1 files changed, 50 insertions, 0 deletions
diff --git a/src/Cache.py b/src/Cache.py
new file mode 100644
index 00000000..4d7c8def
--- /dev/null
+++ b/src/Cache.py
@@ -0,0 +1,50 @@
+import time, uuid
+
+class Cache(object):
+    def __init__(self):
+        self._items = {}
+        self._item_to_id = {}
+
+    def cache(self, item):
+        return self._cache(item, None)
+    def temporary_cache(self, item, timeout):
+        return self._cache(item, timeout)
+    def _cache(self, item, timeout):
+        id = str(uuid.uuid4())
+        self._items[id] = [item, time.monotonic()+timeout]
+        self._item_to_id[item] = id
+        return id
+
+    def next_expiration(self):
+        expirations = [self._items[id][1] for id in self._items]
+        expirations = list(filter(None, expirations))
+        if not expirations:
+            return None
+        expirations = [e-time.monotonic() for e in expirations]
+        return max(min(expirations), 0)
+
+    def expire(self):
+        now = time.monotonic()
+        expired = []
+        for id in self._items:
+            item, expiration = self._items[id]
+            if expiration and expiration <= now:
+                expired.append(id)
+        for id in expired:
+            del self._items[id]
+            del self._item_to_id[item]
+
+    def has_item(self, item):
+        return item in self._item_to_id
+
+    def get(self, id):
+        item, expiration = self._items[id]
+        return item
+
+    def get_expiration(self, item):
+        id = self._item_to_id[item]
+        item, expiration = self._items[id]
+        return expiration
+    def until_expiration(self, item):
+        expiration = self.get_expiration(item)
+        return expiration-time.monotonic()