Add script to run a test in a separate read-only directory.

isolate/tree_creator.py

+# 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 tree of hardlinks."""
+
+import logging
+import os
+import shutil
+import sys
+
+import find_depot_tools  # pylint: disable=W0611
+import gclient_utils
+
+
+# Types of action accepted by recreate_tree().
+DRY_RUN, HARDLINK, SYMLINK, COPY = range(5)[1:]
+
+
+def CreateHardLink(src, dst):
+  """Add support for os.link() on Windows."""
+  import ctypes
+  if not ctypes.windll.kernel32.CreateHardLinkW(unicode(dst), unicode(src), 0):
+    raise OSError()
+
+
+class Foo(OSError):
+  """Failed to recreate the tree."""
+  pass
+
+
+def recreate_tree(outdir, indir, infiles, action, blacklist):
+  """Creates a new tree with only the input files in it."""
+  assert action in (DRY_RUN, HARDLINK, SYMLINK, COPY)
+  indir = os.path.normpath(indir)
+  outdir = os.path.normpath(outdir)
+  logging.info('%s -> %s' % (indir, outdir))
+  if not os.path.isdir(indir):
+    raise Foo('%s is not a directory' % indir)
+  # Do not call abspath until it was verified the directory exists.
+  indir = os.path.abspath(indir)
+  if os.path.isdir(outdir):
+    logging.warn('Deleting %s' % outdir)
+    if action != DRY_RUN:
+      gclient_utils.RemoveDirectory(outdir)
+  if action != DRY_RUN:
+    logging.info ('Creating %s' % outdir)
+    os.makedirs(outdir)
+    # Do not call abspath until the directory exists.
+    outdir = os.path.abspath(outdir)
+    logging.info ('Created %s' % outdir)
+
+  def process(inf, outf):
+    inf = os.path.normpath(inf)
+    outf = os.path.normpath(outf)
+    if action == DRY_RUN:
+      print outf
+    else:
+      logging.debug('%s -> %s' % (inf, outf))
+      if not os.path.isfile(inf):
+        raise Foo('%s doesn\'t exist' % inf)
+      if os.path.isfile(outf):
+        raise Foo('%s already exist' % outf)
+      if action == COPY:
+        shutil.copy(inf, outf)
+      elif action == SYMLINK:
+        os.symlink(inf, outf)
+      try:
+        if action == HARDLINK:
+          if sys.platform == 'win32':
+            CreateHardLink(inf, outf)
+          else:
+            os.link(inf, outf)
+      except OSError:
+        # Probably a different file system.
+        os.symlink(inf, outf)
+
+      # Make the file read-only.
+      # TODO(maruel): Implement DACL modification on Windows.
+      mode = os.stat(inf).st_mode
+      mode = mode & 0500
+      if hasattr(os, 'lchmod'):
+        # Module 'os' has no 'lchmod' member
+        # pylint: disable=E1101
+        os.lchmod(outf, mode)
+      else:
+        os.chmod(outf, mode)
+
+  for relfile in infiles:
+    infile = os.path.normpath(os.path.join(indir, relfile))
+    logging.debug(infile)
+    if not infile.startswith(indir):
+      raise Foo('Can\'t map file %s outside %s' % (infile, indir))
+    if os.path.isdir(infile):
+      # Process recursively.
+      for dirpath, dirnames, filenames in os.walk(infile):
+        insubdir = os.path.normpath(os.path.join(infile, dirpath))
+        outsubdir = os.path.normpath(
+            os.path.join(outdir, insubdir[len(indir) + 1:]))
+        for filename in filenames:
+          insubfile = os.path.normpath(os.path.join(infile, dirpath, filename))
+          outsubfile = os.path.normpath(os.path.join(outsubdir, filename))
+          if blacklist and blacklist(outsubfile):
+            continue
+          if not os.path.isdir(outsubdir):
+            os.makedirs(outsubdir)
+          process(insubfile, outsubfile)
+        for index, dirname in enumerate(dirnames):
+          if blacklist(os.path.normpath(os.path.join(outdir, dirname))):
+            del dirnames[index]
+    else:
+      # TODO(maruel): Is that secure?
+      outsubfile = os.path.normpath(os.path.join(outdir, relfile))
+      if blacklist and blacklist(outsubfile):
+        continue
+      outsubdir = os.path.dirname(outsubfile)
+      if not os.path.isdir(outsubdir):
+        os.makedirs(outsubdir)
+      process(infile, outsubfile)
+
+  # Then mark all the directories as read-only to inhibit file creation.
+  for dirpath, _, _ in os.walk(outdir):
+    # TODO(maruel): Implement DACL modification on Windows.
+    os.chmod(os.path.join(outdir, dirpath), 0500)