| Mojo | 
 | ==== | 
 |  | 
 | Mojo is an effort to extract a common platform out of Chrome's renderer and | 
 | plugin processes that can support multiple types of sandboxed content, such as | 
 | HTML, Pepper, or NaCl. | 
 |  | 
 | ## Set-up and code check-out | 
 |  | 
 | The instructions below only need to be done once. Note that a simple "git clone" | 
 | command is not sufficient to build the source code because this repo uses the | 
 | gclient command from depot_tools to manage most third party dependencies. | 
 |  | 
 | 1. [Download | 
 |    depot_tools](http://www.chromium.org/developers/how-tos/install-depot-tools) | 
 |    and make sure it is in your path. | 
 | 2. [Googlers only] Install Goma in ~/goma. | 
 | 3. Create a directory somewhere for your checkout (preferably on an SSD), cd | 
 |    into it, and run the following commands: | 
 |  | 
 |  | 
 | ``` | 
 | $ fetch mojo # append --target_os=android to include Android build support. | 
 | $ cd src | 
 |  | 
 | # Or install-build-deps-android.sh if you plan to build for Android. | 
 | $ ./build/install-build-deps.sh | 
 |  | 
 | $ mojo/tools/mojob.py gn | 
 | ``` | 
 |  | 
 | The `fetch mojo` command does the following: | 
 | - creates a directory called 'src' under your checkout directory | 
 | - clones the repository using git clone | 
 | - clones dependencies with gclient sync | 
 |  | 
 | `install-build-deps.sh` installs any packages needed to build, then | 
 | `mojo/tools/mojob.py gn` runs `gn args` and configures the build directory, | 
 | out/Debug. | 
 |  | 
 | If the fetch command fails, you will need to delete the src directory and start | 
 | over. | 
 |  | 
 | ### <a name="configure-android"></a>Adding Android bits in an existing checkout | 
 |  | 
 | If you configured your set-up for Linux and now wish to build for Android, edit | 
 | the `.gclient` file in your root Mojo directory (the parent directory to src.) | 
 | and add this line at the end of the file: | 
 |  | 
 | ``` | 
 | target_os = [u'android',u'linux'] | 
 | ``` | 
 |  | 
 | Bring in Android-specific build dependencies: | 
 | ``` | 
 | $ build/install-build-deps-android.sh  | 
 | ``` | 
 |  | 
 | Pull down all of the packages with this command: | 
 | ``` | 
 | $ gclient sync | 
 | ``` | 
 |  | 
 | ## <a name="buildmojo"></a>Build Mojo | 
 |  | 
 | ### Linux | 
 |  | 
 | Build Mojo for Linux by running: | 
 |  | 
 | ``` | 
 | $ ninja -C out/Debug -j 10 | 
 | ``` | 
 |  | 
 | You can also use the `mojob.py` script for building. This script automatically | 
 | calls ninja and sets -j to an appropriate value based on whether Goma (see the | 
 | section on Goma below) is present. You cannot specify a target name with this | 
 | script. | 
 |  | 
 | ``` | 
 | mojo/tools/mojob.py gn | 
 | mojo/tools/mojob.py build | 
 | ``` | 
 |  | 
 | Run a demo: | 
 | ``` | 
 | out/Debug/mojo_shell mojo:spinning_cube | 
 | ``` | 
 |  | 
 | Run the tests: | 
 | ``` | 
 | mojo/tools/mojob.py test | 
 | ``` | 
 |  | 
 | Create a release build: | 
 | ``` | 
 | mojo/tools/mojob.py gn --release | 
 | mojo/tools/mojob.py build --release | 
 | mojo/tools/mojob.py test --release | 
 | ``` | 
 |  | 
 | ### Android | 
 |  | 
 | To build for Android, first make sure that your checkout is [configured](#configure-android) to build | 
 | for Android. After that you can use the mojob script as follows: | 
 | ``` | 
 | $ mojo/tools/mojob.py gn --android | 
 | $ mojo/tools/mojob.py build --android | 
