Generalize patch_project to patch root conversion.

recipe_modules/gclient/api.py

 # Copyright 2013 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.
 
 from recipe_engine import recipe_api
 
 
 class RevisionResolver(object):
   """Resolves the revision based on build properties."""
 
@@ skipping 130 matching lines @@
   def config_to_pythonish(cfg):
     return jsonish_to_python(cfg.as_jsonish(), True)
 
   def resolve_revision(self, revision):
     if hasattr(revision, 'resolve'):
       return revision.resolve(self.m.properties)
     return revision
 
   def sync(self, cfg, with_branch_heads=False, **kwargs):
     revisions = []
+    self.set_patch_project_revision(self.m.properties.get('patch_project'), cfg)
     for i, s in enumerate(cfg.solutions):
       if s.safesync_url:  # prefer safesync_url in gclient mode
         continue
       if i == 0 and s.revision is None:
         s.revision = RevisionFallbackChain()
 
       if s.revision is not None and s.revision != '':
         fixed_revision = self.resolve_revision(s.revision)
         if fixed_revision:
           revisions.extend(['--revision', '%s@%s' % (s.name, fixed_revision)])
@@ skipping 168 matching lines @@
           for (path, dir, files) in os.walk(build_path):
             for cur_file in files:
               if cur_file.endswith('index.lock'):
                 path_to_file = os.path.join(path, cur_file)
                 print 'deleting %s' % path_to_file
                 os.remove(path_to_file)
       """,
       args=[self.m.path['slave_build']],
       infra_step=True,
     )
+
+  def calculate_patch_root(self, patch_project, gclient_config=None):
+    """Returns path where a patch should be applied to based patch_project.
+
+    Maps "patch_project" to a path of directories relative to checkout's root,
+    which describe where to place the patch.
+
+    For now, considers only first solution (c.solutions[0]), but in theory can
+    be extended to all of them.
+
+    See patch_projects solution config property.
+
+    Returns:
+      Relative path, including solution's root.
+      If patch_project is not given or not recognized, it'll be just first
+      solution root.
+    """
+    cfg = gclient_config or self.c
+    root, _ = cfg.patch_projects.get(patch_project, ('', ''))
+    if root:
+      # Note, that c.patch_projects contains patch roots as
+      # slash(/)-separated path, which are roots of the respective project repos
+      # and include actual solution name in them.
+      return self.m.path.join(*root.split('/'))
+    # Default case - assume patch is for first solution, as this is what most
+    # projects rely on.
+    return cfg.solutions[0].name
+
+  def set_patch_project_revision(self, patch_project, gclient_config=None):
+    """Updates config revision corresponding to patch_project.
+
+    Useful for bot_update only, as this is the only consumer of gclient's config
+    revision map. This doesn't overwrite the revision if it was already set.
+    """
+    assert patch_project is None or isinstance(patch_project, basestring)
+    cfg = gclient_config or self.c
+    path, revision = cfg.patch_projects.get(patch_project, (None, None))
+    if path and revision and path not in cfg.revisions:
+      cfg.revisions[path] = revision