support adding buffers to other buffers non-destructively

1 files changed, 15 insertions, 0 deletions

diff --git a/evbuffer-internal.h b/evbuffer-internal.h
index 6bb3e2c1..75d026d3 100644
--- a/evbuffer-internal.h
+++ b/evbuffer-internal.h
@@ -183,6 +183,11 @@ struct evbuffer_chain {
 	/** a chain that should be freed, but can't be freed until it is
 	 * un-pinned. */
 #define EVBUFFER_DANGLING	0x0040
+	/** a chain that is a referenced copy of another chain */
+#define EVBUFFER_MULTICAST	0x0080
+
+	/** number of multicast references to this chain */
+	int refcnt;
 
 	/** Usually points to the read-write memory belonging to this
 	 * buffer allocated as part of the evbuffer_chain allocation.
@@ -240,6 +245,16 @@ struct evbuffer_file_segment {
 	ev_off_t length;
 };
 
+/** Information about the multicast parent of a chain.  Lives at the
+ * end of an evbuffer_chain with the EVBUFFER_MULTICAST flag set.  */
+struct evbuffer_multicast_parent {
+#ifndef _EVENT_DISABLE_THREAD_SUPPORT
+	void *lock; /**< lock prevent concurrent access to the parent */
+#endif
+	/** multicast parent for this chain */
+	struct evbuffer_chain *parent;
+};
+
 #define EVBUFFER_CHAIN_SIZE sizeof(struct evbuffer_chain)
 /** Return a pointer to extra data allocated along with an evbuffer. */
 #define EVBUFFER_CHAIN_EXTRA(t, c) (t *)((struct evbuffer_chain *)(c) + 1)