 | ``` | 
 |  | 
 | The result will be in out/android_Debug. If you see javac compile errors, | 
 | [make sure you have an up-to-date JDK](https://code.google.com/p/chromium/wiki/AndroidBuildInstructions#Install_Java_JDK) | 
 |  | 
 | ### Goma (Googlers only) | 
 |  | 
 | If you're a Googler, you can use Goma, a distributed compiler service for | 
 | open-source projects such as Chrome and Android. If Goma is installed in the | 
 | default location (~/goma), it will work out-of-the-box with the `mojob.py gn`, | 
 | `mojob.py build` workflow described above. | 
 |  | 
 | You can also manually add: | 
 | ``` | 
 | use_goma = true | 
 | ``` | 
 |  | 
 | at the end of the file opened through: | 
 | ``` | 
 | $ gn args out/Debug | 
 | ``` | 
 |  | 
 | After you close the editor `gn gen out/Debug` will run automatically. Now you | 
 | can dramatically increase the number of parallel tasks: | 
 | ``` | 
 | $ ninja -C out/Debug -j 1000 | 
 | ``` | 
 |  | 
 | ### Official builds | 
 |  | 
 | Official builds for android generate a signed Mojo Shell intended for | 
 | distribution. You normally should not need to produce one. If you have any | 
 | questions, reach out to [etiennej@chromium.org](mailto:etiennej@chromium.org). | 
 |  | 
 | ## Update your checkout | 
 |  | 
 | You can update your checkout like this. The order is important. You must do the | 
 | `git pull` first because `gclient sync` is dependent on the current revision. | 
 | ``` | 
 | # Fetch changes from upstream and rebase the current branch on top | 
 | $ git pull --rebase | 
 | # Update all modules as directed by the DEPS file | 
 | $ gclient sync | 
 | ``` | 
 |  | 
 | You do not need to rerun `gn gen out/Debug` - ninja does so automatically each | 
 | time you build. You might need to rerun `mojo/tools/mojob.py gn` if the GN | 
 | flags have changed. | 
 |  | 
 | ## Run Mojo Shell | 
 |  | 
 | Devtools `mojo_run` is a universal shell runner abstracting away the differences | 
 | between running on Linux and Android. | 
 |  | 
 | Having built Mojo as described above, a demo app can be run as follows: | 
 |  | 
 | ``` | 
 | mojo/devtools/common/mojo_run https://core.mojoapps.io/spinning_cube.mojo  # Linux | 
 | mojo/devtools/common/mojo_run https://core.mojoapps.io/spinning_cube.mojo --android  # Android | 
 | ``` | 
 |  | 
 | ### Development server | 
 |  | 
 | Whenever `mojo_run` is run, a development server is set up according to [the | 
 | config file](mojoconfig). The server runs on your machine, serving the locally | 
 | built apps, but appears to the shell under the `https://core.mojoapps.io` host. | 
 |  | 
 | You can ignore the config file and skip spawning the local server (for example, | 
 | in order to use apps at the actual https://core.mojoapps.io web host) by passing | 
 | `--no-config-file` to `mojo_run`. | 
 |  | 
 | ### More examples | 
 |  | 
 | Some applications can be run directly from the source tree. The development | 
 | server serves the `src` directory, allowing to refer to these apps. For | 
 | instance, this command serves a dart Mojo app from the source at | 
 | `examples/dart/device_info/main.dart`: | 
 |  | 
 | ```sh | 
 | mojo_run https://core.mojoapps.io/examples/dart/device_info/main.dart [--android] | 
 | ``` | 
 |  | 
 | Some applications are meant to be run embedded in a **window manager**. To run | 
 | these, you can pass the app url using the `--embed` flag. This will run the | 
