Summary: Since this API is discouraged from use, users should call `folly::observer_detail::ObserverManager::waitForAllUpdates` (and face whatever consequences may come with it).

Reviewed By: yfeldblum

Differential Revision: D25629064

fbshipit-source-id: 141b27bbc4f7cf9b628f15f837c38dd4d8a04f31

Reviewed By: zertosh

Differential Revision: D25662961

fbshipit-source-id: f5811a5797fd6dc8733fdf86f35c93d12a08d53a

Summary: Fix `Arena` total-size accounting across calls to `clear`, as reported by member `totalSize`.

Reviewed By: luciang

Differential Revision: D25656867

fbshipit-source-id: b5c7bb0e95199a9fa2c94c04de65b8f494eef146

Summary: Don't use gtest/gtest.h directly.

Reviewed By: yfeldblum

Differential Revision: D25659806

fbshipit-source-id: a8dd0da814465a787ab7904bdd0256f22b6e3ed8

Summary: As per title

Reviewed By: yfeldblum

Differential Revision: D25636982

fbshipit-source-id: a59c2325558175e122941000ab645c8735a3a425

Summary: Use `throw_exception` consistently in `Arena` for consistency.

Differential Revision: D25637401

fbshipit-source-id: 92cda5acc09b871fed78044fa3f3fa2c41b01609

Summary: [folly] `asan_region_is_poisoned` to wrap Address Sanitizer's `__asan_region_is_poisoned`.

Reviewed By: ot, luciang, markisaa

Differential Revision: D25651040

fbshipit-source-id: 0c8f1d0203ada43746b5e2e71c1bd8b883248f68

Summary: All changes were automated

Reviewed By: Orvid

Differential Revision: D25507555

fbshipit-source-id: c0be9a04b8a5f502f4753ce6e163a78c428bfad6

Summary:
Fix QUIC OSS build

(Note: this ignores all push blocking failures!)

Reviewed By: danobi

Differential Revision: D25645282

fbshipit-source-id: fcb71d4e930d7ac3802f31d71599338fb346eb80

Summary: Required for Windows with the more strict include order via upcoming formatting diffs.

Reviewed By: yfeldblum

Differential Revision: D25636437

fbshipit-source-id: 0a5fd400f63220400f89affb11b66e9692e9b352

Summary: Because folly can't depend on common.

Reviewed By: yfeldblum

Differential Revision: D25636772

fbshipit-source-id: d7b049330c9ca68eb4013fde5ca6de9413433823

Summary: Allow scheduling a "poison" task to indicate shutdown

Reviewed By: andriigrynenko

Differential Revision: D25609015

fbshipit-source-id: 8a42b99b402d78db7cfa3bd194730bb6948567c6

Summary: Currently doesn't do anything since TLS 1.3 is not yet enabled by default. Once it is, calling disableTLS13() on a context will set the max TLS version to TLS 1.2.

Reviewed By: mingtaoy

Differential Revision: D25642589

fbshipit-source-id: 0e580916b929111ed9721ca142b59eab0ea187df

Summary: Allows use with std::optional when available

Reviewed By: WillerZ

Differential Revision: D25618828

fbshipit-source-id: 3e039406ff1e885fd1767148b907635b23f7a88b

Summary: Use comparison expectations like `EXPECT_GE` in `Arena` test as v.s. `EXPECT_TRUE` with the comparison inside.

Reviewed By: markisaa

Differential Revision: D25631097

fbshipit-source-id: 4fb430f34d7683e3b82dd3fbb4408360f8990353

Summary: All changes were automated

Reviewed By: Orvid

Differential Revision: D25507575

fbshipit-source-id: cbddef5a79008d9bf8b6e0234e6433084e5d8df9

Summary: These are the only files out of hundreds in folly that have them, so just remove them entirely.

Reviewed By: yfeldblum

Differential Revision: D25612198

fbshipit-source-id: 88d4f5c2ffa08d45d0a901c9ef874cddc2730291

Summary: Eliminate noisy log message and provide the intended deadlock clue in a function name.

Reviewed By: yfeldblum

Differential Revision: D25627130

fbshipit-source-id: 8d92007d4fa7eff1efb5857f7f49bebde2d59b70

Summary: Specifically, ending in Test, singular, and reflecting the file being tested in full.

Reviewed By: yfeldblum

Differential Revision: D25612187

fbshipit-source-id: 514477e08b9e231d8574cae19640717b689b7d56

Differential Revision:
D25549986 (https://github.com/facebook/folly/commit/9a83e4242a933f91c9339b4c6d223267a43a89c1)

Original commit changeset: fd323e2e8cbf

fbshipit-source-id: af2bdb9f66d23d144f7e2e96118727d8b158f83f

Summary:
folly::AsyncSocket: propagate finishFail ex

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D25479314

fbshipit-source-id: 683e1e118ace2ea983bde78d8afddb84dab69f6f

Summary:
AsyncUDPSocket: multi release pacing for UDP GSO

(Note: this ignores all push blocking failures!)

