BUILDING.md

Building WebRTC

A prebuilt version of WebRTC.framework resides in the Signal Carthage submodule However, if you'd like to build it from source, with our modifications see below.

These instructions are derived from the WebRTC documentation:

https://webrtc.org/native-code/ios/

Initial Setup for first time building WebRTC.framework

Installation prerequisites

Apple Dev Tools

Note currently building WebRTC requires Xcode9+

Install depot tools

cd <somewhere>
git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
cd depot_tools
export PATH=<somewhere>/depot_tools:"$PATH"

Fetch WebRTC source

git clone https://github.com/signalapp/signal-webrtc-ios
cd signal-webrtc-ios

# Fetch the webrtc src root plus our shared patches
git submodule update --init

# Install webrtc submodules specified in DEPS
cd webrtc
gclient sync

# This process dirties the working directory. If this is your first build,
# you can skip this step. Otherwise we want to make sure we start from a
# pristine webrtc dir.
../bin/clean_webrtc.py

Updating WebRTC.framework (optional)

This section is only required if you want to use a newer version. based on: https://www.chromium.org/developers/how-tos/get-the-code/working-with-release-branches

# Make sure you are in 'signal-webrtc-ios/webrtc/src'.

# The first time your run this might take a while because it fetches
# an extra 1/2 GB or so of branch commits.
gclient sync --with_branch_heads

# OPTIONAL: If that failed, try repeating after running fetch
git fetch
gclient sync --with_branch_heads

# List available branch heads
git branch -a

# Checkout the branch 'src' tree.
# You can find a list of release notes here: https://webrtc.org/release-notes/
git checkout branch-heads/$LATEST_STABLE_RELEASE_NUMBER

# Checkout all the submodules at their branch DEPS revisions.
gclient sync --jobs 16

# Clean up anything that's since been removed from upstream.
git clean -df

Building WebRTC.framework

Finally. Why we're all here.

# Apply Signal Patches
../../bin/apply_signal_patches

# the webrtc project includes a script to build a fat framework for arm/arm64/i386/x86_64
# NOTE: the i386 build is currently broken, so you can't run iPhone5 simulators
tools_webrtc/ios/build_ios_libs.sh

# If you get errors about missing build tools, like 'gn', you may be
# able to install them with the following (then go back to "Building
# WebRTC.framework" step:
gclient runhooks

Integrate into Signal

# Remove the existing directory to make sure any obsolete files are removed
rm -r $SIGNAL_IOS_REPO_ROOT/ThirdParty/WebRTC/Build/WebRTC.framework

# Move the WebRTC.framework into Signal-iOS's WebRTC directory.
# This is a submodule to keep the size of the primary Signal-iOS repository down, 
mv out_ios_libs/WebRTC.framework $SIGNAL_IOS_REPO_ROOT/ThirdParty/WebRTC/Build/

# Make sure we add any new files, since we gitignore *
cd $SIGNAL_IOS_REPO_ROOT/ThirdParty/WebRTC/Build
git add -f WebRTC.framework
git commit -m "update artifact to <Version> (e.g. M72)"