Summary: [Folly] More direct overload resolution control in `folly::coro::concat`. Just name the type directly rather than using SFINAE, when the SFINAE would just name the type directly in a more roundabout way.

Differential Revision: D18746633

fbshipit-source-id: 6da909834b511426b1cf7bbda0fd7643b5761f14

Summary:
This diff addresses a collection of issues with our thrift-py3 build story in open source.
- Cython 0.29 bug https://github.com/cython/cython/issues/2985 prevents us from loading the generated binary python extensions. I've tested 0.28.6 and it works perfectly.
- Adds ssl to the extensions (since we need SSLContext in get_client, we must have access to the module)
- No need to special case folly_pic. There is really no easy way to get the python bindings to work without using shared library libfolly.so. So, In our build (logdevice) we will build folly as a shared library, this also reduces the complexity everywhere.
- We also need iobuf as extension for thrift to work, added that to setup.py
- Refactored some of the CMake code that had hardcoded file names to use globbing to future-proof this as much as possible.
- Moved `python/lang/cast.pxd` to match the python module name `folly.cast`, so now it lives in `python/cast.pxd`. This simplifies the globbing as well.
- Moved `setup.py` to live in the `/python` directory.
- Added `*.py` in setup.py to pickup any raw python code (including `__init__.py`)

Reviewed By: yfeldblum

Differential Revision: D18685009

fbshipit-source-id: 749b30942a3e5e9e314b5248cc0aa90c6ac1581f

Summary: This is another step of moving the python extensions for folly that are currently defined in thrift's codebase. Another step for getting us closer on unblocking LogDevice to use the python3 thrift client in open-source.

Reviewed By: yfeldblum, vitaut

Differential Revision: D16221352

fbshipit-source-id: bc24fce073d67397f20f28f79c68512444704402

Reviewed By: farnz

Differential Revision: D18726052

fbshipit-source-id: 4f18430342ab6fd4fc82cc7d03e21f3e50e0ce25

Summary: [Folly] Avoid linear recursion in `folly::coro::concat`.

Reviewed By: kirkshoop

Differential Revision: D18746601

fbshipit-source-id: a383715bfc47ae8c0d4baad8799e98699c7cc14f

Summary: [Folly] Remove remnants of replacing `std::string` with the implementation of `folly::fbstring`.

Reviewed By: luciang

Differential Revision: D18738367

fbshipit-source-id: b57d38100c9da38c6351145979ac6d2f677ba817

Summary: [Folly] No unnecessary SFINAE in `ElfFile::at` - just use an explicit `static_assert` directly, rather than relying on overload resolution failure for the same goal.

Reviewed By: luciang

Differential Revision: D18746254

fbshipit-source-id: 4bb209bf3f563f2425e4532f6553e66856cb9bbb

Summary: [Folly] `try_call_once`, a nothrow variant of `call_once`. Takes a `noexcept` function which returns `bool`; the function returning `false` indicates failure and that the `once_flag` is not to be marked as as set, while the function returning `true` indicates success and that the `once_flag` is to be marked as set.

Reviewed By: andriigrynenko, luciang

Differential Revision: D18742590

fbshipit-source-id: 3b3a6fab9a328f7540cc6fee1452a0f1367b6e0f

Summary: [Folly] Let `test_once` be `noexcept` since it is required not to fail.

Reviewed By: andriigrynenko, luciang

Differential Revision: D18742588

fbshipit-source-id: fda78057d10fca1521ee6335f7c7758d05c43b88

Summary: [Folly] Hide some test helper functions to permit some tests to be linked together into the same binary, if desired.

Differential Revision: D18746529

fbshipit-source-id: 9829eb1227cb348f65734ceb670c85508577763d

Summary:
[Folly] Mark most `ElfFile` members as `noexcept`.

Since they may be used in signal handlers, they are required not to throw exceptions. Mark it so.

