Summary:
Problem:
- `IP_RECVERR` symbol is not defined on Mac OS.
- A test expects this symbol to be found. But, in the case on Mac OS, the symbol is not found and hence will cause a hard compiler error.

Solution:
- `ifdef` the portion of the test that is relying on this symbol.
Pull Request resolved: https://github.com/facebook/folly/pull/899

Differential Revision: D9140373

Pulled By: yfeldblum

fbshipit-source-id: 127ab352cea790194171376ac809c23249883251

Summary: This is a unittest for an issue I fixed previously (but had to land ASAP).

Reviewed By: yfeldblum

Differential Revision: D9140622

fbshipit-source-id: 09dcb4206d2a09a57c2f2239a1aa217b124e88fd

Summary: Some of the RequestData's instances share same thread-local, and rely on strict ordering of unset/set

Reviewed By: djwatson

Differential Revision: D9138483

fbshipit-source-id: fba59a7f5619d54ed21d71a40fb2cc6ce0e93797

Summary: Disable GSO if FOLLY_HAVE_MSG_ERRQUEUE is not defined

Reviewed By: yfeldblum

Differential Revision: D9128837

fbshipit-source-id: 25977eb7f46ac57dca17c7956277f9f647357baa

Summary:
This diff allows `folly::dynamic` to lookup and mutate using any type that is
convertible to `StringPiece` (i.e., `const char*`, `std::string`, `fbstring`)
without having to construct a `dynamic` object (which requires copying the
string).

Currently dynamic string types uses fnv32 hash, which is OK since F14 is going
to do a mixing step anyway; we are changing this in D8304491.

Reviewed By: yfeldblum

Differential Revision: D8299863

fbshipit-source-id: a154bfe8f17e1d83968cdc1755ec54b6eed4299e

Summary:
F14NodeMap is a safe drop-in replacement for std::unordered_map. It is smaller
than std::unordered_map (32 bytes instead of 56 bytes) and has been shown
to be faster in many production use cases. This diff replaces the hash table
inside folly::dynamic. The effect is that sizeof(folly::dynamic) will drop from 64
bytes to 40 bytes, and use cases that use folly::dynamic as an object may also
get a CPU win.

Reviewed By: nbronson

Differential Revision: D8299800

fbshipit-source-id: abd0b034537c95f2ccbdf78fe5ae8fe9157f32ac

Summary:
In my use case, at least, it's very likely that most Fibers are sharing the same RequestContext.
This could save a lot of onSet/onUnset calls.
Unsafe?

Reviewed By: andriigrynenko

Differential Revision: D9115679

fbshipit-source-id: 216208dff509c61b9f20f324c3e648ec79ebbaf7

Summary: Public method to get `maxSize` for `TDigest`.

Reviewed By: yfeldblum

Differential Revision: D9124932

fbshipit-source-id: 1effab8900c3007f6a92d9d6c1d83189746f4ac6

Summary:
There is no reason for setContext to call set/unset when both request context holds identical data.
So merge unsetShallowCopyContext implementation there.

Reviewed By: djwatson

Differential Revision: D9119718

fbshipit-source-id: 7b9c6badbfb29416b6b0032467984720b697a1e8

Summary:
This is to be consistent with setContext, which doesn't call set/unset of the default context.
Main goal is to merge code in next diff.

I think the default context is never relevant, and should only be the current context in the internal of the async framework, in between executing coroutines.
We should probably enforce that request data is never set in the default context to guarantee correctness.

Reviewed By: djwatson

Differential Revision: D9119717

fbshipit-source-id: 8fa07520d506c02663f58f7616f1f390645997bc

Summary: Mishandling of parent end boundary.

Reviewed By: djwatson

Differential Revision: D9119716

fbshipit-source-id: c186e5acffdedc77577e1ab3a7b5876a6423e0f4

Summary:
- Replace uses of `boost::next` with `std::next`.
- Replace uses of `boost::prior` with `std::prev`.
Pull Request resolved: https://github.com/facebook/folly/pull/896

Reviewed By: ot

Differential Revision: D9114372

Pulled By: yfeldblum

fbshipit-source-id: 4b15b81ffb43dee00b64c4abc171747a95ceb6b7

Summary:
We have seen some caller-confusion after removing the lvalue-qualified Future::get().

Goal of this is to improve/clarify the compile-time error-msg for `future.get()`.

