Summary:
Update the logging library so that FB_LOG() and FB_LOGF() also accept
streaming style arguments:

  FB_LOG(logger) << "logs can be written like this now: " << 1234;
  FB_LOG(logger, "both styles can be used") << " together";
  FB_LOGF(logger, "test: {}, {}", 1234, 5678) << " and with FB_LOGF() too";

Streaming support does make the upcoming XLOG() macros more complicated to
implement, since the macro has to expand to a single ternary `?` expression.
However I was able to come up with a solution that works and has minimal
overhead.

Reviewed By: wez

Differential Revision: D5082979

fbshipit-source-id: 11734e39c02ad28aceb44bbfbd137d781caa30cf

Summary:
This begins adding a new logging library for efficient, hierarchical logging.

This includes the basic library framework, plus a README file with a brief
overview and the motivation for creating a new logging library.

Reviewed By: wez

Differential Revision: D4911867

fbshipit-source-id: 359623e11feeaa547f3ac2c369bf806ee6996554

Summary: Closes https://github.com/facebook/folly/pull/609

Differential Revision: D5228342

Pulled By: Orvid

fbshipit-source-id: edb81284a0401a4ea267310e1ca01c390bcdfb32

Summary: 2_ms seems too short. I am not sure whether it's feasible to check whether thread is waiting for an address. We could wait for longer to reduce false alarm.

Reviewed By: nbronson

Differential Revision: D5220819

fbshipit-source-id: 42f31206e9cb7f9addaa049d0e7cd995f6735f6c

Summary:
[Folly] Let `SubprocessError` inherit `std::runtime_error`.

As an added bonus, this gives it `std::runtime_error`'s refcounted string for cheap copies.

Reviewed By: ericniebler

Differential Revision: D5216758

fbshipit-source-id: 43298e06f02cfd88abf2d73f7aa16117a6cb052b

Summary: The source and tests for the stats directory was spread across folly/detail and folly/test, move them into folly/stats directly instead.

Reviewed By: yfeldblum

Differential Revision: D5216810

fbshipit-source-id: 00a8bb95a4f7830d0bc46b3f914f256a37833b78

Summary: Use clang-tidy to mechanically add missing `override` and remove redundant `virtual`.

Reviewed By: igorsugak

Differential Revision: D5211868

fbshipit-source-id: 6a85f7c4a543a4c9345ec5b0681a8853707343dc

Summary: Use clang-tidy to mechanically add missing `override` and remove redundant `virtual`.

Reviewed By: igorsugak

Differential Revision: D5211868

fbshipit-source-id: 4118c4c72f8ec3485507f69679f7e852b3eaeb73

Summary:
[Folly] Saner test exception in `ExceptionWrapperTest.cpp`.

Make construction do the work and make `what()` free.

Reviewed By: andrewjcg

Differential Revision: D5216707

fbshipit-source-id: bfb4c2473a61ff7da7a3a01adc85facae30d6586

Summary: Add a few more compatibility wrappers for pre-1.1.0 APIs

Reviewed By: yfeldblum

Differential Revision: D5194164

fbshipit-source-id: ae8db08c31370eca729df2927798b6f4d99ee70c

Summary: [Folly] Apply `clang-format` to `folly/gen/` (template decls).

Reviewed By: Orvid

Differential Revision: D5216229

fbshipit-source-id: 1659f1944ccde4de39bccd189bb6490395cf29c2

Summary: This is entirely the wrong way to include these headers, and is being included within an anon namespace so just wrong.

Reviewed By: yfeldblum

Differential Revision: D5215065

fbshipit-source-id: 499df58c0202f7a1d4482eaa6a0e8b2e1535c763

Summary:
[Folly] Apply `clang-format` to `folly/experimental/exception_tracer/` (headers).

With some manual rearrangement in the places where `clang-format` does awkward things, with the result that `clang-format` over the listed directory becomes a no-op.

Reviewed By: Orvid

Differential Revision: D5215212

fbshipit-source-id: 5570f02c238b1874adbc2ff4150f465c947ad0e6

Summary:
[Folly] Apply `clang-format` to `folly/fibers/`

With some manual rearrangement in the places where `clang-format` does awkward things, with the result that `clang-format` over `folly/fibers/` becomes a no-op.

Reviewed By: igorsugak

Differential Revision: D5178118

fbshipit-source-id: ae65ff1902666ba9106e18f916bb1d10e6406bf4

Summary: Otherwise downstream Windows users have to explicitly disable MSVC's warnings about unknown pragmas.