Reviewed By: luciang

Differential Revision: D18743292

fbshipit-source-id: 95fb2a20511ca4cc7c0e832c1b20b8324ca7d0af

Summary: The cargo builder will be used to verify if an opensource Rust project passes Cargo build, test and (optionally) documentation build.

Reviewed By: markbt

Differential Revision: D18636934

fbshipit-source-id: e982e6a017eb32913e2994e7457c8add2e9d6b95

Summary: The `accumulate` algorithm will behave similarly to `std::accumulate`, but instead returns a `Task` of the accumulated result from the values in the `AsyncGenerator`

Reviewed By: kirkshoop

Differential Revision: D18714284

fbshipit-source-id: 66625cd1347d767467d98a421b78b6f45d70260c

Summary: [Folly] Check prev thread-id in `EventBase::loopBody` to enforce that it is not called concurrently.

Reviewed By: andriigrynenko

Differential Revision: D18722163

fbshipit-source-id: 01e18758e4d517011697e025519c84e29ca96636

Summary: The `concat` algorithm will concatenate a series of streams known at compile time into a single stream of the same type.

Reviewed By: kirkshoop

Differential Revision: D18695001

fbshipit-source-id: 2da7f53cbc835333ffd9551ceae1aa5db085936d

Summary: This hadn't been updated since we moved to openssl 1.1

Reviewed By: knekritz

Differential Revision: D18668447

fbshipit-source-id: 26d58ef759fccf7e97c4d127b747b093077f6e59

Summary:
[Folly] Use `relaxed` order for `EventBase::loopThread_` consistently. There is only one location which uses a different memory order.

Atomic operations on this location do not guard any other locations, so non-`relaxed` memory orders are not required.

Reviewed By: andriigrynenko

Differential Revision: D18722614

fbshipit-source-id: b73b61e4845c34c58e9f4adbeb368c815b375d38

Summary: `folly::Function` has this explicit bool conversion operator and it makes sense to also have it for `SharedProxy`.

Reviewed By: yfeldblum, ericniebler

Differential Revision: D18504667

fbshipit-source-id: 32fede326c7a3eebd340dea9d118714a0cdfa5c0

Summary: collectAny had this overload, it was missed when collectAnySemiFuture was added.

Reviewed By: mpark

Differential Revision: D18689251

fbshipit-source-id: 1fccd6eca9d4afde46a173842641f14aff78aada

Summary: Make sure that fiber stack overflow is immediatelly discoverable from the crash stack trace, not just from the error log.

Reviewed By: spalamarchuk

Differential Revision: D18702739

fbshipit-source-id: c0a05081e67b12c94b20a929b2d10396bc1b6949

Summary: [Folly] Make `Function` shared proxy empty when constructed with an empty `Function`, just like it would be when constructed with `nullptr`.

Reviewed By: ericniebler, vitaut

Differential Revision: D18518858

fbshipit-source-id: fdad5b4cd30a1fda5465dae80054c5c74837faa9

Summary: [Folly] Let ElfFile open functions return their error messages v.s. taking pointers to where to place them. Overall, making these functions a bit more C++.

Reviewed By: luciang

Differential Revision: D18668222

fbshipit-source-id: 395c20c5d0862c2b1dcc7f6f9db56b7958c5fc90

Summary:
This diff fixes `CMakeLists.txt` to enable building `openr` tests using CMake:
1. It adds `add_openr_test` CMake function that adds executable target, registers it as test, links it with bunch of libraries like GTest and GMock, etc...
2. There is no `openr/tests/OpenrModuleTestBase.cpp` anywhere in the source tree, so this commit replaces it with `openr/common/Flags.cpp`.

Reviewed By: jstrizich

Differential Revision: D18584028

fbshipit-source-id: 07d854ef98d0d2509889a08ad042a371101a2825

Summary: Moving some `iobuf` helpers from the `thrift::py3` namespace into `folly` since this now lives in folly. Also fixing CMake to build iobuf in folly not in thrift.

