Add support for reading state data from stdin.

apachedex/__init__.py

@@ -993,10 +993,12 @@ def main():
   parser.add_argument('-Q', dest='extra_quiet', action='store_true',
     help='Suppress progress indication (file being parsed, lines counter). '
       'Does not imply -q.')
-  parser.add_argument('--state-file', nargs='+', default=[], type=file,
-    help='Use given JSON files as initial state. Mixing files generated with '
-      'different parameters is allowed, but no correction is made. Output may '
-      'be unusable (ex: different --apdex, different --period, ...).')
+  parser.add_argument('--state-file', nargs='+', default=[],
+    help='Use given JSON files as initial state. Use - for stdin. Loading'
+      'multiple files through stdin is not possible). Mixing '
+      'files generated with different parameters is allowed, but no '
+      'correction is made. Output may be unusable (ex: different --apdex, '
+      'different --period, ...).')
 
   group = parser.add_argument_group('generated content')
   group.add_argument('-a', '--apdex', default=1.0, type=float,
@@ -1132,8 +1134,16 @@ def main():
   error_detail = args.error_detail
   file_count = len(infile_list)
   per_site = {}
-  for state_file in args.state_file:
-    print >> sys.stderr, 'Loading', state_file.name, '...',
+  if '-' in args.state_file and '-' in infile_list:
+    print >> sys.stderr, 'stdin cannot be used both as log and state input.'
+    sys.exit(1)
+  for state_file_name in args.state_file:
+    print >> sys.stderr, 'Loading', state_file_name, '...',
+    if state_file_name == '-':
+      state_file = sys.stdin
+    else:
+      state_file = open(state_file_name)
+    with state_file:
       load_start = time.time()
       state = json.load(state_file, encoding='ascii')
       for url, site_state in state: