Implemented new CommandMap

src/Discord.Net.Commands/CommandService.cs

@@ -14,8 +14,8 @@ namespace Discord.Commands
     {
         private readonly SemaphoreSlim _moduleLock;
         private readonly ConcurrentDictionary<object, Module> _modules;
-        private readonly ConcurrentDictionary<string, List<Command>> _map;
         private readonly ConcurrentDictionary<Type, TypeReader> _typeReaders;
+        private readonly CommandMap _map;
 
         public IEnumerable<Module> Modules => _modules.Select(x => x.Value);
         public IEnumerable<Command> Commands => _modules.SelectMany(x => x.Value.Commands);
@@ -24,7 +24,7 @@ namespace Discord.Commands
         {
             _moduleLock = new SemaphoreSlim(1, 1);
             _modules = new ConcurrentDictionary<object, Module>();
-            _map = new ConcurrentDictionary<string, List<Command>>();
+            _map = new CommandMap();
             _typeReaders = new ConcurrentDictionary<Type, TypeReader>
             {
                 [typeof(string)] = new GenericTypeReader((m, s) => Task.FromResult(TypeReaderResult.FromSuccess(s))),
@@ -160,11 +160,7 @@ namespace Discord.Commands
             _modules[moduleInstance] = loadedModule;
 
             foreach (var cmd in loadedModule.Commands)
-            {
-                var list = _map.GetOrAdd(cmd.Text, _ => new List<Command>());
-                lock (list)
-                    list.Add(cmd);
-            }
+                _map.AddCommand(cmd);
 
             return loadedModule;
         }
@@ -222,14 +218,7 @@ namespace Discord.Commands
             if (_modules.TryRemove(module, out unloadedModule))
             {
                 foreach (var cmd in unloadedModule.Commands)
-                {
-                    List<Command> list;
-                    if (_map.TryGetValue(cmd.Text, out list))
-                    {
-                        lock (list)
-                            list.Remove(cmd);
-                    }
-                }
+                    _map.RemoveCommand(cmd);
                 return true;
             }
             else
@@ -240,35 +229,10 @@ namespace Discord.Commands
         public SearchResult Search(IMessage message, string input)
         {
             string lowerInput = input.ToLowerInvariant();
-
-            ImmutableArray<Command>.Builder matches = null;
-            List<Command> group;
-            int pos = -1;
-
-            while (true)
-            {
-                pos = input.IndexOf(' ', pos + 1);
-                string cmdText = pos == -1 ? input : input.Substring(0, pos);
-                if (!_map.TryGetValue(cmdText, out group))
-                    break;
-
-                lock (group)
-                {
-                    if (matches == null)
-                        matches = ImmutableArray.CreateBuilder<Command>(group.Count);
-                    for (int i = 0; i < group.Count; i++)
-                        matches.Add(group[i]);
-                }
-
-                if (pos == -1)
-                {
-                    pos = input.Length;
-                    break;
-                }
-            }
+            var matches = _map.GetCommands(input).ToImmutableArray();
             
-            if (matches != null)
-                return SearchResult.FromSuccess(input, matches.ToImmutable());
+            if (matches.Length > 0)
+                return SearchResult.FromSuccess(input, matches);
             else
                 return SearchResult.FromError(CommandError.UnknownCommand, "Unknown command.");
         }

