Add src directory.

1 files changed, 31 insertions, 0 deletions

diff --git a/src/cachetools/fifo.py b/src/cachetools/fifo.py
new file mode 100644
index 0000000..e7c377e
--- /dev/null
+++ b/src/cachetools/fifo.py
@@ -0,0 +1,31 @@
+import collections
+
+from .cache import Cache
+
+
+class FIFOCache(Cache):
+    """First In First Out (FIFO) cache implementation."""
+
+    def __init__(self, maxsize, getsizeof=None):
+        Cache.__init__(self, maxsize, getsizeof)
+        self.__order = collections.OrderedDict()
+
+    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
+        cache_setitem(self, key, value)
+        try:
+            self.__order.move_to_end(key)
+        except KeyError:
+            self.__order[key] = None
+
+    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
+        cache_delitem(self, key)
+        del self.__order[key]
+
+    def popitem(self):
+        """Remove and return the `(key, value)` pair first inserted."""
+        try:
+            key = next(iter(self.__order))
+        except StopIteration:
+            raise KeyError("%s is empty" % type(self).__name__) from None
+        else:
+            return (key, self.pop(key))