Added Doxygen support. (#1228)

Signed-off-by: Vitaly Zaitsev <vitaly@easycoding.org>

.github/workflows/doxygen.yml

@@ -0,0 +1,26 @@
+name: doxygen
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  build-and-deploy:
+    name: Build HTML documentation
+    runs-on: ubuntu-latest
+    steps:
+    - name: Fetching sources
+      uses: actions/checkout@v2
+    - name: Installing build dependencies
+      run: |
+        sudo apt update
+        sudo apt install cmake doxygen gcc git
+    - name: Creating build directory
+      run: |
+        mkdir build
+    - name: Building HTML documentation with Doxygen
+      run: |
+        cmake -S . -B build -DBENCHMARK_ENABLE_TESTING:BOOL=OFF -DBENCHMARK_ENABLE_DOXYGEN:BOOL=ON -DBENCHMARK_INSTALL_DOCS:BOOL=ON
+        cmake --build build --target benchmark_doxygen

CMakeLists.txt

@@ -36,6 +36,7 @@ else()
   set(BENCHMARK_BUILD_32_BITS OFF CACHE BOOL "Build a 32 bit version of the library - unsupported when using MSVC)" FORCE)
 endif()
 option(BENCHMARK_ENABLE_INSTALL "Enable installation of benchmark. (Projects embedding benchmark may want to turn this OFF.)" ON)
+option(BENCHMARK_ENABLE_DOXYGEN "Build documentation with Doxygen." OFF)
 option(BENCHMARK_INSTALL_DOCS "Enable installation of documentation." ON)
 
 # Allow unmet dependencies to be met using CMake's ExternalProject mechanics, which

src/CMakeLists.txt

@@ -115,11 +115,39 @@ if (BENCHMARK_ENABLE_INSTALL)
       EXPORT "${targets_export_name}"
       NAMESPACE "${namespace}"
       DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
+endif()
 
+if (BENCHMARK_ENABLE_DOXYGEN)
+  find_package(Doxygen REQUIRED)
+  set(DOXYGEN_QUIET YES)
+  set(DOXYGEN_RECURSIVE YES)
+  set(DOXYGEN_GENERATE_HTML YES)
+  set(DOXYGEN_GENERATE_MAN NO)
+  set(DOXYGEN_MARKDOWN_SUPPORT YES)
+  set(DOXYGEN_BUILTIN_STL_SUPPORT YES)
+  set(DOXYGEN_EXTRACT_PACKAGE YES)
+  set(DOXYGEN_EXTRACT_STATIC YES)
+  set(DOXYGEN_SHOW_INCLUDE_FILES YES)
+  set(DOXYGEN_BINARY_TOC YES)
+  set(DOXYGEN_TOC_EXPAND YES)
+  set(DOXYGEN_USE_MDFILE_AS_MAINPAGE "index.md")
+  doxygen_add_docs(benchmark_doxygen
+    docs
+    include
+    src
+    ALL
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+    COMMENT "Building documentation with Doxygen.")
+  if (BENCHMARK_INSTALL_DOCS)
+    install(
+      DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/html/"
+      DESTINATION ${CMAKE_INSTALL_DOCDIR})
+  endif()
+else()
   if (BENCHMARK_INSTALL_DOCS)
     install(
       DIRECTORY "${PROJECT_SOURCE_DIR}/docs/"
-      DESTINATION "${CMAKE_INSTALL_DOCDIR}")
+      DESTINATION ${CMAKE_INSTALL_DOCDIR})
   endif()
 
   export (EXPORT ${targets_export_name} NAMESPACE "${namespace}"