Summary:
We currently leak ptr entries due to a missing map erase call in AsyncSocket::releaseZeroCopyBuf.
Also addZeroCopyBuf called when the bytesWritten == 0 will cause and extra id to be allocated. This will delay the deletion of the last IOBuf sent via zerocopy. The number of buffers can accumulate over time if the same bytesWritten == 0 situation is encountered.
Found when running the nbd-server zero downtime upgrade during heavy fio traffic.
Add an AsyncSocket::processZeroCopyWriteInProgress so we can drain the zerocopy msg error queue even after we set the ReadCallback to nullptr.

Reviewed By: djwatson

Differential Revision: D6552982

fbshipit-source-id: 3d2fdca84ec3b5fc46c3bed06c0c9ede66ed565a

Summary: When I was investigating the difference between glog/xlog I encountered this.

Reviewed By: yfeldblum

Differential Revision: D6572117

fbshipit-source-id: 4130deb6cfed7cfb7d2433cdab292481beb2469f

Summary: [Folly] Use explicit memory order in `Baton::post`.

Reviewed By: djwatson

Differential Revision: D6502268

fbshipit-source-id: a379ea711f165e3645ac2127a49824f46225b80a

Summary: They belong here rather than AsyncTransportWrapper.

Reviewed By: siyengar

Differential Revision: D6568209

fbshipit-source-id: 0856dba0b2d527ae68d33942b28e2c485a5b1f46

Summary:
DynamicBoundedQueue supports:
- Dynamic memory usage that grows and shrink in proportion to the number of elements in the queue.
- Adjustable capacity that helps throttle pathological cases of producer-consumer imbalance that may lead to excessive memory usage.
- The adjustable capacity can also help prevent deadlock by allowing users to temporarily increase capacity substantially to guarantee accommodating producer requests that cannot wait.
- SPSC, SPMC, MPSC, MPMC variants.
- Blocking and spinning-only variants.
- Inter-operable non-waiting, timed until, timed for, and waiting variants of producer and consumer operations.
- Optional variable element weights.

Reviewed By: djwatson

Differential Revision: D6462123

fbshipit-source-id: 5c7a7d88c3fa273211702af9ff78f6302afd2276

Summary: Use alignas instead of FOLLY_ALIGNED

Reviewed By: Orvid

Differential Revision: D6554984

fbshipit-source-id: 5b11ac387faa137aa8dd0c35b6e9bb999cf0bf2d

Summary:
[Folly] Fix `AsyncSocketTest.WriteErrorCallbackBytesWritten`.

Thanks to congestion, especially when the tests are run concurrently, the expectations in the test were too restrictive.

If only 20KB are read, it is possible that only 20KB are acknowledged. The expectation was that if 20KB are read and the recv buffer and send buffer are both 8KB and 24KB are written then all 24KB are acknowledged, but congestion control disagrees.

It is possible that any number of bytes are written to the send buffer, from 28KB up to 40KB. And we have to explicitly wait for 28KB to be written even to know that (otherwise we only know that 20KB are written).

Differential Revision: D6550804

fbshipit-source-id: 100d086972c1526b909da0dbb6e609c144d7b17b

Summary: [Folly] `constexpr_ceil`, an integral rounding-up util.

Reviewed By: Orvid

Differential Revision: D6558042

fbshipit-source-id: 6b42add9bf2e3605baf71391130c2a2c88cc4385

Summary:
[Folly] Move `max_align_v` and `max_align_t` to `folly/lang/Align.h`.

And drop the macro `FOLLY_ALIGNED_MAX` - just use `alignas(max_align_v)` instead.

Reviewed By: Orvid

Differential Revision: D6554677

fbshipit-source-id: cacb335b141623506a41e95e0740613374279c6f

Summary: [Folly] Remove unused `#include <string.h>` from `folly/Portability.h`.

Reviewed By: Orvid

Differential Revision: D6557374

fbshipit-source-id: 369ef0b622dc057e882ed0f4ad25b47fa3f05100

Summary:
This is a hard requirement due to an upcoming change in Folly.

The codemod was only run on files that referenced the `std::chrono` namespace with an unqualified `chrono` and also used both the `std` and `folly` namespaces.
```
fbgr -sl "[^:]chrono::" | xargs grep -l "using namespace std;" | xargs grep -l "using namespace folly;" | xargs sed -r -i 's/([^:])chrono::([a-z])/\1std::chrono::\2/g'
```

Reviewed By: yfeldblum

Differential Revision: D6547864

fbshipit-source-id: 4a8230d311edbaa173722a09b2773e8d053fae7e

Summary: Closes https://github.com/facebook/folly/pull/721

Differential Revision: D6558163

Pulled By: yfeldblum

fbshipit-source-id: ed03aa92b54c61f9980a4759da29910aa77d5db6

Summary: This adds an RCU implementation, matching http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0461r1.pdf as closely as pratical.  This implementation does not require thread registration or quiescence.

