Summary: This adds a file-level comment that explains the various usages.

Differential Revision: D16259169

fbshipit-source-id: 95e5e8f047cdd159899cab47c390a7b0ab8d70cb

Summary:
gcc 9's libstdc++ moves the definition of _M_impl._M_finish
into a new intermediate class. It's still addressible with the same name,
but the type of the member pointer changes. This diff switches to using
decltype to tolerate both the old and the new implementation.

Reported as issue https://github.com/facebook/folly/issues/1223

Reviewed By: yfeldblum

Differential Revision: D17283175

fbshipit-source-id: 9c9da28b83c3cb3584d33575b462d10b17002edb

Summary: [Folly] No mutable flags in IOBuf to avoid races when invoking `const`-qualified members concurrently.

Reviewed By: simpkins

Differential Revision: D17251909

fbshipit-source-id: e52d333fb620d05f7229a11db9c2f14fe9f6f028

Summary:
[Folly] Avoid ambiguous call in futures. Because `std::atomic` is in `namespace std`, unqualified calls to `atomic_compare_exchange_strong_explicit` from within `namespace folly` are ADL-ambiguous between the overloads in `namespace std` and in `namespace folly`.

Also:
* Fix incorrectly-named prototype.
* Fix used of `std::atomic<T>::value_type` which may not exist.

Fixes #1221.

Reviewed By: aary, Orvid

Differential Revision: D17256763

fbshipit-source-id: ffcaf171e6257cdef29de0ffb63f310d7f4a93eb

Summary: Making a new ctor so that we can pass in the parameters

Reviewed By: yfeldblum

Differential Revision: D17173662

fbshipit-source-id: ab518892694e1bec1179177e7d9477e3a89ff38d

Summary:
Compiling folly on Arch Linux triggered a few platform-specific behaviors that were not covered correctly by tests.

- Fix F14{Map,Set} maxSize test cases
    The maximum size of `F14Table` is dependent of its allocator's max_size:

    ```
    max_size() -> std::min<std::size_t>(
        (std::numeric_limits<InternalSizeType>::max)(),
        AllocTraits::max_size(a)
    )
    ```

    This commit fixes the `F14{Map,Set}` maxSize tests, so they won't fail
    on platforms where the standard allocator's `max_size()` is based on
    `ptrdiff_t` (signed).

-  Fix TestUtilTest
    If glog is compiled without gflags support, `SetCommandLineOptionWithMode()`
    can't force glog to use stderr.

    glog has its own compatibility layer for `FLAGS_*` in case gflags is missing,
    that's why `FLAGS_logtostderr` is always available.

- Skip AsyncIOTest tests if O_DIRECT is not supported by the file system
    `fs::temp_directory_path()` returns `"/tmp"` on Linux.

    When using systemd, the /tmp directory is mounted by default as tmpfs;
    and tmpfs does not support the `O_DIRECT` flag.

    This commit skips tests in case the file can't be opened with `O_DIRECT`.
Pull Request resolved: https://github.com/facebook/folly/pull/1218

Reviewed By: nbronson

Differential Revision: D17160597

Pulled By: yfeldblum

fbshipit-source-id: 00274d1f8770079e35559ee9bd8426402e949abd

Summary: [Folly] Switch from `-defs.h` pattern to `-inl.h` pattern in `folly/stats/` since `extern template` doing shallow instantiation rather than deep instantiation makes this pattern difficult.

Reviewed By: chadaustin

Differential Revision: D16761319

fbshipit-source-id: 1760bf53b09791bebf996064c0d1fcc3babf43d2

Summary: [Thrift] Bake templates into the compiler binary rather than having to package the templates with the compiler.

Reviewed By: stevegury, vitaut

Differential Revision: D16356056

fbshipit-source-id: b971dce7aada8dc2a26587fbf818e661acd0c555

Summary:
[Folly] Extract compare-exchange hack under TSAN to a common location and make its interface mimic `std::atomic_compare_exchange_strong_explicit`. Limit it to Clang TSAN (no knowledge of whether it applies to other implementations of TSAN), but extend it to handle all pairs of success and failure orders.

The TSAN bug is described in https://github.com/google/sanitizers/issues/970. High level, Clang TSAN ignores the explicit failure order and infers a failure order from the success order - which is broken if the explicit failure order is in the relevant sense stronger than the success order.

