Port TemplateBinder to dispatcher

benchmarks/Microsoft.AspNetCore.Dispatcher.Performance/DispatcherBenchmark.cs

@@ -31,8 +31,8 @@ namespace Microsoft.AspNetCore.Dispatcher.Performance
             var treeBuilder = new TreeRouteBuilder(
                 NullLoggerFactory.Instance,
                 UrlEncoder.Default,
-                new DefaultObjectPool<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy(UrlEncoder.Default)),
+                new DefaultObjectPool<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy()),
-                new DefaultInlineConstraintResolver(new OptionsManager<RouteOptions>(new OptionsFactory<RouteOptions>(Enumerable.Empty<IConfigureOptions<RouteOptions>>(), Enumerable.Empty<IPostConfigureOptions<RouteOptions>>()))));
+                new DefaultInlineConstraintResolver(Options.Create(new RouteOptions())));
 
             treeBuilder.MapInbound(handler, Routing.Template.TemplateParser.Parse("api/Widgets"), "default", 0);
             treeBuilder.MapInbound(handler, Routing.Template.TemplateParser.Parse("api/Widgets/{id}"), "default", 0);

benchmarks/Microsoft.AspNetCore.Routing.Performance/RoutingBenchmark.cs

@@ -6,8 +6,8 @@ using System.Linq;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
 using BenchmarkDotNet.Attributes;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.AspNetCore.Routing.Template;
 using Microsoft.AspNetCore.Routing.Tree;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -31,8 +31,8 @@ namespace Microsoft.AspNetCore.Routing.Performance
             var treeBuilder = new TreeRouteBuilder(
                 NullLoggerFactory.Instance,
                 UrlEncoder.Default,
-                new DefaultObjectPool<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy(UrlEncoder.Default)),
+                new DefaultObjectPool<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy()),
-                new DefaultInlineConstraintResolver(new OptionsManager<RouteOptions>(new OptionsFactory<RouteOptions>(Enumerable.Empty<IConfigureOptions<RouteOptions>>(), Enumerable.Empty<IPostConfigureOptions<RouteOptions>>()))));
+                new DefaultInlineConstraintResolver(Options.Create(new RouteOptions())));
 
             treeBuilder.MapInbound(handler, TemplateParser.Parse("api/Widgets"), "default", 0);
             treeBuilder.MapInbound(handler, TemplateParser.Parse("api/Widgets/{id}"), "default", 0);

src/Microsoft.AspNetCore.Dispatcher/BufferValue.cs

@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-namespace Microsoft.AspNetCore.Routing.Internal
+namespace Microsoft.AspNetCore.Dispatcher
 {
     public struct BufferValue
     {

src/Microsoft.AspNetCore.Dispatcher/DispatcherServiceCollectionExtensions.cs

@@ -5,6 +5,7 @@ using System;
 using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.ObjectPool;
 using Microsoft.Extensions.Options;
 
 namespace Microsoft.Extensions.DependencyInjection
@@ -18,7 +19,7 @@ namespace Microsoft.Extensions.DependencyInjection
                 throw new ArgumentNullException(nameof(services));
             }
 
-            // Adds the EndpointMiddleare at the end of the pipeline if the DispatcherMiddleware is in use.
+            // Adds the EndpointMiddleware at the end of the pipeline if the DispatcherMiddleware is in use.
             services.TryAddEnumerable(ServiceDescriptor.Singleton<IStartupFilter, DispatcherEndpointStartupFilter>());
 
             // Adds a default dispatcher which will collect all data sources and endpoint selectors from DI.
@@ -27,6 +28,15 @@ namespace Microsoft.Extensions.DependencyInjection
             services.AddSingleton<AddressTable, DefaultAddressTable>();
             services.AddSingleton<TemplateAddressSelector>();
 
+            //
+            // Infrastructure
+            //
+            services.AddSingleton<ObjectPool<UriBuildingContext>>(s =>
+            {
+                var provider = s.GetRequiredService<ObjectPoolProvider>();
+                return provider.Create<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy());
+            });
+
             services.TryAddEnumerable(ServiceDescriptor.Singleton<IHandlerFactory, TemplateEndpointHandlerFactory>());
 
             return services;

src/Microsoft.AspNetCore.Dispatcher/Microsoft.AspNetCore.Dispatcher.csproj

@@ -16,6 +16,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Http.Extensions" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" />
     <PackageReference Include="Microsoft.Extensions.HashCodeCombiner.Sources" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.Extensions.ObjectPool" />
     <PackageReference Include="Microsoft.Extensions.Options" />
   </ItemGroup>
 

