README.md

   1 libgit2 - the Git linkable library
   2 ==================================
   3
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   7
   8 `libgit2` is a portable, pure C implementation of the Git core methods
   9 provided as a re-entrant linkable library with a solid API, allowing you to
  10 write native speed custom Git applications in any language with bindings.
  11
  12 `libgit2` is licensed under a **very permissive license** (GPLv2 with a special
  13 Linking Exception).  This basically means that you can link it (unmodified)
  14 with any kind of software without having to release its source code.
  15 Additionally, the example code has been released to the public domain (see the
  16 [separate license](examples/COPYING) for more information).
  17
  18 Getting Help
  19 ============
  20
  21 **Join us on Slack**
  22
  23 Visit [slack.libgit2.org](http://slack.libgit2.org/) to sign up, then join
  24 us in `#libgit2`.  If you prefer IRC, you can also point your client to our
  25 slack channel once you've registered.
  26
  27 **Getting Help**
  28
  29 If you have questions about the library, please be sure to check out the
  30 [API documentation](http://libgit2.github.com/libgit2/).  If you still have
  31 questions, reach out to us on Slack or post a question on
  32 [StackOverflow](http://stackoverflow.com/questions/tagged/libgit2) (with the `libgit2` tag).
  33
  34 **Reporting Bugs**
  35
  36 Please open a [GitHub Issue](https://github.com/libgit2/libgit2/issues) and
  37 include as much information as possible.  If possible, provide sample code
  38 that illustrates the problem you're seeing.  If you're seeing a bug only
  39 on a specific repository, please provide a link to it if possible.
  40
  41 We ask that you not open a GitHub Issue for help, only for bug reports.
  42
  43 What It Can Do
  44 ==============
  45
  46 The goal of this library is to allow its users the ability to handle Git data in
  47 their applications from their programming language of choice, as is used in
  48 production for many applications including the GitHub.com site, in Plastic SCM
  49 and also powering Microsoft's Visual Studio tools for Git.
  50
  51 It does not aim to replace the git tool or its user-facing commands. Some APIs
  52 resemble the plumbing commands as those align closely with the concepts of the
  53 Git system, but most commands a user would type are out of scope for this
  54 library to implement directly.
  55
  56 The library provides:
  57
  58 * SHA conversions, formatting and shortening
  59 * abstracted ODB backend system
  60 * commit, tag, tree and blob parsing, editing, and write-back
  61 * tree traversal
  62 * revision walking
  63 * index file (staging area) manipulation
  64 * reference management (including packed references)
  65 * config file management
  66 * high level repository management
  67 * thread safety and reentrancy
  68 * descriptive and detailed error messages
  69 * ...and more (over 175 different API calls)
  70
  71 As libgit2 is purely a consumer of the Git system, we have to
  72 adjust to changes made upstream. This has two major consequences:
  73
  74 * Some changes may require us to change provided interfaces. While we try to
  75   implement functions in a generic way so that no future changes are required,
  76   we cannot promise a completely stable API.
  77 * As we have to keep up with changes in behavior made upstream, we may lag
  78   behind in some areas. We usually to document these incompatibilities in our
  79   issue tracker with the label "git change".
  80
  81 Optional dependencies
  82 =====================
  83
  84 While the library provides git functionality without the need for
  85 dependencies, it can make use of a few libraries to add to it:
  86
  87 - pthreads (non-Windows) to enable threadsafe access as well as multi-threaded pack generation
  88 - OpenSSL (non-Windows) to talk over HTTPS and provide the SHA-1 functions
  89 - LibSSH2 to enable the SSH transport
  90 - iconv (OSX) to handle the HFS+ path encoding peculiarities
  91
  92 Initialization
  93 ===============
  94
  95 The library needs to keep track of some global state. Call
  96
  97     git_libgit2_init();
  98
  99 before calling any other libgit2 functions. You can call this function many times. A matching number of calls to
 100
 101     git_libgit2_shutdown();
 102
 103 will free the resources.  Note that if you have worker threads, you should
 104 call `git_libgit2_shutdown` *after* those threads have exited.  If you
 105 require assistance coordinating this, simply have the worker threads call
 106 `git_libgit2_init` at startup and `git_libgit2_shutdown` at shutdown.
