Summary:
This diff adds fb303 dependency to Open/R. fb303 is FB's open-sourced project
which provides basic infrastructure for thrift service e.g. base functions,
counters supports etc.

Using this in Open/R will allow both internal & external users leverage counters
via thrift APIs

Reviewed By: xiangxu1121

Differential Revision: D20134243

fbshipit-source-id: 23782ec99dc749dd27dc19f2b2b023f1c229608b

Summary: Adds a few simple benchmarks to get an idea for the overhead of `folly::coro::Task` coroutines.

Reviewed By: yfeldblum

Differential Revision: D19729527

fbshipit-source-id: cdfbd5c408c24dd258c56bc159af0c03cb1cd55e

Summary: As a step to eventually supporting TLS 1.3 by default for OpenSSL, we want to add the ability to selectively enable TLS 1.3 in folly::SSLContext.

Reviewed By: mingtaoy

Differential Revision: D20102778

fbshipit-source-id: 0865821ad2730482e797b888d16561b6989dca62

Summary: We should probably just free this.

Reviewed By: yfeldblum

Differential Revision: D20119718

fbshipit-source-id: 2a6c79730243b7af5ba90dac631ce0c8e1e0e6a4

Summary: Add API to Set Socket Option for AsyncUDPServerSocket.h, which is the same as AsyncUDPSocket.

Reviewed By: yfeldblum, lnicco

Differential Revision: D20064430

fbshipit-source-id: d448fbc217d0098e0ab94e2f113d4eba97958b02

Differential Revision: D19882830

fbshipit-source-id: 031217f9890351022bc8d171f0ccd7e045dd6972

Summary: Workaround for a TSAN fork deadlock

Reviewed By: kevin-vigor

Differential Revision: D20107616

fbshipit-source-id: df4d6222f63131e49fc1e831ec81d6441269b1f4

Summary: Sanitizers always intercept the allocator, so there's no reason to do the elaborate `usingJEMalloc()` logic -- it will always fail.

Reviewed By: yfeldblum

Differential Revision: D20056781

fbshipit-source-id: c0d4a3b103e26bacc0a6589f8d54b4a2ec85f771

Summary: This makes the function name more accurate. The function does not start the thread pool executor. It only enables the construction and use of a thread pool executor by the default hazptr domain when needed.

Reviewed By: davidtgoldblatt

Differential Revision: D19852860

fbshipit-source-id: 5ae71d0fd2d2d20c9ca66f45d57e90085703b3fb

Summary:
clang fails to optimize the current version even in the opt mode

code:
```
void clear(folly::small_vector<int, 5>& vec) {
    vec.clear();
}
```

before:

