README.md

   1 libgit2 - the Git linkable library
   2 ==================================
   3
   4 | Build Status | |
   5 | ------------ | - |
   6 | **master** branch CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=master)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=master)   |
   7 | **v0.99 branch** CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=maint/v0.99)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=maint/v0.99) |
   8 | **v0.28 branch** CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=maint/v0.28)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=maint/v0.28) |
   9 | **Nightly** builds | [![Azure Pipelines Build Status](https://libgit2.visualstudio.com/libgit2/_apis/build/status/nightly?branchName=master&label=Full+Build)](https://libgit2.visualstudio.com/libgit2/_build/latest?definitionId=9&branchName=master) [![Coverity Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/coverity?branchName=master&label=Coverity+Build)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=21?branchName=master) [![Coverity Scan Build Status](https://scan.coverity.com/projects/639/badge.svg)](https://scan.coverity.com/projects/639) |
  10
  11 `libgit2` is a portable, pure C implementation of the Git core methods
  12 provided as a linkable library with a solid API, allowing to build Git
  13 functionality into your application.  Language bindings like
  14 [Rugged](https://github.com/libgit2/rugged) (Ruby),
  15 [LibGit2Sharp](https://github.com/libgit2/libgit2sharp) (.NET),
  16 [pygit2](http://www.pygit2.org/) (Python) and
  17 [NodeGit](http://nodegit.org) (Node) allow you to build Git tooling
  18 in your favorite language.
  19
  20 `libgit2` is used to power Git GUI clients like
  21 [GitKraken](https://gitkraken.com/) and [gmaster](https://gmaster.io/)
  22 and on Git hosting providers like [GitHub](https://github.com/),
  23 [GitLab](https://gitlab.com/) and
  24 [Azure DevOps](https://azure.com/devops).
  25 We perform the merge every time you click "merge pull request".
  26
  27 `libgit2` is licensed under a **very permissive license** (GPLv2 with a special
  28 Linking Exception).  This basically means that you can link it (unmodified)
  29 with any kind of software without having to release its source code.
  30 Additionally, the example code has been released to the public domain (see the
  31 [separate license](examples/COPYING) for more information).
  32
  33 Table of Contents
  34 =================
  35
  36 * [Quick Start](#quick-start)
  37 * [Getting Help](#getting-help)
  38 * [What It Can Do](#what-it-can-do)
  39 * [Optional dependencies](#optional-dependencies)
  40 * [Initialization](#initialization)
  41 * [Threading](#threading)
  42 * [Conventions](#conventions)
  43 * [Building libgit2 - Using CMake](#building-libgit2---using-cmake)
  44     * [Building](#building)
  45     * [Installation](#installation)
  46     * [Advanced Usage](#advanced-usage)
  47     * [Compiler and linker options](#compiler-and-linker-options)
  48     * [MacOS X](#macos-x)
  49     * [Android](#android)
  50 * [Language Bindings](#language-bindings)
  51 * [How Can I Contribute?](#how-can-i-contribute)
  52 * [License](#license)
  53
  54 Quick Start
  55 ===========
  56
  57 **Prerequisites** for building libgit2:
  58
  59 1. [CMake](https://cmake.org/), and is recommended to be installed into
  60    your `PATH`.
  61 2. [Python](https://www.python.org) is used by our test framework, and
  62    should be installed into your `PATH`.
  63 3. C compiler: libgit2 is C90 and should compile on most compilers.
  64    * Windows: Visual Studio is recommended
  65    * Mac: Xcode is recommended
  66    * Unix: gcc or clang is recommended.
  67
  68 **Build**
  69
  70 1. Create a build directory beneath the libgit2 source directory, and change
  71    into it: `mkdir build && cd build`
  72 2. Create the cmake build environment: `cmake ..`
  73 3. Build libgit2: `cmake --build .`
  74
  75 Trouble with these steps?  Read our [troubleshooting guide](docs/troubleshooting.md).
  76 More detailed build guidance is available below.
  77
  78 Getting Help
  79 ============
  80
  81 **Chat with us**
  82
  83 - via IRC: join [#libgit2](https://webchat.freenode.net/#libgit2) on Freenode
  84 - via Slack: visit [slack.libgit2.org](http://slack.libgit2.org/) to sign up,
  85   then join us in `#libgit2`
  86
  87 **Getting Help**
  88
  89 If you have questions about the library, please be sure to check out the
  90 [API documentation](http://libgit2.github.com/libgit2/).  If you still have
  91 questions, reach out to us on Slack or post a question on
  92 [StackOverflow](http://stackoverflow.com/questions/tagged/libgit2) (with the `libgit2` tag).
