Add class Options

The Options constructor takes an options string, parses it and
makes the options available via __getitem__().

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/Options.py

@@ -0,0 +1,125 @@
+import re
+import json
+from collections import OrderedDict
+from . import log
+import shlex
+
+class Options: # export
+
+    def __parse_json(self, spec):
+        spec = spec.strip()
+        if len(spec) < 3:
+            return None
+        if spec[0] != '{':
+            spec = '{' + spec + '}'
+        try:
+            return json.loads(spec, object_pairs_hook=OrderedDict)
+        except:
+            pass
+        return None
+
+    def __parse(self, opts_str):
+        r = self.__parse_json(opts_str)
+        if r is not None:
+            return r
+        r = OrderedDict()
+        opt_strs = shlex.split(opts_str)
+        for opt_str in opt_strs:
+            opt_str = re.sub('\s*=\s*', '=', opt_str)
+            sides = opt_str.split('=')
+            lhs = sides[0].strip()
+            if not len(lhs):
+                continue
+            if self.__allowed_keys and not lhs in self.__allowed_keys:
+                raise Exception('Field "{}" not supported'.format(lhs))
+            rhs = ' '.join(sides[1:]).strip() if len(sides) > 1 else self.__true_val
+            r[lhs] = rhs
+        return r
+
+    def __recache(self):
+        self.__list.clear()
+        self.__list = list(self.__dict)
+        self.__str = str(dict(self.__dict))
+
+    def __getitem__(self, key):
+        if not key in self.__dict.keys():
+            return None
+        return self.__dict[key]
+
+    def __str__(self):
+        return self.__str
+
+    def __repr__(self):
+        return self.__str
+
+    def __format__(self, fmt):
+        return self.__str
+
+    def __len__(self):
+        return len(self.__list)
+
+    def __contains__(self, keys):
+        if not type(keys) in [list, set]:
+            return keys in self.__dict.keys()
+        for key in keys:
+            if not key in self.__dict.keys():
+                return False
+        return True
+
+    def __iter__(self):
+        return iter(self.__list)
+
+    def __next__(self):
+        return next(self.__list)
+
+    def __init__(self, spec=None, delimiter=',', allowed_keys=None, true_val=True):
+        self.__true_val = true_val
+        self.__allowed_keys = None
+        self.__delimiter = delimiter
+        self.__spec = spec
+        self.__dict = OrderedDict() if spec is None else self.__parse(spec)
+        self.__list = []
+        self.__str = None
+        self.__recache()
+
+    def dump(self, prio):
+        caller = log.get_caller_pos()
+        for key, val in self.__dict.items():
+            log.slog(prio, "{}=\"{}\"".format(key, val))
+
+    def keys(self):
+        return self.__dict.keys()
+
+    def items(self):
+        return self.__dict.items()
+
+    def get(self, key, default=None, by_index=False):
+        if by_index:
+            if type(key) != int:
+                raise KeyError('Tried to get value from options string with ' +
+                        'index {} of type "{}": {}'.format(key, type(key), self.__spec))
+            if key >= len(self.__list):
+                if default is not None:
+                    return default
+                raise KeyError('Tried to get value from options string with ' +
+                        'index {} of {}: {}'.format(key, len(self.__list), self.__spec))
+            return self.__list[key]
+        if key in self.__dict.keys():
+            return self.__dict[key]
+        if default is not None:
+            return default
+        raise KeyError('Key "{}" is not present in options string: {}'.format(key, self.__spec))
+
+    def update(self, rhs):
+        if hasattr(rhs, 'items'):
+            for key, val in rhs.items():
+                self.__dict[key] = val
+            return
+        if isinstance(rhs, str):
+            self.update(self.__parse(rhs))
+            return
+        raise Exception('Tried to update options with object of incompatible type {}'.format(type(rhs)))
+
+    def append_to(self, obj):
+        for opt in self.__list:
+            setattr(obj, opt[0], opt[1])