Allow conditional lit tests in Subzero, based on build flags.

pydir/ifatts.py

+#!/usr/bin/env python2
+
+import argparse
+import os
+import sys
+
+from utils import shellcmd
+
+def GetFileAttributes(Filename):
+  """Returns the set of names contained in file named Filename.
+  """
+  if not os.path.isfile(Filename):
+    return []

[jvoung (off chromium), 2014/10/15 21:57:05]

Should this ever happen, or should it be considered a user error?

[Karl, 2014/10/16 16:51:48]

Rethinking this, I agree this should be an error.

+  with open(Filename, 'r') as f:
+    return f.read().split()
+
+def hasFileAttributes(Filename, Attributes):

[jvoung (off chromium), 2014/10/15 21:57:05]

HasFileAttributes

[Karl, 2014/10/16 16:51:48]

Done.

+  """Returns true if the set of names in Attributes also appear
+     in the set of names contained in file named Filename.
+     """

[jvoung (off chromium), 2014/10/15 21:57:05]

I think the usual style is to line up the comments like this:

"""One liner.

More stuff.
Additional stuff.
"""

So, like you had with GetFileAttributes, the ending """ is lined up with the
beginning """.

[Karl, 2014/10/16 16:51:48]

Done.

+  return set(Attributes) <= set(GetFileAttributes(Filename))
+
+def main():
+  """Check if the set attributes (i.e. names), contained in FILE,
+     contains the attributes defined by --att=ATTRIBUTE arguments. If
+     so, runs in a shell the command defined by the remaining
+     arguments. Otherwise, quits (generating no output) and returns
+     success.
+     """
+  argparser = argparse.ArgumentParser(
+    description='    ' + main.__doc__,
+    formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+  argparser.add_argument('file', metavar='FILE',
+                         help='File defining attributes to check against.')
+  argparser.add_argument('--att', required=False, default=[],
+                         action='append', metavar='ATTRIBUTE',
+                         help='Attribute to check. May be repeated.')
+  argparser.add_argument('--echo-cmd', required=False,
+                         action='store_true',
+                         help='Trace the command before running.')
+  argparser.add_argument('--command', nargs=argparse.REMAINDER,
+                         help='Command to run if attributes found.')
+
+  args = argparser.parse_args()
+
+  # Quit early if no command to run.
+  if not args.command:
+    return 0

[jvoung (off chromium), 2014/10/15 21:57:05]

Should this ever happen, or should it be considered a user error?

[Jim Stichnoth, 2014/10/15 22:23:54]

All but the last return should probably be "return 1".

Also, document in the docstring that it returns (to the shell) 0 on success and
1 on failure.

[Karl, 2014/10/16 16:51:48]

Actually, the last 2 should return 0! The conditional test is defined by the
second return, and should succeed with no output in this case.

The first return I have replaced with a runtime exception so that the failure is
cleanly reported.

[Karl, 2014/10/16 16:51:48]

Now that I have simplified this python file, and --command is more explicit, I
agree that this should be an error. Modifying.

+
+  # Quit early if the executable doesn't support expected build attributes.
+  if not hasFileAttributes(args.file, args.att):
+    return 0
+
+  stdout_result = shellcmd(args.command, echo=args.echo_cmd)
+  if not args.echo_cmd:
+    sys.stdout.write(stdout_result)
+
+  return 0
+
+if __name__ == '__main__':
+    main()

[Jim Stichnoth, 2014/10/15 22:23:54]

indent 2 spaces

[Karl, 2014/10/16 16:51:48]

Done.