open-uri: add temporary keyfile deserialization

This adds support for deserializing URI handlers from `.desktop`
overrides in the user data directory, with the format:

```
[URI Handler example.com]
Scheme=https;
Host=example.com;*.example.com;
Port=443;
Path=/resource/*
```

src/open-uri.c

@@ -520,6 +520,113 @@ uri_handler_free (UriHandler *handler)
   g_free (handler);
 }
 
+/*
+ * Temporary deserialization
+ */
+static UriHandler *
+uri_handler_deserialize (GKeyFile   *keyfile,
+                         const char *group)
+{
+  UriHandler *ret = NULL;
+  g_auto (GStrv) ports = NULL;
+
+  g_assert (keyfile != NULL);
+  g_assert (group != NULL && *group != '\0');
+
+  ret = g_new0 (UriHandler, 1);
+  ret->schemes = g_key_file_get_string_list (keyfile, group, "Scheme", NULL, NULL);
+  ret->hosts = g_key_file_get_string_list (keyfile, group, "Host", NULL, NULL);
+  ret->paths = g_key_file_get_string_list (keyfile, group, "Path", NULL, NULL);
+
+  ports = g_key_file_get_string_list (keyfile, group, "Port", NULL, NULL);
+  if (ports != NULL)
+    {
+      unsigned int n_ports = g_strv_length (ports);
+
+      ret->ports = g_array_new (TRUE, TRUE, sizeof (uint16_t));
+      for (unsigned int i = 0; i < n_ports; i++)
+        {
+          guint64 port = g_ascii_strtoull (ports[i], NULL, 10);
+
+          if (port > 0 && port < UINT16_MAX)
+            g_array_append_vals (ret->ports, (uint16_t *)&port, 1);
+        }
+    }
+
+  return ret;
+}
+
+static GHashTable *
+uri_handler_load_keyfiles (void)
+{
+  GHashTable *ret = NULL;
+  g_autoptr (GFile) search_path = NULL;
+  g_autoptr (GFileEnumerator) search_dir = NULL;
+
+  ret = g_hash_table_new_full (g_str_hash,
+                               g_str_equal,
+                               g_free,
+                               (GDestroyNotify)g_ptr_array_unref);
+
+  search_path = g_file_new_build_filename (g_get_user_data_dir (),
+                                           "applications",
+                                           NULL);
+  search_dir = g_file_enumerate_children (search_path,
+                                          G_FILE_ATTRIBUTE_STANDARD_NAME,
+                                          G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
+                                          NULL,
+                                          NULL);
+
+  while (TRUE)
+    {
+      GFile *file;
+      g_autoptr (GPtrArray) handlers = NULL;
+      g_autoptr (GKeyFile) keyfile = NULL;
+      g_auto (GStrv) groups = NULL;
+      g_autofree char *filepath = NULL;
+
+      if (!g_file_enumerator_iterate (search_dir, NULL, &file, NULL, NULL))
+        break;
+
+      if (file == NULL)
+        break;
+
+      filepath = g_file_get_path (file);
+      keyfile = g_key_file_new ();
+      if (!g_key_file_load_from_file (keyfile, filepath, G_KEY_FILE_NONE, NULL))
+        continue;
+
+      handlers = g_ptr_array_new_with_free_func ((GDestroyNotify)uri_handler_free);
+      groups = g_key_file_get_groups (keyfile, NULL);
+      for (size_t i = 0; groups[i] != NULL; i++)
+        {
+          UriHandler *handler = NULL;
+
+          if (!g_str_has_prefix (groups[i], "URI Handler"))
+            continue;
+
+          handler = uri_handler_deserialize (keyfile, groups[i]);
+          g_ptr_array_add (handlers, handler);
+        }
+
+      if (handlers->len > 0)
+        {
+          g_autofree char *basename = NULL;
+          g_autofree char *app_id = NULL;
+
+          basename = g_file_get_basename (file);
+          app_id = g_strndup (basename, strlen (basename) - strlen (".desktop"));
+
+          g_debug ("Found %u handlers for %s", handlers->len, app_id);
+          g_hash_table_replace (ret,
+                                g_steal_pointer (&app_id),
+                                g_steal_pointer (&handlers));
+        }
+    }
+
+  return ret;
+}
+
 static gboolean
 uri_handler_match (UriHandler *handler,
                    GUri       *uri)
@@ -654,7 +761,7 @@ find_patterned_choices (XdpAppInfo *app,
       return;
     }
 
-  candidates = g_hash_table_new (g_str_hash, g_str_equal);
+  candidates = uri_handler_load_keyfiles ();
   builder = g_strv_builder_new ();
 
   g_hash_table_iter_init (&iter, candidates);