The resulting error-messages are compiler-dependent, but generally they are more explicit, indicating an explicit deletion of the lvalue-qualified method, and in some cases also displaying the deprecation-message:

* Clang:
  * old: 'this' argument to member function 'get' is an lvalue, but function has rvalue ref-qualifier
  * new: call to deleted member function 'get': must be rvalue-qualified, e.g., std::move(future).get()
* gcc:
  * old: error: passing 'Future<int>' as 'this' argument discards qualifiers [-fpermissive]
  * new: use of deleted function 'T Future<T>::get() & [with T = int]'
* MS VC:
  * old: 'int Future<int>::get(void) &&': cannot convert 'this' pointer from 'Future<int>' to 'Future<int> &&'
  * new: 'int Future<int>::get(void) &': attempting to reference a deleted function
* icc:
  * old: function "Future<T>::get [with T=int]" (declared at line 6) cannot be called on an lvalue
  * new: function "Future<T>::get() & [with T=int]" (declared at line 9) was declared deprecated ("must be rvalue-qualified, e.g., std::move(future).get()")

Reviewed By: yfeldblum

Differential Revision: D9071064

fbshipit-source-id: a40712ce94fd10bc153cb74a7d6d6a0539e07a15

Summary: [Folly] Use C++ v.s. PP to handle libcpp in `dynamic` ctor taking `std::vector<bool>::const_reference`.

Reviewed By: shixiao

Differential Revision: D9027115

fbshipit-source-id: 94de4260d1d40ac450c37d3803994d436adcf06e

Summary:
[Folly] Mark `std::list` as not relocatable.

From the github issue (facebook/folly#889), `std::list` allocated storage may hold back-pointers to the owning `std::list` object in both libstdc++ and libc++.

The relocatability marking dates to 2011 or earlier; perhaps it applied then.

Closes #889.

Reviewed By: nbronson

Differential Revision: D9043357

fbshipit-source-id: bf954e74f36f554bfbb2e5bb5ac40b933a749003

Summary: Fix a few nits in the contracts/specification

Reviewed By: yfeldblum

Differential Revision: D8962060

fbshipit-source-id: 8344403d3e26a01bef02deee3bb964fbaf6a1591

Summary:
This is the implementation of the unbounded concurrent priority queue based on Mound.
 - The data structure supports push, pop, size and empty operations.  [TODO: timed pop]
 - User can select whether it is the strict priority queue (PopBatch = 0), or relaxed implementation (PopBatch > 0).
 - Supports blocking.

Reviewed By: magedm

Differential Revision: D9028417

fbshipit-source-id: e12dc43aef4fb5b1195d9e27807cbd9f0ad1a401

Summary:
[Folly] Use brace-initialization for `folly::none`.

Will help with future work.

Reviewed By: shixiao

Differential Revision: D9039671

fbshipit-source-id: fc34041bc040332540ed3e9dfd7ab452e82ca47f

Summary: Adding UDP generic segmentation offload support

Reviewed By: siyengar

Differential Revision: D8825396

fbshipit-source-id: 5974307c2a901f4967e6f1c678b604ec1c21b3d0

Summary: Removes support for thenTry to accept a lambda with no parameter list and fail to compile with no arguments.

Reviewed By: yfeldblum

Differential Revision: D9011934

fbshipit-source-id: ec29b0c3d9475e7d2c566469b0ee333f0dc05738

Differential Revision:
D8875766

Original commit changeset: d88a323e6c14

fbshipit-source-id: 0f250135c084780895c99e47509e9d41cec0b88f

Summary: `strerror` isn't thread safe, `folly::errnoStr` is.

Reviewed By: yfeldblum

Differential Revision: D9036249

fbshipit-source-id: da4ad1089f4319e62b0273ec12b4950624105a77

Summary:
[Folly] Fix `fbvector::swap` impl to do proper ADL.

Instead of passing template parameters, cast the arguments. That way non-template `swap` overloads can also be found.

Reviewed By: Gownta

Differential Revision: D9026136

fbshipit-source-id: 29240fed1c90d3556c2476917a21cbe1949c9a3c

Summary: Added option to send parameters to 'configure' script from fbcode builder

Reviewed By: jstrizich

Differential Revision: D9004547

fbshipit-source-id: da54fa2dd453aab29051f37106423807a260535a

Summary:
[Folly] Tweaks to Futures after {D9015012}.

* Publish base-class methods with `using`.
* Use trailing-comma in list initializers.

Reviewed By: shixiao

Differential Revision: D9024885

fbshipit-source-id: d1e548630152a7d7ce892084daef24a4e62dd0df

Summary:
The futures created by FutureSplitter don't carry the orginal future's
executor priority, what makes it hard to guarantee that certain operations
based on a future chain run on a determined executor priority.

Reviewed By: WillerZ

Differential Revision: D9015012

fbshipit-source-id: 96b7e7ccb33583105f96d2170eeb159493b93ed0

Summary: Radix sort (as implemented by boost's spreadsort) is 2x faster than std::sort.

Reviewed By: nbronson

Differential Revision: D8875766

fbshipit-source-id: d88a323e6c14d58f0820c2d6d8c3d578c1305482

Summary:
- Fix up wrong order of template arguments in Expected generic
  - Create tests to check up all 3 forms of swap for Expected

Reviewed By: ericniebler

Differential Revision: D9013316

fbshipit-source-id: d4cebd83b268a4c5c551ac970f67b598f117fa73

Summary:
Despite the standard, `std::vector<bool>::const_reference` is not `bool` in
libcpp: http://howardhinnant.github.io/onvectorbool.html

Add the implicit ctor so that `f(dynamic)` can be invoked with `f(v[idx])`
where `v` is a `const vector<bool>` under libc++.

