Summary: Adds a standard semaphore type with signal and wait methods that is safe to use in both multi-threaded contexts and from fibers.

Reviewed By: andriigrynenko

Differential Revision: D3778943

fbshipit-source-id: 6997f1fb870739e07f982399dbebfd8b3e45daa2

Summary: Because MSVC doesn't have `random()` and `M_PI` is guarded by a pre-processor macro.

Reviewed By: yfeldblum

Differential Revision: D3767159

fbshipit-source-id: fcb1c41cd75925455c76efad38423cd52bd98aeb

Summary:
The resultant future of collectOne will be fulfilled when the first one of
the future in the list completes without exception. If all input futures throws
exception, the resultant future will get the last exception that was thrown.

Reviewed By: andriigrynenko

Differential Revision: D3764760

fbshipit-source-id: 76484254e35182eddc8266865853d65c28170f82

Summary:
This class allows easy insertion of padding bytes after an object to ensure
that two cacheline-padded elements of an array don't engage in false sharing.

Reviewed By: yfeldblum

Differential Revision: D3485144

fbshipit-source-id: a3ece1e34566b20f94ff9f66532b2386ab19a9b1

Summary:
Malloc.h is intentionally included multiple times, once from folly and once from libstdc++. The current ###pragma once## implicitly allows this to happen. FBString.h has an undef for Malloc.h's include guard, which originally accomplished this goal.

The undefing code is presently moot, since its functionality has been replaced by ###pragma once##. Remove it.

I noticed this when ott was copying FBString over to libstdc++ in D3757853.
The diff that switched the include guards to pragmas was a codemod, and was not specific to fbstring. D3054492

Reviewed By: ot

Differential Revision: D3758119

fbshipit-source-id: e796d039a031d5f842ed39bf55a6b1aeb2686bc4

Summary: Because MSVC is not happy about the member hook when used in complex inheritence scenarios.

Reviewed By: yfeldblum

Differential Revision: D3774513

fbshipit-source-id: 9e1ef8dd76d966de339f8486ff1a1d0ab1571849

Summary: Because MSVC is right, this shouldn't be happening, but we test weird things.

Reviewed By: yfeldblum

Differential Revision: D3773486

fbshipit-source-id: 50f28bf0ac8ff53f63231b4f6f9ce050b509b464

Summary:
With how this was written it would fail if the call to `lseek` failed, or if it succeeded, unless it was setting the length to 0, in which case it would succeed.
This makes it work right.

Reviewed By: yfeldblum

Differential Revision: D3773311

fbshipit-source-id: 3dc94502d0c4259f6f2766b4c0903c081d7c36ab

Summary:
Because apparently this is valid (and we test it).
This also adds a check in mmap to make sure we aren't passing an invalid handle to `MapViewOfFileEx`.

Reviewed By: yfeldblum

Differential Revision: D3772853

fbshipit-source-id: 11593997a3fb12b7b391c5e52661060b71341aef

Reviewed By: yfeldblum

Differential Revision: D3765642

fbshipit-source-id: 9b1cc4007c553da5082799fa4ed0af8f7850ec8d

Summary:
We are formatting an integer value, so it is doing absolutely nothing at all, as confirmed by the version I implemented for MSVC, which does output the value with digit separators, which fails the unit tests because the unit test expects the digit separators to not be present. What's more, whe specifically assert that the user has not requested digit separators in the format string.
This also kills the MSVC special case entirely because it's not needed.

Reviewed By: yfeldblum

Differential Revision: D3768405

fbshipit-source-id: 388cd0ca9699e257c71798b9bf355aa651748e60

Summary:
First, folly::static_function_deleter::operator() is in fact a const
operation, so this should be a reasonable change. The motivation for this is
to make folly::ThreadLocalPtr and folly::static_function_deleter play nice with
each other.

Minimal example:
```lang=c++

void deleter(int* ptr) {
  free(ptr);
}

int main(int argc, char* argv[]) {
  folly::ThreadLocalPtr<int> tl;
  tl.reset(std::unique_ptr<int, folly::static_function_deleter<int, deleter>>(
      new int(0)));
  return 0;
}
```

Currently produces:
```
folly/ThreadLocal.h:207:7: error: no matching function for call to object of type 'const folly::static_function_deleter<int, &deleter>'
      delegate(ptr);
      ^~~~~~~~
Test.cpp:10:6: note: in instantiation of function template specialization 'folly::ThreadLocalPtr<int, void>::reset<int, folly::static_function_deleter<int, &deleter>, void>' requested here
  tl.reset(std::unique_ptr<int, folly::static_function_deleter<int, deleter>>(new int(0)));
     ^
folly/Memory.h:91:8: note: candidate function not viable: 'this' argument has type 'const folly::static_function_deleter<int, &deleter>', but method is not marked const
  void operator()(T* t) { f(t); }
       ^
1 error generated.
```

With the fix, the build succeeds.

