wxPython/samples/ide/activegrid/util/cachedloader.py

   1 #----------------------------------------------------------------------------
   2 # Name:         cachedloader.py
   3 # Purpose:
   4 #
   5 # Author:       Joel Hare
   6 #
   7 # Created:      8/31/04
   8 # CVS-ID:       $Id$
   9 # Copyright:    (c) 2004-2005 ActiveGrid, Inc.
  10 # License:      wxWindows License
  11 #----------------------------------------------------------------------------
  12
  13 import copy
  14 import os.path
  15 import string
  16 import cStringIO
  17
  18 import time
  19
  20 # TODO: Instantiate the database and create a pool
  21
  22
  23 class CachedLoader(object):
  24     def __init__(self):
  25         self.cache = {}
  26         self.baseLoadDir = None
  27
  28     def fullPath(self, fileName):
  29         if os.path.isabs(fileName):
  30             absPath = fileName
  31         elif self.baseLoadDir:
  32             absPath = os.path.join(self.baseLoadDir, fileName)
  33         else:
  34             absPath = os.path.abspath(fileName)
  35         return absPath
  36
  37     def setPrototype(self, fileName, loadedFile):
  38         absPath = self.fullPath(fileName)
  39         mtime = time.time() + 31536000.0 # Make sure prototypes aren't replaced by files on disk
  40         self.cache[absPath] = (mtime, loadedFile)
  41
  42     def update(self, loader):
  43         self.cache.update(loader.cache)
  44
  45     def clear(self):
  46         self.cache.clear()
  47
  48     def delete(self, fileName):
  49         absPath = self.fullPath(fileName)
  50         del self.cache[absPath]
  51
  52     def needsLoad(self, fileName):
  53         absPath = self.fullPath(fileName)
  54         try:
  55             cached = self.cache[absPath]
  56             cachedTime = cached[0]
  57             if cachedTime >= os.path.getmtime(absPath):
  58                 return False
  59         except KeyError:
  60             pass
  61         return True
  62
  63     def load(self, fileName, loader):
  64         absPath = self.fullPath(fileName)
  65         loadedFile = None
  66         try:
  67             cached = self.cache[absPath]
  68         except KeyError:
  69             cached = None
  70
  71         if cached:
  72             cachedTime = cached[0]
  73             # ToDO We might need smarter logic for checking if a file needs to be reloaded
  74             # ToDo We need a way to disable checking if this is a production server
  75             if cachedTime >= os.path.getmtime(absPath):
  76                 loadedFile = cached[1]
  77
  78         if not loadedFile:
  79             targetFile = file(absPath)
  80             try:
  81                 mtime = os.path.getmtime(absPath)
  82                 loadedFile = loader(targetFile)
  83                 self.cache[absPath] = (mtime, loadedFile)
  84             finally:
  85                 targetFile.close()
  86         return loadedFile
  87