Summary:
Without a gadget like this, it's really hard to test logging output. With it, it's really easy. I found about 50 callsites to the various functions across several projects, so folly seems appropriate.

PS The patterns are functions for two reasons:
- Static variables are a pain.
- This leaves the option of adding an optional argument, so you can grep for a particular kind of error string.

Test Plan: unit test

Reviewed By: yfeldblum@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1933439

Signature: t1:1933439:1427345479:5b3d1c6566a026fdbccb16b382211688e327ea1a

Summary: There are about 40 callsites to these across a couple of projects, and they seem generally useful.

Test Plan: ```fbconfig folly/experimental/test && fbmake runtests```

Reviewed By: yfeldblum@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1933415

Signature: t1:1933415:1427345307:6587eea3dac74c5d841950ace3c3501d6e3dbe4a

Summary:
TemporaryFile, TemporaryDirectory, and ChangeToTempDir should all be moveable
objects, but not copiable.  Define default move constructors and move
assignment operators for these classes.  This will prevent copy constructor and
copy assignment operators from being implicitly defined.

Test Plan:
Used this in a new test to write a helper function which created and returned
a new TemporaryFile object using the move constructor.

Reviewed By: yfeldblum@fb.com

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

FB internal diff: D1945134

Signature: t1:1945134:1427342944:3428327e797ce4b3d362f9a2d2276de6d8b96137

Summary:
1] The lambda should ble able to return a `Try<T>`. Maybe? Can a `then`
return a `Try<T>` actually? Can fix this with `resultOf`. (Doubling the number of functions to 4.)

2] `initial` and `func` have to be copyable.

Test Plan: Added tests.

Reviewed By: hans@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1870996

Tasks: 6025252

Signature: t1:1870996:1427318511:2ae5894b79022da88990835b26d35c4520fdbd29

Summary: Make it easy for people to mark code as deprecated

Test Plan: Chose a random file and added the FOLLY_DEPRECATED macro to it

Reviewed By: yfeldblum@fb.com

Subscribers: ps, folly-diffs@, yfeldblum

FB internal diff: D1943248

Signature: t1:1943248:1427316689:b3305d134f374697e93d36bafbf0961eec1ef68a

Summary:
vsnprintf can return fewer bytes and bytes_used if
we print a string containing '\0' using a width
specifier.

Test Plan: -- ran all tests

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1915035

Signature: t1:1915035:1426799341:4aaea928c4bdde1998bf66cf9e2732a53572c6e3

Summary:
Original diff D1800100, reverted in D1895181.  Issue seems to have been caused by a copy constructor issue.

Fixes: Remove copy constructor, move contructor only.  Separate stop() and join(), since join() can happen only after all stop()s have completed when reusing the same IOThreadPoolExecutors.

Test Plan: build and unit tests of relevant product

Reviewed By: praveenr@fb.com

Subscribers: trunkagent, doug, fugalh, alandau, bmatheny, mshneer, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1901718

Tasks: 6431975

Signature: t1:1901718:1426885577:46b63bfe117df207be3d273b953c100249c1a7da

Blame Revision: D1895181

Summary: It's convenient to be able to write tempfiles in the current directory. This provides a one-liner way of doing that in tests.

Test Plan: unit test

Reviewed By: yfeldblum@fb.com

Subscribers: simpkins, folly-diffs@, yfeldblum

FB internal diff: D1931918

Signature: t1:1931918:1426913634:f988fb3c5061f5909e309dcaf42742d9b2ed18c6

Summary: We want to print all destructor stack-traces if Singleton destruction happens eventually (even after destroyInstances() was done).

Test Plan:
unit test

Reviewed By: chip@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1929881

Signature: t1:1929881:1426878091:5993d544c0f84bdbf8bcdd420ef01fb7bf88ac3f

Summary:
major changes:

1) ServerSocketFactory and AsyncSocketBase to abstract the differences between UDP and TCP async socket.  Could possibly push some of this to the sockets themselves eventually
2) pipeline() is a pipeline between accept/receive of a UDP message, and before sending it to workers.  Default impl for TCP is to fan out to worker threads.  This is the same as Netty.  Since we don't know if the data is a TCP socket or a UDP message, it's a void*, which sucks (netty uses Object msg, so it isn't any different).

Test Plan: Added lots of new tests.  Doesn't test any data passing yet though, just connects/simple receipt of UDP message.