src/Microsoft.AspNetCore.Dispatcher/RoutePatternBinder.cs

@@ -0,0 +1,441 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections;
+using System.Diagnostics;
+using System.Globalization;
+using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Dispatcher.Patterns;
+using Microsoft.Extensions.ObjectPool;
+
+namespace Microsoft.AspNetCore.Dispatcher
+{
+    public class RoutePatternBinder
+    {
+        private readonly UrlEncoder _urlEncoder;
+        private readonly ObjectPool<UriBuildingContext> _pool;
+
+        private readonly DispatcherValueCollection _defaults;
+        private readonly DispatcherValueCollection _filters;
+        private readonly RoutePattern _pattern;
+
+        public RoutePatternBinder(
+            UrlEncoder urlEncoder,
+            ObjectPool<UriBuildingContext> pool,
+            RoutePattern template,
+            DispatcherValueCollection defaults)
+        {
+            if (urlEncoder == null)
+            {
+                throw new ArgumentNullException(nameof(urlEncoder));
+            }
+
+            if (pool == null)
+            {
+                throw new ArgumentNullException(nameof(pool));
+            }
+
+            if (template == null)
+            {
+                throw new ArgumentNullException(nameof(template));
+            }
+
+            _urlEncoder = urlEncoder;
+            _pool = pool;
+            _pattern = template;
+            _defaults = defaults;
+
+            // Any default that doesn't have a corresponding parameter is a 'filter' and if a value
+            // is provided for that 'filter' it must match the value in defaults.
+            _filters = new DispatcherValueCollection(_defaults);
+            foreach (var parameter in _pattern.Parameters)
+            {
+                _filters.Remove(parameter.Name);
+            }
+        }
+
+        // Step 1: Get the list of values we're going to try to use to match and generate this URI
+        public (DispatcherValueCollection acceptedValues, DispatcherValueCollection combinedValues) GetValues(DispatcherValueCollection ambientValues, DispatcherValueCollection values)
+        {
+            var context = new TemplateBindingContext(_defaults);
+
+            // Find out which entries in the URI are valid for the URI we want to generate.
+            // If the URI had ordered parameters a="1", b="2", c="3" and the new values
+            // specified that b="9", then we need to invalidate everything after it. The new
+            // values should then be a="1", b="9", c=<no value>.
+            //
+            // We also handle the case where a parameter is optional but has no value - we shouldn't
+            // accept additional parameters that appear *after* that parameter.
+            for (var i = 0; i < _pattern.Parameters.Count; i++)
+            {
+                var parameter = _pattern.Parameters[i];
+
+                // If it's a parameter subsegment, examine the current value to see if it matches the new value
+                var parameterName = parameter.Name;
+
+                object newParameterValue;
+                var hasNewParameterValue = values.TryGetValue(parameterName, out newParameterValue);
+
+                object currentParameterValue = null;
+                var hasCurrentParameterValue = ambientValues != null &&
+                                               ambientValues.TryGetValue(parameterName, out currentParameterValue);
+
+                if (hasNewParameterValue && hasCurrentParameterValue)
+                {
+                    if (!RoutePartsEqual(currentParameterValue, newParameterValue))
+                    {
+                        // Stop copying current values when we find one that doesn't match
+                        break;
+                    }
+                }
+
+                if (!hasNewParameterValue && 
+                    !hasCurrentParameterValue && 
+                    _defaults?.ContainsKey(parameter.Name) != true)
+                {
+                    // This is an unsatisfied parameter value and there are no defaults. We might still
+                    // be able to generate a URL but we should stop 'accepting' ambient values.
+                    //
+                    // This might be a case like:
+                    //  template: a/{b?}/{c?}
+                    //  ambient: { c = 17 }
+                    //  values: { }
+                    //
+                    // We can still generate a URL from this ("/a") but we shouldn't accept 'c' because
+                    // we can't use it.
+                    // 
+                    // In the example above we should fall into this block for 'b'.
+                    break;
+                }
+
+                // If the parameter is a match, add it to the list of values we will use for URI generation
+                if (hasNewParameterValue)
+                {
+                    if (IsRoutePartNonEmpty(newParameterValue))
+                    {
+                        context.Accept(parameterName, newParameterValue);
+                    }
+                }
+                else
+                {
+                    if (hasCurrentParameterValue)
+                    {
+                        context.Accept(parameterName, currentParameterValue);
+                    }
+                }
+            }
+
+            // Add all remaining new values to the list of values we will use for URI generation
+            foreach (var kvp in values)
+            {
+                if (IsRoutePartNonEmpty(kvp.Value))
+                {
+                    context.Accept(kvp.Key, kvp.Value);
+                }
+            }
+
+            // Accept all remaining default values if they match a required parameter
+            for (var i = 0; i < _pattern.Parameters.Count; i++)
+            {
+                var parameter = _pattern.Parameters[i];
+                if (parameter.IsOptional || parameter.IsCatchAll)
+                {
+                    continue;
+                }
+
+                if (context.NeedsValue(parameter.Name))
+                {
+                    // Add the default value only if there isn't already a new value for it and
+                    // only if it actually has a default value, which we determine based on whether
+                    // the parameter value is required.
+                    context.AcceptDefault(parameter.Name);
+                }
+            }
+
+            // Validate that all required parameters have a value.
+            for (var i = 0; i < _pattern.Parameters.Count; i++)
+            {
+                var parameter = _pattern.Parameters[i];
+                if (parameter.IsOptional || parameter.IsCatchAll)
+                {
+                    continue;
+                }
+
+                if (!context.AcceptedValues.ContainsKey(parameter.Name))
+                {
+                    // We don't have a value for this parameter, so we can't generate a url.
+                    return (null, null);
+                }
+            }
+
+            // Any default values that don't appear as parameters are treated like filters. Any new values
+            // provided must match these defaults.
+            foreach (var filter in _filters)
+            {
+                var parameter = _pattern.GetParameter(filter.Key);
+                if (parameter != null)
+                {
+                    continue;
+                }
+
+                object value;
+                if (values.TryGetValue(filter.Key, out value))
+                {
+                    if (!RoutePartsEqual(value, filter.Value))
+                    {
+                        // If there is a non-parameterized value in the route and there is a
+                        // new value for it and it doesn't match, this route won't match.
+                        return (null, null);
+                    }
+                }
+            }
+
+            // Add any ambient values that don't match parameters - they need to be visible to constraints
+            // but they will ignored by link generation.
+            var combinedValues = new DispatcherValueCollection(context.AcceptedValues);
+            if (ambientValues != null)
+            {
+                foreach (var kvp in ambientValues)
+                {
+                    if (IsRoutePartNonEmpty(kvp.Value))
+                    {
+                        var parameter = _pattern.GetParameter(kvp.Key);
+                        if (parameter == null && !context.AcceptedValues.ContainsKey(kvp.Key))
+                        {
+                            combinedValues.Add(kvp.Key, kvp.Value);
+                        }
+                    }
+                }
+            }
+
+            return (context.AcceptedValues, combinedValues);
+        }
+
+        // Step 2: If the route is a match generate the appropriate URI
