Several memory and performance improvements

src/Discord.Net/API/Common/GuildMember.cs

@@ -12,7 +12,7 @@ namespace Discord.API
         [JsonProperty("roles")]
         public ulong[] Roles { get; set; }
         [JsonProperty("joined_at")]
-        public DateTime JoinedAt { get; set; }
+        public DateTimeOffset JoinedAt { get; set; }
         [JsonProperty("deaf")]
         public bool Deaf { get; set; }
         [JsonProperty("mute")]

src/Discord.Net/API/Common/Integration.cs

@@ -26,6 +26,6 @@ namespace Discord.API
         [JsonProperty("account")]
         public IntegrationAccount Account { get; set; }
         [JsonProperty("synced_at")]
-        public DateTime SyncedAt { get; set; }
+        public DateTimeOffset SyncedAt { get; set; }
     }
 }

src/Discord.Net/API/Common/InviteMetadata.cs

@@ -16,7 +16,7 @@ namespace Discord.API
         [JsonProperty("temporary")]
         public bool Temporary { get; set; }
         [JsonProperty("created_at")]
-        public DateTime CreatedAt { get; set; }
+        public DateTimeOffset CreatedAt { get; set; }
         [JsonProperty("revoked")]
         public bool Revoked { get; set; }
     }

src/Discord.Net/API/Common/Message.cs

@@ -14,9 +14,9 @@ namespace Discord.API
         [JsonProperty("content")]
         public Optional<string> Content { get; set; }
         [JsonProperty("timestamp")]
-        public Optional<DateTime> Timestamp { get; set; }
+        public Optional<DateTimeOffset> Timestamp { get; set; }
         [JsonProperty("edited_timestamp")]
-        public Optional<DateTime?> EditedTimestamp { get; set; }
+        public Optional<DateTimeOffset?> EditedTimestamp { get; set; }
         [JsonProperty("tts")]
         public Optional<bool> IsTextToSpeech { get; set; }
         [JsonProperty("mention_everyone")]

src/Discord.Net/API/Gateway/ExtendedGuild.cs

@@ -19,6 +19,6 @@ namespace Discord.API.Gateway
         [JsonProperty("channels")]
         public Channel[] Channels { get; set; }
         [JsonProperty("joined_at")]
-        public DateTime JoinedAt { get; set; }
+        public DateTimeOffset JoinedAt { get; set; }
     }
 }

src/Discord.Net/DiscordSocketClient.cs

@@ -10,7 +10,6 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -38,6 +37,7 @@ namespace Discord
         public event Func<ISelfUser, ISelfUser, Task> CurrentUserUpdated;
         public event Func<IChannel, IUser, Task> UserIsTyping;
         public event Func<int, Task> LatencyUpdated;
+        //TODO: Add PresenceUpdated? VoiceStateUpdated?
 
         private readonly ConcurrentQueue<ulong> _largeGuilds;
         private readonly Logger _gatewayLogger;
@@ -50,6 +50,7 @@ namespace Discord
         private readonly bool _enablePreUpdateEvents;
         private readonly int _largeThreshold;
         private readonly int _totalShards;
+        private ConcurrentHashSet<ulong> _dmChannels;
         private string _sessionId;
         private int _lastSeq;
         private ImmutableDictionary<string, VoiceRegion> _voiceRegions;
@@ -71,20 +72,14 @@ namespace Discord
         internal DataStore DataStore { get; private set; }
 
         internal CachedSelfUser CurrentUser => _currentUser as CachedSelfUser;
-        internal IReadOnlyCollection<CachedGuild> Guilds
-        {
-            get
-            {
-                var guilds = DataStore.Guilds;
-                return guilds.ToReadOnlyCollection(guilds);
-            }
-        }
+        internal IReadOnlyCollection<CachedGuild> Guilds => DataStore.Guilds;
         internal IReadOnlyCollection<CachedDMChannel> DMChannels
         {
             get
             {
-                var users = DataStore.Users;
-                return users.Select(x => x.DMChannel).Where(x => x != null).ToReadOnlyCollection(users);
+                var dmChannels = _dmChannels;
+                var store = DataStore;
+                return dmChannels.Select(x => store.GetChannel(x) as CachedDMChannel).Where(x => x != null).ToReadOnlyCollection(dmChannels);
             }
         }
         internal IReadOnlyCollection<VoiceRegion> VoiceRegions => _voiceRegions.ToReadOnlyCollection();
@@ -136,6 +131,7 @@ namespace Discord
 