Reviewed By: hans@fb.com

Subscribers: alandau, bmatheny, mshneer, jsedgwick, yfeldblum, trunkagent, doug, fugalh, folly-diffs@

FB internal diff: D1736670

Tasks: 5788116

Signature: t1:1736670:1424372992:e109450604ed905004bd40dfbb508b5808332c15

Summary:
This code is only used in a test so far.

Basically it looks like Pipeline has some dependency issues - any addBack() pipelines have to be deleted *after* the main pipeline is destroyed.  Ideally if the pipeline is already closed, the destruction order wouldn't matter.  There is currently no removeBack() call either.   This is a quick fix for the test to just delete stuff in the right order, we can discuss a better solution when @jsedgwick returns

Test Plan: fbconfig --sanitize=address --with-project-version=clang:3.5 --clang folly/wangle/service && fbmake runtests

Reviewed By: hans@fb.com

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

FB internal diff: D1903200

Tasks: 6415578

Signature: t1:1903200:1426528298:e109dcc0ec586a505a26cd95a6f20434d22cbd37

Summary:
In my tests, using djb2 was much worse for any sizable workload. Just use SpookyHashV2.

Test Plan: comment only

Reviewed By: tudorb@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1906439

Signature: t1:1906439:1426117575:f88b7b28b578092c1716433e21150d423d4e94a7

Summary:
Calling getaddrinfo from a static constructor is not the most
reliable thing to do. Stop doing it.

Test Plan: existing tests

Reviewed By: davejwatson@fb.com

Subscribers: dancol, mzlee, shikong, kmdent, fma, bmatheny, benyluo, ranjeeth, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1924578

Tasks: 6534662

Signature: t1:1924578:1426718586:d73bc2f001095e66fa77fde9c027af050cc26d2a

Summary: I thought this might fix #6120972. But it doesn't. Still a bit of a cleanup in my opinion.

Test Plan: Run all the tests?

Reviewed By: hans@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1907259

Signature: t1:1907259:1426613567:9e33fe7e9e8a36ba006d4aee604086a56f128893

Summary:
Sometimes we only want to log if enough time has passed, e.g. when logging
inside of a loop doing work to detect if things are slow. Add an option for
that.

Test Plan:
build and unit tests of folly/experimental

Reviewed By: lesha@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1909055

Signature: t1:1909055:1426627731:6d3ad94fd71967ec89ffebc90cd2907dd1631d36

Summary: Ooops during port ;)

Test Plan: unit test

Reviewed By: agoder@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1905639

Signature: t1:1905639:1426171227:a6e415046a85f098ac090f069476204fb0367c42

Summary: Signed-off-by: Nicholas Ormrod <njormrod@fb.com>

Test Plan: Clicked link, gtest started downloading

Reviewed By: markisaa@fb.com

Subscribers: sdwilsh, folly-diffs@, yfeldblum

FB internal diff: D1901849

Tasks: 6255850

Signature: t1:1901849:1426097071:e887ed8749c70d5e15877082ac0175ce3b56647e

Summary:
BackoffTimeout disallow copy construction, copy assignment, move
construction, move assignment, and default construction.

Closes https://github.com/facebook/folly/pull/146

Test Plan: runtests

Reviewed By: ldbrandy@fb.com

Subscribers: lins, anca, folly-diffs@, yfeldblum

FB internal diff: D1912521

Signature: t1:1912521:1426268413:6edb2d8203d1efd1e825816f03be115ac46e55ca

Summary:
It seems we might avoid temporaries.  To do so we pass arguments
directly to constructors with the help of emplace_back member.

Test Plan:
all folly/tests, make check for 37 tests, passed.

Closes https://github.com/facebook/folly/pull/150

Reviewed By: ldbrandy@fb.com

Subscribers: lins, anca, folly-diffs@, yfeldblum

FB internal diff: D1912505

Signature: t1:1912505:1426268158:086882bb53f3d79c3f3b7b2c362318f09b5ee3be

Summary:
AsyncServerSocket disallow copy construction, copy assignment,
move construction, move assignment, and default
construction.

Closes https://github.com/facebook/folly/pull/148

Test Plan: all folly/tests, make check for 37 tests, passed.

Reviewed By: ldbrandy@fb.com

Subscribers: lins, anca, folly-diffs@, yfeldblum

FB internal diff: D1912488

Signature: t1:1912488:1426267982:a9690ce9429016f89630f0ded64b7be9ff80c39d

Summary: backslash

Test Plan: tests

Reviewed By: aap@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1920872

Signature: t1:1920872:1426624366:c984fecb5bd0c292d5a8309fb320a48872fff6db

Blame Revision: D1890511

Test Plan:
unit tests

Reviewed By: bwatling@fb.com

Subscribers: stepan, folly-diffs@, yfeldblum, trunkagent, vikas, alikhtarov

FB internal diff: D1890511

Tasks: 6311387

Signature: t1:1890511:1425924980:71af7c12a09a86b280dc3c9a9ef0756bf56bf639

Summary: Apparently `configure` creates this subdirectory and then the curl and unzip commands don't run, and then `make check` fails. Instead, do it if the zip file doesn't exist.

