Cheetah/ImportHooks.py

   1 #!/usr/bin/env python
   2 # $Id: ImportHooks.py,v 1.25 2006/06/20 19:23:27 tavis_rudd Exp $
   3
   4 """Provides some import hooks to allow Cheetah's .tmpl files to be imported
   5 directly like Python .py modules.
   6
   7 To use these:
   8   import Cheetah.ImportHooks
   9   Cheetah.ImportHooks.install()
  10
  11 Meta-Data
  12 ================================================================================
  13 Author: Tavis Rudd <tavis@damnsimple.com>
  14 License: This software is released for unlimited distribution under the
  15          terms of the MIT license.  See the LICENSE file.
  16 Version: $Revision: 1.25 $
  17 Start Date: 2001/03/30
  18 Last Revision Date: $Date: 2006/06/20 19:23:27 $
  19 """
  20 __author__ = "Tavis Rudd <tavis@damnsimple.com>"
  21 __revision__ = "$Revision: 1.25 $"[11:-2]
  22
  23 import sys
  24 import os.path
  25 import types
  26 import __builtin__
  27 import new
  28 import imp
  29 from threading import Lock
  30 import string
  31 import traceback
  32 from Cheetah import ImportManager
  33 from Cheetah.ImportManager import DirOwner
  34 from Cheetah.Compiler import Compiler
  35 from Cheetah.convertTmplPathToModuleName import convertTmplPathToModuleName
  36
  37 _installed = False
  38
  39 ##################################################
  40 ## HELPER FUNCS
  41
  42 _cacheDir = []
  43 def setCacheDir(cacheDir):
  44     global _cacheDir
  45     _cacheDir.append(cacheDir)
  46
  47 ##################################################
  48 ## CLASSES
  49
  50 class CheetahDirOwner(DirOwner):
  51     _lock = Lock()
  52     _acquireLock = _lock.acquire
  53     _releaseLock = _lock.release
  54
  55     templateFileExtensions = ('.tmpl',)
  56
  57     def getmod(self, name):
  58         try:
  59             self._acquireLock()
  60             mod = DirOwner.getmod(self, name)
  61             if mod:
  62                 return mod
  63
  64             for ext in self.templateFileExtensions:
  65                 tmplPath =  os.path.join(self.path, name + ext)
  66                 if os.path.exists(tmplPath):
  67                     try:
  68                         return self._compile(name, tmplPath)
  69                     except:
  70                         # @@TR: log the error
  71                         exc_txt = traceback.format_exc()
  72                         exc_txt ='  '+('  \n'.join(exc_txt.splitlines()))
  73                         raise ImportError(
  74                             'Error while compiling Cheetah module'
  75                         ' %(name)s, original traceback follows:\n%(exc_txt)s'%locals())
  76             ##
  77             return None
  78
  79         finally:
  80             self._releaseLock()
  81
  82     def _compile(self, name, tmplPath):
  83         ## @@ consider adding an ImportError raiser here
  84         code = str(Compiler(file=tmplPath, moduleName=name,
  85                             mainClassName=name))
  86         if _cacheDir:
  87             __file__ = os.path.join(_cacheDir[0],
  88                                     convertTmplPathToModuleName(tmplPath)) + '.py'
  89             try:
  90                 open(__file__, 'w').write(code)
  91             except OSError:
  92                 ## @@ TR: need to add some error code here
  93                 traceback.print_exc(file=sys.stderr)
  94                 __file__ = tmplPath
  95         else:
  96             __file__ = tmplPath
  97         co = compile(code+'\n', __file__, 'exec')
  98
  99         mod = imp.new_module(name)
 100         mod.__file__ = co.co_filename
 101         if _cacheDir:
 102             mod.__orig_file__ = tmplPath # @@TR: this is used in the WebKit
 103                                          # filemonitoring code
 104         mod.__co__ = co
 105         return mod
 106
 107
 108 ##################################################
 109 ## FUNCTIONS
 110
 111 def install(templateFileExtensions=('.tmpl',)):
 112     """Install the Cheetah Import Hooks"""
 113
 114     global _installed
 115     if not _installed:
 116         CheetahDirOwner.templateFileExtensions = templateFileExtensions
 117         import __builtin__
 118         if type(__builtin__.__import__) == types.BuiltinFunctionType:
 119             global __oldimport__
 120             __oldimport__ = __builtin__.__import__
 121             ImportManager._globalOwnerTypes.insert(0, CheetahDirOwner)
 122             #ImportManager._globalOwnerTypes.append(CheetahDirOwner)
 123             global _manager
 124             _manager=ImportManager.ImportManager()
 125             _manager.setThreaded()
 126             _manager.install()
 127
 128 def uninstall():
 129     """Uninstall the Cheetah Import Hooks"""
 130     global _installed
 131     if not _installed:
 132         import __builtin__
 133         if type(__builtin__.__import__) == types.MethodType:
 134             __builtin__.__import__ = __oldimport__
 135             global _manager
 136             del _manager
 137
 138 if __name__ == '__main__':
 139     install()