cat_huh

```
0000000000000000 <clear(folly::small_vector<int, 5ul, void, void, void>&)>:
   0:	55                   	push   %rbp
   1:	48 89 e5             	mov    %rsp,%rbp
   4:	41 57                	push   %r15
   6:	41 56                	push   %r14
   8:	53                   	push   %rbx
   9:	50                   	push   %rax
   a:	49 89 fe             	mov    %rdi,%r14
   d:	48 8b 07             	mov    (%rdi),%rax
  10:	48 8d 4f 08          	lea    0x8(%rdi),%rcx
  14:	48 85 c0             	test   %rax,%rax
  17:	78 5a                	js     73 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x73>
  19:	48 89 cf             	mov    %rcx,%rdi
  1c:	49 bf ff ff ff ff ff 	movabs $0x7fffffffffffffff,%r15
  23:	ff ff 7f
  26:	48 89 c3             	mov    %rax,%rbx
  29:	4c 21 fb             	and    %r15,%rbx
  2c:	74 3a                	je     68 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x68>
  2e:	48 8d 34 9f          	lea    (%rdi,%rbx,4),%rsi
  32:	48 85 c0             	test   %rax,%rax
  35:	78 53                	js     8a <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x8a>
  37:	48 8d 14 99          	lea    (%rcx,%rbx,4),%rdx
  3b:	48 89 d9             	mov    %rbx,%rcx
  3e:	48 29 f2             	sub    %rsi,%rdx
  41:	74 0e                	je     51 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x51>
  43:	e8 00 00 00 00       	callq  48 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x48>
  48:	49 8b 06             	mov    (%r14),%rax
  4b:	48 89 c1             	mov    %rax,%rcx
  4e:	4c 21 f9             	and    %r15,%rcx
  51:	48 c1 e3 02          	shl    $0x2,%rbx
  55:	48 c1 fb 02          	sar    $0x2,%rbx
  59:	48 29 d9             	sub    %rbx,%rcx
  5c:	49 ff c7             	inc    %r15
  5f:	49 21 c7             	and    %rax,%r15
  62:	49 09 cf             	or     %rcx,%r15
  65:	4d 89 3e             	mov    %r15,(%r14)
  68:	48 83 c4 08          	add    $0x8,%rsp
  6c:	5b                   	pop    %rbx
  6d:	41 5e                	pop    %r14
  6f:	41 5f                	pop    %r15
  71:	5d                   	pop    %rbp
  72:	c3                   	retq
  73:	48 8b 39             	mov    (%rcx),%rdi
  76:	49 bf ff ff ff ff ff 	movabs $0x7fffffffffffffff,%r15
  7d:	ff ff 7f
  80:	48 89 c3             	mov    %rax,%rbx
  83:	4c 21 fb             	and    %r15,%rbx
  86:	75 a6                	jne    2e <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x2e>
  88:	eb de                	jmp    68 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x68>
  8a:	48 8b 09             	mov    (%rcx),%rcx
  8d:	48 8d 14 99          	lea    (%rcx,%rbx,4),%rdx
  91:	48 89 d9             	mov    %rbx,%rcx
  94:	48 29 f2             	sub    %rsi,%rdx
  97:	75 aa                	jne    43 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x43>
  99:	eb b6                	jmp    51 <clear(folly::small_vector<int, 5ul, void, void, void>&)+0x51>
```

after (much better but still 3 instructions too many):
```
0000000000000000 <clear(folly::small_vector<int, 5ul, void, void, void>&)>:
   0:	55                   	push   %rbp
   1:	48 89 e5             	mov    %rsp,%rbp
   4:	48 b8 00 00 00 00 00 	movabs $0x8000000000000000,%rax
   b:	00 00 80
   e:	48 21 07             	and    %rax,(%rdi)
  11:	5d                   	pop    %rbp
  12:	c3                   	retq
```

Reviewed By: ot, philippv, luciang

Differential Revision: D19890921

fbshipit-source-id: 62f1b5325b4deda95976894b476849b5098fad4f

Summary: This class is intended to be useful when part of your project is using folly logging and part is using glog - simply install this bridge up-front and everything is routed to folly logging.

Reviewed By: simpkins

Differential Revision: D19952822

fbshipit-source-id: 898846fc7b647ddd93222f46c56450c1454dc738

Summary:
Fix set SO_REUSEPORT error message, save errno, use throwSystemErrorExplicit

(Note: this ignores all push blocking failures!)

Reviewed By: vitaut

Differential Revision: D20052057

fbshipit-source-id: 2f1b3135ff84242aa7ad38d3063ef9e260c3127c

Summary: Use folly::sizedFree for the ext buffer

Reviewed By: yfeldblum

Differential Revision: D19934204

fbshipit-source-id: 63662ab547f15addc7cdb249704964dfc70ca1f3

Summary:
Instead of using a Linux-specific API for random numbers, use
std::minstd_rand. It's not precisely identical, but probably
sufficient for these tests.

Reviewed By: yfeldblum

Differential Revision: D20039048

fbshipit-source-id: 5ace1a0552f995a48b37e4fa2209394f1b28ca84

Summary: Fix signed/unsigned mismatch in json.cpp

Reviewed By: yfeldblum, jdonald

Differential Revision: D19671088

fbshipit-source-id: 4bc1f4111e0536aa22c7fd03a2a6a6d786b7cfc8

Summary:
The SAI diag shell implementation requires Python3.7.6.
Previous diff in the stack added Python3.7.6 manifest.
Make use of it to build diag shell and link with Python lib.

