3 files changed, 10 insertions, 0 deletions
diff --git a/lib/gras_impl/interruptible_thread.hpp b/lib/gras_impl/interruptible_thread.hpp
index 1e99111..e7025bf 100644
--- a/lib/gras_impl/interruptible_thread.hpp
+++ b/lib/gras_impl/interruptible_thread.hpp
@@ -91,6 +91,7 @@ namespace gnuradio
                 {
                     while (_wait_msg) _cond.wait(lock);
                     _wait_msg = true;
+                    if (not _callable) break;
                     _callable();
                     _wait_ack = false;
                     _notify(lock);
diff --git a/lib/gras_impl/messages.hpp b/lib/gras_impl/messages.hpp
index d5bfc8b..e1a3565 100644
--- a/lib/gras_impl/messages.hpp
+++ b/lib/gras_impl/messages.hpp
@@ -52,6 +52,12 @@ struct BufferReturnMessage
     SBuffer buffer;
 };
 
+struct BufferHintMessage
+{
+    size_t history_bytes;
+    size_t reserve_bytes;
+    WeakToken token;
+};
 
 } //namespace gnuradio
 
diff --git a/lib/gras_impl/token.hpp b/lib/gras_impl/token.hpp
index 4923f74..d5b438a 100644
--- a/lib/gras_impl/token.hpp
+++ b/lib/gras_impl/token.hpp
@@ -18,10 +18,13 @@
 #define INCLUDED_LIBGRAS_IMPL_TOKEN_HPP
 
 #include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
 
 namespace gnuradio
 {
 
+typedef boost::weak_ptr<int> WeakToken;
+
 struct Token : boost::shared_ptr<int>
 {
     static Token make(void)