1 _ _ ____ _ 2 ___| | | | _ \| | 3 / __| | | | |_) | | 4 | (__| |_| | _ <| |___ 5 \___|\___/|_| \_\_____| 6 7 When Contributing Source Code 8 9 This document is intended to offer guidelines that can be useful to keep in 10 mind when you decide to contribute to the project. This concerns new features 11 as well as corrections to existing flaws or bugs. 12 13 1. Learning cURL 14 1.1 Join the Community 15 1.2 License 16 1.3 What To Read 17 18 2. cURL Coding Standards 19 2.1 Naming 20 2.2 Indenting 21 2.3 Commenting 22 2.4 Line Lengths 23 2.5 General Style 24 2.6 Non-clobbering All Over 25 2.7 Platform Dependent Code 26 2.8 Write Separate Patches 27 2.9 Patch Against Recent Sources 28 2.10 Document 29 2.11 Test Cases 30 31 3. Pushing Out Your Changes 32 3.1 Write Access to git Repository 33 3.2 How To Make a Patch with git 34 3.3 How To Make a Patch without git 35 3.4 How to get your changes into the main sources 36 3.5 Write good commit messages 37 38============================================================================== 39 401. Learning cURL 41 421.1 Join the Community 43 44 Skip over to http://curl.haxx.se/mail/ and join the appropriate mailing 45 list(s). Read up on details before you post questions. Read this file before 46 you start sending patches! We prefer patches and discussions being held on 47 the mailing list(s), not sent to individuals. 48 49 Before posting to one of the curl mailing lists, please read up on the mailing 50 list etiquette: http://curl.haxx.se/mail/etiquette.html 51 52 We also hang out on IRC in #curl on irc.freenode.net 53 541.2. License 55 56 When contributing with code, you agree to put your changes and new code under 57 the same license curl and libcurl is already using unless stated and agreed 58 otherwise. 59 60 If you add a larger piece of code, you can opt to make that file or set of 61 files to use a different license as long as they don't enforce any changes to 62 the rest of the package and they make sense. Such "separate parts" can not be 63 GPL licensed (as we don't want copyleft to affect users of libcurl) but they 64 must use "GPL compatible" licenses (as we want to allow users to use libcurl 65 properly in GPL licensed environments). 66 67 When changing existing source code, you do not alter the copyright of the 68 original file(s). The copyright will still be owned by the original 69 creator(s) or those who have been assigned copyright by the original 70 author(s). 71 72 By submitting a patch to the curl project, you are assumed to have the right 73 to the code and to be allowed by your employer or whatever to hand over that 74 patch/code to us. We will credit you for your changes as far as possible, to 75 give credit but also to keep a trace back to who made what changes. Please 76 always provide us with your full real name when contributing! 77 781.3 What To Read 79 80 Source code, the man pages, the INTERNALS document, TODO, KNOWN_BUGS, the 81 most recent CHANGES. Just lurking on the libcurl mailing list is gonna give 82 you a lot of insights on what's going on right now. Asking there is a good 83 idea too. 84 852. cURL Coding Standards 86 872.1 Naming 88 89 Try using a non-confusing naming scheme for your new functions and variable 90 names. It doesn't necessarily have to mean that you should use the same as in 91 other places of the code, just that the names should be logical, 92 understandable and be named according to what they're used for. File-local 93 functions should be made static. We like lower case names. 94 95 See the INTERNALS document on how we name non-exported library-global 96 symbols. 97 982.2 Indenting 99 100 Please try using the same indenting levels and bracing method as all the 101 other code already does. It makes the source code a lot easier to follow if 102 all of it is written using the same style. We don't ask you to like it, we 103 just ask you to follow the tradition! ;-) This mainly means: 2-level indents, 104 using spaces only (no tabs) and having the opening brace ({) on the same line 105 as the if() or while(). 106 107 Also note that we use if() and while() with no space before the parenthesis. 108 1092.3 Commenting 110 111 Comment your source code extensively using C comments (/* comment */), DO NOT 112 use C++ comments (// this style). Commented code is quality code and enables 113 future modifications much more. Uncommented code risk having to be completely 114 replaced when someone wants to extend things, since other persons' source 115 code can get quite hard to read. 116 1172.4 Line Lengths 118 119 We write source lines shorter than 80 columns. 120 1212.5 General Style 122 123 Keep your functions small. If they're small you avoid a lot of mistakes and 124 you don't accidentally mix up variables etc. 125 1262.6 Non-clobbering All Over 127 128 When you write new functionality or fix bugs, it is important that you don't 129 fiddle all over the source files and functions. Remember that it is likely 130 that other people have done changes in the same source files as you have and 131 possibly even in the same functions. If you bring completely new 132 functionality, try writing it in a new source file. If you fix bugs, try to 133 fix one bug at a time and send them as separate patches. 134 1352.7 Platform Dependent Code 136 137 Use #ifdef HAVE_FEATURE to do conditional code. We avoid checking for 138 particular operating systems or hardware in the #ifdef lines. The 139 HAVE_FEATURE shall be generated by the configure script for unix-like systems 140 and they are hard-coded in the config-[system].h files for the others. 