Summary:
* folly/stats/Histogram-defs.h (HistogramBuckets): Take the unusual
approach of converting "numBuckets" to signed, because we cannot
cast "max-min" (a known positive value) to an unsigned type --
we don't have an unsigned variant of ValueType.
This avoids the following error from gcc-4.9:

folly/stats/Histogram-defs.h:41:31: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: ldbrandy@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1770129

Tasks: 5941250

Signature: t1:1770129:1420745311:c447e59f1730abafdf0b962e70f0886ae1d48db1

Summary:
* folly/detail/FileUtilDetail.h (wrapvFull): Change type of result
variable from ssize_t to size_t: this required changing r == -1 to
r == (size_t)-1.

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo
Also run fbmake runtests, and confirm that the results are
the same with and without this change.

Reviewed By: lucian@fb.com

Subscribers: folly-diffs@

FB internal diff: D1772171

Tasks: 5941250

Signature: t1:1772171:1420743142:1f9e02006e2d77a0c9451bae7965fb28617d95d6

Summary:
* folly/wangle/futures/Future-inl.h (whenAll): Do not compare
signed (std::distance) with unsigned(size_t): add an assertion
to eliminate the possibility of negative, then assign to a new
size_t "n".

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: jsedgwick@fb.com

Subscribers: trunkagent, fugalh, folly-diffs@

FB internal diff: D1770668

Tasks: 5941250

Signature: t1:1770668:1420736965:fc722657a2ec523052fd96c33d65d5ca24aae61c

Summary:
* folly/FBString.h (operator>>): Since istream.width() is signed,
handle the case of a negative width. This avoids risk that "n"
will be less than 0 when compared against unsigned "extracted".
However, to suppress the following warning, we must also explicitly
convert "n" to size_t before comparing:

folly/FBString.h:2326:22: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: trunkagent, net-systems@, njormrod, folly-diffs@

FB internal diff: D1770460

Tasks: 5941250

Signature: t1:1770460:1420679684:b262eb31e6511b6311bebf0fbc29099471648b36

Summary: as discussed in another diff, this might help with NRVO

Test Plan: unit

Reviewed By: hans@fb.com

Subscribers: trunkagent, fugalh, folly-diffs@

FB internal diff: D1764921

Signature: t1:1764921:1420677311:c6b63d7bf04c0e17283117b3edef798c288e5fbb

Summary: as above, fixes builds

Test Plan: compiled thrift + mcrouter

Reviewed By: seanc@fb.com

Subscribers: seanc, fugalh, folly-diffs@

FB internal diff: D1771910

Signature: t1:1771910:1420733490:7f33e57a5853395cab786e5d35d4c15c75a15c5a

Summary:
One header at a time, starting with the small fry

I'm allowed to drink while I do this right? Good, because I don't think I ever had a choice.

Test Plan: generated doxygen and looked decent http://home.fburl.com/~jsedgwick/html/classfolly_1_1wangle_1_1Try.html

Reviewed By: davejwatson@fb.com

Subscribers: trunkagent, fugalh, njormrod, folly-diffs@

FB internal diff: D1677730

Tasks: 5480262

Signature: t1:1677730:1415899240:bdd03569a82be1c8def8c13786eae39b4a2a2f94

Summary:
integrate exception_wrapper everywhere, and deprecate public methods that take ptrs directly to discourage their use
note that this will break for throwing non-exceptions, which is probably fine

this change opens the door to interesting optimizations for those interested, e.g. Future::then<Exn1, Exn2>(/* func throwing Exn1 and Exn2 */) that autowraps the given types into the resultant future

new benchmark:
```
throwAndCatch                                               23.69us   42.21K
throwAndCatchWrapped                             119.53%    19.82us   50.45K
throwWrappedAndCatchWrapped                      350.16%     6.77us  147.80K
```

Test Plan: existing unit tests, suspected potential perf wins confirmed by benchmark, will wait for windtunnel to see other wins/regressions

