Summary:
SharedMutex used a saturating counter that records the number of
waiting lock() calls, but an ABA problem on futexWait could lead to a lost
wakeup when there was exactly 3 or 4 threads contending on the RW lock
in W mode.  This diff changes the kWaitingE count to be heuristic (it is
possible that the count says 1 but there are two waiters), saturates at
2 instead of 3 (because there is no benefit from differentiating those
two), and doesn't decrement the count on a successful wakeup.

Also, I noticed while debugging this that boost::noncopyable was causing
SharedMutex to be 8 bytes when it should only be 4.

One way the wakeup could be lost in the old code:

1. A calls lock()
2. A updates state <- kHasE
3. A returns
4. B calls lock()
5. B spins
6. B updates state <- kHasE + 1 * kIncrWaitingE
7. A calls unlock()
8. A updates state <- 0
9. A calls futexWake(), which returns 0
10. A calls lock()
11. A updates state <- kHasE
12. A returns
13. C calls lock()
14. C spins
15. C updates state <- kHasE + 1 * kIncrWaitingE
16. C calls futexWait, expecting kHasE + 1 * kIncrWaitingE
17. B calls futexWait, expecting kHasE + 1 * kIncrWaitingE
18. A calls unlock()
19. A updates state <- 0
20. A calls futexWake(), which returns 1
21. C receives the wakeup
22. C updates state <- kHasE
23. C returns
24. C calls unlock()
25. C updates state <- 0

B missed the wakeup that was intended for it (sent at step 9, wait
started at step 17), but went to sleep anyway because it saw the write
state at step 17. Now there are two waiters but only 1 recorded in the
SharedMutex, at which point failure is inevitable.

Test Plan:
1. DeterministicSchedule test using uniformSubset that can repro the problem
2. Test in production scenario that produced occasional deadlocks under high stress

Reviewed By: yfeldblum@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1980210

Tasks: 6720328

Signature: t1:1980210:1428623932:ef1c00c3f88154578b2b253ac0cfdbadf9f31d8c

Summary: Move this from a test to its own file in codec folder

Test Plan:
already has a unittest
fbconfig -r folly/wangle; fbmake runtests

Reviewed By: hans@fb.com

Subscribers: doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1959152

Signature: t1:1959152:1427935371:9d1338986df97fd94f98ad2bf08c731d229bc2b1

Summary: Copy of netty's line based decoder.

Test Plan:
unittests
fbconfig folly/wangle/codec; fbmake runtests

Reviewed By: hans@fb.com

Subscribers: doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1959155

Signature: t1:1959155:1427935150:e11280c5567df9ad9964dbb656aa090267856f57

Summary: Part 2 of pipeline.  Use OutputBufferingHandler, which is exactly the same output buffering thrift does currently.

Test Plan:
A couple canaries, unittests.
Specific issues of previous pipeline diffs I think are fixed already and should be fine with this one:
* Previously there were missing DestructorGuards.  I don't think anything in OutputBUfferHandler needs a DG
* previously broke http GET handling.  There is a unittest for it now.

Canary

Reviewed By: alandau@fb.com

Subscribers: doug, fugalh, alandau, bmatheny, mshneer, folly-diffs@, jsedgwick, yfeldblum, chalfant, vloh, andreib

FB internal diff: D1970949

Signature: t1:1970949:1428360621:a0db142032894525f69c2b144cf946d63f790fe1

Test Plan: ran it

Reviewed By: philipp@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1974936

Signature: t1:1974936:1428453023:1a83ed8336f75b745bffc633b8471231423b0fb0

Summary: the file needs to be opened with write-permissions before it can be mmaped with PROT_WRITE.

Test Plan: n/a

Reviewed By: philipp@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1974895

Signature: t1:1974895:1428451664:1106019abf02b9de659ce0d305e3d788ae7d60bc

Summary:
Is there any reason we shouldn't just cache the chain length everywhere?

Currently the pipeline does a lot of passing of buffers between IOBufQueues, I wonder if we can get even smarter about passing the length around

Test Plan: used in telnet server diff

Reviewed By: hans@fb.com

Subscribers: doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1959167

Signature: t1:1959167:1427934568:eb9a49514b2bb7d157879bb8efa99f12092d5e95

Summary:
LoopController and Fibers keep references to FiberManager, so implementing move-constructor for it is non-trivial.
The only purpose of move constructor was to have a create() static method, replaced it with a constructor accepting a type tag.

