doc: rebuild with meson whenever a file changes

Add proper support for calling sphinx whenever a file in the doc
directory changes. This is accomplished by using a wrapper script
for sphinx, which runs sphinx but also emits a gcc-format dependency
file listing all the doc files. This is used by ninja so that any
change to the doc files triggers a rebuild of the docs.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Aaron Conole <aconole@redhat.com>
Acked-by: Luca Boccassi <bluca@debian.org>

MAINTAINERS

@@ -128,6 +128,7 @@ F: meson.build
 F: lib/librte_eal/freebsd/BSDmakefile.meson
 F: meson_options.txt
 F: config/rte_config.h
+F: buildtools/call-sphinx-build.py
 F: buildtools/gen-pmdinfo-cfile.sh
 F: buildtools/map_to_def.py
 F: buildtools/symlink-drivers-solibs.sh

buildtools/call-sphinx-build.py

@@ -0,0 +1,31 @@
+#! /usr/bin/env python3
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2019 Intel Corporation
+#
+
+import sys
+import os
+from os.path import join
+from subprocess import run, PIPE
+from distutils.version import StrictVersion
+
+(sphinx, src, dst) = sys.argv[1:]  # assign parameters to variables
+
+# for sphinx version >= 1.7 add parallelism using "-j auto"
+ver = run([sphinx, '--version'], stdout=PIPE).stdout.decode().split()[-1]
+sphinx_cmd = [sphinx]
+if StrictVersion(ver) >= StrictVersion('1.7'):
+    sphinx_cmd += ['-j', 'auto']
+
+# find all the files sphinx will process so we can write them as dependencies
+srcfiles = []
+for root, dirs, files in os.walk(src):
+    srcfiles.extend([join(root, f) for f in files])
+
+# run sphinx, putting the html output in a "html" directory
+process = run(sphinx_cmd + ['-b', 'html', src, join(dst, 'html')], check=True)
+print(str(process.args) + ' Done OK')
+
+# create a gcc format .d file giving all the dependencies of this doc build
+with open(join(dst, '.html.d'), 'w') as d:
+    d.write('html: ' + ' '.join(srcfiles) + '\n')

buildtools/meson.build

@@ -10,10 +10,12 @@ check_experimental_syms = find_program('check-experimental-syms.sh')
 # set up map-to-def script using python, either built-in or external
 python3 = import('python').find_installation(required: false)
 if python3.found()
-	map_to_def_cmd = [python3, files('map_to_def.py')]
+	py3 = [python3]
 else
-	map_to_def_cmd = ['meson', 'runpython', files('map_to_def.py')]
+	py3 = ['meson', 'runpython']
 endif
+map_to_def_cmd = py3 + files('map_to_def.py')
+sphinx_wrapper = py3 + files('call-sphinx-build.py')
 
 # stable ABI always starts with "DPDK_"
 is_experimental_cmd = [find_program('grep', 'findstr'), '^DPDK_']

doc/guides/meson.build

@@ -7,24 +7,18 @@ if not sphinx.found()
 	subdir_done()
 endif
 
-htmldir = join_paths('share', 'doc', 'dpdk')
+htmldir = join_paths(get_option('datadir'), 'doc', 'dpdk')
 html_guides = custom_target('html_guides',
-	input: meson.current_source_dir(),
-	output: 'guides',
-	command: [sphinx, '-b', 'html',
-		'-d', meson.current_build_dir() + '/.doctrees',
-		'@INPUT@', meson.current_build_dir() + '/guides'],
+	input: files('index.rst'),
+	output: 'html',
+	command: [sphinx_wrapper, sphinx, meson.current_source_dir(), meson.current_build_dir()],
+	depfile: '.html.d',
 	build_by_default: get_option('enable_docs'),
 	install: get_option('enable_docs'),
 	install_dir: htmldir)
 
+install_data(files('custom.css'),
+			install_dir: join_paths(htmldir,'_static', 'css'))
+
 doc_targets += html_guides
 doc_target_names += 'HTML_Guides'
-
-# sphinx leaves a .buildinfo in the target directory, which we don't
-# want to install. Note that sh -c has to be used, otherwise the
-# env var does not get expanded if calling rm/install directly.
-meson.add_install_script('sh', '-c',
-	'rm -f $MESON_INSTALL_DESTDIR_PREFIX/share/doc/dpdk/guides/.buildinfo')
-meson.add_install_script('sh', '-c',
-	'install -D -m0644 $MESON_SOURCE_ROOT/doc/guides/custom.css $MESON_INSTALL_DESTDIR_PREFIX/share/doc/dpdk/guides/_static/css/custom.css')