propagate_tags director for python

2 files changed, 32 insertions, 13 deletions

diff --git a/include/gras/block.hpp b/include/gras/block.hpp
index bddc0f4..70c570c 100644
--- a/include/gras/block.hpp
+++ b/include/gras/block.hpp
@@ -163,14 +163,18 @@ struct GRAS_API Block : Element
     void erase_input_tags(const size_t which_input);
 
     /*!
-     * Overload me to implement tag propagation logic:
+     * Overload me to implement custom tag propagation logic:
      *
      * Propagate tags will be given an iterator for all input tags
      * whose offset counts is less than the number of items consumed.
-     * It is the job of the propagate_tags overload to
+     * It is the job of the propagate_tags overloaded function to
      * propagate tags to the downstream and interpolate the offset.
-     * By default, the propagate_tags implementation is a NOP.
-     * Also, the user may simple propagate tags from within work.
+     *
+     * By default, the propagate_tags implementation is to:
+     * broadcast each consumed input tags to all output ports
+     * using the local input offset as the local output offset.
+     *
+     * Also, the user may simply propagate tags from within work.
      */
     virtual void propagate_tags(const size_t which_input, const TagIter &iter);
 
diff --git a/python/gras/GRAS_Block.i b/python/gras/GRAS_Block.i
index f068b25..2aa1166 100644
--- a/python/gras/GRAS_Block.i
+++ b/python/gras/GRAS_Block.i
@@ -69,7 +69,6 @@ struct PyGILPhondler
 %include <std_vector.i>
 %template () std::vector<size_t>;
 %template () std::vector<void *>;
-%template () std::vector<gras::Tag>;
 
 ////////////////////////////////////////////////////////////////////////
 // Pull in the implementation goodies
@@ -168,8 +167,11 @@ struct BlockPython : Block
 
     void propagate_tags(const size_t which_input, const TagIter &iter)
     {
-        //TODO implement _Py_ version of this
+        PyGILPhondler phil;
+        return this->_Py_propagate_tags(which_input, iter);
     }
+
+    virtual void _Py_propagate_tags(const size_t which_input, const TagIter &iter) = 0;
 };
 
 }
@@ -217,6 +219,14 @@ class Tag(object):
         self.value = value
         self.srcid = srcid
 
+def YieldTagIter(iter):
+    for t in iter: yield Tag(
+        offset=t.offset,
+        key=PMC2Py(t.key),
+        value=PMC2Py(t.value),
+        srcid=PMC2Py(t.srcid),
+    )
+
 class Block(BlockPython):
     def __init__(self, name='Block', in_sig=None, out_sig=None):
         BlockPython.__init__(self, name)
@@ -290,12 +300,17 @@ class Block(BlockPython):
         BlockPython.post_output_tag(self, which_output, t)
 
     def get_input_tags(self, which_input):
-        for t in BlockPython.get_input_tags(self, which_input):
-            yield Tag(
-                offset=t.offset,
-                key=PMC2Py(t.key),
-                value=PMC2Py(t.value),
-                srcid=PMC2Py(t.srcid),
-            )
+        return YieldTagIter(BlockPython.get_input_tags(self, which_input))
+
+    def _Py_propagate_tags(self, which_input, iter):
+        try: return self.propagate_tags(which_input, iter)
+        except: traceback.print_exc(); raise
+
+    def propagate_tags(self, i, iter):
+        for o in self.__out_indexes:
+            for t in YieldTagIter(iter):
+                t.offset -= self.get_consumed(i)
+                t.offset += self.get_produced(o)
+                self.post_output_tag(o, t)
 
 %}