Reviewed By: hans@fb.com

Subscribers: search-fbcode-diffs@, apodsiadlo, alikhtarov, andrii, trunkagent, fugalh, njormrod, folly-diffs@, bmatheny

FB internal diff: D1644912

Signature: t1:1644912:1420731849:3dc658dc03bfd6e75d61158808c7dad96092ecfb

Summary:
* folly/String-inl.h (humanify): Count with a signed type.
Otherwise, gcc-4.9 fails with e.g.,
folly/String-inl.h:596:33: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
folly/String-inl.h:601:32: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: trunkagent, folly-diffs@

FB internal diff: D1770451

Tasks: 5941250

Signature: t1:1770451:1420704354:c841ca453a5586fbf474535ca26cef17f95427dd

Summary:
* folly/AtomicHashArray.h (numEntries_, numPendingEntries_):
Use an unsigned type for each of these.  They count things, can
never go below 0, and are compared to unsigned values.
Otherwise, gcc-4.9 would emit this:
folly/AtomicHashArray-inl.h:153:38: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: trunkagent, folly-diffs@

FB internal diff: D1770695

Tasks: 5941250

Signature: t1:1770695:1420683354:bfa4775bc2f8aab74e34772308a5c8b1779243b8

Summary:
* folly/AtomicHashMap-inl.h (insertInternal): Do not declare
nextMapIdx to be signed ("int"), since we compare it against
variables of unsigned type.  Otherwise, gcc-4.9 would give this
diagnostic:
folly/AtomicHashMap-inl.h:99:18: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
complaining about this comparison:
if (nextMapIdx >= kNumSubMaps_ ||

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: folly-diffs@

FB internal diff: D1770683

Tasks: 5941250

Signature: t1:1770683:1420683505:4452c7cb4f14f098be089601be906884036348ed

Summary:
Address multiple -Werror=sign-compare issues exposed when building
tao with gcc-4.9.
In most of these changes I've changed the type of the index in
a for-loop from int to size_t.  The important thing is to use
an unsigned type when the limit is also unsigned.  I choose size_t
because the general recommendation (when writing portable code)
to avoid size-tied types like uint32_t and uint64_t unless you
have a very good reason to require them.

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 tao/server && fbmake dbgo

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1766651

Tasks: 5941250

Signature: t1:1766651:1420594537:56ef53ca233e1649469db9570942c1d5dd47cf6d

Summary:
* folly/test/ForeachTest.cpp: Change a "1" to "1U", so it matches
the signedness of the size_t upper bound.
Otherwise, gcc-4.9 fails with e.g.,
folly/Foreach.h:194:16: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: folly-diffs@

FB internal diff: D1770603

Tasks: 5941250

Signature: t1:1770603:1420679246:56ef62ac7fa4413a4ad6310c3381a12bdc59e64c

Summary:
* folly/stats/BucketedTimeSeries-defs.h (BucketedTimeSeries):
Assume that maxDuration is never negative, and cast the signed
duration_.count() to size_t, to avoid this error from gcc-4.9:

folly/stats/BucketedTimeSeries-defs.h:38:18: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1770171

Tasks: 5941250

Signature: t1:1770171:1420669115:61e6b8d3248f88b25736322c7066af015209fba5

Summary:
* folly/Format-inl.h (folly): fwrite returns size_t, not ssize_t.
Fixing this avoids the following diagnostic from gcc-4.9:
folly/Format-inl.h:299:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1770155

Tasks: 5941250

Signature: t1:1770155:1420668733:62593231d35f5874521dba575f23b68891b2a4f9

Summary:
* folly/Format-inl.h (IndexableTraitsSeq::at): Add an explicit
int-to-size_t cast (ok here, since we've just confirmed
that the value is not negative) to avoid this error from gcc-4.9:

folly/Format-inl.h:947:29: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: tjackson@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1770193