  93
  94 **Reporting Bugs**
  95
  96 Please open a [GitHub Issue](https://github.com/libgit2/libgit2/issues) and
  97 include as much information as possible.  If possible, provide sample code
  98 that illustrates the problem you're seeing.  If you're seeing a bug only
  99 on a specific repository, please provide a link to it if possible.
 100
 101 We ask that you not open a GitHub Issue for help, only for bug reports.
 102
 103 **Reporting Security Issues**
 104
 105 Please have a look at SECURITY.md.
 106
 107 What It Can Do
 108 ==============
 109
 110 libgit2 provides you with the ability to manage Git repositories in the
 111 programming language of your choice.  It's used in production to power many
 112 applications including GitHub.com, Plastic SCM and Azure DevOps.
 113
 114 It does not aim to replace the git tool or its user-facing commands. Some APIs
 115 resemble the plumbing commands as those align closely with the concepts of the
 116 Git system, but most commands a user would type are out of scope for this
 117 library to implement directly.
 118
 119 The library provides:
 120
 121 * SHA conversions, formatting and shortening
 122 * abstracted ODB backend system
 123 * commit, tag, tree and blob parsing, editing, and write-back
 124 * tree traversal
 125 * revision walking
 126 * index file (staging area) manipulation
 127 * reference management (including packed references)
 128 * config file management
 129 * high level repository management
 130 * thread safety and reentrancy
 131 * descriptive and detailed error messages
 132 * ...and more (over 175 different API calls)
 133
 134 As libgit2 is purely a consumer of the Git system, we have to
 135 adjust to changes made upstream. This has two major consequences:
 136
 137 * Some changes may require us to change provided interfaces. While we try to
 138   implement functions in a generic way so that no future changes are required,
 139   we cannot promise a completely stable API.
 140 * As we have to keep up with changes in behavior made upstream, we may lag
 141   behind in some areas. We usually to document these incompatibilities in our
 142   issue tracker with the label "git change".
 143
 144 Optional dependencies
 145 =====================
 146
 147 While the library provides git functionality without the need for
 148 dependencies, it can make use of a few libraries to add to it:
 149
 150 - pthreads (non-Windows) to enable threadsafe access as well as multi-threaded pack generation
 151 - OpenSSL (non-Windows) to talk over HTTPS and provide the SHA-1 functions
 152 - LibSSH2 to enable the SSH transport
 153 - iconv (OSX) to handle the HFS+ path encoding peculiarities
 154
 155 Initialization
 156 ===============
 157
 158 The library needs to keep track of some global state. Call
 159
 160     git_libgit2_init();
 161
 162 before calling any other libgit2 functions. You can call this function many times. A matching number of calls to
 163
 164     git_libgit2_shutdown();
 165
 166 will free the resources.  Note that if you have worker threads, you should
 167 call `git_libgit2_shutdown` *after* those threads have exited.  If you
 168 require assistance coordinating this, simply have the worker threads call
 169 `git_libgit2_init` at startup and `git_libgit2_shutdown` at shutdown.
 170
 171 Threading
 172 =========
 173
 174 See [threading](docs/threading.md) for information
 175
 176 Conventions
 177 ===========
 178
 179 See [conventions](docs/conventions.md) for an overview of the external
 180 and internal API/coding conventions we use.
 181
 182 Building libgit2 - Using CMake
 183 ==============================
 184
 185 Building
 186 --------
 187
 188 `libgit2` builds cleanly on most platforms without any external dependencies.
 189 Under Unix-like systems, like Linux, \*BSD and Mac OS X, libgit2 expects `pthreads` to be available;
 190 they should be installed by default on all systems. Under Windows, libgit2 uses the native Windows API
 191 for threading.
 192
 193 The `libgit2` library is built using [CMake](<https://cmake.org/>) (version 2.8 or newer) on all platforms.
 194
 195 On most systems you can build the library using the following commands
 196
 197         $ mkdir build && cd build
 198         $ cmake ..
 199         $ cmake --build .
