script/helpers.py

   1 import sys
   2 import os
   3 from os import path
   4 import types
   5 from subprocess import Popen, PIPE, check_call
   6
   7 def run_command(args):
   8     # interpret a string as a whitespace-separated list of executable+arguments
   9     if isinstance(args, (str, bytes)):
  10         args = args.split()
  11     t = Popen(args, stdout=PIPE)
  12     stdout = t.communicate()[0]
  13     if t.returncode != 0:
  14         raise OSError("Call %s failed" % str(args))
  15     return stdout
  16
  17 class GitWrapper(object):
  18     def __init__(self):
  19         self.shallow = False
  20         self.supports_nofetch = True
  21         v = run_command('git --version')
  22         prefix = b'git version '
  23         def error():
  24             sys.stderr.write('Cannot parse "git --version" output, '
  25                              'assuming new version\n')
  26         if not v.startswith(prefix):
  27             error()
  28             return
  29         v = v[len(prefix):]
  30         try:
  31             v = [int(n) for n in v.split(b'.')[:3]]
  32         except:
  33             error()
  34             return
  35         if v < [1, 6, 2]:
  36             self.supports_nofetch = False
  37
  38     def submodule_clone(self, name):
  39         if self.shallow:
  40             # Use a depth greater than 1 for shallow clones to reduce the
  41             # chance that required submodule versions are not fetched when
  42             # all branch heads in the corresponding repo have moved ahead.
  43             shallow_args = ['--depth', '100']
  44         else:
  45             shallow_args = []
  46         if self.supports_nofetch:
  47             nofetch_args = ['--no-fetch']
  48         else:
  49             nofetch_args = []
  50         if path.exists(path.join(name, '.git')):
  51             # If the submodule already exists just try to update it
  52             check_call('git submodule sync'.split()+[name])
  53             check_call('git submodule update'.split()+[name])
  54         else:
  55             # Do things manually instead of using "git submodule update --init",
  56             # because git's sucky submodule support has no way of giving
  57             # options to the "git clone" command that would be needed for
  58             # shallow clones.
  59             repo_addr = run_command('git config --get submodule.%s.url'
  60                                     % name).strip()
  61             # old git versions fail to clone over an empty directory
  62             try:
  63                 os.rmdir(name)
  64             except:
  65                 # Don't fail if it already doesn't exist - having other
  66                 # failure cases continue and fail later is OK.
  67                 pass
  68             check_call('git clone'.split() + shallow_args + [repo_addr, name])
  69             check_call('git submodule update'.split() + nofetch_args + [name])
  70
  71     def get_config(self):
  72         output = run_command('git config --null --list')
  73         result = {}
  74         for line in output.split(bytes([0])):
  75             if not line:
  76                 continue
  77             name, value = line.split(b'\n', 1)
  78             result[name] = value
  79         return result
  80
  81     def get_submodules(self):
  82         output = run_command('git ls-files --stage')
  83         result = []
  84         for line in output.splitlines():
  85             mode, sha, stage, path = line.split(None, 3)
  86             if mode != b'160000':
  87                 continue
  88             result.append(path)
  89         return result
  90
  91     def foreach_submodule(self, func, recurse=True):
  92         for module in self.get_submodules():
  93             if path.exists(path.join(module, b'.git')):
  94                 os.chdir(module)
  95                 func()
  96                 if recurse:
  97                     self.foreach_submodule(func)
  98                 os.chdir('..')
  99
 100     def foreach_module(self, func):
 101         func()
 102         self.foreach_submodule(func)
 103
 104
 105 def parse_configfile(filename):
 106     if not path.exists(filename):
 107         return []
 108     args = []
 109     f = open(filename, 'rb')
 110     for line in f:
 111         line = line.strip()
 112         if not line or line.startswith(b'#'):
 113             continue
 114         args.append(line)
 115     f.close()
 116     return args