+        public string BindValues(DispatcherValueCollection acceptedValues)
+        {
+            var context = _pool.Get();
+            var result = BindValues(context, acceptedValues);
+            _pool.Return(context);
+            return result;
+        }
+
+        private string BindValues(UriBuildingContext context, DispatcherValueCollection acceptedValues)
+        {
+            for (var i = 0; i < _pattern.PathSegments.Count; i++)
+            {
+                Debug.Assert(context.BufferState == SegmentState.Beginning);
+                Debug.Assert(context.UriState == SegmentState.Beginning);
+
+                var segment = _pattern.PathSegments[i];
+
+                for (var j = 0; j < segment.Parts.Count; j++)
+                {
+                    var part = segment.Parts[j];
+
+                    if (part.IsLiteral)
+                    {
+                        if (!context.Accept(_urlEncoder, ((RoutePatternLiteral)part).Content))
+                        {
+                            return null;
+                        }
+                    }
+                    else if (part.IsSeparator)
+                    {
+                        if (!context.Accept(_urlEncoder, ((RoutePatternSeparator)part).Content))
+                        {
+                            return null;
+                        }
+                    }
+                    else if (part.IsParameter && part is RoutePatternParameter parameter)
+                    {
+                        // If it's a parameter, get its value
+                        object value;
+                        var hasValue = acceptedValues.TryGetValue(parameter.Name, out value);
+                        if (hasValue)
+                        {
+                            acceptedValues.Remove(parameter.Name);
+                        }
+
+                        var isSameAsDefault = false;
+                        object defaultValue;
+                        if (_defaults != null && _defaults.TryGetValue(parameter.Name, out defaultValue))
+                        {
+                            if (RoutePartsEqual(value, defaultValue))
+                            {
+                                isSameAsDefault = true;
+                            }
+                        }
+
+                        var converted = Convert.ToString(value, CultureInfo.InvariantCulture);
+                        if (isSameAsDefault)
+                        {
+                            // If the accepted value is the same as the default value buffer it since
+                            // we won't necessarily add it to the URI we generate.
+                            if (!context.Buffer(_urlEncoder, converted))
+                            {
+                                return null;
+                            }
+                        }
+                        else
+                        {
+                            // If the value is not accepted, it is null or empty value in the 
+                            // middle of the segment. We accept this if the parameter is an
+                            // optional parameter and it is preceded by an optional seperator.
+                            // I this case, we need to remove the optional seperator that we
+                            // have added to the URI
+                            // Example: template = {id}.{format?}. parameters: id=5
+                            // In this case after we have generated "5.", we wont find any value 
+                            // for format, so we remove '.' and generate 5.
+                            if (!context.Accept(_urlEncoder, converted))
+                            {
+                                if (j != 0 && parameter.IsOptional && segment.Parts[j - 1].IsSeparator)
+                                {
+                                    context.Remove(((RoutePatternSeparator)segment.Parts[j - 1]).Content);
+                                }
+                                else
+                                {
+                                    return null;
+                                }
+                            }
+                        }
+                    }
+                }
+
+                context.EndSegment();
+            }
+
+            // Generate the query string from the remaining values
+            var wroteFirst = false;
+            foreach (var kvp in acceptedValues)
+            {
+                if (_defaults != null && _defaults.ContainsKey(kvp.Key))
+                {
+                    // This value is a 'filter' we don't need to put it in the query string.
+                    continue;
+                }
+
+                var values = kvp.Value as IEnumerable;
+                if (values != null && !(values is string))
+                {
+                    foreach (var value in values)
+                    {
+                        wroteFirst |= AddParameterToContext(context, kvp.Key, value, wroteFirst);
+                    }
+                }
+                else
+                {
+                    wroteFirst |= AddParameterToContext(context, kvp.Key, kvp.Value, wroteFirst);
+                }
+            }
+            return context.ToString();
+        }
+
+        private bool AddParameterToContext(UriBuildingContext context, string key, object value, bool wroteFirst)
+        {
+            var converted = Convert.ToString(value, CultureInfo.InvariantCulture);
+            if (!string.IsNullOrEmpty(converted))
+            {
+                context.Writer.Write(wroteFirst ? '&' : '?');
+                _urlEncoder.Encode(context.Writer, key);
+                context.Writer.Write('=');
+                _urlEncoder.Encode(context.Writer, converted);
+                return true;
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Compares two objects for equality as parts of a case-insensitive path.
+        /// </summary>
+        /// <param name="a">An object to compare.</param>
+        /// <param name="b">An object to compare.</param>
+        /// <returns>True if the object are equal, otherwise false.</returns>
+        public static bool RoutePartsEqual(object a, object b)
+        {
+            var sa = a as string;
+            var sb = b as string;
+
+            if (sa != null && sb != null)
+            {
+                // For strings do a case-insensitive comparison
+                return string.Equals(sa, sb, StringComparison.OrdinalIgnoreCase);
+            }
+            else
+            {
+                if (a != null && b != null)
+                {
+                    // Explicitly call .Equals() in case it is overridden in the type
+                    return a.Equals(b);
+                }
+                else
+                {
+                    // At least one of them is null. Return true if they both are
+                    return a == b;
+                }
+            }
+        }
+
+        private static bool IsRoutePartNonEmpty(object routePart)
+        {
+            var routePartString = routePart as string;
+            if (routePartString == null)
+            {
+                return routePart != null;
+            }
+            else
+            {
+                return routePartString.Length > 0;
+            }
+        }
+
+        [DebuggerDisplay("{DebuggerToString(),nq}")]
+        private struct TemplateBindingContext
+        {
+            private readonly DispatcherValueCollection _defaults;
+            private readonly DispatcherValueCollection _acceptedValues;
+
+            public TemplateBindingContext(DispatcherValueCollection defaults)
+            {
+                _defaults = defaults;
+
+                _acceptedValues = new DispatcherValueCollection();
+            }
+
+            public DispatcherValueCollection AcceptedValues
+            {
+                get { return _acceptedValues; }
+            }
+
+            public void Accept(string key, object value)
+            {
+                if (!_acceptedValues.ContainsKey(key))
+                {
+                    _acceptedValues.Add(key, value);
+                }
+            }
+
+            public void AcceptDefault(string key)
+            {
+                Debug.Assert(!_acceptedValues.ContainsKey(key));
+
+                object value;
+                if (_defaults != null && _defaults.TryGetValue(key, out value))
+                {
+                    _acceptedValues.Add(key, value);
+                }
+            }
+
+            public bool NeedsValue(string key)
+            {
+                return !_acceptedValues.ContainsKey(key);
+            }
+
+            private string DebuggerToString()
+            {
+                return string.Format("{{Accepted: '{0}'}}", string.Join(", ", _acceptedValues.Keys));
+            }
+        }
+    }
+}

