add support for outputing json objects from list

ui/fixtures/cmd.basic.json

@@ -67,6 +67,11 @@
 	"cmd": [ "list", "newfile.txt" ],
 	"stdout_re": "dc:creator:\tJohn-Mark Gurney\nhashes:\tsha512:90f8342520f0ac57fb5a779f5d331c2fa87aa40f8799940257f9ba619940951e67143a8d746535ed0284924b2b7bc1478f095198800ba96d01847d7b56ca465c\nsig:\t.*\ntag:\t\n"
 },
+{
+	"title": "verify --json works",
+	"cmd": [ "list", "--json", "newfile.txt" ],
+	"stdout_check": [ { "dc:creator": [ "John-Mark Gurney" ], "hashes": [ "sha512:90f8342520f0ac57fb5a779f5d331c2fa87aa40f8799940257f9ba619940951e67143a8d746535ed0284924b2b7bc1478f095198800ba96d01847d7b56ca465c" ], "tag": [ "" ], "type": "metadata" } ]
+},
 {
 	"title": "add duplicate ms:tag's",
 	"cmd": [ "modify", "+ms:tag=foo", "+ms:tag=foo", "newfile.txt" ]

ui/medashare/cli.py

@@ -1426,8 +1426,11 @@ def cmd_list(options, persona, objstr, cache):
 				continue
 
 		for j in objstr.by_file(i):
-			for k, v in _iterdictlist(j):
-				print('%s:\t%s' % (k, v))
+			if options.json:
+				print(j.encode('json'))
+			else:
+				for k, v in _iterdictlist(j):
+					print('%s:\t%s' % (k, v))
 
 	if exit:
 		sys.exit(exit)
@@ -1810,6 +1813,8 @@ def main():
 	parser_auto.set_defaults(func=cmd_auto)
 
 	parser_list = subparsers.add_parser('list', help='list tags on file(s)')
+	parser_list.add_argument('--json', action='store_true',
+	    help='output data as series of JSON objects')
 	parser_list.add_argument('files', nargs='+',
 	    help='files to modify')
 	parser_list.set_defaults(func=cmd_list)
@@ -2478,7 +2483,7 @@ class _TestCases(unittest.TestCase):
 
 	def objcompare(self, fullobjs, partialobjs):
 		fullobjs = list(fullobjs)
-		#_debprint('objs:', repr(fullobjs))
+		#_debprint('objs:', repr(fullobjs), repr(partialobjs))
 		self.assertEqual(len(fullobjs), len(partialobjs))
 
 		missing = []