add --only-sponsors flag

Filter results based on companies that sponsor the foundation at gold
or platinum level.

Change-Id: Ieacdfc3f512fc102656d3bcfcd9fccdacac20f43
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

goal_tools/sponsors.py

@@ -45,3 +45,7 @@ class Sponsors:
         if name.lower() in self._names:
             return name
         return '*other'
+
+    @functools.lru_cache(maxsize=1024)
+    def __contains__(self, name):
+        return name.lower() in self._names

goal_tools/who_helped/report.py

@@ -32,13 +32,20 @@ class ContributionsReportBase(lister.Lister):
             action='append',
             help='filter to only include specific roles (may be repeated)',
         )
-        parser.add_argument(
+        sponsor_group = parser.add_mutually_exclusive_group()
+        sponsor_group.add_argument(
             '--highlight-sponsors',
             default=False,
             action='store_true',
             help=('highlight sponsor organizations and '
                   'combine stats for others'),
         )
+        sponsor_group.add_argument(
+            '--only-sponsors',
+            default=False,
+            action='store_true',
+            help=('show only stats for sponsor organizations'),
+        )
         parser.add_argument(
             '--sponsor-level',
             default='all',
@@ -97,6 +104,15 @@ class ContributionsReportBase(lister.Lister):
         if ignore_teams:
             data = (d for d in data if d['Team'].lower() not in ignore_teams)
 
+        if parsed_args.only_sponsors:
+            sponsor_map = sponsors.Sponsors(parsed_args.sponsor_level)
+
+            data = (
+                d
+                for d in data
+                if d['Organization'] in sponsor_map
+            )
+
         ignore_tags = set(parsed_args.ignore_tag)
         if ignore_tags:
             team_data = governance.Governance(