rebase: Automatically rebase branch on upstrea

  Usage: repo rebase [[-i] <project>...]

Rebases the current topic branch of the specified (or all)
projects against the appropriate upstream.

Note: Interactive rebase is currently only supported when
exactly one project is specified on the command line.

Change-Id: I7376e35f27a6585149def82938c1ca99f36db2c4
Signed-off-by: Shawn O. Pearce <sop@google.com>

subcmds/rebase.py

@@ -0,0 +1,75 @@
+#
+# Copyright (C) 2010 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+from command import Command
+from git_command import GitCommand
+from git_refs import GitRefs, HEAD, R_HEADS, R_TAGS, R_PUB, R_M
+from error import GitError
+
+class Rebase(Command):
+  common = True
+  helpSummary = "Rebase local branches on upstream branch"
+  helpUsage = """
+%prog {[<project>...] | -i <project>...}
+"""
+  helpDescription = """
+'%prog' uses git rebase to move local changes in the current topic branch to
+the HEAD of the upstream history, useful when you have made commits in a topic
+branch but need to incorporate new upstream changes "underneath" them.
+"""
+
+  def _Options(self, p):
+    p.add_option('-i', '--interactive',
+                dest="interactive", action="store_true",
+                help="interactive rebase (single project only)")
+
+  def Execute(self, opt, args):
+    all = self.GetProjects(args)
+    one_project = len(all) == 1
+
+    if opt.interactive and not one_project:
+      print >>sys.stderr, 'error: interactive rebase not supported with multiple projects'
+      return -1
+
+    for project in all:
+      cb = project.CurrentBranch
+      if not cb:
+        if one_project:
+          print >>sys.stderr, "error: project %s has a detatched HEAD" % project.name
+          return -1
+        # ignore branches with detatched HEADs
+        continue
+
+      upbranch = project.GetBranch(cb)
+      if not upbranch.LocalMerge:
+        if one_project:
+          print >>sys.stderr, "error: project %s does not track any remote branches" % project.name
+          return -1
+        # ignore branches without remotes
+        continue
+
+      upstream = project.GetRevisionId()
+
+      args = ["rebase"]
+      if opt.interactive:
+        args.append("-i")
+      args.append(upstream)
+
+      print '# project %s: rebasing branch %s -> %s (%s)' % (
+        project.relpath, cb, upbranch.LocalMerge, upstream[0:7])
+      if GitCommand(project, args).Wait() != 0:
+        return -1