# 
# 
# patch "database.cc"
#  from [40233e632e2045e6f9327d9c0dfe51e93491236c]
#    to [f22f2ec7d8c1741d20388581203084a34a290794]
# 
# patch "roster_delta.cc"
#  from [e55ee69820c741d7ef44e8f2bfb094a2898bdebb]
#    to [4d06fa6a95df2ff254ce9572a57bc0b0d1bb7e52]
# 
# patch "roster_delta.hh"
#  from [c469955ebc623dd5986883c7751a1010e530a963]
#    to [85506c111153554e2184a41cae920e4198890bfd]
# 
============================================================
--- database.cc	40233e632e2045e6f9327d9c0dfe51e93491236c
+++ database.cc	f22f2ec7d8c1741d20388581203084a34a290794
@@ -1412,7 +1412,7 @@ database::get_markings(revision_id const
         {
           roster_delta del;
           get_roster_delta(id.inner()(), *i, del);
-          bool found = get_markings_from_roster_delta(del, nid, markings);
+          bool found = try_get_markings_from_roster_delta(del, nid, markings);
           if (found)
             return;
         }
@@ -1431,7 +1431,7 @@ database::get_markings(revision_id const
         {
           roster_delta del;
           get_roster_delta(target_rev, *p, del);
-          bool found = get_markings_from_roster_delta(del, nid, markings);
+          bool found = try_get_markings_from_roster_delta(del, nid, markings);
           if (found)
             return;
         }
@@ -1477,7 +1477,7 @@ database::get_file_content(revision_id c
         {
           roster_delta del;
           get_roster_delta(id.inner()(), *i, del);
-          bool found = get_content_from_roster_delta(del, nid, content);
+          bool found = try_get_content_from_roster_delta(del, nid, content);
           if (found)
             return;
         }
@@ -1496,7 +1496,7 @@ database::get_file_content(revision_id c
         {
           roster_delta del;
           get_roster_delta(target_rev, *p, del);
-          bool found = get_content_from_roster_delta(del, nid, content);
+          bool found = try_get_content_from_roster_delta(del, nid, content);
           if (found)
             return;
         }
============================================================
--- roster_delta.cc	e55ee69820c741d7ef44e8f2bfb094a2898bdebb
+++ roster_delta.cc	4d06fa6a95df2ff254ce9572a57bc0b0d1bb7e52
@@ -476,8 +476,8 @@ static
 }
 
 static
-void get_roster_delta(roster_delta const & del,
-                      roster_delta_t & d)
+void read_roster_delta(roster_delta const & del,
+                       roster_delta_t & d)
 {
   basic_io::input_source src(del.inner()(), "roster_delta");
   basic_io::tokenizer tok(src);
@@ -494,19 +494,19 @@ apply_roster_delta(roster_delta const & 
   MM(markings);
 
   roster_delta_t d;
-  get_roster_delta(del, d);
+  read_roster_delta(del, d);
   d.apply(roster, markings);
 }
 
 // Extract the marking for one node from the roster delta, or return false
 // if they are not contained in that delta
 bool
-get_markings_from_roster_delta(roster_delta const & del,
-                               node_id const & nid,
-                               marking_t & markings)
+try_get_markings_from_roster_delta(roster_delta const & del,
+                                   node_id const & nid,
+                                   marking_t & markings)
 {
   roster_delta_t d;
-  get_roster_delta(del, d);
+  read_roster_delta(del, d);
 
   std::map<node_id, marking_t>::iterator i = d.markings_changed.find(nid);
   if (i != d.markings_changed.end())
@@ -520,15 +520,19 @@ get_markings_from_roster_delta(roster_de
     }
 }
 
-// Extract the content hash for one node from the roster delta. Return false
-// if this delta doesn't contain information about this node.
+// Extract the content hash for one node from the roster delta -- if it is
+// available.  If we know what the file_id was, we return true and set
+// 'content' appropriately.  If we can prove that the file did not exist in
+// this revision, we return true and set 'content' to a null id.  If we
+// cannot determine anything about the file contents, then we return false
+// -- in this case content is left undefined.
 bool
-get_content_from_roster_delta(roster_delta const & del,
+try_get_content_from_roster_delta(roster_delta const & del,
                               node_id const & nid,
                               file_id & content)
 {
   roster_delta_t d;
-  get_roster_delta(del, d);
+  read_roster_delta(del, d);
   
   roster_delta_t::deltas_applied_t::const_iterator i = d.deltas_applied.find(nid);
   if (i != d.deltas_applied.end())
============================================================
--- roster_delta.hh	c469955ebc623dd5986883c7751a1010e530a963
+++ roster_delta.hh	85506c111153554e2184a41cae920e4198890bfd
@@ -26,14 +26,15 @@ bool
                    roster_t & roster, marking_map & markings);
                    
 bool
-get_markings_from_roster_delta(roster_delta const & del,
-                               node_id const & nid,
-                               marking_t & markings);
+try_get_markings_from_roster_delta(roster_delta const & del,
+                                   node_id const & nid,
+                                   marking_t & markings);
 
+// See the comment on this function's body for a description of its api.
 bool
-get_content_from_roster_delta(roster_delta const & del,
-                              node_id const & nid,
-                              file_id & content);
+try_get_content_from_roster_delta(roster_delta const & del,
+                                  node_id const & nid,
+                                  file_id & content);
   
 #ifdef BUILD_UNIT_TESTS