Improve trace_inputs.py to output a format easy to convert to gypi.

tools/isolate/isolate.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.
 
 """Does one of the following depending on the --mode argument:
   check     Verifies all the inputs exist, touches the file specified with
             --result and exits.
   hashtable Puts a manifest file and hard links each of the inputs into the
             output directory.
@@ skipping 86 matching lines @@
   if not cmd:
     # Note that it is exactly the reverse of relative_cwd.
     cmd = [os.path.join(os.path.relpath(indir, cwd), infiles[0])]
   if cmd[0].endswith('.py'):
     cmd.insert(0, sys.executable)
 
   # Only hashtable mode really needs the sha-1.
   dictfiles = tree_creator.process_inputs(
       indir, infiles, mode == 'hashtable', read_only)
 
-  if not outdir:
-    outdir = os.path.dirname(resultfile)
-  result = mode_fn(outdir, indir, dictfiles, read_only, cmd, relative_cwd)
+  result = mode_fn(
+      outdir, indir, dictfiles, read_only, cmd, relative_cwd,
+      os.path.dirname(resultfile))
 
   if result == 0:
     # Saves the resulting file.
     out = {
       'command': cmd,
       'relative_cwd': relative_cwd,
       'files': dictfiles,
     }
     with open(resultfile, 'wb') as f:
       json.dump(out, f, indent=2, sort_keys=True)
   return result
 
 
-def MODEcheck(outdir, indir, dictfiles, read_only, cmd, relative_cwd):
+def MODEcheck(
+    outdir, indir, dictfiles, read_only, cmd, relative_cwd, result_path):
   """No-op."""
   return 0
 
 
-def MODEhashtable(outdir, indir, dictfiles, read_only, cmd, relative_cwd):
+def MODEhashtable(
+    outdir, indir, dictfiles, read_only, cmd, relative_cwd, result_path):
   """Ignores read_only, cmd and relative_cwd."""
+  outdir = outdir or result_path
   for relfile, properties in dictfiles.iteritems():
     infile = os.path.join(indir, relfile)
     outfile = os.path.join(outdir, properties['sha-1'])
     if os.path.isfile(outfile):
       # Just do a quick check that the file size matches.
       if os.stat(infile).st_size == os.stat(outfile).st_size:
         continue
       # Otherwise, an exception will be raised.
     tree_creator.link_file(outfile, infile, tree_creator.HARDLINK)
   return 0
 
 
-def MODEremap(outdir, indir, dictfiles, read_only, cmd, relative_cwd):
-  """Ignores cmd and relative_cwd."""
+def MODEremap(
+    outdir, indir, dictfiles, read_only, cmd, relative_cwd, result_path):
+  """Ignores outdir, cmd and relative_cwd."""
   if not outdir:
     outdir = tempfile.mkdtemp(prefix='isolate')
+  print 'Remapping into %s' % outdir
+  if len(os.listdir(outdir)):
+    print 'Can\'t remap in a non-empty directory'
+    return 1
   tree_creator.recreate_tree(
       outdir, indir, dictfiles.keys(), tree_creator.HARDLINK)
   if read_only:
     tree_creator.make_writable(outdir, True)
   return 0
 
 
-def MODErun(outdir, indir, dictfiles, read_only, cmd, relative_cwd):
-  """Ignores outdir and always uses a temporary directory."""
-  outdir = None
+def MODErun(
+    outdir, indir, dictfiles, read_only, cmd, relative_cwd, result_path):
+  """Always uses a temporary directory."""
   try:
     outdir = tempfile.mkdtemp(prefix='isolate')
     tree_creator.recreate_tree(
         outdir, indir, dictfiles.keys(), tree_creator.HARDLINK)
     cwd = os.path.join(outdir, relative_cwd)
     if not os.path.isdir(cwd):
       os.makedirs(cwd)
     if read_only:
       tree_creator.make_writable(outdir, True)
 
@@ skipping 76 matching lines @@
         options.mode,
         options.read_only,
         cmd)
   except tree_creator.MappingError, e:
     print >> sys.stderr, str(e)
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())