 107
 108 Threading
 109 =========
 110
 111 See [THREADING](THREADING.md) for information
 112
 113 Conventions
 114 ===========
 115
 116 See [CONVENTIONS](CONVENTIONS.md) for an overview of the external
 117 and internal API/coding conventions we use.
 118
 119 Building libgit2 - Using CMake
 120 ==============================
 121
 122 `libgit2` builds cleanly on most platforms without any external dependencies.
 123 Under Unix-like systems, like Linux, \*BSD and Mac OS X, libgit2 expects `pthreads` to be available;
 124 they should be installed by default on all systems. Under Windows, libgit2 uses the native Windows API
 125 for threading.
 126
 127 The `libgit2` library is built using [CMake](<https://cmake.org/>) (version 2.8 or newer) on all platforms.
 128
 129 On most systems you can build the library using the following commands
 130
 131         $ mkdir build && cd build
 132         $ cmake ..
 133         $ cmake --build .
 134
 135 Alternatively you can point the CMake GUI tool to the CMakeLists.txt file and generate platform specific build project or IDE workspace.
 136
 137 Once built, you can run the tests from the `build` directory with the command
 138
 139         $ make test
 140
 141 Alternatively you can run the test suite directly using,
 142
 143         $ ./libgit2_clar
 144
 145 To install the library you can specify the install prefix by setting:
 146
 147         $ cmake .. -DCMAKE_INSTALL_PREFIX=/install/prefix
 148         $ cmake --build . --target install
 149
 150 For more advanced use or questions about CMake please read <https://cmake.org/Wiki/CMake_FAQ>.
 151
 152 The following CMake variables are declared:
 153
 154 - `BIN_INSTALL_DIR`: Where to install binaries to.
 155 - `LIB_INSTALL_DIR`: Where to install libraries to.
 156 - `INCLUDE_INSTALL_DIR`: Where to install headers to.
 157 - `BUILD_SHARED_LIBS`: Build libgit2 as a Shared Library (defaults to ON)
 158 - `BUILD_CLAR`: Build [Clar](https://github.com/vmg/clar)-based test suite (defaults to ON)
 159 - `THREADSAFE`: Build libgit2 with threading support (defaults to ON)
 160 - `STDCALL`: Build libgit2 as `stdcall`. Turn off for `cdecl` (Windows; defaults to ON)
 161
 162 Compiler and linker options
 163 ---------------------------
 164
 165 CMake lets you specify a few variables to control the behavior of the
 166 compiler and linker. These flags are rarely used but can be useful for
 167 64-bit to 32-bit cross-compilation.
 168
 169 - `CMAKE_C_FLAGS`: Set your own compiler flags
 170 - `CMAKE_FIND_ROOT_PATH`: Override the search path for libraries
 171 - `ZLIB_LIBRARY`, `OPENSSL_SSL_LIBRARY` AND `OPENSSL_CRYPTO_LIBRARY`:
 172 Tell CMake where to find those specific libraries
 173
 174 MacOS X
 175 -------
 176
 177 If you want to build a universal binary for Mac OS X, CMake sets it
 178 all up for you if you use `-DCMAKE_OSX_ARCHITECTURES="i386;x86_64"`
 179 when configuring.
 180
 181 Windows
 182 -------
 183
 184 You need to run the CMake commands from the Visual Studio command
 185 prompt, not the regular or Windows SDK one. Select the right generator
 186 for your version with the `-G "Visual Studio X" option.
 187
 188 See [the website](http://libgit2.github.com/docs/guides/build-and-link/)
 189 for more detailed instructions.
 190
 191 Android
 192 -------
 193
 194 Extract toolchain from NDK using, `make-standalone-toolchain.sh` script.
 195 Optionally, crosscompile and install OpenSSL inside of it. Then create CMake
 196 toolchain file that configures paths to your crosscompiler (substitute `{PATH}`
 197 with full path to the toolchain):
 198
 199         SET(CMAKE_SYSTEM_NAME Linux)
 200         SET(CMAKE_SYSTEM_VERSION Android)
 201
 202         SET(CMAKE_C_COMPILER   {PATH}/bin/arm-linux-androideabi-gcc)
 203         SET(CMAKE_CXX_COMPILER {PATH}/bin/arm-linux-androideabi-g++)
 204         SET(CMAKE_FIND_ROOT_PATH {PATH}/sysroot/)
 205
 206         SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 207         SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 208         SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 209
 210 Add `-DCMAKE_TOOLCHAIN_FILE={pathToToolchainFile}` to cmake command
 211 when configuring.
