Teach ninja to handle output directories outside the source dir.

pylib/gyp/common.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from __future__ import with_statement
 
 import errno
 import filecmp
 import os.path
 import re
@@ skipping 109 matching lines @@
     fully_qualified = fully_qualified + '#' + toolset
   return fully_qualified
 
 
 @memoize
 def RelativePath(path, relative_to):
   # Assuming both |path| and |relative_to| are relative to the current
   # directory, returns a relative path that identifies path relative to
   # relative_to.
 
   # Convert to absolute (and therefore normalized paths).

[Nico, 2012/12/21 22:52:08]

Is the comment now out of date?

-  path = os.path.abspath(path)
-  relative_to = os.path.abspath(relative_to)
+  path = os.path.realpath(path)
+  relative_to = os.path.realpath(relative_to)
 
   # Split the paths into components.
   path_split = path.split(os.path.sep)
   relative_to_split = relative_to.split(os.path.sep)
 
   # Determine how much of the prefix the two paths share.
   prefix_len = len(os.path.commonprefix([path_split, relative_to_split]))
 
   # Put enough ".." components to back up out of relative_to to the common
   # prefix, and then append the part of path_split after the common prefix.
   relative_split = [os.path.pardir] * (len(relative_to_split) - prefix_len) + \
                    path_split[prefix_len:]
 
   if len(relative_split) == 0:
     # The paths were the same.
     return ''
 
   # Turn it back into a string and we're done.
   return os.path.join(*relative_split)
 
 
+@memoize
+def InvertRelativePath(path, toplevel_dir=None):
+  """Given a path like foo/bar that is relative to toplevel_dir, return
+  the inverse relative path back to the toplevel_dir.
+
+  E.g. os.path.normpath(os.path.join(path, InvertRelativePath(path)))
+  should always produce the empty string, unless the path contains symlinks.
+  """
+  if not path:
+    return path
+  toplevel_dir = '.' if toplevel_dir is None else toplevel_dir
+  return RelativePath(toplevel_dir, os.path.join(toplevel_dir, path))
+
+
 def FixIfRelativePath(path, relative_to):
   # Like RelativePath but returns |path| unchanged if it is absolute.
   if os.path.isabs(path):
     return path
   return RelativePath(path, relative_to)
 
 
 def UnrelativePath(path, relative_to):
   # Assuming that |relative_to| is relative to the current directory, and |path|
   # is a path relative to the dirname of |relative_to|, returns a path that
@@ skipping 300 matching lines @@
       return
     visited.add(node)
     visiting.add(node)
     for neighbor in get_edges(node):
       Visit(neighbor)
     visiting.remove(node)
     ordered_nodes.insert(0, node)
   for node in sorted(graph):
     Visit(node)
   return ordered_nodes