src/Microsoft.AspNetCore.Dispatcher/SegmentState.cs

@@ -1,7 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-namespace Microsoft.AspNetCore.Routing.Internal
+namespace Microsoft.AspNetCore.Dispatcher
 {
     // Segments are treated as all-or-none. We should never output a partial segment.
     // If we add any subsegment of this segment to the generated URI, we have to add

src/Microsoft.AspNetCore.Dispatcher/UriBuilderContextPooledObjectPolicy.cs

@@ -1,29 +1,15 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-using System.Text.Encodings.Web;
 using Microsoft.Extensions.ObjectPool;
 
-namespace Microsoft.AspNetCore.Routing.Internal
+namespace Microsoft.AspNetCore.Dispatcher
 {
     public class UriBuilderContextPooledObjectPolicy : IPooledObjectPolicy<UriBuildingContext>
     {
-        private readonly UrlEncoder _encoder;
-
-        public UriBuilderContextPooledObjectPolicy(UrlEncoder encoder)
-        {
-            if (encoder == null)
-            {
-                throw new ArgumentNullException(nameof(encoder));
-            }
-
-            _encoder = encoder;
-        }
-
         public UriBuildingContext Create()
         {
-            return new UriBuildingContext(_encoder);
+            return new UriBuildingContext();
         }
 
         public bool Return(UriBuildingContext obj)

src/Microsoft.AspNetCore.Dispatcher/UriBuildingContext.cs

@@ -7,7 +7,7 @@ using System.IO;
 using System.Text;
 using System.Text.Encodings.Web;
 
-namespace Microsoft.AspNetCore.Routing.Internal
+namespace Microsoft.AspNetCore.Dispatcher
 {
     [DebuggerDisplay("{DebuggerToString(),nq}")]
     public class UriBuildingContext
@@ -19,14 +19,12 @@ namespace Microsoft.AspNetCore.Routing.Internal
         // segment is in the middle of the uri. We don't know if we need to write it out - if it's
         // followed by other optional segments than we will just throw it away.
         private readonly List<BufferValue> _buffer;
-        private readonly UrlEncoder _urlEncoder;
 
         private bool _hasEmptySegment;
         private int _lastValueOffset;
 
-        public UriBuildingContext(UrlEncoder urlEncoder)
+        public UriBuildingContext()
         {
-            _urlEncoder = urlEncoder;
             _uri = new StringBuilder();
             _buffer = new List<BufferValue>();
             Writer = new StringWriter(_uri);
@@ -42,7 +40,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
 
         public TextWriter Writer { get; }
 
-        public bool Accept(string value)
+        public bool Accept(UrlEncoder encoder, string value)
         {
             if (string.IsNullOrEmpty(value))
             {
@@ -67,7 +65,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
             {
                 if (_buffer[i].RequiresEncoding)
                 {
-                    _urlEncoder.Encode(Writer, _buffer[i].Value);
+                    encoder.Encode(Writer, _buffer[i].Value);
                 }
                 else
                 {
@@ -93,11 +91,11 @@ namespace Microsoft.AspNetCore.Routing.Internal
             if (_uri.Length == 0 && value.Length > 0 && value[0] == '/')
             {
                 _uri.Append("/");
-                _urlEncoder.Encode(Writer, value, 1, value.Length - 1);
+                encoder.Encode(Writer, value, 1, value.Length - 1);
             }
             else
             {
-                _urlEncoder.Encode(Writer, value);
+                encoder.Encode(Writer, value);
             }
 
             return true;
@@ -110,7 +108,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
             _lastValueOffset = -1;
         }
 