Tasks: 5941250

Signature: t1:1770193:1420670569:83ac19c2ca8cd408d7c86d7dce49e2d4b418941a

Summary:
* folly/test/SpinLockTest.cpp (trylockTestThread):
Change parameter type from int to size_t, to fix these:
folly/test/SpinLockTest.cpp:67:25: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
folly/test/SpinLockTest.cpp:82:60: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: net-systems@, folly-diffs@

FB internal diff: D1770564

Tasks: 5941250

Signature: t1:1770564:1420674373:fa3020398e2df66590eb71f798419b6f555d07c4

Summary: CPUObserver observe events happen in different threads than the IOThreadPool ones.

Test Plan: fbconfig folly/wangle/concurrent/test && fbmake runtests --stress-runs 48

Reviewed By: jsedgwick@fb.com

Subscribers: doug, fugalh, folly-diffs@

FB internal diff: D1769345

Tasks: 5948465

Signature: t1:1769345:1420654316:196121ca30c905497a0acade05b9d877c98f6eeb

Summary:
* folly/wangle/bootstrap/ServerBootstrap.h:
Change type of a for-loop index from int to size_t.

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: jsedgwick@fb.com

Subscribers: fugalh, folly-diffs@

FB internal diff: D1770091

Tasks: 5941250

Signature: t1:1770091:1420667597:fbe9a5ba56a0e34e0480c82c8fb61128406ded95

Summary:
The AHA-insert-race test case (a) does a LOT of iterations, and
(b) allocated and deallocates a lot of memory on each iteration.

The long iterations, by themselves, take 8s, and should be reduced.
Further, ASAN errors on these tests, since it needs to hold on to memory
for a bit of time and ends up OOMing.

Test Plan:
fbconfig -r 'folly' '--platform-all=gcc-4.8.1-glibc-2.17-fb' '--sanitize=address'
fbmake runtests Ahm.atomic_hash_array_insert_race

Reviewed By: robbert@fb.com

Subscribers: sdwilsh, folly-diffs@

FB internal diff: D1767334

Tasks: 5941888

Signature: t1:1767334:1420612386:4d6f4067b30d1cb7d20bcfeb0f31fac1339ead20

Summary:
* folly/small_vector.h (moveToUninitialized): Do not mix
signed and unsigned for-loop index/limit.  Instead, eliminate
the intermediate "count" altogether and iterate as long as
"first" is not equal to "last". Otherwise, gcc-4.9 fails with e.g.,
folly/small_vector.h:115:18: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: soren@fb.com

Subscribers: trunkagent, folly-diffs@

FB internal diff: D1767844

Tasks: 5941250

Signature: t1:1767844:1420601608:987fd7f7d44197ed9919910c9b559b37fbe421b6

Summary:
* folly/FBVector.h (make_window): Declare "tail" to be
explicitly of the same type as "n".  Otherwise, we'd
use the type of std::distance, which is unsigned, and
then compare that against "n" of type "size_type", which
is unsigned, and we'd get this from gcc-4.9:
folly/FBVector.h:1276:14: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com, andrei.alexandrescu@fb.com

Subscribers: trunkagent, njormrod, folly-diffs@

FB internal diff: D1768346

Tasks: 5941250

Signature: t1:1768346:1420594452:654dac805bb46f7c6a38b4e4102e4004720d6835

Summary:
* folly/test/RangeTest.cpp (NeedleFinderTest): Declare for-loop
index to be of type size_t.  OTherwise, gcc-4.9 fails:
folly/test/RangeTest.cpp:910:23: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: folly-diffs@

FB internal diff: D1768279

Tasks: 5941250

Signature: t1:1768279:1420593237:246040eebd40e313bdb19799bb11d6639f1481de

Summary:
* folly/experimental/test/BitsBenchmark.cpp (benchmarkSet):
Another s/int/size_t/ change to type of for-loop index, to match
the type of the loop's upper bound.

