From f2de8985e8e7e406e02f1a95db025da22c29fe7c Mon Sep 17 00:00:00 2001
From: Vladimir Diaz <vladimir.v.diaz@gmail.com>
Date: Thu, 21 Dec 2017 15:54:06 -0500
Subject: [PATCH] Add option to exclude custom field when matching targetinfo

Signed-off-by: Vladimir Diaz <vladimir.v.diaz@gmail.com>
---
 tuf/client/updater.py | 43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/tuf/client/updater.py b/tuf/client/updater.py
index 22daa0e7..59b46025 100755
--- a/tuf/client/updater.py
+++ b/tuf/client/updater.py
@@ -118,6 +118,7 @@
 import shutil
 import time
 import fnmatch
+import copy
 
 import tuf
 import tuf.download
@@ -223,7 +224,7 @@ def __init__(self, map_file):
 
 
 
-  def get_valid_targetinfo(self, target_filename):
+  def get_valid_targetinfo(self, target_filename, match_custom_field=True):
     """
     <Purpose>
       Get valid targetinfo, if any, for the given 'target_filename'.  The map
@@ -236,6 +237,11 @@ def get_valid_targetinfo(self, target_filename):
       target_filename:
         The relative path of the target file to update.
 
+      match_custom_field:
+        Boolean that indicates whether the optional custom field in targetinfo
+        should match across the targetinfo provided by the threshold of
+        repositories.
+
     <Exceptions>
       tuf.exceptions.FormatError, if the argument is improperly formatted.
 
@@ -284,7 +290,8 @@ def get_valid_targetinfo(self, target_filename):
       else:
         # Do the repositories in the mapping provide a threshold of matching
         # targetinfo?
-        valid_targetinfo = self._matching_targetinfo(target_filename, mapping)
+        valid_targetinfo = self._matching_targetinfo(target_filename,
+            mapping, match_custom_field)
 
         if valid_targetinfo:
           return valid_targetinfo
@@ -350,7 +357,8 @@ def _verify_metadata_directories(self, repositories_directory):
 
 
 
-  def _matching_targetinfo(self, target_filename, mapping):
+  def _matching_targetinfo(
+      self, target_filename, mapping, match_custom_field=True):
     valid_targetinfo = {}
 
     # Retrieve the targetinfo from each repository using the underlying
@@ -369,19 +377,19 @@ def _matching_targetinfo(self, target_filename, mapping):
       valid_targetinfo[updater] = targetinfo
 
       matching_targetinfo = {}
-      matches = 0
       logger.debug('Verifying that a threshold of targetinfo are equal...')
 
-      for valid_updater, valid_targetinfo in six.iteritems(valid_targetinfo):
-        if targetinfo != valid_targetinfo:
+      for valid_updater, compared_targetinfo in six.iteritems(valid_targetinfo):
+
+        if not self._targetinfo_match(
+            targetinfo, compared_targetinfo, match_custom_field):
           continue
 
         else:
 
-          matching_targetinfo[updater] = targetinfo
-          matches = matches + 1
+          matching_targetinfo[valid_updater] = targetinfo
 
-          if not matches >= mapping['threshold']:
+          if not len(matching_targetinfo) >= mapping['threshold']:
             continue
 
           else:
@@ -399,6 +407,23 @@ def _matching_targetinfo(self, target_filename, mapping):
 
 
 
+
+  def _targetinfo_match(self, targetinfo1, targetinfo2, match_custom_field=True):
+    if match_custom_field:
+      return (targetinfo1 == targetinfo2)
+
+    else:
+      targetinfo1_without_custom = copy.deepcopy(targetinfo1)
+      targetinfo2_without_custom = copy.deepcopy(targetinfo2)
+      targetinfo1_without_custom['fileinfo'].pop('custom', None)
+      targetinfo2_without_custom['fileinfo'].pop('custom', None)
+
+      return (targetinfo1_without_custom == targetinfo2_without_custom)
+
+
+
+
+
   def _target_matches_path_pattern(self, target_filename, path_patterns):
     for path_pattern in path_patterns:
       logger.debug('Interrogating pattern ' + repr(path_pattern) + 'for'