From aeb7396961b4afcb716cec498ca40fe918c4eb46 Mon Sep 17 00:00:00 2001
From: tastytea <tastytea@tastytea.de>
Date: Fri, 13 Nov 2020 14:25:22 +0100
Subject: [PATCH] Generate API documentation with CMake.

---
 .gitignore          |  1 -
 CMakeLists.txt      |  8 ++++++++
 Doxyfile            | 27 ---------------------------
 README.adoc         |  1 +
 build_doc.sh        | 11 -----------
 cmake/Doxygen.cmake | 43 +++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 52 insertions(+), 39 deletions(-)
 delete mode 100644 Doxyfile
 delete mode 100755 build_doc.sh
 create mode 100644 cmake/Doxygen.cmake

diff --git a/.gitignore b/.gitignore
index 137ea96..cfbfdce 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,3 @@
 /build/
-/doc/
 /update_doc.sh
 /examples/example99*
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e13eedf..5e670c9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,7 @@ list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")
 # Project build options.
 option(WITH_TESTS "Compile tests." NO)
 option(WITH_EXAMPLES "Compile examples." NO)
+option(WITH_DOC "Generate API documentation." NO)
 option(WITH_DEB "Prepare for the building of .deb packages." NO)
 option(WITH_RPM "Prepare for the building of .rpm packages." NO)
 option(WITH_CLANG-TIDY "Check sourcecode with clang-tidy while compiling." NO)
@@ -60,4 +61,11 @@ if(WITH_EXAMPLES)
   add_subdirectory(examples)
 endif()
 
+if(WITH_DOC)
+  include(cmake/Doxygen.cmake)
+  enable_doxygen(
+    "${CMAKE_CURRENT_SOURCE_DIR}/include"
+    "${CMAKE_CURRENT_SOURCE_DIR}/src")
+endif()
+
 include(cmake/packages.cmake)
diff --git a/Doxyfile b/Doxyfile
deleted file mode 100644
index 5484c91..0000000
--- a/Doxyfile
+++ /dev/null
@@ -1,27 +0,0 @@
-# -*- mode: conf-unix -*-
-INPUT                  = src/ include/
-RECURSIVE              = YES
-STRIP_FROM_INC_PATH    = "include"
-EXAMPLE_PATH           = examples/
-EXAMPLE_RECURSIVE      = YES
-GENERATE_HTML          = YES
-HTML_OUTPUT            = doc/html
-GENERATE_LATEX         = NO
-ALLOW_UNICODE_NAMES    = YES
-BRIEF_MEMBER_DESC      = YES
-REPEAT_BRIEF           = YES
-ALWAYS_DETAILED_SEC    = YES
-INLINE_INHERITED_MEMB  = NO
-INHERIT_DOCS           = YES
-SEPARATE_MEMBER_PAGES  = NO
-TAB_SIZE               = 4
-MARKDOWN_SUPPORT       = YES
-AUTOLINK_SUPPORT       = YES
-INLINE_SIMPLE_STRUCTS  = NO
-QUIET                  = NO
-WARNINGS               = YES
-BUILTIN_STL_SUPPORT    = YES
-VERBATIM_HEADERS       = YES
-INLINE_SOURCES         = YES
-SEARCHENGINE           = YES
-SHOW_FILES             = YES
diff --git a/README.adoc b/README.adoc
index 506d6c8..9b5b8df 100644
--- a/README.adoc
+++ b/README.adoc
@@ -151,6 +151,7 @@ cmake --build . -- -j$(nproc --ignore=1)
 * `-DCMAKE_BUILD_TYPE=Debug` for a debug build.
 * `-DWITH_TESTS=YES` if you want to compile the tests.
 * `-DWITH_EXAMPLES=YES` if you want to compile the examples.
+* `-DWITH_DOC=YES` if you want to generate the API documentation.
 * `-DWITH_CLANG-TIDY=YES` to check the sourcecode with
   link:{uri-clang-tidy}[clang-tidy] while compiling.
 * One of:
diff --git a/build_doc.sh b/build_doc.sh
deleted file mode 100755
index 40b1371..0000000
--- a/build_doc.sh
+++ /dev/null
@@ -1,11 +0,0 @@
-#!/bin/sh
-
-project="$(realpath --relative-base=.. .)"
-version="$(grep -Eo '[0-9]+.[0-9]+.[0-9]+$' CMakeLists.txt)"
-
-if [[ -f Doxyfile ]]; then
-    mkdir -p doc
-    (doxygen -s -g - && cat Doxyfile &&
-         echo "PROJECT_NAME = ${project}" &&
-         echo "PROJECT_NUMBER = ${version}") | doxygen -
-fi
diff --git a/cmake/Doxygen.cmake b/cmake/Doxygen.cmake
new file mode 100644
index 0000000..ef0c4e7
--- /dev/null
+++ b/cmake/Doxygen.cmake
@@ -0,0 +1,43 @@
+include(GNUInstallDirs)
+
+function(enable_doxygen)
+  find_package(Doxygen REQUIRED dot)
+
+  set(DOXYGEN_RECURSIVE              YES)
+  set(DOXYGEN_STRIP_FROM_INC_PATH    "include")
+  if (WITH_EXAMPLES)
+    set(DOXYGEN_EXAMPLE_PATH         "examples/")
+    set(DOXYGEN_EXAMPLE_RECURSIVE    YES)
+  endif()
+  set(DOXYGEN_GENERATE_HTML          YES)
+  set(DOXYGEN_HTML_OUTPUT            "doc/html")
+  set(DOXYGEN_GENERATE_LATEX         NO)
+  set(DOXYGEN_ALLOW_UNICODE_NAMES    YES)
+  set(DOXYGEN_BRIEF_MEMBER_DESC      YES)
+  set(DOXYGEN_REPEAT_BRIEF           YES)
+  set(DOXYGEN_ALWAYS_DETAILED_SEC    YES)
+  set(DOXYGEN_INLINE_INHERITED_MEMB  NO)
+  set(DOXYGEN_INHERIT_DOCS           YES)
+  set(DOXYGEN_SEPARATE_MEMBER_PAGES  NO)
+  set(DOXYGEN_TAB_SIZE               4)
+  set(DOXYGEN_MARKDOWN_SUPPORT       YES)
+  set(DOXYGEN_AUTOLINK_SUPPORT       YES)
+  set(DOXYGEN_INLINE_SIMPLE_STRUCTS  NO)
+  set(DOXYGEN_QUIET                  YES)
+  set(DOXYGEN_WARNINGS               YES)
+  set(DOXYGEN_WARN_IF_UNDOCUMENTED   YES)
+  set(DOXYGEN_BUILTIN_STL_SUPPORT    YES)
+  set(DOXYGEN_VERBATIM_HEADERS       YES)
+  set(DOXYGEN_INLINE_SOURCES         YES)
+  set(DOXYGEN_SEARCHENGINE           YES)
+  set(DOXYGEN_SHOW_FILES             YES)
+
+  file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/doc")
+
+  doxygen_add_docs(${PROJECT_NAME}_doxygen "${ARGV}")
+  # Make sure doxygen is run with every build.
+  add_custom_target(${PROJECT_NAME}_docs ALL DEPENDS ${PROJECT_NAME}_doxygen)
+
+  install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/doc/html
+    DESTINATION "${CMAKE_INSTALL_DOCDIR}")
+endfunction()