pycolor: Wrong filename given -> print error

When a user wanted to colorize a file, which doesn't exist, IPython
would crash. This commit changes this, so the user gets a usefull
message about the wrong filename.

This fixes RH bug  #628742.

Signed-off-by: Thomas Spura <[e-mail]>

IPython/utils/PyColorize.py

@@ -1,299 +1,303 b''
 # -*- coding: utf-8 -*-
 """
 Class and program to colorize python source code for ANSI terminals.
 
 Based on an HTML code highlighter by Jurgen Hermann found at:
 http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52298
 
 Modifications by Fernando Perez ([e-mail]).
 
 Information on the original HTML highlighter follows:
 
 MoinMoin - Python Source Parser
 
 Title: Colorize Python source using the built-in tokenizer
 
 Submitter: Jurgen Hermann
 Last Updated:2001/04/06
 
 Version no:1.2
 
 Description:
 
 This code is part of MoinMoin (http://moin.sourceforge.net/) and converts
 Python source code to HTML markup, rendering comments, keywords,
 operators, numeric and string literals in different colors.
 
 It shows how to use the built-in keyword, token and tokenize modules to
 scan Python source code and re-emit it with no changes to its original
 formatting (which is the hard part).
 """
 
 __all__ = ['ANSICodeColors','Parser']
 
 _scheme_default = 'Linux'
 
 # Imports
 import cStringIO
 import keyword
 import os
 import optparse
 import sys
 import token
 import tokenize
 
 from IPython.utils.coloransi import *
 
 #############################################################################
 ### Python Source Parser (does Hilighting)
 #############################################################################
 
 _KEYWORD = token.NT_OFFSET + 1
 _TEXT    = token.NT_OFFSET + 2
 
 #****************************************************************************
 # Builtin color schemes
 
 Colors = TermColors  # just a shorthand
 
 # Build a few color schemes
 NoColor = ColorScheme(
     'NoColor',{
     token.NUMBER     : Colors.NoColor,
     token.OP         : Colors.NoColor,
     token.STRING     : Colors.NoColor,
     tokenize.COMMENT : Colors.NoColor,
     token.NAME       : Colors.NoColor,
     token.ERRORTOKEN : Colors.NoColor,
 
     _KEYWORD         : Colors.NoColor,
     _TEXT            : Colors.NoColor,
 
     'normal'         : Colors.NoColor  # color off (usu. Colors.Normal)
     }  )
 
 LinuxColors = ColorScheme(
     'Linux',{
     token.NUMBER     : Colors.LightCyan,
     token.OP         : Colors.Yellow,
     token.STRING     : Colors.LightBlue,
     tokenize.COMMENT : Colors.LightRed,
     token.NAME       : Colors.White,
     token.ERRORTOKEN : Colors.Red,
 
     _KEYWORD         : Colors.LightGreen,
     _TEXT            : Colors.Yellow,
 
     'normal'         : Colors.Normal  # color off (usu. Colors.Normal)
     } )
 
 LightBGColors = ColorScheme(
     'LightBG',{
     token.NUMBER     : Colors.Cyan,
     token.OP         : Colors.Blue,
     token.STRING     : Colors.Blue,
     tokenize.COMMENT : Colors.Red,
     token.NAME       : Colors.Black,
     token.ERRORTOKEN : Colors.Red,
 
     _KEYWORD         : Colors.Green,
     _TEXT            : Colors.Blue,
 
     'normal'         : Colors.Normal  # color off (usu. Colors.Normal)
     }  )
 
 # Build table of color schemes (needed by the parser)
 ANSICodeColors = ColorSchemeTable([NoColor,LinuxColors,LightBGColors],
                                   _scheme_default)
 
 class Parser:
     """ Format colored Python source.
     """
 
     def __init__(self, color_table=None,out = sys.stdout):
         """ Create a parser with a specified color table and output channel.
 
         Call format() to process code.
         """
         self.color_table = color_table and color_table or ANSICodeColors
         self.out = out
 
     def format(self, raw, out = None, scheme = ''):
         return self.format2(raw, out, scheme)[0]
 
     def format2(self, raw, out = None, scheme = ''):
         """ Parse and send the colored source.
 
