docs/native-code/development/README.md - src.git - Git at Google

 # WebRTC development

 The currently supported platforms are Windows, Mac OS X, Linux, Android and iOS.
 See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
 pages for build instructions and example applications specific to these mobile
 platforms.

 ## Before You Start

 First, be sure to install the [prerequisite software][webrtc-prerequisite-sw].

 ## Getting the Code

 For desktop development:

 1. Create a working directory, enter it, and run `fetch webrtc`:

 ```
 $ mkdir webrtc-checkout
 $ cd webrtc-checkout
 $ fetch --nohooks webrtc
 $ gclient sync
 ```

 NOTICE: During your first sync, you'll have to accept the license agreement of
 the Google Play Services SDK.

 The checkout size is large due the use of the Chromium build toolchain and many
 dependencies. Estimated size:

 - Linux: 6.4 GB.
 - Linux (with Android): 16 GB (of which ~8 GB is Android SDK+NDK images).
 - Mac (with iOS support): 5.6GB

 If you don't need the git history (e.g. for bots, CI or building a release),
 pass `--no-history` to `fetch` to do shallow clones of `src` and all its
 dependencies. This reduces both the checkout size and the time it takes
 significantly:

 ```
 $ fetch --nohooks --no-history webrtc
 $ gclient sync --no-history
 ```

 Note that `git log`, `git blame` and moving to older revisions won't work as
 expected in a shallow checkout.

 2. Optionally you can specify how new branches should be tracked:

 ```
 $ git config branch.autosetupmerge always
 $ git config branch.autosetuprebase always
 ```

 3. Alternatively, you can create new local branches like this (recommended):

 ```
 $ cd src
 $ git checkout main
 $ git new-branch your-branch-name
 ```

 See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
 pages for separate instructions.

 **NOTICE:** if you get `Remote: Daily bandwidth rate limit exceeded for <ip>`,
 make sure you're logged in. The quota is much larger for logged in users.

 ## Updating the Code

 Update your current branch with:

 ```
 $ git checkout main
 $ git pull origin main
 $ gclient sync
 $ git checkout my-branch
 $ git merge main
 ```

 ## Building

 [Ninja] is the default build system for all platforms.

 See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
 pages for build instructions specific to those platforms.

 ## Generating Ninja project files

 [Ninja] project files are generated using [GN]. They're put in a directory of
 your choice, like `out/Debug` or `out/Release`, but you can use any directory
 for keeping multiple configurations handy.

 To generate project files using the defaults (Debug build), run (standing in the
 src/ directory of your checkout):

 ```
 $ gn gen out/Default
 ```

 To generate ninja project files for a Release build instead:

 ```
 $ gn gen out/Default --args='is_debug=false'
 ```

 To clean all build artifacts in a directory but leave the current GN
 configuration untouched (stored in the args.gn file), do:

 ```
 $ gn clean out/Default
 ```

 To build the fuzzers residing in the [test/fuzzers][fuzzers-dir] directory, read
 the instructions at the [fuzzers] page.

 See the [GN][gn-doc] documentation for all available options. There are also
 more platform specific tips on the [Android][webrtc-android-development] and
 [iOS][webrtc-ios-development] instructions.

 ## Compiling

 When you have Ninja project files generated (see previous section), compile
 (standing in `src/`) using:

 For [Ninja] project files generated in `out/Default`:

 ```
 $ autoninja -C out/Default
 ```

 To build everything in the generated folder (`out/Default`):

 ```
 $ autoninja all -C out/Default
 ```

 `autoninja` is a wrapper that automatically provides optimal values for the
 arguments passed to `ninja`.

 See [Ninja build rules][ninja-build-rules] to read more about difference between
 `ninja` and `ninja all`.

