Added `cros_pin` CrOS pin-bump tool.

infra/tools/cros_pin/checkout.py

Index: infra/tools/cros_pin/checkout.py
diff --git a/infra/tools/cros_pin/checkout.py b/infra/tools/cros_pin/checkout.py
new file mode 100644
index 0000000000000000000000000000000000000000..5d7c053c043f0855e948d26622446d151bcdd94b
--- /dev/null
+++ b/infra/tools/cros_pin/checkout.py
@@ -0,0 +1,93 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import os
+import shutil
+import tempfile
+
+
+from infra.tools.cros_pin import execute
+from infra.tools.cros_pin.logger import LOGGER
+
+
+class Checkout(object):

[ghost stip (do not use), 2015/10/15 20:02:54]

can you make this a context manager?

just add __enter__() and __exit__() as in
https://docs.python.org/2/reference/datamodel.html#object.__enter__

then you can do

with Checkout('chillpath') as checkout:
  do_stuff(checkout.subpath('yolo'))

and it will get deleted automatically when you exit the context manager

[dnj, 2015/10/15 21:06:41]

Yeah! I kind of have something going like that in `checkout_for_args`, but I'll
move it closer to checkout class.

with Checkout.use(...) as c:
  ...

+  """Checkout is a managed root checkout directory."""
+
+  GCLIENT_TEMPLATE = """
+solutions = [
+  {
+    "url": "https://chromium.googlesource.com/chromium/tools/build.git",
+    "managed": False,
+    "name": "build",
+    "deps_file": ".DEPS.git",
+  },
+  {
+    "url": "https://chrome-internal.googlesource.com/chrome/tools/build.git",
+    "managed": False,
+    "name": "build_internal",
+    "deps_file": ".DEPS.git",
+  },
+]
+"""
+
+  def __init__(self, path, delete=False):
+    self._path = path
+    self._delete = delete
+
+  @property
+  def path(self):
+    return self._path
+
+  def subpath(self, *components):
+    return os.path.join(self._path, *components)
+
+  def teardown(self):
+    if self._delete:
+      self._destroy_directory(self._path)
+
+  @classmethod
+  def create(cls, path=None):
+    """Creates a new Checkout using the specified path.
+
+    Args:
+      path (str): The path of the checkout to use. If None, a temporary
+          checkout will be created.
+    """
+    delete = False
+    if path:
+      if os.path.isdir(path):
+        return cls(path, delete=False)
+      os.makedirs(path)
+    else:
+      path = tempfile.mkdtemp(prefix='tmp_cros_pin')
+      delete = True
+
+    try:
+      cls.fetch(path)
+      c = cls(path, delete=delete)
+      path = None # Signal our "finally" clause not to clean up here.
+    finally:
+      if path:
+        cls._destroy_directory(path)
+    return c
+
+  @classmethod
+  def fetch(cls, path):
+    LOGGER.info("Fetching => %s (This can take a while.)", path)
+    gclient_path = os.path.join(path, '.gclient')
+    with open(gclient_path, 'w') as fd:
+      fd.write(cls.GCLIENT_TEMPLATE)
+
+    execute.check_call(
+        ['gclient', 'sync', '--nohooks', '--noprehooks'],
+        cwd=path)
+
+  @staticmethod
+  def _destroy_directory(d):
+    LOGGER.debug('Destorying directory: %s', d)
+    def log_failure(_function, path, excinfo):
+      LOGGER.warning('Failed when destroying [%s]: %s',
+                     path, excinfo[1].message)
+    shutil.rmtree(d, onerror=log_failure)