asciidoc: add simple asciidoc package

FindAsciidoc.cmake

@@ -0,0 +1,76 @@
+cmake_minimum_required (VERSION 3.7)
+
+find_program(ASCIIDOC NAMES asciidoc DOC "path to the asciidoc binary")
+mark_as_advanced (ASCIIDOC)
+
+if (ASCIIDOC)
+    execute_process (
+        COMMAND ${ASCIIDOC} --version
+        OUTPUT_VARIABLE ASCIIDOC_version_output
+        ERROR_VARIABLE  ASCIIDOC_version_error
+        RESULT_VARIABLE ASCIIDOC_version_result
+    )
+
+    if (${ASCIIDOC_version_output})
+        string (
+            REGEX REPLACE
+            "^asciidoc (\\d+\\.\\d+\\.\\d+)$"
+            "\\1"
+            ASCIIDOC_VERSION
+            "${ASCIIDOC_version_output}"
+        )
+    endif ()
+
+    set (ASCIIDOC_target_usage "ASCIIDOC_target(<name> SOURCE <source> OUTPUT <output> [DEPENDS ...])")
+
+    macro (ASCIIDOC_target name)
+        set (_ASCIIDOC_${name}_onoff_args HTML5)
+        set (_ASCIIDOC_${name}_value_args SOURCE OUTPUT)
+        set (_ASCIIDOC_${name}_multi_args DEPENDS)
+
+        cmake_parse_arguments (_ASCIIDOC_${name}
+            "${_ASCIIDOC_${name}_onoff_args}"
+            "${_ASCIIDOC_${name}_value_args}"
+            "${_ASCIIDOC_${name}_multi_args}"
+            ${ARGN}
+        )
+
+        if (NOT _ASCIIDOC_${name}_SOURCE)
+            message (FATAL_ERROR "${ASCIIDOC_target_usage}")
+        endif ()
+
+        if (NOT _ASCIIDOC_${name}_OUTPUT)
+            message (FATAL_ERROR "${ASCIIDOC_target_usage}")
+        endif ()
+
+        get_filename_component (dir "${_ASCIIDOC_${name}_OUTPUT}" DIRECTORY)
+        file (MAKE_DIRECTORY "${dir}")
+
+        add_custom_command (
+        OUTPUT
+            "${_ASCIIDOC_${name}_OUTPUT}"
+        COMMAND
+            "${ASCIIDOC}" 
+            -b html5
+            -o "${_ASCIIDOC_${name}_OUTPUT}"
+            --theme=volnitsky
+            -a icons
+            "${_ASCIIDOC_${name}_SOURCE}"
+        DEPENDS
+            "${_ASCIIDOC_${name}_SOURCE};${_ASCIIDOC_${name}_DEPENDS}"
+        MAIN_DEPENDENCY
+            "${_ASCIIDOC_${name}_SOURCE}"
+        COMMENT
+            "[asciidoc] ${_ASCIIDOC_${name}_SOURCE}"
+        )
+
+        add_custom_target (${name} "${_ASCIIDOC_${name}_OUTPUT}")
+    endmacro ()
+endif ()
+
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args (ASCIIDOC
+    REQUIRED_VARS  ASCIIDOC
+    VERSION_VAR    ASCIIDOC_VERSION
+)