utils_prog: new program-specific unit incl. some moves from utils

Signed-off-by: Jan Pokorný <jpokorny@redhat.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/utils_prog.py b/utils_prog.py
new file mode 100644
index 0000000..591ebae
--- /dev/null
+++ b/utils_prog.py
@@ -0,0 +1,80 @@
+# -*- coding: UTF-8 -*-
+# Copyright 2014 Red Hat, Inc.
+# Part of clufter project
+# Licensed under GPLv2+ (a copy included | http://gnu.org/licenses/gpl-2.0.txt)
+"""Program-specific commons"""
+__author__ = "Jan Pokorný <jpokorny @at@ Red Hat .dot. com>"
+
+import logging
+from optparse import make_option
+from os import environ, path, pathsep
+from subprocess import Popen
+from sys import stderr, stdin
+
+from .error import ClufterError
+
+
+#
+# command-line options related
+#
+
+# dashes recommended by 5 of 4 terminal fanboys
+# NB underscores -> dashes swap is idempotent in regards to the member
+#    name of where optparse stores respective option value, but here
+#    the list of possible operations to preserve such property stops!
+#    + also to preserve reversibility/bijection, original ought to be
+#      free of the substituting character
+cli_decor = lambda x: x.replace('_', '-')
+cli_undecor = lambda x: x.replace('-', '_')
+
+# prioritize consonants, deprioritize vowels (except for the first letter
+# overall), which seems to be widely adopted technique for selecting short
+# options based on their long counterparts ;)
+# XXX could eventually also resort to using upper-case chars
+longopt_letters_reprio = \
+    lambda longopt: \
+        (lambda lo: \
+            lo[0] + ''.join(sorted(lo[1:],
+                                   key=lambda x: int(x.lower() in 'aeiouy')))
+        )(filter(lambda c: c.isalpha(), longopt))
+
+# extrapolate optparse.make_option to specifically-encoded "plural"
+make_options = lambda opt_decl: [make_option(*a, **kw) for a, kw in opt_decl]
+
+
+class OneoffWrappedStdinPopen(object):
+    """Singleton to watch for atmost one use of stdin in Popen context"""
+    def __init__(self):
+        self._used = False
+
+    def __call__(self, args, **kwargs):
+        if not 'stdin' in kwargs and '-' in args:
+            if self._used:
+                raise ClufterError(self, 'repeated use detected')
+            kwargs['stdin'] = stdin
+            # only the first '-' substituted
+            args[args.index('-')] = '/dev/stdin'
+            self._used |= True
+        return Popen(args, **kwargs)
+
+OneoffWrappedStdinPopen = OneoffWrappedStdinPopen()
+
+
+#
+# misc
+#
+
+def which(name, *where):
+    """Mimic `which' UNIX utility"""
+    where = tuple(path.abspath(i) for i in where)
+    if 'PATH' in environ:
+        use_path = tuple(i for i in environ['PATH'].split(pathsep)
+                         if len(i.strip()))
+    else:
+        use_path = ()
+    for p in where + use_path:
+        check = path.join(p, name)
+        if path.exists(check):
+            return check
+    else:
+        return None