Bare bones of a notification system

.gitignore

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+.cache/*
+.tox/*
+*.pyc
+*.sw*
+*.egg-info

example.py

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+from flake8 import _trie as trie
+
+
+tree = trie.Trie()
+for i in range(5):
+    tree.add('E103', 'E103-listener-{0}'.format(i))
+    j = i + 1
+    tree.add('E1{0}3'.format(j), 'E1{0}3-listener'.format(j))
+for i in range(10):
+    tree.add('W1{0:02d}'.format(i), 'W1{0:02d}-listener'.format(i))

flake8/__init__.py

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+__version__ = '3.0.0a1'

flake8/_trie.py

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+"""Independent implementation of a Trie tree."""
+
+__all__ = ('Trie', 'TrieNode')
+
+
+def _iterate_stringlike_objects(string):
+    for i in range(len(string)):
+        yield string[i:i+1]
+
+
+class Trie(object):
+    """The object that manages the trie nodes."""
+
+    def __init__(self):
+        """Initialize an empty trie."""
+        self.root = TrieNode(None, None)
+
+    def add(self, path, node_data):
+        """Add the node data to the path described."""
+        node = self.root
+        for prefix in _iterate_stringlike_objects(path):
+            child = node.find_prefix(prefix)
+            if child is None:
+                child = node.add_child(prefix, [])
+            node = child
+        node.data.append(node_data)
+
+    def find(self, path):
+        """Find a node based on the path provided."""
+        node = self.root
+        for prefix in _iterate_stringlike_objects(path):
+            child = node.find_prefix(prefix)
+            if child is None:
+                return None
+            node = child
+        return node
+
+
+class TrieNode(object):
+    """The majority of the implementation details of a Trie."""
+
+    def __init__(self, prefix, data, children=None):
+        """Initialize a TrieNode with data and children."""
+        self.children = children or {}
+        self.data = data
+        self.prefix = prefix
+
+    def __repr__(self):
+        """Generate an easy to read representation of the node."""
+        return 'TrieNode(prefix={0}, data={1}, children={2})'.format(
+            self.prefix, self.data, dict(self.children)
+        )
+
+    def find_prefix(self, prefix):
+        """Find the prefix in the children of this node.
+
+        :returns: A child matching the prefix or None.
+        :rtype: :class:`~TrieNode` or None
+        """
+        return self.children.get(prefix, None)
+
+    def add_child(self, prefix, data, children=None):
+        """Create and add a new child node.
+
+        :returns: The newly created node
+        :rtype: :class:`~TrieNode`
+        """
+        new_node = TrieNode(prefix, data, children)
+        self.children[prefix] = new_node
+        return new_node
+
+    def traverse(self):
+        """Traverse children of this node in order."""
+        raise NotImplementedError()

flake8/notifier.py

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+from flake8 import _trie
+
+
+class Notifier(object):
+    def __init__(self):
+        self.listeners = _trie.Trie()
+
+    def listeners_for(self, error_code):
+        node = self.listeners.find(error_code)
+        for listener in node.data:
+            yield listener
+        if node.children:
+            for child in node.traverse():
+                for listener in child.data:
+                    yield listener
+
+    def notify(self, error_code, *args, **kwargs):
+        for listener in self.listeners_for(error_code):
+            listener.notify(*args, **kwargs)
+
+    def register_listener(self, error_code, listener):
+        self.listeners.add(error_code, listener)

setup.py

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+# -*- coding: utf-8 -*-
+from __future__ import with_statement
+from setuptools import setup
+try:
+    # Work around a traceback with Nose on Python 2.6
+    # http://bugs.python.org/issue15881#msg170215
+    __import__('multiprocessing')
+except ImportError:
+    pass
+
+try:
+    # Use https://docs.python.org/3/library/unittest.mock.html
+    from unittest import mock
+except ImportError:
+    # < Python 3.3
+    mock = None
+
+
+tests_require = ['nose']
+if mock is None:
+    tests_require += ['mock']
+
+
+def get_version(fname='flake8/__init__.py'):
+    with open(fname) as f:
+        for line in f:
+            if line.startswith('__version__'):
+                return eval(line.split('=')[-1])
+
+
+def get_long_description():
+    descr = []
+    for fname in ('README.rst', 'CHANGES.rst'):
+        with open(fname) as f:
+            descr.append(f.read())
+    return '\n\n'.join(descr)
+
+
+setup(
+    name="flake8",
+    license="MIT",
+    version=get_version(),
+    description="the modular source code checker: pep8, pyflakes and co",
+    # long_description=get_long_description(),
+    author="Tarek Ziade",
+    author_email="tarek@ziade.org",
+    maintainer="Ian Cordasco",
+    maintainer_email="graffatcolmingov@gmail.com",
+    url="https://gitlab.com/pycqa/flake8",
+    packages=["flake8"],
+    install_requires=[
+        "pyflakes >= 0.8.1, < 1.1",
+        "pep8 >= 1.5.7, != 1.6.0, != 1.6.1, != 1.6.2",
+        "mccabe >= 0.2.1, < 0.4",
+    ],
+    entry_points={
+        'distutils.commands': ['flake8 = flake8.main:Flake8Command'],
+        'console_scripts': ['flake8 = flake8.main:main'],
+        'flake8.extension': [
+            'F = flake8._pyflakes:FlakesChecker',
+        ],
+    },
+    classifiers=[
+        "Environment :: Console",
+        "Intended Audience :: Developers",
+        "License :: OSI Approved :: MIT License",
+        "Programming Language :: Python",
+        "Programming Language :: Python :: 2",
+        "Programming Language :: Python :: 3",
+        "Topic :: Software Development :: Libraries :: Python Modules",
+        "Topic :: Software Development :: Quality Assurance",
+    ],
+    tests_require=tests_require,
+    test_suite='nose.collector',
+)

tests/test_trie.py

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+from flake8 import _trie as trie
+
+
+def test_build_tree():
+    tree = trie.Trie()
+    for i in range(5):
+        tree.add('E103', 'E103-listener-{0}'.format(i))
+        j = i + 1
+        tree.add('E1{0}3'.format(j), 'E1{0}3-listener'.format(j))
+    for i in range(10):
+        tree.add('W1{0:02d}'.format(i), 'W1{0:02d}-listener'.format(i))
+
+    assert tree.find('E103') is not None
+    assert tree.find('E200') is None

tox.ini

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+[tox]
+envlist = py26,py27,py32,py33,py34,py35
+
+[testenv]
+deps =
+    pytest
+commands =
+    py.test