finish implementing path parameters

SimpleHttpServer/Types/EndpointInvocationInfo.cs

@@ -2,23 +2,46 @@
 using System.Reflection;
 
 namespace SimpleHttpServer.Types;
-internal readonly struct EndpointInvocationInfo {
-    internal record struct QueryParameterInfo(string Name, Type Type, bool IsOptional);
+internal record EndpointInvocationInfo {
+    //internal record struct QueryParameterInfo(string Name, Type Type, bool isPathParam, bool Path_isCatchAll, bool Query_IsOptional) {
+    //    public static QueryParameterInfo CreatePathParam(string name, Type type) => new(name, type, false, name == "$*", false);
+    //    public static QueryParameterInfo CreateQueryParam(string name, Type type, bool isOptional) => new(name, type, false, false, isOptional);
+    //}
+    internal record struct PathParameterInfo(string Name, Type Type, int ArgPos, int SegmentStartPos, bool IsCatchAll) {
+        public PathParameterInfo(string name, Type type, int argPos) : this(name, type, argPos, -1, name == "$*") { }
+    }
+
+    internal record struct QueryParameterInfo(string Name, Type Type, int ArgPos, bool IsOptional);
 
     internal readonly MethodInfo methodInfo;
     internal readonly List<QueryParameterInfo> queryParameters;
+    internal readonly List<PathParameterInfo> pathParameters;
     internal readonly InternalEndpointCheckAttribute[] requiredChecks;
     /// <summary>
     /// a reference to the object in which this method is defined (or null if the class is static)
     /// </summary>
     internal readonly object? typeInstanceReference;
 
-    public EndpointInvocationInfo(MethodInfo methodInfo, List<QueryParameterInfo> queryParameters, InternalEndpointCheckAttribute[] requiredChecks, object? typeInstanceReference) {
+    public EndpointInvocationInfo(MethodInfo methodInfo, List<PathParameterInfo> pathParameters, List<QueryParameterInfo> queryParameters, InternalEndpointCheckAttribute[] requiredChecks, 
+        object? typeInstanceReference) {
+
         this.methodInfo = methodInfo ?? throw new ArgumentNullException(nameof(methodInfo));
         this.queryParameters = queryParameters ?? throw new ArgumentNullException(nameof(queryParameters));
+        this.pathParameters = pathParameters ?? throw new ArgumentNullException(nameof(pathParameters));
         this.requiredChecks = requiredChecks;
         this.typeInstanceReference = typeInstanceReference;
+
+        if (pathParameters.Any()) {
+            Assert(pathParameters.Count(x => x.IsCatchAll) <= 1); // at most one catchall parameter
+            var argPoses = pathParameters.Select(x => x.ArgPos).Concat(queryParameters.Select(x => x.ArgPos)).ToArray();
+            var argCnt = pathParameters.Count + queryParameters.Count;
+            Assert(argPoses.Distinct().Count() == argCnt); // ArgPoses must be unique
+            Assert(argPoses.Min() == HttpServer.expectedEndpointParameterPrefixCount); // ArgPoses must start from just after the prefix
+            Assert(argPoses.Max() == HttpServer.expectedEndpointParameterPrefixCount + argCnt - 1); // ArgPoses must be contiguous
+
+            Assert(pathParameters.All(x => x.SegmentStartPos != -1));
+        }
     }
 
-    public readonly bool CheckAll(HttpListenerRequest req) => requiredChecks.All(x => x.Check(req));
+    public bool CheckAll(HttpListenerRequest req) => requiredChecks.All(x => x.Check(req));
 }

SimpleHttpServer/Types/MultiKeyDictionary.cs

@@ -0,0 +1,22 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace SimpleHttpServer.Types;
+internal class MultiKeyDictionary<K1, K2, V> where K1 : notnull where K2 : notnull {
+    internal readonly Dictionary<K1, Dictionary<K2, V>> backingDict = new();
+    public MultiKeyDictionary() { }
+
+    public void Add(K1 k1, K2 k2, V value) {
+        if (!backingDict.TryGetValue(k1, out var d2))
+            d2 = new();
+        d2.Add(k2, value);
+        backingDict[k1] = d2;
+    }
+
+    public bool TryGetValue(K1 k1, K2 k2, [MaybeNullWhen(false)] out V value) {
+        if (backingDict.TryGetValue(k1, out var d2) && d2.TryGetValue(k2, out value))
+            return true;
+
+        value = default;
+        return false;
+    }
+}