Reviewed By: yfeldblum

Differential Revision: D5211415

fbshipit-source-id: 42871e03895010818c7e1cb6e57c1885970e98c2

Summary:
Folly is a C++ library not a C library, and (almost) universally uses `nullptr` everywhere, so refer to `nullptr` rather than `NULL`.
This also fixes the 1 place in our actual code where we were using `NULL` rather than `nullptr`.

Reviewed By: yfeldblum

Differential Revision: D5204766

fbshipit-source-id: 2a5d5011a28d7d5dd48789f60643a656f51b9732

Summary: FixedString.h has a workaround for a gcc bug regarding erroneous -Werror=array-bounds errors. This commit extends the workaround to the gcc-5 series, which sadly is still broken. Life gets better with gcc-6.

Reviewed By: luciang

Differential Revision: D5210633

fbshipit-source-id: 4fcf080d18ddc573636a3e58b61a97167a8c06ce

Summary:
Make extent hooks static and avoid calling arena_destroy, in case there are
alive allocations not freed yet.

Reviewed By: yfeldblum

Differential Revision: D5208102

fbshipit-source-id: 612c772347cd90227fa303fd0b059edbaeb7d4e2

Summary:
I thought I had already implemented this, but apparently I had only implemented the ll variable. Whoops.
This implements the 32-bit version which fixes the build on Windows.

Reviewed By: yfeldblum

Differential Revision: D5203680

fbshipit-source-id: 02b133db59e232cac586944b0ffc0e8bbf5f533a

Summary: The directory contains benchmarks and multiple `main`'s so shouldn't be included as part of the main folly library.

Reviewed By: yfeldblum

Differential Revision: D5204132

fbshipit-source-id: 7289cb9c2ec292c13df39c9e7b48eca4166ca951

Summary:
[Folly] Pass `Try` by rvalue ref in `onError` implementation.

As is done in other overloads and in `thenImplementation`. For consistency.

Reviewed By: spacedentist

Differential Revision: D5199302

fbshipit-source-id: c78db0c36fc7a0b846ca5e44fc237422c9203a24

Summary: Update tuple generated for hash/equal_to for `folly::Uri` to also use std::string

Reviewed By: Orvid

Differential Revision: D5199266

fbshipit-source-id: bcd619dae01ffbf82fbb5c8987b0e87103572452

Reviewed By: anirudhvr

Differential Revision: D5193205

fbshipit-source-id: 5b427ee4f31008518078f5e54e85c0f0f2201da5

Summary:
[Folly] Shrink the implementations of `then` and `onError`.

Just a small refactor.

Reviewed By: spacedentist

Differential Revision: D5180784

fbshipit-source-id: a399d18500a2b4c5d8f24dee54891cca802b4461

Summary:
[Folly] `Try::tryGetExceptionObject`.

If the `Try` has a `std::exception` for the non-template overload or a `From` where `is_convertible<From*, Ex*>` for the template overload parameterized by `typename Ex`, returns a pointer to it. Otherwise returns `nullptr`.

Reviewed By: spacedentist

Differential Revision: D5180848

fbshipit-source-id: b7593b7459259f9a1e1e78b36d548e55d086e722

Summary:
[Folly] Remove `exception_wrapper::throwException`.

It has been renamed to `throw_exception`.

Reviewed By: Orvid

Differential Revision: D5181005

fbshipit-source-id: 442b3fd9bdaa8170db504a81651cbb085ea50624

Summary:
Add streaming interface to the ZlibCodec.
Implement ZlibStreamCodec::doCompress() and ZlibStreamCodec::doUncompress() using the streaming interface. fbgs CodecType::ZLIB and check that no caller requires thread-safety.
I found one caller, but it was fixed in D5090855.

Reviewed By: yfeldblum

Differential Revision: D5169338

fbshipit-source-id: 40478e162143623ad28fd8bc937d0195521f13fe

Summary: Using fbstring directly is not really worthwhile in the vast majority of cases, especially when most places just convert it into an `std::string` immediately.

Reviewed By: yfeldblum

Differential Revision: D5187835

fbshipit-source-id: 6f7d71612d3765e8b501d2432cd6281369bfe0fa

Summary:
Now that it's possible, let's add some 1.1.0 tests to avoid regressing
1.1.0 support

Reviewed By: yfeldblum

Differential Revision: D5167246

fbshipit-source-id: ba12414504131697d4e0757c9c340a66f810acd4

Summary: We cannot guarantee the correct destruction order of the Meyers singleton owning the allocator, and the objects allocated with it, so we just leak it using `Indestructible`.

Reviewed By: djwatson

Differential Revision: D5196227

fbshipit-source-id: ec07ab1e21af7814194883b252d45aa36d2a04b1

Summary:
[Folly] Rename `exception_wrapper::get_object` to `get_exception`.