-        public bool Buffer(string value)
+        public bool Buffer(UrlEncoder encoder, string value)
         {
             if (string.IsNullOrEmpty(value))
             {
@@ -135,7 +133,7 @@ namespace Microsoft.AspNetCore.Routing.Internal
             {
                 // We've already written part of this segment so there's no point in buffering, we need to
                 // write out the rest or give up.
-                var result = Accept(value);
+                var result = Accept(encoder, value);
 
                 // We've already checked the conditions that could result in a rejected part, so this should
                 // always be true.

src/Microsoft.AspNetCore.Routing/DependencyInjection/RoutingServiceCollectionExtensions.cs

@@ -28,14 +28,11 @@ namespace Microsoft.Extensions.DependencyInjection
                 throw new ArgumentNullException(nameof(services));
             }
 
+            // Routing shares lots of infrastructure with the dispatcher.
+            services.AddDispatcher();
+
             services.TryAddTransient<IInlineConstraintResolver, DefaultInlineConstraintResolver>();
             services.TryAddSingleton(UrlEncoder.Default);
-            services.TryAddSingleton<ObjectPool<UriBuildingContext>>(s =>
-            {
-                var provider = s.GetRequiredService<ObjectPoolProvider>();
-                var encoder = s.GetRequiredService<UrlEncoder>();
-                return provider.Create<UriBuildingContext>(new UriBuilderContextPooledObjectPolicy(encoder));
-            });
 
             // The TreeRouteBuilder is a builder for creating routes, it should stay transient because it's
             // stateful.

src/Microsoft.AspNetCore.Routing/RouteBase.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.AspNetCore.Routing.Logging;

src/Microsoft.AspNetCore.Routing/Template/TemplateBinder.cs

@@ -2,23 +2,15 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections;
-using System.Diagnostics;
-using System.Globalization;
 using System.Text.Encodings.Web;
-using Microsoft.AspNetCore.Routing.Internal;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.Extensions.ObjectPool;
 
 namespace Microsoft.AspNetCore.Routing.Template
 {
     public class TemplateBinder
     {
-        private readonly UrlEncoder _urlEncoder;
+        private readonly RoutePatternBinder _binder;
-        private readonly ObjectPool<UriBuildingContext> _pool;
-
-        private readonly RouteValueDictionary _defaults;
-        private readonly RouteValueDictionary _filters;
-        private readonly RouteTemplate _template;
 
         public TemplateBinder(
             UrlEncoder urlEncoder,
@@ -41,320 +33,29 @@ namespace Microsoft.AspNetCore.Routing.Template
                 throw new ArgumentNullException(nameof(template));
             }
 
-            _urlEncoder = urlEncoder;
+            _binder = new RoutePatternBinder(urlEncoder, pool, template.ToRoutePattern(), defaults);
-            _pool = pool;
-            _template = template;
-            _defaults = defaults;
-
-            // Any default that doesn't have a corresponding parameter is a 'filter' and if a value
-            // is provided for that 'filter' it must match the value in defaults.
-            _filters = new RouteValueDictionary(_defaults);
-            foreach (var parameter in _template.Parameters)
-            {
-                _filters.Remove(parameter.Name);
-            }
         }
 