 212
 213 Language Bindings
 214 ==================================
 215
 216 Here are the bindings to libgit2 that are currently available:
 217
 218 * C++
 219     * libqgit2, Qt bindings <https://projects.kde.org/projects/playground/libs/libqgit2/repository/>
 220 * Chicken Scheme
 221     * chicken-git <https://wiki.call-cc.org/egg/git>
 222 * D
 223     * dlibgit <https://github.com/s-ludwig/dlibgit>
 224 * Delphi
 225     * GitForDelphi <https://github.com/libgit2/GitForDelphi>
 226 * Erlang
 227     * Geef <https://github.com/carlosmn/geef>
 228 * Go
 229     * git2go <https://github.com/libgit2/git2go>
 230 * GObject
 231     * libgit2-glib <https://wiki.gnome.org/Projects/Libgit2-glib>
 232 * Haskell
 233     * hgit2 <https://github.com/jwiegley/gitlib>
 234 * Java
 235     * Jagged <https://github.com/ethomson/jagged>
 236 * Julia
 237     * LibGit2.jl <https://github.com/jakebolewski/LibGit2.jl>
 238 * Lua
 239     * luagit2 <https://github.com/libgit2/luagit2>
 240 * .NET
 241     * libgit2sharp <https://github.com/libgit2/libgit2sharp>
 242 * Node.js
 243     * nodegit <https://github.com/nodegit/nodegit>
 244 * Objective-C
 245     * objective-git <https://github.com/libgit2/objective-git>
 246 * OCaml
 247     * ocaml-libgit2 <https://github.com/fxfactorial/ocaml-libgit2>
 248 * Parrot Virtual Machine
 249     * parrot-libgit2 <https://github.com/letolabs/parrot-libgit2>
 250 * Perl
 251     * Git-Raw <https://github.com/jacquesg/p5-Git-Raw>
 252 * PHP
 253     * php-git <https://github.com/libgit2/php-git>
 254 * PowerShell
 255     * PSGit <https://github.com/PoshCode/PSGit>
 256 * Python
 257     * pygit2 <https://github.com/libgit2/pygit2>
 258 * R
 259     * git2r <https://github.com/ropensci/git2r>
 260 * Ruby
 261     * Rugged <https://github.com/libgit2/rugged>
 262 * Rust
 263     * git2-rs <https://github.com/alexcrichton/git2-rs>
 264 * Swift
 265     * SwiftGit2 <https://github.com/SwiftGit2/SwiftGit2>
 266 * Vala
 267     * libgit2.vapi <https://github.com/apmasell/vapis/blob/master/libgit2.vapi>
 268
 269 If you start another language binding to libgit2, please let us know so
 270 we can add it to the list.
 271
 272 How Can I Contribute?
 273 ==================================
 274
 275 We welcome new contributors!  We have a number of issues marked as
 276 ["up for grabs"](https://github.com/libgit2/libgit2/issues?q=is%3Aissue+is%3Aopen+label%3A%22up+for+grabs%22)
 277 and
 278 ["easy fix"](https://github.com/libgit2/libgit2/issues?utf8=✓&q=is%3Aissue+is%3Aopen+label%3A%22easy+fix%22)
 279 that are good places to jump in and get started.  There's much more detailed
 280 information in our list of [outstanding projects](PROJECTS.md).
 281
 282 Please be sure to check the [contribution guidelines](CONTRIBUTING.md) to
 283 understand our workflow, and the libgit2 [coding conventions](CONVENTIONS.md).
 284
 285 License
 286 ==================================
 287
 288 `libgit2` is under GPL2 **with linking exception**. This means you can link to
 289 and use the library from any program, proprietary or open source; paid or
 290 gratis.  However, if you modify libgit2 itself, you must distribute the
 291 source to your modified version of libgit2.
 292
 293 See the [COPYING file](COPYING) for the full license text.