zeroinstall/injector/autopolicy.py

   1 """
   2 A simple non-interactive policy.
   3
   4 This module provides a simple policy that will select, download and run a suitable set of
   5 implementations. It is not interactive. This is the policy used when you run B{0launch -c}, and
   6 is also the policy used to run the injector's GUI.
   7 """
   8
   9 # Copyright (C) 2006, Thomas Leonard
  10 # See the README file for details, or visit http://0install.net.
  11
  12 import os
  13 from logging import debug, info
  14
  15 from zeroinstall.injector import model, policy, run, handler
  16 from zeroinstall import NeedDownload
  17
  18 class AutoPolicy(policy.Policy):
  19         __slots__ = ['allow_downloads', 'download_only', 'dry_run']
  20
  21         def __init__(self, interface_uri, download_only = False, dry_run = False, src = False):
  22                 policy.Policy.__init__(self, interface_uri, handler.Handler(), src = src)
  23                 self.dry_run = dry_run
  24                 self.allow_downloads = not dry_run
  25                 self.download_only = download_only
  26                 self.dry_run = dry_run
  27
  28         def need_download(self):
  29                 """Decide whether we need to download anything (but don't do it!)
  30                 @return: true if we MUST download something (interfaces or implementations)
  31                 @rtype: bool
  32                 @postcondition: if we return False, self.stale_feeds contains any feeds which SHOULD be updated
  33                 """
  34                 old = self.allow_downloads
  35                 self.allow_downloads = False
  36                 try:
  37                         try:
  38                                 self.recalculate(fetch_stale_interfaces = False)
  39                                 debug("Recalculated: ready = %s; %d stale feeds", self.ready, len(self.stale_feeds))
  40                                 if not self.ready: return False
  41                                 self.start_downloading_impls()
  42                         except NeedDownload:
  43                                 return True
  44                         return False
  45                 finally:
  46                         self.allow_downloads = old
  47
  48         def begin_iface_download(self, interface, force = False):
  49                 if self.dry_run or not self.allow_downloads:
  50                         raise NeedDownload(interface.uri)
  51                 else:
  52                         policy.Policy.begin_iface_download(self, interface, force)
  53
  54         def start_downloading_impls(self):
  55                 for iface, impl in self.get_uncached_implementations():
  56                         debug("start_downloading_impls: for %s get %s", iface, impl)
  57                         source = self.get_best_source(impl)
  58                         if not source:
  59                                 raise model.SafeException("Implementation " + impl.id + " of "
  60                                         "interface " + iface.get_name() + " cannot be "
  61                                         "downloaded (no download locations given in "
  62                                         "interface!)")
  63                         self.begin_impl_download(impl, source)
  64
  65         def begin_archive_download(self, download_source, success_callback, force = False):
  66                 if self.dry_run or not self.allow_downloads:
  67                         raise NeedDownload(download_source.url)
  68                 return policy.Policy.begin_archive_download(self, download_source, success_callback, force = force)
  69
  70         def execute(self, prog_args, main = None, wrapper = None):
  71                 self.start_downloading_impls()
  72                 self.handler.wait_for_downloads()
  73                 if not self.download_only:
  74                         run.execute(self, prog_args, dry_run = self.dry_run, main = main, wrapper = wrapper)
  75                 else:
  76                         info("Downloads done (download-only mode)")
  77
  78         def recalculate_with_dl(self):
  79                 self.recalculate()
  80                 while self.handler.monitored_downloads:
  81                         self.handler.wait_for_downloads()
  82                         self.recalculate()
  83
  84         def download_and_execute(self, prog_args, refresh = False, main = None):
  85                 self.recalculate_with_dl()
  86                 if refresh:
  87                         self.refresh_all(False)
  88                         self.recalculate_with_dl()
  89                 if not self.ready:
  90                         raise model.SafeException("Can't find all required implementations:\n" +
  91                                 '\n'.join(["- %s -> %s" % (iface, self.implementation[iface])
  92                                            for iface  in self.implementation]))
  93                 self.execute(prog_args, main = main)