1 files changed, 111 insertions, 0 deletions
diff --git a/pylint/config/options_provider_mixin.py b/pylint/config/options_provider_mixin.py
new file mode 100644
index 000000000..cae6d5865
--- /dev/null
+++ b/pylint/config/options_provider_mixin.py
@@ -0,0 +1,111 @@
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
+
+
+import optparse
+from typing import Any, Dict, Tuple
+
+from pylint.config.option import _validate
+
+
+class UnsupportedAction(Exception):
+    """raised by set_option when it doesn't know what to do for an action"""
+
+
+class OptionsProviderMixIn:
+    """Mixin to provide options to an OptionsManager"""
+
+    # those attributes should be overridden
+    priority = -1
+    name = "default"
+    options = ()  # type: Tuple[Tuple[str, Dict[str, Any]], ...]
+    level = 0
+
+    def __init__(self):
+        self.config = optparse.Values()
+        self.load_defaults()
+
+    def load_defaults(self):
+        """initialize the provider using default values"""
+        for opt, optdict in self.options:
+            action = optdict.get("action")
+            if action != "callback":
+                # callback action have no default
+                if optdict is None:
+                    optdict = self.get_option_def(opt)
+                default = optdict.get("default")
+                self.set_option(opt, default, action, optdict)
+
+    def option_attrname(self, opt, optdict=None):
+        """get the config attribute corresponding to opt"""
+        if optdict is None:
+            optdict = self.get_option_def(opt)
+        return optdict.get("dest", opt.replace("-", "_"))
+
+    def option_value(self, opt):
+        """get the current value for the given option"""
+        return getattr(self.config, self.option_attrname(opt), None)
+
+    def set_option(self, optname, value, action=None, optdict=None):
+        """method called to set an option (registered in the options list)"""
+        if optdict is None:
+            optdict = self.get_option_def(optname)
+        if value is not None:
+            value = _validate(value, optdict, optname)
+        if action is None:
+            action = optdict.get("action", "store")
+        if action == "store":
+            setattr(self.config, self.option_attrname(optname, optdict), value)
+        elif action in ("store_true", "count"):
+            setattr(self.config, self.option_attrname(optname, optdict), 0)
+        elif action == "store_false":
+            setattr(self.config, self.option_attrname(optname, optdict), 1)
+        elif action == "append":
+            optname = self.option_attrname(optname, optdict)
+            _list = getattr(self.config, optname, None)
+            if _list is None:
+                if isinstance(value, (list, tuple)):
+                    _list = value
+                elif value is not None:
+                    _list = []
+                    _list.append(value)
+                setattr(self.config, optname, _list)
+            elif isinstance(_list, tuple):
+                setattr(self.config, optname, _list + (value,))
+            else:
+                _list.append(value)
+        elif action == "callback":
+            optdict["callback"](None, optname, value, None)
+        else:
+            raise UnsupportedAction(action)
+
+    def get_option_def(self, opt):
+        """return the dictionary defining an option given its name"""
+        assert self.options
+        for option in self.options:
+            if option[0] == opt:
+                return option[1]
+        raise optparse.OptionError(
+            "no such option %s in section %r" % (opt, self.name), opt
+        )
+
+    def options_by_section(self):
+        """return an iterator on options grouped by section
+
+        (section, [list of (optname, optdict, optvalue)])
+        """
+        sections = {}
+        for optname, optdict in self.options:
+            sections.setdefault(optdict.get("group"), []).append(
+                (optname, optdict, self.option_value(optname))
+            )
+        if None in sections:
+            yield None, sections.pop(None)
+        for section, options in sorted(sections.items()):
+            yield section.upper(), options
+
+    def options_and_values(self, options=None):
+        if options is None:
+            options = self.options
+        for optname, optdict in options:
+            yield (optname, optdict, self.option_value(optname))