             _voiceRegions = ImmutableDictionary.Create<string, VoiceRegion>();
             _largeGuilds = new ConcurrentQueue<ulong>();
+            _dmChannels = new ConcurrentHashSet<ulong>();
         }
 
         protected override async Task OnLoginAsync()
@@ -305,11 +301,16 @@ namespace Discord
         {
             return Task.FromResult<IChannel>(DataStore.GetChannel(id));
         }
-        internal CachedDMChannel AddDMChannel(API.Channel model, DataStore dataStore)
+        public override Task<IReadOnlyCollection<IDMChannel>> GetDMChannelsAsync()
+        {
+            return Task.FromResult<IReadOnlyCollection<IDMChannel>>(DMChannels);
+        }
+        internal CachedDMChannel AddDMChannel(API.Channel model, DataStore dataStore, ConcurrentHashSet<ulong> dmChannels)
         {
             var recipient = GetOrAddUser(model.Recipient.Value, dataStore);
             var channel = recipient.AddDMChannel(model);
             dataStore.AddChannel(channel);
+            dmChannels.TryAdd(model.Id);
             return channel;
         }
         internal CachedDMChannel RemoveDMChannel(ulong id)
@@ -317,6 +318,7 @@ namespace Discord
             var dmChannel = DataStore.RemoveChannel(id) as CachedDMChannel;            
             var recipient = dmChannel.Recipient;
             recipient.RemoveDMChannel(id);
+            _dmChannels.TryRemove(id);
             return dmChannel;
         }
 
@@ -455,6 +457,7 @@ namespace Discord
                                     
                                     var data = (payload as JToken).ToObject<ReadyEvent>(_serializer);
                                     var dataStore = _dataStoreProvider(ShardId, _totalShards, data.Guilds.Length, data.PrivateChannels.Length);
+                                    var dmChannels = new ConcurrentHashSet<ulong>();
 
                                     var currentUser = new CachedSelfUser(this, data.User);
                                     //dataStore.GetOrAddUser(data.User.Id, _ => currentUser);
@@ -462,10 +465,11 @@ namespace Discord
                                     for (int i = 0; i < data.Guilds.Length; i++)
                                         AddGuild(data.Guilds[i], dataStore);
                                     for (int i = 0; i < data.PrivateChannels.Length; i++)
-                                        AddDMChannel(data.PrivateChannels[i], dataStore);
+                                        AddDMChannel(data.PrivateChannels[i], dataStore, dmChannels);
 
                                     _sessionId = data.SessionId;
                                     _currentUser = currentUser;
+                                    _dmChannels = dmChannels;
                                     DataStore = dataStore;
 
                                     await Ready.RaiseAsync().ConfigureAwait(false);
@@ -577,7 +581,7 @@ namespace Discord
                                         }
                                     }
                                     else
-                                        channel = AddDMChannel(data, DataStore);
+                                        channel = AddDMChannel(data, DataStore, _dmChannels);
                                     if (channel != null)
                                         await ChannelCreated.RaiseAsync(channel).ConfigureAwait(false);
                                 }

src/Discord.Net/Entities/Guilds/GuildIntegration.cs

@@ -9,13 +9,14 @@ namespace Discord
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     internal class GuildIntegration : Entity<ulong>, IGuildIntegration
     {
+        private long _syncedAtTicks;
+
         public string Name { get; private set; }
         public string Type { get; private set; }
         public bool IsEnabled { get; private set; }
         public bool IsSyncing { get; private set; }
         public ulong ExpireBehavior { get; private set; }
         public ulong ExpireGracePeriod { get; private set; }
-        public DateTime SyncedAt { get; private set; }
 
         public Guild Guild { get; private set; }
         public Role Role { get; private set; }
@@ -23,6 +24,7 @@ namespace Discord
         public IntegrationAccount Account { get; private set; }
 
         public override DiscordClient Discord => Guild.Discord;
+        public DateTimeOffset SyncedAt => DateTimeUtils.FromTicks(_syncedAtTicks);
 
         public GuildIntegration(Guild guild, Model model)
             : base(model.Id)
@@ -41,7 +43,7 @@ namespace Discord
             IsSyncing = model.Syncing;
             ExpireBehavior = model.ExpireBehavior;
             ExpireGracePeriod = model.ExpireGracePeriod;
-            SyncedAt = model.SyncedAt;
+            _syncedAtTicks = model.SyncedAt.UtcTicks;
 
