## Basic overview `./configure.py` generates the `build.ninja` files used to build ninja. It accepts various flags to adjust build parameters. The primary build target of interest is `ninja`, but when hacking on Ninja your changes should be testable so it's more useful to build and run `ninja_test` when developing. (`./bootstrap.py` creates a bootstrap `ninja` and runs the above process; it's only necessary to run if you don't have a copy of `ninja` to build with.) ### Adjusting build flags Build in "debug" mode while developing (disables optimizations and builds way faster on Windows): ./configure.py --debug To use clang, set `CXX`: CXX=clang++ ./configure.py ## How to successfully make changes to Ninja Github pull requests are convenient for me to merge (I can just click a button and it's all handled server-side), but I'm also comfortable accepting pre-github git patches (via `send-email` etc.). Good pull requests have all of these attributes: * Are scoped to one specific issue * Include a test to demonstrate their correctness * Update the docs where relevant * Match the Ninja coding style (see below) * Don't include a mess of "oops, fix typo" commits These are typically merged without hesitation. If a change is lacking any of the above I usually will ask you to fix it, though there are obvious exceptions (fixing typos in comments don't need tests). I am very wary of changes that increase the complexity of Ninja (in particular, new build file syntax or command-line flags) or increase the maintenance burden of Ninja. Ninja is already successfully in use by hundreds of developers for large projects and it already achieves (most of) the goals I set out for it to do. It's probably best to discuss new feature ideas on the mailing list before I shoot down your patch. ## Testing ### Installing gtest The `ninja_test` binary, containing all the tests, depends on the googletest (gtest) library. * On older Ubuntus it'll install as libraries into `/usr/lib`: apt-get install libgtest * On newer Ubuntus it's only distributed as source apt-get install libgtest-dev ./configure.py --with-gtest=/usr/src/gtest * Otherwise you need to download it, unpack it, and pass `--with-gtest` to `configure.py`. Get it from [its downloads page](http://code.google.com/p/googletest/downloads/list); [this direct download link might work too](http://googletest.googlecode.com/files/gtest-1.6.0.zip). ### Test-driven development Set your build command to ./ninja ninja_test && ./ninja_test --gtest_filter=MyTest.Name now you can repeatedly run that while developing until the tests pass (I frequently set it as my compilation command in Emacs). Remember to build "all" before committing to verify the other source still works! ## Testing performance impact of changes If you have a Chrome build handy, it's a good test case. Otherwise, [the github downoads page](https://github.com/martine/ninja/downloads) has a copy of the Chrome build files (and depfiles). You can untar that, then run path/to/my/ninja chrome and compare that against a baseline Ninja. There's a script at `misc/measure.py` that repeatedly runs a command like the above (to address variance) and summarizes its runtime. E.g. path/to/misc/measure.py path/to/my/ninja chrome For changing the depfile parser, you can also build `parser_perftest` and run that directly on some representative input files. ## Coding guidelines Generally it's the [Google C++ coding style][], but in brief: * Function name are camelcase. * Member methods are camelcase, expect for trivial getters which are underscore separated. * Local variables are underscore separated. * Member variables are underscore separated and suffixed by an extra underscore. * Two spaces indentation. * Opening braces is at the end of line. * Lines are 80 columns maximum. * All source files should have the Google Inc. license header. [Google C++ coding style]: http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml ## Documentation ### Style guidelines * Use `///` for doxygen. * Use `\a` to refer to arguments. * It's not necessary to document each argument, especially when they're relatively self-evident (e.g. in `CanonicalizePath(string* path, string* err)`, the arguments are hopefully obvious) ### Building the manual sudo apt-get install asciidoc --no-install-recommends ./ninja manual ### Building the code documentation sudo apt-get install doxygen ./ninja doxygen ## Building for Windows While developing, it's helpful to copy `ninja.exe` to another name like `n.exe`; otherwise, rebuilds will be unable to write `ninja.exe` because it's locked while in use. ### Via Visual Studio * Install Visual Studio (Express is fine), [Python for Windows][], and (if making changes) googletest (see above instructions) * In a Visual Studio command prompt: `python bootstrap.py` [Python for Windows]: http://www.python.org/getit/windows/ ### Via mingw on Windows (not well supported) * Install mingw, msys, and python * In the mingw shell, put Python in your path, and `python bootstrap.py` * To reconfigure, run `python configure.py` * Remember to strip the resulting executable if size matters to you ### Via mingw on Linux (not well supported) Setup on Ubuntu Lucid: * `sudo apt-get install gcc-mingw32 wine` * `export CC=i586-mingw32msvc-cc CXX=i586-mingw32msvc-c++ AR=i586-mingw32msvc-ar` Setup on Ubuntu Precise: * `sudo apt-get install gcc-mingw-w64-i686 g++-mingw-w64-i686 wine` * `export CC=i686-w64-mingw32-gcc CXX=i686-w64-mingw32-g++ AR=i686-w64-mingw32-ar` Then run: * `./configure.py --platform=mingw --host=linux` * Build `ninja.exe` using a Linux ninja binary: `/path/to/linux/ninja` * Run: `./ninja.exe` (implicitly runs through wine(!)) ### Using Microsoft compilers on Linux (extremely flaky) The trick is to install just the compilers, and not all of Visual Studio, by following [these instructions][win7sdk]. [win7sdk]: http://www.kegel.com/wine/cl-howto-win7sdk.html