Reviewed By: vitaut

Differential Revision: D16221272

fbshipit-source-id: a7bdde1b60cd6d7de06bf2040506a87c3153c37f

Summary:
Remove the Facebook-specific dependencies from the Eden manifest: these
dependencies are now available directly in the Eden repository.

Reviewed By: chadaustin

Differential Revision: D18588009

fbshipit-source-id: 590c74e38e4e05939e6955839af3ebb959f9251b

Summary:
Remove the standalone fb-mercurial-rust target that was an internal-only
dependency for the Eden build.  This build step is now done entirely in the
Eden build.

Reviewed By: fanzeyi

Differential Revision: D18623943

fbshipit-source-id: c62a1155ddd1c0a6b2270c472176ba25194c6145

Summary:
Re-implementation of fiber gdb integration.  All previous functionality still works as well.

Commands:
* `fiber`: switch to fiber by address, alias, or assigned short id
* `fiber apply`: run arbitrary gdb commands for each specified fiber (or "all")
* `fiber deactivate`: switch back to normal thread behavior
* `fiber name`: assign or clear an alias to a particular fiber
* `info fibers`: print out each fiber manager and fiber, with ids and current frame info

Parameters:
* `fiber info-frame-skip-words`: the "uninteresting" function matches to skip frames of when showing fiber info
* `fiber manager-print-limit`: limit of the number of fibers displayed when printing a fiber manager

Fibers are assigned ids of the form "<MANAGER_ID>.<FIBER_ID>".  When specifying fibers for `info fibers` or `fiber apply`, you can specify any number of space-separated fiber ids, and additionally you can specify a manager id by itself to refer to all fibers in that manager.

When printing info with `info fibers`, every stopped fiber will be in `folly::fibers::FiberImpl::deactivate()`, which isn't particularly useful.  To give more-useful information, it will skip past all frames whose function names include the strings "folly::fibers" or "wait" and print the first non-matching frame's information instead.  The `fiber info-frame-skip-words` parameter defines the strings to match on, specified as a space-separated list of words.

Due to gdb limitations, the selecting a fiber "masks" the currently selected thread, and to see the current thread again you will need to run `fiber deactivate`, same as before.

Reviewed By: andriigrynenko

Differential Revision: D18342802

fbshipit-source-id: 5b2204bb09eca4c8f977c6c17b0348e39465dff6

Summary:
- Added sai to getdeps
- added SAI to FBOSS as a dependency
- Included path of SAI headers to FBOSS's cmake file.

Reviewed By: shri-khare

Differential Revision: D18629127

fbshipit-source-id: 119a6b7f2b64bd84414d9e16a903bc8df48a35e7

Summary:
The mutable global executor is problematic: it defaults to Inline, and it is constructed off of an error-prone weak_ptr and it returns a shared_ptr. A KeepAlive-based global immutable executor is a cleaner default.

This change adds immutable global executors, and moves the default executors into separate singletons for cleaner interaction between the mutable executor and the underlying default immutable ones, including the default inline global cpu executor.

Reviewed By: andriigrynenko

Differential Revision: D18513433

fbshipit-source-id: 0ad825c34cc7ba935f57ff81adb8cff3bf001a45

Summary:
With THP set to madvise, page faults on these pages will block until a
huge page is found to service it. However, if memory becomes fragmented
before these pages are touched, then we end up blocking for kcompactd to
make a page available. As this increase pressure, oomd comes in and kills
us :(. So, preemptively touch these pages to get them backed as early as
possible to prevent stalling due to no available huge pages.

Reviewed By: hnaz, interwq

Differential Revision: D18579722

fbshipit-source-id: 5f54676a128207026cb16b9cdc03a055cbb1f9b9

Summary: This diff disables the purging of huge pages and hence they will never be freed and will be counted towards the RSS of the process. This was done to ensure that we don't block on madvise call to get the huge pages and increase memory pressure on the system.

