Add initial support for color output in the build system

lib/naclports/__main__.py

 # Copyright (c) 2013 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Tool for manipulating naclports packages in python.
 
 This tool can be used to for working with naclports packages.
 It can also be incorporated into other tools that need to
 work with packages (e.g. 'update_mirror.py' uses it to iterate
 through all packages and mirror them on Google Cloud Storage).
@@ skipping 10 matching lines @@
   sys.exit(1)
 
 import argparse
 
 sys.path.append(os.path.dirname(os.path.dirname(__file__)))
 
 from naclports import configuration, error, source_package, util, paths
 import naclports.package
 
 
-def PrintStatus(msg):
-  sys.stderr.write('naclports: %s\n' % msg)
+def PrintError(msg):
+  sys.stderr.write('naclports: %s\n' % util.Color(str(msg), 'red'))
 
 
 def CmdList(config, options, args):
   """List installed packages"""
   if len(args):
     raise error.Error('list command takes no arguments')
   if options.all:
     iterator = source_package.SourcePackageIterator()
   else:
     iterator = naclports.package.InstalledPackageIterator(config)
@@ skipping 34 matching lines @@
     sys.stdout.write(filename + '\n')
 
 
 def CmdPkgDownload(package, options):
   """Download sources for given package(s)"""
   package.Download()
 
 
 def CmdPkgUscan(package, options):
   """Use Debian's 'uscan' to check for upstream versions."""
+  if not package.URL:
+    return 0
+
   if package.VERSION not in package.URL:
-    PrintStatus('%s: uscan only works if VERSION is embedded in URL' %
+    PrintError('%s: uscan only works if VERSION is embedded in URL' %
                 package.NAME)
     return 0
 
   temp_fd, temp_file = tempfile.mkstemp('naclports_watchfile')
   try:
     with os.fdopen(temp_fd, 'w') as f:
       uscan_url = package.URL.replace(package.VERSION, '(.+)')
       uscan_url = uscan_url.replace('download.sf.net', 'sf.net')
       util.Trace('uscan pattern: %s' % uscan_url)
       f.write("version = 3\n")
@@ skipping 111 matching lines @@
     epilog += '  %-12s - %s\n' % (name, function.__doc__)
 
   parser = argparse.ArgumentParser(prog='naclports', description=__doc__,
       formatter_class=argparse.RawDescriptionHelpFormatter, epilog=epilog)
   parser.add_argument('-v', '--verbose', action='store_true',
                       help='Output extra information.')
   parser.add_argument('-V', '--verbose-build', action='store_true',
                       help='Make builds verbose (e.g. pass V=1 to make')
   parser.add_argument('--all', action='store_true',
                       help='Perform action on all known ports.')
+  parser.add_argument('--color', choices=('always', 'never', 'auto'),
+                      help='Enabled color terminal output', default='auto')
   parser.add_argument('-f', '--force', action='store_const', const='build',
                       help='Force building specified targets, '
                       'even if timestamps would otherwise skip it.')
   parser.add_argument('--from-source', action='store_true',
                       help='Always build from source rather than downloading '
                       'prebuilt packages.')
   parser.add_argument('-F', '--force-all', action='store_const', const='all',
                       dest='force', help='Force building target and all '
                       'dependencies, even if timestamps would otherwise skip '
                       'them.')
@@ skipping 20 matching lines @@
   if args.verbose_build:
     os.environ['VERBOSE'] = '1'
   else:
     if 'VERBOSE' in os.environ:
       del os.environ['VERBOSE']
     if 'V' in os.environ:
       del os.environ['V']
 
   util.CheckSDKRoot()
   config = configuration.Configuration(args.arch, args.toolchain, args.debug)
+  util.color_mode = args.color
+  if args.color == 'never':
+    util.Color.enabled = False
+  elif args.color == 'always':
+    util.Color.enabled = True
 
   if args.command in base_commands:
     base_commands[args.command](config, args, args.pkg)
     return 0
 
   if args.command not in pkg_commands:
     parser.error("Unknown subcommand: '%s'\n"
                  'See --help for available commands.' % args.command)
 
   if len(args.pkg) and args.all:
@@ skipping 29 matching lines @@
       if args.command in installed_pkg_commands:
         p = naclports.package.CreateInstalledPackage(package_name, config)
       else:
         p = source_package.CreatePackage(package_name, config)
       DoCmd(p)
 
 def main(args):
   try:
     RunMain(args)
   except KeyboardInterrupt:
-    PrintStatus('interrupted')
+    PrintError('interrupted')
     return 1
   except error.Error as e:
-    PrintStatus(str(e))
+    PrintError(str(e))
     return 1
 
   return 0
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))