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: davejwatson@fb.com

Subscribers: folly-diffs@

FB internal diff: D1767853

Tasks: 5941250

Signature: t1:1767853:1420587945:f32a0ef33f6c5fa75598ecb114a243f83b31e550

Summary:
* folly/wangle/channel/ChannelPipeline.h: Declare for-loop indices
to be of type size_t(not int), to match size of upper bound.
Otherwise, gcc-4.9 fails with e.g.,
folly/wangle/channel/ChannelPipeline.h:126:23: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: davejwatson@fb.com

Subscribers: fugalh, folly-diffs@

FB internal diff: D1767783

Tasks: 5941250

Signature: t1:1767783:1420587925:d662b75e6a62ebd5bacdde28ad6e1da22ef777ac

Summary:
[just like https://phabricator.fb.com/D1767160 --
I don't know why I didn't see this the first time]
* folly/gen/Parallel-inl.h (folly): Use a for-loop index of type
size_t (not "int") to match type of upper bound.
Otherwise, gcc-4.9 fails with this:
folly/gen/Parallel-inl.h:242:27: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: philipp@fb.com

Subscribers: folly-diffs@

FB internal diff: D1767520

Signature: t1:1767520:1420583501:121f7212f78774adb6ca7cf67cbab83bf604cbbe

Summary:
* folly/gen/Parallel-inl.h (folly): Use a for-loop index of type
size_t (not "int") to match type of upper bound.
Otherwise, gcc-4.9 fails with this:
folly/gen/Parallel-inl.h:242:27: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 -r folly && fbmake dbgo

Reviewed By: davejwatson@fb.com

Subscribers: folly-diffs@

FB internal diff: D1767160

Tasks: 5941250

Signature: t1:1767160:1420577886:6acfb7f6d50ed715dcf4058841aeabc39fa99cbc

Summary:
- Manually swap bucket_ entries in HHWheelTimer to work around a bug in
libc++

Test Plan:
- fbconfig -r folly/io/async && fbmake runtests --extended-tests
- Sync to OS X and build there

Reviewed By: davejwatson@fb.com

Subscribers: trunkagent, doug, seanc, folly-diffs@

FB internal diff: D1766601

Signature: t1:1766601:1420566916:24a2911e997ee04f0934884bdf7b82345cb2b752

Summary:
Fixes T5922800
(I think)

Test Plan:
TBH I don't know why detaching a temporary thread variable might cause the program to abort but this seems to be the most likely cause so I'm making this change and we'll see in a day or two if it fixes it.

The test still passes and doesn't hang

Reviewed By: davejwatson@fb.com

Subscribers: fugalh, exa, folly-diffs@

FB internal diff: D1764374

Tasks: 5922800

Signature: t1:1764374:1420485233:2e4c81776ef6b6bdae18fbf2e99f0deea37b7879

Summary:
* folly/Format-inl.h (BaseFormatter): Move decls of P and END down
past the shadowed decls.  Otherwise, gcc-4.9 would emit this:
./folly/Format-inl.h:209:10: error: declaration of 'p' shadows a previous local [-Werror=shadow-local]
./folly/Format-inl.h:202:8: error: shadowed declaration is here [-Werror=shadow-local]
./folly/Format-inl.h:210:10: error: declaration of 'end' shadows a previous local [-Werror=shadow-local]
./folly/Format-inl.h:203:8: error: shadowed declaration is here [-Werror=shadow-local]

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 tao/server && fbmake dbgo

Reviewed By: andrewjcg@fb.com

Subscribers: trunkagent, net-systems@, folly-diffs@

FB internal diff: D1766673

Tasks: 5941250

Signature: t1:1766673:1420569376:22c5c3a012715e479b27ba6f0bde1a3b079a3be3

Summary: Observer methods, so users of IOThreadPoolExecutor can do stuff when threads are added/removed.  As a use case, previously the thrift server only used the threads already started when it started up, and assumed iothreadpool was never resized.

