[gnome-software] Use a symbol cache when calling gs_plugin_get_symbol()

[Richard Hughes <rhughes src gnome org>]

commit 65f722c0ffd3124b0175a5ab9946f82a6229c553
Author: Richard Hughes <richard hughsie com>
Date:   Sat Nov 26 09:34:04 2016 +0000

    Use a symbol cache when calling gs_plugin_get_symbol()
    
    During startup we're spending 50ms of CPU time just resolving symbols.

 src/gs-plugin.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)
---
diff --git a/src/gs-plugin.c b/src/gs-plugin.c
index 4b11826..cacfbec 100644
--- a/src/gs-plugin.c
+++ b/src/gs-plugin.c
@@ -66,6 +66,7 @@ typedef struct
        SoupSession             *soup_session;
        GsAppList               *global_cache;
        GPtrArray               *rules[GS_PLUGIN_RULE_LAST];
+       GHashTable              *vfuncs;                /* string:pointer */
        gboolean                 enabled;
        gchar                   *locale;                /* allow-none */
        gchar                   *language;              /* allow-none */
@@ -203,6 +204,7 @@ gs_plugin_finalize (GObject *object)
        if (priv->global_cache != NULL)
                g_object_unref (priv->global_cache);
        g_hash_table_unref (priv->cache);
+       g_hash_table_unref (priv->vfuncs);
        g_mutex_clear (&priv->cache_mutex);
        g_mutex_clear (&priv->timer_mutex);
        if (priv->module != NULL)
@@ -345,8 +347,14 @@ gs_plugin_get_symbol (GsPlugin *plugin, const gchar *function_name)
        if (!priv->enabled)
                return NULL;
 
-       /* look up the symbol */
+       /* look up the symbol from the cache */
+       if (g_hash_table_lookup_extended (priv->vfuncs, function_name, NULL, &func))
+               return func;
+
+       /* look up the symbol using the elf headers */
        g_module_symbol (priv->module, function_name, &func);
+       g_hash_table_insert (priv->vfuncs, g_strdup (function_name), func);
+
        return func;
 }
 
@@ -1585,6 +1593,8 @@ gs_plugin_init (GsPlugin *plugin)
                                             (GEqualFunc) as_utils_unique_id_equal,
                                             g_free,
                                             (GDestroyNotify) g_object_unref);
+       priv->vfuncs = g_hash_table_new_full (g_str_hash, g_str_equal,
+                                             g_free, NULL);
        g_mutex_init (&priv->cache_mutex);
        g_mutex_init (&priv->timer_mutex);
        g_rw_lock_init (&priv->rwlock);