# gst-build

GStreamer [meson](http://mesonbuild.com/) based repositories aggregrator

You can build GStreamer and all its modules at once using
meson and its [subproject](https://github.com/mesonbuild/meson/wiki/Subprojects) feature.

## Getting started

### Install meson and ninja

You should get meson through your package manager or using:

  $ pip3 install --user meson

If you are building on Windows, do not use the Meson MSI installer since it is
experimental and will likely not work.

You should get `ninja` using your package manager or download the [official
release](https://github.com/ninja-build/ninja/releases) and put it in your PATH.

### Build GStreamer and its modules

You can get all GStreamer built running:

```
mkdir build/ && meson build && ninja -C build/
```

NOTE: on fedora (and maybe other distributions) replace `ninja` with `ninja-build`

# Development environment

## Uninstalled environment

gst-build also contains a special `uninstalled` target that lets you enter an
uninstalled development environment where you will be able to work on GStreamer
easily. You can get into that environment running:

```
ninja -C build/ uninstalled
```

If your operating system handles symlinks, built modules source code will be
available at the root of `gst-build/` for example GStreamer core will be in
`gstreamer/`. Otherwise they will be present in `subprojects/`. You can simply
hack in there and to rebuild you just need to rerun `ninja -C build/`.

NOTE: In the uninstalled environment, a fully usable prefix is also configured
in `gst-build/prefix` where you can install any extra dependency/project.

## Update git subprojects

We added a special `update` target to update subprojects (it uses `git pull
--rebase` meaning you should always make sure the branches you work on are
following the right upstream branch, you can set it with `git branch
--set-upstream-to origin/master` if you are working on `gst-build` master
branch).

Update all GStreamer modules and rebuild:

```
ninja -C build/ update
```

Update all GStreamer modules without rebuilding:

```
ninja -C build/ git-update
```

## Custom subprojects

We also added a meson option, 'custom_subprojects', that allows the user
to provide a comma-separated list of subprojects that should be built
alongside the default ones.

To use it:

```
cd subprojects
git clone my_subproject
cd ../build
rm -rf * && meson .. -Dcustom_subprojects=my_subproject
ninja
```


## Run tests

You can easily run the test of all the components:

```
meson test -C build
```

To list all available tests:

```
meson test -C build --list
```

To run all the tests of a specific component:

```
meson test -C build --suite gst-plugins-base
```

Or to run a specific test file:

```
meson test -C build/ --suite gstreamer gst_gstbuffer
```

Run a specific test from a specific test file:

```
GST_CHECKS=test_subbuffer meson test -C build/ --suite gstreamer gst_gstbuffer
```

## Checkout another branch using worktrees

If you need to have several versions of GStreamer coexisting (eg. `master` and `1.14`),
you can use the `checkout-branch-worktree` script provided by `gst-build`. It allows you
to create a new `gst-build` environment with new checkout of all the GStreamer modules as
[git worktrees](https://git-scm.com/docs/git-worktree).

For example to get a fresh checkout of `gst-1.14` from a `gst-build` in master already
built in a `build` directory you can simply run:

```
./checkout-branch-worktree ../gst-1.14 1.14 -C build/
```

## Add information about GStreamer development environment in your prompt line

### Bash prompt

We automatically handle `bash` and set `$PS1` accordingly.

If the automatic `$PS1` override is not desired (maybe you have a fancy custom prompt), set the `$GST_BUILD_DISABLE_PS1_OVERRIDE` environment variable to `TRUE` and use `$GST_ENV` when setting the custom prompt, for example with a snippet like the following:

```bash
...
if [[ -n "${GST_ENV-}" ]];
then
  PS1+="[ ${GST_ENV} ]"
fi
...

```

### Zsh prompt

In your `.zshrc`, you should add something like:

```
export PROMPT="$GST_ENV-$PROMPT"
```

### Fish prompt

In your `~/.config/fish/functions/fish_prompt.fish`, you should add something like this at the end of the fish_prompt function body:

```
if set -q GST_ENV
  echo -n -s (set_color -b blue white) "(" (basename "$GST_ENV") ")" (set_color normal) " "
end
```

### Using powerline

In your powerline theme configuration file (by default in
`{POWERLINE INSTALLATION DIR}/config_files/themes/shell/default.json`)
you should add a new environment segment as follow:

```
{
  "function": "powerline.segments.common.env.environment",
  "args": { "variable": "GST_ENV" },
  "priority": 50
},
```