From 6c4af0398d260316dd2dd2358a02000cbf84ceba Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Mon, 30 Jan 2017 17:42:00 +0100
Subject: [PATCH] allow external code to use DLL pointers of envelopes, under
 very particular circumstances

---
 src/include/gnunet_mq_lib.h | 36 +++++++++++++++++++++++++++++
 src/util/mq.c               | 46 +++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/src/include/gnunet_mq_lib.h b/src/include/gnunet_mq_lib.h
index 108ba5d54..b527b58e8 100644
--- a/src/include/gnunet_mq_lib.h
+++ b/src/include/gnunet_mq_lib.h
@@ -268,6 +268,42 @@ typedef void
                            enum GNUNET_MQ_Error error);
 
 
+/**
+ * Insert @a env into the envelope DLL starting at @a env_head
+ * Note that @a env must not be in any MQ while this function
+ * is used with DLLs defined outside of the MQ module.  This
+ * is just in case some application needs to also manage a
+ * FIFO of envelopes independent of MQ itself and wants to
+ * re-use the pointers internal to @a env.  Use with caution.
+ *
+ * @param[in|out] env_head of envelope DLL
+ * @param[in|out] env_tail tail of envelope DLL
+ * @param[in|out] env element to insert at the tail
+ */
+void
+GNUNET_MQ_dll_insert_tail (struct GNUNET_MQ_Envelope **env_head,
+                           struct GNUNET_MQ_Envelope **env_tail,
+                           struct GNUNET_MQ_Envelope *env);
+
+
+/**
+ * Remove @a env from the envelope DLL starting at @a env_head.
+ * Note that @a env must not be in any MQ while this function
+ * is used with DLLs defined outside of the MQ module. This
+ * is just in case some application needs to also manage a
+ * FIFO of envelopes independent of MQ itself and wants to
+ * re-use the pointers internal to @a env.  Use with caution.
+ *
+ * @param[in|out] env_head of envelope DLL
+ * @param[in|out] env_tail tail of envelope DLL
+ * @param[in|out] env element to remove from the DLL
+ */
+void
+GNUNET_MQ_dll_remove (struct GNUNET_MQ_Envelope **env_head,
+                      struct GNUNET_MQ_Envelope **env_tail,
+                      struct GNUNET_MQ_Envelope *env);
+
+
 /**
  * Message handler for a specific message type.
  */
diff --git a/src/util/mq.c b/src/util/mq.c
index d12f69e5f..bd7ad7c47 100644
--- a/src/util/mq.c
+++ b/src/util/mq.c
@@ -1140,4 +1140,50 @@ GNUNET_MQ_destroy_notify_cancel (struct GNUNET_MQ_DestroyNotificationHandle *dnh
 }
 
 
+/**
+ * Insert @a env into the envelope DLL starting at @a env_head
+ * Note that @a env must not be in any MQ while this function
+ * is used with DLLs defined outside of the MQ module.  This
+ * is just in case some application needs to also manage a
+ * FIFO of envelopes independent of MQ itself and wants to
+ * re-use the pointers internal to @a env.  Use with caution.
+ *
+ * @param[in|out] env_head of envelope DLL
+ * @param[in|out] env_tail tail of envelope DLL
+ * @param[in|out] env element to insert at the tail
+ */
+void
+GNUNET_MQ_dll_insert_tail (struct GNUNET_MQ_Envelope **env_head,
+                           struct GNUNET_MQ_Envelope **env_tail,
+                           struct GNUNET_MQ_Envelope *env)
+{
+  GNUNET_CONTAINER_DLL_insert_tail (*env_head,
+                                    *env_tail,
+                                    env);
+}
+
+
+/**
+ * Remove @a env from the envelope DLL starting at @a env_head.
+ * Note that @a env must not be in any MQ while this function
+ * is used with DLLs defined outside of the MQ module. This
+ * is just in case some application needs to also manage a
+ * FIFO of envelopes independent of MQ itself and wants to
+ * re-use the pointers internal to @a env.  Use with caution.
+ *
+ * @param[in|out] env_head of envelope DLL
+ * @param[in|out] env_tail tail of envelope DLL
+ * @param[in|out] env element to remove from the DLL
+ */
+void
+GNUNET_MQ_dll_remove (struct GNUNET_MQ_Envelope **env_head,
+                      struct GNUNET_MQ_Envelope **env_tail,
+                      struct GNUNET_MQ_Envelope *env)
+{
+  GNUNET_CONTAINER_DLL_remove (*env_head,
+                               *env_tail,
+                               env);
+}
+
+
 /* end of mq.c */
-- 
2.25.1