build/util/lib/common/util.py

   1 # Copyright 2013 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 """Generic utilities for all python scripts."""
   6
   7 import atexit
   8 import httplib
   9 import os
  10 import signal
  11 import stat
  12 import subprocess
  13 import sys
  14 import tempfile
  15 import urlparse
  16
  17
  18 def GetPlatformName():
  19   """Return a string to be used in paths for the platform."""
  20   if IsWindows():
  21     return 'win'
  22   if IsMac():
  23     return 'mac'
  24   if IsLinux():
  25     return 'linux'
  26   raise NotImplementedError('Unknown platform "%s".' % sys.platform)
  27
  28
  29 def IsWindows():
  30   return sys.platform == 'cygwin' or sys.platform.startswith('win')
  31
  32
  33 def IsLinux():
  34   return sys.platform.startswith('linux')
  35
  36
  37 def IsMac():
  38   return sys.platform.startswith('darwin')
  39
  40
  41 def _DeleteDir(path):
  42   """Deletes a directory recursively, which must exist."""
  43   # Don't use shutil.rmtree because it can't delete read-only files on Win.
  44   for root, dirs, files in os.walk(path, topdown=False):
  45     for name in files:
  46       filename = os.path.join(root, name)
  47       os.chmod(filename, stat.S_IWRITE)
  48       os.remove(filename)
  49     for name in dirs:
  50       os.rmdir(os.path.join(root, name))
  51   os.rmdir(path)
  52
  53
  54 def Delete(path):
  55   """Deletes the given file or directory (recursively), which must exist."""
  56   if os.path.isdir(path):
  57     _DeleteDir(path)
  58   else:
  59     os.remove(path)
  60
  61
  62 def MaybeDelete(path):
  63   """Deletes the given file or directory (recurisvely), if it exists."""
  64   if os.path.exists(path):
  65     Delete(path)
  66
  67
  68 def MakeTempDir(parent_dir=None):
  69   """Creates a temporary directory and returns an absolute path to it.
  70
  71   The temporary directory is automatically deleted when the python interpreter
  72   exits normally.
  73
  74   Args:
  75     parent_dir: the directory to create the temp dir in. If None, the system
  76                 temp dir is used.
  77
  78   Returns:
  79     The absolute path to the temporary directory.
  80   """
  81   path = tempfile.mkdtemp(dir=parent_dir)
  82   atexit.register(MaybeDelete, path)
  83   return path
  84
  85
  86 def Unzip(zip_path, output_dir):
  87   """Unzips the given zip file using a system installed unzip tool.
  88
  89   Args:
  90     zip_path: zip file to unzip.
  91     output_dir: directory to unzip the contents of the zip file. The directory
  92                 must exist.
  93
  94   Raises:
  95     RuntimeError if the unzip operation fails.
  96   """
  97   if IsWindows():
  98     unzip_cmd = ['C:\\Program Files\\7-Zip\\7z.exe', 'x', '-y']
  99   else:
 100     unzip_cmd = ['unzip', '-o']
 101   unzip_cmd += [zip_path]
 102   if RunCommand(unzip_cmd, output_dir) != 0:
 103     raise RuntimeError('Unable to unzip %s to %s' % (zip_path, output_dir))
 104
 105
 106 def Kill(pid):
 107   """Terminate the given pid."""
 108   if IsWindows():
 109     subprocess.call(['taskkill.exe', '/T', '/F', '/PID', str(pid)])
 110   else:
 111     os.kill(pid, signal.SIGTERM)
 112
 113
 114 def RunCommand(cmd, cwd=None):
 115   """Runs the given command and returns the exit code.
 116
 117   Args:
 118     cmd: list of command arguments.
 119     cwd: working directory to execute the command, or None if the current
 120          working directory should be used.
 121
 122   Returns:
 123     The exit code of the command.
 124   """
 125   process = subprocess.Popen(cmd, cwd=cwd)
 126   process.wait()
 127   return process.returncode
 128
 129
 130 def DoesUrlExist(url):
 131   """Determines whether a resource exists at the given URL.
 132
 133   Args:
 134     url: URL to be verified.
 135
 136   Returns:
 137     True if url exists, otherwise False.
 138   """
 139   parsed = urlparse.urlparse(url)
 140   try:
 141     conn = httplib.HTTPConnection(parsed.netloc)
 142     conn.request('HEAD', parsed.path)
 143     response = conn.getresponse()
 144   except (socket.gaierror, socket.error):
 145     return False
 146   finally:
 147     conn.close()
 148   # Follow both permanent (301) and temporary (302) redirects.
 149   if response.status == 302 or response.status == 301:
 150     return DoesUrlExist(response.getheader('location'))
 151   return response.status == 200