This will be a template overload of the existing non-template member `get_exception`, but it should just work.

Reviewed By: spacedentist

Differential Revision: D5180845

fbshipit-source-id: 28e16e039ec6a7939b38f217b4ad5c6bc803f515

Summary:
- Fix TimePoint to use steady_clock rather than system_clock
- Use nanoseconds instead of milliseconds in most locations

This code should probably also be moved into a folly::testing namespace or
something.  This class is pretty specific to unit tests, and `folly::TimePoint`
seems like too generic of a name for it.  However, just to keep things simple
I'm not doing that as part of this diff yet.

Reviewed By: yfeldblum

Differential Revision: D5175630

fbshipit-source-id: 26490fc7ff1b25fb86f09309e81108828cd0f091

Summary:
Use the newly introduced getOSThreadID() function to get a thread ID for
determining thread scheduling information on Linux.

Reviewed By: yfeldblum

Differential Revision: D5173596

fbshipit-source-id: 3e6fa352c3774986b0ac1f93bd6c7e4a29e08471

Summary:
Some of the code in TimeUtil.cpp computes how long the current thread has spent
waiting to be schedule on the CPU, so we can discount this time when testing
timeout behavior.

It appears that this code has been broken for a fairly long time.  Older Linux
kernels reported values in /proc/<pid>/schedstat using jiffies.  However, it
appears that this was changed in Linux 2.6.23 to report values using
nanoseconds.  (It looks to me like this was changed in commit 425e0968a25f,
which purports to simply be moving code from sched.c to sched_stats.h,
but it appears to also have also changed this behavior.)

This updates TimeUtil.cpp to compute the value correctly in modern Linux
kernels.

Reviewed By: yfeldblum

Differential Revision: D5173598

fbshipit-source-id: 98436d3a687400bf68661156ffce93eea7232632

Summary:
Adds a core-local allocator to CacheLocality.  Multiple objects using
cache locality may share the same allocator, and allocate things less than
cacheline sized, without incurring additional false-sharing overhead.

Reviewed By: nbronson, ot

Differential Revision: D5139886

fbshipit-source-id: a9804662d6339829a12e0791f418dabd9678f1bf

Summary:
`kDecayCmd` was guarded such that it wasn't being defined at all if JEMalloc wasn't available.

Closes https://github.com/facebook/folly/issues/608

Reviewed By: interwq

Differential Revision: D5193721

fbshipit-source-id: 1a2666de70e90eac1e9f2e130d0452b01b3239fa

Summary: This diff adds a Traits template parameter to IndexedMemPool that allows more control over the lifetime management of individual elements, including mixes of lazy and eager recycle semantics (or colocation of different classes of data inside a single element). It also arranges that an index is not reported as isAllocated() until it has been passed to Traits::initialize and passed to Traits::onAllocate at least once, so code that is traversing valid indexes doesn't need to deal with the post-initialize but pre-onAllocate state (it must still deal with indexes that reported isAllocated() as true but have since been passed to onRecycle). The default behavior is unchanged.

Reviewed By: nbronson

Differential Revision: D5177462

fbshipit-source-id: e7d22c860ab6bf25083977dfb5a63955641c9cfb

Summary: MemoryMapping doesn't use fbstring directly at all, so this include isn't needed.

Reviewed By: yfeldblum

Differential Revision: D5188209

fbshipit-source-id: d86b876a96343c830295bea1162580215a340815

Summary:
The syscall() function is defined in <unistd.h>
<sys/syscall.h> apparently only defines IDs to be used with syscall(), but does
not define the syscall() function itself.

This caused build failures for files that included ThreadId.h before unistd.h

Reviewed By: Orvid

Differential Revision: D5189658

fbshipit-source-id: 2ec8ea1d58f3fc14cf458a53ecaa811978527398

Summary:
This diff adds helper functions that can resize std::string or std::vector
without constructing or initializing new elements.  They are designed
for retroactively optimizing code where touching every element twice
(or touching never-used elements once) shows up in profiling, and where
restructuring the code to use fixed-length arrays or IOBuf-s would
be difficult.

Implementations are provided for 5 string implementations (pre-c++11
libstdc++, libstdc++ with SSO, libc++, std::basic_fbstring, and MSVC)
and 3 vector implementations (libstdc++, libc++, and MSVC).  On an
unsupported platform you will hopefully get a #warn if you include
UninitializedMemoryHacks.h followed by a linker error if you actually
use it.

Reviewed By: yfeldblum

Differential Revision: D5102679

fbshipit-source-id: 536c00eabae4cdb8a0affe3e919a372f4dc51ac5