Test Plan: Added several unittests

Reviewed By: jsedgwick@fb.com

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

FB internal diff: D1753861

Signature: t1:1753861:1420236825:54cbdfee0efb3b97dea35faba29c134f2b10a480

Summary:
* folly/Range.cpp (scanHaystackBlock): This method mistakenly
declared its "idx" (aka blockStartIdx) parameter to have signed type.
It is logically an unsigned type and is compared only with other
variables of unsigned type, so make it unsigned.
Here's the diagnostic:
folly/Range.cpp:202:44: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
folly/Range.cpp: In instantiation of 'size_t folly::detail::scanHaystackBlock(folly::StringPiece, folly::StringPiece, int64_t) [with bool HAYSTACK_ALIGNED = true; size_t = long unsigned int; folly::StringPiece = folly::Range<const char*>; int64_t = long int]':

Test Plan:
Run this and note there are fewer errors than before:
fbconfig --platform-all=gcc-4.9-glibc-2.20 tao/server && fbmake dbgo

Reviewed By: robbert@fb.com, philipp@fb.com

Subscribers: folly-diffs@

FB internal diff: D1765590

Signature: t1:1765590:1420506036:7cbe2c454ad1f018a1c0aa5112a38bed1b2ac673

Summary:
see https://www.facebook.com/groups/738749156173702/permalink/798168656898418/

I suppressed "comparison between signed and unsigned integer expressions" warnings for this first pass because there a whole lot (dozens) of those. Do we suppress those with 4.8 or something? Never seen the warnings before.

I can't find anything in boost 1.57 docs/changelog indicating why implicit conversion of boost::optional<bool> -> bool doesn't compile anymore, but it doesn't.

Test Plan: fbconfig -r --platform-all gcc-4.9-glibc-2.20 --extra-cxxflags="-Wno-sign-compare" folly && fbmake opt && fbmake runtests_opt

Reviewed By: rhysparry@fb.com

Subscribers: trunkagent, fugalh, folly-diffs@

FB internal diff: D1765093

Signature: t1:1765093:1420500411:062acf841641c7f4142c9b48e8daa45327de6822

Summary:
This is a bootstrap script for building folly on osx. I attempted to make it Just Work™ for anyone who uses Homebrew (http://brew.sh/) but even if it doesn't work out of the box it should be instructive for the motivated developer on OSX.

Facebook:
In #5134151 Wangle used to not build, because something was using a futex. But that seems to have been rectified (or the build problems are hiding in headers that aren't used in the libfolly build).

I'll also update https://our.intern.facebook.com/intern/wiki/Folly/BuildingOnMac to point people to this script instead.

Test Plan:
Tested on my laptop which is running Yosemite (10.10.1)
Build, then inspect `otool -L .libs/*dylib`

Reviewed By: davejwatson@fb.com

Subscribers: folly-diffs@, exa

FB internal diff: D1765248

Tasks: 5134151

Signature: t1:1765248:1420500905:bc5da97a0446f502cb2badc85c9004ff0a62027a

Summary: another unittest that doesn't work without reuseport support, add a check

Test Plan: ran it on sandcastle187.prn2, works

Reviewed By: njormrod@fb.com

Subscribers: doug, fugalh, folly-diffs@

FB internal diff: D1764395

Tasks: 5931982

Signature: t1:1764395:1420490666:658aef148ebca9484534a0cebb228570e28f1002

Summary:
Can't connect from ipv6-only cluster to ipv4/ipv6 service which uses different ports.

