Use mapfile to only create & parse mapfile strings, not files

1 files changed, 116 insertions, 0 deletions

diff --git a/libbe/storage/util/mapfile.py b/libbe/storage/util/mapfile.py
new file mode 100644
index 0000000..a8d5516
--- /dev/null
+++ b/libbe/storage/util/mapfile.py
@@ -0,0 +1,116 @@
+# Copyright (C) 2005-2009 Aaron Bentley and Panometrics, Inc.
+#                         Gianluca Montecchi <gian@grys.it>
+#                         W. Trevor King <wking@drexel.edu>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+"""
+Provide a means of saving and loading dictionaries of parameters.  The
+saved "mapfiles" should be clear, flat-text files, and allow easy merging of
+independent/conflicting changes.
+"""
+
+import errno
+import os.path
+import yaml
+
+import libbe
+if libbe.TESTING == True:
+    import doctest
+
+
+class IllegalKey(Exception):
+    def __init__(self, key):
+        Exception.__init__(self, 'Illegal key "%s"' % key)
+        self.key = key
+
+class IllegalValue(Exception):
+    def __init__(self, value):
+        Exception.__init__(self, 'Illegal value "%s"' % value)
+        self.value = value 
+
+def generate(map):
+    """Generate a YAML mapfile content string.
+    >>> generate({"q":"p"})
+    'q: p\\n\\n'
+    >>> generate({"q":u"Fran\u00e7ais"})
+    'q: Fran\\xc3\\xa7ais\\n\\n'
+    >>> generate({"q":u"hello"})
+    'q: hello\\n\\n'
+    >>> generate({"q=":"p"})
+    Traceback (most recent call last):
+    IllegalKey: Illegal key "q="
+    >>> generate({"q:":"p"})
+    Traceback (most recent call last):
+    IllegalKey: Illegal key "q:"
+    >>> generate({"q\\n":"p"})
+    Traceback (most recent call last):
+    IllegalKey: Illegal key "q\\n"
+    >>> generate({"":"p"})
+    Traceback (most recent call last):
+    IllegalKey: Illegal key ""
+    >>> generate({">q":"p"})
+    Traceback (most recent call last):
+    IllegalKey: Illegal key ">q"
+    >>> generate({"q":"p\\n"})
+    Traceback (most recent call last):
+    IllegalValue: Illegal value "p\\n"
+    """
+    keys = map.keys()
+    keys.sort()
+    for key in keys:
+        try:
+            assert not key.startswith('>')
+            assert('\n' not in key)
+            assert('=' not in key)
+            assert(':' not in key)
+            assert(len(key) > 0)
+        except AssertionError:
+            raise IllegalKey(unicode(key).encode('unicode_escape'))
+        if '\n' in map[key]:
+            raise IllegalValue(unicode(map[key]).encode('unicode_escape'))
+
+    lines = []
+    for key in keys:
+        lines.append(yaml.safe_dump({key: map[key]},
+                                    default_flow_style=False,
+                                    allow_unicode=True))
+        lines.append('')
+    return '\n'.join(lines)
+
+def parse(contents):
+    """
+    Parse a YAML mapfile string.
+    >>> parse('q: p\\n\\n')['q']
+    'p'
+    >>> parse('q: \\'p\\'\\n\\n')['q']
+    'p'
+    >>> contents = generate({"a":"b", "c":"d", "e":"f"})
+    >>> dict = parse(contents)
+    >>> dict["a"]
+    'b'
+    >>> dict["c"]
+    'd'
+    >>> dict["e"]
+    'f'
+    >>> contents = generate({"q":u"Fran\u00e7ais"})
+    >>> dict = parse(contents)
+    >>> dict["q"]
+    u'Fran\\xe7ais'
+    """
+    return yaml.load(contents) or {}
+
+if libbe.TESTING == True:
+    suite = doctest.DocTestSuite()