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 Optional dependencies
  72 =====================
  73
  74 While the library provides git functionality without the need for
  75 dependencies, it can make use of a few libraries to add to it:
  76
  77 - pthreads (non-Windows) to enable threadsafe access as well as multi-threaded pack generation
  78 - OpenSSL (non-Windows) to talk over HTTPS and provide the SHA-1 functions
  79 - LibSSH2 to enable the SSH transport
  80 - iconv (OSX) to handle the HFS+ path encoding peculiarities
  81
  82 Initialization
  83 ===============
  84
  85 The library needs to keep track of some global state. Call
  86
  87     git_libgit2_init();
  88
  89 before calling any other libgit2 functions. You can call this function many times. A matching number of calls to
  90
  91     git_libgit2_shutdown();
  92
  93 will free the resources.  Note that if you have worker threads, you should
  94 call `git_libgit2_shutdown` *after* those threads have exited.  If you
  95 require assistance coordinating this, simply have the worker threads call
  96 `git_libgit2_init` at startup and `git_libgit2_shutdown` at shutdown.
  97
  98 Threading
  99 =========
 100
 101 See [THREADING](THREADING.md) for information
 102
 103 Conventions
 104 ===========
 105
 106 See [CONVENTIONS](CONVENTIONS.md) for an overview of the external
 107 and internal API/coding conventions we use.
 108
 109 Building libgit2 - Using CMake
 110 ==============================
 111
 112 `libgit2` builds cleanly on most platforms without any external dependencies.
 113 Under Unix-like systems, like Linux, \*BSD and Mac OS X, libgit2 expects `pthreads` to be available;
 114 they should be installed by default on all systems. Under Windows, libgit2 uses the native Windows API
 115 for threading.
 116
 117 The `libgit2` library is built using [CMake](<https://cmake.org/>) (version 2.8 or newer) on all platforms.
 118
 119 On most systems you can build the library using the following commands
 120
 121         $ mkdir build && cd build
 122         $ cmake ..
 123         $ cmake --build .
 124
 125 Alternatively you can point the CMake GUI tool to the CMakeLists.txt file and generate platform specific build project or IDE workspace.
 126
 127 To install the library you can specify the install prefix by setting:
 128
 129         $ cmake .. -DCMAKE_INSTALL_PREFIX=/install/prefix
 130         $ cmake --build . --target install
 131
 132 For more advanced use or questions about CMake please read <https://cmake.org/Wiki/CMake_FAQ>.
 133
 134 The following CMake variables are declared:
 135
 136 - `BIN_INSTALL_DIR`: Where to install binaries to.
 137 - `LIB_INSTALL_DIR`: Where to install libraries to.
 138 - `INCLUDE_INSTALL_DIR`: Where to install headers to.
 139 - `BUILD_SHARED_LIBS`: Build libgit2 as a Shared Library (defaults to ON)
 140 - `BUILD_CLAR`: Build [Clar](https://github.com/vmg/clar)-based test suite (defaults to ON)
 141 - `THREADSAFE`: Build libgit2 with threading support (defaults to ON)
 142 - `STDCALL`: Build libgit2 as `stdcall`. Turn off for `cdecl` (Windows; defaults to ON)
 143
 144 Compiler and linker options
 145 ---------------------------
 146
 147 CMake lets you specify a few variables to control the behavior of the
 148 compiler and linker. These flags are rarely used but can be useful for
 149 64-bit to 32-bit cross-compilation.
 150
 151 - `CMAKE_C_FLAGS`: Set your own compiler flags
 152 - `CMAKE_FIND_ROOT_PATH`: Override the search path for libraries
 153 - `ZLIB_LIBRARY`, `OPENSSL_SSL_LIBRARY` AND `OPENSSL_CRYPTO_LIBRARY`:
 154 Tell CMake where to find those specific libraries
 155
 156 MacOS X
 157 -------
 158
 159 If you want to build a universal binary for Mac OS X, CMake sets it
 160 all up for you if you use `-DCMAKE_OSX_ARCHITECTURES="i386;x86_64"`
 161 when configuring.
 162
 163 Windows
 164 -------
 165
 166 You need to run the CMake commands from the Visual Studio command
 167 prompt, not the regular or Windows SDK one. Select the right generator
 168 for your version with the `-G "Visual Studio X" option.
 169
 170 See [the website](http://libgit2.github.com/docs/guides/build-and-link/)
 171 for more detailed instructions.
