Add the "diffmanifests" command

This command allows a deeper diff between two manifest projects.
In addition to changed projects, it displays the logs of the
commits between both revisions for each project.

Change-Id: I86d30602cfbc654f8c84db2be5d8a30cb90f1398
Signed-off-by: Julien Campergue <julien.campergue@parrot.com>

project.py

@@ -1100,6 +1100,23 @@ class Project(object):
     for copyfile in self.copyfiles:
       copyfile._Copy()
 
+  def GetCommitRevisionId(self):
+    """Get revisionId of a commit.
+
+    Use this method instead of GetRevisionId to get the id of the commit rather
+    than the id of the current git object (for example, a tag)
+
+    """
+    if not self.revisionExpr.startswith(R_TAGS):
+      return self.GetRevisionId(self._allrefs)
+
+    try:
+      return self.bare_git.rev_list(self.revisionExpr, '-1')[0]
+    except GitError:
+      raise ManifestInvalidRevisionError(
+        'revision %s in %s not found' % (self.revisionExpr,
+                                         self.name))
+
   def GetRevisionId(self, all_refs=None):
     if self.revisionId:
       return self.revisionId
@@ -2187,6 +2204,43 @@ class Project(object):
   def _allrefs(self):
     return self.bare_ref.all
 
+  def _getLogs(self, rev1, rev2, oneline=False, color=True):
+    """Get logs between two revisions of this project."""
+    comp = '..'
+    if rev1:
+      revs = [rev1]
+      if rev2:
+        revs.extend([comp, rev2])
+      cmd = ['log', ''.join(revs)]
+      out = DiffColoring(self.config)
+      if out.is_on and color:
+        cmd.append('--color')
+      if oneline:
+        cmd.append('--oneline')
+
+      try:
+        log = GitCommand(self, cmd, capture_stdout=True, capture_stderr=True)
+        if log.Wait() == 0:
+          return log.stdout
+      except GitError:
+        # worktree may not exist if groups changed for example. In that case,
+        # try in gitdir instead.
+        if not os.path.exists(self.worktree):
+          return self.bare_git.log(*cmd[1:])
+        else:
+          raise
+    return None
+
+  def getAddedAndRemovedLogs(self, toProject, oneline=False, color=True):
+    """Get the list of logs from this revision to given revisionId"""
+    logs = {}
+    selfId = self.GetRevisionId(self._allrefs)
+    toId = toProject.GetRevisionId(toProject._allrefs)
+
+    logs['added'] = self._getLogs(selfId, toId, oneline=oneline, color=color)
+    logs['removed'] = self._getLogs(toId, selfId, oneline=oneline, color=color)
+    return logs
+
   class _GitGetByExec(object):
     def __init__(self, project, bare, gitdir):
       self._project = project