             Role = Guild.GetRole(model.RoleId);
             User = new User(Discord, model.User);

src/Discord.Net/Entities/Guilds/IGuildIntegration.cs

@@ -2,6 +2,7 @@
 
 namespace Discord
 {
+    //TODO: Add docstrings
     public interface IGuildIntegration
     {
         ulong Id { get; }
@@ -11,7 +12,7 @@ namespace Discord
         bool IsSyncing { get; }
         ulong ExpireBehavior { get; }
         ulong ExpireGracePeriod { get; }
-        DateTime SyncedAt { get; }
+        DateTimeOffset SyncedAt { get; }
         IntegrationAccount Account { get; }
 
         IGuild Guild { get; }

src/Discord.Net/Entities/ISnowflakeEntity.cs

@@ -5,6 +5,6 @@ namespace Discord
     public interface ISnowflakeEntity : IEntity<ulong>
     {
         /// <summary> Gets when this object was created. </summary>
-        DateTime CreatedAt { get; }
+        DateTimeOffset CreatedAt { get; }
     }
 }

src/Discord.Net/Entities/Invites/IInviteMetadata.cs

@@ -17,6 +17,6 @@ namespace Discord
         /// <summary> Gets the amount of times this invite has been used. </summary>
         int Uses { get; }
         /// <summary> Gets when this invite was created. </summary>
-        DateTime CreatedAt { get; }
+        DateTimeOffset CreatedAt { get; }
     }
 }

src/Discord.Net/Entities/Invites/InviteMetadata.cs

@@ -5,14 +5,17 @@ namespace Discord
 {
     internal class InviteMetadata : Invite, IInviteMetadata
     {
+        private long _createdAtTicks;
+
         public bool IsRevoked { get; private set; }
         public bool IsTemporary { get; private set; }
         public int? MaxAge { get; private set; }
         public int? MaxUses { get; private set; }
         public int Uses { get; private set; }
-        public DateTime CreatedAt { get; private set; }
         public IUser Inviter { get; private set; }
 
+        public DateTimeOffset CreatedAt => DateTimeUtils.FromTicks(_createdAtTicks);
+
         public InviteMetadata(DiscordClient client, Model model)
             : base(client, model)
         {
@@ -28,7 +31,7 @@ namespace Discord
             MaxAge = model.MaxAge != 0 ? model.MaxAge : (int?)null;
             MaxUses = model.MaxUses;
             Uses = model.Uses;
-            CreatedAt = model.CreatedAt;
+            _createdAtTicks = model.CreatedAt.UtcTicks;
         }
     }
 }

src/Discord.Net/Entities/Messages/IMessage.cs

@@ -8,7 +8,7 @@ namespace Discord
     public interface IMessage : IDeletable, ISnowflakeEntity, IUpdateable
     {
         /// <summary> Gets the time of this message's last edit, if any. </summary>
-        DateTime? EditedTimestamp { get; }
+        DateTimeOffset? EditedTimestamp { get; }
         /// <summary> Returns true if this message was sent as a text-to-speech message. </summary>
         bool IsTTS { get; }
         /// <summary> Returns the original, unprocessed text for this message. </summary>
@@ -16,7 +16,7 @@ namespace Discord
         /// <summary> Returns the text for this message after mention processing. </summary>
         string Text { get; }
         /// <summary> Gets the time this message was sent. </summary>
-        DateTime Timestamp { get; }
+        DateTimeOffset Timestamp { get; }
 
         /// <summary> Gets the channel this message was sent to. </summary>
         IMessageChannel Channel { get; }

src/Discord.Net/Entities/Messages/Message.cs

@@ -12,12 +12,12 @@ namespace Discord
     internal class Message : SnowflakeEntity, IMessage
     {
         private bool _isMentioningEveryone;
+        private long _timestampTicks;
+        private long? _editedTimestampTicks;
 
