meson: add update-orc-dist target

Add target to update backup orc -dist.[ch] files.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1408>

gst/bayer/meson.build

@@ -14,6 +14,7 @@ if have_orcc
     input : orcsrc + '.orc',
     output : orcsrc + '.c',
     command : orcc_args + ['--implementation', '-o', '@OUTPUT@', '@INPUT@'])
+  orc_targets += {'name': orcsrc, 'orc-source': files(orcsrc + '.orc'), 'header': orc_h, 'source': orc_c}
 else
   orc_h = configure_file(input : orcsrc + '-dist.h',
     output : orcsrc + '.h',

gst/fieldanalysis/meson.build

@@ -12,6 +12,7 @@ if have_orcc
     input : orcsrc + '.orc',
     output : orcsrc + '.c',
     command : orcc_args + ['--implementation', '-o', '@OUTPUT@', '@INPUT@'])
+  orc_targets += {'name': orcsrc, 'orc-source': files(orcsrc + '.orc'), 'header': orc_h, 'source': orc_c}
 else
   orc_h = configure_file(input : orcsrc + '-dist.h',
     output : orcsrc + '.h',

gst/gaudieffects/meson.build

@@ -19,6 +19,7 @@ if have_orcc
     input : orcsrc + '.orc',
     output : orcsrc + '.c',
     command : orcc_args + ['--implementation', '-o', '@OUTPUT@', '@INPUT@'])
+  orc_targets += {'name': orcsrc, 'orc-source': files(orcsrc + '.orc'), 'header': orc_h, 'source': orc_c}
 else
   orc_h = configure_file(input : orcsrc + '-dist.h',
     output : orcsrc + '.h',

meson.build

@@ -373,6 +373,7 @@ have_objcpp = add_languages('objcpp', native: false, required: false)
 
 have_orcc = false
 orcc_args = []
+orc_targets = []
 # Used by various libraries/elements that use Orc code
 orc_dep = dependency('orc-0.4', version : orc_req, required : get_option('orc'),
     fallback : ['orc', 'orc_dep'])
@@ -446,6 +447,29 @@ subdir('data')
 subdir('tools')
 subdir('pkgconfig')
 
+if have_orcc
+  update_orc_dist_files = find_program('scripts/update-orc-dist-files.py')
+
+  orc_update_targets = []
+  foreach t : orc_targets
+    orc_name = t.get('name')
+    orc_file = t.get('orc-source')
+    header = t.get('header')
+    source = t.get('source')
+    # alias_target() only works with build targets, so can't use run_target() here
+    orc_update_targets += [
+      custom_target('update-orc-@0@'.format(orc_name),
+        input: [header, source],
+        command: [update_orc_dist_files, orc_file, header, source],
+        output: ['@0@-dist.c'.format(orc_name)]) # not entirely true
+    ]
+  endforeach
+
+  if meson.version().version_compare('>= 0.52')
+    update_orc_dist_target = alias_target('update-orc-dist', orc_update_targets)
+  endif
+endif
+
 # xgettext is optional (on Windows for instance)
 if find_program('xgettext', required : get_option('nls')).found()
   cdata.set('ENABLE_NLS', 1)

scripts/update-orc-dist-files.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+#
+# update-orc-dist-files.py ORC-FILE GENERATED-HEADER GENERATED-SOURCE
+#
+# Copies generated orc .c and .h files into source dir as -dist.[ch] backups,
+# based on location of passed .orc file.
+#
+# Copyright (C) 2020 Tim-Philipp Müller <tim centricular com>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Library General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Library General Public License for more details.
+#
+# You should have received a copy of the GNU Library General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+# Boston, MA 02110-1301, USA.
+
+import shutil
+import subprocess
+import sys
+
+assert(len(sys.argv) == 4)
+
+orc_file = sys.argv[1]
+gen_header = sys.argv[2]
+gen_source = sys.argv[3]
+
+# split off .orc suffix
+assert(orc_file.endswith('.orc'))
+orc_src_base = sys.argv[1][:-4]
+
+# figure out names of disted backup files
+dist_h = orc_src_base + "-dist.h"
+dist_c = orc_src_base + "-dist.c"
+
+# copy generated files from build dir into source dir
+shutil.copyfile(gen_header, dist_h)
+shutil.copyfile(gen_source, dist_c)
+
+# run gst-indent on the .c files (twice, because gnu indent)
+subprocess.run(['gst-indent', dist_c])
+subprocess.run(['gst-indent', dist_c])