Reviewed By: magedm

Differential Revision: D6330631

fbshipit-source-id: 2c729f3a4c0f151cde5d9a599ecd2a2c20c7da55

Summary:
Update the comment describing the Logger class, and remove a `clang-format off`
since recent versions of `clang-format` appear to do a good job formatting this
macro.

Reviewed By: yfeldblum

Differential Revision: D6525996

fbshipit-source-id: 6abbb3740afb53feb2418ca890cd78af1eb5f7a2

Summary: Add several new documents describing the behavior of the folly logging library.

Reviewed By: yfeldblum

Differential Revision: D6525997

fbshipit-source-id: 8ba2ff99c70c7566987b3da321526a16755e72bf

Summary: Switch to the `try_wait_for` and `try_wait_until` `Baton` APIs.

Reviewed By: davidtgoldblatt

Differential Revision: D6532103

fbshipit-source-id: aa3ce64152d167bb9c9cb1f266be0f9f8bd498f5

Summary:
It looks like not having offset/size/filename information is way more
harmful, than storing filename just for the sake of this error message.

Reviewed By: yfeldblum

Differential Revision: D6536616

fbshipit-source-id: 469fbdf1deedd76ebd79cf98716c2c269cb10e4d

Summary:
[Folly] Assorted tweaks to `folly/String.h`.

* Use `void_t` in the definition of `IsConvertible`.
* Remove `AllConvertible`. Callers can use `StrictConjunction` instead.
* Move the `static_assert`s from the header to the source file.

Reviewed By: andrewjcg, ot

Differential Revision: D6501515

fbshipit-source-id: 472ecf23bf7f06be211480b0aceea95f7e60dc21

Summary: In some cases, SSLContextManager seg faults if a cert and key do not match.  This guards against that case when strictSSL = false, and throws a more useful error in the cases when SSL is required.

Reviewed By: xybu

Differential Revision: D6513964

fbshipit-source-id: 8e63a22b346fd3f2a30d558a3659ab6794c7a105

Summary:
[Folly] `folly::fibers::Baton` API consistency with `folly::Baton`.

Specifically, the suite of `wait`, `try_wait`, `try_wait_for`, and `try_wait_until` members and member templates.

Hold onto the `timed_wait` members for now, but mark them deprecated.

Additionally, for consistency, offer main-context function params consistently for all `try_wait_for`, `try_wait_until`, and both variants of `timed_wait`.

Reviewed By: andriigrynenko

Differential Revision: D6531145

fbshipit-source-id: 960fba48716b12b0ef53262786eacab88d8b2375

Summary:
Content size 0 as unknown is deprecated.
See code comments for details.

Reviewed By: felixhandte

Differential Revision: D6521582

fbshipit-source-id: 876b94cc0123c1020b456cc8f4cd86997afe0619

Summary:
[Folly] Remove multi-poster support from `Baton`.

Code which needs multi-poster support may use `SaturatingSemaphore` instead.

Reviewed By: magedm

Differential Revision: D6529661

fbshipit-source-id: d9dc053ca984ef3a404e9361910b0044817d4905

Reviewed By: Orvid

Differential Revision: D6387412

fbshipit-source-id: 4c1424ed4fa49e69885de8cd72e78169314fc502

Summary: Remove include not needed after recent change

Reviewed By: yfeldblum

Differential Revision: D6529608

fbshipit-source-id: 904072084e180125d68bd1ef6e4dffb2939cd1eb

Summary:
[Folly] Fix signed integer overflow in `StaticTracepointTest.cpp`.

It is undefined behavior and is caught by UBSAN in some test runs.

Reviewed By: Orvid

Differential Revision: D6528445

fbshipit-source-id: e4a199e9005b57bcd93c8c4b69f37ccb1e072bdf

Summary:
[Folly] Split `Baton` wait methods into fast and slow paths.

Force-inline the fast paths, and force-outline the slow paths.

Reviewed By: magedm

Differential Revision: D6501992

fbshipit-source-id: 611e26b3cfeef01eb8d3a3500ae3ebc26bee6e86

Summary:
[Folly] Fix UBSAN failure in `RangeTest.cpp` with `libstdc++-v4.9`.

The implementation of `std::array` in `libstdc++-v4.9` has undefined behavior in the case of the zero-length array - dereferencing (but immediately taking the address again) of `nullptr`. This is fixed in `libstdc++-v5`.

Reviewed By: ot

Differential Revision: D6528614

fbshipit-source-id: 26be6bdc28d9e6dc6e6293a4d4ecffd769c01413

Summary: As above. Thanks magedm for giving us this beautiful piece of equipment!

