[Libosinfo] [libosinfo 3/6] loader: Introduce OSINFO_ERROR

[Christophe Fergeau]

Since glib commit 2.31.10~16 [1], g_set_error() will issue a warning if
it's passed a NULL domain. libosinfo is doing this in a few places (try
for example 'osinfo-query os winxp'). This commit adds a generic OSINFO_ERROR
domain which will be used instead of NULL. It's a bit inconsistent with
OSINFO_MEDIA_ERROR and OSINFO_TREE_ERROR in that they both start with
"osinfo-*" while OSINFO_ERROR uses "libosinfo". However, since
OsinfoLoader already makes use of that quark, changing that would
arguably be an (very small) ABI break.

[1] https://gitlab.gnome.org/GNOME/glib/commit/6d9f874330
---
 osinfo/libosinfo.syms  |  5 +++++
 osinfo/osinfo_loader.c | 24 +++++++++++++++++++++---
 osinfo/osinfo_loader.h |  8 ++++++++
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/osinfo/libosinfo.syms b/osinfo/libosinfo.syms
index 6bd08a10..db9b8b20 100644
--- a/osinfo/libosinfo.syms
+++ b/osinfo/libosinfo.syms
@@ -529,6 +529,11 @@ LIBOSINFO_0.2.13 {
 	osinfo_media_get_eject_after_install;
 } LIBOSINFO_0.2.12;
 
+LIBOSINFO_1.3.0 {
+    global:
+	osinfo_error_quark;
+} LIBOSINFO_0.2.13;
+
 /* Symbols in next release...
 
   LIBOSINFO_0.0.2 {
diff --git a/osinfo/osinfo_loader.c b/osinfo/osinfo_loader.c
index 3accb29e..d1bf61d9 100644
--- a/osinfo/osinfo_loader.c
+++ b/osinfo/osinfo_loader.c
@@ -144,8 +144,26 @@ OsinfoLoader *osinfo_loader_new(void)
     return g_object_new(OSINFO_TYPE_LOADER, NULL);
 }
 
-#define OSINFO_LOADER_SET_ERROR(err, msg)                               \
-    g_set_error_literal((err), g_quark_from_static_string("libosinfo"), 0, (msg));
+/**
+ * osinfo_error_quark:
+ *
+ * Gets a #GQuark representing the string "libosinfo"
+ *
+ * Returns: the #GQuark representing the string.
+ **/
+GQuark
+osinfo_error_quark(void)
+{
+    static GQuark quark = 0;
+
+    if (!quark)
+        quark = g_quark_from_static_string("libosinfo");
+
+    return quark;
+}
+
+#define OSINFO_LOADER_SET_ERROR(err, msg)                                        \
+    g_set_error_literal((err), OSINFO_ERROR, 0, (msg));
 
 static gboolean error_is_set(GError **error)
 {
@@ -191,7 +209,7 @@ osinfo_loader_nodeset(const char *xpath,
     if (obj == NULL)
         return 0;
     if (obj->type != XPATH_NODESET) {
-        g_set_error(err, g_quark_from_static_string("libosinfo"), 0,
+        g_set_error(err, OSINFO_ERROR, 0,
                     _("Expected a nodeset in XPath query %s"), xpath);
         xmlXPathFreeObject(obj);
         return -1;
diff --git a/osinfo/osinfo_loader.h b/osinfo/osinfo_loader.h
index 41bfb146..76beb7ce 100644
--- a/osinfo/osinfo_loader.h
+++ b/osinfo/osinfo_loader.h
@@ -66,6 +66,14 @@ struct _OsinfoLoaderClass
 
 GType osinfo_loader_get_type(void);
 
+/**
+ * OSINFO_ERROR:
+ *
+ * Error domain for generic libosinfo errors
+ */
+#define OSINFO_ERROR osinfo_error_quark()
+GQuark osinfo_error_quark(void);
+
 OsinfoLoader *osinfo_loader_new(void);
 
 OsinfoDb *osinfo_loader_get_db(OsinfoLoader *loader);
-- 
2.19.0