[wwwsearch-commits] r21663 - in wwwsearch/ClientCookie/trunk: ClientCookie test

[jjlee at codespeak.net]

Author: jjlee
Date: Mon Jan  2 23:32:08 2006
New Revision: 21663

Modified:
   wwwsearch/ClientCookie/trunk/ClientCookie/_Util.py
   wwwsearch/ClientCookie/trunk/test/test_misc.py
Log:
Fix ballsup in seek-past-end-of-cache case in seek_wrapper; Also fix invariant and remove a no-op .seek() call on the cache

Modified: wwwsearch/ClientCookie/trunk/ClientCookie/_Util.py
==============================================================================
--- wwwsearch/ClientCookie/trunk/ClientCookie/_Util.py	(original)
+++ wwwsearch/ClientCookie/trunk/ClientCookie/_Util.py	Mon Jan  2 23:32:08 2006
@@ -1,6 +1,6 @@
 """Python backwards-compat., date/time routines, seekable file object wrapper.
 
- Copyright 2002-2004 John J Lee <jjl at pobox.com>
+ Copyright 2002-2006 John J Lee <jjl at pobox.com>
 
 This code is free software; you can redistribute it and/or modify it under
 the terms of the BSD License (see the file COPYING included with the
@@ -369,11 +369,19 @@
     return _str2time(day, mon, yr, hr, min, sec, tz)
 
 
-
 # XXX Andrew Dalke kindly sent me a similar class in response to my request on
 # comp.lang.python, which I then proceeded to lose.  I wrote this class
 # instead, but I think he's released his code publicly since, could pinch the
 # tests from it, at least...
+
+# for testing seek_wrapper invariant
+# module ipdc is here:
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/436834
+## try:
+##     from ipdbc import ContractBase
+## except ImportError:
+##     pass
+## class seek_wrapper(ContractBase):
 class seek_wrapper:
     """Adds a seek method to a file object.
 
@@ -397,15 +405,19 @@
     # instance.  Seems to be some cStringIO.StringIO problem on 1.5.2 -- I
     # get a StringOobject, with no readlines method.
 
-    # Invariant: the end of the cache is always at the same place as the
-    # end of the wrapped file:
-    # self.wrapped.tell() == self.__cache.tell()
+    # XXX Does this work sensibly in the face of exceptions raised by .read()
+    # / .readline()??
 
     def __init__(self, wrapped):
         self.wrapped = wrapped
         self.__have_readline = hasattr(self.wrapped, "readline")
         self.__cache = StringIO()
 
+    def invariant(self):
+        # The end of the cache is always at the same place as the end of the
+        # wrapped file.
+        return self.wrapped.tell() == len(self.__cache.getvalue())
+
     def __getattr__(self, name):
         wrapped = self.__dict__.get("wrapped")
         if wrapped:
@@ -424,6 +436,7 @@
             # read everything
             to_read = None
         if to_read is None or to_read >= 0:
+            self.__cache.seek(0, 2)
             if to_read is None:
                 self.__cache.write(self.wrapped.read())
             else:
@@ -437,9 +450,6 @@
 
     def read(self, size=-1):
         pos = self.__cache.tell()
-
-        self.__cache.seek(pos)
-
         end = len(self.__cache.getvalue())
         available = end - pos
 

Modified: wwwsearch/ClientCookie/trunk/test/test_misc.py
==============================================================================
--- wwwsearch/ClientCookie/trunk/test/test_misc.py	(original)
+++ wwwsearch/ClientCookie/trunk/test/test_misc.py	Mon Jan  2 23:32:08 2006
@@ -31,6 +31,7 @@
         except ImportError:
             from ClientCookie._ClientCookie import StopIteration
         from ClientCookie._Util import seek_wrapper
+        from ClientCookie._Debug import warn
         text = """\
 The quick brown fox
 jumps over the lazy
@@ -106,6 +107,14 @@
         else:
             assert False, "StopIteration not raised"
 
+        fh = TestUnSeekable(text)
+        sfh = seek_wrapper(fh)
+        sfh.read(10)
+        sfh.seek(5)
+        self.assert_(sfh.invariant())
+        sfh.seek(0, 2)
+        self.assert_(sfh.invariant())
+
 
 if __name__ == "__main__":
     import unittest