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For Developers‎ > ‎How-Tos‎ > ‎

Get the Code

Contents

  1. 1 Bootstrap using the tarball
  2. 2 Check out directly from SVN
    1. 2.1 Windows
    2. 2.2 Mac OS X
    3. 2.3 Linux
  3. 3 Staying Green most of the time
    1. 3.1 Continuous build
      1. 3.1.1 LKGR
      2. 3.1.2 Setup
  4. 4 Reducing the size of your checkout
  5. 5 Update to the latest revision
The Chromium codebase consists of hundreds of thousands of files, which means that a checkout straight from the Subversion (SVN) repository can take a long time. To speed up the process, we have provided a tarball that you can use to bootstrap the download. Alternatively, you can skip the tarball and download straight from SVN (not recommended).

Note: There is no advantage to checking out straight from SVN. The tarball includes SVN directories so that after you unpack the tarball, you can get up to the latest revision by using gclient sync.

If you just want to just browse the code, you can do so online without checking it out.

If you only want to look at the source code on your own machine, you'll need at least 1.6 GB of hard drive space available. (Somewhat less for Linux, since it already has some of the dependencies installed.) If you want to build it, you will need just under 10 GB of space, including all the object files and executables.

Bootstrap using the tarball

  1. Make sure that you have a program that can untar .tgz (.tar.gz) files.
    • Mac OS X and Linux both have tar built in. (On a Mac, use a shell in the Terminal application.)
    • Examples for Windows include the open-source 7-Zip archiver, the free BsdTar utility (part of LibArchive), and WinZip.  Note: Cygwin's tar tool will not work; it will mess up the file permissions.
  2. Download the source tarball. Some download applications change the file suffix without extracting the file.  If yours did, rename it back to chromium.rXXXXX.tgz.
  3. Choose a directory to hold your source code.  Important: Make sure the directory path has no spaces.
    • Windows example: c:\chromiumtrunk
    • Mac OS X (Terminal) or Linux example: ~/chromium
  4. Untar the source tarball into the directory you've chosen. Examples: If you're using 7-Zip, extract the .tgz file, then extract the resulting .tar file. If you're using LibArchive, issue the following command:
    "C:\Program Files\GnuWin32\bin\bsdtar.exe" -xzf chromium.tgz
  5. Install the depot_tools.
  6. Updating your checkout once by running gclient sync --force in the source code directory (~/chromium/src).
    1. If you don't want to sync, you need to generate the project files with gclient runhooks --force. This will call GYP to generate your platform-specific files. You won't be able to build otherwise. If you don't sync, you'll miss some os-specific dependencies so you're better to sync anyway. :)
This should give you a complete source tree. But if you have any problems, first check that you've installed any prerequisites listed on the build instructions for your platform.

Check out directly from SVN

You'll use the gclient depot tool to download the Chromium code from its SVN repository. The first time you execute gclient, there will be a delay (a minute or so) while it updates the depot tools. Downloading the Chromium code takes about an hour.

The gclient config step only needs to be run once to set up your working directory.  It creates a .gclient file in your working directory that identifies the corresponding structure to pull from the repository.  The gclient sync step creates several subdirectories.  To update your tree in the future, you only need to run gclient sync from anywhere within your working directory.

NOTE: These instructions will pull a read-only tree.  If you are a committer, and plan to make changes to source code, use the instructions given to you when you received commit access.

Windows

Note: It's not necessary to have Subversion or Python installed already: the first run of gclient will install them for you. On the other hand, if you do already have Subversion installed through Cygwin, you'll need to set up your PATH to have the depot_tools svn ahead of the cygwin svn, and use only the depot_tools svn, not Cygwin's, to check out Chromium.
  1. Create a directory to hold your source code. This example assumes c:\chromiumtrunk, but other names are fine.
     Important: Make sure the full directory path has no spaces.
  2. In a shell window, execute the following commands:
    cd c:\chromiumtrunk
    gclient config http://src.chromium.org/svn/trunk/src
    To download the initial code, update your checkout as described below.

Mac OS X

  1. Create a directory to hold the code.  This example assumes the directory is ~/chromium, but other names are fine.
  2. From a shell in the Terminal, execute the following commands:
    $ cd ~/chromium
    $ gclient config http://src.chromium.org/svn/trunk/src
  3. To download the initial code, update your checkout as described below.

Linux

  1. Pick a directory for your build.  We will call this directory $CHROMIUM_ROOT below.
  2. Check out Chromium:
    $ cd $CHROMIUM_ROOT
    $ gclient config http://src.chromium.org/svn/trunk/src
  3. To download the initial code, update your checkout as described below.

Staying Green most of the time

When running gclient config, you can specify a second URL to be referenced when doing updates. Instead of pulling the most recent revision, the version number at this URL will be queried, allowing you to track the "most recent green" revision so you can spend less time debugging other people's issues or running builds only to find out that the waterfall was red. Chromium has two of these URLs:

Continuous build

  • http://build.chromium.org/buildbot/continuous/LATEST/REVISION
    This corresponds to the most recent revision that passed both unit tests and layout tests. Since layout tests can take a while to run, this revision may be an hour or more "stale".

LKGR

  • http://chromium-status.appspot.com/lkgr
    This URL holds the version of the latest revision to pass only unit tests (in debug mode). This can happen faster, so for most developers this is probably what you want since it will help you ensure that your changes work against a "fresher" version of Chromium.

Setup

To use one of these URLs, pass it when you run gclient config:
    $ cd ~/chromium
    $ gclient config http://src.chromium.org/svn/trunk/src http://chromium-status.appspot.com/lkgr

Now whenever you call gclient sync, it will only sync as far as the configured URL specifies. To over-ride this, pass the --head parameter to gclient, e.g.: gclient sync --head

You can also add this directly to your .gclient file if you already have one:

solutions = [
  { "name" : "src",
    "url"  : "http://src.chromium.org/svn/trunk/src",
    "safesync_url" : "http://chromium-status.appspot.com/lkgr"
  },
]

Reducing the size of your checkout

You can edit your .gclient file to avoid pulling down certain pieces of the checkout that you may not want. For example, inserting something like
    "custom_deps" : {
      "src/third_party/WebKit/LayoutTests": None,
    }
into one of the solutions (i.e. just underneath the "url": ... line) should save a lot of space. The list of repos that gclient pulls is stored in src/DEPS.

Update to the latest revision

Whether you started with a source tarball or an svn checkout, at some point you'll want to update your checkout to the latest revision.

The first time you execute gclient, there will be a delay (a minute or so) while it updates the depot tools. How long the Chromium code update takes depends on how much has changed since you last updated (or since the bootstrap tarball was created).
  1. Install the depot_tools, if you haven't already.
  2. Visit the Chromium Buildbot waterfall to see the state of the tree.  If the top of the waterfall says:
    OPEN - The tree is in a good state and you should be able to compile the code. Go to the next step.
    CLOSED     - There might be compile or test failures. You can download the code, but you'll get those same failures when you try to compile or run tests. Best to check back later.
  3. In a shell window, execute the following commands:
    cd [your Chromium source directory]
    gclient sync
To update to a specific revision, use
gclient sync --revision src@####

and the DEPS file will make sure you get the other directories in their matching forms.