 200
 201 Alternatively you can point the CMake GUI tool to the CMakeLists.txt file and generate platform specific build project or IDE workspace.
 202
 203 Running Tests
 204 -------------
 205
 206 Once built, you can run the tests from the `build` directory with the command
 207
 208         $ ctest -V
 209
 210 Alternatively you can run the test suite directly using,
 211
 212         $ ./libgit2_clar
 213
 214 Invoking the test suite directly is useful because it allows you to execute
 215 individual tests, or groups of tests using the `-s` flag.  For example, to
 216 run the index tests:
 217
 218     $ ./libgit2_clar -sindex
 219
 220 To run a single test named `index::racy::diff`, which corresponds to the test
 221 function [`test_index_racy__diff`](https://github.com/libgit2/libgit2/blob/master/tests/index/racy.c#L23):
 222
 223     $ ./libgit2_clar -sindex::racy::diff
 224
 225 The test suite will print a `.` for every passing test, and an `F` for any
 226 failing test.  An `S` indicates that a test was skipped because it is not
 227 applicable to your platform or is particularly expensive.
 228
 229 **Note:** There should be _no_ failing tests when you build an unmodified
 230 source tree from a [release](https://github.com/libgit2/libgit2/releases),
 231 or from the [master branch](https://github.com/libgit2/libgit2/tree/master).
 232 Please contact us or [open an issue](https://github.com/libgit2/libgit2/issues)
 233 if you see test failures.
 234
 235 Installation
 236 ------------
 237
 238 To install the library you can specify the install prefix by setting:
 239
 240         $ cmake .. -DCMAKE_INSTALL_PREFIX=/install/prefix
 241         $ cmake --build . --target install
 242
 243 Advanced Usage
 244 --------------
 245
 246 For more advanced use or questions about CMake please read <https://cmake.org/Wiki/CMake_FAQ>.
 247
 248 The following CMake variables are declared:
 249
 250 - `CMAKE_INSTALL_BINDIR`: Where to install binaries to.
 251 - `CMAKE_INSTALL_LIBDIR`: Where to install libraries to.
 252 - `CMAKE_INSTALL_INCLUDEDIR`: Where to install headers to.
 253 - `BUILD_SHARED_LIBS`: Build libgit2 as a Shared Library (defaults to ON)
 254 - `BUILD_CLAR`: Build [Clar](https://github.com/vmg/clar)-based test suite (defaults to ON)
 255 - `THREADSAFE`: Build libgit2 with threading support (defaults to ON)
 256
 257 To list all build options and their current value, you can do the
 258 following:
 259
 260         # Create and set up a build directory
 261         $ mkdir build
 262         $ cmake ..
 263         # List all build options and their values
 264         $ cmake -L
 265
 266 Compiler and linker options
 267 ---------------------------
 268
 269 CMake lets you specify a few variables to control the behavior of the
 270 compiler and linker. These flags are rarely used but can be useful for
 271 64-bit to 32-bit cross-compilation.
 272
 273 - `CMAKE_C_FLAGS`: Set your own compiler flags
 274 - `CMAKE_FIND_ROOT_PATH`: Override the search path for libraries
 275 - `ZLIB_LIBRARY`, `OPENSSL_SSL_LIBRARY` AND `OPENSSL_CRYPTO_LIBRARY`:
 276 Tell CMake where to find those specific libraries
 277
 278 MacOS X
 279 -------
 280
 281 If you want to build a universal binary for Mac OS X, CMake sets it
 282 all up for you if you use `-DCMAKE_OSX_ARCHITECTURES="i386;x86_64"`
 283 when configuring.
 284
 285 Android
 286 -------
 287
 288 Extract toolchain from NDK using, `make-standalone-toolchain.sh` script.
 289 Optionally, crosscompile and install OpenSSL inside of it. Then create CMake
 290 toolchain file that configures paths to your crosscompiler (substitute `{PATH}`
 291 with full path to the toolchain):
 292
 293         SET(CMAKE_SYSTEM_NAME Linux)
 294         SET(CMAKE_SYSTEM_VERSION Android)
 295
 296         SET(CMAKE_C_COMPILER   {PATH}/bin/arm-linux-androideabi-gcc)
 297         SET(CMAKE_CXX_COMPILER {PATH}/bin/arm-linux-androideabi-g++)
 298         SET(CMAKE_FIND_ROOT_PATH {PATH}/sysroot/)
 299
 300         SET(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 301         SET(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
 302         SET(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 303
 304 Add `-DCMAKE_TOOLCHAIN_FILE={pathToToolchainFile}` to cmake command
 305 when configuring.