src/Discord.Net.Commands/Map/CommandMap.cs

@@ -0,0 +1,76 @@
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+
+namespace Discord.Commands
+{
+    internal class CommandMap
+    {
+        private readonly ConcurrentDictionary<string, CommandMapNode> _nodes;
+
+        public CommandMap()
+        {
+            _nodes = new ConcurrentDictionary<string, CommandMapNode>();
+        }
+
+        public void AddCommand(Command command)
+        {
+            string text = command.Text;
+            int nextSpace = text.IndexOf(' ');
+            string name;
+
+            lock (this)
+            {
+                if (nextSpace == -1)
+                    name = command.Text;
+                else
+                    name = command.Text.Substring(0, nextSpace);
+                var nextNode = _nodes.GetOrAdd(name, x => new CommandMapNode(x));
+                nextNode.AddCommand(nextSpace == -1 ? "" : text, nextSpace + 1, command);
+            }
+        }
+        public void RemoveCommand(Command command)
+        {
+            string text = command.Text;
+            int nextSpace = text.IndexOf(' ');
+            string name;
+
+            lock (this)
+            {
+                if (nextSpace == -1)
+                    name = command.Text;
+                else
+                    name = command.Text.Substring(0, nextSpace);
+
+                CommandMapNode nextNode;
+                if (_nodes.TryGetValue(name, out nextNode))
+                {
+                    nextNode.AddCommand(nextSpace == -1 ? "" : text, nextSpace + 1, command);
+                    if (nextNode.IsEmpty)
+                        _nodes.TryRemove(name, out nextNode);
+                }
+            }
+        }
+
+        public IEnumerable<Command> GetCommands(string text)
+        {
+            int nextSpace = text.IndexOf(' ');
+            string name;
+
+            lock (this)
+            {
+                if (nextSpace == -1)
+                    name = text;
+                else
+                    name = text.Substring(0, nextSpace);
+
+                CommandMapNode nextNode;
+                if (_nodes.TryGetValue(name, out nextNode))
+                    return nextNode.GetCommands(text, nextSpace + 1);
+                else
+                    return Enumerable.Empty<Command>();
+            }
+        }
+    }
+}

src/Discord.Net.Commands/Map/CommandMapNode.cs

@@ -0,0 +1,95 @@
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace Discord.Commands
+{
+    internal class CommandMapNode
+    {
+        private readonly ConcurrentDictionary<string, CommandMapNode> _nodes;
+        private readonly string _name;
+        private ImmutableArray<Command> _commands;
+
+        public bool IsEmpty => _commands.Length == 0 && _nodes.Count == 0;
+
+        public CommandMapNode(string name)
+        {
+            _name = name;
+            _nodes = new ConcurrentDictionary<string, CommandMapNode>();
+            _commands = ImmutableArray.Create<Command>();
+        }
+
+        public void AddCommand(string text, int index, Command command)
+        {
+            int nextSpace = text.IndexOf(' ', index);
+            string name;
+
+            lock (this)
+            {
+                if (text == "")
+                    _commands = _commands.Add(command);
+                else
+                {
+                    if (nextSpace == -1)
+                        name = text.Substring(index);
+                    else
+                        name = text.Substring(index, nextSpace - index);
+
+                    var nextNode = _nodes.GetOrAdd(name, x => new CommandMapNode(x));
+                    nextNode.AddCommand(nextSpace == -1 ? "" : text, nextSpace + 1, command);
+                }
+            }
+        }
+        public void RemoveCommand(string text, int index, Command command)
+        {
+            int nextSpace = text.IndexOf(' ', index);
+            string name;
+
+            lock (this)
+            {
+                if (text == "")
+                    _commands = _commands.Remove(command);
+                else
+                {
+                    if (nextSpace == -1)
+                        name = text.Substring(index);
+                    else
+                        name = text.Substring(index, nextSpace - index);
+
+                    CommandMapNode nextNode;
+                    if (_nodes.TryGetValue(name, out nextNode))
+                    {
+                        nextNode.RemoveCommand(nextSpace == -1 ? "" : text, nextSpace + 1, command);
+                        if (nextNode.IsEmpty)
+                            _nodes.TryRemove(name, out nextNode);
+                    }
+                }
+            }
+        }
+
+        public IEnumerable<Command> GetCommands(string text, int index)
+        {
+            int nextSpace = text.IndexOf(' ', index);
+            string name;
+
+            var commands = _commands;
+            for (int i = 0; i < commands.Length; i++)
+                yield return _commands[i];
+
+            if (text != "")
+            {
+                if (nextSpace == -1)
+                    name = text.Substring(index);
+                else
+                    name = text.Substring(index, nextSpace - index);
+
+                CommandMapNode nextNode;
+                if (_nodes.TryGetValue(name, out nextNode))
+                {
+                    foreach (var cmd in nextNode.GetCommands(nextSpace == -1 ? "" : text, nextSpace + 1))
+                        yield return cmd;
+                }
+            }
+        }
+    }
+}