webports

webports is collection of open source libraries and applications that have been ported to Native Client, along with set to tools for building and maintaining them.

Packages can be built from source or prebuilt binaries packages can be downloaded from the continuous build system.

The sources for the ports live in the ports directory. Each one contains at least the following file:

pkg_info: a description of the package.

Most also contain the follow optional files:

build.sh: a bash script for building it
nacl.patch: an optional patch file.

The tools for building packages live in bin. The binary tool is simple called webports. To build and install a package into the toolchain run webports install <package_dir>. This script will download, patch, build and install the application or library. By default it will first install any dependencies that that the package has.

Prerequistes

The minimum requirements for using webports are:

python 2.7
python-dev
gclient (from depot_tools)
Native Client SDK

For building packages from source the build scripts require that certain tools are present in the host system:

bash
make
curl
sed
git

To build all ports you will also need these:

cmake
texinfo
gettext
pkg-config
autoconf, automake, libtool
libglib2.0-dev >= 2.26.0 (if you want to build glib)
xsltproc

On Mac OS X you can use homebrew to install these using the following command:

$ brew install autoconf automake cmake gettext libtool pkg-config

The build system for some of the native Python modules relies on a 32-bit host build of Python itself, which in turn relies on the development version of zlib and libssl being available. On 64-bit Ubuntu/Trusty this means installing:

zlib1g-dev:i386
libssl-dev:i386

On older Debian/Ubuntu systems these packages were known as:

lib32z1-dev
libssl1.0.0:i386

The following 32-bit packages are also needed in order to run some of the 32-bit binaries in the NaCl SDK:

libstdc++6:i386
libglib2.0-0:i386

How to Checkout

Although the code is stored in git webports uses gclient to manage the checkout of dependencies. You will need to install depot_tools in order to use gclient.

Use the following steps to correctly checkout webports:

Create a directory:

$ mkdir webports
$ cd webports

Create a .gclient Configuration:

$ gclient config --unmanaged --name=src \
    https://chromium.googlesource.com/webports.git

Sync the code and dependencies:

$ gclient sync --with_branch_heads

Optionally Checkout the relevant branch. The master branch is designed to be used with pepper_canary. For older SDK versions switch the corresponding pepper_XX branch, e.g:

$ cd src
$ git checkout -b pepper_49 origin/pepper_49
$ gclient sync

Building

Before you can build any of the package you must set the NACL_SDK_ROOT environment variable to top directory of a version of the Native Client SDK (the directory containing toolchain/). This path should be absolute.

The top level Makefile can be used as a quick way to build one or more packages. For example, make libvorbis will build libvorbis and libogg. make all will build all the packages.

There are 4 possible architectures that NaCl modules can be compiled for: i686, x86_64, arm, pnacl. The webports build system will only build just one at at time. You can control which one by setting the NACL_ARCH environment variable. e.g.:

$ cd src
$ NACL_ARCH=arm make openssl

For some architectures there is more than one toolchain available. For example for x86 you can choose between clang-newlib and glibc. The toolchain defaults to pnacl and can be specified by setting the TOOLCHAIN environment variable:

$ NACL_ARCH=i686 TOOLCHAIN=glibc make openssl

If you want to build a certain package for all architectures and all toolchains you can use the top level make_all.sh script. e.g.:

$ ./make_all.sh openssl

Headers and libraries are installed into the toolchains directly so there is not add extra -I or -L options in order to use the libraries.

The source code and build output for each package is placed in:

out/build/<PACKAGE_NAME>

By default all builds are in release configuration. If you want to build debug packages set NACL_DEBUG=1 or pass --debug to the webports script.

Note: Each package has its own license. Please read and understand these licenses before using these packages in your projects.

Note to Windows users: These scripts are written in bash and must be launched from a Cygwin shell. While many of the scripts should work under Cygwin, webports is only tested on Linux and Mac so YMMV.

Binary Packages

By default webports will attempt to install binary packages rather than building them from source. The binary packages are produced by the buildbots and stored in Google cloud storage. The index of current binary packages is stored in lib/prebuilt.txt and this is currently manually updated by running build_tools/scan_packages.py.

If the package version does not match the package will always be built from source.

If you want to force a package to be built from source you can pass --from-source to the webports script, or specify FROM_SOURCE=1 on the make command line.

Emscripten Support

The build system contains very early alpha support for building packages with Emscripten. To do requires the Emscripten SDK to be installed and configured (with the Emscripten tools in the PATH). To build for Emscripten build with TOOLCHAIN=emscripten.

Running the examples

Applications/Examples that build runnable web pages are published to out/publish. To run them in chrome you need to serve them with a web server. The easiest way to do this is to run:

$ make run

This will start a local web server serving the content of out/publish after which you can navigate to http://localhost:5103 to view the content.

Happy porting!

newtalk/webports