mirror of https://github.com/mpv-player/mpv
148 lines
5.4 KiB
Markdown
148 lines
5.4 KiB
Markdown
How to contribute
|
|
=================
|
|
|
|
General
|
|
-------
|
|
|
|
The main contact for mpv development is IRC, specifically #mpv-player and
|
|
#mpv-player-dev on Freenode.
|
|
|
|
Sending patches
|
|
---------------
|
|
|
|
- Make a github pull request, or send a link to a plaintext patch created with
|
|
``git format-patch``. diffs posted as pastebins (especially if the http link
|
|
returns HTML) just cause extra work for everyone, because they lack commit
|
|
message and authorship information.
|
|
- Write informative commit messages. Use present tense to describe the
|
|
situation with the patch applied, and past tense for the situation before
|
|
the change.
|
|
- The subject line (the first line in a commit message) should contain a
|
|
prefix identifying the sub system, followed by a short description what
|
|
impact this commit has. This subject line shouldn't be longer than 72
|
|
characters, because it messes up the output of many git tools otherwise.
|
|
|
|
For example, you fixed a crash in af_volume.c:
|
|
|
|
Bad: ``fixed the bug (wtf?)``
|
|
Good: ``af_volume: fix crash due to null pointer access``
|
|
|
|
Having a prefix gives context, and is especially useful when trying to find
|
|
a specific change by looking at the history, or when running ``git blame``.
|
|
- The body of the commit message (everything else after the subject line) should
|
|
be as informative as possible and contain everything that isn't obvious. Don't
|
|
hesitate to dump as much information as you can - it doesn't cost you
|
|
anything. Put some effort into it. If someone finds a bug months or years
|
|
later, and finds that it's caused by your commit (even though your commit was
|
|
supposed to fix another bug), it would be bad if there wasn't enough
|
|
information to test the original bug. The old bug might be reintroduced while
|
|
fixing the new bug.
|
|
|
|
The commit message should be wrapped on 72 characters per line, because git
|
|
tools usually do not break text automatically. On the other hand, you do not
|
|
need to break text that would be unnatural to break (like data for test cases,
|
|
or long URLs).
|
|
|
|
Important: put an empty line between the subject line and the commit message.
|
|
If this is missing, it will break display in common git tools.
|
|
- Try to separate cosmetic and functional changes. It's ok to make a few
|
|
additional cosmetic changes in the same file you're working on. But don't do
|
|
something like reformatting a whole file, and hiding an actual functional
|
|
change in the same commit.
|
|
- If you add a new command line option, document it in options.rst. If you
|
|
add a new input property, document it in input.rst.
|
|
|
|
Code formatting
|
|
---------------
|
|
|
|
mpv uses C99 with K&R formatting, with some exceptions.
|
|
|
|
- Use the K&R indent style.
|
|
- Use 4 spaces of indentation, never use tabs (except in Makefiles).
|
|
- Add a single space between keywords and binary operators. There are some other
|
|
cases where spaces should be added. Example:
|
|
|
|
```C
|
|
if ((a * b) > c) {
|
|
// code
|
|
some_function(a, b, c);
|
|
}
|
|
```
|
|
- Break lines on 80 columns. There is a hard limit of 85 columns. You may ignore
|
|
this limit if there's a strong case that not breaking the line will increase
|
|
readability. Going over 85 columns might provoke endless discussions about
|
|
whether such a limit is needed or not, so avoid it.
|
|
- If the body of an if/for/while statement has more than 1 physical lines, then
|
|
always add braces, even if they're technically redundant.
|
|
|
|
Bad:
|
|
|
|
```C
|
|
if (a)
|
|
// do something if b
|
|
if (b)
|
|
do_something();
|
|
```
|
|
|
|
Good:
|
|
|
|
```C
|
|
if (a) {
|
|
// do something if b
|
|
if (b)
|
|
do_something();
|
|
}
|
|
```
|
|
- If the body of an if statement uses braces, the else branch should also
|
|
use braces (and reverse).
|
|
|
|
Example:
|
|
|
|
```C
|
|
if (a) {
|
|
// do something
|
|
something();
|
|
something_else();
|
|
} else {
|
|
one_line();
|
|
}
|
|
```
|
|
- If an if condition spans multiple physical lines, then put the opening brace
|
|
for the if body on the next physical line. (Also, preferably always add a
|
|
brace, even if technically none is needed.)
|
|
|
|
Example:
|
|
|
|
```C
|
|
if (very_long_condition_a &&
|
|
very_long_condition_b)
|
|
{
|
|
code();
|
|
}
|
|
```
|
|
- Remove any trailing whitespace.
|
|
- If the file you're editing uses formatting different from from what is
|
|
described here, it's probably an old file from times when nobody followed a
|
|
consistent style. You're free to use the existing style, or the new style, or
|
|
to send a patch to reformat the file to the new style before making functional
|
|
changes.
|
|
|
|
General coding
|
|
--------------
|
|
|
|
- Use C99. Also freely make use of C99 features if it's appropriate, such as
|
|
stdbool.h.
|
|
- Don't use GNU-only features. In some cases they may be warranted, if they
|
|
are optional (such as attributes enabling printf-like format string checks).
|
|
But in general, standard C99 should be used.
|
|
- The same applies to libc functions. We have to be Windows-compatible too. Use
|
|
functions guaranteed by C99 or POSIX only, unless your use is guarded by a
|
|
configure check.
|
|
- Prefer fusing declaration and initialization, rather than putting declarations
|
|
on the top of a block. Obvious data flow is more important than avoiding
|
|
mixing declarations and statements, which is just a C90 artifact.
|
|
- tech-overview.txt might help to get an overview how mpv is structured.
|
|
- If you add features that require intrusive changes, discuss them on the dev
|
|
channel first. There might be a better way to add a feature and it can avoid
|
|
wasted work.
|