Summary:
`folly::expected_detail::Promise<Value, Error>` won't build with exceptions
turned off (e.g. by passing `-fno-exceptions` on Clang's command line) because
its `unhandled_exception()` says `throw;`.  This diff replaces the `throw;`
with a call to `folly::rethrow_current_exception();`.

Reviewed By: yfeldblum

Differential Revision: D21682605

fbshipit-source-id: 294752590d54b0671395982ccdeb0386a742c01e

Summary: [Folly] Use `RequestToken` in `RequestEventBase` to speed up lookup.

Reviewed By: zhxchen17

Differential Revision: D21529465

fbshipit-source-id: eaaef7b48be2c5a8d76fb5f4a5293f7db7e68bed

Summary: [Folly] Fix technical typo in checking hw checksum support, but which makes no practical difference.

Differential Revision: D21689112

fbshipit-source-id: 8ad71d20a561f4bbf5c413ce94e7bec227d9d940

Reviewed By: yfeldblum

Differential Revision: D21666740

fbshipit-source-id: 96975e777df0745f343c5b722f1d8c05bb8ac32e

Summary: [Folly] Tweak `BlockingContext` in various ways.

Differential Revision: D21657789

fbshipit-source-id: 4b03b3b43dddc0e9011a7594001994f2594a1a5b

Summary:
[Folly] Lock utilities: `upgrade_lock`, `transition_to_shared_lock`, `transition_to_upgrade_lock`, `transition_to_unique_lock`, `try_transition_to_unique_lock`.

Note: `std::shared_mutex` does not have an upgrade state or any atomic transitions; there is no `std::upgrade_lock`; and `std::shared_lock` does not have a constructor from `std::unique_lock`.

Reviewed By: simpkins, nbronson

Differential Revision: D15532568

fbshipit-source-id: d32f387b26b57539857922c3090dc75ffcaaa538

Summary:
Migration from Future-returning executor-erasing collectX forms to
SemiFuture-returning forms, that are less risky in particular with coroutines.

Earlier changes added collectXSemiFuture and collectXUnsafe as a migration
path. We then migrated collectX callsites to collectXSemiFuture or
collectXUnsafe and switched the implementation of collectX to the SemiFuture
form.

This diff removes collectXSemiFuture completely.

Reviewed By: yfeldblum, mpark

Differential Revision: D21631886

fbshipit-source-id: c7b296d51f30c8b51ab0c7d06b1ce62c8cdd28d5

Summary:
`folly::detail::OptionalPromise<Value>` won't build with exceptions turned off
(e.g. by passing `-fno-exceptions` on Clang's command line) because its
`unhandled_exception()` says `throw;`.  This diff replaces the `throw;` with a
call to `folly::rethrow_current_exception();`.

Reviewed By: yfeldblum

Differential Revision: D21655976

fbshipit-source-id: 5f431372f2494a09f98e3b8c36a94e8475efff29

Summary:
This fails to build on win32 platform with:
```
xplat\folly\portability\pthread.cpp(142): error C2664: 'HANDLE CreateThread(LPSECURITY_ATTRIBUTES,SIZE_T,LPTHREAD_START_ROUTINE,LPVOID,DWORD,LPDWORD)': cannot convert argument 3 from 'DWORD (__cdecl *)(void *)' to 'LPTHREAD_START_ROUTINE'
```

This seems to fix it.

Reviewed By: Orvid

Differential Revision: D21623386

fbshipit-source-id: 1b18a74bd71ffc75f34a92074e07f3d69742c07d

Summary: [Folly] Small simplification of `AsyncSocket` read loop.

Differential Revision: D21514325

fbshipit-source-id: 0af27205b4aa2807a800430e8a2b3dea36356970

Summary: Add io_uring_submit_and_wait call

Reviewed By: yfeldblum

Differential Revision: D21653382

fbshipit-source-id: 945aa877a30b3c6431089a113ece5999d1217eb4

Reviewed By: yfeldblum, luciang

Differential Revision: D21656746

fbshipit-source-id: 5e19d72ccd524926c698b8814cc6c8f2c6133565

Summary: fsync the temp file

Reviewed By: yfeldblum, kevin-vigor

Differential Revision: D21668049

fbshipit-source-id: 85825f81dfbe10a452f7f946133bb3d8993850f8

Summary: [Folly] `rethrow_current_exception`, a `-fno-exceptions` compatibility wrapper for `throw;`.

Reviewed By: ispeters

Differential Revision: D21656269

fbshipit-source-id: 8f37fe71c6255162b8f05268cae04ac5927013d7

Summary:
gcc-6.5 on OS X <= 10.6 complains about the `\r` when this code path
is enabled. I don't think we officially support `__i386__`, but I want to
backport the patch from zstd. https://github.com/facebook/zstd/pull/1418

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum, Orvid

Differential Revision: D13104652

fbshipit-source-id: 737a68253c7d90c3a1cc026069b048551cb5ced9

Summary:
If an error is thrown when formating arguments for a log message, use
`folly::exceptionStr()` to format the exception instead of just `ex.what()`.

