1 files changed, 39 insertions, 13 deletions
diff --git a/tools/buildgen/plugins/expand_filegroups.py b/tools/buildgen/plugins/expand_filegroups.py
index 156bdc4417..c40143ef95 100755
--- a/tools/buildgen/plugins/expand_filegroups.py
+++ b/tools/buildgen/plugins/expand_filegroups.py
@@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -42,6 +42,9 @@ def excluded(filename, exclude_res):
   return False
 
 
+FILEGROUP_LISTS = ['src', 'headers', 'public_headers']
+
+
 def mako_plugin(dictionary):
   """The exported plugin code for expand_filegroups.
 
@@ -54,21 +57,44 @@ def mako_plugin(dictionary):
   filegroups_list = dictionary.get('filegroups')
   filegroups = {}
 
-  for fg in filegroups_list:
-    filegroups[fg['name']] = fg
+  todo = filegroups_list[:]
+  skips = 0
+
+  while todo:
+    assert skips != len(todo), "infinite loop in filegroup uses clauses"
+    # take the first element of the todo list
+    cur = todo[0]
+    todo = todo[1:]
+    # check all uses filegroups are present (if no, skip and come back later)
+    skip = False
+    for uses in cur.get('uses', []):
+      if uses not in filegroups:
+        skip = True
+    if skip:
+      skips += 1
+      todo.append(cur)
+    else:
+      skips = 0
+      for uses in cur.get('uses', []):
+        for lst in FILEGROUP_LISTS:
+          vals = cur.get(lst, [])
+          vals.extend(filegroups[uses].get(lst, []))
+          cur[lst] = vals
+      filegroups[cur['name']] = cur
+
+  # the above expansion can introduce duplicate filenames: contract them here
+  for fg in filegroups.itervalues():
+    for lst in FILEGROUP_LISTS:
+      fg[lst] = sorted(list(set(fg.get(lst, []))))
 
   for lib in libs:
     for fg_name in lib.get('filegroups', []):
       fg = filegroups[fg_name]
 
-      src = lib.get('src', [])
-      src.extend(fg.get('src', []))
-      lib['src'] = src
-
-      headers = lib.get('headers', [])
-      headers.extend(fg.get('headers', []))
-      lib['headers'] = headers
+      for lst in FILEGROUP_LISTS:
+        vals = lib.get(lst, [])
+        vals.extend(fg.get(lst, []))
+        lib[lst] = vals
 
-      public_headers = lib.get('public_headers', [])
-      public_headers.extend(fg.get('public_headers', []))
-      lib['public_headers'] = public_headers
+    for lst in FILEGROUP_LISTS:
+      lib[lst] = sorted(list(set(lib.get(lst, []))))