 To build a particular target (like a fuzzer which is not included in the main
 target) use

 ```
 autoninja -C out/Default h264_depacketizer_fuzzer
 ```

 ## Using Another Build System

 Other build systems are **not supported** (and may fail), such as Visual Studio
 on Windows or Xcode on OSX. GN supports a hybrid approach of using [Ninja] for
 building, but Visual Studio/Xcode for editing and driving compilation.

 To generate IDE project files, pass the `--ide` flag to the [GN] command. See
 the [GN reference][gn-doc] for more details on the supported IDEs.

 ## Working with Release Branches

 To see available release branches, run:

 ```
 $ git branch -r
 ```

 To create a local branch tracking a remote release branch (in this example, the
 branch corresponding to Chrome M80):

 ```
 $ git checkout -b my_branch refs/remotes/branch-heads/3987
 $ gclient sync
 ```

 **NOTICE**: depot_tools are not tracked with your checkout, so it's possible
 gclient sync will break on sufficiently old branches. In that case, you can try
 using an older depot_tools:

 ```
 which gclient
 $ # cd to depot_tools dir
 $ # edit update_depot_tools; add an exit command at the top of the file
 $ git log  # find a hash close to the date when the branch happened
 $ git checkout <hash>
 $ cd ~/dev/webrtc/src
 $ gclient sync
 $ # When done, go back to depot_tools, git reset --hard, run gclient again and
 $ # verify the current branch becomes REMOTE:origin/main
 ```

 The above is untested and unsupported, but it might help.

 Commit log for the branch:
 [https://webrtc.googlesource.com/src/+log/branch-heads/3987][m80-log] To browse
 it: [https://webrtc.googlesource.com/src/+/branch-heads/3987][m80]

 For more details, read Chromium's
 [Working with Branches][chromium-work-branches] and
 [Working with Release Branches][chromium-work-release-branches] pages. To find
 the branch corresponding to a Chrome release check the
 [Chromium Dashboard][chromium-dashboard].

 ## Contributing Patches

 Please see [Contributing Fixes][contributing] for information on how to run
 `git cl upload`, getting your patch reviewed, and getting it submitted. You can
 also find info on how to run trybots and applying for try rights.

 ## Chromium Committers

 Many WebRTC committers are also Chromium committers. To make sure to use the
 right account for pushing commits to WebRTC, use the `user.email` Git config
 setting. The recommended way is to have the chromium committer account set
 globally as described at the [depot tools setup page][depot-tools] and then set
 `user.email` locally for the WebRTC repos using:

 ```
 $ cd /path/to/webrtc/src
 $ git config user.email <YOUR_WEBRTC_COMMITTER_EMAIL>
 ```

 ## Example Applications

 WebRTC contains several example applications, which can be found under
 `src/webrtc/examples`. Higher level applications are listed first.

 ### Peerconnection

 Peerconnection consist of two applications using the WebRTC Native APIs:

 - A server application, with target name `peerconnection_server`
 - A client application, with target name `peerconnection_client` (not currently
   supported on Mac/Android)

 The client application has simple voice and video capabilities. The server
 enables client applications to initiate a call between clients by managing
 signaling messages generated by the clients.

 #### Setting up P2P calls between peerconnection_clients

 Start `peerconnection_server`. You should see the following message indicating
 that it is running:

 ```
 Server listening on port 8888
 ```

 Start any number of `peerconnection_clients` and connect them to the server. The
 client UI consists of a few parts:

 **Connecting to a server:** When the application is started you must specify
 which machine (by IP address) the server application is running on. Once that is
 done you can press **Connect** or the return button.

 **Select a peer:** Once successfully connected to a server, you can connect to a
 peer by double-clicking or select+press return on a peer's name.

 **Video chat:** When a peer has been successfully connected to, a video chat
 will be displayed in full window.

 **Ending chat session:** Press **Esc**. You will now be back to selecting a
 peer.

 **Ending connection:** Press **Esc** and you will now be able to select which
 server to connect to.

 #### Testing peerconnection_server

 Start an instance of `peerconnection_server` application.

