[gtkmm-documentation] Meson build: Add allow-network-access option

[Kjell Ahlstedt <kjellahl src gnome org>]

commit c135dad6d67c8b7a03c9eb1e1263b0b8de2ce6ff
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Wed Feb 23 15:14:28 2022 +0100

    Meson build: Add allow-network-access option
    
    If false, xmllint and xsltproc are not allowed to fetch files
    over the network, and gtkmm-documentation requires the docbook5-xml
    and docbook-xsl packages (Ubuntu names, can have other names in
    other distros).

 docs/tutorial/meson.build              |  7 ++++-
 meson.build                            | 19 ++++++------
 meson_options.txt                      |  2 ++
 tools/meson_aux/tutorial-custom-cmd.py | 54 ++++++++++++++++++++++------------
 4 files changed, 54 insertions(+), 28 deletions(-)
---
diff --git a/docs/tutorial/meson.build b/docs/tutorial/meson.build
index 73dab49..eefdb06 100644
--- a/docs/tutorial/meson.build
+++ b/docs/tutorial/meson.build
@@ -11,12 +11,14 @@ xsltproc = find_program('xsltproc', required: true)
 xmllint = find_program('xmllint', required: false)
 can_parse_and_validate = xmllint.found()
 validate = get_option('validation') ? 'true' : 'false'
+allow_network_access = get_option('allow-network-access') ? 'true' : 'false'
 
 # Check if xmllint can be used.
 if xmllint.found()
   can_parse_and_validate = run_command(
     python3, tutorial_custom_cmd, 'xmllint',
     validate,
+    allow_network_access,
     meson.current_source_dir() / 'can_use_xmllint.xml',
     meson.current_build_dir() / 'can_use_xmllint.stamp',
     check: false,
@@ -36,7 +38,7 @@ can_build_translations = find_program('msgfmt', required: false).found() and \
 build_translations_by_default = get_option('build-translations')
 
 dblatex = find_program('dblatex', required: false)
-can_build_pdf = dblatex.found() or (xsltproc.found() and \
+can_build_pdf = xsltproc.found() and (dblatex.found() or \
                 find_program('fop', required: false).found())
 build_pdf_by_default = get_option('build-pdf')
 
@@ -182,6 +184,7 @@ custom_target('html_index.html',
   output: 'html',
   command: [
     python3, tutorial_custom_cmd, 'html',
+    allow_network_access,
     '@INPUT@',
     '@OUTPUT@',    
   ],
@@ -203,6 +206,7 @@ if can_parse_and_validate
     command: [
       python3, tutorial_custom_cmd, 'xmllint',
       validate,
+      allow_network_access,
       '@INPUT@',
       '@OUTPUT@'
     ],
@@ -219,6 +223,7 @@ if can_build_pdf
     command: [
       python3, tutorial_custom_cmd,
       dblatex.found() ? 'dblatex' : 'fop',
+      allow_network_access,
       '@INPUT@',
       meson.current_source_dir() / 'C' / 'figures',
       '@OUTPUT@'
diff --git a/meson.build b/meson.build
index 17ef025..4e48f9e 100644
--- a/meson.build
+++ b/meson.build
@@ -121,7 +121,7 @@ endif
 build_pdf = build_pdf_by_default and can_build_pdf
 explain_pdf = ''
 if build_pdf_by_default and not build_pdf
-  explain_pdf = ' (requires dblatex or (xsltproc and fop))'
+  explain_pdf = ' (requires xsltproc and (dblatex or fop))'
 endif
 
 summary = [
@@ -129,15 +129,16 @@ summary = [
   '------',
   meson.project_name() + ' ' + meson.project_version(),
   '',
-  '    Build examples: @0@@1@'.format(build_examples_by_default, explain_ex),
-  ' Compiler warnings: @0@'.format(warning_level),
-  '    XML validation: @0@@1@'.format(validate, explain_val),
-  'Build translations: @0@@1@'.format(build_translations, explain_trans),
-  '         Build PDF: @0@@1@'.format(build_pdf, explain_pdf),
+  '      Build examples: @0@@1@'.format(build_examples_by_default, explain_ex),
+  '   Compiler warnings: @0@'.format(warning_level),
+  '      XML validation: @0@@1@'.format(validate, explain_val),
+  'Allow network access: @0@'.format(get_option('allow-network-access')),
+  '  Build translations: @0@@1@'.format(build_translations, explain_trans),
+  '           Build PDF: @0@@1@'.format(build_pdf, explain_pdf),
   'Directories:',
-  '            prefix: @0@'.format(install_prefix),
-  '           datadir: @0@'.format(install_prefix / install_datadir),
-  '       tutorialdir: @0@'.format(install_prefix / tutorialdir),
+  '              prefix: @0@'.format(install_prefix),
+  '             datadir: @0@'.format(install_prefix / install_datadir),
+  '         tutorialdir: @0@'.format(install_prefix / tutorialdir),
   '------'
 ]
 
diff --git a/meson_options.txt b/meson_options.txt
index 95b8d50..8bedd06 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -6,6 +6,8 @@ option('build-examples', type: 'boolean', value: false,
   description: 'Build all example programs')
 option('validation', type: 'boolean', value: true,
   description: 'Validate the untranslated XML file')
+option('allow-network-access', type: 'boolean', value: true,
+  description: 'Allow xmllint and xsltproc to fetch files over the network')
 option('build-translations', type: 'boolean', value: true,
   description: 'Build translated tutorials (built during installation)')
 option('build-pdf', type: 'boolean', value: false,
diff --git a/tools/meson_aux/tutorial-custom-cmd.py b/tools/meson_aux/tutorial-custom-cmd.py
index a97c4c9..d775adc 100755
--- a/tools/meson_aux/tutorial-custom-cmd.py
+++ b/tools/meson_aux/tutorial-custom-cmd.py
@@ -51,11 +51,12 @@ def insert_ex_code():
 
