Latest 2016.09.26.00
Homepage https://github.com/facebook/folly
License Apache License, Version 2.0
Platforms ios 8.0, tvos 9.2
Dependencies boost-for-react-native, DoubleConversion, glog

Folly: Facebook Open-source Library

Build Status

What is folly?

Folly (acronymed loosely after Facebook Open Source Library) is a
library of C++11 components designed with practicality and efficiency
in mind. Folly contains a variety of core library components used extensively
at Facebook
. In particular, it’s often a dependency of Facebook’s other
open source C++ efforts and place where those projects can share code.

It complements (as opposed to competing against) offerings
such as Boost and of course std. In fact, we embark on defining our
own component only when something we need is either not available, or
does not meet the needed performance profile. We endeavor to remove
things from folly if or when std or Boost obsoletes them.

Performance concerns permeate much of Folly, sometimes leading to
designs that are more idiosyncratic than they would otherwise be (see
e.g. PackedSyncPtr.h, SmallLocks.h). Good performance at large
scale is a unifying theme in all of Folly.

Logical Design

Folly is a collection of relatively independent components, some as
simple as a few symbols. There is no restriction on internal
dependencies, meaning that a given folly module may use any other
folly components.

All symbols are defined in the top-level namespace folly, except of
course macros. Macro names are ALLUPPERCASE and should be prefixed
with `FOLLY
. Namespacefollydefines other internal namespaces such asinternalordetail`. User code should not depend on symbols
in those namespaces.

Folly has an experimental directory as well. This designation connotes
primarily that we feel the API may change heavily over time. This code,
typically, is still in heavy use and is well tested.

Physical Design

At the top level Folly uses the classic "stuttering" scheme
folly/folly used by Boost and others. The first directory serves as
an installation root of the library (with possible versioning a la
folly-1.0/), and the second is to distinguish the library when
including files, e.g. #include <folly/FBString.h>.

The directory structure is flat (mimicking the namespace structure),
i.e. we don’t have an elaborate directory hierarchy (it is possible
this will change in future versions). The subdirectory experimental
contains files that are used inside folly and possibly at Facebook but
not considered stable enough for client use. Your code should not use
files in folly/experimental lest it may break when you update Folly.

The folly/folly/test subdirectory includes the unittests for all
components, usually named ComponentXyzTest.cpp for each
ComponentXyz.*. The folly/folly/docs directory contains
documentation.

What’s in it?

Because of folly’s fairly flat structure, the best way to see what’s in it
is to look at the headers in top level folly/ directory. You can also
check the docs folder for documentation, starting with the
overview.

Folly is published on Github at https://github.com/facebook/folly

Build Notes

Dependencies

folly requires gcc 4.9+ and a version of boost compiled with C++14 support.

googletest is required to build and run folly’s tests. You can download
it from https://github.com/google/googletest/archive/release-1.8.0.tar.gz
The following commands can be used to download and install it:

wget https://github.com/google/googletest/archive/release-1.8.0.tar.gz && 
tar zxf release-1.8.0.tar.gz && 
rm -f release-1.8.0.tar.gz && 
cd googletest-release-1.8.0 && 
cmake configure . && 
make && 
make install

Finding dependencies in non-default locations

If you have boost, gtest, or other dependencies installed in a non-default
location, you can use the CMAKE_INCLUDE_PATH and CMAKE_LIBRARY_PATH
variables to make CMAKE look also look for header files and libraries in
non-standard locations. For example, to also search the directories
/alt/include/path1 and /alt/include/path2 for header files and the
directories /alt/lib/path1 and /alt/lib/path2 for libraries, you can invoke
cmake configure as follows:

cmake configure 
  -DCMAKE_INCLUDE_PATH=/alt/include/path1:/alt/include/path2 
  -DCMAKE_LIBRARY_PATH=/alt/lib/path1:/alt/lib/path2

Ubuntu 16.04 LTS

The following packages are required (feel free to cut and paste the apt-get
command below):

sudo apt-get install 
    g++ 
    cmake 
    libboost-all-dev 
    libevent-dev 
    libdouble-conversion-dev 
    libgoogle-glog-dev 
    libgflags-dev 
    libiberty-dev 
    liblz4-dev 
    liblzma-dev 
    libsnappy-dev 
    make 
    zlib1g-dev 
    binutils-dev 
    libjemalloc-dev 
    libssl-dev 
    pkg-config

If advanced debugging functionality is required

sudo apt-get install 
    libunwind8-dev 
    libelf-dev 
    libdwarf-dev

In the folly directory, run:

  mkdir _build && cd _build
  cmake configure ..
  make -j $(nproc)
  make install

OS X (Homebrew)

folly is available as a Formula and releases may be built via brew install folly.

