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 as err:
  46                     self.log_message("Can't remove backup %s", backup)
  47             try:
  48                 os.rename(filename, backup)
  49             except os.error as 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                 diff_lines = diff_texts(old, new, filename)
  64                 try:
  65                     for line in diff_lines:
  66                         print(line)
  67                 except UnicodeEncodeError:
  68                     warn("couldn't encode %s's diff for your terminal" %
  69                          (filename,))
  70                     return
  71
  72 def warn(msg):
  73     print("WARNING: %s" % (msg,), file=sys.stderr)
  74
  75
  76 def main(fixer_pkg, args=None):
  77     """Main program.
  78
  79     Args:
  80         fixer_pkg: the name of a package where the fixers are located.
  81         args: optional; a list of command line arguments. If omitted,
  82               sys.argv[1:] is used.
  83
  84     Returns a suggested exit status (0, 1, 2).
  85     """
  86     # Set up option parser
  87     parser = optparse.OptionParser(usage="2to3 [options] file|dir ...")
  88     parser.add_option("-d", "--doctests_only", action="store_true",
  89                       help="Fix up doctests only")
  90     parser.add_option("-f", "--fix", action="append", default=[],
  91                       help="Each FIX specifies a transformation; default: all")
  92     parser.add_option("-j", "--processes", action="store", default=1,
  93                       type="int", help="Run 2to3 concurrently")
  94     parser.add_option("-x", "--nofix", action="append", default=[],
  95                       help="Prevent a fixer from being run.")
  96     parser.add_option("-l", "--list-fixes", action="store_true",
  97                       help="List available transformations (fixes/fix_*.py)")
  98     parser.add_option("-p", "--print-function", action="store_true",
  99                       help="Modify the grammar so that print() is a function")
 100     parser.add_option("-v", "--verbose", action="store_true",
 101                       help="More verbose logging")
 102     parser.add_option("--no-diffs", action="store_true",
 103                       help="Don't show diffs of the refactoring")
 104     parser.add_option("-w", "--write", action="store_true",
 105                       help="Write back modified files")
 106     parser.add_option("-n", "--nobackups", action="store_true", default=False,
 107                       help="Don't write backups for modified files.")
 108
 109     # Parse command line arguments
 110     refactor_stdin = False
 111     flags = {}
 112     options, args = parser.parse_args(args)
 113     if not options.write and options.no_diffs:
 114         warn("not writing files and not printing diffs; that's not very useful")
 115     if not options.write and options.nobackups:
 116         parser.error("Can't use -n without -w")
 117     if options.list_fixes:
 118         print("Available transformations for the -f/--fix option:")
 119         for fixname in refactor.get_all_fix_names(fixer_pkg):
 120             print(fixname)
 121         if not args:
 122             return 0
 123     if not args:
 124         print("At least one file or directory argument required.", file=sys.stderr)
 125         print("Use --help to show usage.", file=sys.stderr)
 126         return 2
 127     if "-" in args:
 128         refactor_stdin = True
 129         if options.write:
 130             print("Can't write to stdin.", file=sys.stderr)
 131             return 2
 132     if options.print_function:
 133         flags["print_function"] = True
 134
 135     # Set up logging handler
 136     level = logging.DEBUG if options.verbose else logging.INFO
 137     logging.basicConfig(format='%(name)s: %(message)s', level=level)
 138
 139     # Initialize the refactoring tool
 140     avail_fixes = set(refactor.get_fixers_from_package(fixer_pkg))
 141     unwanted_fixes = set(fixer_pkg + ".fix_" + fix for fix in options.nofix)
 142     explicit = set()
 143     if options.fix:
 144         all_present = False
 145         for fix in options.fix:
 146             if fix == "all":
 147                 all_present = True
 148             else:
 149                 explicit.add(fixer_pkg + ".fix_" + fix)
 150         requested = avail_fixes.union(explicit) if all_present else explicit
 151     else:
 152         requested = avail_fixes.union(explicit)
 153     fixer_names = requested.difference(unwanted_fixes)
 154     rt = StdoutRefactoringTool(sorted(fixer_names), flags, sorted(explicit),
 155                                options.nobackups, not options.no_diffs)
 156
 157     # Refactor all files and directories passed as arguments
 158     if not rt.errors:
 159         if refactor_stdin:
 160             rt.refactor_stdin()
 161         else:
 162             try:
 163                 rt.refactor(args, options.write, options.doctests_only,
 164                             options.processes)
 165             except refactor.MultiprocessingUnsupported:
 166                 assert options.processes > 1
 167                 print("Sorry, -j isn't supported on this platform.",
 168                       file=sys.stderr)
 169                 return 1
 170         rt.summarize()
 171
 172     # Return error status (0 if rt.errors is zero)
 173     return int(bool(rt.errors))