Source Code for Module rosh.impl.roshlets

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 33  # Revision $Id: roshlets.py 11292 2010-09-28 01:11:36Z kwc $ 
 34   
 35  from __future__ import with_statement 
 36   
 37  import sys 
 38   
 39  import roslib.packages 
 40   
 41  import rosh 
 42  from rosh.impl.exceptions import ROSHException 
 43  import rosh.impl.ros_graph 
 44   
 45 -def create_globals(plugin_context, dependencies): 
 46      """ 
 47      Generate global symbol table for roshlet 
 48   
 49      @param plugin_context: context for loading plugins that roshlet depends on 
 50      @type  plugin_context: [str] 
 51      @param dependencies: names of plugins that roshlet depends on 
 52      @type  dependencies: [str] 
 53      """ 
 54   
 55      rosh = sys.modules['rosh'] 
 56      # TODO: need to have an __all__ table instead so as to not load in extra dependencies 
 57      globals_ = rosh.__dict__.copy() 
 58      globals_['rosh'] = rosh 
 59   
 60      # load in default symbols 
 61      # TODO: need common init routine for rosh so that this does not diverge 
 62      rosh.impl.ros_graph.load_rosh_plugin('rosh.impl.ros_graph', plugin_context, globals_) 
 63   
 64      for d in dependencies: 
 65          rosh.plugin.load_plugin(d, plugin_context, globals_) 
 66      return globals_ 
 67   
 68 -def load_roshlet(filename, plugin_context, dependencies): 
 69      """ 
 70      @param filename: name of file with roshlet code 
 71      @type  filename: str 
 72      @param plugin_context: context for loading plugins that roshlet depends on 
 73      @type  plugin_context: [str] 
 74      @param dependencies: names of plugins that roshlet depends on 
 75      @type  dependencies: [str] 
 76      """ 
 77      with open(filename) as f: 
 78          contents = f.read() 
 79      if contents.startswith("#|\nexec"): 
 80          contents = contents[contents.find('|#')+2:] 
 81      return load_roshlet_str(contents, plugin_context, dependencies, filename=filename) 
 82   
 83 -def load_roshlet_str(str_, plugin_context, dependencies, filename="input"): 
 84      """ 
 85      @param str_: roshlet code 
 86      @type  str_: str 
 87      @param plugin_context: context for loading plugins that roshlet depends on 
 88      @type  plugin_context: [str] 
 89      @param dependencies: names of plugins that roshlet depends on 
 90      @type  dependencies: [str] 
 91      """ 
 92      globals_ = create_globals(plugin_context, dependencies) 
 93      try: 
 94          c = compile(str_, filename, 'exec') 
 95      except SyntaxError, e: 
 96          raise ROSHException("roshlet [%s] has syntax errors: \n%s"%(filename, e)) 
 97      except TypeError, e: 
 98          raise ROSHException("roshlet [%s] source contains null bytes: \n%s"%(filename, e)) 
 99   
100      return c, globals_ 
101       
102 -def exec_roshlet(compiled, globals_): 
103      exec compiled in globals_ 
104   
105 -def find_roshlet(package, type_): 
106      """ 
107      @raise roslib.packages.InvalidROSPkgException: If package does not exist 
108      @raise IOError: If roshlet cannot be located 
109      """ 
110      script_candidates = roslib.packages.find_resource(package, type_) 
111      if not script_candidates: 
112          raise IOError("cannot find roshlet [%s] in package [%s]"%(type_, package)) 
113      # - for now, assume it's the first match 
114      return script_candidates[0] 
115       
116  # TODO: possibly consider executing roshlets at a particular rate 
117 -def standalone(name, script, plugins): 
118      """ 
119      Execute roshlet standalone. This method blocks until roshlet exits. 
120   
121      @param name: roshlet name 
122      @type  name: str 
123      @param package: roshlet package 
124      @type  package: str 
125      @param type_: roshlet type 
126      @type  type_: str 
127      @param plugins: list of roshlet plugins to load for roshlet 
128      @type  plugins: [str] 
129      @raise roslib.packages.InvalidROSPkgException: If package does not exist 
130      @raise IOError: If roshlet cannot be located 
131      """ 
132      # clean plugin list 
133      plugins = [p for p in plugins if p] 
134   
135      # load rosh symbols 
136      rosh.rosh_init() 
137   
138      # Load roshlet and execute blocking in this thread 
139      pc = rosh.get_default_plugin_context() 
140      args = rosh.impl.roshlets.load_roshlet(script, pc, plugins) 
141      rosh.impl.roshlets.exec_roshlet(*args) 
142