SimpleHttpServer/Types/PathParameterAttribute.cs

@@ -19,6 +19,10 @@ public sealed class PathParameterAttribute : Attribute {
             throw new ArgumentException($"'{nameof(name)}' must not contain spaces.", nameof(name));
         }
 
+        if (!uint.TryParse(name[1..], out _) && name != "$*") {
+            throw new ArgumentException($"'{nameof(name)}' must only consist of spaces or be exactly '$*'.", nameof(name));
+        }
+
         Name = name;
     }
 }

SimpleHttpServer/Types/PathTree.cs

@@ -0,0 +1,107 @@
+using System.Data;
+using System.Diagnostics.CodeAnalysis;
+
+namespace SimpleHttpServer.Types;
+
+internal class PathTree<T> where T : class {
+    private readonly Node? rootNode = null;
+
+    public PathTree() : this(new()) { }
+    public PathTree(Dictionary<string, T> dict) {
+        if (dict == null || dict.Count == 0)
+            return;
+
+        rootNode = new();
+        var currNode = rootNode;
+        var unpackedPaths = dict.Keys.Select(p => p.Split('/').ToArray()).ToArray();
+        var unpackedLeafData = dict.Values.ToArray();
+        for (int i = 0; i < unpackedPaths.Length; i++) {
+            var path = unpackedPaths[i];
+            var catchallidx = Array.IndexOf(path, "$*");
+            if (catchallidx != -1 && catchallidx != path.Length - 1) {
+                throw new Exception($"Found illegal catchall-wildcard in path: '{string.Join('/', path)}'");
+            }
+
+            var leafdata = unpackedLeafData[i];
+            rootNode.AddSuccessor(path, leafdata);
+        }
+    }
+
+    internal bool TryGetPath(string reqPath, [MaybeNullWhen(false)] out T? endpoint) {
+        if (rootNode == null) {
+            endpoint = null;
+            return false;
+        }
+
+        // try to find path-match
+        Node currNode = rootNode;
+        Assert(reqPath[0] == '/');
+        var splittedPath = reqPath[1..].Split("/");
+        Node? lastCatchallNode = null;
+        for (int i = 0; i < splittedPath.Length; i++) {
+
+            // keep track of the current best catchallNode
+            if (currNode.catchAllNext != null) {
+                lastCatchallNode = currNode.catchAllNext;
+            }
+
+            var seg = splittedPath[i];
+            if (currNode.next?.TryGetValue(seg, out var next) == true) { // look for an explicit path to follow greedily
+                currNode = next;
+            } else if (currNode.pathWildcardNext != null) { // otherwise look for a single-wildcard to follow
+                currNode = currNode.pathWildcardNext;
+            } else { // otherwise we are done, there is no valid path --> fall back to the most specific catchall
+                endpoint = lastCatchallNode?.leafData;
+                return lastCatchallNode != null;
+            }
+        }
+
+        // return found path
+        endpoint = currNode.leafData;
+        return true;
+    }
+
+    private class Node {
+        public T? leafData = null;
+        public Dictionary<string, Node>? next = null;
+        public Node? pathWildcardNext = null; // path wildcard
+        public Node? catchAllNext = null; // trailing-catchall wildcard
+
+        public void AddSuccessor(string[] segments, T? newLeafData) {
+            if (segments.Length == 0) { // actually add the data to this node
+                Assert(leafData == null);
+                leafData = newLeafData;
+                return;
+            }
+
+            var seg = segments[0];
+            bool newIsWildcard = seg.Length > 1 && seg[0] == '$';
+            if (newIsWildcard) {
+                bool newIsCatchallWildcard = newIsWildcard && seg.Length == 2 && seg[1] == '*';
+                if (newIsCatchallWildcard) { // this is a catchall wildcard
+                    Assert(catchAllNext == null);
+                    catchAllNext = new();
+                    catchAllNext.AddSuccessor(segments[1..], newLeafData);
+                    return;
+                } else { // must be single wildcard otherwise
+                    Assert(pathWildcardNext == null);
+                    pathWildcardNext = new();
+                    pathWildcardNext.AddSuccessor(segments[1..], newLeafData);
+                    return;
+                }
+            }
+
+            // otherwise we want to add a new constant path successor
+            if (next == null) {
+                next = new();
+            }
+
+            if (next.TryGetValue(seg, out var existingNode)) {
+                existingNode.AddSuccessor(segments[1..], newLeafData);
+            } else {
+                var newNode = next[seg] = new();
+                newNode.AddSuccessor(segments[1..], newLeafData);
+            }
+        }
+    }
+}