1 files changed, 121 insertions, 0 deletions
diff --git a/discord/ext/commands/cooldowns.py b/discord/ext/commands/cooldowns.py
new file mode 100644
index 00000000..035ac809
--- /dev/null
+++ b/discord/ext/commands/cooldowns.py
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+# -*- coding: utf-8 -*-
+"""
+The MIT License (MIT)
+
+Copyright (c) 2015-2016 Rapptz
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+import enum
+import time
+
+__all__ = ['BucketType', 'Cooldown', 'CooldownMapping']
+
+class BucketType(enum.Enum):
+    default = 0
+    user    = 1
+    server  = 2
+    channel = 3
+
+class Cooldown:
+    __slots__ = ['rate', 'per', 'type', '_window', '_tokens', '_last']
+
+    def __init__(self, rate, per, type):
+        self.rate = int(rate)
+        self.per = float(per)
+        self.type = type
+        self._window = 0.0
+        self._tokens = self.rate
+
+        if not isinstance(self.type, BucketType):
+            raise TypeError('Cooldown type must be a BucketType')
+
+    def is_rate_limited(self):
+        current = time.time()
+        self._last = current
+
+        # first token used means that we start a new rate limit window
+        if self._tokens == self.rate:
+            self._window = current
+
+        # check if our window has passed and we can refresh our tokens
+        if current > self._window + self.per:
+            self._tokens = self.rate
+            self._window = current
+
+        # check if we're rate limited
+        if self._tokens == 0:
+            return self.per - (current - self._window)
+
+        # we're not so decrement our tokens
+        self._tokens -= 1
+
+        # see if we got rate limited due to this token change, and if
+        # so update the window to point to our current time frame
+        if self._tokens == 0:
+            self._window = current
+
+    def copy(self):
+        return Cooldown(self.rate, self.per, self.type)
+
+    def __repr__(self):
+        return '<Cooldown rate: {0.rate} per: {0.per} window: {0._window} tokens: {0._tokens}>'.format(self)
+
+class CooldownMapping:
+    def __init__(self, original):
+        self._cache = {}
+        self._cooldown = original
+
+    @property
+    def valid(self):
+        return self._cooldown is not None
+
+    def _bucket_key(self, ctx):
+        msg = ctx.message
+        bucket_type = self._cooldown.type
+        if bucket_type is BucketType.user:
+            return msg.author.id
+        elif bucket_type is BucketType.server:
+            return getattr(msg.server, 'id', msg.author.id)
+        elif bucket_type is BucketType.channel:
+            return msg.channel.id
+
+    def _verify_cache_integrity(self):
+        # we want to delete all cache objects that haven't been used
+        # in a cooldown window. e.g. if we have a  command that has a
+        # cooldown of 60s and it has not been used in 60s then that key should be deleted
+        current = time.time()
+        dead_keys = [k for k, v in self._cache.items() if current > v._last + v.per]
+        for k in dead_keys:
+            del self._cache[k]
+
+    def get_bucket(self, ctx):
+        if self._cooldown.type is BucketType.default:
+            return self._cooldown
+
+        self._verify_cache_integrity()
+        key = self._bucket_key(ctx)
+        if key not in self._cache:
+            bucket = self._cooldown.copy()
+            self._cache[key] = bucket
+        else:
+            bucket = self._cache[key]
+
+        return bucket