Implement pop and popitem

Author: asvetlov

aiohttp/_multidict.pyx

@@ -292,13 +292,32 @@ cdef class MultiDict(_Base):
         self._add((key, default))
         return default
 
-    def pop(self, key, default=None):
+    def pop(self, key, default=_marker):
+        cdef int found
+        cdef object value
+        value = None
+        found = False
+        for i in range(len(self._items) - 1, -1, -1):
+            if self._items[i][0] == key:
+                value = self._items[i][1]
+                del self._items[i]
+                found = True
+        if not found:
+            if default is _marker:
+                raise KeyError(key)
+            else:
+                return default
+        else:
+            return value
+
         """Method not allowed."""
         raise NotImplementedError
 
     def popitem(self):
-        """Method not allowed."""
-        raise NotImplementedError
+        if self._items:
+            return self._items.pop(0)
+        else:
+            raise KeyError("empty multidict")
 
     def update(self, *args, **kw):
         """Method not allowed."""

aiohttp/multidict.py

@@ -240,13 +240,27 @@ def setdefault(self, key, default=None):
         self._items.append((key, default))
         return default
 
-    def pop(self, key, default=None):
-        """Method not allowed."""
-        raise NotImplementedError
+    def pop(self, key, default=_marker):
+        value = None
+        found = False
+        for i in range(len(self._items) - 1, -1, -1):
+            if self._items[i][0] == key:
+                value = self._items[i][1]
+                del self._items[i]
+                found = True
+        if not found:
+            if default is _marker:
+                raise KeyError(key)
+            else:
+                return default
+        else:
+            return value
 
     def popitem(self):
-        """Method not allowed."""
-        raise NotImplementedError
+        if self._items:
+            return self._items.pop(0)
+        else:
+            raise KeyError("empty multidict")
 
     def update(self, *args, **kw):
         """Method not allowed."""

docs/multidict.rst

@@ -162,6 +162,25 @@ MutableMultiDict
       View contains all values if *getall* is ``True`` (default) or
       only first key occurrences otherwise.
 
+   .. method:: pop(key[, default])
+
+      If *key* is in the dictionary, remove it and return its the
+      **first** value, else return *default*.
+
+      If *default* is not given and *key* is not in the dictionary, a
+      :exc:`KeyError` is raised.
+
+
+   .. method:: popitem()
+
+      Remove and retun an arbitrary ``(key, value)`` pair from the dictionary.
+
+      :meth:`popitem` is useful to destructively iterate over a
+      dictionary, as often used in set algorithms.
+
+      If the dictionary is empty, calling :meth:`popitem` raises a
+      :exc:`KeyError`.
+
    .. method:: setdefault(key[, default])
 
       If *key* is in the dictionary, return its the **first** value.

tests/test_multidict.py

@@ -442,13 +442,45 @@ def test_set_default(self):
         self.assertIn('otherkey', d)
         self.assertEqual('three', d['otherkey'])
 
-    def test_not_implemented_methods(self):
+    def test_popitem(self):
         d = self.make_dict()
+        d.add('key', 'val1')
+        d.add('key', 'val2')
 
-        with self.assertRaises(NotImplementedError):
-            d.pop('foo')
-        with self.assertRaises(NotImplementedError):
+        self.assertEqual(('key', 'val1'), d.popitem())
+        self.assertEqual([('key', 'val2')], list(d.items()))
+
+    def test_popitem_empty_multidict(self):
+        d = self.make_dict()
+
+        with self.assertRaises(KeyError):
             d.popitem()
+
+    def test_pop(self):
+        d = self.make_dict()
+        d.add('key', 'val1')
+        d.add('key', 'val2')
+
+        self.assertEqual('val1', d.pop('key'))
+        self.assertFalse(d)
+
+    def test_pop_default(self):
+        d = self.make_dict(other='val')
+
+        self.assertEqual('default', d.pop('key', 'default'))
+        self.assertIn('other', d)
+
+    def test_pop_raises(self):
+        d = self.make_dict(other='val')
+
+        with self.assertRaises(KeyError):
+            d.pop('key')
+
+        self.assertIn('other', d)
+
+    def test_not_implemented_methods(self):
+        d = self.make_dict()
+
         with self.assertRaises(NotImplementedError):
             d.update(bar='baz')