 172
 173 Android
 174 -------
 175
 176 Extract toolchain from NDK using, `make-standalone-toolchain.sh` script.
 177 Optionally, crosscompile and install OpenSSL inside of it. Then create CMake
 178 toolchain file that configures paths to your crosscompiler (substitute `{PATH}`
 179 with full path to the toolchain):
 180
 181         SET(CMAKE_SYSTEM_NAME Linux)
 182         SET(CMAKE_SYSTEM_VERSION Android)
 183
 184         SET(CMAKE_C_COMPILER   {PATH}/bin/arm-linux-androideabi-gcc)
 185         SET(CMAKE_CXX_COMPILER {PATH}/bin/arm-linux-androideabi-g++)
 186         SET(CMAKE_FIND_ROOT_PATH {PATH}/sysroot/)
 187
 188         SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 189         SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 190         SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 191
 192 Add `-DCMAKE_TOOLCHAIN_FILE={pathToToolchainFile}` to cmake command
 193 when configuring.
 194
 195 Language Bindings
 196 ==================================
 197
 198 Here are the bindings to libgit2 that are currently available:
 199
 200 * C++
 201     * libqgit2, Qt bindings <https://projects.kde.org/projects/playground/libs/libqgit2/repository/>
 202 * Chicken Scheme
 203     * chicken-git <https://wiki.call-cc.org/egg/git>
 204 * D
 205     * dlibgit <https://github.com/s-ludwig/dlibgit>
 206 * Delphi
 207     * GitForDelphi <https://github.com/libgit2/GitForDelphi>
 208 * Erlang
 209     * Geef <https://github.com/carlosmn/geef>
 210 * Go
 211     * git2go <https://github.com/libgit2/git2go>
 212 * GObject
 213     * libgit2-glib <https://wiki.gnome.org/Projects/Libgit2-glib>
 214 * Haskell
 215     * hgit2 <https://github.com/jwiegley/gitlib>
 216 * Java
 217     * Jagged <https://github.com/ethomson/jagged>
 218 * Julia
 219     * LibGit2.jl <https://github.com/jakebolewski/LibGit2.jl>
 220 * Lua
 221     * luagit2 <https://github.com/libgit2/luagit2>
 222 * .NET
 223     * libgit2sharp <https://github.com/libgit2/libgit2sharp>
 224 * Node.js
 225     * nodegit <https://github.com/nodegit/nodegit>
 226 * Objective-C
 227     * objective-git <https://github.com/libgit2/objective-git>
 228 * OCaml
 229     * ocaml-libgit2 <https://github.com/fxfactorial/ocaml-libgit2>
 230 * Parrot Virtual Machine
 231     * parrot-libgit2 <https://github.com/letolabs/parrot-libgit2>
 232 * Perl
 233     * Git-Raw <https://github.com/jacquesg/p5-Git-Raw>
 234 * PHP
 235     * php-git <https://github.com/libgit2/php-git>
 236 * PowerShell
 237     * PSGit <https://github.com/PoshCode/PSGit>
 238 * Python
 239     * pygit2 <https://github.com/libgit2/pygit2>
 240 * R
 241     * git2r <https://github.com/ropensci/git2r>
 242 * Ruby
 243     * Rugged <https://github.com/libgit2/rugged>
 244 * Rust
 245     * git2-rs <https://github.com/alexcrichton/git2-rs>
 246 * Swift
 247     * SwiftGit2 <https://github.com/SwiftGit2/SwiftGit2>
 248 * Vala
 249     * libgit2.vapi <https://github.com/apmasell/vapis/blob/master/libgit2.vapi>
 250
 251 If you start another language binding to libgit2, please let us know so
 252 we can add it to the list.
 253
 254 How Can I Contribute?
 255 ==================================
 256
 257 We welcome new contributors!  We have a number of issues marked as
 258 ["up for grabs"](https://github.com/libgit2/libgit2/issues?q=is%3Aissue+is%3Aopen+label%3A%22up+for+grabs%22)
 259 and
 260 ["easy fix"](https://github.com/libgit2/libgit2/issues?utf8=✓&q=is%3Aissue+is%3Aopen+label%3A%22easy+fix%22)
 261 that are good places to jump in and get started.  There's much more detailed
 262 information in our list of [outstanding projects](PROJECTS.md).
 263
 264 Please be sure to check the [contribution guidelines](CONTRIBUTING.md) to
 265 understand our workflow, and the libgit2 [coding conventions](CONVENTIONS.md).
 266
 267 License
 268 ==================================
 269
 270 `libgit2` is under GPL2 **with linking exception**. This means you can link to
 271 and use the library from any program, proprietary or open source; paid or
 272 gratis.  However, if you modify libgit2 itself, you must distribute the
 273 source to your modified version of libgit2.
 274
 275 See the [COPYING file](COPYING) for the full license text.