Course Blocks App MA-1556

openedx/core/lib/block_cache/__init__.py

@@ -51,7 +51,10 @@ Registry. Transformers are registered using the platform's
 PluginManager (e.g., Stevedore). This is currently done by updating
 setup.py.  Only registered transformers are called during the Collect
 Phase.  And only registered transformers can be used during the
-Transform phase.
+Transform phase.  Exceptions to this rule are any nested transformers
+that are contained within higher-order transformers - as long as the
+higher-order transformers are registered and appropriately call the
+contained transformers within them.
 
 Note: A partial subset (as an ordered list) of the registered
 transformers can be requested during the Transform phase, allowing

openedx/core/lib/block_cache/block_cache.py

@@ -36,6 +36,12 @@ def get_blocks(cache, modulestore, usage_info, root_block_usage_key, transformer
             transformers whose transform methods are to be called.
             This list should be a subset of the list of registered
             transformers in the Transformer Registry.
+
+    Returns:
+        BlockStructureBlockData - A transformed block structure,
+            starting at root_block_usage_key, that has undergone the
+            transform methods in the given transformers with the
+            given usage_info.
     """
 
     # Verify that all requested transformers are registered in the

openedx/core/lib/block_cache/block_structure.py

@@ -118,6 +118,16 @@ class BlockStructure(object):
         """
         return usage_key in self._block_relations
 
+    def get_block_keys(self):
+        """
+        Returns the block keys in the block structure.
+
+        Returns:
+            iterator(UsageKey) - An iterator of the usage
+            keys of all the blocks in the block structure.
+        """
+        return self._block_relations.iterkeys()
+
     #--- Block structure traversal methods ---#
 
     def topological_traversal(
@@ -198,13 +208,6 @@ class BlockStructure(object):
         # Replace this structure's relations with the newly pruned one.
         self._block_relations = pruned_block_relations
 
-    def _get_block_keys(self):
-        """
-        Returns an iterator of all the block keys in the block
-        structure.
-        """
-        return self._block_relations.iterkeys()
-
     def _add_relation(self, parent_key, child_key):
         """
         Adds a parent to child relationship in this block structure.