You may also use folly/build/bootstrap-osx-homebrew.sh to build against master:

  cd folly
  ./build/bootstrap-osx-homebrew.sh

OS X (MacPorts)

Install the required packages from MacPorts:

  sudo port install 
    autoconf 
    automake 
    boost 
    gflags 
    git 
    google-glog 
    libevent 
    libtool 
    lz4 
    lzma 
    scons 
    snappy 
    zlib

Download and install double-conversion:

  git clone https://github.com/google/double-conversion.git
  cd double-conversion
  cmake -DBUILD_SHARED_LIBS=ON .
  make
  sudo make install

Download and install folly with the parameters listed below:

  git clone https://github.com/facebook/folly.git
  cd folly/folly
  autoreconf -ivf
  ./configure CPPFLAGS="-I/opt/local/include" LDFLAGS="-L/opt/local/lib"
  make
  sudo make install

Windows (Vcpkg)

folly is available in Vcpkg and releases may be built via vcpkg install folly:x64-windows.

You may also use vcpkg install folly:x64-windows --head to build against master.

Other Linux distributions

  • double-conversion (https://github.com/google/double-conversion)

    Download and build double-conversion.
    You may need to tell cmake where to find it.

    [double-conversion/] ln -s src double-conversion

    [folly/] mkdir build && cd build
    [folly/build/] cmake configure "-DCMAKE_INCLUDE_PATH=$DOUBLE_CONVERSION_HOME/include" "-DCMAKE_LIBRARY_PATH=$DOUBLE_CONVERSION_HOME/lib" ..

    [folly/build/] make

  • additional platform specific dependencies:

    Fedora 21 64-bit

    • gcc
    • gcc-c++
    • cmake
    • automake
    • boost-devel
    • libtool
    • lz4-devel
    • lzma-devel
    • snappy-devel
    • zlib-devel
    • glog-devel
    • gflags-devel
    • scons
    • double-conversion-devel
    • openssl-devel
    • libevent-devel

    Optional

    • libdwarf-dev
    • libelf-dev
    • libunwind8-dev

Latest podspec

{
    "name": "Folly",
    "version": "2016.09.26.00",
    "license": {
        "type": "Apache License, Version 2.0"
    },
    "homepage": "https://github.com/facebook/folly",
    "summary": "An open-source C++ library developed and used at Facebook.",
    "authors": "Facebook",
    "source": {
        "git": "https://github.com/facebook/folly.git",
        "tag": "v2016.09.26.00"
    },
    "module_name": "folly",
    "dependencies": {
        "boost-for-react-native": [],
        "DoubleConversion": [],
        "glog": []
    },
    "compiler_flags": "-DFOLLY_NO_CONFIG -DFOLLY_MOBILE=1 -DFOLLY_USE_LIBCPP=1",
    "source_files": [
        "folly/Bits.cpp",
        "folly/Conv.cpp",
        "folly/Demangle.cpp",
        "folly/StringBase.cpp",
        "folly/Unicode.cpp",
        "folly/dynamic.cpp",
        "folly/json.cpp",
        "folly/portability/BitsFunctexcept.cpp",
        "folly/detail/MallocImpl.cpp"
    ],
    "preserve_paths": [
        "folly/*.h",
        "folly/detail/*.h",
        "folly/portability/*.h"
    ],
    "libraries": "stdc++",
    "pod_target_xcconfig": {
        "USE_HEADERMAP": "NO",
        "CLANG_CXX_LANGUAGE_STANDARD": "c++14",
        "HEADER_SEARCH_PATHS": ""$(PODS_TARGET_SRCROOT)" "$(PODS_ROOT)/boost-for-react-native" "$(PODS_ROOT)/DoubleConversion""
    },
    "platforms": {
        "ios": "8.0",
        "tvos": "9.2"
    }
}

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