Improve performance of value -> enum by about 5x.

3 files changed, 57 insertions, 4 deletions

diff --git a/discord/audit_logs.py b/discord/audit_logs.py
index faf05f20..49a5bb5a 100644
--- a/discord/audit_logs.py
+++ b/discord/audit_logs.py
@@ -216,7 +216,7 @@ class AuditLogEntry:
         self._from_data(data)
 
     def _from_data(self, data):
-        self.action = enums.AuditLogAction(data['action_type'])
+        self.action = enums.try_enum(enums.AuditLogAction, data['action_type'])
         self.id = int(data['id'])
 
         # this key is technically not usually present
diff --git a/discord/enums.py b/discord/enums.py
index ff5266fa..4c59dbf9 100644
--- a/discord/enums.py
+++ b/discord/enums.py
@@ -32,6 +32,20 @@ __all__ = ['ChannelType', 'MessageType', 'VoiceRegion', 'SpeakingState',
            'UserFlags', 'ActivityType', 'HypeSquadHouse', 'NotificationLevel',
            'PremiumType', 'UserContentFilter', 'FriendFlags', 'Theme']
 
+def fast_lookup(cls):
+    # NOTE: implies hashable
+    try:
+        lookup = cls._value2member_map_
+    except AttributeError:
+        lookup = {
+            member.value: member
+            for member in cls.__members__
+        }
+    finally:
+        cls.__fast_value_lookup__ = lookup
+        return cls
+
+@fast_lookup
 class ChannelType(Enum):
     text     = 0
     private  = 1
@@ -44,6 +58,7 @@ class ChannelType(Enum):
     def __str__(self):
         return self.name
 
+@fast_lookup
 class MessageType(Enum):
     default             = 0
     recipient_add       = 1
@@ -54,6 +69,7 @@ class MessageType(Enum):
     pins_add            = 6
     new_member          = 7
 
+@fast_lookup
 class VoiceRegion(Enum):
     us_west       = 'us-west'
     us_east       = 'us-east'
@@ -78,6 +94,7 @@ class VoiceRegion(Enum):
     def __str__(self):
         return self.value
 
+@fast_lookup
 class SpeakingState(Enum):
     none       = 0
     voice      = 1
@@ -90,6 +107,7 @@ class SpeakingState(Enum):
     def __int__(self):
         return self.value
 
+@fast_lookup
 class VerificationLevel(Enum):
     none              = 0
     low               = 1
@@ -102,6 +120,7 @@ class VerificationLevel(Enum):
     def __str__(self):
         return self.name
 
+@fast_lookup
 class ContentFilter(Enum):
     disabled    = 0
     no_role     = 1
@@ -110,11 +129,13 @@ class ContentFilter(Enum):
     def __str__(self):
         return self.name
 
+@fast_lookup
 class UserContentFilter(Enum):
     disabled    = 0
     friends     = 1
     all_messages = 2
 
+@fast_lookup
 class FriendFlags(Enum):
     noone = 0
     mutual_guilds = 1
@@ -122,10 +143,12 @@ class FriendFlags(Enum):
     guild_and_friends = 3
     everyone = 4
 
+@fast_lookup
 class Theme(Enum):
     light = 'light'
     dark = 'dark'
 
+@fast_lookup
 class Status(Enum):
     online = 'online'
     offline = 'offline'
@@ -137,6 +160,7 @@ class Status(Enum):
     def __str__(self):
         return self.value
 
+@fast_lookup
 class DefaultAvatar(Enum):
     blurple = 0
     grey    = 1
@@ -148,21 +172,25 @@ class DefaultAvatar(Enum):
     def __str__(self):
         return self.name
 
+@fast_lookup
 class RelationshipType(Enum):
     friend           = 1
     blocked          = 2
     incoming_request = 3
     outgoing_request = 4
 
+@fast_lookup
 class NotificationLevel(Enum):
     all_messages  = 0
     only_mentions = 1
 
+@fast_lookup
 class AuditLogActionCategory(Enum):
     create = 1
     delete = 2
     update = 3
 
+@fast_lookup
 class AuditLogAction(Enum):
     guild_update             = 1
     channel_create           = 10
@@ -245,6 +273,7 @@ class AuditLogAction(Enum):
         elif v < 80:
             return 'message'
 
+@fast_lookup
 class UserFlags(Enum):
     staff = 1
     partner = 2
@@ -255,6 +284,7 @@ class UserFlags(Enum):
     hypesquad_balance = 256
     early_supporter = 512
 
+@fast_lookup
 class ActivityType(Enum):
     unknown = -1
     playing = 0
@@ -262,11 +292,13 @@ class ActivityType(Enum):
     listening = 2
     watching = 3
 
+@fast_lookup
 class HypeSquadHouse(Enum):
     bravery = 1
     brilliance = 2
     balance = 3
 
+@fast_lookup
 class PremiumType(Enum):
     nitro_classic = 1
     nitro = 2
@@ -276,7 +308,28 @@ def try_enum(cls, val):
 
     If it fails it returns the value instead.
     """
+
+    # For some ungodly reason, `cls(x)` is *really* slow
+    # For most use cases it's about 750ns per call
+    # Internally this is dispatched like follows:
+    # cls(x)
+    # cls.__new__(cls, x)
+    # cls._value2member_map[x]
+    # if above fails ^
+    # find it in cls._member_map.items()
+
+    # Accessing the _value2member_map directly gives the biggest
+    # boost to performance, from 750ns to 130ns
+
+    # Now, the weird thing is that regular dict access is approx 31ns
+    # So there's a slowdown in the attribute access somewhere in the
+    # __getattr__ chain that I can't do much about
+
+    # Since this relies on internals the enums have an internal shim
+    # decorator that defines an alias for my own purposes or creates
+    # it for me under __fast_value_lookup__
+
     try:
-        return cls(val)
-    except ValueError:
+        return cls.__fast_value_lookup__[val]
+    except (KeyError, AttributeError):
         return val
diff --git a/discord/user.py b/discord/user.py
index 2b0b5263..b1d34868 100644
--- a/discord/user.py
+++ b/discord/user.py
@@ -164,7 +164,7 @@ class BaseUser(_BaseUser):
     @property
     def default_avatar(self):
         """Returns the default avatar for a given user. This is calculated by the user's discriminator"""
-        return DefaultAvatar(int(self.discriminator) % len(DefaultAvatar))
+        return try_enum(DefaultAvatar, int(self.discriminator) % len(DefaultAvatar))
 
     @property
     def default_avatar_url(self):