diff -r 000000000000 -r 6474c204b198 config/createprecomplete.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/config/createprecomplete.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,75 @@
+# Any copyright is dedicated to the Public Domain.
+# http://creativecommons.org/publicdomain/zero/1.0/
+
+# Creates the precomplete file containing the remove and rmdir application
+# update instructions which is used to remove files and directories that are no
+# longer present in a complete update. The current working directory is used for
+# the location to enumerate and to create the precomplete file.
+# For symlinks, remove instructions are always generated.
+
+import sys
+import os
+
+def get_build_entries(root_path):
+    """ Iterates through the root_path, creating a list for each file and
+        directory. Excludes any file paths ending with channel-prefs.js.
+        To support Tor Browser updates, excludes:
+          TorBrowser/Data/Browser/profiles.ini
+          TorBrowser/Data/Browser/profile.default/bookmarks.html
+          TorBrowser/Data/Tor/torrc
+    """
+    rel_file_path_set = set()
+    rel_dir_path_set = set()
+    for root, dirs, files in os.walk(root_path):
+        for file_name in files:
+            parent_dir_rel_path = root[len(root_path)+1:]
+            rel_path_file = os.path.join(parent_dir_rel_path, file_name)
+            rel_path_file = rel_path_file.replace("\\", "/")
+            if not (rel_path_file.endswith("channel-prefs.js") or
+                    rel_path_file.endswith("update-settings.ini") or
+                    rel_path_file == "TorBrowser/Data/Browser/profiles.ini" or
+                    rel_path_file == "TorBrowser/Data/Browser/profile.default/bookmarks.html" or
+                    rel_path_file == "TorBrowser/Data/Tor/torrc" or
+                    rel_path_file.find("distribution/") != -1):
+                rel_file_path_set.add(rel_path_file)
+
+        for dir_name in dirs:
+            parent_dir_rel_path = root[len(root_path)+1:]
+            rel_path_dir = os.path.join(parent_dir_rel_path, dir_name)
+            rel_path_dir = rel_path_dir.replace("\\", "/")+"/"
+            if rel_path_dir.find("distribution/") == -1:
+                if (os.path.islink(rel_path_dir[:-1])):
+                    rel_file_path_set.add(rel_path_dir[:-1])
+                else:
+                    rel_dir_path_set.add(rel_path_dir)
+
+    rel_file_path_list = list(rel_file_path_set)
+    rel_file_path_list.sort(reverse=True)
+    rel_dir_path_list = list(rel_dir_path_set)
+    rel_dir_path_list.sort(reverse=True)
+
+    return rel_file_path_list, rel_dir_path_list
+
+def generate_precomplete(root_path):
+    """ Creates the precomplete file containing the remove and rmdir
+        application update instructions. The given directory is used
+        for the location to enumerate and to create the precomplete file.
+    """
+    # If inside a Mac bundle use the root of the bundle for the path.
+    if os.path.basename(root_path) == "MacOS":
+        root_path = os.path.abspath(os.path.join(root_path, '../../'))
+
+    rel_file_path_list, rel_dir_path_list = get_build_entries(root_path)
+    precomplete_file_path = os.path.join(root_path,"precomplete")
+    # open in binary mode to prevent OS specific line endings.
+    precomplete_file = open(precomplete_file_path, "wb")
+    for rel_file_path in rel_file_path_list:
+        precomplete_file.writelines("remove \""+rel_file_path+"\"\n")
+
+    for rel_dir_path in rel_dir_path_list:
+        precomplete_file.writelines("rmdir \""+rel_dir_path+"\"\n")
+
+    precomplete_file.close()
+
+if __name__ == "__main__":
+    generate_precomplete(os.getcwd())