Meson: Build fam module

gio-querymodules-wrapper.py is copied from glib-networking. This python
wrapper script is needed because meson.build cannot check for DESTDIR
env variable itself, unlike Makefile.am. It is used to update
giomodule.cache file when installing GIO modules like fam.

gio/Makefile.am

@@ -820,6 +820,7 @@ gio-2.0.lib: libgio-2.0.la gio.def
 	$(AM_V_GEN) lib.exe -machine:@LIB_EXE_MACHINE_FLAG@ -name:libgio-2.0-$(LT_CURRENT_MINUS_AGE).dll -def:$(builddir)/gio.def -out:$@
 
 bin_PROGRAMS = gio-querymodules glib-compile-schemas glib-compile-resources gsettings
+EXTRA_DIST += gio-querymodules-wrapper.py
 
 glib_compile_resources_LDADD = libgio-2.0.la 		\
 	$(top_builddir)/gobject/libgobject-2.0.la	\

gio/fam/gfamfilemonitor.map

@@ -0,0 +1,8 @@
+{
+global:
+  g_io_module_load;
+  g_io_module_unload;
+  g_io_module_query;
+local:
+  *;
+};

gio/fam/meson.build

@@ -0,0 +1,36 @@
+# FIXME: We should use subdir_done() instead of if blocks, but it's broken in
+# meson 0.46.1. See https://github.com/mesonbuild/meson/issues/3700.
+if get_option('fam')
+  fam_dep = cc.find_library('fam')
+  fam_c_args = ['-DG_DISABLE_DEPRECATED'] + gio_c_args
+  if cc.has_function('FAMNoExists', dependencies : fam_dep)
+    fam_c_args += '-DHAVE_FAM_NO_EXISTS=1'
+  endif
+
+  deps = [
+    fam_dep,
+    libglib_dep,
+    libgobject_dep,
+    libgio_dep,
+  ]
+
+  symbol_map = join_paths(meson.current_source_dir(), 'gfamfilemonitor.map')
+  fam_ldflags = cc.get_supported_link_arguments([
+    '-Wl,--version-script,' + symbol_map,
+    '-Wl,-no-undefined',
+  ])
+
+  module = shared_module('giofam', 'gfamfilemonitor.c',
+    include_directories : [gmoduleinc],
+    dependencies : deps,
+    c_args : fam_c_args,
+    link_args : fam_ldflags,
+    link_depends : symbol_map,
+    install_dir : glib_giomodulesdir,
+    install : true,
+  )
+
+  if not meson.is_cross_build()
+    meson.add_install_script('../gio-querymodules-wrapper.py', gio_querymodules.full_path(), glib_giomodulesdir)
+  endif
+endif

gio/gio-querymodules-wrapper.py

@@ -0,0 +1,9 @@
+#!/usr/bin/env python3
+
+import os
+import subprocess
+import sys
+
+if not os.environ.get('DESTDIR'):
+  print('GIO module cache creation...')
+  subprocess.call([sys.argv[1], sys.argv[2]])

gio/meson.build

@@ -759,11 +759,6 @@ if host_system == 'windows'
   internal_deps += [ giowin32_lib ]
 endif
 
-# FIXME: FAM support
-#if HAVE_FAM
-#  subdir('fam')
-#endif
-
 if have_bash
   install_data([
     'completion/gapplication',
@@ -900,7 +895,7 @@ executable('gresource', 'gresource-tool.c',
   link_args : noseh_link_args,
   dependencies : [libelf, libgio_dep, libgobject_dep, libgmodule_dep, libglib_dep])
 
-executable('gio-querymodules', 'gio-querymodules.c', 'giomodule-priv.c',
+gio_querymodules = executable('gio-querymodules', 'gio-querymodules.c', 'giomodule-priv.c',
   install : true,
   c_args : gio_c_args,
   # intl.lib is not compatible with SAFESEH
@@ -958,6 +953,8 @@ if enable_systemtap
     install : true)
 endif
 
+subdir('fam')
+
 if host_system != 'windows'
   subdir('tests')
 endif

meson_options.txt

@@ -73,3 +73,8 @@ option('force_posix_threads',
        type : 'boolean',
        value : false,
        description : 'Also use posix threads in case the platform defaults to another implementation (on Windows for example)')
+
+option('fam',
+       type : 'boolean',
+       value : false,
+       description : 'Use fam for file system monitoring')