native_client_sdk/src/build_tools/sdk_tools/sdk_update_common.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Utility functions for sdk_update.py and sdk_update_main.py."""
   6
   7 import errno
   8 import logging
   9 import os
  10 import shutil
  11 import subprocess
  12 import sys
  13 import time
  14
  15
  16 class Error(Exception):
  17   """Generic error/exception for sdk_update module"""
  18   pass
  19
  20
  21 def MakeDirs(directory):
  22   if not os.path.exists(directory):
  23     logging.info('Making directory %s' % (directory,))
  24     os.makedirs(directory)
  25
  26
  27 def RemoveDir(outdir):
  28   """Removes the given directory
  29
  30   On Unix systems, this just runs shutil.rmtree, but on Windows, this doesn't
  31   work when the directory contains junctions (as does our SDK installer).
  32   Therefore, on Windows, it runs rmdir /S /Q as a shell command.  This always
  33   does the right thing on Windows. If the directory already didn't exist,
  34   RemoveDir will return successfully without taking any action.
  35
  36   Args:
  37     outdir: The directory to delete
  38
  39   Raises:
  40     Error - If this operation fails for any reason.
  41   """
  42
  43   max_tries = 5
  44   last_exception = None
  45   for num_tries in xrange(max_tries):
  46     try:
  47       shutil.rmtree(outdir)
  48       return
  49     except OSError as e:
  50       if not os.path.exists(outdir):
  51         # The directory can't be removed because it doesn't exist.
  52         return
  53       last_exception = e
  54
  55     # On Windows this could be an issue with junctions, so try again with
  56     # rmdir.
  57     if sys.platform == 'win32':
  58       try:
  59         cmd = ['rmdir', '/S', '/Q', outdir]
  60         process = subprocess.Popen(cmd, stderr=subprocess.PIPE, shell=True)
  61         _, stderr = process.communicate()
  62         if process.returncode != 0:
  63           raise Error('\"%s\" failed with code %d. Output:\n  %s' % (
  64             ' '.join(cmd), process.returncode, stderr))
  65         return
  66         # Ignore failures, we'll just try again.
  67       except subprocess.CalledProcessError as e:
  68         # CalledProcessError has no error message, generate one.
  69         last_exception = Error('\"%s\" failed with code %d.' % (
  70           ' '.join(e.cmd), e.returncode))
  71       except Error as e:
  72         last_exception = e
  73
  74     # Didn't work, sleep and try again.
  75     time.sleep(num_tries + 1)
  76
  77   # Failed.
  78   raise Error('Unable to remove directory "%s"\n  %s' % (outdir,
  79                                                          last_exception))
  80
  81
  82 def RenameDir(srcdir, destdir):
  83   """Renames srcdir to destdir. Removes destdir before doing the
  84      rename if it already exists."""
  85
  86   max_tries = 5
  87   num_tries = 0
  88   for num_tries in xrange(max_tries):
  89     try:
  90       RemoveDir(destdir)
  91       shutil.move(srcdir, destdir)
  92       return
  93     except OSError as err:
  94       if err.errno != errno.EACCES:
  95         raise err
  96       # If we are here, we didn't exit due to raised exception, so we are
  97       # handling a Windows flaky access error.  Sleep one second and try
  98       # again.
  99       time.sleep(num_tries + 1)
 100
 101   # end of while loop -- could not RenameDir
 102   raise Error('Could not RenameDir %s => %s after %d tries.\n'
 103               'Please check that no shells or applications '
 104               'are accessing files in %s.'
 105               % (srcdir, destdir, num_tries + 1, destdir))