Reviewed By: yfeldblum

Differential Revision: D3764624

fbshipit-source-id: c28c791b79f1415704c205c36bfda2d888d6c010

Summary: Closes https://github.com/facebook/folly/pull/458

Reviewed By: yfeldblum

Differential Revision: D3765911

Pulled By: Orvid

fbshipit-source-id: 30de0b99ec622471e52a775835b5a0564437febc

Summary: Because it isn't. Not on MSVC anyways.

Reviewed By: yfeldblum

Differential Revision: D3767326

fbshipit-source-id: 0f9421773819999f99be38ae0646ae3e81bde4e4

Summary:
[Thrift] Use `cbegin` and `cend` in static reflection container traits.

These are functions that all the C++ standard library containers have.

And add the two methods to `folly::sorted_vector_set` and `folly::sorted_vector_map`.

Reviewed By: juchem

Differential Revision: D3763187

fbshipit-source-id: 9d467a1cf391206eba671f454da428323c4a566a

Summary:
Because event file descriptors don't exist on Windows.
This also disables the fork() test on Windows, as we don't have fork().

Reviewed By: yfeldblum

Differential Revision: D3766266

fbshipit-source-id: af8d81615957a3d7bdfcb204afbf648723921f76

Summary:
GCC 5.3 is confused that we might be trying to assign a 64
bit value to a 32 bit size_t although we are clearly not.  Just
typecast the confusion away.

Reviewed By: yfeldblum

Differential Revision: D3762839

fbshipit-source-id: 1b705c4e70b782fdb106844fee52ab25aa038acd

Summary:
1. This implements a GraphCycleDetector which can check if newly added edge belongs to a cycle in a directed graph. GraphCycleDetector is used to detect cycles between Observers when creator function is run.
2. This also fixes a bug where new dependencies could be saved even if Observer creator failed.

Reviewed By: yfeldblum

Differential Revision: D3746743

fbshipit-source-id: 99d10446c56fa4d8f7485f38309e8a282cd21bdf

Summary:
Titled.
```
mcrouter/lib/carbon/CarbonProtocolReader.h:143:49:   required from here
folly/small_vector.h:441:38: error: enumeral and non-enumeral type in conditional expression [-Werror]
cc1plus: all warnings being treated as errors
```

Reviewed By: yfeldblum

Differential Revision: D3763073

fbshipit-source-id: da490e91cdb12dacf37d71c1796239bdc361a31b

Summary:
The GCC warning "warning: enumeral and non-enumeral type in conditional expression"
is logged a lot in many builds since lots of code depends on small_vector.  This diff
should prevent those warnings.

Reviewed By: yfeldblum

Differential Revision: D3762835

fbshipit-source-id: 49831e4364e716592287c05d1dbf1912326324f6

Summary:
I tested it doesn't break the gcc 4.9 and clang builds - I didn't try any other versions of anything.

build[all]

Reviewed By: meyering

Differential Revision: D3757152

fbshipit-source-id: a126cd31cb89057dececfed1b265f452ee29fbff

Summary:
While adding logging around our socket and looking into `AsyncSSLSocket` it seems like the data that is actually written into the socket is not correctly attributed.  I
added logs and printed out what happens on the socket layer, P56563098 in this paste you can see that the `[fishhook]` logs are actually those added in D3698728.

Those are the actual bytes written onto the socket, in the paste, the bytes that are written by the AsyncSocket::bioWrite method are
the ones that actually get written onto the socket. some of the bytes written into the bio comes from bf_buff.c and bss_mem.c which are not eventually attributed to a
socket message and will be incorrectly counted when getRawBytesWritten/Read invoked on AsyncSSLSocket.cpp

Unfortunately/Fortunately this issue is not symmetrical and does not manifest in the getRawBytesReceived in AsyncSSLSocket, reading the bio for read bytes
correctly attributes the actual number of bytes written on the socket. moreover, pulling the asyncsocket data for getRawBytesRead doesnt give the full read bytes on
wire because SSL_connect and SSL_read dont return the number of bytes they read but return the number of bytes without the TLS bytes used.

siyengar seems like a right person to look at this. so adding him here.

Would love to discuss more about this and am open to iterating more on this solution

Reviewed By: knekritz

Differential Revision: D3698744

fbshipit-source-id: 541aa478778b9607f51db194fcbfe28bd23c737f

Summary:
include linux/membarrier.h if it is available.
Closes https://github.com/facebook/folly/pull/455

Reviewed By: lukenels

Differential Revision: D3714952

Pulled By: Orvid

fbshipit-source-id: 8c85756af2cb132152b2182816becfea138f0149

Summary:
`fbstring::assign()` uses `append()`, which triggers exponential growth, but it's preferable that `assign()` behaves like the `fbstring(const char*, size_t)` constructor, which is tight.

Also rewrite `operator=()` in terms of `assign()`, to avoid duplicating the logic, and refactor the logic of `append()` for the aliasing case so that it uses the same expansion operation as the non-aliasing case.