-        public DateTime? EditedTimestamp { get; private set; }
         public bool IsTTS { get; private set; }
         public string RawText { get; private set; }
         public string Text { get; private set; }
-        public DateTime Timestamp { get; private set; }
         
         public IMessageChannel Channel { get; }
         public IUser Author { get; }
@@ -29,6 +29,8 @@ namespace Discord
         public ImmutableArray<User> MentionedUsers { get; private set; }
 
         public override DiscordClient Discord => (Channel as Entity<ulong>).Discord;
+        public DateTimeOffset? EditedTimestamp => DateTimeUtils.FromTicks(_editedTimestampTicks);
+        public DateTimeOffset Timestamp => DateTimeUtils.FromTicks(_timestampTicks);
 
         public Message(IMessageChannel channel, IUser author, Model model)
             : base(model.Id)
@@ -56,9 +58,9 @@ namespace Discord
             if (model.IsTextToSpeech.IsSpecified)
                 IsTTS = model.IsTextToSpeech.Value;
             if (model.Timestamp.IsSpecified)
-                Timestamp = model.Timestamp.Value;
+                _timestampTicks = model.Timestamp.Value.UtcTicks;
             if (model.EditedTimestamp.IsSpecified)
-                EditedTimestamp = model.EditedTimestamp.Value;
+                _editedTimestampTicks = model.EditedTimestamp.Value?.UtcTicks;
             if (model.IsMentioningEveryone.IsSpecified)
                 _isMentioningEveryone = model.IsMentioningEveryone.Value;
             

src/Discord.Net/Entities/SnowflakeEntity.cs

@@ -5,7 +5,7 @@ namespace Discord
     internal abstract class SnowflakeEntity : Entity<ulong>, ISnowflakeEntity
     {
         //TODO: C#7 Candidate for Extension Property. Lets us remove this class.
-        public DateTime CreatedAt => DateTimeUtils.FromSnowflake(Id);
+        public DateTimeOffset CreatedAt => DateTimeUtils.FromSnowflake(Id);
 
         public SnowflakeEntity(ulong id)
             : base(id)

src/Discord.Net/Entities/Users/GuildUser.cs

@@ -14,9 +14,10 @@ namespace Discord
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     internal class GuildUser : IGuildUser, ISnowflakeEntity
     {
+        private long? _joinedAtTicks;
+
         public bool IsDeaf { get; private set; }
         public bool IsMute { get; private set; }
-        public DateTime? JoinedAt { get; private set; }
         public string Nickname { get; private set; }
         public GuildPermissions GuildPermissions { get; private set; }
 
@@ -26,7 +27,7 @@ namespace Discord
 
         public ulong Id => User.Id;
         public string AvatarUrl => User.AvatarUrl;
-        public DateTime CreatedAt => User.CreatedAt;
+        public DateTimeOffset CreatedAt => User.CreatedAt;
         public string Discriminator => User.Discriminator;
         public bool IsAttached => User.IsAttached;
         public bool IsBot => User.IsBot;
@@ -36,6 +37,7 @@ namespace Discord
         public virtual Game? Game => User.Game;
 
         public DiscordClient Discord => Guild.Discord;
+        public DateTimeOffset? JoinedAt => DateTimeUtils.FromTicks(_joinedAtTicks);
 
         public GuildUser(Guild guild, User user)
         {
@@ -62,7 +64,7 @@ namespace Discord
             //if (model.Mute.IsSpecified)
                 IsMute = model.Mute;
             //if (model.JoinedAt.IsSpecified)
-                JoinedAt = model.JoinedAt;
+                _joinedAtTicks = model.JoinedAt.UtcTicks;
             if (model.Nick.IsSpecified)
                 Nickname = model.Nick.Value;
 

src/Discord.Net/Entities/Users/IGuildUser.cs

@@ -13,7 +13,7 @@ namespace Discord
         /// <summary> Returns true if the guild has muted this user. </summary>
         bool IsMute { get; }
         /// <summary> Gets when this user joined this guild. </summary>
-        DateTime? JoinedAt { get; }
+        DateTimeOffset? JoinedAt { get; }
         /// <summary> Gets the nickname for this user. </summary>
         string Nickname { get; }
         /// <summary> Gets the guild-level permissions granted to this user by their roles. </summary>