         // Step 1: Get the list of values we're going to try to use to match and generate this URI
         public TemplateValuesResult GetValues(RouteValueDictionary ambientValues, RouteValueDictionary values)
         {
-            var context = new TemplateBindingContext(_defaults);
+            (var acceptedValues, var combinedValues) = _binder.GetValues(ambientValues, values);
-
+            if (acceptedValues == null || combinedValues == null)
-            // Find out which entries in the URI are valid for the URI we want to generate.
-            // If the URI had ordered parameters a="1", b="2", c="3" and the new values
-            // specified that b="9", then we need to invalidate everything after it. The new
-            // values should then be a="1", b="9", c=<no value>.
-            //
-            // We also handle the case where a parameter is optional but has no value - we shouldn't
-            // accept additional parameters that appear *after* that parameter.
-            for (var i = 0; i < _template.Parameters.Count; i++)
             {
-                var parameter = _template.Parameters[i];
+                return null;
-
-                // If it's a parameter subsegment, examine the current value to see if it matches the new value
-                var parameterName = parameter.Name;
-
-                object newParameterValue;
-                var hasNewParameterValue = values.TryGetValue(parameterName, out newParameterValue);
-
-                object currentParameterValue = null;
-                var hasCurrentParameterValue = ambientValues != null &&
-                                               ambientValues.TryGetValue(parameterName, out currentParameterValue);
-
-                if (hasNewParameterValue && hasCurrentParameterValue)
-                {
-                    if (!RoutePartsEqual(currentParameterValue, newParameterValue))
-                    {
-                        // Stop copying current values when we find one that doesn't match
-                        break;
-                    }
-                }
-
-                if (!hasNewParameterValue && 
-                    !hasCurrentParameterValue && 
-                    _defaults?.ContainsKey(parameter.Name) != true)
-                {
-                    // This is an unsatisfied parameter value and there are no defaults. We might still
-                    // be able to generate a URL but we should stop 'accepting' ambient values.
-                    //
-                    // This might be a case like:
-                    //  template: a/{b?}/{c?}
-                    //  ambient: { c = 17 }
-                    //  values: { }
-                    //
-                    // We can still generate a URL from this ("/a") but we shouldn't accept 'c' because
-                    // we can't use it.
-                    // 
-                    // In the example above we should fall into this block for 'b'.
-                    break;
-                }
-
-                // If the parameter is a match, add it to the list of values we will use for URI generation
-                if (hasNewParameterValue)
-                {
-                    if (IsRoutePartNonEmpty(newParameterValue))
-                    {
-                        context.Accept(parameterName, newParameterValue);
-                    }
-                }
-                else
-                {
-                    if (hasCurrentParameterValue)
-                    {
-                        context.Accept(parameterName, currentParameterValue);
-                    }
-                }
-            }
-
-            // Add all remaining new values to the list of values we will use for URI generation
-            foreach (var kvp in values)
-            {
-                if (IsRoutePartNonEmpty(kvp.Value))
-                {
-                    context.Accept(kvp.Key, kvp.Value);
-                }
-            }
-
-            // Accept all remaining default values if they match a required parameter
-            for (var i = 0; i < _template.Parameters.Count; i++)
-            {
-                var parameter = _template.Parameters[i];
-                if (parameter.IsOptional || parameter.IsCatchAll)
-                {
-                    continue;
-                }
-
-                if (context.NeedsValue(parameter.Name))
-                {
-                    // Add the default value only if there isn't already a new value for it and
-                    // only if it actually has a default value, which we determine based on whether
-                    // the parameter value is required.
-                    context.AcceptDefault(parameter.Name);
-                }
-            }
-
-            // Validate that all required parameters have a value.
-            for (var i = 0; i < _template.Parameters.Count; i++)
-            {
-                var parameter = _template.Parameters[i];
-                if (parameter.IsOptional || parameter.IsCatchAll)
-                {
-                    continue;
-                }
-
-                if (!context.AcceptedValues.ContainsKey(parameter.Name))
-                {
-                    // We don't have a value for this parameter, so we can't generate a url.
-                    return null;
-                }
-            }
-
-            // Any default values that don't appear as parameters are treated like filters. Any new values
-            // provided must match these defaults.
-            foreach (var filter in _filters)
-            {
-                var parameter = GetParameter(filter.Key);
-                if (parameter != null)
-                {
-                    continue;
-                }
-
-                object value;
-                if (values.TryGetValue(filter.Key, out value))
-                {
-                    if (!RoutePartsEqual(value, filter.Value))
-                    {
-                        // If there is a non-parameterized value in the route and there is a
-                        // new value for it and it doesn't match, this route won't match.
-                        return null;
-                    }
-                }
-            }
-
-            // Add any ambient values that don't match parameters - they need to be visible to constraints
-            // but they will ignored by link generation.
-            var combinedValues = new RouteValueDictionary(context.AcceptedValues);
-            if (ambientValues != null)
-            {
-                foreach (var kvp in ambientValues)
-                {
-                    if (IsRoutePartNonEmpty(kvp.Value))
-                    {
-                        var parameter = GetParameter(kvp.Key);
-                        if (parameter == null && !context.AcceptedValues.ContainsKey(kvp.Key))
-                        {
-                            combinedValues.Add(kvp.Key, kvp.Value);
-                        }
-                    }
-                }
             }
 
             return new TemplateValuesResult()
             {
-                AcceptedValues = context.AcceptedValues,
+                AcceptedValues = acceptedValues.AsRouteValueDictionary(),
-                CombinedValues = combinedValues,
+                CombinedValues = combinedValues.AsRouteValueDictionary(),
             };
         }
 
