buildroot/docs/manual/adding-packages-asciidoc.txt
Yann E. MORIN a88718a952 docs/manual: document the br2-external NAME
Update the manual with the new external.desc mandatory file.

Take the opportunity to add a section listing all mandatory files,
Config.in, external.mk and the new external.desc, instead of just
hinting about them in the external package recipes section.

Change the examples to use the NAME-suffixed variable instead of the
raw BR2_EXTERNAL variable.

Change all references to BR2_EXTERNAL elsewhere in the manual to now
use the 'br2-external tree' terminology.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Romain Naour <romain.naour@openwide.fr>
Cc: Julien CORJON <corjon.j@ecagroup.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2016-10-16 13:01:02 +02:00

125 lines
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// -*- 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 a
xref:outside-br-custom[br2-external tree]. 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.
* +FOO_DEPENDENCIES+, optional, the list of packages (most probably,
host-packages) that must be built before building this document.
If a hook of your document needs to access the _Kconfig_ structure,
you may add +prepare-kconfig+ to the list of dependencies.
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))
----