Pull in Chromium dependencies from HEAD

pipa/build/gitdeps.py

 # Copyright 2014 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 256 matching lines @@
     if section != 'remote "origin"':
       continue
 
     m = _GIT_CONFIG_REMOTE_URL_RE.match(line)
     if m:
       return m.group(1).strip()
 
   return None
 
 
-def _GetGitHead(path):
-  """Returns the hash of the head of the git repo in |path|. Raises an IOError
-  if |path| doesn't exist or is not a git repo.
+def _GetGitHead(repo):
+  """Returns the hash of the head of the git repo local checkout.
+
+  Raises:
+    IOError: if repo's checkout directory doesn't exist or not a git repository.
   """
-  return open(os.path.join(path, '.git', 'HEAD'), 'rb').read().strip()
+  with open(os.path.join(repo.checkout_dir, '.git', 'HEAD'), 'rb') as head:
+    return head.read().strip()
+
+
+def _GetGitFetchHead(repo):
+  """Returns the hash of the latest fetched revision.
+
+  Raises:
+    IOError: if repo's checkout directory doesn't exist or not a git repository.
+    KeyError: if the fetched head of the remote repository is not found in the
+      local checkout.
+  """
+  path = os.path.join(repo.checkout_dir, '.git', 'FETCH_HEAD')
+  with open(path, 'rb') as heads_file:
+    for line in heads_file.readlines():
+      if not line.strip():
+        continue
+      head, repo_url = line.strip().split()
+      if repo_url == repo.repository:
+        return head
+  raise KeyError('Did not find fetched head for %s in %s' %
+                 (repo.repository, path))
 
 
 def _NormalizeGitPath(path):
   """Given a |path| in a GIT repository (relative to its root), normalizes it so
   it will match only that exact path in a sparse checkout.
   """
   path = path.strip()
   if not path.startswith('/'):
     path = '/' + path
   if not path.endswith('/'):
@@ skipping 91 matching lines @@
       with open(path, 'wb') as io:
         io.write(contents)
 
 
 def _UpdateCheckout(path, repo, dry_run):
   """Updates a GIT checkout in |path| by pulling down a specific revision
   from it, as configured by RepoOptions |repo|. Only actually runs if
   |dry_run| is False.
   """
   try:
-    # Try a checkout first. If this fails then we'll actually need to fetch
-    # the revision.
-    _LOGGER.info('Trying to checkout revision %s.', repo.revision)
-    _Shell('git', 'checkout', repo.revision, cwd=path,
-          dry_run=dry_run)
-    return
+    # If the repo has a revision specified, try a checkout first. If this fails
+    # then we'll actually need to fetch.
+    if _GIT_SHA1_RE.match(repo.revision):
+      _LOGGER.info('Trying to checkout revision %s.', repo.revision)
+      _Shell('git', 'checkout', repo.revision, cwd=path,
+            dry_run=dry_run)
+      return
   except RuntimeError:
     pass
 
   # Fetch the revision and then check it out. Let output go to screen rather
   # than be buffered.
-  _LOGGER.info('Fetching and checking out revision %s.', repo.revision)
+  _LOGGER.info('Fetching revision %s.', repo.revision)
   _Shell('git', 'fetch', '--depth=1', 'origin', repo.revision,
          cwd=path, dry_run=dry_run, stdout=None, stderr=None)
-  _Shell('git', 'checkout', repo.revision, cwd=path,
+  new_rev = _GetGitFetchHead(repo) if repo.revision == 'HEAD' else repo.revision
+  _LOGGER.info('Checking out revision %s.', new_rev)
+  _Shell('git', 'checkout', new_rev, cwd=path,
          dry_run=dry_run, stdout=None, stderr=None)
 
 
 # Used by _GetJunctionInfo to extract information about junctions.
 _DIR_JUNCTION_RE = re.compile(r'^.*<JUNCTION>\s+(.+)\s+\[(.+)\]$')
 
 
 # TODO(chrisha): This is ugly, and there has to be a better way!
 def _GetJunctionInfo(junction):
   """Returns the target of a junction, if it exists, None otherwise."""
@@ skipping 90 matching lines @@
     if not options.force and _IsGitCheckoutRoot(repo.checkout_dir):
       # Get the repo origin.
       repo_url = _GetGitOrigin(repo.checkout_dir)
       if (repo_url == repo.repository and
           _HasValidSparseCheckoutConfig(repo)):
         _LOGGER.debug('Checkout is for correct repository and subdirectory.')
         keep_cache_dir = True
         create_checkout = False
 
         # Get the checked out revision.
-        revhash = _GetGitHead(repo.checkout_dir)
+        revhash = _GetGitHead(repo)
         if revhash == repo.revision:
           _LOGGER.debug('Checkout is already up to date.')
           update_checkout = False
 
     if not keep_cache_dir:
       # The old checkout directory is renamed and erased in a separate thread
       # so that the new checkout can start immediately.
       _LOGGER.info('Erasing stale checkout directory: %s', repo.checkout_dir)
 
       # Any existing junctions to this repo must be removed otherwise the
@@ skipping 389 matching lines @@
       continue
     if not checkout_dirs[repo.checkout_dir] and not options.force:
       continue
     _RecurseRepository(options, repo)
 
   return
 
 
 if __name__ == '__main__':
   main()