Reviewed By: aary, nbronson

Differential Revision: D16854217

fbshipit-source-id: 18f6458520bbd5f482e41c10d7229e6cfae1db2a

Summary:
This should make it easier to eg: enable fbzmq on macos at a later
time, and also makes things more explicit about what is being built, and
importantly, by listing these in the manifest ensures that we have a
hash change if we change this list; we wouldn't trigger such a change
if the list were encoded solely in builder.py

Reviewed By: chadaustin

Differential Revision: D17133149

fbshipit-source-id: caf0dd45e262188eeefafe0868ef95ad257a4950

Summary:
* Fix a minor issue with `add_fb_python_executable` where it would
  emit `--main` even if `MAIN_MODULE` had not been specified
* Introduce the ability to rename python sources in the manifest so
  that they have a different install path.
* Note that this changes the DEPENDS parameters to reference abs_sources;
  previously these were using relative paths to the sources pulled directly
  from the SOURCES arguments, but since those can now contain aliasing
  operations we need to pre-process the list.  I switched to abs_sources
  because that was already being maintained.  If for some reason the
  DEPENDS list needs to be relative paths, this will need to be adjusted.

Reviewed By: simpkins

Differential Revision: D17147417

fbshipit-source-id: d0825bfbdad6be658c078aaac6645e6926a1530f

Summary:
This diff adds a small abstraction that allows for uploading
and downloading from an artifact cache.

We try to download from this cache at build time, but will only
try to populate it for continuous builds--those are built from
code that has been reviewed and landed on master.  This restriction
helps to avoid thrashing the cache with works in progress and
results in a slightly more trustworthy state of the cache contents.

In addition to this, we choose only to cache third party projects.
The rationale is that our first party projects move too quickly to
be worth caching, especially since the cache granularity is for
the whole project rather than just changed elements of a given
project.

In a later diff I will introduce some implementations of the
cache class that work with eg: Travis or Circle CI caching.

Reviewed By: simpkins

Differential Revision: D16873307

fbshipit-source-id: 2bfb69e36615791747b499073586562f2ca48be9

Summary: one_ms is short enough that it can trigger under testing. Increase to make less likely to fail spuriously.

Reviewed By: yfeldblum

Differential Revision: D17190402

fbshipit-source-id: 091cd3ee8f3da224e39ba95c403e233115a80510

Summary: SemiFuture::within was undocumented and Future::within's use of the term "throws" was confusing. This cleans up both sets of documentation.

Reviewed By: yfeldblum

Differential Revision: D17186392

fbshipit-source-id: 83409df85b07bd3cad9fb020e99fc3a7f3c70b61

Summary: Disable FOLLY_TLS under 32 bit Apple/iOS

Reviewed By: mzlee

Differential Revision: D17172252

fbshipit-source-id: ab47bb9ddb810aec45a940fc2ae834bac6a48f7c

Summary:
> Under the following circumstances, the compilers are permitted to omit the copy and move construction of class objects:

> In a return statement, when the operand is the name of a non-volatile object with automatic storage duration, which isn't a function parameter or a catch clause parameter, and which is of the same class type (ignoring cv-qualification) as the function return type. This variant of copy elision is known as NRVO, "named return value optimization".

`std::move()` prevents this optimization.

GCC 9.1.0 warning:
```
moving a local object in a return statement prevents copy elision [-Wpessimizing-move]
```
Pull Request resolved: https://github.com/facebook/folly/pull/1217

Reviewed By: LeeHowes

Differential Revision: D17173234

Pulled By: yfeldblum

fbshipit-source-id: ed63ef89dfd01883ddd6fd775285997f96a029fd

Summary: [OpenSource] Cut `mstch` manifest, which was but is no longer used by `fbthrift`.

Reviewed By: avalonalex, davidtgoldblatt

Differential Revision: D17160816

fbshipit-source-id: 3b96142455d6990870e8ed3e5ce330d339d5a657

Summary:
Feed the first-party oncall data through to the testpilot
invocation.  This will set the owner of the test in continuous runs.

The oncall is passed through via the sandcastle module, which means
that you will have to manually pass it through for local testing
(see test plan), but it should automatically get picked up when
sandcastle schedules the `test` step of the job.

Reviewed By: chadaustin

Differential Revision: D17146802

fbshipit-source-id: a4f0e65853a46ed8709594c96db859ede2530b00

Summary: when trying to build openr with `getDeps.py` constant definitions where not available since they were not part of the generated thrift lib. this fixes it.