Test Plan: unit test + tao build

Reviewed By: stepan@fb.com, pavlo@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1971881

Signature: t1:1971881:1428374073:945d913e69eaa6f957dace981c23835105d91935

Summary: AsyncUDPServerSocket doesn't make it easy to write to the same socket you read from.  Add the socket as a callback param, similar to AsyncServerSocket

Test Plan:
fbconfig -r folly; fbmake dbg

Will fixup any other spots contbuild finds

Reviewed By: hans@fb.com

Subscribers: bmatheny, doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1948936

Signature: t1:1948936:1427841651:20d13d73c06d31c75056624f051a6fd35b9701fb

Summary: This diff allows fibers to explicitly yield execution to other fibers and the event loop

Test Plan: unit tests

Reviewed By: andrii@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant, tao-eng@

FB internal diff: D1965297

Signature: t1:1965297:1428082686:e524e9dd21b3fb951e1d3556e4cb3eedc3e6511a

Test Plan: contbuild

Reviewed By: pavlo@fb.com

Subscribers: alikhtarov, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1966698

Signature: t1:1966698:1428367351:62f2218c23d4911c15055917c0fbae31a2420903

Summary: We were forward-declaring `Executor` and `IOExecutor` for great compilation speed. However, this leaves users of this header to include at least one of those headers in their cpp file to actually use it, and that's kind of annoying. `Executor` and `IOExecutor` are not templated and are quite small, so it seems like the compilation speed benefit is minimal compared to the convenience factor, so this diff just includes the two headers. (Probably including `Executor.h` is redundant since `IOExecutor.h` probably includes it, but for completeness and explicitness, and in case `IOExecutor` also just forward-declares `Executor` now or in the future.)

Test Plan: stuff still builds

Reviewed By: davejwatson@fb.com

Subscribers: fugalh, exa, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1970179

Signature: t1:1970179:1428351076:e9c3700a868688035e7ff50486b8cead751d3c02

Summary: This adds local type for each FiberManager. Only local of given type can be created on fibers of this FiberManager. Locals of other types will be just treated as regualar thread-locals.

Test Plan: unit test

Reviewed By: bwatling@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1969739

Signature: t1:1969739:1428345931:aff5deb526c179158e5881b29330ff3f6698149a

Summary: title + some logging around

Test Plan: mcrouter unit tests

Reviewed By: andrii@fb.com

Subscribers: alikhtarov, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1965097

Signature: t1:1965097:1428103637:341ff705c9d11c730197828256ec0b790ee7afaa

Summary: promote the sockets vector to a shared_ptr, since both ServerWorkerPool and ServerBootstrap use it.  Otherwise there are destruction order issues between ServerBootstrap and any IOThreadPoolExecutor you use

Test Plan: Saw use after free in D1942242, gone after this.

Reviewed By: yfeldblum@fb.com

Subscribers: chalfant, doug, fugalh, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1947553

Signature: t1:1947553:1427484417:5b78f5c9c70d244d3f52a6f71b6d1fab7b29d106

Summary:
This simplifies TAO fibers locals, using FiberManager based fiber-local storage.
This depends on D1958135.

Test Plan: integration tests

Reviewed By: bwatling@fb.com

Subscribers: alikhtarov

FB internal diff: D1962214

Signature: t1:1962214:1427997755:b546b9039382a7600f234b0a2a60cc96da34e662

Summary: This adds fiber-local context, which behaves more like static objects+fork rather than thread-locals.

Test Plan: unit test

Reviewed By: pavlo@fb.com, bwatling@fb.com

Subscribers: rushix, alikhtarov, bwatling

FB internal diff: D1958135

Signature: t1:1958135:1427999426:8e4b89f4af53a1a119b2e5a765fb549dd8442c50

Summary:
Some things like gSOAP, initialize SSL only to have SSLContext stomp over their
work. Add a method to allow flagging SSLContext as "initialized" to use the
existing global state.

Test Plan:
Tested running mcrouter and paymentnegined to verify existing
functionality appears normal.

