Add support for generating vapi files for Vala

Author: AdrianVovk

README.md

@@ -30,17 +30,19 @@ Layer shell __is not supported__ on:
 * [GTK3](https://www.gtk.org/) (>=3.22.0)
 * [GObject introspection](https://gitlab.gnome.org/GNOME/gobject-introspection/)
 * [GTK Doc](https://www.gtk.org/gtk-doc/) (only required if docs are enabled)
+* [Vala](https://wiki.gnome.org/Projects/Vala) (only required if vapi is enabled)
 
 To install these dependencies on Ubuntu 18.04 and later:
 ```
-sudo apt install meson libwayland-dev libgtk-3-dev gobject-introspection libgirepository1.0-dev gtk-doc-tools
+sudo apt install meson libwayland-dev libgtk-3-dev gobject-introspection libgirepository1.0-dev gtk-doc-tools valac
 ```
 
 ### Meson Options
 * `-Dexamples` (default `false`): If to build the example C apps; gtk-layer-demo is installed if examples are built; The Vala example is never built with the rest of the project
 * `-Ddocs` (default `false`): If to generate the docs
 * `-Dtests` (default `false`): If to build the tests
 * `-Dintrospection` (default: `true`): If to build GObject Introspection data (used for bindings to langauges other than C/C++)
+* `-Dvapi` (default: `false`): If to build VAPI data (allows this library to be used in Vala). Requires `-Dintrospection=true`
 
 ### Running the Tests
 * `ninja -C build test`

examples/vala-standalone/meson.build

@@ -4,10 +4,10 @@ project('vala-gtk-layer-shell-example',
     license: 'MIT',
     meson_version: '>=0.45.1')
 
+gtk = dependency('gtk+-3.0')
+gtk_layer_shell = dependency('gtk-layer-shell-0')
+
 executable(
     'vala-layer-shell',
     files('main.vala'),
-    vala_args: ['--pkg=GtkLayerShell-0.1'],
-    dependencies: [
-        dependency('gtk+-3.0'),
-        meson.get_compiler('c').find_library('gtk-layer-shell')])
+    dependencies: [ gtk, gtk_layer_shell ])

meson_options.txt

@@ -2,3 +2,4 @@ option('examples', type: 'boolean', value: false, description: 'Build example ap
 option('docs', type: 'boolean', value: false, description: 'Build devhelp API documentation')
 option('tests', type: 'boolean', value: false, description: 'Build tests')
 option('introspection', type: 'boolean', value: true, description: 'Build gobject-introspection data')
+option('vapi', type: 'boolean', value: true, description: 'Generate vapi data (needs vapigen & introspection option)')

src/meson.build

@@ -39,6 +39,14 @@ if get_option('introspection')
         includes: [ 'Gtk-3.0' ],
         header: 'gtk-layer-shell/gtk-layer-shell.h',
         install: true)
+
+    if get_option('vapi')
+        gnome.generate_vapi(
+            pkg_config_name,
+            sources: gir[0],
+            packages: 'gtk+-3.0',
+            install: true)
+    endif
 endif
 
 pkg_config.generate(