1 files changed, 38 insertions, 1 deletions
diff --git a/src/core/mainloop/mainloop_pubsub.h b/src/core/mainloop/mainloop_pubsub.h
index 365a3dd565..3698fd8d03 100644
--- a/src/core/mainloop/mainloop_pubsub.h
+++ b/src/core/mainloop/mainloop_pubsub.h
@@ -1,17 +1,54 @@
 /* Copyright (c) 2001, Matej Pfajfar.
  * Copyright (c) 2001-2004, Roger Dingledine.
  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, The Tor Project, Inc. */
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * @file mainloop_pubsub.h
+ * @brief Header for mainloop_pubsub.c
+ **/
+
 #ifndef TOR_MAINLOOP_PUBSUB_H
 #define TOR_MAINLOOP_PUBSUB_H
 
 struct pubsub_builder_t;
 
+/**
+ * Describe when and how messages are delivered on message channel.
+ *
+ * Every message channel must be associated with one of these strategies.
+ **/
 typedef enum {
+   /**
+    * Never deliver messages automatically.
+    *
+    * If a message channel uses this strategy, then no matter now many
+    * messages are published on it, they are not delivered until something
+    * manually calls dispatch_flush() for that channel
+    **/
    DELIV_NEVER=0,
+   /**
+    * Deliver messages promptly, via the event loop.
+    *
+    * If a message channel uses this strategy, then publishing a messages
+    * that channel activates an event that causes messages to be handled
+    * later in the mainloop.  The messages will be processed at some point
+    * very soon, delaying only for pending IO events and the like.
+    *
+    * Generally this is the best choice for a delivery strategy, since
+    * it avoids stack explosion.
+    **/
    DELIV_PROMPT,
+   /**
+    * Deliver messages immediately, skipping the event loop.
+    *
+    * Every event on this channel is flushed immediately after it is queued,
+    * using the stack.
+    *
+    * This delivery type should be used with caution, since it can cause
+    * unexpected call chains, resource starvation, and the like.
+    **/
    DELIV_IMMEDIATE,
 } deliv_strategy_t;