcc50de93b0d2

Summary:
The min value of a `char` is `-128`, but we're initializing our `size_t` i's with it, so, as MSVC quite rightly warns (as C6294) the condition is never true and the loop never loops.
Fix it by signing our i's.

Reviewed By: yfeldblum

Differential Revision: D4145419

fbshipit-source-id: 87591d0f84c54472b1b5847e025d091de3f98bca

Summary:
this diff adds tryReadUntil, which is a mirror of tryWriteUntil in both function and implementation.
Two bugs were exposed in the process of implementing and testing tryWriteUntil; they are fixed as well and are as follows:
  1. tryObtainPromisedPopTicket didn't assign to the passed ticket return reference in the failure case
  2. TurnSequencer::tryWaitForTurn() didn't distinguish between past turns and timeouts in the failure case; they need to be
     differentiated because SingleElementQueue::tryWaitFor{De/En}queue() should only fail in the timeout case, not if the turn has passed.

The two added unit tests are admittedly clumsy, but making the obvious simplifications to them keeps them from triggering the premature timeout race caused by bug 2 above, so I kept them as is.

Reviewed By: magedm

Differential Revision: D4050515

fbshipit-source-id: b0a3dd894d502c44be62d362ea347a1837df4c2f

Summary:
These functions contain static locals which need to be exported to
the global dynamic symbol table to get deduplicated at runtime.  Since
using `-fvisibility-inlines-hidden` demotes the visibility of these
static locals, explicitly tag them.

Reviewed By: yfeldblum

Differential Revision: D4139154

fbshipit-source-id: 08b81721c6c945ac5556472481ae771d0eeb5f88

Summary:
`prepareReadBuffer` is calling a callback function that is not a noexcept
also `prepareReadBuffer` is being called only from one place, that wraps this function call with try/catch.

Reviewed By: jmswen

Differential Revision: D4138424

fbshipit-source-id: a05bdd6f741761567a7d0291017c285b0bf15522

Summary:
This tags certain static locals, wich may get duplicated via dynamic
linking and inlining, as safe to have multiple copies at runtime,
making this subtle behavior explicit.

Reviewed By: igorsugak

Differential Revision: D4082929

fbshipit-source-id: ba4e23cb121e957a43f5659a1ca3432cb89cb8f3

Summary:
[Folly] Let `folly::range` be `constexpr`.

It will be useful to have this helper function be `constexpr` to support further compile-time code.

Reviewed By: juchem

Differential Revision: D4135943

fbshipit-source-id: a62be93f9e492ca302130d1a3b190ed4b69f7a80

Summary: add operator== against nullptr_t for ReadMostlySharedPtr

Reviewed By: andriigrynenko, nbronson, yfeldblum

Differential Revision: D4128722

fbshipit-source-id: 40d08bb85bfe2f96ad4ed4995f5829e0616d0661

Summary: Eden uses this and won't build with OSS folly without it.

Reviewed By: Orvid

Differential Revision: D4132103

fbshipit-source-id: 68d6c7dc642a7401eca60b0713db9f90cc11ced1

Summary: Changed RWSpinLock to a SharedMutex in the RequestContext to see if this would lower the overhead of the onSet/onUnset callbacks.

Reviewed By: djwatson

Differential Revision: D3780396

fbshipit-source-id: 3d91f8194357533072fe053d23e0454a36faecff

Summary: This allows getting up to n bytes from the queue without first having to check the length.

Reviewed By: yfeldblum

Differential Revision: D4083484

fbshipit-source-id: 2a468992c97f036c22f1a0d9f830e6d5286a4bc2

Summary: This is helpful for parsing data IOBufs in reverse.

Reviewed By: siyengar

Differential Revision: D4082810

fbshipit-source-id: 6a201d25e7d22befe28f92e4a1d7aa41ad7d6817

Summary: gcc-4.9 doesn't appreciate this clever loop and worries about `prev` being uninitialized on first use. Assuming the rest of the program behaves properly and preserves the invariant this code is expecting, this isn't bugged. But let's initialize it anyway.

Reviewed By: meyering

Differential Revision: D4120746

fbshipit-source-id: 1a7c323a4b6296a81768a62dd7d72337c5c35bf0

Reviewed By: yfeldblum

Differential Revision: D4120553

fbshipit-source-id: 87c202232bcfabeff7eb62a8133b9b5577b09cbc

Summary:
There was a doubly-nested loop, both with index "i".
Change the inner for-loop index from i to j.

Reviewed By: yfeldblum

Differential Revision: D4120589

fbshipit-source-id: c786d8f7bb1ee05fc990db898b15836032e93940

Reviewed By: jsedgwick

Differential Revision: D4120563

fbshipit-source-id: c97645a068662e41d5038bcd1e9805bdf6f0490c

Summary: Allow getting the sequence number of a token via a read only getter function

Reviewed By: yfeldblum

Differential Revision: D4120900

fbshipit-source-id: b664dda29d13a1755e041ab9c33c0d7324690ba7

Reviewed By: yfeldblum

Differential Revision: D4086486

fbshipit-source-id: bd0cca8dd2c9b74d5c30e4cd095191c1d1ecab79

Summary:
Solves #509 by creating a libtool convenience library that's compiled with -msse4.2.
Closes https://github.com/facebook/folly/pull/510

Differential Revision: D4120400

Pulled By: yfeldblum

fbshipit-source-id: bf5d937dc37ef8707e755c89f1883d65b4d21b0f

Summary:
We would like to guarantee that after `folly::ThreadLocal<>` dtor
returns no per-thread instances are longer alive.  Currently this is not a case:

* T1 is excuting `StaticMetaBase::onThreadExit()`, it acquired all per-thread
  instances and erased them from meta under `accessAllThreadsLock_`.
* T2 destroys `folly::ThreadLocal<>`, it executes `StaticMetaBase::destroy()`,
  collects all per-thread instances (thus missing the ones being destroyed by
  T1), destroys them and returns.
* T1 executes dtor of per-thread instances, after parent `folly::ThreadLocal<>`
  dtor is finished.

Reviewed By: ot

Differential Revision: D4109820

fbshipit-source-id: d547b8cc77c9871126538c38644c2e98ddccf220

Summary:
Make sequence number in AtomicBatchDispatcher<....>::Token non-const:
- The field is already private and having it as const prevents a
  move assignment operator from getting defined

Reviewed By: yfeldblum

Differential Revision: D4114851

fbshipit-source-id: 9f7a4003daff02c007c01747cca6ae9da17fcb79

Summary:
MSVC doesn't allow uninitialized non-`extern` `const` declarations, but we can't mark them `extern` because they are part of a template specialization. We also can't initialize them, because they'd conflict with the definition specializations in the generated tables.
As the forward-declarations aren't required for it to work under MSVC, as the specializations are found appropriately, just don't declare the specializations under MSVC.

Reviewed By: yfeldblum

Differential Revision: D4098282

fbshipit-source-id: 84b73d63bbe6cf9c54b7fe7a3bfc2488699df7c2

Summary:
In the next revision of clang, compilation generates multiple erroes of the form

   folly/TokenBucket.h:127:29: error: exception specification is not available until end of  class definition
         double nowInSeconds = defaultClockNow()) {

which are eliminated by reordering the method declaration for defaultClockNow()

Refer https://llvm.org/bugs/show_bug.cgi?id=30860

Reviewed By: philippu, yfeldblum

Differential Revision: D4107443

fbshipit-source-id: ce64f2ae7983e533c2fcb5cb043dbdd3da5c00f7