Linux library loaders: use relative path for includes (for distcc).

tools/generate_library_loader/generate_library_loader.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """
 Creates a library loader (a header and implementation file),
 which is a wrapper for dlopen or direct linking with given library.
 
 The loader makes it possible to have the same client code for both cases,
@@ skipping 144 matching lines @@
     parser.error('Missing --name parameter')
   if not options.output_cc:
     parser.error('Missing --output-cc parameter')
   if not options.output_h:
     parser.error('Missing --output-h parameter')
   if not options.header:
     parser.error('Missing --header paramater')
   if not args:
     parser.error('No function names specified')
 
-  # Make sure we are always dealing with an absolute path
+  # Make sure we are always dealing with paths relative to source tree root
   # to avoid issues caused by different relative path roots.
-  options.output_cc = os.path.abspath(options.output_cc)
-  options.output_h = os.path.abspath(options.output_h)
+  source_tree_root = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..', '..'))
+  options.output_cc = os.path.relpath(options.output_cc, source_tree_root)
+  options.output_h = os.path.relpath(options.output_h, source_tree_root)
 
   # Create a unique prefix, e.g. for header guards.
   # Stick a known string at the beginning to ensure this doesn't begin
   # with an underscore, which is reserved for the C++ implementation.
   unique_prefix = ('LIBRARY_LOADER_' +
                    re.sub(r'[\W]', '_', options.output_h).upper())
 
   member_decls = []
   member_init = []
   member_cleanup = []
@@ skipping 25 matching lines @@
   if options.link_directly == 0:
     wrapped_header_include += '#define %s_DLOPEN\n' % unique_prefix
   elif options.link_directly == 1:
     wrapped_header_include += '#define %s_DT_NEEDED\n' % unique_prefix
   else:
     parser.error('Invalid value for --link-directly. Should be 0 or 1.')
 
   # Make it easier for people to find the code generator just in case.
   # Doing it this way is more maintainable, because it's going to work
   # even if file gets moved without updating the contents.
-  generator_path = os.path.abspath(__file__)
+  generator_path = os.path.relpath(__file__, source_tree_root)
 
   header_contents = HEADER_TEMPLATE % {
     'generator_path': generator_path,
     'unique_prefix': unique_prefix,
     'wrapped_header_include': wrapped_header_include,
     'class_name': options.name,
     'member_decls': ''.join(member_decls),
   }
 
   impl_contents = IMPL_TEMPLATE % {
     'generator_path': generator_path,
     'unique_prefix': unique_prefix,
     'generated_header_name': options.output_h,
     'class_name': options.name,
     'member_init': ''.join(member_init),
     'member_cleanup': ''.join(member_cleanup),
   }
 
-  header_file = open(options.output_h, 'w')
+  header_file = open(os.path.join(source_tree_root, options.output_h), 'w')
   try:
     header_file.write(header_contents)
   finally:
     header_file.close()
 
-  impl_file = open(options.output_cc, 'w')
+  impl_file = open(os.path.join(source_tree_root, options.output_cc), 'w')
   try:
     impl_file.write(impl_contents)
   finally:
     impl_file.close()
 
   return 0
 
 if __name__ == '__main__':
   sys.exit(main())