Split out the big chromite shell 'main.py' into lots of subfiles.

shell/subcmd.py

Index: shell/subcmd.py
diff --git a/shell/subcmd.py b/shell/subcmd.py
index b93f65d5a4b826acea9e0bc8e0b716b577bf63c6..e1e2009465a64112d3c4cf5264e728e0bf541956 100644
--- a/shell/subcmd.py
+++ b/shell/subcmd.py
@@ -1,10 +1,17 @@
-#!/usr/bin/python
 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """ChromiteCmd abstract class and related functions."""
 
+# Python imports
+import os
+import sys
+
+# Local imports
+import chromite.lib.cros_build_lib as cros_lib
+from chromite.shell import utils
+
 
 class ChromiteCmd(object):
   """The abstract base class of commands listed at the top level of chromite."""
@@ -27,3 +34,94 @@ class ChromiteCmd(object):
     """
     # Must be implemented by subclass...
     raise NotImplementedError()
+
+
+class WrappedChrootCmd(ChromiteCmd):
+  """Superclass for any command that is simply wrapped by chromite.
+
+  These are commands where:
+  - We parse the command line only enough to figure out what board they
+    want.  All othe command line parsing is handled by the wrapped command.
+    Because of this, the board name _needs_ to be specified first.
+  - Everything else (arg parsing, help, etc) is handled by the wrapped command.
+    The usage string will be a little messed up, but hopefully that's OK.
+  """
+
+  def __init__(self, target_cmd, host_cmd, need_args=False):
+    """WrappedChrootCmd constructor.
+
+    Args:
+      target_cmd: We'll put this at the start of argv when calling a target
+          command.  We'll substiture %s with the target.
+          Like - ['my_command-%s'] or ['my_command', '--board=%s']
+      host_cmd: We'll put this at the start of argv when calling a host command.
+          Like - ['my_command'] or ['sudo', 'my_command']
+      need_args: If True, we'll prompt for arguments if they weren't specified.
+          This makes the most sense when someone runs chromite with no arguments
+          and then walks through the menus.  It's not ideal, but less sucky than
+          just quitting.
+    """
+    # Call superclass constructor.
+    super(WrappedChrootCmd, self).__init__()
+
+    # Save away params for use later in Run().
+    self._target_cmd = target_cmd
+    self._host_cmd = host_cmd
+    self._need_args = need_args
+
+  def Run(self, raw_argv, chroot_config=None, argv=None, build_config=None):
+    """Run the command.
+
+    Args:
+      raw_argv: Command line arguments, including this command's name, but not
+          the chromite command name or chromite options.
+      chroot_config: A SafeConfigParser for the chroot config; or None chromite
+          was called from within the chroot.
+      argv: None when called normally, but contains argv with board stripped off
+          if we call ourselves with utils.EnterChroot().
+      build_config: None when called normally, but contains the SafeConfigParser
+          for the build config if we call ourselves with utils.EnterChroot().
+          Note that even when called through utils.EnterChroot(), could still
+          be None if user chose 'HOST' as the target.
+    """
+    # If we didn't get called through EnterChroot, we need to read the build
+    # config.
+    if argv is None:
+      # We look for the build config without calling OptionParser.  This means
+      # that the board _needs_ to be first (if it's specified) and all options
+      # will be passed straight to our subcommand.
+      argv, build_config = utils.GetBuildConfigFromArgs(raw_argv[1:])
+
+    # Enter the chroot if needed...
+    if not cros_lib.IsInsideChroot():
+      utils.EnterChroot(chroot_config, (self, 'Run'), raw_argv, argv=argv,
+                        build_config=build_config)
+    else:
+      # We'll put CWD as src/scripts when running the command.  Since everyone
+      # running by hand has their cwd there, it is probably the safest.
+      cwd = os.path.join(utils.SRCROOT_PATH, 'src', 'scripts')
+
+      # Get command to call.  If build_config is None, it means host.
+      if build_config is None:
+        argv_prefix = self._host_cmd
+      else:
+        # Make argv_prefix w/ target.
+        target_name = build_config.get('BUILD', 'target')
+        argv_prefix = [arg % target_name for arg in self._target_cmd]
+
+      # Not a great way to to specify arguments, but works for now...  Wrapped
+      # commands are not wonderful interfaces anyway...
+      if self._need_args and not argv:
+        while True:
+          sys.stderr.write('arg %d (blank to exit): ' % (len(argv)+1))
+          arg = raw_input()
+          if not arg:
+            break
+          argv.append(arg)
+
+      # Add the prefix...
+      argv = argv_prefix + argv
+
+      # Run, ignoring errors since some commands (ahem, cros_workon) seem to
+      # return errors from things like --help.
+      cros_lib.RunCommand(argv, cwd=cwd, ignore_sigint=True, error_ok=True)