I changed all of the tests that verify the results of these strings to use a
regular expression, as `folly::exceptionStr()` produces different results in
different platforms, and does not always demangle type names.

I also included a minor change to increase a timeout in
AsyncFileWriterTest.cpp, as I saw this timeout fail spuriously once in my
testing.

Reviewed By: yfeldblum

Differential Revision: D21635680

fbshipit-source-id: 749ef48deb59af1f2faef0158e0291838e09fc38

Summary:
Fix the issue that there may be other tags like DW_TAG_lexical_block between DW_TAG_subprogram and DW_TAG_inlined_subroutine.

Also increase the maximum inline location info per frame since previous value 3 is too small.

Refactors the code to set file and line for inline functions.

Reviewed By: luciang

Differential Revision: D21250080

fbshipit-source-id: f52dc74ee5c144aa26723546b48486f8a5250f19

Summary: Fix uninitialized maxSubmit_, maxGet_ member variables

Reviewed By: danobi

Differential Revision: D21645171

fbshipit-source-id: 094ba7b045010954fdebc249318191f956f5b7b2

Summary:
This updates the logging code so that it is possible to include `folly/xlog.h`
and write log statements in code that is compiled with `-fno-exceptions`

The code for parsing log configuration strings does still use exceptions in
some of its config parsing logic.  It shouldn't be too difficult to disable
that in a subsequent diff, but for now this change at least makes it possible
for calling code to write log messages.

Reviewed By: yfeldblum

Differential Revision: D21630914

fbshipit-source-id: ce9ed422f40066e57433a85182e1a8fc6d8628db

Summary:
This fixes a race condition detected by ThreadSanitizer.

The thread list is protected by a mutex, but individual structs in the list are not protected, leading to racy access to two of their fields. This diff makes the fields atomic.

Reviewed By: yfeldblum

Differential Revision: D21484748

fbshipit-source-id: a981419f47a2aebaf1d40b23e9c4967cf2104aaa

Summary: Remove PollIoBackend inline submit

Reviewed By: danobi

Differential Revision: D21625033

fbshipit-source-id: 02ee55e64a2538c6a2392ea70912f4ae9b642963

Summary:
The current stack trace formatting is based on repeated string appends with newlines. This change adds more control so that we can produce file and line information only, without unnecessary newlines.

New format:
  ./folly/experimental/symbolizer/Symbolizer.h:77
  ./folly/experimental/symbolizer/test/StackTraceTest.cpp:209
  ./folly/experimental/symbolizer/test/StackTraceTest.cpp:213
  ./folly/experimental/symbolizer/test/StackTraceTest.cpp:258

Reviewed By: yfeldblum

Differential Revision: D21562670

fbshipit-source-id: 7d05605cbda686e2f1c87577647c7ab7581f8580

Summary:
adds ensureCleanupAfterTask()

takes a SemiFuture<T> task and a SemiFuture<Unit> cleanup.

returns a SemiFuture<T>

always starts cleanup after task completes. stores the result of the task and replays it after the cleanup completes.

cleanup is not allowed to fail.

Reviewed By: yfeldblum, andriigrynenko

Differential Revision: D21481825

fbshipit-source-id: 901a91c25f7b2b4fa794a590a5433e0fad27d168

Summary:
CpuLocalBuffer need extend alignment, which isn't honored by std::vector's default allocator due to compiler bug

  http://open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3396.htm
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65122
  https://bugs.llvm.org/show_bug.cgi?id=22634

the fix is to use custom allocator to honor extend alignment requirement.

Reviewed By: yfeldblum

Differential Revision: D21405041

fbshipit-source-id: 53cfe1bfd66580990c8a1a0c5f0c09f6651bda24

Summary:
[Folly] Fill `reentrant_allocator` member types and functions for situations which fail to indirect via `std::allocator_traits`, such as the former implementation of libstdc++ `std::basic_string`.

May help to address https://github.com/facebook/fboss/issues/86.

Differential Revision: D21608091

fbshipit-source-id: 020ac3bd37b27a08dd7c8113a77979d0ba21a8fc

Summary:
Allows attaching a BPF script to observe tasks behavior

Sample script, attaching those probes to a test binary (./buck-out/gen/common/services/cpp/test/thrift_2_async_server) is provided.

Reviewed By: yfeldblum

Differential Revision: D21526163

fbshipit-source-id: e976ddada1921c8c904d65aa9a558bbb45bf158f

Summary:
Adds a new CoInvoke() helper function that should be used instead of ::testing::Invoke() when defining mock methods using coroutine lambdas.

Use of Invoke() in a GMock definition that calls a coroutine-lambda that
contains captures will result in the returned Task holding a dangling reference
to a copy of the lambda.