 Open `src/webrtc/examples/peerconnection/server/server_test.html` in your
 browser. Click **Connect**. Observe that the `peerconnection_server` announces
 your connection. Open one more tab using the same page. Connect it too (with a
 different name). It is now possible to exchange messages between the connected
 peers.

 ### STUN Server

 Target name `stunserver`. Implements the STUN protocol for Session Traversal
 Utilities for NAT as documented in [RFC 5389][rfc-5389].

 ### TURN Server

 Target name `turnserver`. Used for unit tests.

 [chromium-dashboard]: https://chromiumdash.appspot.com/branches
 [chromium-work-branches]: https://www.chromium.org/developers/how-tos/get-the-code/working-with-branches
 [chromium-work-release-branches]: https://www.chromium.org/developers/how-tos/get-the-code/working-with-release-branches
 [contributing]: https://webrtc.googlesource.com/src/+/refs/heads/main/docs/native-code/development/contributing.md
 [depot-tools]: http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up
 [fuzzers]: https://webrtc.googlesource.com/src/+/main/docs/native-code/development/fuzzers/
 [fuzzers-dir]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/
 [gn]: https://gn.googlesource.com/gn/+/main/README.md
 [gn-doc]: https://gn.googlesource.com/gn/+/main/docs/reference.md#IDE-options
 [m80]: https://webrtc.googlesource.com/src/+/branch-heads/3987
 [m80-log]: https://webrtc.googlesource.com/src/+log/branch-heads/3987
 [ninja]: https://ninja-build.org/
 [ninja-build-rules]: https://gn.googlesource.com/gn/+/main/docs/reference.md#the-all-and-default-rules
 [rfc-5389]: https://tools.ietf.org/html/rfc5389
 [webrtc-android-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/android/
 [webrtc-ios-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/ios/
 [webrtc-prerequisite-sw]: https://webrtc.googlesource.com/src/+/main/docs/native-code/development/prerequisite-sw/
	# WebRTC development

	The currently supported platforms are Windows, Mac OS X, Linux, Android and iOS.
	See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
	pages for build instructions and example applications specific to these mobile
	platforms.

	## Before You Start

	First, be sure to install the [prerequisite software][webrtc-prerequisite-sw].

	## Getting the Code

	For desktop development:

	1. Create a working directory, enter it, and run `fetch webrtc`:

	```
	$ mkdir webrtc-checkout
	$ cd webrtc-checkout
	$ fetch --nohooks webrtc
	$ gclient sync
	```

	NOTICE: During your first sync, you'll have to accept the license agreement of
	the Google Play Services SDK.

	The checkout size is large due the use of the Chromium build toolchain and many
	dependencies. Estimated size:

	- Linux: 6.4 GB.
	- Linux (with Android): 16 GB (of which ~8 GB is Android SDK+NDK images).
	- Mac (with iOS support): 5.6GB

	If you don't need the git history (e.g. for bots, CI or building a release),
	pass `--no-history` to `fetch` to do shallow clones of `src` and all its
	dependencies. This reduces both the checkout size and the time it takes
	significantly:

	```
	$ fetch --nohooks --no-history webrtc
	$ gclient sync --no-history
	```

	Note that `git log`, `git blame` and moving to older revisions won't work as
	expected in a shallow checkout.

	2. Optionally you can specify how new branches should be tracked:

	```
	$ git config branch.autosetupmerge always
	$ git config branch.autosetuprebase always
	```

	3. Alternatively, you can create new local branches like this (recommended):

	```
	$ cd src
	$ git checkout main
	$ git new-branch your-branch-name
	```

	See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
	pages for separate instructions.

	NOTICE: if you get `Remote: Daily bandwidth rate limit exceeded for <ip>`,
	make sure you're logged in. The quota is much larger for logged in users.

