Add documentation generation

Signed-off-by: Pierre R. Mai <pmai@pmsf.de>
Signed-off-by: Habedank Clemens <qxs2704@europe.bmw.corp>

Author: pmai

.github/workflows/protobuf.yml

@@ -25,6 +25,9 @@ jobs:
     - name: Install Python Dependencies
       run: python -m pip install --upgrade pip setuptools wheel pyyaml
 
+    - name: Install Doxygen
+      run: sudo apt-get install doxygen graphviz
+
     - name: Cache Dependencies
       id: cache-depends
       uses: actions/cache@v2
@@ -45,12 +48,20 @@ jobs:
       working-directory: protobuf-3.11.3
       run: sudo make install && sudo ldconfig
 
+    - name: Install proto2cpp
+      run: git clone --depth 1 https://github.com/OpenSimulationInterface/proto2cpp.git
+
     - name: Prepare C++ Build
       run: mkdir build
 
+    - name: Prepare Documentation Bukd
+      run: |
+        echo "EXCLUDE_PATTERNS = */osi3/* */protobuf-3.11.3/* */proto2cpp/*" >> doxygen_config.cmake.in
+        echo "GENERATE_TREEVIEW = YES" >> doxygen_config.cmake.in
+
     - name: Configure C++ Build
       working-directory: build
-      run: cmake ..
+      run: cmake -D FILTER_PROTO2CPP_PY_PATH=$GITHUB_WORKSPACE/proto2cpp ..
 
     - name: Build C++
       working-directory: build
@@ -65,3 +76,10 @@ jobs:
     - name: Run Python Tests
       run: python -m unittest discover tests
 
+    - name: Archive Documentation
+      uses: actions/upload-artifact@v2
+      with:
+        name: linux64-doc
+        path: doc/html
+        if-no-files-found: error
+