         If out and scheme are not specified, the defaults (given to
         constructor) are used.
 
         out should be a file-type object. Optionally, out can be given as the
         string 'str' and the parser will automatically return the output in a
         string."""
         
         string_output = 0
         if out == 'str' or self.out == 'str' or \
            isinstance(self.out,cStringIO.OutputType):
             # XXX - I don't really like this state handling logic, but at this
             # point I don't want to make major changes, so adding the
             # isinstance() check is the simplest I can do to ensure correct
             # behavior.
             out_old = self.out
             self.out = cStringIO.StringIO()
             string_output = 1
         elif out is not None:
             self.out = out
 
         # Fast return of the unmodified input for NoColor scheme
         if scheme == 'NoColor':
             error = False
             self.out.write(raw)
             if string_output:
                 return raw,error
             else:
                 return None,error
         
         # local shorthands
         colors = self.color_table[scheme].colors
         self.colors = colors # put in object so __call__ sees it
 
         # Remove trailing whitespace and normalize tabs
         self.raw = raw.expandtabs().rstrip()
         
         # store line offsets in self.lines
         self.lines = [0, 0]
         pos = 0
         raw_find = self.raw.find
         lines_append = self.lines.append
         while 1:
             pos = raw_find('\n', pos) + 1
             if not pos: break
             lines_append(pos)
         lines_append(len(self.raw))
 
         # parse the source and write it
         self.pos = 0
         text = cStringIO.StringIO(self.raw)
 
         error = False
         try:
             tokenize.tokenize(text.readline, self)
         except tokenize.TokenError, ex:
             msg = ex[0]
             line = ex[1][0]
             self.out.write("%s\n\n*** ERROR: %s%s%s\n" %
                            (colors[token.ERRORTOKEN],
                             msg, self.raw[self.lines[line]:],
                             colors.normal)
                            )
             error = True
         self.out.write(colors.normal+'\n')
         if string_output:
             output = self.out.getvalue()
             self.out = out_old
             return (output, error)
         return (None, error)
 
     def __call__(self, toktype, toktext, (srow,scol), (erow,ecol), line):
         """ Token handler, with syntax highlighting."""
 
         # local shorthands
         colors = self.colors
         owrite = self.out.write
 
         # line separator, so this works across platforms
         linesep = os.linesep
 
         # calculate new positions
         oldpos = self.pos
         newpos = self.lines[srow] + scol
         self.pos = newpos + len(toktext)
 
         # handle newlines
         if toktype in [token.NEWLINE, tokenize.NL]:
             owrite(linesep)
             return
 
         # send the original whitespace, if needed
         if newpos > oldpos:
             owrite(self.raw[oldpos:newpos])
 
         # skip indenting tokens
         if toktype in [token.INDENT, token.DEDENT]:
             self.pos = newpos
             return
 
         # map token type to a color group
         if token.LPAR <= toktype and toktype <= token.OP:
             toktype = token.OP
         elif toktype == token.NAME and keyword.iskeyword(toktext):
             toktype = _KEYWORD
         color = colors.get(toktype, colors[_TEXT])
 
         #print '<%s>' % toktext,    # dbg
 
         # Triple quoted strings must be handled carefully so that backtracking
         # in pagers works correctly. We need color terminators on _each_ line.
         if linesep in toktext:
             toktext = toktext.replace(linesep, '%s%s%s' %
                                       (colors.normal,linesep,color))
 
         # send text
         owrite('%s%s%s' % (color,toktext,colors.normal))
             
 def main(argv=None):
     """Run as a command-line script: colorize a python file or stdin using ANSI
     color escapes and print to stdout.
 
     Inputs:
 
       - argv(None): a list of strings like sys.argv[1:] giving the command-line
         arguments. If None, use sys.argv[1:].
     """
 
     usage_msg = """%prog [options] [filename]
 
 Colorize a python file or stdin using ANSI color escapes and print to stdout.
 If no filename is given, or if filename is -, read standard input."""
 
     parser = optparse.OptionParser(usage=usage_msg)
     newopt = parser.add_option
     newopt('-s','--scheme',metavar='NAME',dest='scheme_name',action='store',
            choices=['Linux','LightBG','NoColor'],default=_scheme_default,
            help="give the color scheme to use. Currently only 'Linux'\
  (default) and 'LightBG' and 'NoColor' are implemented (give without\
  quotes)")
 
     opts,args = parser.parse_args(argv)
 
     if len(args) > 1:
         parser.error("you must give at most one filename.")
 
     if len(args) == 0:
         fname = '-' # no filename given; setup to read from stdin
     else:
         fname = args[0]
 
     if fname == '-':
         stream = sys.stdin
     else:
-        stream = file(fname)
+        try:
+            stream = file(fname)
+        except IOError,msg:
+            print >> sys.stderr, msg
+            sys.exit(1)
 
     parser = Parser()
 
     # we need nested try blocks because pre-2.5 python doesn't support unified
     # try-except-finally
     try:
         try:
             # write colorized version to stdout
             parser.format(stream.read(),scheme=opts.scheme_name)
         except IOError,msg:
             # if user reads through a pager and quits, don't print traceback
             if msg.args != (32,'Broken pipe'):
                 raise
     finally:
         if stream is not sys.stdin:
             stream.close() # in case a non-handled exception happened above
 
 if __name__ == "__main__":
     main()