generate a repo manifest from the DEPS file

This allows people to use repo to manage the checkout instead of gclient.
This helps when you're used to the standard repo+gerrit workflow that the
Android & Chromium OS projects use.

Change-Id: I8b720e7995af2a1a8c9ce2ee9aa6c2638441b4a1
Reviewed-on: https://chromium-review.googlesource.com/379736
Reviewed-by: Mark Mentovai <mark@chromium.org>

.gitignore

@@ -27,6 +27,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # Ignore other VCSs.
+.repo/
 .svn/
 
 # Ignore common compiled artifacts.

DEPS

@@ -72,4 +72,9 @@ hooks = [
                "--no-circular-check",
                "src/src/client/windows/breakpad_client.gyp"],
   },
+  {
+    # Keep the manifest up to date.
+    "action": ["python", "src/src/tools/python/deps-to-manifest.py",
+               "src/DEPS", "src/default.xml"],
+  },
 ]

default.xml

@@ -0,0 +1,53 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- AUTOGENERATED BY deps-to-manifest.py; DO NOT EDIT -->
+<manifest>
+
+  <default revision='refs/heads/master'
+           remote='chromium'
+           sync-c='true'
+           sync-j='8' />
+
+  <remote  name='github'
+           fetch='https://github.com/'
+           review='' />
+
+  <remote  name='chromium'
+           fetch='https://chromium.googlesource.com/'
+           review='https://chromium-review.googlesource.com' />
+
+  <project path='src'
+           name='breakpad/breakpad'
+           revision='refs/heads/master'
+           remote='chromium' />
+
+  <project path='src/src/tools/gyp'
+           name='external/gyp/'
+           revision='e8ab0833a42691cd2184bd4c45d779e43821d3e0'
+           remote='chromium' />
+
+  <project path='src/src/testing/gtest'
+           name='google/googletest.git'
+           revision='refs/tags/release-1.7.0'
+           remote='github' />
+
+  <project path='src/src/third_party/protobuf/protobuf'
+           name='google/protobuf.git'
+           revision='cb6dd4ef5f82e41e06179dcd57d3b1d9246ad6ac'
+           remote='github' />
+
+  <project path='src/src/third_party/lss'
+           name='linux-syscall-support/'
+           revision='3f6478ac95edf86cd3da300c2c0d34a438f5dbeb'
+           remote='chromium' />
+
+  <project path='src/src/third_party/glog'
+           name='google/glog.git'
+           revision='refs/tags/v0.3.4'
+           remote='github' />
+
+  <project path='src/src/testing'
+           name='google/googlemock.git'
+           revision='refs/tags/release-1.7.0'
+           remote='github' />
+
+</manifest>

src/tools/python/deps-to-manifest.py

@@ -0,0 +1,167 @@
+#!/usr/bin/python
+# Copyright 2016 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.
+
+"""Convert gclient's DEPS file to repo's manifest xml file."""
+
+from __future__ import print_function
+
+import argparse
+import os
+import sys
+
+
+REMOTES = {
+    'chromium': 'https://chromium.googlesource.com/',
+    'github': 'https://github.com/',
+}
+REVIEWS = {
+    'chromium': 'https://chromium-review.googlesource.com',
+}
+
+MANIFEST_HEAD = """<?xml version='1.0' encoding='UTF-8'?>
+<!-- AUTOGENERATED BY %(prog)s; DO NOT EDIT -->
+<manifest>
+
+  <default revision='refs/heads/master'
+           remote='chromium'
+           sync-c='true'
+           sync-j='8' />
+"""
+
+MANIFEST_REMOTE = """
+  <remote  name='%(name)s'
+           fetch='%(fetch)s'
+           review='%(review)s' />
+"""
+
+MANIFEST_PROJECT = """
+  <project path='%(path)s'
+           name='%(name)s'
+           revision='%(revision)s'
+           remote='%(remote)s' />
+"""
+
+MANIFEST_TAIL = """
+</manifest>
+"""
+
+
+def ConvertDepsToManifest(deps, manifest):
+  """Convert the |deps| file to the |manifest|."""
+  # Load the DEPS file data.
+  ctx = {}
+  execfile(deps, ctx)
+
+  new_contents = ''
+
+  # Write out the common header.
+  data = {
+      'prog': os.path.basename(__file__),
+  }
+  new_contents += MANIFEST_HEAD % data
+
+  # Write out the <remote> sections.
+  for name, fetch in REMOTES.items():
+    data = {
+        'name': name,
+        'fetch': fetch,
+        'review': REVIEWS.get(name, ''),
+    }
+    new_contents += MANIFEST_REMOTE % data
+
+  # Write out the main repo itself.
+  data = {
+      'path': 'src',
+      'name': 'breakpad/breakpad',
+      'revision': 'refs/heads/master',
+      'remote': 'chromium',
+  }
+  new_contents += MANIFEST_PROJECT % data
+
+  # Write out the <project> sections.
+  for path, url in ctx['deps'].items():
+    for name, fetch in REMOTES.items():
+      if url.startswith(fetch):
+        remote = name
+        break
+    else:
+      raise ValueError('Unknown DEPS remote: %s: %s' % (path, url))
+
+    # The DEPS url will look like:
+    # https://chromium.googlesource.com/external/gyp/@e8ab0833a42691cd2
+    remote_path, rev = url.split('@')
+    remote_path = remote_path[len(fetch):]
+
+    # If it's not a revision, assume it's a tag.  Repo wants full ref names.
+    if len(rev) != 40:
+      rev = 'refs/tags/%s' % rev
+
+    data = {
+        'path': path,
+        'name': remote_path,
+        'revision': rev,
+        'remote': remote,
+    }
+    new_contents += MANIFEST_PROJECT % data
+
+  # Write out the common footer.
+  new_contents += MANIFEST_TAIL
+
+  # See if the manifest has actually changed contents to avoid thrashing.
+  try:
+    old_contents = open(manifest).read()
+  except IOError:
+    # In case the file doesn't exist yet.
+    old_contents = ''
+  if old_contents != new_contents:
+    print('Updating %s due to changed %s' % (manifest, deps))
+    with open(manifest, 'w') as fp:
+      fp.write(new_contents)
+
+
+def GetParser():
+  """Return a CLI parser."""
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument('deps',
+                      help='The DEPS file to convert')
+  parser.add_argument('manifest',
+                      help='The manifest xml to generate')
+  return parser
+
+
+def main(argv):
+  """The main func!"""
+  parser = GetParser()
+  opts = parser.parse_args(argv)
+  ConvertDepsToManifest(opts.deps, opts.manifest)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))