Differential Revision: D20064315

fbshipit-source-id: c855f8a9f554066e8150ce1d867828a84161961b

Summary:
As titled.

FBOSS depends on Python3.7.6, subsequent diff in the stack adds Python3.7.6
depedency for FBOSS.

Differential Revision: D20064316

fbshipit-source-id: 27b328dc25e326f3927ea6cb003fb7bb45732d61

Summary:
Add function `get_process_phase` that returns indicators of process phases:
- `ProcessPhase::Init`: Not all global variables may have been initialized.
- `ProcessPhase::Regular`: All globals have been initialized and have not been destroyed.
- `ProcessPhase::Exit`: Some globals may have been destroyed.

Add function `set_process_phases` and calls to it from `folly::init` and `common/init/Init.cpp` wherever `SingletonVault::singleton()->registrationComplete` is called.

Will add calls to `set_process_phases` in separate diffs to other places that call `registrationComplete ` directly.

See Section 6.9.3 Start and termination [basic.start] of the C++ Standard Working Draft [N4849](https://github.com/cplusplus/draft/releases/download/n4849/n4849.pdf).

In general this addition is useful for simplifying cases of dependence on the existence of certain globals during main, where it is safe to ignore such globals at shutdown.
For example, the destructor of `hazptr_obj_cohort` normally needs to access the default `hazptr_domain`, but it is safe to skip that access at shutdown.

Reviewed By: yfeldblum

Differential Revision: D19567170

fbshipit-source-id: a44cbd3301aa9dc77a1e992922403635a3ff6552

Summary: (Note: this ignores all push blocking failures!)

Reviewed By: farnz

Differential Revision: D19948740

fbshipit-source-id: 9d0cfc4ccbcb3c08bb969f23229ed3096470fa86

Summary:
Having the fallbacks in the public header files makes searching for classes/methods cumbersome, and some people have mistakenly assumed that F14 classes inherit from `unordered_*` because they landed on the wrong line.

In addition, when the fallback implementation is used, any compilation errors will come from the `*Fallback.h` files, making it clear that the main implementation is not being selected.

Reviewed By: yfeldblum

Differential Revision: D19926873

fbshipit-source-id: 492b0c252f33c0cbbf3c22dae38fa0bd63825f72

Summary: Capacity is known in almost all the modes (except when it's inferred from `malloc_usable_size`, which is probably something we should not do in the first place), so we can easily plug in sized deallocation.

Reviewed By: yfeldblum

Differential Revision: D19976657

fbshipit-source-id: cb03f7107195af614514645c88d12ac4999dea53

Summary:
rootid is the thing we use to correlate running Thrift requests with a folly::RequestContext. The problem is that today rootid is unique only for active requests but not unique throughout the lifetime of the process - as a consequence we see some subtle bugs like mistakenly attributing threads to already finished requests. The root cause of rootid collisions is that default implementation of rootid is just an address of folly::RequestContext - so once request finishes the address is reused.

The solution suggested here is to assign rootids explicitly when folly::RequestContext is set for the request. To construct such rootid we pack two counters:
* 12 MSB are dedicated to an ID of Cpp2Worker (should be more than enough)
* 51 LSB are dedicated to a running counter within Cpp2Worker.

(Note: this ignores all push blocking failures!)

Reviewed By: andriigrynenko

Differential Revision: D20036950

fbshipit-source-id: 76687db12a32f33c82ce86accb4cdaab3e981458

Summary:
generic API for setting socket options on a UDP socket

(Note: this ignores all push blocking failures!)

Reviewed By: yangchi

Differential Revision: D19763927

fbshipit-source-id: d1a7720b04c24592e98c6e30c93c26e650ccd0b0

Summary: delete the folly::AsyncSocket::OptionMap/OptionKey/emptyOptionMap aliases

Reviewed By: yangchi

Differential Revision: D19963346

fbshipit-source-id: 6beae0961a82d12efd4d784ec390031d9445cd2b

Summary: base diff to move AsyncSocket::OptionMap into SocketOptionMap. folly only changes and an alias for previous usages of AsyncSocket::OptionMap

Reviewed By: yangchi

Differential Revision: D19961899

fbshipit-source-id: fab060cc73409c77ea07ced663fbd0ee15a35be7

Summary:
We need to add a separate manifest for SAI 1.4 and build that too, but that is
for later diffs, for now, we need 1.5, so change it.

