--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebKitTools/Scripts/webkitpy/tool/commands/stepsequence.py	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,83 @@
+# Copyright (C) 2009 Google Inc. All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# 
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import webkitpy.tool.steps as steps
+
+from webkitpy.common.system.executive import ScriptError
+from webkitpy.common.checkout.scm import CheckoutNeedsUpdate
+from webkitpy.tool.bot.queueengine import QueueEngine
+from webkitpy.common.system.deprecated_logging import log
+
+
+class StepSequenceErrorHandler():
+    @classmethod
+    def handle_script_error(cls, tool, patch, script_error):
+        raise NotImplementedError, "subclasses must implement"
+
+    @classmethod
+    def handle_checkout_needs_update(cls, tool, state, options, error):
+        raise NotImplementedError, "subclasses must implement"
+
+
+class StepSequence(object):
+    def __init__(self, steps):
+        self._steps = steps or []
+
+    def options(self):
+        collected_options = [
+            steps.Options.parent_command,
+            steps.Options.quiet,
+        ]
+        for step in self._steps:
+            collected_options = collected_options + step.options()
+        # Remove duplicates.
+        collected_options = sorted(set(collected_options))
+        return collected_options
+
+    def _run(self, tool, options, state):
+        for step in self._steps:
+            step(tool, options).run(state)
+
+    def run_and_handle_errors(self, tool, options, state=None):
+        if not state:
+            state = {}
+        try:
+            self._run(tool, options, state)
+        except CheckoutNeedsUpdate, e:
+            log("Commit failed because the checkout is out of date.  Please update and try again.")
+            if options.parent_command:
+                command = tool.command_by_name(options.parent_command)
+                command.handle_checkout_needs_update(tool, state, options, e)
+            QueueEngine.exit_after_handled_error(e)
+        except ScriptError, e:
+            if not options.quiet:
+                log(e.message_with_output())
+            if options.parent_command:
+                command = tool.command_by_name(options.parent_command)
+                command.handle_script_error(tool, state, e)
+            QueueEngine.exit_after_handled_error(e)