Test Plan:
git clone https://github.com/facebook/folly.git
cd folly/folly
/path/to/this/bootstrap-osx-homebrew.sh
make
make check

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: exa, folly-diffs@, yfeldblum, davejwatson

FB internal diff: D1882472

Signature: t1:1882472:1425920470:bdab25967d3b8e52c690d5627168077c65829b92

Summary: for consistency with exception and exception_ptr functions provided in String.h

Test Plan: unit

Reviewed By: vloh@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1905087

Tasks: 5961362

Signature: t1:1905087:1426101740:670ceab5140250bbecdd1247025d3d70b7774690

Summary:
Added folly::Future<T>::poll() function with the following semantics:
poll() checks if the promise has been fulfilled, if so it will extract the value of the resulting Try<T> to construct a new Try<T> that is wrapped in an Optional<Try<T>>. If the promise has not been fulfilled an empty Optional is returned.

Test Plan: Added two tests to SugarTest.cpp: one where the promise has been fulfilled and one where it hasn't.

Reviewed By: hannesr@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, arturg, yfeldblum

FB internal diff: D1909480

Tasks: 6166875

Signature: t1:1909480:1426280247:6b239c0f1a15c25ce7664afb4bfb3899993c5775

Summary:
Seems useful to do without passing in a totally custom queue. Makes
the client code a bit simpler.

Test Plan: used it, saw low memory usage and no crash

Reviewed By: davejwatson@fb.com

Subscribers: trunkagent, iaroslav, fugalh, folly-diffs@, jsedgwick, yfeldblum, slarsen

FB internal diff: D1907874

Signature: t1:1907874:1426268010:3159ae339b51f5dbc7fe034644bbc968b92b072c

Summary:
I will be using multi-buf UDP send soon, so adding the
support in folly::AsyncUDPSocket

Test Plan: Unit tests and turn server

Reviewed By: davejwatson@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1907189

Signature: t1:1907189:1426266951:046198e0a009fef085ac7eb44f054c67dfb16ba3

Summary:
Add a helper method to efficiently check if the cursor is at the end of the
IOBuf chain.  This is equivalent to (cursor.totalLength() > 0), but it doesn't
need to walk the entire chain just to tell if it is at the end or not.

Test Plan: Updated the unit tests to contain some checks for isAtEnd().

Reviewed By: jasmeetbagga@fb.com

Subscribers: trunkagent, doug, net-systems@, exa, folly-diffs@, yfeldblum

FB internal diff: D1875345

Signature: t1:1875345:1425006512:49ac246fd0ac7937fdcd6cf1359a841f048c444e

Summary: This used to be protected before.

Test Plan: folly/futures tests

Reviewed By: andrii@fb.com

Subscribers: trunkagent, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1907063

Signature: t1:1907063:1426116657:d7430304d5f72a048396e83f8dc6b5a92198fb29

Summary:
By default, CPUThreadPoolExecutor uses 100 MB of rss for the CPU queue. This is
substantially higher than expected.

Reduce the default queue size so that it uses much less memory upfront, down
to about 6 MB going by the heap profile.

Reviewed By: davejwatson@fb.com

Subscribers: mwa, ott, iaroslav, jrsherwood, aflock, slarsen, davejwatson, trunkagent, fugalh, folly-diffs@, jsedgwick, yfeldblum

FB internal diff: D1900539

Tasks: 6453427

Signature: t1:1900539:1426103805:34fb7b081058fbde89370b5d9ec24ea572c4b0e2

Summary: D1798929 broke the automake folly build

Test Plan:
1. careful visual inspection
2. build

Reviewed By: alikhtarov@fb.com

Subscribers: folly-diffs@, yfeldblum

FB internal diff: D1906281

Signature: t1:1906281:1426106340:621f1e7d2fb18ae2ec5dc604dea0d8ad4353486e

Summary:
SharedMutex is a reader-writer lock.  It is small, very fast, scalable
on multi-core, and suitable for use when readers or writers may block.
Unlike most other reader-writer locks, its throughput with concurrent
readers scales linearly; it is able to acquire and release the lock
in shared mode without cache line ping-ponging.  It is suitable for a
wide range of lock hold times because it starts with spinning, proceeds
to using sched_yield with a preemption heuristic, and then waits using
futex and precise wakeups.