141 1422.8 Write Separate Patches 143 144 It is annoying when you get a huge patch from someone that is said to fix 511 145 odd problems, but discussions and opinions don't agree with 510 of them - or 146 509 of them were already fixed in a different way. Then the patcher needs to 147 extract the single interesting patch from somewhere within the huge pile of 148 source, and that gives a lot of extra work. Preferably, all fixes that 149 correct different problems should be in their own patch with an attached 150 description exactly what they correct so that all patches can be selectively 151 applied by the maintainer or other interested parties. 152 1532.9 Patch Against Recent Sources 154 155 Please try to get the latest available sources to make your patches 156 against. It makes the life of the developers so much easier. The very best is 157 if you get the most up-to-date sources from the git repository, but the 158 latest release archive is quite OK as well! 159 1602.10 Document 161 162 Writing docs is dead boring and one of the big problems with many open source 163 projects. Someone's gotta do it. It makes it a lot easier if you submit a 164 small description of your fix or your new features with every contribution so 165 that it can be swiftly added to the package documentation. 166 167 The documentation is always made in man pages (nroff formatted) or plain 168 ASCII files. All HTML files on the web site and in the release archives are 169 generated from the nroff/ASCII versions. 170 1712.11 Test Cases 172 173 Since the introduction of the test suite, we can quickly verify that the main 174 features are working as they're supposed to. To maintain this situation and 175 improve it, all new features and functions that are added need to be tested 176 in the test suite. Every feature that is added should get at least one valid 177 test case that verifies that it works as documented. If every submitter also 178 posts a few test cases, it won't end up as a heavy burden on a single person! 179 1803. Pushing Out Your Changes 181 1823.1 Write Access to git Repository 183 184 If you are a frequent contributor, or have another good reason, you can of 185 course get write access to the git repository and then you'll be able to push 186 your changes straight into the git repo instead of sending changes by mail as 187 patches. Just ask if this is what you'd want. You will be required to have 188 posted a few quality patches first, before you can be granted push access. 189 1903.2 How To Make a Patch with git 191 192 You need to first checkout the repository: 193 194 git clone git://github.com/bagder/curl.git 195 196 You then proceed and edit all the files you like and you commit them to your 197 local repository: 198 199 git commit [file] 200 201 As usual, group your commits so that you commit all changes that at once that 202 constitutes a logical change. See also section "3.5 Write good commit 203 messages". 204 205 Once you have done all your commits and you're happy with what you see, you 206 can make patches out of your changes that are suitable for mailing: 207 208 git format-patch remotes/origin/master 209 210 This creates files in your local directory named NNNN-[name].patch for each 211 commit. 212 213 Now send those patches off to the curl-library list. You can of course opt to 214 do that with the 'get send-email' command. 215 2163.3 How To Make a Patch without git 217 218 Keep a copy of the unmodified curl sources. Make your changes in a separate 219 source tree. When you think you have something that you want to offer the 220 curl community, use GNU diff to generate patches. 221 222 If you have modified a single file, try something like: 223 224 diff -u unmodified-file.c my-changed-one.c > my-fixes.diff 225 226 If you have modified several files, possibly in different directories, you 227 can use diff recursively: 228 229 diff -ur curl-original-dir curl-modified-sources-dir > my-fixes.diff 230 231 The GNU diff and GNU patch tools exist for virtually all platforms, including 232 all kinds of Unixes and Windows: 233 234 For unix-like operating systems: 235 236 http://www.gnu.org/software/patch/patch.html 237 http://www.gnu.org/directory/diffutils.html 238 239 For Windows: 240 241 http://gnuwin32.sourceforge.net/packages/patch.htm 242 http://gnuwin32.sourceforge.net/packages/diffutils.htm 243 2443.4 How to get your changes into the main sources 245 246 Submit your patch to the curl-library mailing list. 247 248 Make the patch against as recent sources as possible. 249 250 Make sure your patch adheres to the source indent and coding style of already 251 existing source code. Failing to do so just adds more work for me. 252 253 Respond to replies on the list about the patch and answer questions and/or 254 fix nits/flaws. This is very important. I will take lack of replies as a sign 255 that you're not very anxious to get your patch accepted and I tend to simply 256 drop such patches from my TODO list. 257 258 If you've followed the above paragraphs and your patch still hasn't been 259 incorporated after some weeks, consider resubmitting it to the list. 260 2613.5 Write good commit messages 262 263 A short guide to how to do fine commit messages in the curl project. 264 265 ---- start ---- 266 [area]: [short line describing the main effect] 267 268 [separate the above single line from the rest with an empty line] 269 270 [full description, no wider than 72 columns that describe as much as 271 possible as to why this change is made, and possibly what things 272 it fixes and everything else that is related] 273 ---- stop ---- 274 275 Don't forget to use commit --author="" if you commit someone else's work, 276 and make sure that you have your own user and email setup correctly in git 277 before you commit 278 279