gio-module-cache: Add class for Gio modules

The new class uses gio-querymodules tool on postinst and postrm.
This regenerates the module cache which is useful to avoid loading
modules that are not needed at runtime: If a Gio module is not
listed in the cache file it will always get loaded.

* Add a postinst-intercept 'gio-module-cache': it runs
  gio-querymodules using qemuwrapper. This is required because the tool
  actually loads the modules to generate the cache.
* Add a gio-module-cache class that adds postinstall and postrm
  scripts. In the sysroot population case use the new intercept.
* Inherit the new class in glib-2.0, glib-networking and gconf.

Fixes [YOCTO #9241].

(From OE-Core rev: 168cf5502a2dda78348cc9679e37bed0c69c0208)

Signed-off-by: Jussi Kukkonen <jussi.kukkonen@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/gio-module-cache.bbclass

@@ -0,0 +1,37 @@
+DEPENDS += "qemu-native"
+inherit qemu
+
+GIO_MODULE_PACKAGES ??= "${PN}"
+
+gio_module_cache_common() {
+if [ "x$D" != "x" ]; then
+    $INTERCEPT_DIR/postinst_intercept update_gio_module_cache ${PKG} \
+            mlprefix=${MLPREFIX} \
+            binprefix=${MLPREFIX} \
+            libdir=${libdir} \
+            base_libdir=${base_libdir} \
+            bindir=${bindir}
+else
+    ${libexecdir}/${MLPREFIX}gio-querymodules ${libdir}/gio/modules/
+fi
+}
+
+python populate_packages_append () {
+    packages = d.getVar('GIO_MODULE_PACKAGES', True).split()
+
+    for pkg in packages:
+        bb.note("adding gio-module-cache postinst and postrm scripts to %s" % pkg)
+
+        postinst = d.getVar('pkg_postinst_%s' % pkg, True)
+        if not postinst:
+            postinst = '#!/bin/sh\n'
+        postinst += d.getVar('gio_module_cache_common', True)
+        d.setVar('pkg_postinst_%s' % pkg, postinst)
+
+        postrm = d.getVar('pkg_postrm_%s' % pkg, True)
+        if not postrm:
+            postrm = '#!/bin/sh\n'
+        postrm += d.getVar('gio_module_cache_common', True)
+        d.setVar('pkg_postrm_%s' % pkg, postrm)
+}
+