 # Called from custom_target()
 def html():
-  #      argv[2]          argv[3]
-  # <input_xml_file> <output_html_dir>
+  #      argv[2]               argv[3]           argv[4]
+  # <allow_network_access> <input_xml_file> <output_html_dir>
 
-  input_xml_file = sys.argv[2]
-  output_html_dir = sys.argv[3]
+  allow_network_access = sys.argv[2] == 'true'
+  input_xml_file = sys.argv[3]
+  output_html_dir = sys.argv[4]
 
   # Set the use.id.as.filename param so that we don't use the chapter / section
   # number as the filename, otherwise the url will change every time anything is
@@ -86,6 +87,10 @@ def html():
   ] + xslt_params + [
     '-o', output_html_dir + '/',
     '--xinclude',
+  ]
+  if not allow_network_access:
+    cmd += ['--nonet']
+  cmd += [
     xslt_stylesheet,
     input_xml_file,
   ]
@@ -101,12 +106,13 @@ def html():
 # Called from custom_target()
 def xmllint():
 
-  #  argv[2]       argv[3]          argv[4]
-  # <validate> <input_xml_file> <stamp_file_path>
+  #  argv[2]          argv[3]              argv[4]          argv[5]
+  # <validate> <allow_network_access> <input_xml_file> <stamp_file_path>
 
   validate = sys.argv[2]
-  input_xml_file = sys.argv[3]
-  stamp_file_path = sys.argv[4]
+  allow_network_access = sys.argv[3] == 'true'
+  input_xml_file = sys.argv[4]
+  stamp_file_path = sys.argv[5]
 
   relax_ng_schema = 'http://docbook.org/xml/5.0/rng/docbook.rng'
   # schematron_schema = 'http://docbook.org/xml/5.0/sch/docbook.sch'
@@ -128,6 +134,8 @@ def xmllint():
       '--relaxng', relax_ng_schema,
       #'--schematron', schematron_schema,
     ]
+  if not allow_network_access:
+    cmd += ['--nonet']
   cmd += [input_xml_file]
   result = subprocess.run(cmd)
   if result.returncode:
@@ -180,13 +188,14 @@ def translate_xml():
 # xsltproc+xmlroff (version 0.6.3) does not seem to work acceptably.
 # Called from custom_target()
 def dblatex():
-  #      argv[2]        argv[3]        argv[4]
-  # <input_xml_file> <figures_dir> <output_pdf_file>
+  #        argv[2]              argv[3]        argv[4]         argv[5]
+  # <allow_network_access> <input_xml_file> <figures_dir> <output_pdf_file>
   # Create a PDF file, using dblatex.
 
-  input_xml_file = sys.argv[2]
-  figures_dir = sys.argv[3]
-  output_pdf_file = sys.argv[4]
+  allow_network_access = sys.argv[2] == 'true'
+  input_xml_file = sys.argv[3]
+  figures_dir = sys.argv[4]
+  output_pdf_file = sys.argv[5]
 
   # For a list of available parameters, see http://dblatex.sourceforge.net/doc/manual/
   dblatex_params = [
@@ -203,19 +212,24 @@ def dblatex():
     '-I', figures_dir_parent,
     '-o', output_pdf_file,
     '--pdf',
+  ]
+  if not allow_network_access:
+    cmd += ['-x', '--nonet'] # --nonet is passed to xsltproc
+  cmd += [
     input_xml_file,
   ]
   return subprocess.run(cmd).returncode
 
 # Called from custom_target()
 def fop():
-  #      argv[2]        argv[3]        argv[4]
-  # <input_xml_file> <figures_dir> <output_pdf_file>
+  #         argv[2]            argv[3]         argv[4]         argv[5]
+  # <allow_network_access> <input_xml_file> <figures_dir> <output_pdf_file>
   # Create a PDF file, using fop.
 
-  input_xml_file = sys.argv[2]
-  figures_dir = sys.argv[3]
-  output_pdf_file = sys.argv[4]
+  allow_network_access = sys.argv[2] == 'true'
+  input_xml_file = sys.argv[3]
+  figures_dir = sys.argv[4]
+  output_pdf_file = sys.argv[5]
 
   fo_file = os.path.splitext(output_pdf_file)[0] + '.fo'
 
@@ -244,6 +258,10 @@ def fop():
   ] + xslt_params + [
     '-o', fo_file,
     '--xinclude',
+  ]
+  if not allow_network_access:
+    cmd += ['--nonet']
+  cmd += [
     xslt_stylesheet,
     input_xml_file,
   ]