Reviewed By: chadaustin

Differential Revision: D16064417

fbshipit-source-id: ee2b3e061caf67235f4a873405cf6cd6fb663ef4

Summary: This algorithm multiplexes values from a stream-of-streams into a single stream of events that identifies the stream index the event originated from and also the end-of-stream and stream-error events.

Reviewed By: lewissbaker

Differential Revision: D15643142

fbshipit-source-id: a309a485f11465d9068ea81f4bc32823dd34291f

Summary: The `transform()` algorithm uses the provided function to transform each value in the provided input stream and produces each transformed value on the returned output stream.

Reviewed By: lewissbaker

Differential Revision: D16774893

fbshipit-source-id: 7ab33706c667b1706c0cb0b1c0ecb9046f47a325

Summary: Adds a new `folly::coro::merge()` algorithm that accepts an async stream of async streams and returns an async stream that merges and interleaves the results.

Reviewed By: lewissbaker

Differential Revision: D15617383

fbshipit-source-id: cafb8e31725cdb21cfa00ce186901329828c2b68

Summary: fixes the CI build

Reviewed By: dddmello

Differential Revision: D17158685

fbshipit-source-id: 44ea871eab4d8c964b8372fb8d84879fa823ca50

Summary:
Range-v3 v0.9.1-pre deprecated and renamed a bunch of interfaces to harmonize with the direction of C++20's `std::ranges`. In this diff, I:

* Rename the `ranges::view` namespace qualification to `ranges::views` (plural),
* Rename the `ranges::action` namespace qualification to `ranges::actions` (plural),
* Rename `ranges::view::bounded` to `ranges::views::common`,
* Rename `ranges::to_` to `ranges::to`,
* Replace _some_ implicit conversions of views to containers with explicit invocations of `ranges::to` (more work to be done here, but can wait).

Reviewed By: mzlee

Differential Revision: D17061465

fbshipit-source-id: f28205ecf3965d3560e9cffe2805d0b404597b21

Summary:
Remove calls to Future::then(executor, callback).

This form of Future::then is ambiguous, and does not yet implement the stronger
typing of thenValue and thenTry. It is also tempting to use instead of via,
where it is not obvious that it has the behaviour of wrapping a via call in a
push and pop of the current executor:
.pushCurrentExecutor().via(executor).then(callback).popCurrentExecutor().

With the addition of inline continuations, we can instead make the nesting
explicit at low cost by making it an inline continuation that launches an
asynchronous task on the passed executor.

Reviewed By: yfeldblum

Differential Revision: D15100419

fbshipit-source-id: e929e2eaf2fc30313cb099150be3a9535ae729a6

Summary:
TimeKeeper::after and TimeKeeper::at return Futures that for the majority of implementations complete on a TimeKeeper owned executor. This can lead to problems.

Consistent with other API cleanups, this diff switches TimeKeeper APIs to return SemiFuture, requiring that the caller attach an explicit executor when work is to be scheduled downstream of the TimeKeeper.

Reviewed By: yfeldblum

Differential Revision: D17005944

fbshipit-source-id: 98d7e8aaf1ad40ce2180503f632f2f0003bb12be

Summary: Under some circumstances the DeferredExecutor might already have nested executors and this code adds more. Both incoming futures should instead nest within a fresh DeferredExecutor returned that is part of the SemiFuture from the operation.

Reviewed By: mpark

Differential Revision: D17121117

fbshipit-source-id: b4507bf5d7b0c98e5e5de6f73ff4bd3e2790374c

Summary:
[Folly] RTM re-nits for `xabort`.

* Remove param pack.
* Always noreturn.

Reviewed By: nbronson

Differential Revision: D17117350

fbshipit-source-id: b16056b1f02956d334da4494c689a4b988a961d4

Summary:
The `materialize()` algorithm meterializes values from a stream into a stream of events that represent each value and also the end-of-stream and stream-error events.

`dematerialize()` reverses a materialized stream by replaying the events recorded in the input stream to an output stream.

Reviewed By: lewissbaker

Differential Revision: D16772236

fbshipit-source-id: 27de543ea2d02691a376fd0f11d0113c5c39287d

Summary:
boost.fiber is not available on macos and is required by fbzmq,
so disable the build on darwin.

In D17128935 I tried to make libzmq build with cmake to build
on windows, but there's a problem with its cmake and it fails
to configure.

So let's just nop out the build for !linux for now.

