Create a tool to save a pinned dep file for the current sync.

src/scripts/make_relative_solution

Index: src/scripts/make_relative_solution
diff --git a/src/scripts/make_relative_solution b/src/scripts/make_relative_solution
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+#!/usr/bin/python
+#
+# Copyright (c) 2010 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.
+
+"""Generates a pinned solutions file with relative git repository URLs.
+
+make_relative_solution reads a pinned solution file generated by
+'gclient revinfo --snapshot' and writes to stdout a pinned solution file
+with relative git repository URLs.
+
+
+The resulting solution file can be used to check out a fixed version of
+a gclient set of repositories.  The base URL to fetch from can be changed
+by editing one line in the generated solution file.
+"""
+
+import optparse
+import sys
+
+
+def ReadSnapshot(filename):
+  """Reads a gclient revinfo snapshot file.
+
+  Minimal verification of the structure of the file is performed.
+
+  Args:
+    filename: The name of a snapshot file to read.
+
+  Returns:
+    The solutions array parsed from the snapshot file.
+  """
+
+  env = {}
+  execfile(filename, env)
+
+  assert 'solutions' in env
+  assert env['solutions']
+
+  return env['solutions']
+
+
+def BaseRepository(url):
+  """Finds the base repository path.
+
+  This only works if the top level repository is not in a subdirectory relative
+  to the other repositories on the server.
+
+  Args:
+    url: git repository url
+
+  Returns:
+    The prefix of the URL that does not contain the repository name and SHA.
+  """
+
+  base, versioned_repository = url.rsplit('/', 1)
+
+  assert base and versioned_repository
+  return base
+
+
+def WriteBaseURL(base, solution):
+  print '  "%s": "%s",' % (solution['name'], base)
+
+
+def IsRelativeRepository(base, url):
+  return url.startswith(base)
+
+
+def RelativeRepository(base, url):
+  if IsRelativeRepository(base, url):
+    return url[len(base):]
+  else:
+    return url
+
+
+def RelativeDep(base, dep):
+  path, repository = dep
+
+  return (path,
+          RelativeRepository(base, repository),
+          IsRelativeRepository(base, repository))
+
+
+def RelativeDeps(base, solution):
+  return [RelativeDep(base, dep) for dep in solution['custom_deps'].items()]
+
+
+def WritePinnedDep(name, dep, indent):
+  """Writes a pinned dep.
+
+  The output is indented so that the URLs all line up for ease of reading.  If
+  the dep is for a relative git repository then we emit the base_url lookup as
+  well.
+
+  Args:
+    name:   The name of the solution that is being written out.
+    dep:    The relative dep that is to be written out.
+    indent: The total number of characters to use for the path component.
+
+  Returns:
+    Nothing
+  """
+
+  path, repository, relative = dep
+  remainder = path.partition('/')[2]
+  spaces = indent - len(path)
+
+  if remainder == 'deps':
+    return
+
+  if relative:
+    print '      "%s": %*sbase_url["%s"] + "%s",' % (path,
+                                                     spaces, '',
+                                                     name,
+                                                     repository)
+  else:
+    print '      "%s": %*s"%s",' % (path,
+                                    spaces, '',
+                                    repository)
+
+
+def WritePinnedSolution(solution):
+  """Writes out a pinned and solution file with relative repository paths.
+
+  The relative repository paths make it easier for a user to modify where
+  they are pulling source from.
+
+  Args:
+    solution: gclient solution object.
+
+  Returns:
+    Nothing
+  """
+
+  base = BaseRepository(solution['url'])
+  url = RelativeRepository(base, solution['url'])
+  deps = RelativeDeps(base, solution)
+  indent = max(len(dep[0]) for dep in deps)
+
+  deps.sort(key=lambda dep: dep[1])
+
+  print ('  { "name"        : "%s",\n'
+         '    "url"         : base_url["%s"] + "%s",\n'
+         '    "custom_deps" : {') % (solution['name'],
+                                     solution['name'],
+                                     url)
+
+  for dep in deps:
+    WritePinnedDep(solution['name'], dep, indent)
+
+  print ('    },\n'
+         '  },')
+
+
+def main(argv):
+  usage = 'Usage: %prog [options] filename'
+  option_parser = optparse.OptionParser(usage=usage)
+  option_parser.disable_interspersed_args()
+  option_parser.add_option('-s', '--substitute',
+                           action='store_true',
+                           dest='substitute',
+                           default=False,
+                           help='substitute a new base git URL')
+  option_parser.add_option('-b', '--base',
+                           dest='base',
+                           default='http://src.chromium.org/git',
+                           metavar='URL',
+                           help='base git URL to substitute [%default]')
+
+  options, args = option_parser.parse_args(argv[1:])
+
+  if len(args) != 1:
+    option_parser.print_help()
+    return 1
+
+  filename = args.pop(0)
+  solutions = ReadSnapshot(filename)
+
+  print ('#\n'
+         '# Autogenerated pinned gclient solution file.  This file was\n'
+         '# created by running make_relative_solution.\n'
+         '#\n'
+         '\n'
+         'base_url = {')
+
+  for solution in solutions:
+    if options.substitute:
+      base = options.base
+    else:
+      base = BaseRepository(solution['url'])
+
+    WriteBaseURL(base, solution)
+
+  print ('}\n'
+         '\n'
+         'solutions = [')
+
+  for solution in solutions:
+    WritePinnedSolution(solution)
+
+  print ']\n'
+
+
+if __name__ == '__main__':
+  main(sys.argv)