Reviewed By: subodh@fb.com

Subscribers: ssl-diffs@, folly-diffs@, yfeldblum, chalfant, dihde

FB internal diff: D1959936

Tasks: 6655251

Signature: t1:1959936:1427994292:8b2be1742ef17a5ec2c7b3ad37787d2cf4d142a6

Summary: facepalm

Test Plan: Built proxygen OSS that depends on this symbol

Reviewed By: davejwatson@fb.com

Subscribers: doug, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1963679

Signature: t1:1963679:1428006035:2c4ceffc046b995431cde2fbcef757fa7ea1ea0b

Summary:
The mcrouter fibers library is quite general purpose and reusable by other projects. Hence I'm moving it into folly.

Test Plan:
fbconfig -r folly/experimental/fibers && fbmake runtests
fbconfig -r mcrouter && fbmake runtests
fbconfig -r tao && fbmake
fbconfig -r ti && fbmake

Reviewed By: andrii@fb.com

Subscribers: vikas, zhuohuang, jmkaldor, jhunt, pavlo, int, aap, trunkagent, fredemmott, alikhtarov, folly-diffs@, jsedgwick, yfeldblum, chalfant, chip

FB internal diff: D1958061

Signature: t1:1958061:1428005194:b57bfecfe9678e81c48526f57e6197270e2b5a27

Summary: Bind via port or address, similar to tcp

Test Plan: I wrote a unittest that tested v4 vs v6 binding - can't check it in because we have v6 only clusters though.  Not sure how eles to write a unittest without picking specific ports

Reviewed By: hans@fb.com

Subscribers: doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1948938

Signature: t1:1948938:1427841721:621031320981bf366a8252a0ea1d4491b694ea24

Summary:
TODO item, trying to remove unecessary dependencies on thrift

Test Plan: Unit tests

Reviewed By: davejwatson@fb.com

Subscribers: doug, fbcode-common-diffs@, davejwatson, andrewcox, alandau, bmatheny, anca, darshan, mshneer, folly-diffs@, bil, yfeldblum, haijunz, chalfant

FB internal diff: D1960215

Signature: t1:1960215:1427920934:8abd7e94c50676b05bf7ff79800df0db1bd04266

Summary: These parallel the MockTAsync* from thrift/lib/cpp/test.  Once all the users of the thrift versions are gone they can be deleted

Test Plan: Unit tests

Reviewed By: yfeldblum@fb.com, alandau@fb.com

Subscribers: doug, net-systems@, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1959979

Signature: t1:1959979:1427917909:19af219f88dd6847a064da986dd30765e29bdc99

Summary: These tests belong with the code that they test.  The old tests had a couple dependencies on TSocket/TSSLSocket, so I wrote a BlockingSocket wrapper for AsyncSocket/AsyncSSLSocket

Test Plan: Ran the tests

Reviewed By: alandau@fb.com

Subscribers: doug, net-systems@, alandau, bmatheny, mshneer, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1959955

Signature: t1:1959955:1427917833:73d334846cf248f8bb215f3eb5b596df7f7cee4f

Summary:
Adding new atomic data structure from the mcrouter project.

Test Plan: fbconfig -r mcrouter && fbmake runtests

Reviewed By: andrii@fb.com

Subscribers: alikhtarov, folly-diffs@, yfeldblum, chalfant, achao, jpearce

FB internal diff: D1960219

Signature: t1:1960219:1427921204:78e5313ea916b8a249d32e31cc7ba1aa9e890d95

Summary:
See the test case and D1958860.

I don't really know why I chose one over the other. This fixes a bug. So
it's better?

Test Plan: Run all the tests?

Reviewed By: yfeldblum@fb.com

Subscribers: folly-diffs@, jsedgwick, yfeldblum, chalfant, over

FB internal diff: D1960740

Signature: t1:1960740:1427927644:25093b049a1519d7c869ee7043f3caced4cc971e

Summary:
I have 2 local buffers and instead of allocating iobufs
on the heap, I can simply use iovec on the stack to send.

Test Plan: Unit tests and turn server.

Reviewed By: davejwatson@fb.com

Subscribers: folly-diffs@, ehrhardt, yfeldblum, chalfant, paramr

FB internal diff: D1956201

Signature: t1:1956201:1427918649:09f00399fd9e8ed3fe62be43b19adbf0a5a3f3b0

Test Plan: unittests

Reviewed By: jbrewer@fb.com, ashishsharma@fb.com

Subscribers: maxime, folly-diffs@, yfeldblum, chalfant

FB internal diff: D1956101

Signature: t1:1956101:1427828321:2d828e6f2c06c6dcd6e7baa3ed5e72ee59d9b77f

Summary:
From reading the docs, I assumed that casting exceptions would be caught.  Let's clarify this.

