Add configuration provider

setup.py

@@ -51,6 +51,10 @@ setup(name='dependency-injector',
                     ['src/dependency_injector/providers/base.c'],
                     define_macros=defined_macros,
                     extra_compile_args=['-O2']),
+          Extension('dependency_injector.providers.configuration',
+                    ['src/dependency_injector/providers/configuration.c'],
+                    define_macros=defined_macros,
+                    extra_compile_args=['-O2']),
           Extension('dependency_injector.providers.callables',
                     ['src/dependency_injector/providers/callables.c'],
                     define_macros=defined_macros,

src/dependency_injector/providers/__init__.py

@@ -7,6 +7,9 @@ from .base import (
     ExternalDependency,
     OverridingContext,
 )
+from .configuration import (
+    Configuration,
+)
 from .callables import (
     Callable,
     DelegatedCallable,
@@ -48,6 +51,8 @@ __all__ = (
     'ExternalDependency',
     'OverridingContext',
 
+    'Configuration',
+
     'Callable',
     'DelegatedCallable',
 

src/dependency_injector/providers/configuration.pxd

@@ -0,0 +1,19 @@
+"""Dependency injector configuration providers.
+
+Powered by Cython.
+"""
+
+from .base cimport (
+    Provider,
+)
+
+
+cdef class Configuration(Provider):
+    cdef str __name
+    cdef object __value
+    cdef dict __children
+
+    cpdef str get_name(self)
+    cpdef object update(self, object value)
+    cpdef object _provide(self, tuple args, dict kwargs)
+    cpdef str _get_child_name(self, str child_name)

src/dependency_injector/providers/configuration.pyx

@@ -0,0 +1,99 @@
+"""Dependency injector configuration providers.
+
+Powered by Cython.
+"""
+
+from .base cimport (
+    Provider,
+)
+from .utils cimport (
+    represent_provider,
+    deepcopy,
+)
+
+
+cdef class Configuration(Provider):
+    """Configuration provider."""
+
+    def __init__(self, name):
+        """Initializer."""
+        self.__name = name
+        self.__value = None
+        self.__children = dict()
+        super(Configuration, self).__init__()
+
+    def __deepcopy__(self, memo):
+        """Create and return full copy of provider."""
+        copied = memo.get(id(self))
+        if copied is not None:
+            return copied
+
+        copied = self.__class__(self.__name)
+        copied.update(deepcopy(self.__value))
+
+        for overriding_provider in self.overridden:
+            copied.override(deepcopy(overriding_provider, memo))
+
+        return copied
+
+    def __str__(self):
+        """Return string representation of provider.
+
+        :rtype: str
+        """
+        return represent_provider(provider=self, provides=self.__name)
+
+    def __getattr__(self, name):
+        """Return child configuration provider."""
+        cdef Configuration child_provider
+        cdef object value
+
+        child_provider = self.__children.get(name)
+
+        if child_provider is None:
+            child_provider = self.__class__(self._get_child_name(name))
+
+            if isinstance(self.__value, dict):
+                child_provider.update(self.__value.get(name))
+
+            self.__children[name] = child_provider
+
+        return child_provider
+
+    cpdef str get_name(self):
+        """Name of configuration unit."""
+        return self.__name
+
+    cpdef object update(self, value):
+        """Set configuration options."""
+        cdef Configuration child_provider
+        cdef object child_value
+
+        self.__value = value
+
+        if not isinstance(self.__value, dict):
+            return
+
+        for name in self.__value:
+            child_provider = self.__children.get(name)
+
+            if child_provider is None:
+                continue
+
+            child_provider.update(self.__value.get(name))
+
+    cpdef object _provide(self, tuple args, dict kwargs):
+        """Return result of provided callable's call."""
+        return self.__value
+
+    cpdef str _get_child_name(self, str child_name):
+        cdef str child_full_name
+
+        child_full_name = ''
+
+        if self.__name:
+            child_full_name += self.__name + '.'
+
+        child_full_name += child_name
+
+        return child_full_name

