From a1955c3a00a8398dc27beacb92c4efcb1119c8d3 Mon Sep 17 00:00:00 2001
From: Konsta Vesterinen <konsta.vesterinen@gmail.com>
Date: Thu, 7 Mar 2013 11:09:49 +0200
Subject: [PATCH] Added SmartList, 0.3 release

---
 CHANGES.rst                  |  7 +++++++
 docs/index.rst               |  4 ++++
 setup.py                     |  2 +-
 sqlalchemy_utils/__init__.py | 33 ++++++++++++++++++++++++++++++++-
 tests.py                     | 28 ++++++++++++++++++++++++++--
 5 files changed, 70 insertions(+), 4 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index ac2dc79..86d52a6 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,13 @@ Changelog
 Here you can see the full list of changes between each SQLAlchemy-Utils release.
 
 
+
+0.3.0 (2013-03-01)
+^^^^^^^^^^^^^^^^^^
+
+- Added new collection class SmartList
+
+
 0.2.0 (2013-03-01)
 ^^^^^^^^^^^^^^^^^^
 
diff --git a/docs/index.rst b/docs/index.rst
index a477467..65f1d3c 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -6,12 +6,16 @@
 SQLAlchemy-Utils
 ================
 
+SQLAlchemy-Utils provides various utility classes and functions for SQLAlchemy.
+
 
 
 API Documentation
 -----------------
 
 .. module:: sqlalchemy_utils
+.. autoclass:: SmartList
+    :members:
 .. autofunction:: sort_query
 .. autofunction:: escape_like
 
diff --git a/setup.py b/setup.py
index 28ad7c7..ae9f16e 100644
--- a/setup.py
+++ b/setup.py
@@ -24,7 +24,7 @@ class PyTest(Command):
 
 setup(
     name='SQLAlchemy-Utils',
-    version='0.2',
+    version='0.3',
     url='https://github.com/kvesteri/sqlalchemy-utils',
     license='BSD',
     author='Konsta Vesterinen',
diff --git a/sqlalchemy_utils/__init__.py b/sqlalchemy_utils/__init__.py
index 432cea5..5d55d59 100644
--- a/sqlalchemy_utils/__init__.py
+++ b/sqlalchemy_utils/__init__.py
@@ -1,10 +1,41 @@
 from sqlalchemy.orm import defer
+from sqlalchemy.orm.collections import InstrumentedList
 from sqlalchemy.orm.mapper import Mapper
 from sqlalchemy.orm.query import _ColumnEntity
 from sqlalchemy.orm.properties import ColumnProperty
 from sqlalchemy.sql.expression import desc, asc
 
 
+class SmartList(InstrumentedList):
+    def has(self, attr):
+        """
+        Returns True if any member of this collection has given attribute
+        defined.
+
+        Example syntax:
+
+            >>> Category.articles.has('name')
+
+        :param attr: collection member attribute name
+        """
+        adapter = self._sa_adapter
+        owner_class = adapter.owner_state.class_
+        relation = getattr(owner_class, adapter._key).property
+        relation_class = relation.mapper.class_
+
+        if not hasattr(relation_class, attr):
+            raise AttributeError(
+                'Class %s does not have attribute named %s' %
+                (relation_class.__name__, attr)
+            )
+
+        for record in self:
+            if getattr(record, attr):
+                return True
+
+        return False
+
+
 def sort_query(query, sort):
     """
     Applies an sql ORDER BY for given query. This function can be easily used
@@ -16,7 +47,7 @@ def sort_query(query, sort):
         >>> from sqlalchemy import create_engine
         >>> from sqlalchemy.orm import sessionmaker
         >>> from sqlalchemy.ext.declarative import declarative_base
-        >>> from sqlalchemy_utils import escape_like, sort_query
+        >>> from sqlalchemy_utils import sort_query
         >>>
         >>>
         >>> engine = create_engine(
diff --git a/tests.py b/tests.py
index 20716ff..b21c109 100644
--- a/tests.py
+++ b/tests.py
@@ -1,10 +1,11 @@
+from pytest import raises
 import sqlalchemy as sa
 
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 from sqlalchemy.ext.declarative import declarative_base
 
-from sqlalchemy_utils import escape_like, sort_query
+from sqlalchemy_utils import escape_like, sort_query, SmartList
 
 
 engine = create_engine(
@@ -29,10 +30,33 @@ class Article(Base):
     category_id = sa.Column(sa.Integer, sa.ForeignKey(Category.id))
 
     category = sa.orm.relationship(
-        Category, primaryjoin=category_id == Category.id
+        Category,
+        primaryjoin=category_id == Category.id,
+        backref=sa.orm.backref(
+            'articles',
+            collection_class=SmartList
+        )
     )
 
 
+class TestSmartList(object):
+    def test_has_raises_error_for_unknown_attribute(self):
+        category = Category()
+        with raises(AttributeError):
+            category.articles.has('unknown_column')
+
+    def test_has_returns_true_if_member_has_attr_defined(self):
+        category = Category()
+        category.articles.append(Article())
+        category.articles.append(Article(name=u'some name'))
+        assert category.articles.has('name')
+
+    def test_has_returns_false_if_no_member_has_attr_defined(self):
+        category = Category()
+        category.articles.append(Article())
+        assert not category.articles.has('name')
+
+
 class TestEscapeLike(object):
     def test_escapes_wildcards(self):
         assert escape_like('_*%') == '*_***%'