Reviewed By: mjoras

Differential Revision: D25451694

fbshipit-source-id: 3550a3744b407cbc40efebe759f472ee9f40a5b8

Summary:
The `StringPiece` overloads of comparisons operators are inefficient to compile, as they get in the overload set of every comparison and then get ruled out by SFINAE (which require trait instantiations).

Move them instead to friend inlines, where they enjoy the expected implicit conversion rules.

(Note: this ignores all push blocking failures!)

Reviewed By: yfeldblum

Differential Revision: D25549986

fbshipit-source-id: fd323e2e8cbf4f3dd29508b8aff1cfaba2784f4f

Summary:
Previously theFOLLY_HAVE_LIBUNWIND macro would evaluate to false even if LibUnwind was available.

Pull Request resolved: https://github.com/facebook/folly/pull/1501

Reviewed By: yfeldblum

Differential Revision: D25583562

Pulled By: Orvid

fbshipit-source-id: 7dac5afa1f0f24747f4accf2e08b804ab12e416f

Summary:
Motivation: we sometimes need to add concept of lower priorities on top of executors which provide custom scheduling via custom APIs such `EDFThreadPoolExecutor`.

This adapter wraps an arbitrary executor, and adds an additional queue. Tasks from this queue will be fetched and placed on the wrapped executor's queue in a metered fashion - in particular we only allow up to "maxReadAtOnce" tasks to be placed onto the main executors queue.

Once work is added to metered queue, the adapter schedules callback into the wrapped executor. When callback is executed it:
1) fetches head task from the queue
2) fetches up to maxReadAtOnce - 1, and reschedules those onto the main executor.
3) reschedules itself onto the main executor
4) executes the task fetched at stage 1.

While in theory this algorithm does not provide strong priority guarantees, in practice lower priority tasks are almost always yielding to the higher priority tasks.

This primitive also allows interesting compositions to be built:
1. multiple priorities scheduling can be achieved by chaining metered adapters.
2. Fair queue scheduling (e.g. round robin consumption from N queues) can be achieved by creating N metered adapters wrapping the same executor.

(Note: this ignores all push blocking failures!)

Reviewed By: prshreshtha

Differential Revision: D24983861

fbshipit-source-id: 1a4ce61fc7cc706889da9724de71822bfaab440b

Summary:
So it may be easier to use in Python code.

A lot of Python code will check the type with this:
```
if isinstance(obj, (bytes, memoryview)):
  ...
```

Currently, the `IOBuf.__iter__` returns a `cython.view.memoryview` c-type (which can be only "cimport" in cython but not able to "import), and to make it useable in scenarios like above, we have to explicitly cast it to builtin `memoryview`.

With this change, the use of the iterator is more natural.

Reviewed By: fried

Differential Revision: D25577842

fbshipit-source-id: 6b22028d06bba639fca32f7de3a063e1fb1baa15

Summary:
Benchmarks are great, but are missing parts that allows them to be run outside of raw binary, like in mobile context, where we generally want to showcase the list of results, instead of pretty printing them to stdout.
To allow for that - adding a new public API, and restructuring few things, to code dedupe and still maintain the same functionality.

Reviewed By: Orvid

Differential Revision: D25552087

fbshipit-source-id: 946a9fbcac3faff0a69f3d86d20f3621649c7e5a

Summary:
This new API has a few benefits:
1. It allows `getSSLSession` to support TLS 1.3 session resumption by returning a mutable session wrapper as opposed to the immutable `SSL_SESSION*` object.
2. OpenSSL `SSL_SESSION*` objects require the caller to keep accurate reference counts. Failure to do so can result in memory leaks or use-after-free errors.
3. This design abstracts away OpenSSL internals, which are unnecessary for the caller to perform session resumption.

Reviewed By: mingtaoy

Differential Revision: D24239802

fbshipit-source-id: cd3e90217717394f32dc6a2281e7a40c805990b2

Summary:
In most cases, `folly::observer::waitForAllUpdates` should not be needed. However, the asynchronous nature of observers break some basic assumptions that most users expect. Such as:
```
thing.set(value);
EXPECT_EQ(thing.get(), value);
```
If `thing` is using `folly::observer` underneath the hood, the asynchrony is passed on to the user which is very easy to overlook, leading to bugs. The API of `thing` might want to enforce that when `thing.set` returns, all observed values will have been updated.
Blocking is a perfectly okay solution in cases we don't expect an observer to be updated frequently.