tests/unit/providers/test_configuration.py

@@ -0,0 +1,96 @@
+"""Dependency injector config providers unit tests."""
+
+import unittest2 as unittest
+
+from dependency_injector import providers
+
+
+class ConfigTests(unittest.TestCase):
+
+    def setUp(self):
+        self.config = providers.Configuration(name='config')
+
+    def tearDown(self):
+        del self.config
+
+    def test_providers_are_providers(self):
+        self.assertTrue(providers.is_provider(self.config.a))
+        self.assertTrue(providers.is_provider(self.config.a.b))
+        self.assertTrue(providers.is_provider(self.config.a.b.c))
+        self.assertTrue(providers.is_provider(self.config.a.b.d))
+
+    def test_providers_are_not_delegates(self):
+        self.assertFalse(providers.is_delegated(self.config.a))
+        self.assertFalse(providers.is_delegated(self.config.a.b))
+        self.assertFalse(providers.is_delegated(self.config.a.b.c))
+        self.assertFalse(providers.is_delegated(self.config.a.b.d))
+
+    def test_providers_identity(self):
+        self.assertIs(self.config.a, self.config.a)
+        self.assertIs(self.config.a.b, self.config.a.b)
+        self.assertIs(self.config.a.b.c, self.config.a.b.c)
+        self.assertIs(self.config.a.b.d, self.config.a.b.d)
+
+    def test_get_name(self):
+        self.assertEqual(self.config.a.b.c.get_name(), 'config.a.b.c')
+
+    def test_providers_value_setting(self):
+        a = self.config.a
+        ab = self.config.a.b
+        abc = self.config.a.b.c
+        abd = self.config.a.b.d
+
+        self.config.update({'a': {'b': {'c': 1, 'd': 2}}})
+
+        self.assertEqual(a(), {'b': {'c': 1, 'd': 2}})
+        self.assertEqual(ab(), {'c': 1, 'd': 2})
+        self.assertEqual(abc(), 1)
+        self.assertEqual(abd(), 2)
+
+    def test_value_of_undefined_option(self):
+        self.assertIsNone(self.config.a())
+
+    def test_deepcopy(self):
+        provider = providers.Configuration('config')
+        provider_copy = providers.deepcopy(provider)
+
+        self.assertIsNot(provider, provider_copy)
+        self.assertIsInstance(provider, providers.Configuration)
+
+    def test_deepcopy_from_memo(self):
+        provider = providers.Configuration('config')
+        provider_copy_memo = providers.Configuration('config')
+
+        provider_copy = providers.deepcopy(
+            provider, memo={id(provider): provider_copy_memo})
+
+        self.assertIs(provider_copy, provider_copy_memo)
+
+    def test_deepcopy_overridden(self):
+        provider = providers.Configuration('config')
+        object_provider = providers.Object(object())
+
+        provider.override(object_provider)
+
+        provider_copy = providers.deepcopy(provider)
+        object_provider_copy = provider_copy.overridden[0]
+
+        self.assertIsNot(provider, provider_copy)
+        self.assertIsInstance(provider, providers.Configuration)
+
+        self.assertIsNot(object_provider, object_provider_copy)
+        self.assertIsInstance(object_provider_copy, providers.Object)
+
+    def test_repr(self):
+        self.assertEqual(repr(self.config),
+                         '<dependency_injector.providers.configuration.'
+                         'Configuration({0}) at {1}>'.format(
+                             repr('config'),
+                             hex(id(self.config))))
+
+    def test_repr_child(self):
+        self.assertEqual(repr(self.config.a.b.c),
+                         '<dependency_injector.providers.configuration.'
+                         'Configuration({0}) at {1}>'.format(
+                             repr('config.a.b.c'),
+                             hex(id(self.config.a.b.c))))