Summary:
Changed DSched interface for managing auxiliary functions to allow separate auxiliary functions for single actions (applicable to the next shared access by a specific thread) and repeating actions (applicable to all subsequent shared accesses).

[Note: I have a dependent diff that depends on both this diff and the diff for dynamic MPMCQueue (/D3462592). I don't think I can submit a diff that depends on multiple diffs that haven't landed yet. So, I'll wait until this one lands.]

Reviewed By: djwatson

Differential Revision: D3792669

fbshipit-source-id: 52654fffda2dc905b19ff91f4459f15da11f7735

Summary:
The previous version assumed that `RegionSize` would always be the full size of the allocation done by `VirtualAlloc`. However, `RegionSize` actually only includes the following pages that have the same attributes, so, if you change the access permissions via `mprotect`, the `RegionSize` would exclude that region, which is not what was intended.
This instead stores the length and a dummy magic value after the end of the requested allocation.

Reviewed By: yfeldblum

Differential Revision: D3812949

fbshipit-source-id: 53bbbcc371accbed08adaffa82fc082ec44f316f

Summary:
We were doing an unnecessary and wasteful string conversion in the
SocketAddr codepath.  This eliminates it.  I also noticed we had an off-by-one
in the "convert string to char buffer" code path, so I added a test to confirm
the bug and fixed it.

Reviewed By: yfeldblum, meyering

Differential Revision: D3817959

fbshipit-source-id: 51fed8331ab23c0888a3d1f9e0cc9cea5ea8329b

Summary:
This gets the socket portability layer functional enough that most of the socket tests are passing, the few that are left are depending on specific error messages.
This also switches all of the additional overloads for some of the socket functions to forward to a single implementation, to make adjustments to these functions easier in the future. (most of the functions already needed adjustments and would have had to change regardless)

Reviewed By: yfeldblum

Differential Revision: D3814011

fbshipit-source-id: c6793ee74a91d9e164775a2d52c96f54b28b9f24

Summary:
This code compiles and is causing stack overflow at runtime:

```
using F = folly::Function<void()>;
void foo(F);

F bar;
auto baz = [bar = std::move(bar)] {
  foo(std::move(bar));
};
baz();
```

The bug there is that `baz` is missing `mutable` keyword, so when
constructing argument for `foo`, `F(const F&&)` is called, which is selecting
`template <typename Fun> F(Fun&&)` (where `Fun = F const`) and we end up in
an infinite `F<Fun>(Fun&&) <-> F<Fun>(Fun&&, SmallTag|HeapTag)` cycle.

This diff transforms this easy-to-make-bug into compile-time error.

Reviewed By: yfeldblum

Differential Revision: D3810269

fbshipit-source-id: f80a18ab02bd0715d692cf67c3c8943f557c2982

Summary:
itshappening

Need to override unit test failures after repeated landing failures unrelated
to the change.

Reviewed By: yfeldblum

Differential Revision: D3803301

fbshipit-source-id: b6581e3d2ff6baba57eb0f61b890a61107118bf7

Summary: Now builds correctly

Reviewed By: meyering

Differential Revision: D3763879

fbshipit-source-id: e272fbcc28a74fcf36b63a0135534c5063a7c4ee

Summary: Fix code that is transitively including ScopeGuard.h via FBString.h.

Reviewed By: yfeldblum

Differential Revision: D3801328

fbshipit-source-id: 7e1dc37cd6dd3aa691dd1baf31385d3a8c51eed0

Summary: Make sure exception is propagated to caller (especially when Observer is just created).

Reviewed By: yfeldblum

Differential Revision: D3798991

fbshipit-source-id: cee8452cfd40dcfbaf0e2ae2c2ee628af0362c6e

Summary:
Minor changes. Simplified the memory-handling explanation; also fixed some grammar issues and re-worded some confusing paragraphs. (I suggest reading the edited and unedited versions separately.)
Closes https://github.com/facebook/folly/pull/459

Reviewed By: simpkins

Differential Revision: D3779296

Pulled By: Orvid

fbshipit-source-id: 24b086cbd0b67e4c592731aeec6a7ffc14ff0319

Summary:
Update TimeseriesHistogram::rate(int level) to have a configurable return type,
similar to the rate(TimeType start, TimeType end) function, as well as the
avg() functions.  I believe it was simply an oversight initially that this
version of rate did not have a configurable return type.

Since rate() and avg() are template methods, their full definitions should
really be available in TimeseriesHistogram.h rather than
TimeseriesHistogram-defs.h.  This also fixes that problem.  Most of the logic
in these functions isn't actually dependent on the return type, so that was
split out into separate non-template helper functions that are still in
TimeseriesHistogram-defs.h

Reviewed By: yfeldblum

Differential Revision: D3776017

fbshipit-source-id: 7deebf5b9ea1be143b5d772a15246706cb0cae80

Summary:
Default namespace for GFlags has been changed from "google" to "gflags".

See: https://github.com/gflags/gflags/commit/d9d06b9.
Closes https://github.com/facebook/folly/pull/466

Reviewed By: yfeldblum

Differential Revision: D3787144

Pulled By: Orvid

fbshipit-source-id: db7bcaf4e2bcd46b022a48b17b50ef155570f296

Summary:
Move ThreadLocal object destruction to occur under the lock to avoid races.
This causes a few cascading changes - the Tag lock needs to be a recursive_mutex so
constructing a new object while destroying another st. Also, forking requires
a new mutex to avoid deadlocking on accessing a recursive_mutex across a fork()

Reviewed By: andriigrynenko

Differential Revision: D3755446

fbshipit-source-id: f1f1f92175eb39e77aaa2add6915e5c9bb68d0fb

Summary:
Currently reset does not actually reset it. This change
make sure it does the job.

