docs/manual: document the asciidoc infra

[Peter: move periods outside paranthesis as suggested by Thomas De Schampheleire]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Reviewed-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/manual/adding-packages-asciidoc.txt

@@ -0,0 +1,119 @@
+// -*- mode:doc; -*-
+// vim: syntax=asciidoc
+
+=== Infrastructure for asciidoc documents
+
+[[asciidoc-documents-tutorial]]
+
+The Buildroot manual, which you are currently reading, is entirely written
+using the http://asciidoc.org/[AsciiDoc] mark-up syntax. The manual is then
+rendered to many formats:
+
+* html
+* split-html
+* pdf
+* epub
+* text
+
+Although Buildroot only contains one document written in AsciiDoc, there
+is, as for packages, an infrastructure for rendering documents using the
+AsciiDoc syntax.
+
+Also as for packages, the AsciiDoc infrastructure is available from
+xref:outside-br-custom[BR2_EXTERNAL]. This allows documentation for a
+BR2_EXTERNAL tree to match the Buildroot documentation, as it will be
+rendered to the same formats and use the same layout and theme.
+
+==== +asciidoc-document+ tutorial
+
+Whereas package infrastructures are suffixed with +-package+, the document
+infrastructures are suffixed with +-document+. So, the AsciiDoc infrastructure
+is named +asciidoc-document+.
+
+Here is an example to render a simple AsciiDoc document.
+
+----
+01: ################################################################################
+02: #
+03: # foo-document
+04: #
+05: ################################################################################
+06:
+07: FOO_SOURCES = $(sort $(wildcard $(pkgdir)/*))
+08: $(eval $(call asciidoc-document))
+----
+
+On line 7, the Makefile declares what the sources of the document are.
+Currently, it is expected that the document's sources are only local;
+Buildroot will not attempt to download anything to render a document.
+Thus, you must indicate where the sources are. Usually, the string
+above is sufficient for a document with no sub-directory structure.
+
+On line 8, we call the +asciidoc-document+ function, which generates all
+the Makefile code necessary to render the document.
+
+==== +asciidoc-document+ reference
+
+The list of variables that can be set in a +.mk+ file to give metadata
+information is (assuming the document name is +foo+) :
+
+* +FOO_SOURCES+, mandatory, defines the source files for the document.
+
+* +FOO_RESOURCES+, optional, may contain a space-separated list of paths
+  to one or more directories containing so-called resources (like CSS or
+  images). By default, empty.
+
+There are also additional hooks (see xref:hooks[] for general information
+on hooks), that a document may set to define extra actions to be done at
+various steps:
+
+* +FOO_POST_RSYNC_HOOKS+ to run additional commands after the sources
+  have been copied by Buildroot. This can for example be used to
+  generate part of the manual with information extracted from the
+  tree. As an example, Buildroot uses this hook to generate the tables
+  in the appendices.
+
+* +FOO_CHECK_DEPENDENCIES_HOOKS+ to run additional tests on required
+  components to generate the document. In AsciiDoc, it is possible to
+  call filters, that is, programs that will parse an AsciiDoc block and
+  render it appropriately (e.g. http://ditaa.sourceforge.net/[ditaa] or
+  https://pythonhosted.org/aafigure/[aafigure]).
+
+* +FOO_CHECK_DEPENDENCIES_<FMT>_HOOKS+, to run additional tests for
+  the specified format +<FMT>+ (see the list of rendered formats, above).
+
+Here is a complete example that uses all variables and all hooks:
+
+----
+01: ################################################################################
+02: #
+03: # foo-document
+04: #
+05: ################################################################################
+06:
+07: FOO_SOURCES = $(sort $(wildcard $(pkgdir)/*))
+08: FOO_RESOURCES = $(sort $(wildcard $(pkgdir)/ressources))
+09:
+10: define FOO_GEN_EXTRA_DOC
+11:     /path/to/generate-script --outdir=$(@D)
+12: endef
+13: FOO_POST_RSYNC_HOOKS += FOO_GEN_EXTRA_DOC
+14:
+15: define FOO_CHECK_MY_PROG
+16:     if ! which my-prog >/dev/null 2>&1; then \
+17:         echo "You need my-prog to generate the foo document"; \
+18:         exit 1; \
+19:     fi
+20: endef
+21: FOO_CHECK_DEPENDENCIES_HOOKS += FOO_CHECK_MY_PROG
+22:
+23: define FOO_CHECK_MY_OTHER_PROG
+24:     if ! which my-other-prog >/dev/null 2>&1; then \
+25:         echo "You need my-other-prog to generate the foo document as PDF"; \
+26:         exit 1; \
+27:     fi
+28: endef
+29: FOO_CHECK_DEPENDENCIES_PDF_HOOKS += FOO_CHECK_MY_OTHER_PROG
+30:
+31: $(eval $(call asciidoc-document))
+----

docs/manual/adding-packages.txt

@@ -27,6 +27,8 @@ include::adding-packages-virtual.txt[]
 
 include::adding-packages-kconfig.txt[]
 
+include::adding-packages-asciidoc.txt[]
+
 include::adding-packages-hooks.txt[]
 
 include::adding-packages-gettext.txt[]