Differential Revision: D20019016

fbshipit-source-id: 8630340ac7c8b7d94e6b768a2efa96266b2cc3e0

Summary: Pull Request resolved: https://github.com/facebook/folly/pull/1319

Reviewed By: yfeldblum, lnicco

Differential Revision: D19951699

Pulled By: afrind

fbshipit-source-id: b71d96020ca486139472512726183ae4d3555b28

Summary: Use sdallocx for IOBuf::releaseStorage

Reviewed By: marksantaniello

Differential Revision: D19925485

fbshipit-source-id: 142276fb64e570e10bfd0b6e22d8c83b204d1c2b

Summary:
Add FOLLY_CLANG_DISABLE_WARNING for Unistd.h

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D19652177

fbshipit-source-id: 1fcc3bb65c3b0d73870e599f9fc0463c6836cf9b

Summary:
The Buck build of RocksDB supports LZ4, so if an Eden instance's
object cache ends up compressed with LZ4 compression, the opensource
getdeps build cannot open it. Enable LZ4 in the open source getdeps
build of rocksdb.

Reviewed By: pkaush

Differential Revision: D19961878

fbshipit-source-id: 9a4f37e12bd2b40a0c5dcf2dd1684876886fae26

Reviewed By: yfeldblum

Differential Revision: D19953637

fbshipit-source-id: c2135fc24084b7bba0c9d6fc978c8b6c8f9943d4

Differential Revision:
D19848850

Original commit changeset: 21e61529d8b9

fbshipit-source-id: c490eb0024a4cda830389a359ee2631615345f2d

Summary: Previously if the loop simply failed to execute the test could pass, add some minor changes to ensure control flow is as required.

Reviewed By: andriigrynenko

Differential Revision: D19960864

fbshipit-source-id: 5a437d9e7d3b7c249cbf999fe7ea5eecfe668658

Summary: Missing includes which break modular builds.

Reviewed By: igorsugak, luciang

Differential Revision: D19738860

fbshipit-source-id: 97a0329f3e558309ca87f4dd7be8dd96e9ba09a8

Summary:
If the waited upon object throws an exception when blockingWait is called within a fiber context this can cause a SIGABT as it is not permissible to yield (due to the inner baton) in an exception context.

To fix this, instead capture the exception and permit destruction to occur outside of exception handling.

Reviewed By: andriigrynenko

Differential Revision: D19951124

fbshipit-source-id: cf1bf9a62557147863390132f551d08e20c02c2d

Summary: It was originally disabled to let test pass in ovrsource, they are now passing, enabling them back

Reviewed By: pranjalssh

Differential Revision: D19848850

fbshipit-source-id: 21e61529d8b9f519b4c8cbf4787c8e3f28b99bb1

Summary:
Add folly::sizedFree

(Note: this ignores all push blocking failures!)

Reviewed By: ot

Differential Revision: D19944311

fbshipit-source-id: b5b1a648a180662fe838237c3c3b153e42fe0617

Summary: In C++20, u8 prefixed strings are typed as `char8_t` not `char`, so we need to support that in `StringPiece`.

Reviewed By: yfeldblum

Differential Revision: D19822967

fbshipit-source-id: c3441ba718b40f0781766d4a80c3432b4514a35c

Reviewed By: yfeldblum

Differential Revision: D19768449

fbshipit-source-id: b5a259486403601cf60d4e7066640e1ed4601410

Summary:
Currently the best way to get an eager SemiFuture from an AsyncGenerator is
  folly::coro::co_invoke(
      [&]()
          -> folly::coro::Task<folly::coro::AsyncGenerator<T&&>::NextResult> {
        co_return co_await gen.next();
      })
      .scheduleOn(&ex)
      .start();
which is very verbose. This diff adds helpers to make this a simple function call.

Reviewed By: andriigrynenko

Differential Revision: D19835473

fbshipit-source-id: f6e7e72cad0e0596df375d2662c87d4412536c03