Alter hooks to call into depot_tools lib.

This new method allows us to install pre-cl-upload
and pre-cl-dcommit hook files which should rarely need
to be updated (with luck).  These hooks load the real
hooks lib from depot_tools which takes over execution
of the presubmit tests.

BUG=5339
TEST=hooks are run by git cl upload/dcommit and behave
as expected
Review URL: http://codereview.chromium.org/243118

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@28409 0039d316-1c4b-4281-b951-d872f2087c98

git-cl-upload-hook

@@ -4,8 +4,6 @@
 # found in the LICENSE file.
 
 import os
-import re
-import subprocess
 import sys
 
 # Find depot_tools in PATH, append it to sys.path so we can import.
@@ -16,60 +14,12 @@ for path in paths.split(':'):
   sys.path.append(path)
   break
 
-import gclient_scm
-import presubmit_support
-
-def Backquote(cmd, cwd=None):
-  """Like running `cmd` in a shell script."""
-  return subprocess.Popen(cmd,
-                          cwd=cwd,
-                          stdout=subprocess.PIPE).communicate()[0].strip()
-
-
-class ChangeOptions:
-  def __init__(self, commit=None, upstream_branch=None):
-    self.commit = commit
-    self.verbose = None
-    self.default_presubmit = None
-    self.may_prompt = None
-
-    root = os.path.abspath(Backquote(['git', 'rev-parse', '--show-cdup']))
-    if not root:
-      raise Exception("Could not get root directory.")
-    log = Backquote(['git', 'show', '--name-only',
-                     '--pretty=format:%H%n%s%n%n%b'])
-    m = re.match(r'^(\w+)\n(.*)$', log, re.MULTILINE|re.DOTALL)
-    if not m:
-      raise Exception("Could not parse log message: %s" % log)
-    name = m.group(1)
-    description = m.group(2)
-    files = gclient_scm.CaptureGitStatus([root], upstream_branch)
-    issue = Backquote(['git', 'cl', 'status', '--field=id'])
-    patchset = None
-    self.change = presubmit_support.GitChange(name, description, root, files,
-                                              issue, patchset)
-
+import git_cl_hooks
 
 # Ensure we were called with the necessary number of arguments.
 program_name = os.path.basename(sys.argv[0])
-if len(sys.argv) < 2:
+if len(sys.argv) != 2:
   raise Exception("usage: %s [upstream branch]" % program_name)
 
-# Get arguments from how we were called.
-commit = (program_name == 'pre-cl-dcommit')
-upstream_branch = sys.argv[1]
-
-# Create our options based on the command-line args and the current checkout.
-options = ChangeOptions(commit=commit, upstream_branch=upstream_branch)
-
-# Run the presubmit checks.
-if presubmit_support.DoPresubmitChecks(options.change,
-                                       options.commit,
-                                       options.verbose,
-                                       sys.stdout,
-                                       sys.stdin,
-                                       options.default_presubmit,
-                                       options.may_prompt):
-  sys.exit(0)
-else:
-  sys.exit(1)
+# Run the hooks library with our arguments.
+exec git_cl_hooks.RunHooks(hook_name=program_name, upstream_branch=sys.argv[1])

git_cl_hooks.py

+# Copyright (c) 2009 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 re
+import subprocess
+import sys
+
+# Imported from depot_tools.
+import gclient_scm
+import presubmit_support
+
+def Backquote(cmd, cwd=None):
+  """Like running `cmd` in a shell script."""
+  return subprocess.Popen(cmd,
+                          cwd=cwd,
+                          stdout=subprocess.PIPE).communicate()[0].strip()
+
+
+class ChangeOptions:
+  def __init__(self, commit=None, upstream_branch=None):
+    self.commit = commit
+    self.verbose = None
+    self.default_presubmit = None
+    self.may_prompt = None
+
+    root = os.path.abspath(Backquote(['git', 'rev-parse', '--show-cdup']))
+    if not root:
+      raise Exception("Could not get root directory.")
+    log = Backquote(['git', 'show', '--name-only',
+                     '--pretty=format:%H%n%s%n%n%b'])
+    m = re.match(r'^(\w+)\n(.*)$', log, re.MULTILINE|re.DOTALL)
+    if not m:
+      raise Exception("Could not parse log message: %s" % log)
+    name = m.group(1)
+    description = m.group(2)
+    files = gclient_scm.CaptureGitStatus([root], upstream_branch)
+    issue = Backquote(['git', 'cl', 'status', '--field=id'])
+    patchset = None
+    self.change = presubmit_support.GitChange(name, description, root, files,
+                                              issue, patchset)
+
+
+def RunHooks(hook_name, upstream_branch):
+  commit = (hook_name == 'pre-cl-dcommit')
+
+  # Create our options based on the command-line args and the current checkout.
+  options = ChangeOptions(commit=commit, upstream_branch=upstream_branch)
+
+  # Run the presubmit checks.
+  if presubmit_support.DoPresubmitChecks(options.change,
+                                         options.commit,
+                                         options.verbose,
+                                         sys.stdout,
+                                         sys.stdin,
+                                         options.default_presubmit,
+                                         options.may_prompt):
+    sys.exit(0)
+  else:
+    sys.exit(1)