Reviewed By: ot

Differential Revision: D8992805

fbshipit-source-id: 0675174c2a247257238bb11b2c7b319653fe92a3

Summary:
Per title
I found that it was easier to bypass setContext (and not extend RequestContextScopeGuard) to achieve this result.

setShallowCopyContext now directly set the copy as current
the new unsetShallowCopyContext exclusively calls set/onset for the context data that was overriden. This assumes that cost will be fine because the callbackData_ sets are small or empty.
Similar reason they were split from requestData_ in the first place, for RequestContextScopeGuard efficiency.

(Note: this ignores all push blocking failures!)

Reviewed By: andriigrynenko

Differential Revision: D8943668

fbshipit-source-id: ad99177429de6b7b65bf95fa0e94334d73c3750d

Summary:
This guard maintains all the RequestData pointers of the parent (through shallow copy).
This allows to overwrite a specific RequestData pointer for the scope's duration, without breaking others.

We decided to keep the raw ptr interface, which required to implement a pseudo shared ptr to achieve the shallow copy behaviour.
Rest of the code is pretty straight forward. A few more lines than expected, due to introducing overrideContextData to avoid unecessary memory management (clearData) or warnings (setData).

The performance should be neutral for code not using the guard (std::atomic incr/decr).
The guard itself is pretty efficient at copying the values, though there is a slight worry about the keys (std::string). This might be a generic concern about current implementation, some form of cheap static would be better.
It also calls unecessarily onSet/onUnset. I will fix on top as it makes the change more complex.

Reviewed By: djwatson

Differential Revision: D8911351

fbshipit-source-id: 1692428382ace1d0b79bbc84a1db50efb4c7b489

Summary: This added significant cost, it will take effort to deploy, reverting for now

Differential Revision: D9007024

fbshipit-source-id: 04074b09a1a2b7f9b57e3d755a2754657dda21c2

Summary: Allow map to take a SemiFuture vector by changing the way the return type is deduced. Add overloads that take executor to apply.via and run the mapped tasks on a specified executor, and additionally return a Future that completes on that executor.

Reviewed By: andriigrynenko

Differential Revision: D7559540

fbshipit-source-id: f9480ea89fcfaa25a050ee7428dc69de300ccfde

Summary: Non-template functions in header files have to be marked as inline to avoid linker errors.

Reviewed By: yfeldblum

Differential Revision: D8983661

fbshipit-source-id: 8f003e9f4e2d40cb6122da8e9e0adacab00ed0fa

Summary:
When the param type is larger than `unsigned int`, the wider type `size{}` was
implicitly converted to the return type `unsigned int` in `findLastSet`. This
diff makes the conversion explicit.

Reviewed By: yfeldblum

Differential Revision: D8971589

fbshipit-source-id: 8828504c462e9296b84a746bcb7f701bc4a7d20e

Summary: Make ThreadEntry::elementsCapacity atomic

Reviewed By: yfeldblum

Differential Revision: D8963304

fbshipit-source-id: 0b37bbe97475a400e9b574b8285bde8f38a479f5

Summary:
Xcode wasn't impressed when I tried to import `folly::FixedString` from a Objective-C++ context.

This seem to satisfy Xcode's toolchain.

Reviewed By: lambdapioneer

Differential Revision: D8855137

fbshipit-source-id: 7bb3b1039b30241797ec7f3df7c0bbdeffca87bf

Summary:
There should be no expectations on what hash is internally used in dynamic, so
we don't need to maintain compatibility with `fbstring`, which hasn't been used
as string storage in `dynamic` for quite a while.

Reviewed By: yfeldblum, ot

Differential Revision: D8824634

fbshipit-source-id: 6765472aeeacb55c68b058f5dcc128f6b400bc95

Summary:
GLOG has `-logbuflevel` option that allows a user to specify the level above which none of the logs should be buffered. This is helpful as we can configure it such that `INFO` and all verbose logs are buffered before being output, but all logs above `INFO` should be flushed synchronously. This will ensure that all logs above a certain level are printed before any sort of crash.

This diff allows a user to specify a config `sync_level`. The value for this can be any `LogLevel`. Example config:

  .=WARN,akkio.cli=INFO; default:async=true,sync_level=WARN

The default value for GLOG's -logbuflevel is `0` (`INFO`).
To match GLOG's behavior, this diff sets the following as defaults:

  async=true,sync_level=WARN

Reviewed By: simpkins

Differential Revision: D8867555

fbshipit-source-id: 7ec30dfb41b2f3cd3568d70304db7a9fcf668779

Summary: Update default log level for Folly's logging to match that of Google's logging. This will make it easier to migrate between the two.

Reviewed By: simpkins

Differential Revision: D8941725

fbshipit-source-id: 14ed352d9a012f2604ff4329cc7cd038b2c0ee26