git cl: add plumbing command to get metadata about CLs in machine-readable form

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index 41bbb9800ecf68e8a24e5e9b0f9ce055009f8074..f10c196b93a83db5a5d2015195419feced1f9f52 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1448,6 +1448,14 @@ class Changelist(object):
   def GetStatus(self):
     return self._codereview_impl.GetStatus()
 
+  def IsOpen(self):
+    return self._codereview_impl.IsOpen()
+
+  def GetCQState(self):
+    state = self._codereview_impl.GetCQState()
+    assert state in _CQState.ALL_STATES
+    return state
+
   def GetCodereviewServer(self):
     return self._codereview_impl.GetCodereviewServer()
 
@@ -1483,6 +1491,14 @@ class _ChangelistCodereviewBase(object):
     """
     raise NotImplementedError()
 
+  def IsOpen(self):
+    """Returns True iff the issue is open."""
+    raise NotImplementedError()
+
+  def GetCQState(self):
+    """Returns CQ state (see _CQState)."""
+    raise NotImplementedError()
+
   def GetCodereviewServer(self):
     """Returns server URL without end slash, like "https://codereview.com"."""
     raise NotImplementedError()
@@ -1681,11 +1697,9 @@ class _RietveldChangelistImpl(_ChangelistCodereviewBase):
     except urllib2.HTTPError:
       return 'error'
 
-    if props.get('closed'):
-      # Issue is closed.
+    if not self.IsOpen():
       return 'closed'
-    if props.get('commit') and not props.get('cq_dry_run', False):
-      # Issue is in the commit queue.
+    if self.GetCQState() == _CQState.COMMIT:
       return 'commit'
 
     try:
@@ -1719,6 +1733,20 @@ class _RietveldChangelistImpl(_ChangelistCodereviewBase):
       return 'reply'
     return 'waiting'
 
+  def IsOpen(self, props=None):
+    if not props:
+      props = self.GetIssueProperties()
+    return not props.get('closed')
+
+  def GetCQState(self, props=None):
+    if not props:
+      props = self.GetIssueProperties()
+    if props.get('commit') and not props.get('cq_dry_run'):
+      return _CQState.COMMIT
+    if props.get('cq_dry_run'):
+      return _CQState.DRY_RUN
+    return _CQState.NONE
+
   def UpdateDescriptionRemote(self, description):
     return self.RpcServer().update_description(
         self.GetIssue(), self.description)
@@ -2191,16 +2219,11 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
     except httplib.HTTPException:
       return 'error'
 
-    if data['status'] in ('ABANDONED', 'MERGED'):
+    if not self.IsOpen(data=data):
       return 'closed'
 
-    cq_label = data['labels'].get('Commit-Queue', {})
-    if cq_label:
-      # Vote value is a stringified integer, which we expect from 0 to 2.
-      vote_value = cq_label.get('value', '0')
-      vote_text = cq_label.get('values', {}).get(vote_value, '')
-      if vote_text.lower() == 'commit':
-        return 'commit'
+    if self.GetCQState(data=data) == _CQState.COMMIT:
+      return 'commit'
 
     lgtm_label = data['labels'].get('Code-Review', {})
     if lgtm_label:
@@ -2222,6 +2245,25 @@ class _GerritChangelistImpl(_ChangelistCodereviewBase):
 
     return 'waiting'
 
+  def IsOpen(self, data=None):
+    if not data:
+      data = self._GetChangeDetail(['DETAILED_LABELS', 'CURRENT_REVISION'])
+    return data['status'] not in ('ABANDONED', 'MERGED')
+
+  def GetCQState(self, data=None):
+    if not data:
+      data = self._GetChangeDetail(['DETAILED_LABELS', 'CURRENT_REVISION'])
+    cq_label = data['labels'].get('Commit-Queue', {})
+    if cq_label:
+      # Vote value is a stringified integer, which we expect from 0 to 2.
+      vote_value = cq_label.get('value', '0')
+      vote_text = cq_label.get('values', {}).get(vote_value, '')
+      if vote_text.lower() == 'commit':
+        return _CQState.COMMIT
+      if vote_test.lower() == 'dry run':
+        return _CQState.DRY_RUN
+    return _CQState.NONE
+
   def GetMostRecentPatchset(self):
     data = self._GetChangeDetail(['CURRENT_REVISION'])
     return data['revisions'][data['current_revision']]['_number']
@@ -5059,6 +5101,34 @@ def CMDlol(parser, args):
   return 0
 
 
+def CMDplumbing(parser, args):
+  """Returns info about the CL in machine-readable form."""
+  parser.add_option('--json', help='Path to output JSON file')
+
+  auth.add_auth_options(parser)
+
+  _add_codereview_select_options(parser)
+  options, args = parser.parse_args(args)
+  _process_codereview_select_options(parser, options)
+
+  auth_config = auth.extract_auth_config_from_options(options)
+
+  cl = Changelist(auth_config=auth_config, codereview=options.forced_codereview)
+
+  result = {
+    'open': cl.IsOpen(),
+    'commit_queue': cl.GetCQState(),
+  }
+
+  if options.json:
+    with open(options.json, 'w') as f:
+      json.dump(result, f)
+  else:
+    print(json.dumps(result, sort_keys=True, indent=4))
+
+  return 0
+
+
 class OptionParser(optparse.OptionParser):
   """Creates the option parse and add --verbose support."""
   def __init__(self, *args, **kwargs):