         // Step 2: If the route is a match generate the appropriate URI
         public string BindValues(RouteValueDictionary acceptedValues)
         {
-            var context = _pool.Get();
+            return _binder.BindValues(acceptedValues);
-            var result = BindValues(context, acceptedValues);
-            _pool.Return(context);
-            return result;
-        }
-
-        private string BindValues(UriBuildingContext context, RouteValueDictionary acceptedValues)
-        {
-            for (var i = 0; i < _template.Segments.Count; i++)
-            {
-                Debug.Assert(context.BufferState == SegmentState.Beginning);
-                Debug.Assert(context.UriState == SegmentState.Beginning);
-
-                var segment = _template.Segments[i];
-
-                for (var j = 0; j < segment.Parts.Count; j++)
-                {
-                    var part = segment.Parts[j];
-
-                    if (part.IsLiteral)
-                    {
-                        if (!context.Accept(part.Text))
-                        {
-                            return null;
-                        }
-                    }
-                    else if (part.IsParameter)
-                    {
-                        // If it's a parameter, get its value
-                        object value;
-                        var hasValue = acceptedValues.TryGetValue(part.Name, out value);
-                        if (hasValue)
-                        {
-                            acceptedValues.Remove(part.Name);
-                        }
-
-                        var isSameAsDefault = false;
-                        object defaultValue;
-                        if (_defaults != null && _defaults.TryGetValue(part.Name, out defaultValue))
-                        {
-                            if (RoutePartsEqual(value, defaultValue))
-                            {
-                                isSameAsDefault = true;
-                            }
-                        }
-
-                        var converted = Convert.ToString(value, CultureInfo.InvariantCulture);
-                        if (isSameAsDefault)
-                        {
-                            // If the accepted value is the same as the default value buffer it since
-                            // we won't necessarily add it to the URI we generate.
-                            if (!context.Buffer(converted))
-                            {
-                                return null;
-                            }
-                        }
-                        else
-                        {
-                            // If the value is not accepted, it is null or empty value in the 
-                            // middle of the segment. We accept this if the parameter is an
-                            // optional parameter and it is preceded by an optional seperator.
-                            // I this case, we need to remove the optional seperator that we
-                            // have added to the URI
-                            // Example: template = {id}.{format?}. parameters: id=5
-                            // In this case after we have generated "5.", we wont find any value 
-                            // for format, so we remove '.' and generate 5.
-                            if (!context.Accept(converted))
-                            {
-                                if (j != 0 && part.IsOptional && segment.Parts[j - 1].IsOptionalSeperator)
-                                {
-                                    context.Remove(segment.Parts[j - 1].Text);
-                                }
-                                else
-                                {
-                                    return null;
-                                }
-                            }
-                        }
-                    }
-                }
-
-                context.EndSegment();
-            }
-
-            // Generate the query string from the remaining values
-            var wroteFirst = false;
-            foreach (var kvp in acceptedValues)
-            {
-                if (_defaults != null && _defaults.ContainsKey(kvp.Key))
-                {
-                    // This value is a 'filter' we don't need to put it in the query string.
-                    continue;
-                }
-
-                var values = kvp.Value as IEnumerable;
-                if (values != null && !(values is string))
-                {
-                    foreach (var value in values)
-                    {
-                        wroteFirst |= AddParameterToContext(context, kvp.Key, value, wroteFirst);
-                    }
-                }
-                else
-                {
-                    wroteFirst |= AddParameterToContext(context, kvp.Key, kvp.Value, wroteFirst);
-                }
-            }
-            return context.ToString();
-        }
-
-        private bool AddParameterToContext(UriBuildingContext context, string key, object value, bool wroteFirst)
-        {
-            var converted = Convert.ToString(value, CultureInfo.InvariantCulture);
-            if (!string.IsNullOrEmpty(converted))
-            {
-                context.Writer.Write(wroteFirst ? '&' : '?');
-                _urlEncoder.Encode(context.Writer, key);
-                context.Writer.Write('=');
-                _urlEncoder.Encode(context.Writer, converted);
-                return true;
-            }
-            return false;
-        }
-
-        private TemplatePart GetParameter(string name)
-        {
-            for (var i = 0; i < _template.Parameters.Count; i++)
-            {
-                var parameter = _template.Parameters[i];
-                if (string.Equals(parameter.Name, name, StringComparison.OrdinalIgnoreCase))
-                {
-                    return parameter;
-                }
-            }
-
-            return null;
         }
 
         /// <summary>
@@ -387,66 +88,5 @@ namespace Microsoft.AspNetCore.Routing.Template
                 }
             }
         }
-
-        private static bool IsRoutePartNonEmpty(object routePart)
-        {
-            var routePartString = routePart as string;
-            if (routePartString == null)
-            {
-                return routePart != null;
-            }
-            else
-            {
-                return routePartString.Length > 0;
-            }
-        }
-
-        [DebuggerDisplay("{DebuggerToString(),nq}")]
-        private struct TemplateBindingContext
-        {
-            private readonly RouteValueDictionary _defaults;
-            private readonly RouteValueDictionary _acceptedValues;
-
-            public TemplateBindingContext(RouteValueDictionary defaults)
-            {
-                _defaults = defaults;
-
-                _acceptedValues = new RouteValueDictionary();
-            }
-
-            public RouteValueDictionary AcceptedValues
-            {
-                get { return _acceptedValues; }
-            }
-
-            public void Accept(string key, object value)
-            {
-                if (!_acceptedValues.ContainsKey(key))
-                {
-                    _acceptedValues.Add(key, value);
-                }
-            }
-
-            public void AcceptDefault(string key)
-            {
-                Debug.Assert(!_acceptedValues.ContainsKey(key));
-
-                object value;
-                if (_defaults != null && _defaults.TryGetValue(key, out value))
-                {
-                    _acceptedValues.Add(key, value);
-                }
-            }
-
-            public bool NeedsValue(string key)
-            {
-                return !_acceptedValues.ContainsKey(key);
-            }
-
-            private string DebuggerToString()
-            {
-                return string.Format("{{Accepted: '{0}'}}", string.Join(", ", _acceptedValues.Keys));
-            }
-        }
     }
 }

src/Microsoft.AspNetCore.Routing/Tree/TreeRouteBuilder.cs

@@ -6,7 +6,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Text.Encodings.Web;
-using Microsoft.AspNetCore.Routing.Internal;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Routing.Template;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.ObjectPool;

src/Microsoft.AspNetCore.Routing/Tree/TreeRouter.cs

@@ -7,6 +7,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Dispatcher.Internal;
 using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.AspNetCore.Routing.Logging;

