Jython

Update of /cvsroot/jython/jython/Lib
In directory sc8-pr-cvs1:/tmp/cvs-serv31692

Modified Files:
	javaos.py popen2.py 
Added Files:
	LazyDict.py 
Log Message:
Optimize startup by delaying javashell functions until needed

--- NEW FILE: LazyDict.py ---
from UserDict import UserDict
class LazyDict( UserDict ):
    """A lazy-populating User Dictionary.
    Lazy initialization is not thread-safe.
    """
    def __init__( self,
                  dict=None,
                  populate=None,
                  keyTransform=None ):
        """dict: starting dictionary of values
        populate: function that returns the populated dictionary
        keyTransform: function to normalize the keys (e.g., toupper/None)
        """
        UserDict.__init__( self, dict )
        self._populated = 0
        self.__populateFunc = populate or (lambda: {})
        self._keyTransform = keyTransform or (lambda key: key)

    def __populate( self ):
        if not self._populated:
            # race condition - test, populate, set
            # make sure you don't set _populated until __populateFunc completes...
            self.data = self.__populateFunc()
            self._populated = 1 

    ########## extend methods from UserDict by pre-populating
    def __repr__(self):
        self.__populate()
        return UserDict.__repr__( self )
    def __cmp__(self, dict):
        self.__populate()
        return UserDict.__cmp__( self, dict )
    def __len__(self):
        self.__populate()
        return UserDict.__len__( self )
    def __getitem__(self, key):
        self.__populate()
        return UserDict.__getitem__( self, self._keyTransform(key) )
    def __setitem__(self, key, item):
        self.__populate()
        UserDict.__setitem__( self, self._keyTransform(key), item )
    def __delitem__(self, key):
        self.__populate()
        UserDict.__delitem__( self, self._keyTransform(key) )
    def clear(self):
        self.__populate()
        UserDict.clear( self )
    def copy(self):
        self.__populate()
        return UserDict.copy( self )
    def keys(self):
        self.__populate()
        return UserDict.keys( self )
    def items(self):
        self.__populate()
        return UserDict.items( self )
    def values(self):
        self.__populate()
        return UserDict.values( self )
    def has_key(self, key):
        self.__populate()
        return UserDict.has_key( self, self._keyTransform(key) )
    def update(self, dict):
        self.__populate()
        UserDict.update( self, dict )
    def get(self, key, failobj=None):
        self.__populate()
        return UserDict.get( self, self._keyTransform(key), failobj )
    def setdefault(self, key, failobj=None):
        self.__populate()
        return UserDict.setdefault( self, self._keyTransform(key), failobj )
    def popitem(self):
        self.__populate()
        return UserDict.popitem( self )


Index: javaos.py
===================================================================
RCS file: /cvsroot/jython/jython/Lib/javaos.py,v
retrieving revision 2.18
retrieving revision 2.19
diff -C2 -d -r2.18 -r2.19
*** javaos.py	9 Apr 2003 13:51:50 -0000	2.18
--- javaos.py	18 Apr 2003 05:47:27 -0000	2.19
***************
*** 30,33 ****
--- 30,34 ----
  from java.io import File
  import javapath as path
+ from LazyDict import LazyDict
  
  error = OSError
***************
*** 101,109 ****
          File(path).setLastModified(long(times[1] * 1000.0))
  
! # provide environ, popen*, and system objects
! from javashell import environ, putenv, getenv
! from popen2 import popen, system
  
- # os versions have different return value order than popen2 functions
  def popen2(cmd, mode="t", bufsize=-1):
      import popen2
--- 102,130 ----
          File(path).setLastModified(long(times[1] * 1000.0))
  
! # Provide lazy environ, popen*, and system objects
! # Do these lazily, as most jython programs don't need them,
! # and they are very expensive to initialize
! 
! def _getEnvironment():
!     import javashell
!     return javashell._shellEnv.environment
! 
! environ = LazyDict( populate=_getEnvironment )
! putenv = environ.__setitem__
! getenv = environ.__getitem__
! 
! def system( *args, **kwargs ):
!     # allow lazy import of popen2 and javashell
!     import popen2
!     return popen2.system( *args, **kwargs )
! 
! def popen( *args, **kwargs ):
!     # allow lazy import of popen2 and javashell
!     import popen2
!     return popen2.popen( *args, **kwargs )
! 
! # os module versions of the popen# methods have different return value
! # order than popen2 functions
  
  def popen2(cmd, mode="t", bufsize=-1):
      import popen2

Index: popen2.py
===================================================================
RCS file: /cvsroot/jython/jython/Lib/popen2.py,v
retrieving revision 2.5
retrieving revision 2.6
diff -C2 -d -r2.5 -r2.6
*** popen2.py	19 Dec 2002 22:03:24 -0000	2.5
--- popen2.py	18 Apr 2003 05:47:27 -0000	2.6
***************
*** 65,69 ****
          specifies the size of the I/O buffers to/from the child process.
          """
-         import os
          self.process = shellexecute( cmd )
          self._tochild = self.process.getOutputStream()
--- 65,68 ----