Validate end of line

Add EndOfLineChecker, wrapper for a file-like object that checks for consistent line ends. It checks that each line ends in CRLF or LF, that lines do not contain other random characters that look like new line separators and that every line in the file ends with the same end of line sequence. Fixes http://code.google.com/p/googletransitdatafeed/issues/detail?id=27

Make RecordingProblemReporter stricter. Uses of it now explicitly list every exception. Fix some bugs where we reported a semantic problem for a field that was missing or had syntax errors.

[Tom, 2008-06-25 18:58:51]

Please review

[Joe Hughes, 2008-06-30 20:44:04]

Looks good, just a few readability comments below.  I found myself wondering if
there are any other places where I assumed  that the problem reporting would
exit the control flow (like some of the if statements you changed), but I guess
we'll find them in future testing/use.

http://codereview.appspot.com/2428/diff/7/23
File test/testtransitfeed.py (right):

http://codereview.appspot.com/2428/diff/7/23#newcode65
Line 65: """Save all problems for later inspection."""
Please add documentation of _ignore_types

http://codereview.appspot.com/2428/diff/7/23#newcode135
Line 135: for l in f: pass
I admit to being puzzled by this idiom; would you mind adding a comment about
what you're accomplishing here?  Also "l" isn't a great variable name due to the
visual similarity to "1".

http://codereview.appspot.com/2428/diff/7/25
File transitfeed.py (right):

http://codereview.appspot.com/2428/diff/7/25#newcode2372
Line 2372: next() is called until it raises StopIteration.
Ah, now I understand the odd for... things in the test.  Should still be
commented there, though.  Maybe it would make sense for legibility to just make
a "CheckAllLines" method?

[Tom, 2008-06-30 21:20:31]

Fixed the problems you found. Thanks

http://codereview.appspot.com/2428/diff/7/25
File transitfeed.py (right):

http://codereview.appspot.com/2428/diff/7/25#newcode2372
Line 2372: next() is called until it raises StopIteration.
On 2008/06/30 20:44:05, Joe Hughes wrote:
> Ah, now I understand the odd for... things in the test.  Should still be
> commented there, though.  Maybe it would make sense for legibility to just
make
> a "CheckAllLines" method?

I tried that first but _ReadCSV is a generator. Either the check would only be
performed if you keep calling _ReadCSV until it raises StopIteration or we'd
need to expose a method that is called after calling _ReadCSV to do the final
check. Something like PEP 343 might make this simpler when released.

[Tom, 2008-06-30 21:37:37]

How about this?

http://codereview.appspot.com/2428/diff/7/23
File test/testtransitfeed.py (right):

http://codereview.appspot.com/2428/diff/7/23#newcode135
Line 135: for l in f: pass
On 2008/06/30 20:44:05, Joe Hughes wrote:
> I admit to being puzzled by this idiom; would you mind adding a comment about
> what you're accomplishing here?  Also "l" isn't a great variable name due to
the
> visual similarity to "1".

After chatting with Joe I factored out this cryptic little line.

[Joe Hughes, 2008-06-30 21:56:50]

Much better.  Ship it!