Summary:
[Folly] `constexpr_abs`.

Is `constexpr`.

Works over integral and floating types.

If given an integral type, the return type is the usigned version of that integral type, thereby avoiding the undefined behavior of `std::abs(std::numeric_limits<int>::min())`.

Reviewed By: simpkins

Differential Revision: D3654072

fbshipit-source-id: 24fefc0c3b055f78ba3e07472c38fb9c550e0f31

Removing noexcept specifications in constructors for Synchronized that call contextualLock() and contextualRLock()

Summary:
Most mutex lock() functions do not have a noexcept guarantee, saying that the
constructor for Synchronized based on whether the underlying constructor for
the type stored is not enough.  Although this will *rarely* cause bugs, it
probably can be fixed

Reviewed By: simpkins

Differential Revision: D3682974

fbshipit-source-id: ec0bb701d0af41ffc79128fe8db7935a5f19bc70

Summary:
We are definitely not prepared to handle
SIGPIPEs, so add MSG_NOSIGNAL to sendmsg
of AsyncSSLSocket.

This is a problem which exists in openssl
as well which calls send with flags = 0.
We recently made a change to move the send
into our control, so we can now supply the
flag

Reviewed By: yfeldblum

Differential Revision: D3686679

fbshipit-source-id: ff8fe662e62923c25876bdfd516352639505dca6

Summary:
Update the documentation for Synchronized to remove references to the
various SYNCHRONIZED macros, and document the lock() and withLock() APIs
instead.

Reviewed By: yfeldblum

Differential Revision: D3618871

fbshipit-source-id: e970f9a23e45831d62232eea2ba133a55e5a4a49

Summary: It calls syscall, but does not include the header.

Reviewed By: knekritz

Differential Revision: D3586636

fbshipit-source-id: 2ef05fc4b88f236a84b79afa708e98fe21529685

Summary:
Depends on D3648195

This test example is intended to demonstrate the methodology for using DeterministicSchedule support for auxiliary data and global invariants.
The main goal is fine-grained invariant checking, ideally after every shared update.
The secondary goals are:
- Minimize intrusion in the original code. In this proposed methodology, it is adding a friend.
- Minimize duplication of original tested code. Unfortunately, depending on the original code, it seems that significant duplication may be unavoidable if we don't want to change the original code.

This diff is primarily about the methodology for testing already developed code. I plan to apply what we agree on through this diff to the dynamic MPMCQueue code (D3462592).

A future goal to keep in mind is creating a methodology for developing new code with hooks for DSched aux. data and invariant checking integrated in it, in order to minimize or eliminate duplication of tested code.  In past projects, I used non-standard source code (basically algorithm code) that is automatically translatable through scripts and macros to input to a DSched-like tool as well as to compilable code. The main challenge for such a methodology is to allow the original source code to be standard readable C++ code.

Reviewed By: djwatson

Differential Revision: D3675447

fbshipit-source-id: aae2c9f0550af88dc3a5dcbe53318a75a86b6e2b

Summary: This switches the places in Folly that need to explicitly reference the socket portability implementation to do exactly that.

Reviewed By: yfeldblum

Differential Revision: D3299984

fbshipit-source-id: 57cd8ebe66c9055aba66581a8c0fcf6c125d96f9

Summary:
Add some tests to test the other levels of the timer wheel.

They are slow by necessity.

Reviewed By: yfeldblum

Differential Revision: D3637132

fbshipit-source-id: badf8d37d726dbeb5a8220d50c60b8efdaee7989

Summary: This feature doesn't make sense when wheeltimer doesn't constantly tick - we always have to get the current clock time.  On the plus side, we'll only be grabbing the clock on timer schedule or timeout, never for individual ticks.

Reviewed By: yfeldblum

Differential Revision: D3637088

fbshipit-source-id: ed8fe52419259332a14b6dc1d357979dcf258a20

Summary: It's perfectly possible that the default crypto context simply hasn't been created yet, so try to create it if the initial acquisition fails.

Reviewed By: yfeldblum

Differential Revision: D3673138

fbshipit-source-id: 122955df04055ff4f99513b182375d4388dd0305

Summary: As-of C++11, destructors are assumed to be `noexcept` unless explicitly marked otherwise. `Watchdog`'s destructor throws, so switch it to a `LOG(FATAL)` instead.

Reviewed By: andriigrynenko

Differential Revision: D3672621

fbshipit-source-id: 5224ecf85d101462e02e12da257e033bab4db1a1

Adding policies for all the upgrade and downgrade mutex transitions that are going to be supported by Synchronized

Summary:
This diff contains the lock policies that will be used by Synchronized to
implement mutex transitions by means of heterogenous RAII mutex wrappers

Reviewed By: yfeldblum

Differential Revision: D3665020

fbshipit-source-id: a5509dfd58a1dd6cd60a7d3afe929d0da860926d

Summary:
This diff adds support for upgradable mutexes to the LockTraits
abstraction used by folly::Synchronized

Reviewed By: yfeldblum

Differential Revision: D3645453

fbshipit-source-id: 30f16eb3fbebc687a4136256f1103962c0e4c465

Summary: Because the former is standardized, and the latter is a syntax error under MSVC.