Differential Revision: D25542376

fbshipit-source-id: c83909807fbf36e0311a45b667da94c43751a1da

Summary: Mirrors Task. One behavioral difference is that yielding an empty Try from a Task converts into a UsingUninitializedTry exception, while for AsyncGenerator it converts into a return. This is for consistency with Thrift's ClientBufferedStream to avoid confusing users, but there is also an argument for converting to UsingUninitializedTry instead.

Reviewed By: yfeldblum

Differential Revision: D25379361

fbshipit-source-id: 2a2878185696566b29345c99fee7ba74bef4ae8a

Summary:
This diff introduces a generic abstraction to convert a python error (set by a C-API call) into an informative C++ exception.

The main motivation for this is to improve the error handling behavior when dealing with failed cython api module imports.

This diff adds one callsite to the new abstraction in fiber.cpp  to demonstrate its usage.

Reviewed By: yfeldblum

Differential Revision: D25469594

fbshipit-source-id: e9f83c06460f35fa76030ceae9726297276db850

Summary:
When SingleProducer is disabled, AsyncPipe's method becomes thread-safe
and can be called by multiple threads simultaneously. This is useful
in a use case where a long running operation is being executed by
multiple threads that all want to post status updates to the same
AsyncPipe instance.

Reviewed By: iahs

Differential Revision: D25494695

fbshipit-source-id: 1d0a74ec69dc8f64c171e21be612d211919cda4b

Summary: All changes were automated

Reviewed By: Orvid

Differential Revision: D25507592

fbshipit-source-id: 3ce36732a2d1c691087fbd95c3e87f554f4d8d98

Summary:
During tsan test, sometimes annotationGuard() is called after kAnnotationMutexes is already destroyed which throws exception.
This change fix the issue by uses Indestructible for kAnnotationMutexes, so that it is not destroyed.

Reviewed By: yfeldblum

Differential Revision: D25443571

fbshipit-source-id: 69411a7edc4f96ba8c7d08bd29f87ab7b2ff78ae

Summary:
This includes several enhancements to folly::small_vector:

Eliminate overhead accessing vector elements by making heap_ points to element 0 of the vector.  To get start address only dispatch is required as shown below:

     value_type* data () {
       // Dispatch between heap_ or internalStorage,
       return isExtern() ? heap_ : &internalStorage_;
     }

Reorganize the implementation by recording if capacity is stored internally or on the heap in "size". As a result the maximum vector size is half smaller. This is the only visible behavior change of this PR. Assuming size is 64 bits then
  - bit63 determines if vector elements are stored in internalStorage_ or externally in the heap
  - bit62 determines if vector capacity is stored internally or on the heap
  - bit61..bit0 contain the size of the vector.

Reduce the overhead of updating size buy adding incrementSize functions.

Tune emplace_back function and vector initialization.

Reviewed By: yfeldblum

Differential Revision: D24413105

fbshipit-source-id: b447704832af9c734be51aa6d23b8cb4be69a8bf

Summary:
The initialization of `folly::MicroLock` *looks* correct. MSAN instrumentation probably needs to be disabled in its implementation.

Regardless, the main point of using `folly::MicroLock` was its low memory usage (1 byte). I'm now changing it to `folly::SharedMutex` (4 bytes) which will be the same size due to alignment. Although `folly::SharedMutex` is not ideal for write-only locks, we don't care too much about write performance here.

Differential Revision: D25487925

fbshipit-source-id: 4c30650cf22dafbdaa9fea0c2252d29caf477d54

Summary: folly/Traits.h defines a `void_t` alias in the `folly::` namespace. Just use that instead of specifying the one in `std::`.

Reviewed By: ispeters

Differential Revision: D25483712

fbshipit-source-id: 6be0435dfec600690cc90bc15fd3d2af17826173

Reviewed By: prshreshtha

Differential Revision: D25387330

fbshipit-source-id: 027e04024e01d1eab938d67a2d1dfc93c9322b15

Summary: The call-once logic in getFiberManager was unnecessarily complex. getFiberManager should only be called on main context, so use a static var initialization to implement the call-once logic (using executor.cpp as an example).

Reviewed By: yfeldblum

Differential Revision: D25467655

fbshipit-source-id: c880b1740edf28944e772c9310f3e45f5612396d

Summary:
With the current constructor setup, overwriting multiple request datas involves chaining together multiple ShallowCopyScopeGuard. This is quite inefficient as it involves copying the requests-data/callbacks maps multiple times.

This diff introduces a new variadic constructor that accepts RequestDataItems (named pair of token and data)

Reviewed By: A5he

Differential Revision: D25317291

fbshipit-source-id: 8a9cb00a615ecf802f22727189e4dc5a0c056c73