Lib/lib2to3/main.py

   1 """
   2 Main program for 2to3.
   3 """
   4
   5 import sys
   6 import os
   7 import difflib
   8 import logging
   9 import shutil
  10 import optparse
  11
  12 from . import refactor
  13
  14
  15 def diff_texts(a, b, filename):
  16     """Return a unified diff of two strings."""
  17     a = a.splitlines()
  18     b = b.splitlines()
  19     return difflib.unified_diff(a, b, filename, filename,
  20                                 "(original)", "(refactored)",
  21                                 lineterm="")
  22
  23
  24 class StdoutRefactoringTool(refactor.MultiprocessRefactoringTool):
  25     """
  26     Prints output to stdout.
  27     """
  28
  29     def __init__(self, fixers, options, explicit, nobackups, show_diffs):
  30         self.nobackups = nobackups
  31         self.show_diffs = show_diffs
  32         super(StdoutRefactoringTool, self).__init__(fixers, options, explicit)
  33
  34     def log_error(self, msg, *args, **kwargs):
  35         self.errors.append((msg, args, kwargs))
  36         self.logger.error(msg, *args, **kwargs)
  37
  38     def write_file(self, new_text, filename, old_text, encoding):
  39         if not self.nobackups:
  40             # Make backup
  41             backup = filename + ".bak"
  42             if os.path.lexists(backup):
  43                 try:
  44                     os.remove(backup)
  45                 except os.error, err:
  46                     self.log_message("Can't remove backup %s", backup)
  47             try:
  48                 os.rename(filename, backup)
  49             except os.error, err:
  50                 self.log_message("Can't rename %s to %s", filename, backup)
  51         # Actually write the new file
  52         write = super(StdoutRefactoringTool, self).write_file
  53         write(new_text, filename, old_text, encoding)
  54         if not self.nobackups:
  55             shutil.copymode(backup, filename)
  56
  57     def print_output(self, old, new, filename, equal):
  58         if equal:
  59             self.log_message("No changes to %s", filename)
  60         else:
  61             self.log_message("Refactored %s", filename)
  62             if self.show_diffs:
  63                 for line in diff_texts(old, new, filename):
  64                     print line
  65
  66
  67 def warn(msg):
  68     print >> sys.stderr, "WARNING: %s" % (msg,)
  69
  70
  71 def main(fixer_pkg, args=None):
  72     """Main program.
  73
  74     Args:
  75         fixer_pkg: the name of a package where the fixers are located.
  76         args: optional; a list of command line arguments. If omitted,
  77               sys.argv[1:] is used.
  78
  79     Returns a suggested exit status (0, 1, 2).
  80     """
  81     # Set up option parser
  82     parser = optparse.OptionParser(usage="2to3 [options] file|dir ...")
  83     parser.add_option("-d", "--doctests_only", action="store_true",
  84                       help="Fix up doctests only")
  85     parser.add_option("-f", "--fix", action="append", default=[],
  86                       help="Each FIX specifies a transformation; default: all")
  87     parser.add_option("-j", "--processes", action="store", default=1,
  88                       type="int", help="Run 2to3 concurrently")
  89     parser.add_option("-x", "--nofix", action="append", default=[],
  90                       help="Prevent a fixer from being run.")
  91     parser.add_option("-l", "--list-fixes", action="store_true",
  92                       help="List available transformations (fixes/fix_*.py)")
  93     parser.add_option("-p", "--print-function", action="store_true",
  94                       help="Modify the grammar so that print() is a function")
  95     parser.add_option("-v", "--verbose", action="store_true",
  96                       help="More verbose logging")
  97     parser.add_option("--no-diffs", action="store_true",
  98                       help="Don't show diffs of the refactoring")
  99     parser.add_option("-w", "--write", action="store_true",
 100                       help="Write back modified files")
 101     parser.add_option("-n", "--nobackups", action="store_true", default=False,
 102                       help="Don't write backups for modified files.")
 103
 104     # Parse command line arguments
 105     refactor_stdin = False
 106     flags = {}
 107     options, args = parser.parse_args(args)
 108     if not options.write and options.no_diffs:
 109         warn("not writing files and not printing diffs; that's not very useful")
 110     if not options.write and options.nobackups:
 111         parser.error("Can't use -n without -w")
 112     if options.list_fixes:
 113         print "Available transformations for the -f/--fix option:"
 114         for fixname in refactor.get_all_fix_names(fixer_pkg):
 115             print fixname
 116         if not args:
 117             return 0
 118     if not args:
 119         print >> sys.stderr, "At least one file or directory argument required."
 120         print >> sys.stderr, "Use --help to show usage."
 121         return 2
 122     if "-" in args:
 123         refactor_stdin = True
 124         if options.write:
 125             print >> sys.stderr, "Can't write to stdin."
 126             return 2
 127     if options.print_function:
 128         flags["print_function"] = True
 129
 130     # Set up logging handler
 131     level = logging.DEBUG if options.verbose else logging.INFO
 132     logging.basicConfig(format='%(name)s: %(message)s', level=level)
 133
 134     # Initialize the refactoring tool
 135     avail_fixes = set(refactor.get_fixers_from_package(fixer_pkg))
 136     unwanted_fixes = set(fixer_pkg + ".fix_" + fix for fix in options.nofix)
 137     explicit = set()
 138     if options.fix:
 139         all_present = False
 140         for fix in options.fix:
 141             if fix == "all":
 142                 all_present = True
 143             else:
 144                 explicit.add(fixer_pkg + ".fix_" + fix)
 145         requested = avail_fixes.union(explicit) if all_present else explicit
 146     else:
 147         requested = avail_fixes.union(explicit)
 148     fixer_names = requested.difference(unwanted_fixes)
 149     rt = StdoutRefactoringTool(sorted(fixer_names), flags, sorted(explicit),
 150                                options.nobackups, not options.no_diffs)
 151
 152     # Refactor all files and directories passed as arguments
 153     if not rt.errors:
 154         if refactor_stdin:
 155             rt.refactor_stdin()
 156         else:
 157             try:
 158                 rt.refactor(args, options.write, options.doctests_only,
 159                             options.processes)
 160             except refactor.MultiprocessingUnsupported:
 161                 assert options.processes > 1
 162                 print >> sys.stderr, "Sorry, -j isn't " \
 163                     "supported on this platform."
 164                 return 1
 165         rt.summarize()
 166
 167     # Return error status (0 if rt.errors is zero)
 168     return int(bool(rt.errors))