_ _ ____ _ ___| | | | _ \| | / __| | | | |_) | | | (__| |_| | _ <| |___ \___|\___/|_| \_\_____| When Contributing Source Code This document is intended to offer guidelines that can be useful to keep in mind when you decide to contribute to the project. This concerns new features as well as corrections to existing flaws or bugs. 1. Learning cURL 1.1 Join the Community 1.2 License 1.3 What To Read 2. cURL Coding Standards 2.1 Naming 2.2 Indenting 2.3 Commenting 2.4 Line Lengths 2.5 General Style 2.6 Non-clobbering All Over 2.7 Platform Dependent Code 2.8 Write Separate Patches 2.9 Patch Against Recent Sources 2.10 Document 2.11 Test Cases 3. Pushing Out Your Changes 3.1 Write Access to git Repository 3.2 How To Make a Patch with git 3.3 How To Make a Patch without git 3.4 How to get your changes into the main sources 3.5 Write good commit messages ============================================================================== 1. Learning cURL 1.1 Join the Community Skip over to http://curl.haxx.se/mail/ and join the appropriate mailing list(s). Read up on details before you post questions. Read this file before you start sending patches! We prefer patches and discussions being held on the mailing list(s), not sent to individuals. Before posting to one of the curl mailing lists, please read up on the mailing list etiquette: http://curl.haxx.se/mail/etiquette.html We also hang out on IRC in #curl on irc.freenode.net 1.2. License When contributing with code, you agree to put your changes and new code under the same license curl and libcurl is already using unless stated and agreed otherwise. If you add a larger piece of code, you can opt to make that file or set of files to use a different license as long as they don't enforce any changes to the rest of the package and they make sense. Such "separate parts" can not be GPL licensed (as we don't want copyleft to affect users of libcurl) but they must use "GPL compatible" licenses (as we want to allow users to use libcurl properly in GPL licensed environments). When changing existing source code, you do not alter the copyright of the original file(s). The copyright will still be owned by the original creator(s) or those who have been assigned copyright by the original author(s). By submitting a patch to the curl project, you are assumed to have the right to the code and to be allowed by your employer or whatever to hand over that patch/code to us. We will credit you for your changes as far as possible, to give credit but also to keep a trace back to who made what changes. Please always provide us with your full real name when contributing! 1.3 What To Read Source code, the man pages, the INTERNALS document, TODO, KNOWN_BUGS, the most recent CHANGES. Just lurking on the libcurl mailing list is gonna give you a lot of insights on what's going on right now. Asking there is a good idea too. 2. cURL Coding Standards 2.1 Naming Try using a non-confusing naming scheme for your new functions and variable names. It doesn't necessarily have to mean that you should use the same as in other places of the code, just that the names should be logical, understandable and be named according to what they're used for. File-local functions should be made static. We like lower case names. See the INTERNALS document on how we name non-exported library-global symbols. 2.2 Indenting Please try using the same indenting levels and bracing method as all the other code already does. It makes the source code a lot easier to follow if all of it is written using the same style. We don't ask you to like it, we just ask you to follow the tradition! ;-) This mainly means: 2-level indents, using spaces only (no tabs) and having the opening brace ({) on the same line as the if() or while(). Also note that we use if() and while() with no space before the parenthesis. 2.3 Commenting Comment your source code extensively using C comments (/* comment */), DO NOT use C++ comments (// this style). Commented code is quality code and enables future modifications much more. Uncommented code risk having to be completely replaced when someone wants to extend things, since other persons' source code can get quite hard to read. 2.4 Line Lengths We write source lines shorter than 80 columns. 2.5 General Style Keep your functions small. If they're small you avoid a lot of mistakes and you don't accidentally mix up variables etc. 2.6 Non-clobbering All Over When you write new functionality or fix bugs, it is important that you don't fiddle all over the source files and functions. Remember that it is likely that other people have done changes in the same source files as you have and possibly even in the same functions. If you bring completely new functionality, try writing it in a new source file. If you fix bugs, try to fix one bug at a time and send them as separate patches. 2.7 Platform Dependent Code Use #ifdef HAVE_FEATURE to do conditional code. We avoid checking for particular operating systems or hardware in the #ifdef lines. The HAVE_FEATURE shall be generated by the configure script for unix-like systems and they are hard-coded in the config-[system].h files for the others. 