	## Updating the Code

	Update your current branch with:

	```
	$ git checkout main
	$ git pull origin main
	$ gclient sync
	$ git checkout my-branch
	$ git merge main
	```

	## Building

	[Ninja] is the default build system for all platforms.

	See the [Android][webrtc-android-development] and [iOS][webrtc-ios-development]
	pages for build instructions specific to those platforms.

	## Generating Ninja project files

	[Ninja] project files are generated using [GN]. They're put in a directory of
	your choice, like `out/Debug` or `out/Release`, but you can use any directory
	for keeping multiple configurations handy.

	To generate project files using the defaults (Debug build), run (standing in the
	src/ directory of your checkout):

	```
	$ gn gen out/Default
	```

	To generate ninja project files for a Release build instead:

	```
	$ gn gen out/Default --args='is_debug=false'
	```

	To clean all build artifacts in a directory but leave the current GN
	configuration untouched (stored in the args.gn file), do:

	```
	$ gn clean out/Default
	```

	To build the fuzzers residing in the [test/fuzzers][fuzzers-dir] directory, read
	the instructions at the [fuzzers] page.

	See the [GN][gn-doc] documentation for all available options. There are also
	more platform specific tips on the [Android][webrtc-android-development] and
	[iOS][webrtc-ios-development] instructions.

	## Compiling

	When you have Ninja project files generated (see previous section), compile
	(standing in `src/`) using:

	For [Ninja] project files generated in `out/Default`:

	```
	$ autoninja -C out/Default
	```

	To build everything in the generated folder (`out/Default`):

	```
	$ autoninja all -C out/Default
	```

	`autoninja` is a wrapper that automatically provides optimal values for the
	arguments passed to `ninja`.

	See [Ninja build rules][ninja-build-rules] to read more about difference between
	`ninja` and `ninja all`.

	To build a particular target (like a fuzzer which is not included in the main
	target) use

	```
	autoninja -C out/Default h264_depacketizer_fuzzer
	```

	## Using Another Build System

	Other build systems are not supported (and may fail), such as Visual Studio
	on Windows or Xcode on OSX. GN supports a hybrid approach of using [Ninja] for
	building, but Visual Studio/Xcode for editing and driving compilation.

	To generate IDE project files, pass the `--ide` flag to the [GN] command. See
	the [GN reference][gn-doc] for more details on the supported IDEs.

	## Working with Release Branches

	To see available release branches, run:

	```
	$ git branch -r
	```

	To create a local branch tracking a remote release branch (in this example, the
	branch corresponding to Chrome M80):

	```
	$ git checkout -b my_branch refs/remotes/branch-heads/3987
	$ gclient sync
	```

	NOTICE: depot_tools are not tracked with your checkout, so it's possible
	gclient sync will break on sufficiently old branches. In that case, you can try
	using an older depot_tools:

	```
	which gclient
	$ # cd to depot_tools dir
	$ # edit update_depot_tools; add an exit command at the top of the file
	$ git log # find a hash close to the date when the branch happened
	$ git checkout <hash>
	$ cd ~/dev/webrtc/src
	$ gclient sync
	$ # When done, go back to depot_tools, git reset --hard, run gclient again and
	$ # verify the current branch becomes REMOTE:origin/main
	```

	The above is untested and unsupported, but it might help.

	Commit log for the branch:
	[https://webrtc.googlesource.com/src/+log/branch-heads/3987][m80-log] To browse
	it: [https://webrtc.googlesource.com/src/+/branch-heads/3987][m80]

	For more details, read Chromium's
	[Working with Branches][chromium-work-branches] and
	[Working with Release Branches][chromium-work-release-branches] pages. To find
	the branch corresponding to a Chrome release check the
	[Chromium Dashboard][chromium-dashboard].

	## Contributing Patches

	Please see [Contributing Fixes][contributing] for information on how to run
	`git cl upload`, getting your patch reviewed, and getting it submitted. You can
	also find info on how to run trybots and applying for try rights.

