Source Code for Module zeroinstall.helpers

  1  """ 
  2  Convenience routines for performing common operations. 
  3  @since: 0.28 
  4  """ 
  5   
  6  # Copyright (C) 2009, Thomas Leonard 
  7  # See the README file for details, or visit http://0install.net. 
  8   
  9  import os, sys, logging 
 10  from zeroinstall import support 
 11  from zeroinstall.support import tasks 
 12   
 13 -def get_selections_gui(iface_uri, gui_args, test_callback = None): 
 14          """Run the GUI to choose and download a set of implementations. 
 15          The user may ask the GUI to submit a bug report about the program. In that case, 
 16          the GUI may ask us to test it. test_callback is called in that case with the implementations 
 17          to be tested; the callback will typically call L{zeroinstall.injector.run.test_selections} and return the result of that. 
 18          @param iface_uri: the required program, or None to show just the preferences dialog 
 19          @type iface_uri: str 
 20          @param gui_args: any additional arguments for the GUI itself 
 21          @type gui_args: [str] 
 22          @param test_callback: function to use to try running the program 
 23          @type test_callback: L{zeroinstall.injector.selections.Selections} -> str 
 24          @return: the selected implementations 
 25          @rtype: L{zeroinstall.injector.selections.Selections} 
 26          @since: 0.28 
 27          """ 
 28          from zeroinstall.injector import selections, qdom 
 29          from StringIO import StringIO 
 30   
 31          from os.path import join, dirname 
 32          gui_exe = join(dirname(__file__), '0launch-gui', '0launch-gui') 
 33   
 34          import socket 
 35          cli, gui = socket.socketpair() 
 36   
 37          try: 
 38                  child = os.fork() 
 39                  if child == 0: 
 40                          # We are the child (GUI) 
 41                          try: 
 42                                  try: 
 43                                          cli.close() 
 44                                          # We used to use pipes to support Python2.3... 
 45                                          os.dup2(gui.fileno(), 1) 
 46                                          os.dup2(gui.fileno(), 0) 
 47                                          if iface_uri is not None: 
 48                                                  gui_args = gui_args + ['--', iface_uri] 
 49                                          os.execvp(sys.executable, [sys.executable, gui_exe] + gui_args) 
 50                                  except: 
 51                                          import traceback 
 52                                          traceback.print_exc(file = sys.stderr) 
 53                          finally: 
 54                                  sys.stderr.flush() 
 55                                  os._exit(1) 
 56                  # We are the parent (CLI) 
 57                  gui.close() 
 58                  gui = None 
 59   
 60                  while True: 
 61                          logging.info("Waiting for selections from GUI...") 
 62   
 63                          reply = support.read_bytes(cli.fileno(), len('Length:') + 9, null_ok = True) 
 64                          if reply: 
 65                                  if not reply.startswith('Length:'): 
 66                                          raise Exception("Expected Length:, but got %s" % repr(reply)) 
 67                                  xml = support.read_bytes(cli.fileno(), int(reply.split(':', 1)[1], 16)) 
 68   
 69                                  dom = qdom.parse(StringIO(xml)) 
 70                                  sels = selections.Selections(dom) 
 71   
 72                                  if dom.getAttribute('run-test'): 
 73                                          logging.info("Testing program, as requested by GUI...") 
 74                                          if test_callback is None: 
 75                                                  output = "Can't test: no test_callback was passed to get_selections_gui()\n" 
 76                                          else: 
 77                                                  output = test_callback(sels) 
 78                                          logging.info("Sending results to GUI...") 
 79                                          output = ('Length:%8x\n' % len(output)) + output 
 80                                          logging.debug("Sending: %s", repr(output)) 
 81                                          while output: 
 82                                                  sent = cli.send(output) 
 83                                                  output = output[sent:] 
 84                                          continue 
 85                          else: 
 86                                  sels = None 
 87   
 88                          pid, status = os.waitpid(child, 0) 
 89                          assert pid == child 
 90                          if status == 1 << 8: 
 91                                  logging.info("User cancelled the GUI; aborting") 
 92                                  return None             # Aborted 
 93                          if status != 0: 
 94                                  raise Exception("Error from GUI: code = %d" % status) 
 95                          break 
 96          finally: 
 97                  for sock in [cli, gui]: 
 98                          if sock is not None: sock.close() 
 99           
100          return sels 
101   
102 -def ensure_cached(uri, command = 'run', config = None): 
103          """Ensure that an implementation of uri is cached. 
104          If not, it downloads one. It uses the GUI if a display is 
105          available, or the console otherwise. 
106          @param uri: the required interface 
107          @type uri: str 
108          @return: the selected implementations, or None if the user cancelled 
109          @rtype: L{zeroinstall.injector.selections.Selections} 
110          """ 
111          from zeroinstall.injector.driver import Driver 
112   
113          if config is None: 
114                  from zeroinstall.injector.config import load_config 
115                  config = load_config() 
116   
117          from zeroinstall.injector.requirements import Requirements 
118          requirements = Requirements(uri) 
119          requirements.command = command 
120   
121          d = Driver(config, requirements) 
122   
123          if d.need_download() or not d.solver.ready: 
124                  if os.environ.get('DISPLAY', None): 
125                          return get_selections_gui(uri, ['--command', command]) 
126                  else: 
127                          done = d.solve_and_download_impls() 
128                          tasks.wait_for_blocker(done) 
129   
130          return d.solver.selections 
131