Reviewed By: luciang

Differential Revision: D3754932

fbshipit-source-id: 5423f2a360b4268b6a05dd0ae9d2fe5bd1eb855d

Summary: D3743475 adds to `Malloc.h` a dependency on another folly header, which breaks it when used in stand-alone mode. This diff moves the include to the right `#ifdef` section.

Reviewed By: Gownta

Differential Revision: D3757819

fbshipit-source-id: 71664ca6a3a47b6e4449a4ef603fedf052c5df3b

Summary: I missed this reference when I moved it to the portability folder. It is already being compiled at its new location.

Reviewed By: yfeldblum

Differential Revision: D3754227

fbshipit-source-id: 357b0c26ddbcefdc7640f6a334150abba90ed711

Summary: MSVC can't handle the array as a constexpr value, but works fine with the char*.

Reviewed By: yfeldblum

Differential Revision: D3705189

fbshipit-source-id: e8208b3f2831a720095641f0e1e72ac63ed845a0

Summary: `std::__throw_bad_alloc()` is defined in `<new>` on OSX, so bring back the `#ifdef` guards that were there previously.

Reviewed By: markw65

Differential Revision: D3749714

fbshipit-source-id: 0338a4cece928fce0b9d33d41c17cfa99a319abe

Summary:
fix(FBString): compile error on instantiate `basic_fbstring` with a `Storage` that is not `fbstring_core<E>`
Closes https://github.com/facebook/folly/pull/398

Reviewed By: ot

Differential Revision: D3714957

Pulled By: yfeldblum

fbshipit-source-id: 1c5d2538b674049f7e1872a0b623ec330dc8d7b2

Summary: It only needed a minor tweak, but the change still had to be made :(

Reviewed By: andriigrynenko

Differential Revision: D3745021

fbshipit-source-id: 286c6db706c3571842006537c6b17f506609e51d

Summary: MSVC didn't like the conversion to using `Expected`, and, after `Expected` was fixed to work under MSVC, conv still needs more changes. Specifically MSVC doesn't understand the single-instantiation form of getting the last element, so we have to switch to a tuple-backed version instead, which requires more template instantions, but produces the same performance at runtime.

Reviewed By: ericniebler

Differential Revision: D3744063

fbshipit-source-id: affcab1574c721d8b9529784d7ca2a46233d9935

Summary:
When calling folly::to<SomeString>(double), generic implementation will
firstly reserve 24 (or 25 when negative value) bytes. This will introduce
a malloc call for most of mainstream string implementation.

But for most cases, a floating point doesn't need 24 (or 25) bytes to
be converted as a string.

This diff try to introduce a special version which does not do string reserve.

Reviewed By: ericniebler

Differential Revision: D3728171

fbshipit-source-id: d70ead396ad6c8d0df1f542c5516f7534e82cb97

Summary:
[Folly] An intro to the upgrade mutex in the `Synchronized` docs.

Describes what the upgrade mutex is. Extends the existing docs which describe `Synchronized` and `LockPtr` interface and behavior in the presence of an upgrade mutex.

Reviewed By: snarkmaster, simpkins

Differential Revision: D3746177

fbshipit-source-id: 68b0570a36cc1f4393d5ccca535efa02752ca11d

Summary: Lets the kernel choose the port instead of hardcoding it.

Reviewed By: djwatson

Differential Revision: D3745911

fbshipit-source-id: d9680ec286e8015abb9274c30b572ff1d91548ce

Summary: [Folly] Remove a dead comment in `folly/test/SynchronizedTest.cpp`.

Reviewed By: simpkins

Differential Revision: D3745609

fbshipit-source-id: acdbd3eaa6d947213b72fe13cec0291545a60c87

Summary: Because it, and a whole bunch of other things, are used in the header but not properly included.

Reviewed By: yfeldblum

Differential Revision: D3744653

fbshipit-source-id: c10dbb83109200b6186b8ed5ef0d2447d4200f69

Summary: Well, the explicit instantion for it anyways. The extern template declaration for it declares it as `noexcept`, so MSVC generates an error because the explicit instantiation is not also marked as `noexcept`

Reviewed By: yfeldblum, ericniebler

Differential Revision: D3744090

fbshipit-source-id: 4e756b2761c23a436097a6131b9b2ecd59faf4f9

Summary: Because it is a portability header, but was created before portability headers were cool.

Reviewed By: mzlee

Differential Revision: D3743475

fbshipit-source-id: 5d2fe23ce08f0425ce48b4871fa660e69f57cc39

Summary:
This diff updates the documentation for folly::Synchronized to include
upgradable locking

Reviewed By: yfeldblum

Differential Revision: D3740983

fbshipit-source-id: d201fcfa6f62ce168125d2a9caa096e079446efa

Summary: Make strict mode stricter, by not allowing singleton to be fetched after shutdown (even with try_get).

Reviewed By: yfeldblum

Differential Revision: D3737925

fbshipit-source-id: 8d5536c4f27e13feee722b5abeb15db6fe3d77bf