	## Chromium Committers

	Many WebRTC committers are also Chromium committers. To make sure to use the
	right account for pushing commits to WebRTC, use the `user.email` Git config
	setting. The recommended way is to have the chromium committer account set
	globally as described at the [depot tools setup page][depot-tools] and then set
	`user.email` locally for the WebRTC repos using:

	```
	$ cd /path/to/webrtc/src
	$ git config user.email <YOUR_WEBRTC_COMMITTER_EMAIL>
	```

	## Example Applications

	WebRTC contains several example applications, which can be found under
	`src/webrtc/examples`. Higher level applications are listed first.

	### Peerconnection

	Peerconnection consist of two applications using the WebRTC Native APIs:

	- A server application, with target name `peerconnection_server`
	- A client application, with target name `peerconnection_client` (not currently
	supported on Mac/Android)

	The client application has simple voice and video capabilities. The server
	enables client applications to initiate a call between clients by managing
	signaling messages generated by the clients.

	#### Setting up P2P calls between peerconnection_clients

	Start `peerconnection_server`. You should see the following message indicating
	that it is running:

	```
	Server listening on port 8888
	```

	Start any number of `peerconnection_clients` and connect them to the server. The
	client UI consists of a few parts:

	Connecting to a server: When the application is started you must specify
	which machine (by IP address) the server application is running on. Once that is
	done you can press Connect or the return button.

	Select a peer: Once successfully connected to a server, you can connect to a
	peer by double-clicking or select+press return on a peer's name.

	Video chat: When a peer has been successfully connected to, a video chat
	will be displayed in full window.

	Ending chat session: Press Esc. You will now be back to selecting a
	peer.

	Ending connection: Press Esc and you will now be able to select which
	server to connect to.

	#### Testing peerconnection_server

	Start an instance of `peerconnection_server` application.

	Open `src/webrtc/examples/peerconnection/server/server_test.html` in your
	browser. Click Connect. Observe that the `peerconnection_server` announces
	your connection. Open one more tab using the same page. Connect it too (with a
	different name). It is now possible to exchange messages between the connected
	peers.

	### STUN Server

	Target name `stunserver`. Implements the STUN protocol for Session Traversal
	Utilities for NAT as documented in [RFC 5389][rfc-5389].

	### TURN Server

	Target name `turnserver`. Used for unit tests.

	[chromium-dashboard]: https://chromiumdash.appspot.com/branches
	[chromium-work-branches]: https://www.chromium.org/developers/how-tos/get-the-code/working-with-branches
	[chromium-work-release-branches]: https://www.chromium.org/developers/how-tos/get-the-code/working-with-release-branches
	[contributing]: https://webrtc.googlesource.com/src/+/refs/heads/main/docs/native-code/development/contributing.md
	[depot-tools]: http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up
	[fuzzers]: https://webrtc.googlesource.com/src/+/main/docs/native-code/development/fuzzers/
	[fuzzers-dir]: https://webrtc.googlesource.com/src/+/main/test/fuzzers/
	[gn]: https://gn.googlesource.com/gn/+/main/README.md
	[gn-doc]: https://gn.googlesource.com/gn/+/main/docs/reference.md#IDE-options
	[m80]: https://webrtc.googlesource.com/src/+/branch-heads/3987
	[m80-log]: https://webrtc.googlesource.com/src/+log/branch-heads/3987
	[ninja]: https://ninja-build.org/
	[ninja-build-rules]: https://gn.googlesource.com/gn/+/main/docs/reference.md#the-all-and-default-rules
	[rfc-5389]: https://tools.ietf.org/html/rfc5389
	[webrtc-android-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/android/
	[webrtc-ios-development]: https://webrtc.googlesource.com/src/+/main/docs/native-code/ios/
	[webrtc-prerequisite-sw]: https://webrtc.googlesource.com/src/+/main/docs/native-code/development/prerequisite-sw/