SharedMutex provides all of the methods of folly::RWSpinLock,
boost::shared_mutex, boost::upgrade_mutex, and C++14's
std::shared_timed_mutex.  All operations that can block are available in
try, try-for, and try-until (system_clock or steady_clock) versions.
Both reader-priority and writer-priority versions are provided.
Writer-priority is the default at the moment.

In my tests SharedMutex is as good or better than the other reader-writer
locks in use at Facebook for almost all use cases, sometimes by a wide
margin.  (If it is rare that there are actually concurrent readers
then RWSpinLock can be a few nanoseconds faster.)  I compared it to
folly::RWSpinLock, folly::RWTicketSpinLock64, boost::shared_mutex,
pthread_rwlock_t, and an internal RWLock that uses spinlocks to guard
its state and pthread_mutex_t+pthread_cont_t to perform blocking.
(The other ReadWriteMutex-s I found use pthread_rwlock_t underneath.)
It is generally as good or better than the rest when evaluating size,
speed, scalability, or latency outliers.  In the corner cases where
it is not the fastest (such as single-threaded use or heavy write
contention) it is never very much worse than the best.  See the bottom
of SharedMutexTest.cpp for lots of microbenchmark results.

Test Plan:
1. new unit tests
2. new microbenchmarks included here
3. uncommitted microbenchmark from bmaurer's RWSleepLock
4. replace admarket's RWSpinLock and RWLock with SharedMutex, observe
neutral adindexer perf in canary
5. replace multifeed's thrift ReadWriteLock with SharedMutex, observe
neutral perf in canary

Reviewed By: hans@fb.com

Subscribers: fbcode-common-diffs@, tnovak, march, davejwatson, trunkagent, philipp, folly-diffs@, yfeldblum, bwatling, bmaurer, bol, marccelani, adri, strager, macsyz, dzhulgakov, zamsden

FB internal diff: D1798929

Signature: t1:1798929:1425575976:1c9221317eaa47628a2b8c374f90c7a2d4e3f0f9

Summary: Some unit tests owned by my team are failing due to segmentation fault in SingletonHolder<T>::registerSingletonMock -> SingletonHolder<T>::destroyInstance.

Test Plan: Run folly unit tests and my unit tests.

Reviewed By: henryf@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1873889

Signature: t1:1873889:1425925156:29d54092939d7e9debea3fd55f7105fd320e987e

Blame Revision: 91f4942e

Summary:
This is a validator for  JSON schema (http://json-schema.org/) that works on
folly::dynamic. Apparently there are no good open source ones for C++,
especially not if you want to use folly::dynamic. I am going to use this to
validate JSON configs.

It supports basically everything from the standard, except for fetching schemas
via http, and using id refs. It supports enough to check schemas against the
metaschema.

Currently you can define a schema that will crash on validation, if it's
infinitely self-recursive. See the unit test case that reproduces this.
Fixing this seems hard though, so I didn't bother. It would also probably
be slower for normal usage.

Test Plan: unit test

Reviewed By: lesha@fb.com

Subscribers: trunkagent, folly-diffs@, yfeldblum

FB internal diff: D1847657

Signature: t1:1847657:1425605163:635dc523aeda1b588c3634d0dc1a48d50a53db79

Summary:
Remove unnecessary includes from FBVector

Gonna see just how cleaned-up sandcastle really is :P

Test Plan: Fix errors shown in contbuild

Reviewed By: njormrod@fb.com

Subscribers: cold-storage-diffs@, jcoens, ldbrandy, trunkagent, oleksandr, netego-diffs@, mmandal, weiyan, ws_dev_diffs, jmkaldor, jhunt, fbcode-common-diffs@, njormrod, folly-diffs@, yfeldblum

FB internal diff: D1873145

Signature: t1:1873145:1425505591:9cb345053833afa70f543e2f7acd310ab80b8676

Summary:
Cleans up the httpserver startup code nicely.  The only major change to ServerBootstrap was a check if bind failed to throw an exception.

(depends on D1732895)

Test Plan:
fbconfig -r folly/wangle/bootstrap proxygen/httpserver; fbmake runtests

fbconfig -r dfsrouter; fbmake runtests

Reviewed By: hans@fb.com

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

FB internal diff: D1800100

Signature: t1:1800100:1424733970:67a61a22d2affadea16d2fd725003915326077b2