]>
Commit | Line | Data |
---|---|---|
530e741c JH |
1 | builtin API |
2 | =========== | |
3 | ||
4 | Adding a new built-in | |
5 | --------------------- | |
6 | ||
82936f29 | 7 | There are 4 things to do to add a built-in command implementation to |
2de9b711 | 8 | Git: |
530e741c JH |
9 | |
10 | . Define the implementation of the built-in command `foo` with | |
11 | signature: | |
12 | ||
13 | int cmd_foo(int argc, const char **argv, const char *prefix); | |
14 | ||
15 | . Add the external declaration for the function to `builtin.h`. | |
16 | ||
17 | . Add the command to `commands[]` table in `handle_internal_command()`, | |
18 | defined in `git.c`. The entry should look like: | |
19 | ||
20 | { "foo", cmd_foo, <options> }, | |
82936f29 SB |
21 | + |
22 | where options is the bitwise-or of: | |
530e741c JH |
23 | |
24 | `RUN_SETUP`:: | |
25 | ||
2de9b711 | 26 | Make sure there is a Git directory to work on, and if there is a |
530e741c JH |
27 | work tree, chdir to the top of it if the command was invoked |
28 | in a subdirectory. If there is no work tree, no chdir() is | |
29 | done. | |
30 | ||
31 | `USE_PAGER`:: | |
32 | ||
33 | If the standard output is connected to a tty, spawn a pager and | |
34 | feed our output to it. | |
35 | ||
82936f29 SB |
36 | `NEED_WORK_TREE`:: |
37 | ||
38 | Make sure there is a work tree, i.e. the command cannot act | |
39 | on bare repositories. | |
d649048e | 40 | This only makes sense when `RUN_SETUP` is also set. |
82936f29 | 41 | |
530e741c JH |
42 | . Add `builtin-foo.o` to `BUILTIN_OBJS` in `Makefile`. |
43 | ||
44 | Additionally, if `foo` is a new command, there are 3 more things to do: | |
45 | ||
46 | . Add tests to `t/` directory. | |
47 | ||
48 | . Write documentation in `Documentation/git-foo.txt`. | |
49 | ||
82936f29 | 50 | . Add an entry for `git-foo` to `command-list.txt`. |
530e741c | 51 | |
e9e0643f HV |
52 | . Add an entry for `/git-foo` to `.gitignore`. |
53 | ||
530e741c JH |
54 | |
55 | How a built-in is called | |
56 | ------------------------ | |
57 | ||
58 | The implementation `cmd_foo()` takes three parameters, `argc`, `argv, | |
59 | and `prefix`. The first two are similar to what `main()` of a | |
60 | standalone command would be called with. | |
61 | ||
62 | When `RUN_SETUP` is specified in the `commands[]` table, and when you | |
63 | were started from a subdirectory of the work tree, `cmd_foo()` is called | |
64 | after chdir(2) to the top of the work tree, and `prefix` gets the path | |
65 | to the subdirectory the command started from. This allows you to | |
66 | convert a user-supplied pathname (typically relative to that directory) | |
67 | to a pathname relative to the top of the work tree. | |
68 | ||
69 | The return value from `cmd_foo()` becomes the exit status of the | |
70 | command. |