Bug 1460912 - [testing/profiles] Add a ./profile rm subcommand for removing prefs from a profile r=rwood

Usage is:
./profile rm <profile> [<file>]

The file is a list of prefs, one per line, to remove. The file defaults to stdin, so the culmination
of the last three commits is the ability to do:

./profile diff reftest common -f names -k same | ./profile rm reftest

The above command will remove from the reftest profile, the prefs that are identical in both
reftest and common. This method is quicker and less error prone than doing it manually (which
was how I was doing this previously).

MozReview-Commit-ID: Je0JjFXoora

--HG--
extra : rebase_source : 38dae2dcdc3986910cfcd5091f7fc968bf8cc22a

testing/profiles/profile

@@ -178,12 +178,7 @@ def diff(a, b, fmt, limit_key):
     return format_diff(results, fmt, limit_key)
 
 
-def sort_file(path):
-    """Sort the given pref file alphabetically, preserving preceding comments
-    that start with '//'.
-
-    :param path: Path to the preference file to sort.
-    """
+def read_with_comments(path):
     with open(path, 'r') as fh:
         lines = fh.readlines()
 
@@ -204,12 +199,21 @@ def sort_file(path):
             continue
 
         result.append([line])
+    return result
 
+
+def sort_file(path):
+    """Sort the given pref file alphabetically, preserving preceding comments
+    that start with '//'.
+
+    :param path: Path to the preference file to sort.
+    """
+    result = read_with_comments(path)
     result = sorted(result, key=lambda x: x[-1])
     result = chain(*result)
 
     with open(path, 'w') as fh:
-        fh.write('\n'.join(result))
+        fh.write('\n'.join(result) + '\n')
 
 
 def sort(profile):
@@ -236,6 +240,28 @@ def show(suite):
         print("{}: {}".format(k, repr(v)))
 
 
+def rm(profile, pref_file):
+    if pref_file == '-':
+        lines = sys.stdin.readlines()
+    else:
+        with open(pref_file, 'r') as fh:
+            lines = fh.readlines()
+
+    lines = [l.strip() for l in lines if l.strip()]
+    if not lines:
+        return
+
+    def filter_line(content):
+        return not any(line in content[-1] for line in lines)
+
+    path = os.path.join(here, profile, 'user.js')
+    contents = read_with_comments(path)
+    contents = filter(filter_line, contents)
+    contents = chain(*contents)
+    with open(path, 'w') as fh:
+        fh.write('\n'.join(contents))
+
+
 def cli(args=sys.argv[1:]):
     parser = ArgumentParser()
     subparsers = parser.add_subparsers()
@@ -261,6 +287,12 @@ def cli(args=sys.argv[1:]):
     show_parser.add_argument('suite', help="Name of suite to show arguments for.")
     show_parser.set_defaults(func=show)
 
+    rm_parser = subparsers.add_parser('rm')
+    rm_parser.add_argument('profile', help="Name of the profile to remove prefs from.")
+    rm_parser.add_argument('--pref-file', default='-', help="File containing a list of pref "
+                           "substrings to delete (default: stdin)")
+    rm_parser.set_defaults(func=rm)
+
     args = vars(parser.parse_args(args))
     func = args.pop('func')
     func(**args)