Reviewed By: gdankel

Differential Revision: D18607196

fbshipit-source-id: 79e483a715290fdfbdd1963433ec3918561a0e0e

Summary:
Clang 7 seems to have trouble with `FOLLY_CREATE_MEMBER_INVOKER()` on Windows targets if the invoker's name is the same as the invocable name. It's spewing `-Wmicrosoft-explicit-constructor-call` warnings and the `static_assert`s in LockTraits.h are failing. As a workaround, we can rename the LockTraits.h invokers to use an `_invoker` suffix.

See https://gcc.godbolt.org/z/j4qRd9 for a demonstration of the issue.

Reviewed By: vitaut

Differential Revision: D18626335

fbshipit-source-id: c9147daaa10b02b0692c32963f9ede8cc645e329

Summary:
Include tools/lfs in the shipit path map for now, since it is needed to
download vendored Rust crates on internal builds.  Also correctly indicate
that the fb-mercurial* dependencies also apply only to internal builds.

Reviewed By: chadaustin

Differential Revision: D18621421

fbshipit-source-id: 74f00bf318ff9aefdca8696a61a8f33587749e66

Summary:
Automatically detect the `--facebook-internal` flag based on the current
repository project name.

Reviewed By: wez

Differential Revision: D18621358

fbshipit-source-id: f2b3018169b151811eec455863a8bfc17667d4d8

Summary:
Dovetailing off of https://github.com/facebook/folly/issues/1262 ; Folly's dependency on `fmt` isn't explicitly mentioned nor are from-source install instructions provided. This PR adds a short section to the README describing how to build and install fmt from source.
Pull Request resolved: https://github.com/facebook/folly/pull/1263

Reviewed By: vitaut

Differential Revision: D18622693

Pulled By: yfeldblum

fbshipit-source-id: e43ab8c5524df9decc79cdd0cb2aea3d88826617

Reviewed By: yfeldblum

Differential Revision: D18614792

fbshipit-source-id: 9b77ae8aba9153c9051dd5935cda807dfad4e6e2

Summary: [Folly] `FOLLY_CREATE_STATIC_MEMBER_INVOKER`, for creating invoker types which can invoke class static members.

Reviewed By: vitaut

Differential Revision: D18035183

fbshipit-source-id: 2bcab988f684042b26843d5fe0a13ad7c549e43a

Summary:
Since D18140137 `reset()` doesn't perform any data reads, so we can simplify the implementation of the `jump*` functions to just reset the reader in case of a backward jump. The only tricky case we need to handle is when `jumpTo` is called from the middle of a run of identical values.

Delegating to `skip*` the additional benefit of inheriting the optimizations for small forward skips.

Differential Revision: D18496743

fbshipit-source-id: 73dc8b21534fba90f1ac2a924a7cebc56ffaba94

Summary: [Folly] `to_narrow`, for explicitly performing a possibly-narrowing integral conversion without specifying the destination type. Does not permit changing signs.

Reviewed By: luciang

Differential Revision: D18498269

fbshipit-source-id: be597daf981376758effa0b3721cad67a49c9ef1

Summary:
1) SharedPromise is semantically a regular Promise one can get multiple Futures off. One would expect that all methods which are const in Promise to also be const in SharedPromise - but they are not because their implementations needs using a mutex.
2) Semantically, `SharedPromise::getFuture()` and `SharedPromise::getSemiFuture()` do not change the observable state of the object.
3) As real-life consequence,  these non-const `SharedPromise` methods become viral in downstream code which then has to hack around it in downstream `const` methods by marking the SharedPromise instance mutable. That solution leads to the program being less const-correct than it should be, as now the type system allows `const` methods to reassign or `setValue` the SharedPromise.

This diff changes `hasResult`, `isFulfilled`, `size()`, `getFuture()` and `getSemiFuture()` to be `const`. In order to achieve that, the private fields `mutex_` and `size_` had to be marked `mutable`.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D18565877

fbshipit-source-id: ff63a48c02235f72c5b0191423ae68f7b7c42fb3