 | window manager and pass the given url to it: | 
 |  | 
 | ```sh | 
 | devtools/common/mojo_run --embed https://core.mojoapps.io/ganesh_app.mojo [--android] | 
 | ``` | 
 |  | 
 | By default, `mojo_run` uses https://core.mojoapps.io/kiosk_wm.mojo as the window | 
 | manager. You can pass a different window manager url using the | 
 | `--window-manager` flag to override this. | 
 |  | 
 | For additional information on `mojo_run` refer to the built-in help and the | 
 | [documentation](https://github.com/domokit/devtools/blob/master/README.md#runner). | 
 | You can also request more information on what the tool is doing for you by | 
 | passing the `--verbose` flag. | 
 |  | 
 | ### <a name="debugging"></a>Debugging, tracing, profiling | 
 |  | 
 | Devtools `mojo_debug` allows you to interactively inspect a running shell, | 
 | collect performance traces and attach a gdb debugger. | 
 |  | 
 | For additional information refer to the built-in help and the | 
 | [documentation](https://github.com/domokit/devtools/blob/master/README.md#debugger). | 
 |  | 
 | ### Android set-up | 
 |  | 
 | #### Adb | 
 |  | 
 | For the Android tooling to work, you will need to have `adb` in your PATH. For | 
 | that, you can either run: | 
 | ``` | 
 | source build/android/envsetup.sh | 
 | ``` | 
 |  | 
 | each time you open a fresh terminal, or add something like: | 
 | ``` | 
 | export PATH="$PATH":$MOJO_DIR/src/third_party/android_tools/sdk/platform-tools | 
 | ``` | 
 |  | 
 | to your ~/.bashrc file, $MOJO_DIR being a path to your Mojo checkout. | 
 |  | 
 | #### Device | 
 |  | 
 | **The device has to be running Android 5.0 (Lollipop) or newer.** | 
 |  | 
 | Many features useful for development (ie. streaming of the shell stdout when | 
 | running shell on the device) will not work unless the device is rooted and | 
 | running a userdebug build. For Googlers, [follow the instructions at this | 
 | link](http://go/mojo-internal-build-instructions). | 
 |  | 
 | ### Running manually on Linux | 
 |  | 
 | If you wish to, you can also run the Linux Mojo shell directly with no wrappers: | 
 | ``` | 
 | ./out/Debug/mojo_shell out/Debug/spinning_cube.mojo | 
 | ``` | 
 |  | 
 | ## Contribute | 
 |  | 
 | With git you should make all your changes in a local branch. Once your change is | 
 | committed, you can delete this branch. | 
 |  | 
 | Create a local branch named "mywork" and make changes to it. | 
 | ``` | 
 |   cd src | 
 |   git new-branch mywork | 
 |   vi ... | 
 | ``` | 
 | Commit your change locally. (this doesn't commit your change to the SVN or Git | 
 | server) | 
 |  | 
 | ``` | 
 |   git commit -a | 
 | ``` | 
 |  | 
 | Fix your source code formatting. | 
 |  | 
 | ``` | 
 | $ git cl format | 
 | ``` | 
 |  | 
 | Upload your change for review. | 
 |  | 
 | ``` | 
 | $ git cl upload | 
 | ``` | 
 |  | 
 | Respond to review comments. | 
 |  | 
 | See [Contributing code](http://www.chromium.org/developers/contributing-code) | 
 | for more detailed git instructions, including how to update your CL when you get | 
 | review comments. There's a short tutorial that might be helpful to try before | 
 | making your first change: [C++ in Chromium | 
 | 101](http://dev.chromium.org/developers/cpp-in-chromium-101-codelab). | 
 |  | 
 | To land a change after receiving LGTM: | 
 | ``` | 
 | $ git cl land | 
 | ``` | 
 |  | 
 | Don't break the build! Waterfall is here: | 
 | http://build.chromium.org/p/client.mojo/waterfall |