Test Plan: readingiskey

Reviewed By: yfeldblum@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant

FB internal diff: D1960186

Signature: t1:1960186:1427920471:b7aa2af38a90a986418b98294fc0f69e678f0d1e

Summary:
Taking this trick that is used in the fibers library. We can keep 64
bytes of space inside `Core` to allocate the callback lambda into,
instead of having `std::function` do another `malloc`. This seems to
greatly improve the synthethic benchmark, and hopefully production
workloads, too, by reducing the number of mallocs.

64 bytes were picked because it fits all the lambdas in the futures
tests. We might want to adjust this based on production data...?

https://fb.intern.facebook.com/groups/715931878455430/permalink/837898842925399/

Test Plan: Run all the tests for all platforms, compilers, and Windtunnel.

Reviewed By: hans@fb.com

Subscribers: chalfant, meisner, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1931620

Signature: t1:1931620:1427841595:6ec667b58980be232dfb116bc316148bb67de4fc

Summary: In a couple places in ServerBootstrap there is code that needs to run in the EB, but if we are already in the EB, it's fine to run it inline.  Maybe this should be a method on EB directly?  There is runInEventBaseThreadAndWait(), but it explicitly disallows this usage.

Test Plan: used in D1942242, deadlocks without this, since stop() was called in the same eb

Reviewed By: yfeldblum@fb.com

Subscribers: chalfant, doug, fugalh, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1947581

Signature: t1:1947581:1427831021:d1d08ff9a4a00501d6be60670709fcb17af04134

Summary:
The current behaviour of SSLContext is subject to a bug where an instance going
out of scope at the wrong time can decrement the global refcount to 0, causing
the destructor to destroy the SSL context. Instead, this requires callers to
explicitly uninitialize the SSLContext instance and assume the risk of wrongly
destroying the global SSL context.

Test Plan:
Tested with mcrouter

Reviewed By: subodh@fb.com

Subscribers: afrind, ssl-diffs@, folly-diffs@, yfeldblum, chalfant, dihde, melitam

FB internal diff: D1949649

Tasks: 6358211

Signature: t1:1949649:1427854689:aea2dc801f63256ff64188b0f7a15121dcecee69

Summary: as title

Test Plan: run unit tests

Reviewed By: yfeldblum@fb.com

Subscribers: ming, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1955074

Summary:
If an MPMCQueue was initialized with an explicit zero capacity, it would
try to compute stride for zero and trigger SIGFPE which pretty fatally
killed the process -- but in a way that required gdb to figure out the
root cause.

This replaces that with a std::invalid_argument exception, which
includes a description of the problem and should make fixing this user
error much faster.

Test Plan:
GTEST unit test added to verify behaviour; if this didn't work it would
SIGFPE and abort the test script, which is probably a good indicator
that something went wrong. :)

fbconfig -r folly && fbmake runtests

Reviewed By: ngbronson@fb.com

Subscribers: chalfant, folly-diffs@, yfeldblum, rkomorn

FB internal diff: D1930978

Signature: t1:1930978:1427740315:cc06a8b9f3c314b956ae41f813b2f904d3e979c9

Summary: Since Acceptor can be used for TCP or UDP, make an empty default TCP accept function so subclasses don't have to.

Test Plan:
built D1942242, no build errors

contbuild

Reviewed By: yfeldblum@fb.com

Subscribers: doug, fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant

FB internal diff: D1948940

Signature: t1:1948940:1427498977:26b7bb23e3367ff6695dad86ebf0e60637815a7b

Summary:
[Folly] EventBase::runImediatelyOrRunInEventBaseThreadAndWait.

When you have code that you need to run in the event loop and wait for it to finish, and you yourself might be in the event loop but might be in another thread instead.

Test Plan:
Unit tests:
* `folly/io/async/test/EventBaseTest.cpp`.

Reviewed By: davejwatson@fb.com

Subscribers: folly-diffs@, yfeldblum, chalfant, agallagher, njormrod, ldbrandy, brettp, dougw

FB internal diff: D1953110

Signature: t1:1953110:1427751076:ad2c9f4d5b65ef952cba94b06be887672ee44583

Summary:
as title.

Test Plan: run unit tests

Reviewed By: yfeldblum@fb.com

Subscribers: ming, fugalh, folly-diffs@, jsedgwick, yfeldblum, ridge@

FB internal diff: D1946589