Reviewed By: jstrizich

Differential Revision: D17129362

fbshipit-source-id: db89010d18707a4105b8d395b1758f738336495d

Summary:
In order to foster healthy open source communities, we're adopting the
[Contributor Covenant](https://www.contributor-covenant.org/). It has been
built by open source community members and represents a shared understanding of
what is expected from a healthy community.

Reviewed By: josephsavona, danobi, rdzhabarov

Differential Revision: D17104640

fbshipit-source-id: d210000de686c5f0d97d602b50472d5869bc6a49

Summary:
This module provides a `add_fbthrift_library()` convenience function that can
be used to generate thrift libraries for multiple languages with a single
call.

Reviewed By: wez

Differential Revision: D16742275

fbshipit-source-id: c13120cf9e051629951282141eb22f3e085782f9

Summary:
This module helps generate Python libraries from thrift files.
It is the Python equivalent of `FBThriftCppLibrary.cmake`

Reviewed By: wez

Differential Revision: D16742274

fbshipit-source-id: ef0dc7f24eb1c7375d2587ee6b71fd25bd6f35a7

Summary:
Fix a minor bug in the argument parsing for `add_fbthrift_cpp_library()`:
only a single value should be supplied for the `THRIFT_INCLUDE_DIR` argument.
This parameter should not accept a list of arguments.

Reviewed By: strager

Differential Revision: D17125810

fbshipit-source-id: 31f354e4d6299d3626a94f3b4b5ff8c58bb0cf7b

Summary:
An AsyncGenerator coroutine now has an implicit associate CancellationToken that is inherited from the calling context of each `co_await gen.next()` call.

This means that generators that correspond to long-running subscriptions now have an in-built channel that allows them to cancel the subscription.

This is also useful for algorithms that introduce concurrency in processing of stream data. eg. The `buffer()` or `merge()` algorithms.

Reviewed By: kirkshoop

Differential Revision: D16833864

fbshipit-source-id: be8faf1ec438c4248091e02d6a264d3760e2d73d

Summary:
Pull Request resolved: https://github.com/facebook/folly/pull/1212

MSVC has a bug and can't match definitions of some of the constructors to the corresponding declarations in a class body. This diff workarounds the bug by inlining constructors.

Reviewed By: LeeHowes

Differential Revision: D17119718

fbshipit-source-id: eb7a9d4916b962c718d047eb0ee7fa4a9761776e

Summary:
The `collectAll()`, `collectAllRange()` and `collectAllWindowed()` functions now cancel their subtasks when either the parent task is cancelled or when any of the subtasks fail with an exception.

The `collectAllTry()`, `collectAllTryRange()` and `collectAllTryWindowed()` functions now cancel their subtasks if the parent task is cancelled, but not if the child tasks fail with an exception.

The logic between the distinction here is that if you are calling one of the 'try' functions then you are intending to handle partial failure and so probably want each of the operations to run to completion independently of the others.

Reviewed By: kirkshoop

Differential Revision: D16820619

fbshipit-source-id: 5c203b41592a0145ff7be1c609dfccd39c41a3df

Summary: `clang-cl` on Windows also defines `__PRETTY_FUNCTION__` which has a format different from `__FUNCSIG__`. Therefore folly breaks users of this macro. Alias should be defined only when "real" MSVC compiler is used.

Reviewed By: akrieger, Orvid, blackm00n

Differential Revision: D17094657

fbshipit-source-id: 4b191a61201704382e6b6e178bcc1c673511c537

Summary:
Rename the `ThriftCppLibrary.cmake` file to `FBThriftCppLibrary.cmake`, and
also rename `add_thrift_cpp2_library()` to `add_fbthrift_cpp_library()`.

Explicitly calling this `fbthrift` helps clearly distinguish that this is
intended for use with fbthrift (https://github.com/facebook/fbthrift/), as
opposed to Apache thrift.

Reviewed By: wez

Differential Revision: D16738440

fbshipit-source-id: 9b255e06b71c98ad74a34989f564a211958dcdd5

Summary:
CacheLocality's parsing code for /proc/cpuinfo doesn't properly
handle systems in which there are offline CPUs. This diff makes it so
we fall back onto the sequential cache locality implementation in the
problematic scenarios.

This should address https://github.com/facebook/folly/issues/1208

Reviewed By: shixiao

Differential Revision: D17093176

fbshipit-source-id: 4da3a9dc53622f829af37ed70a2531c66fd92ddb