Reviewed By: yfeldblum

Differential Revision: D3672667

fbshipit-source-id: c0149b11367e36ba5574625240c41a167348199f

Summary: RequestContext update.

Reviewed By: mibpl

Differential Revision: D3604937

fbshipit-source-id: 07b315fe22a6dba40f0bab53c8092f35c172ae85

Summary: The portability implementation of `mmap` for Windows doesn't currently support anonymous shared allocations, as they are non-trivial to manage, and the places this is being used doesn't actually need the memory to be allocated as shared, so allocate it as private instead.

Reviewed By: yfeldblum

Differential Revision: D3671495

fbshipit-source-id: e74d4fd925363fef16c1bf8445da1ff32bf8266d

Summary: The tests aren't dependent on it being pthread, so use standardized stuff instead.

Reviewed By: yfeldblum

Differential Revision: D3665698

fbshipit-source-id: ad91facb75a9c5d7a90bfa294cc98bb07629de1b

Summary: Without `WIN32_LEAN_AND_MEAN` defined, including `Windows.h` includes a massive number of extra headers. There are situations that need things that are defined in those headers, so keep folly working even when it isn't defined.

Reviewed By: yfeldblum

Differential Revision: D3671350

fbshipit-source-id: 0de986e17cdd4be386be8a9eeb0075b4af44024d

Summary: To make it possible for things to actually compile, this adds `socketpair` and the `sockaddr_un` struct, and also removes the `FOLLY_HAVE_UNIX_SOCKETS` define, as it is no longer needed.

Reviewed By: yfeldblum

Differential Revision: D3671158

fbshipit-source-id: 7333470f2e85c24edb935be5e1b94b4edc6e7267

Summary: The comment tells the truth: StaticMeta doesn't mix well with MSVC's TLS implementation.

Reviewed By: yfeldblum

Differential Revision: D3671274

fbshipit-source-id: 293eb32699ad5cee59965f24f985ec7099c90136

Summary: Because the lint error was annoying me.

Reviewed By: yfeldblum

Differential Revision: D3671252

fbshipit-source-id: 2962db7616077f531e64c6f2b26ad708c7adf6ed

Summary:
This is done by using the intrinsic directly instead.
This also marks the input parameter as `volatile`, to make it more clear that that's how it is handled by `_InterlockedExchangeAdd64`.

Reviewed By: yfeldblum

Differential Revision: D3671320

fbshipit-source-id: 6010085ec3b6952a3eb1e952965ec6ad87566db2

Summary: Because it contains `wchar_t`'s on Windows.

Reviewed By: yfeldblum

Differential Revision: D3672098

fbshipit-source-id: b49db642dedf48bf7379cf339130c93f52a22f9a

Summary: Which is the case when compiling under MSVC.

Reviewed By: pixelb

Differential Revision: D3671357

fbshipit-source-id: b7e51479cae44933c3f1caa21d45775a32f294a3

Summary:
Because we're constructing the value with a placement new, which has some of C++'s most unhelpful behavior ever put into the spec: If `p` is `nullptr` and we are not compiling in C++14 mode, where the restriction was changed, then the placement new will do absolutely nothing at all. By adding the assumption that `p` is not `nullptr`, we'll trip a segfault in release mode rather than failing silently.
Note that MSVC would generate the nullptr check regardless of which mode it's in, so this assume forces the removal of the check.

Reviewed By: yfeldblum

Differential Revision: D3651116

fbshipit-source-id: ee15a38f85ce4e3cb3186fda0b7bcca39acda27a

Summary: melaniesubbiah introduced onSet / onUnset callbacks on RequestData in D3604948; we need unset() to be called when an RC is overriden with RequestContext::create() so that things work as expected. Also, change the order of calling onSet / onUnset - from RequestData perspective, it shouldn't look like there are two contexts set at the same time

Reviewed By: palmtenor

Differential Revision: D3667017

fbshipit-source-id: b9bfb858fe65ffb11de8e6d6f13b8f4cf6266bc9

Summary: There are a few places that need this, so make it so.

Reviewed By: yfeldblum

Differential Revision: D3667234

fbshipit-source-id: 84c16e1b036d9c2afddf03aa84c43210c5672f0a

Summary: Well, make it compile anyways. There's no simple equivelant for Windows, so just return 0 instead.

Reviewed By: yfeldblum

Differential Revision: D3667474

fbshipit-source-id: 02224c6666dfcfdec237bfbbd4714170407a952a

Summary: Because they simply didn't work before.