 306
 307 Language Bindings
 308 ==================================
 309
 310 Here are the bindings to libgit2 that are currently available:
 311
 312 * C++
 313     * libqgit2, Qt bindings <https://projects.kde.org/projects/playground/libs/libqgit2/repository/>
 314 * Chicken Scheme
 315     * chicken-git <https://wiki.call-cc.org/egg/git>
 316 * D
 317     * dlibgit <https://github.com/s-ludwig/dlibgit>
 318 * Delphi
 319     * GitForDelphi <https://github.com/libgit2/GitForDelphi>
 320 * Erlang
 321     * Geef <https://github.com/carlosmn/geef>
 322 * Go
 323     * git2go <https://github.com/libgit2/git2go>
 324 * GObject
 325     * libgit2-glib <https://wiki.gnome.org/Projects/Libgit2-glib>
 326 * Guile
 327         * Guile-Git <https://gitlab.com/guile-git/guile-git>
 328 * Haskell
 329     * hgit2 <https://github.com/jwiegley/gitlib>
 330 * Java
 331     * Jagged <https://github.com/ethomson/jagged>
 332 * Javascript / WebAssembly ( browser and nodejs )
 333     * WASM-git <https://github.com/petersalomonsen/wasm-git>
 334 * Julia
 335     * LibGit2.jl <https://github.com/JuliaLang/julia/tree/master/stdlib/LibGit2>
 336 * Lua
 337     * luagit2 <https://github.com/libgit2/luagit2>
 338 * .NET
 339     * libgit2sharp <https://github.com/libgit2/libgit2sharp>
 340 * Node.js
 341     * nodegit <https://github.com/nodegit/nodegit>
 342 * Objective-C
 343     * objective-git <https://github.com/libgit2/objective-git>
 344 * OCaml
 345     * ocaml-libgit2 <https://github.com/fxfactorial/ocaml-libgit2>
 346 * Parrot Virtual Machine
 347     * parrot-libgit2 <https://github.com/letolabs/parrot-libgit2>
 348 * Perl
 349     * Git-Raw <https://github.com/jacquesg/p5-Git-Raw>
 350 * PHP
 351     * php-git <https://github.com/libgit2/php-git>
 352 * PowerShell
 353     * PSGit <https://github.com/PoshCode/PSGit>
 354 * Python
 355     * pygit2 <https://github.com/libgit2/pygit2>
 356 * R
 357     * git2r <https://github.com/ropensci/git2r>
 358 * Ruby
 359     * Rugged <https://github.com/libgit2/rugged>
 360 * Rust
 361     * git2-rs <https://github.com/rust-lang/git2-rs>
 362 * Swift
 363     * SwiftGit2 <https://github.com/SwiftGit2/SwiftGit2>
 364 * Vala
 365     * libgit2.vapi <https://github.com/apmasell/vapis/blob/master/libgit2.vapi>
 366
 367 If you start another language binding to libgit2, please let us know so
 368 we can add it to the list.
 369
 370 How Can I Contribute?
 371 ==================================
 372
 373 We welcome new contributors!  We have a number of issues marked as
 374 ["up for grabs"](https://github.com/libgit2/libgit2/issues?q=is%3Aissue+is%3Aopen+label%3A%22up+for+grabs%22)
 375 and
 376 ["easy fix"](https://github.com/libgit2/libgit2/issues?utf8=✓&q=is%3Aissue+is%3Aopen+label%3A%22easy+fix%22)
 377 that are good places to jump in and get started.  There's much more detailed
 378 information in our list of [outstanding projects](docs/projects.md).
 379
 380 Please be sure to check the [contribution guidelines](docs/contributing.md) to
 381 understand our workflow, and the libgit2 [coding conventions](docs/conventions.md).
 382
 383 License
 384 ==================================
 385
 386 `libgit2` is under GPL2 **with linking exception**. This means you can link to
 387 and use the library from any program, proprietary or open source; paid or
 388 gratis.  However, if you modify libgit2 itself, you must distribute the
 389 source to your modified version of libgit2.
 390
 391 See the [COPYING file](COPYING) for the full license text.