Docs: Add epub targets for the guides.

Add user_guide_epub and developer_guide_epub targets that generate
EPUB versions of the User's Guide and Developer's Guide.
Ping #17494.

3 files changed, 76 insertions, 1 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index dd2564fafb..bd4e3ca9c3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -414,6 +414,7 @@ Documentation:
     # XXX We might want to move this to wireshark-ubuntu-dev or debian-setup.sh.
     - DEBIAN_FRONTEND=noninteractive apt-get update
     - DEBIAN_FRONTEND=noninteractive apt-get --yes install ruby-coderay ruby-asciidoctor-pdf
+    - NOKOGIRI_USE_SYSTEM_LIBRARIES=1 gem install asciidoctor-epub3
     - mkdir build
     - cd build
     - printf "\e[0Ksection_start:%s:cmake_section[collapsed=true]\r\e[0KRunning CMake" "$( date +%s)"
@@ -425,9 +426,10 @@ Documentation:
   after_script:
     - mv -v build/docbook/ws[ud]g_html{,_chunked}.zip .
     - mv -v build/docbook/{user,developer}-guide.pdf .
+    - mv -v build/docbook/{user,developer}-guide.epub .
     - |
       if [ -n "$AWS_ACCESS_KEY_ID" ] && [ -n "$AWS_SECRET_ACCESS_KEY" ] && [ -n "$S3_DESTINATION_DOCS" ] ; then
-        for DOC_FILE in ws[ud]g_html{,_chunked}.zip {user,developer}-guide.pdf ; do
+        for DOC_FILE in ws[ud]g_html{,_chunked}.zip {user,developer}-guide.pdf {user,developer}-guide.epub ; do
           aws s3 cp "$DOC_FILE" "$S3_DESTINATION_DOCS/"
         done
       fi
@@ -439,6 +441,8 @@ Documentation:
       - wsdg_html_chunked.zip
       - user-guide.pdf
       - developer-guide.pdf
+      - user-guide.epub
+      - developer-guide.epub
   needs: []
 
 
diff --git a/cmake/modules/FindAsciidoctor.cmake b/cmake/modules/FindAsciidoctor.cmake
index a452d4af22..f9d61e5c80 100644
--- a/cmake/modules/FindAsciidoctor.cmake
+++ b/cmake/modules/FindAsciidoctor.cmake
@@ -177,6 +177,53 @@ if(ASCIIDOCTOR_EXECUTABLE)
 
     endif(ASCIIDOCTOR_PDF_EXECUTABLE)
 
+    FIND_PROGRAM(ASCIIDOCTOR_EPUB_EXECUTABLE
+        NAMES
+            asciidoctorj
+            asciidoctor-epub3
+        PATHS
+            /bin
+            /usr/bin
+            /usr/local/bin
+            ${CHOCOLATEY_BIN_PATH}
+        DOC "Path to Asciidoctor EPUB3 or AsciidoctorJ"
+    )
+
+    if(ASCIIDOCTOR_EPUB_EXECUTABLE)
+
+        set(_asciidoctor_epub_common_command
+            ${CMAKE_COMMAND} -E env TZ=UTC ASCIIDOCTORJ_OPTS="${_asciidoctorj_opts}"
+            ${ASCIIDOCTOR_EPUB_EXECUTABLE}
+            --backend epub3
+            ${_asciidoctor_common_args}
+        )
+
+        MACRO(ASCIIDOCTOR2EPUB _asciidocsource)
+            GET_FILENAME_COMPONENT(_source_base_name ${_asciidocsource} NAME_WE )
+            set(_output_epub ${_source_base_name}.epub)
+
+            ADD_CUSTOM_COMMAND(
+            OUTPUT
+                    ${_output_epub}
+            COMMAND ${_asciidoctor_epub_common_command}
+                    --out-file ${_output_epub}
+                    ${CMAKE_CURRENT_SOURCE_DIR}/${_asciidocsource}
+            DEPENDS
+                    ${CMAKE_CURRENT_SOURCE_DIR}/${_asciidocsource}
+                    ${ARGN}
+            )
+            add_custom_target(generate_${_output_epub} DEPENDS ${_output_epub})
+            set_asciidoctor_target_properties(generate_${_output_epub})
+            unset(_output_epub)
+        ENDMACRO()
+
+    else(ASCIIDOCTOR_EPUB_EXECUTABLE)
+
+        MACRO(ASCIIDOCTOR2EPUB _asciidocsource)
+        ENDMACRO()
+
+    endif(ASCIIDOCTOR_EPUB_EXECUTABLE)
+
 endif(ASCIIDOCTOR_EXECUTABLE)
 
 include( FindPackageHandleStandardArgs )
diff --git a/docbook/CMakeLists.txt b/docbook/CMakeLists.txt
index fa4623b0ba..6ae743c4ed 100644
--- a/docbook/CMakeLists.txt
+++ b/docbook/CMakeLists.txt
@@ -396,6 +396,18 @@ if(ASCIIDOCTOR_FOUND AND ASCIIDOCTOR_PDF_EXECUTABLE)
 	add_dependencies(user_guides user_guide_pdf)
 endif()
 
+if(ASCIIDOCTOR_FOUND AND ASCIIDOCTOR_EPUB_EXECUTABLE)
+	ASCIIDOCTOR2EPUB(user-guide.adoc ${WSUG_SOURCE} ${WSUG_BUILT_DEPS})
+
+	add_custom_target(
+		user_guide_epub
+		DEPENDS
+			user-guide.epub
+	)
+	set_docbook_target_properties(user_guide_epub)
+	add_dependencies(user_guides user_guide_epub)
+endif()
+
 # Developer's Guide chain.
 if(ASCIIDOCTOR_FOUND AND XSLTPROC_EXECUTABLE)
 	XML2HTML(
@@ -436,6 +448,18 @@ if(ASCIIDOCTOR_FOUND AND ASCIIDOCTOR_PDF_EXECUTABLE)
 	add_dependencies(developer_guides developer_guide_pdf)
 endif()
 
+if(ASCIIDOCTOR_FOUND AND ASCIIDOCTOR_EPUB_EXECUTABLE)
+	ASCIIDOCTOR2EPUB(developer-guide.adoc ${WSDG_SOURCE} ${WSDG_BUILT_DEPS})
+
+	add_custom_target(
+		developer_guide_epub
+		DEPENDS
+			developer-guide.epub
+	)
+	set_docbook_target_properties(developer_guide_epub)
+	add_dependencies(developer_guides developer_guide_epub)
+endif()
+
 if (GUIDE_INSTALL_DIRS)
 	# The installation location and DOC_DIR in ui/help_url.c must
 	# match.