Document plug-in interface

[babeltrace.git] / include / babeltrace / plugin / plugin.h

diff --git a/include/babeltrace/plugin/plugin.h b/include/babeltrace/plugin/plugin.h
index 1c3c36d0ac734b5644735b16ccd90b9074a4fed6..1080e2bb2f2b1e93ac2bce1877f348897dc1bf7d 100644 (file)
--- a/include/babeltrace/plugin/plugin.h
+++ b/include/babeltrace/plugin/plugin.h
@@ -27,19 +27,102 @@
  * SOFTWARE.
  */
 
+#include <errno.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+/**
+ * Plug-in type.
+ */
+enum bt_plugin_type {
+       BT_PLUGIN_TYPE_UNKNOWN =        -1,
+
+       /* A source plug-in is a notification generator. */
+       BT_PLUGIN_TYPE_SOURCE =         0,
+
+       /* A sink plug-in handles incoming notifications. */
+       BT_PLUGIN_TYPE_SINK =           1,
+
+       /* A filter plug-in implements both Source and Sink interfaces. */
+       BT_PLUGIN_TYPE_FILTER =         2,
+};
+
+/**
+ * Status code. Errors are always negative.
+ */
+enum bt_plugin_status {
+       /* -12 for compatibility with -ENOMEM */
+       BT_PLUGIN_STATUS_NOMEM =        -12,
+
+       /* -22 for compatibility with -EINVAL */
+       BT_PLUGIN_STATUS_INVAL =        -22,
+
+       BT_PLUGIN_STATUS_UNSUPPORTED =  -2,
+
+       BT_PLUGIN_STATUS_ERROR =        -1,
+
+       BT_PLUGIN_STATUS_OK =           0,
+}
+
+/**
+ * Get plug-in instance name
+ *
+ * @param plugin       Plug-in instance of which to get the name
+ * @returns            Returns a pointer to the plug-in's name
+ */
+extern const char *bt_plugin_get_name(struct bt_plugin *plugin);
+
+/**
+ * Set plug-in instance name
+ *
+ * @param plugin       Plug-in instance of which to set the name
+ * @param name         New plug-in name (will be copied)
+ * @returns            One of #bt_plugin_status values
+ */
+extern enum bt_plugin_status bt_plugin_set_name(
+               struct bt_plugin *plugin, const char *name);
+
+/**
+ * Get plug-in instance type
+ *
+ * @param plugin       Plug-in instance of which to get the type
+ * @returns            One of #bt_plugin_type values
+ */
+extern enum bt_plugin_type bt_plugin_get_type(struct bt_plugin *plugin);
 
-int bt_plugin_set_error_stream(struct bt_plugin *plugin, FILE *error_stream);
+/**
+ * Set a plug-in instance's error stream
+ *
+ * @param plugin       Plug-in instance
+ * @param error_stream Error stream
+ * @returns            One of #bt_plugin_status values
+ */
+extern enum bt_plugin_status bt_plugin_set_error_stream(
+               struct bt_plugin *plugin, FILE *error_stream);
 
-/* Refcounting */
-void bt_plugin_get(struct bt_plugin *plugin);
-void bt_plugin_put(struct bt_plugin *plugin);
+/**
+ * Increments the reference count of \p plugin.
+ *
+ * @param plugin       Plug-in of which to increment the reference count
+ *
+ * @see bt_plugin_put()
+ */
+extern void bt_plugin_get(struct bt_plugin *plugin);
+
+/**
+ * Decrements the reference count of \p plugin, destroying it when this
+ * count reaches 0.
+ *
+ * @param plugin       Plug-in of which to decrement the reference count
+ *
+ * @see bt_plugin_get()
+ */
+extern void bt_plugin_put(struct bt_plugin *plugin);
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* BABELTRACE_PLUGIN_SYSTEM_H */
+#endif /* BABELTRACE_PLUGIN_H */