[Spice-devel] [PATCH v1 1/2] gst: add helper for runtime check on gst plugin version

[Victor Toso]

From: Victor Toso <me at victortoso.com>

This patch factor out the runtime check for pulsesrc plugin version in
order to be used in the follow up patch by channel-display-gst.c

This code can be shared between spice-gstaudio.c and
channel-display-gst.c.

Signed-off-by: Victor Toso <victortoso at redhat.com>
---
 src/spice-gstaudio.c     | 89 ++++++++++++++++++++++++++--------------
 src/spice-session-priv.h |  3 ++
 2 files changed, 62 insertions(+), 30 deletions(-)

diff --git a/src/spice-gstaudio.c b/src/spice-gstaudio.c
index 5f4a2fe..4bab17f 100644
--- a/src/spice-gstaudio.c
+++ b/src/spice-gstaudio.c
@@ -26,6 +26,7 @@
 #include "spice-common.h"
 #include "spice-session.h"
 #include "spice-util.h"
+#include "spice-session-priv.h"
 
 struct stream {
     GstElement              *pipe;
@@ -549,45 +550,73 @@ static gboolean connect_channel(SpiceAudio *audio, SpiceChannel *channel)
     return FALSE;
 }
 
+/* Runtime check if a given @plugin_name is >= @major. at minor.@micro version in the system.
+ * Set @err and return FALSE on unexected errors */
+G_GNUC_INTERNAL gboolean
+spice_check_gst_plugin_version(const gchar *plugin_name,
+                               guint major, guint minor, guint micro,
+                               GError **err)
+{
+    GstPluginFeature *plugin_feature;
+    GstPlugin *plugin;
+    guint nmatch, plugin_major, plugin_minor, plugin_micro;
+
+    if (!gst_init_check(NULL, NULL, err)) {
+        return FALSE;
+    }
+
+    plugin_feature = gst_registry_lookup_feature(gst_registry_get(), plugin_name);
+    if (!plugin_feature) {
+        return FALSE;
+    }
+
+    plugin = gst_plugin_feature_get_plugin(plugin_feature);
+    nmatch = sscanf(gst_plugin_get_version(plugin), "%u.%u.%u",
+                    &plugin_major, &plugin_minor, &plugin_micro);
+
+    spice_debug("Requiring %s version %u.%u.%u, system has %s",
+                plugin_name, major, minor, micro, gst_plugin_get_version(plugin));
+    gst_object_unref(plugin);
+    gst_object_unref(plugin_feature);
+
+    if (nmatch != 3) {
+        *err = g_error_new(G_IO_ERROR, G_IO_ERROR_FAILED,
+                           "bad versioning scheme for plugin %s", plugin_name);
+        return FALSE;
+    }
+
+    if (plugin_major != major) {
+        return plugin_major > major;
+    }
+
+    if (plugin_minor != minor) {
+        return plugin_minor > minor;
+    }
+
+    return plugin_micro >= micro;
+}
+
 SpiceGstaudio *spice_gstaudio_new(SpiceSession *session, GMainContext *context,
                                   const char *name)
 {
     GError *err = NULL;
 
-    if (gst_init_check(NULL, NULL, &err)) {
-        GstPluginFeature *pulsesrc;
-
-        pulsesrc = gst_registry_lookup_feature(gst_registry_get(), "pulsesrc");
-        if (pulsesrc) {
-            unsigned major, minor, micro;
-            GstPlugin *plugin = gst_plugin_feature_get_plugin(pulsesrc);
-
-            if (sscanf(gst_plugin_get_version(plugin), "%u.%u.%u",
-                       &major, &minor, &micro) != 3) {
-                g_warn_if_reached();
-                gst_object_unref(plugin);
-                gst_object_unref(pulsesrc);
-                return NULL;
-            }
-
-            if (major < 1 ||
-                (major == 1 && minor < 14) ||
-                (major == 1 && minor == 14 && micro < 5)) {
-                g_warning("Bad pulsesrc version %s, lowering its rank",
-                          gst_plugin_get_version(plugin));
-                gst_plugin_feature_set_rank(pulsesrc, GST_RANK_NONE);
-            }
-
-            gst_object_unref(plugin);
-            gst_object_unref(pulsesrc);
+    if (!spice_check_gst_plugin_version("pulsesrc", 1, 14, 5, &err)) {
+        if (err != NULL) {
+            goto err_out;
         }
+        g_warning("Bad pulsesrc version, set plugin's rank to NONE");
 
-        return g_object_new(SPICE_TYPE_GSTAUDIO,
-                            "session", session,
-                            "main-context", context,
-                            NULL);
+        GstPluginFeature *pulsesrc = gst_registry_lookup_feature(gst_registry_get(), "pulsesrc");
+        gst_plugin_feature_set_rank(pulsesrc, GST_RANK_NONE);
+        gst_object_unref(pulsesrc);
     }
 
+    return g_object_new(SPICE_TYPE_GSTAUDIO,
+                        "session", session,
+                        "main-context", context,
+                        NULL);
+err_out:
     g_warning("Disabling GStreamer audio support: %s", err->message);
     g_clear_error(&err);
     return NULL;
diff --git a/src/spice-session-priv.h b/src/spice-session-priv.h
index 6ece7e0..fa14826 100644
--- a/src/spice-session-priv.h
+++ b/src/spice-session-priv.h
@@ -98,6 +98,9 @@ guint spice_session_get_n_display_channels(SpiceSession *session);
 gboolean spice_session_set_migration_session(SpiceSession *session, SpiceSession *mig_session);
 SpiceAudio *spice_audio_get(SpiceSession *session, GMainContext *context);
 const gchar* spice_audio_data_mode_to_string(gint mode);
+gboolean spice_check_gst_plugin_version(const gchar *plugin_name,
+                               guint major, guint minor, guint micro,
+                               GError **err);
 G_END_DECLS
 
 #endif /* __SPICE_CLIENT_SESSION_PRIV_H__ */
-- 
2.20.1