The CoInvoke() helper instead, ensures that the coroutine created by the
lambda holds on to a reference to a copy of the lambda that is kept alive
until the coroutine completes by invoking the lambda using the folly::coro::co_invoke()
utility function instead of directly calling operator().

Reviewed By: andriigrynenko

Differential Revision: D21578404

fbshipit-source-id: 3322740efd00596c2311530a166ef2d5301c6b89

Summary:
I'm doing this mostly so that we can avoid using git
to fetch the sources.

Reviewed By: chadaustin

Differential Revision: D21508201

fbshipit-source-id: 54d4635d8938659bea962e90bd829d237f1ed221

Summary:
We use drive letter substitutions to workaround Windows
filename length limitations.  On my personal Windows system running
python 3.8.2 realpath inside an ssh session manages to resolve to
the full filename which causes the boost build to fail.

Avoid that!

Reviewed By: chadaustin

Differential Revision: D21507851

fbshipit-source-id: 1220c1c85d2124ddc51f42cefff2ce00e10c55c9

Summary: [Folly] Avoid inlining `Cursor` slow paths. These are already extracted to separate functions, but the compiler will still aggressively inline them.

Differential Revision: D21392842

fbshipit-source-id: 2b045ae9c5188315b938de984730ad2051237cf5

Summary: Giving SSLContext ownership over the new session callback attached to SSL_CTX, so that it may do additional work with the new session (i.e. forward the session to its corresponding abstracted SSLSession).

Reviewed By: mingtaoy

Differential Revision: D21478165

fbshipit-source-id: 459e4b3f9af2fedee4c02df6c9f689db15c1852f

Summary: Avoid calling scheduleTimeout for a thread that is mostly busy

Reviewed By: yfeldblum

Differential Revision: D21531280

fbshipit-source-id: b89254ebc3662c951b3b181b3a2777afb9e3f4fe

Summary:
As it turns out, to use this reliably on Android we need to define a weak symbol. The headers are only exported after API level 21, so apps that compile with 16 cannot use it with a compile time flag.

Instead we can utilize a weak symbol to link with it, and check if it's there at runtime.

Reviewed By: yfeldblum

Differential Revision: D21535034

fbshipit-source-id: 8b68a803d1e9f2f293e9f3efa16fb2a18abee53d

Summary:
[Folly] Explicitly enforce that `RequestToken` is trivially-destructible to permit its use as a Meyers Singleton without requiring the use of Leaky Meyers Singleton to avoid destruction-order problems.

(Note: this ignores all push blocking failures!)

Differential Revision: D21533605

fbshipit-source-id: fe334fd5257b1d0a07efd849c4532b28801e54c4

Summary: Adds a version of getFiberManager that takes a VirtualEventBase + FrozenOptions

Reviewed By: yfeldblum

Differential Revision: D21507009

fbshipit-source-id: 2bffd1704650b25e78fc388b3e033da4f2c16b9a

Summary: It needs to set the msg_len, otherwise the caller doesn't know how long the datagram is.

Reviewed By: yangchi

Differential Revision: D21512788

fbshipit-source-id: f24c2bd9e86acf93ebf12c48afcf7658c8e8d54e

Summary: Fix sendmmsg wrapper

Reviewed By: yfeldblum

Differential Revision: D21513176

fbshipit-source-id: ddc1bdd93801136994ef62fd5793da7371e9e22a

Summary:
This diff adds support for reference types to the Async abstraction.

One example use-case is memoization where you generate the value asynchronously on cache-miss. You want may want to return a reference to avoid the expense of copying.

Some additional context is in D21438851.

Reviewed By: yfeldblum

Differential Revision: D21478238

fbshipit-source-id: 53e1b997abed2d40f0a2f9ab935925ad9bbc91ab

Summary:
VirtualEventBase is backed by a EventBase and byitself is also sequenced, thus shoudl be an SequencedExecutor

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D21493098

fbshipit-source-id: 97fd09161117e77422a5786584db89af98dfe314

Summary:
For large projects, with lots of tests, running all the tests can take a lot
of time, but for quick development iteration, only a subset of the tests may
be needed to run.

On non-Windows platforms, this can be easily achieved by manually executing
the individual tests binaries and use the builtin filtering mechanism of that
test binary to achieve the goal. On Windows, this can quickly become
impossible as DLLs might not be available, and the right PATH would need to
be manually specified by hand to execute the tests binaries[0].

To solve this, let's simply provide a unified way of running specific tests
by passing in a regexp. Both testpilot and CTest do support regex to execute
specific tests. My understanding is that cargo doesn't yet allows regex, but
will in the future.

[0]: And a missing DLLs would produce no output when executed from
     PowerShell, which makes this very confusing.

Reviewed By: wez

Differential Revision: D21484774

fbshipit-source-id: ee32e950e25bb2a498a2b364a447955a917b0590