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          str = f.read() 
 79      return load_roshlet_str(str, plugin_context, dependencies, filename=filename) 
 80   
 81 -def load_roshlet_str(str_, plugin_context, dependencies, filename="input"): 
 82      """ 
 83      @param str_: roshlet code 
 84      @type  str_: str 
 85      @param plugin_context: context for loading plugins that roshlet depends on 
 86      @type  plugin_context: [str] 
 87      @param dependencies: names of plugins that roshlet depends on 
 88      @type  dependencies: [str] 
 89      """ 
 90      globals_ = create_globals(plugin_context, dependencies) 
 91      try: 
 92          c = compile(str_, filename, 'exec') 
 93      except SyntaxError, e: 
 94          raise ROSHException("roshlet [%s] has syntax errors: \n%s"%(filename, e)) 
 95      except TypeError, e: 
 96          raise ROSHException("roshlet [%s] source contains null bytes: \n%s"%(filename, e)) 
 97   
 98      return c, globals_ 
 99       
100 -def exec_roshlet(compiled, globals_): 
101      exec compiled in globals_ 
102   
103 -def find_roshlet(package, type_): 
104      """ 
105      @raise roslib.packages.InvalidROSPkgException: If package does not exist 
106      @raise IOError: If roshlet cannot be located 
107      """ 
108      script_candidates = roslib.packages.find_resource(package, type_) 
109      if not script_candidates: 
110          raise IOError("cannot find roshlet [%s] in package [%s]"%(type_, package)) 
111      # - for now, assume it's the first match 
112      return script_candidates[0] 
113       
114  # TODO: possibly consider executing roshlets at a particular rate 
115 -def standalone(name, script, plugins): 
116      """ 
117      Execute roshlet standalone. This method blocks until roshlet exits. 
118   
119      @param name: roshlet name 
120      @type  name: str 
121      @param package: roshlet package 
122      @type  package: str 
123      @param type_: roshlet type 
124      @type  type_: str 
125      @param plugins: list of roshlet plugins to load for roshlet 
126      @type  plugins: [str] 
127      @raise roslib.packages.InvalidROSPkgException: If package does not exist 
128      @raise IOError: If roshlet cannot be located 
129      """ 
130      # clean plugin list 
131      plugins = [p for p in plugins if p] 
132   
133      # load rosh symbols 
134      rosh.rosh_init() 
135   
136      # Load roshlet and execute blocking in this thread 
137      pc = rosh.get_default_plugin_context() 
138      args = rosh.impl.roshlets.load_roshlet(script, pc, plugins) 
139      rosh.impl.roshlets.exec_roshlet(*args) 
140