Facebook:
A lot of tests start a service, get its port, and try to connect to 127.0.0.1:port, which breaks
after this diff since the port corresponds to IPv6 address, not IPv4. Fixing this by changing
127.0.0.1 to ::1 in places found by sandcastle.

```
fbconfig servicerouter/aggregator/tests servicerouter/client/cpp/test common/fb303/cpp/test thrift/lib/cpp2/test unicorn/hotswap/test common/client_mgmt thrift/test servicerouter/client/swig/tests unicorn/async/test servicerouter/selection/tests
```

Test Plan:
```
$ ./fastcopy_server --dir . &
$ netstat -atnlp | grep LISTEN | grep fastcopy
tcp        0      0 0.0.0.0:65478               0.0.0.0:*                   LISTEN      9348/./fastcopy_ser
tcp        0      0 :::52793                    :::*                        LISTEN      9348/./fastcopy_ser
```

Reviewed By: philipp@fb.com

Subscribers: trunkagent, vkatich, fbcode-common-diffs@, chaoyc, search-fbcode-diffs@, davejwatson, andrewcox, mcduff, hitesh, unicorn-diffs@, alandau, mshneer, folly-diffs@, bmatheny, ps, soren

FB internal diff: D1760372

Tasks: 5868818, 5886688

Signature: t1:1760372:1419992695:e7d254b2b8f730baefc169effa236b8daa9d846d

Summary:
De-couple TransportInfo fields from SSL session structs to avoid
dangling pointers.

Facebook:
We sometimes lazily copy TransportInfo in handler after
detachClientTransaction for logging. If the socket is closed, then this
creates dangling pointers to some SSL structs. This is an attempt to fix
that.

This is similar to what @ajitb did in
https://phabricator.fb.com/D1666951 which had to be abandoned because of
memory overhead. Here, instead of copying the relevant fields per
transaction, we are only doing it once per session (shared_ptr), so the
memory overhead should be negligible.

Test Plan: Unit tests pass. Will canary

Reviewed By: afrind@fb.com

Subscribers: fugalh, bmatheny, ssl-diffs@, folly-diffs@, ajitb

FB internal diff: D1757318

Tasks: 5865651, 5879508

Signature: t1:1757318:1420482488:9f5144b499eb2086cf2a80243328db5715b48f88

Summary: This change simplifies Singleton API (methods don't need to accept name) and the actual implementation. It also makes it similar to folly::ThreadLocalPtr. Additionally misspelled singleton name becomes compilation error, not runtime error. Some users were actually naming singletons, when that was neccessary, this should also be fixed.

Test Plan: unit tests for all touched projects

Reviewed By: chip@fb.com

Subscribers: trunkagent, fugalh, jsedgwick, fbcode-common-diffs@, mcduff, hitesh, mshneer, folly-diffs@

FB internal diff: D1744978

Signature: t1:1744978:1419282587:bd29dd8a70d7572530ac371a96a21764229bc397

Summary: `__cxa_throw` signature didn't match C++ ABI (see 2.4.3 in http://refspecs.linuxfoundation.org/abi-eh-1.22.html), gcc 4.9 was complaining.

Test Plan: fbconfig -r folly && fbmake opt -j32

Reviewed By: soren@fb.com

Subscribers: folly-diffs@

FB internal diff: D1760492

Tasks: 5908365

Signature: t1:1760492:1420251038:6d04683f96ac889ff348ca0485420c975819b90b

Summary:
Making sure Wangle can handle circular dependencies.
There was an actual code issue in September that cause a crash in Atlas
Adserver due to this. The issue has been since fixed and Adserver's code
has been changed to avoid such circular dependency. We're adding a unit
test for this case.

Unit test is added as per our conversation on the Wangle group: https://www.facebook.com/groups/715931878455430/permalink/770180369697247/

Test Plan:
Add the same test on a code base from Sep 20th, observe that it fails:
https://phabricator.fb.com/P19352007

Run the unit test on latest code base - it succeeds

Reviewed By: hans@fb.com

Subscribers: atlas2-eng@, fugalh, folly-diffs@, leizhao, mchughj, kit, mpechuk

FB internal diff: D1761006

Tasks: 5384229

Signature: t1:1761006:1420238204:74ffb3fe8b88a25a23ade8e0990e69d405ea7f1e