src/Discord.Net/Entities/Users/User.cs

@@ -9,14 +9,15 @@ namespace Discord
     internal class User : SnowflakeEntity, IUser
     {
         private string _avatarId;
-        
-        public string Discriminator { get; private set; }
+        private ushort _discriminator;
+
         public bool IsBot { get; private set; }
         public string Username { get; private set; }
 
         public override DiscordClient Discord { get; }
 
         public string AvatarUrl => API.CDN.GetUserAvatarUrl(Id, _avatarId);
+        public string Discriminator => _discriminator.ToString("D4");
         public string Mention => MentionUtils.Mention(this, false);
         public string NicknameMention => MentionUtils.Mention(this, true);
         public virtual Game? Game => null;
@@ -33,7 +34,7 @@ namespace Discord
             if (source == UpdateSource.Rest && IsAttached) return;
 
             _avatarId = model.Avatar;
-            Discriminator = model.Discriminator;
+            _discriminator = ushort.Parse(model.Discriminator);
             IsBot = model.Bot;
             Username = model.Username;
         }

src/Discord.Net/Entities/WebSocket/CachedGuild.cs

@@ -32,7 +32,15 @@ namespace Discord
 
         public new DiscordSocketClient Discord => base.Discord as DiscordSocketClient;
         public CachedGuildUser CurrentUser => GetUser(Discord.CurrentUser.Id);
-        public IReadOnlyCollection<ICachedGuildChannel> Channels => _channels.Select(x => GetChannel(x)).ToReadOnlyCollection(_channels);
+        public IReadOnlyCollection<ICachedGuildChannel> Channels
+        {
+            get
+            {
+                var channels = _channels;
+                var store = Discord.DataStore;
+                return channels.Select(x => store.GetChannel(x) as ICachedGuildChannel).Where(x => x != null).ToReadOnlyCollection(channels);
+            }
+        }
         public IReadOnlyCollection<CachedGuildUser> Members => _members.ToReadOnlyCollection();
 
         public CachedGuild(DiscordSocketClient discord, ExtendedModel model, DataStore dataStore) : base(discord, model)

src/Discord.Net/Extensions/CollectionExtensions.cs

@@ -11,12 +11,13 @@ namespace Discord.Extensions
         public static IReadOnlyCollection<TValue> ToReadOnlyCollection<TValue, TSource>(this IEnumerable<TValue> query, IReadOnlyCollection<TSource> source)
             => new ConcurrentDictionaryWrapper<TValue, TSource>(source, query);
     }
-
+    
     internal struct ConcurrentDictionaryWrapper<TValue, TSource> : IReadOnlyCollection<TValue>
     {
         private readonly IReadOnlyCollection<TSource> _source;
         private readonly IEnumerable<TValue> _query;
 
+        //It's okay that this count is affected by race conditions - we're wrapping a concurrent collection and that's to be expected
         public int Count => _source.Count;
         
         public ConcurrentDictionaryWrapper(IReadOnlyCollection<TSource> source, IEnumerable<TValue> query)

src/Discord.Net/Utilities/DateTimeUtils.cs

@@ -4,15 +4,12 @@ namespace Discord
 {
     internal static class DateTimeUtils
     {
-        private const ulong EpochTicks = 621355968000000000UL;
-        private const ulong DiscordEpochMillis = 1420070400000UL;
+        public static DateTimeOffset FromSnowflake(ulong value)
+            => DateTimeOffset.FromUnixTimeMilliseconds((long)((value >> 22) + 1420070400000UL));
 
-        public static DateTime FromEpochMilliseconds(ulong value)
-            => new DateTime((long)(value * TimeSpan.TicksPerMillisecond + EpochTicks), DateTimeKind.Utc);
-        public static DateTime FromEpochSeconds(ulong value)
-            => new DateTime((long)(value * TimeSpan.TicksPerSecond + EpochTicks), DateTimeKind.Utc);
-
-        public static DateTime FromSnowflake(ulong value)
-            => FromEpochMilliseconds((value >> 22) + DiscordEpochMillis);
+        public static DateTimeOffset FromTicks(long ticks)
+            => new DateTimeOffset(ticks, TimeSpan.Zero);
+        public static DateTimeOffset? FromTicks(long? ticks)
+            => ticks != null ? new DateTimeOffset(ticks.Value, TimeSpan.Zero) : (DateTimeOffset?)null;
     }
 }