2.8 Write Separate Patches It is annoying when you get a huge patch from someone that is said to fix 511 odd problems, but discussions and opinions don't agree with 510 of them - or 509 of them were already fixed in a different way. Then the patcher needs to extract the single interesting patch from somewhere within the huge pile of source, and that gives a lot of extra work. Preferably, all fixes that correct different problems should be in their own patch with an attached description exactly what they correct so that all patches can be selectively applied by the maintainer or other interested parties. 2.9 Patch Against Recent Sources Please try to get the latest available sources to make your patches against. It makes the life of the developers so much easier. The very best is if you get the most up-to-date sources from the git repository, but the latest release archive is quite OK as well! 2.10 Document Writing docs is dead boring and one of the big problems with many open source projects. Someone's gotta do it. It makes it a lot easier if you submit a small description of your fix or your new features with every contribution so that it can be swiftly added to the package documentation. The documentation is always made in man pages (nroff formatted) or plain ASCII files. All HTML files on the web site and in the release archives are generated from the nroff/ASCII versions. 2.11 Test Cases Since the introduction of the test suite, we can quickly verify that the main features are working as they're supposed to. To maintain this situation and improve it, all new features and functions that are added need to be tested in the test suite. Every feature that is added should get at least one valid test case that verifies that it works as documented. If every submitter also posts a few test cases, it won't end up as a heavy burden on a single person! 3. Pushing Out Your Changes 3.1 Write Access to git Repository If you are a frequent contributor, or have another good reason, you can of course get write access to the git repository and then you'll be able to push your changes straight into the git repo instead of sending changes by mail as patches. Just ask if this is what you'd want. You will be required to have posted a few quality patches first, before you can be granted push access. 3.2 How To Make a Patch with git You need to first checkout the repository: git clone git://github.com/bagder/curl.git You then proceed and edit all the files you like and you commit them to your local repository: git commit [file] As usual, group your commits so that you commit all changes that at once that constitutes a logical change. See also section "3.5 Write good commit messages". Once you have done all your commits and you're happy with what you see, you can make patches out of your changes that are suitable for mailing: git format-patch remotes/origin/master This creates files in your local directory named NNNN-[name].patch for each commit. Now send those patches off to the curl-library list. You can of course opt to do that with the 'get send-email' command. 3.3 How To Make a Patch without git Keep a copy of the unmodified curl sources. Make your changes in a separate source tree. When you think you have something that you want to offer the curl community, use GNU diff to generate patches. If you have modified a single file, try something like: diff -u unmodified-file.c my-changed-one.c > my-fixes.diff If you have modified several files, possibly in different directories, you can use diff recursively: diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff The GNU diff and GNU patch tools exist for virtually all platforms, including all kinds of Unixes and Windows: For unix-like operating systems: http://www.gnu.org/software/patch/patch.html http://www.gnu.org/directory/diffutils.html For Windows: http://gnuwin32.sourceforge.net/packages/patch.htm http://gnuwin32.sourceforge.net/packages/diffutils.htm 3.4 How to get your changes into the main sources Submit your patch to the curl-library mailing list. Make the patch against as recent sources as possible. Make sure your patch adheres to the source indent and coding style of already existing source code. Failing to do so just adds more work for me. Respond to replies on the list about the patch and answer questions and/or fix nits/flaws. This is very important. I will take lack of replies as a sign that you're not very anxious to get your patch accepted and I tend to simply drop such patches from my TODO list. If you've followed the above paragraphs and your patch still hasn't been incorporated after some weeks, consider resubmitting it to the list. 3.5 Write good commit messages A short guide to how to do fine commit messages in the curl project. ---- start ---- [area]: [short line describing the main effect] [separate the above single line from the rest with an empty line] [full description, no wider than 72 columns that describe as much as possible as to why this change is made, and possibly what things it fixes and everything else that is related] ---- stop ---- Don't forget to use commit --author="" if you commit someone else's work, and make sure that you have your own user and email setup correctly in git before you commit