add support for diff in file settings

this allows modules to report on what specifically changed when using
common file functions

lib/ansible/module_utils/basic.py

@@ -751,7 +751,7 @@ class AnsibleModule(object):
         context = self.selinux_default_context(path)
         return self.set_context_if_different(path, context, False)
 
-    def set_context_if_different(self, path, context, changed):
+    def set_context_if_different(self, path, context, changed, diff=None):
 
         if not HAVE_SELINUX or not self.selinux_enabled():
             return changed
@@ -772,6 +772,14 @@ class AnsibleModule(object):
                         new_context[i] = cur_context[i]
 
         if cur_context != new_context:
+            if diff is not None:
+                if 'before' not in diff:
+                    diff['before'] = {}
+                diff['before']['secontext'] = cur_context
+                if 'after' not in diff:
+                    diff['after'] = {}
+                diff['after']['secontext'] = new_context
+
             try:
                 if self.check_mode:
                     return True
@@ -785,7 +793,7 @@ class AnsibleModule(object):
             changed = True
         return changed
 
-    def set_owner_if_different(self, path, owner, changed):
+    def set_owner_if_different(self, path, owner, changed, diff=None):
         path = os.path.expanduser(path)
         if owner is None:
             return changed
@@ -798,6 +806,15 @@ class AnsibleModule(object):
             except KeyError:
                 self.fail_json(path=path, msg='chown failed: failed to look up user %s' % owner)
         if orig_uid != uid:
+
+            if diff is not None:
+                if 'before' not in diff:
+                    diff['before'] = {}
+                diff['before']['owner'] = orig_uid
+                if 'after' not in diff:
+                    diff['after'] = {}
+                diff['after']['owner'] = uid
+
             if self.check_mode:
                 return True
             try:
@@ -807,7 +824,7 @@ class AnsibleModule(object):
             changed = True
         return changed
 
-    def set_group_if_different(self, path, group, changed):
+    def set_group_if_different(self, path, group, changed, diff=None):
         path = os.path.expanduser(path)
         if group is None:
             return changed
@@ -820,6 +837,15 @@ class AnsibleModule(object):
             except KeyError:
                 self.fail_json(path=path, msg='chgrp failed: failed to look up group %s' % group)
         if orig_gid != gid:
+
+            if diff is not None:
+                if 'before' not in diff:
+                    diff['before'] = {}
+                diff['before']['group'] = orig_gid
+                if 'after' not in diff:
+                    diff['after'] = {}
+                diff['after']['group'] = gid
+
             if self.check_mode:
                 return True
             try:
@@ -829,7 +855,7 @@ class AnsibleModule(object):
             changed = True
         return changed
 
-    def set_mode_if_different(self, path, mode, changed):
+    def set_mode_if_different(self, path, mode, changed, diff=None):
         path = os.path.expanduser(path)
         path_stat = os.lstat(path)
 
@@ -851,6 +877,15 @@ class AnsibleModule(object):
         prev_mode = stat.S_IMODE(path_stat.st_mode)
 
         if prev_mode != mode:
+
+            if diff is not None:
+                if 'before' not in diff:
+                    diff['before'] = {}
+                diff['before']['mode'] = prev_mode
+                if 'after' not in diff:
+                    diff['after'] = {}
+                diff['after']['mode'] = mode
+
             if self.check_mode:
                 return True
             # FIXME: comparison against string above will cause this to be executed
@@ -984,27 +1019,27 @@ class AnsibleModule(object):
         or_reduce = lambda mode, perm: mode | user_perms_to_modes[user][perm]
         return reduce(or_reduce, perms, 0)
 
-    def set_fs_attributes_if_different(self, file_args, changed):
+    def set_fs_attributes_if_different(self, file_args, changed, diff=None):
         # set modes owners and context as needed
         changed = self.set_context_if_different(
-            file_args['path'], file_args['secontext'], changed
+            file_args['path'], file_args['secontext'], changed, diff
         )
         changed = self.set_owner_if_different(
-            file_args['path'], file_args['owner'], changed
+            file_args['path'], file_args['owner'], changed, diff
         )
         changed = self.set_group_if_different(
-            file_args['path'], file_args['group'], changed
+            file_args['path'], file_args['group'], changed, diff
         )
         changed = self.set_mode_if_different(
-            file_args['path'], file_args['mode'], changed
+            file_args['path'], file_args['mode'], changed, diff
         )
         return changed
 
-    def set_directory_attributes_if_different(self, file_args, changed):
-        return self.set_fs_attributes_if_different(file_args, changed)
+    def set_directory_attributes_if_different(self, file_args, changed, diff=None):
+        return self.set_fs_attributes_if_different(file_args, changed, diff)
 
-    def set_file_attributes_if_different(self, file_args, changed):
-        return self.set_fs_attributes_if_different(file_args, changed)
+    def set_file_attributes_if_different(self, file_args, changed, diff=None):
+        return self.set_fs_attributes_if_different(file_args, changed, diff)
 
     def add_path_info(self, kwargs):
         '''