CI: Build and deploy documentations

A first step towards better documentations of Mutter
and it internal libraries

.gitlab-ci.yml

@@ -9,6 +9,7 @@ stages:
  - build
  - test
  - analyze
+ - docs
  - deploy
 
 variables:
@@ -485,3 +486,32 @@ dist-mutter-tarball:
       - build/meson-dist/$CI_PROJECT_NAME-$CI_COMMIT_TAG.tar.xz
   rules:
     - if: '$CI_COMMIT_TAG'
+
+reference:
+  extends:
+    - .fdo.distribution-image@fedora
+    - .mutter.fedora:35@x86_64
+  stage: docs
+  needs:
+    - build-fedora-container@x86_64
+  before_script:
+    - dnf install gi-docgen -y
+  script:
+    - meson . build --werror -Ddocs=true -Dtests=false
+    - ninja -C build
+    - mkdir references
+    - mv build/doc/reference/{cally/cally,clutter/clutter,cogl/cogl,cogl-pango/cogl-pango,meta/meta} references/
+  artifacts:
+    paths:
+      - references
+
+pages:
+  stage: deploy
+  needs: ['reference']
+  script:
+    - mv references public/
+  artifacts:
+    paths:
+      - public
+  only:
+    - main