Reviewed By: yfeldblum

Differential Revision: D3788869

fbshipit-source-id: 771a641e31bb3cf307e5bebb979b81a3d3feea55

Summary: Adding two methods to export the parameters used to generate the key material   (key_block). These parameter can be used to decrypt a TLS session from a packet capture.

Reviewed By: anirudhvr

Differential Revision: D3687099

fbshipit-source-id: 04137f34dd32c387a1b7aec04b3ed6066f123a8e

Summary: This should not affect correctness, but it means SharedMutex would need to share the variable across threads.

Reviewed By: yfeldblum

Differential Revision: D3621227

fbshipit-source-id: dc1baa7c47cd2d459cd0ef89451bcd7fd4d553aa

Summary:
10e9cd3e set up SCOPE_EXIT to join threads (wait for them to exit) on
exceptions. However, it is also called on normal exit. Remove the
original code at the end for joining threads.

This fixes EventBaseTest regression.
Closes https://github.com/facebook/folly/pull/468

Reviewed By: yfeldblum

Differential Revision: D3792977

Pulled By: Orvid

fbshipit-source-id: e4b12202ae3e35fd942ad2ca1d8d405cf1a28f68

Summary: Closes https://github.com/facebook/folly/pull/467

Reviewed By: yfeldblum

Differential Revision: D3787151

Pulled By: Orvid

fbshipit-source-id: e255c9daea9917082f684e52e27984770c9f08b1

Summary: Closes https://github.com/facebook/folly/pull/465

Reviewed By: yfeldblum

Differential Revision: D3787146

Pulled By: Orvid

fbshipit-source-id: 17433a256338bd107eec41e69af3eef58de3339b

Summary:
For some systems like my Fedora 23 is missing -lcrypto library to be together with -lssl

The following error ocurr running 'make check':
avoid undefined reference to symbol 'EVP_DigestInit_ex
Closes https://github.com/facebook/folly/pull/428

Reviewed By: yfeldblum

Differential Revision: D3787160

Pulled By: Orvid

fbshipit-source-id: 8ff69d00c9c752d0a005d2a5e8d68e65347cc43b

Summary:
Optional::value() returns a temporary object when the object is an rvalue. This is different in semantics then what boost::optional/std::optional do.

The decision to make the copy or not should be up to the user and not the library. Consider an example:

```
void F(Optional<T> &&opt) {
  T&& t = std::move(opt).get();
  // I know `opt` is alive in this scope, I should be able to keep a rvalue ref to the internals
}
// if we were to return a `T`, that would actually return a new temporary.
```

```
void G(T&& t);
G(std::move(opt).get()); // This could have surprising behavior too !
```

This change modified the return type to be `T&&` and also introduces an extra overload for `const T&&`. Also, deleted two test-cases that assume the lifetime to be extended. This is a breaking change but this brings folly::Optional on parity with other siblings.
Closes https://github.com/facebook/folly/pull/353

Reviewed By: ddrcoder

Differential Revision: D3714962

Pulled By: yfeldblum

fbshipit-source-id: 1794d51590062db4ad02fc8688cb28a06712c076

Summary:
Move ThreadLocal object destruction to occur under the lock to avoid races.
This causes a few cascading changes - the Tag lock needs to be a recursive_mutex so
constructing a new object while destroying another st. Also, forking requires
a new mutex to avoid deadlocking on accessing a recursive_mutex across a fork()

Reviewed By: andriigrynenko

Differential Revision: D3755446

fbshipit-source-id: bb4c4f29bab98d763490df29b460066f124303e0

Reviewed By: mzlee

Differential Revision: D3780312

fbshipit-source-id: c42c8f0a06b82520ee1b46f105a2a85ad524c442

Summary:
[Folly] `gen::dereference` should perfectly-forward unwrapped values.

The problem comes in when the wrapped value is not actually a pointer, but is actually an rvalue-ref to some other kind of wrapper type with `Inner&& operator*() &&`. In such cases, the compiler emits a type mismatch error that it cannot cast `Inner` to `Inner&&`, with the errors originating in `Dereference::foreach` and `Dereference::apply`.

Fixes a couple other missing-forwarding and extra-forwarding bugs.

Reviewed By: ddrcoder

Differential Revision: D3776617

fbshipit-source-id: 6926fc18244a572846b22d428bd407d37fb20aa1

Summary:
[Folly] Use `Synchronized` in `RequestContext`.

Because we can. And it makes the code a tad simpler and also enforces access correctness a tad.

Also use `folly::make_unique` in `RequestContextTest` to keep balance between the explicit `new` and `delete` ops.

Reviewed By: markisaa

Differential Revision: D3781115

fbshipit-source-id: 63b41ddd8009e9546e3be5f89bdd23a4d791105c

Summary:
Iterators must be default constructible.
folly::IOBuf can now be used as a range in ranges-v3.

Reviewed By: yfeldblum

Differential Revision: D3782536

fbshipit-source-id: 854813b4e3336aba50048649e6ae7b375d49e382

Summary: Title.

Reviewed By: andreazevedo

Differential Revision: D3785212

fbshipit-source-id: c551e0367196cbc68cf39a5d40f2b324883fcdf4

Summary: Added support for user-defined clock classes, improved comments, and removed part of the std::atomics use that had no effect on thread-safety.

Reviewed By: yfeldblum

Differential Revision: D3708378

fbshipit-source-id: 1a933c3707c12311584a3b33afd773ee91577167

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