Reviewed By: yfeldblum

Differential Revision: D3666894

fbshipit-source-id: 7a34073b2bbc43c489ad963c28fac24dcbb187f2

Summary: `RangeEnumerator`s `begin()` and `end()` could return different values, but `Enumerator`s `operator ==` didn't support comparision with different types.

Reviewed By: yfeldblum

Differential Revision: D3662576

fbshipit-source-id: cfd10fffd220c70191ce0ac2ed78edd35daf5538

Summary: There is no reason at all for this to be a macro, so get rid of the macro.

Reviewed By: igorsugak, yfeldblum

Differential Revision: D3666339

fbshipit-source-id: cf131fd4182fe89c5ce0c981edf9bd7fb46158a9

Summary:
Because, if you aren't compiling with `WIN32_LEAN_AND_MEAN`, including `WinSock2.h` will result in `small` being `#define`'d as `char`. The best way to work around the issue is to simply change the name of the member to something else.
It would also have been possible to solve the problem by adding a section to `folly/portability/Windows.h`, but that would have required including that header in `folly/Function.h`, which there really is no reason to do.

Reviewed By: yfeldblum

Differential Revision: D3666417

fbshipit-source-id: 21c0363a4b77bb01e4ec20b2fc625c40729879c3

Summary: The mode parameter to `open` under MSVC is not the same as the mode parameter everywhere else, so we need to do a bit of translation.

Reviewed By: yfeldblum

Differential Revision: D3651218

fbshipit-source-id: 80df1e15f34b8d66533256107d8c9218f757fde2

Summary: This code was relying on the `- 1` overflowing as a 64-bit value, but MSVC (correctly in my opinion) was overflowing this as a 32-bit value, resulting in a segfault when trying to run the bitvector and eliasfano tests on MSVC.

Reviewed By: yfeldblum

Differential Revision: D3652343

fbshipit-source-id: 38a22abfc0d05ab2f070c450eebfa69af07d26af

Summary: We need to make sure RequestContext is unset properly for correct attribution of events to requests in BPF. djwatson, is there a reason not to set RequestContext when running runLoopCallbacks() from EventBase destructor?

Reviewed By: yfeldblum

Differential Revision: D3640289

fbshipit-source-id: bc48e936618adb1a1619de004b8479f58d3b683d

Summary: Closes https://github.com/facebook/folly/pull/429

Reviewed By: mzlee

Differential Revision: D3649806

Pulled By: Orvid

fbshipit-source-id: 77288e0a1aedf15a18f558e18fbc1dc3a56e5fd6

Summary:
Because I fail at typing underscores apparently.
This also switches the shifts over to using `kLockBitMask_` instead, which was already defined for us.

Reviewed By: yfeldblum

Differential Revision: D3652483

fbshipit-source-id: 6bd527beeb90bea8ee7632c0a3bfbbb9e0a7e2e7

Summary:
Fixes make check problem for MallctlHelperTest.

Previous make check output:

MallctlHelperTest.o: In function `MallctlHelperTest_valid_read_Test::TestBody()':
MallctlHelperTest.cpp:(.text+0x25): undefined reference to `testing::internal::AlwaysTrue()'
MallctlHelperTest.cpp:(.text+0x2e): undefined reference to `testing::internal::AlwaysTrue()'
MallctlHelperTest.cpp:(.text+0x51): undefined reference to `testing::Message::Message()'
MallctlHelperTest.cpp:(.text+0x72): undefined reference to `testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)'
MallctlHelperTest.cpp:(.text+0x85): undefined reference to `testing::internal::AssertHelper::operator=(testing::Message const&) const'
MallctlHelperTest.cpp:(.text+0x91): undefined reference to `testing::internal::AssertHelper::~AssertHelper()'
MallctlHelperTest.cpp:(.text+0xe4): undefined reference to `testing::Message::Message()'
MallctlHelperTest.cpp:(.text+0x111): undefined reference to `testing::inte
Closes https://github.com/facebook/folly/pull/448

Reviewed By: yfeldblum

Differential Revision: D3659427

Pulled By: Orvid

fbshipit-source-id: c1445b881bbebdace4defc02024a5184fd821ed6

Summary: folly AsyncPipeReader takes a callback of type AsyncReader::ReadCallback. Now AsyncReader::ReadCallback class supports IOBuf as a buffer for transfer read bytes. Need to extend AsyncPipeReader class to support IOBuf as well

Reviewed By: yfeldblum

Differential Revision: D3650893

fbshipit-source-id: e2142341c8b8b0b2ef248c1f13a8caba9d50ba67

Summary:
Depends on D3648146

Atomic counter test with:
- Buggy path triggered by an env var
- Auxiliary data
- A global invariant
- A function to be called with shared accesses to update auxiliary data and check the global invariant.

Reviewed By: djwatson

Differential Revision: D3648195

fbshipit-source-id: 18620a887f114abf31ba1261c38287139a1591a7