Reviewed By: magedm

Differential Revision: D6488661

fbshipit-source-id: 95aa9646ca1ea937bb1d055e9baa037896c3161e

Summary:
- Add a template parameter, LgAlign, to control memory usage. The parameter is used in DynamicBoundedQueue.
- Refactor code.

Reviewed By: yfeldblum

Differential Revision: D6508015

fbshipit-source-id: 6e17b1d8fd900595147dc4217e04d379a13fbdf8

Summary: [Folly] Move `folly/Bits.h` to `folly/lang/`.

Reviewed By: phoad, Orvid

Differential Revision: D6495547

fbshipit-source-id: a93159321df8277f8a4b4f10a5e4e0fc58cb6022

Summary: If the folly::Function returns by const& and the wrapped function returns a prvalue, it is guaranteed to return a dangling reference. Prevent it.

Reviewed By: yfeldblum, aary

Differential Revision: D6487447

fbshipit-source-id: 61700b4688e29409eefa27f546b31ecac258cfdd

Summary:
Update string literals with escaped quotes and backslashes to use raw string
literal syntax instead.

Reviewed By: yfeldblum

Differential Revision: D6501426

fbshipit-source-id: 557366f86b360596b13148d03fd33c7df5c3f890

Summary: Use SaturatingSemaphore instead of multi-poster and non-blocking Baton, in preparation for restoring Baton to being single-poster and with blocking wait().

Reviewed By: davidtgoldblatt

Differential Revision: D6510619

fbshipit-source-id: eed87beabc1b698080b8e41c746d570d30804ce7

Summary:
[Folly] Fix crash in `exception_wrapper::get_exception<>`.

When the contained object is unthrown and does not inherit `std::exception`, `get_exception` templated over a type that does not inherit `std::exception` must throw and catch internally and may then return a pointer to the internally thrown object, which has since been deallocated.

Attempting to dereference that pointer is undefined behavior is correctly caught by ASAN as heap-use-after-free.

Fix it by storing objects not inheriting `std::exception` using only the `std::exception_ptr` representation.

As a downside, we no longer get the small-object optimization or the non-throwing optimization for objects which do not inherit `std::exception`. But this is not likely to be terribly concerning in practice.

Reviewed By: ericniebler

Differential Revision: D6504911

fbshipit-source-id: 0065de911733b5cab87be55e7e4e47f0a9c09140

Summary:
[Folly] Use simpler tags for ctor dispatch in `exception_wrapper`.

The tags do not need to be `std::integral_constant`, but can just be arbitrary empty types.

Also format the usage sites of the tags.

Reviewed By: ericniebler

Differential Revision: D6506417

fbshipit-source-id: 377359086d94fc1a8bf8eebf6f8b058ff544829f

Summary: glog actually tries to pull srtings from these pointers when the checks fail, which obfuscates the error

Reviewed By: yfeldblum

Differential Revision: D6506886

fbshipit-source-id: 0283e02aecaa248b84fca1433d3f29f92c37b2e6

Summary: deadcode

Reviewed By: ddrcoder

Differential Revision: D6498754

fbshipit-source-id: 9dda0ade6928d648b8938a06b185e430753f2318

Reviewed By: yfeldblum

Differential Revision: D6503762

fbshipit-source-id: f82b88c401979761053004eadd2e4c6a74f05f9c

Summary:
This updates the LogHandlerConfig code to allow changing the settings on an
existing log handler without listing all of its existing options from scratch.

This also changes the syntax of the basic log handler configuration string to
use a colon to separate the log handler name+type from the options list.  In
other words, rather than specifying `default=stream,stream=stderr,async=true`
you now say `default=stream:stream=stderr,async=true`.

The primary motivation for this change is to make it easy for users to switch
the async setting for the default log handler on or off.  Callers can now
specify `default:async=true` to easily enable async mode on the default log
handler without having to completely re-list the full settings for the default
handler.

Reviewed By: yfeldblum

Differential Revision: D6494228

fbshipit-source-id: 52a296f800a5456f0c3aa10546298139c8db52fc

Summary:
Split FileHandlerFactory into separate FileHandlerFactory and
StreamHandlerFactory classes, where FileHandlerFactory only handles logging to
files by path name, and StreamHandlerFactory only supports logging to stdout or
stderr.

The primary motivation for this is to allow logging to stdout or stderr in some
cases without allowing arbitrary files to be opened by FileHandlerFactory.
This can be achieved now by registering StreamHandlerFactory but not
FileHandlerFactory.  This makes it safer to allow controlling logging
configuration via command line flags even in setuid binaries.

Reviewed By: yfeldblum

Differential Revision: D6494226

fbshipit-source-id: a3ec371ca4266424d07dff20be18e6e13c057593