src/Microsoft.AspNetCore.Routing/breakingchanges.netcore.json

@@ -0,0 +1,17 @@
+[
+    {
+      "TypeId": "public class Microsoft.AspNetCore.Routing.Tree.TreeRouter : Microsoft.AspNetCore.Routing.IRouter",
+      "MemberId": "public .ctor(Microsoft.AspNetCore.Routing.Tree.UrlMatchingTree[] trees, System.Collections.Generic.IEnumerable<Microsoft.AspNetCore.Routing.Tree.OutboundRouteEntry> linkGenerationEntries, System.Text.Encodings.Web.UrlEncoder urlEncoder, Microsoft.Extensions.ObjectPool.ObjectPool<Microsoft.AspNetCore.Routing.Internal.UriBuildingContext> objectPool, Microsoft.Extensions.Logging.ILogger routeLogger, Microsoft.Extensions.Logging.ILogger constraintLogger, System.Int32 version)",
+      "Kind": "Removal"
+    },
+    {
+      "TypeId": "public class Microsoft.AspNetCore.Routing.Tree.TreeRouteBuilder",
+      "MemberId": "public .ctor(Microsoft.Extensions.Logging.ILoggerFactory loggerFactory, System.Text.Encodings.Web.UrlEncoder urlEncoder, Microsoft.Extensions.ObjectPool.ObjectPool<Microsoft.AspNetCore.Routing.Internal.UriBuildingContext> objectPool, Microsoft.AspNetCore.Routing.IInlineConstraintResolver constraintResolver)",
+      "Kind": "Removal"
+    },
+    {
+      "TypeId": "public class Microsoft.AspNetCore.Routing.Template.TemplateBinder",
+      "MemberId": "public .ctor(System.Text.Encodings.Web.UrlEncoder urlEncoder, Microsoft.Extensions.ObjectPool.ObjectPool<Microsoft.AspNetCore.Routing.Internal.UriBuildingContext> pool, Microsoft.AspNetCore.Routing.Template.RouteTemplate template, Microsoft.AspNetCore.Routing.RouteValueDictionary defaults)",
+      "Kind": "Removal"
+    }
+]

test/Microsoft.AspNetCore.Dispatcher.Test/Microsoft.AspNetCore.Dispatcher.Test.csproj

@@ -13,6 +13,8 @@
     <PackageReference Include="Microsoft.AspNetCore.Http" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
     <PackageReference Include="Microsoft.Extensions.Logging" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Testing" />
+    <PackageReference Include="Microsoft.Extensions.WebEncoders" />
   </ItemGroup>
   
 </Project>

test/Microsoft.AspNetCore.Routing.Tests/RouteCollectionTest.cs

@@ -591,6 +591,7 @@ namespace Microsoft.AspNetCore.Routing
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
             services.AddOptions();
             services.AddRouting();
+            services.AddDispatcher();
             if (options != null)
             {
                 services.Configure(options);
@@ -613,6 +614,7 @@ namespace Microsoft.AspNetCore.Routing
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
             services.AddOptions();
             services.AddRouting();
+            services.AddDispatcher();
             if (options != null)
             {
                 services.Configure<RouteOptions>(options);

test/Microsoft.AspNetCore.Routing.Tests/RouteTest.cs

@@ -1487,6 +1487,7 @@ namespace Microsoft.AspNetCore.Routing
             services.AddSingleton<ILoggerFactory>(NullLoggerFactory.Instance);
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
             services.AddRouting();
+            services.AddDispatcher();
 
             var context = new DefaultHttpContext
             {

test/Microsoft.AspNetCore.Routing.Tests/Template/TemplateBinderTests.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.ObjectPool;
@@ -119,7 +120,7 @@ namespace Microsoft.AspNetCore.Routing.Template.Tests
             var encoder = new UrlTestEncoder();
             var binder = new TemplateBinder(
                 encoder,
-                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy(encoder)),
+                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy()),
                 TemplateParser.Parse(template),
                 defaults);
 
@@ -269,7 +270,7 @@ namespace Microsoft.AspNetCore.Routing.Template.Tests
             var encoder = new UrlTestEncoder();
             var binder = new TemplateBinder(
                 encoder,
-                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy(encoder)),
+                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy()),
                 TemplateParser.Parse(template),
                 defaults);
 
@@ -699,7 +700,7 @@ namespace Microsoft.AspNetCore.Routing.Template.Tests
             var encoder = new UrlTestEncoder();
             var binder = new TemplateBinder(
                 new UrlTestEncoder(),
-                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy(encoder)),
+                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy()),
                 TemplateParser.Parse(template),
                 defaults: null);
             var ambientValues = new RouteValueDictionary();
@@ -1131,7 +1132,7 @@ namespace Microsoft.AspNetCore.Routing.Template.Tests
 
             var binder = new TemplateBinder(
                 encoder,
-                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy(encoder)),
+                new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy()),
                 TemplateParser.Parse(template),
                 defaults);
 

test/Microsoft.AspNetCore.Routing.Tests/Tree/TreeRouteBuilderTest.cs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Text.Encodings.Web;
-using Microsoft.AspNetCore.Routing.Internal;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Routing.Template;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.DependencyInjection;
@@ -244,7 +244,7 @@ namespace Microsoft.AspNetCore.Routing.Tree
         private static TreeRouteBuilder CreateBuilder()
         {
             var objectPoolProvider = new DefaultObjectPoolProvider();
-            var objectPolicy = new UriBuilderContextPooledObjectPolicy(UrlEncoder.Default);
+            var objectPolicy = new UriBuilderContextPooledObjectPolicy();
             var objectPool = objectPoolProvider.Create(objectPolicy);
 
             var constraintResolver = GetInlineConstraintResolver();

test/Microsoft.AspNetCore.Routing.Tests/Tree/TreeRouterTest.cs

@@ -6,8 +6,8 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Dispatcher;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Routing.Internal;
 using Microsoft.AspNetCore.Routing.Template;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -24,8 +24,7 @@ namespace Microsoft.AspNetCore.Routing.Tree
         private static readonly RequestDelegate NullHandler = (c) => Task.FromResult(0);
 
         private static UrlEncoder Encoder = UrlTestEncoder.Default;
-        private static ObjectPool<UriBuildingContext> Pool = new DefaultObjectPoolProvider().Create(
+        private static ObjectPool<UriBuildingContext> Pool = new DefaultObjectPoolProvider().Create(new UriBuilderContextPooledObjectPolicy());
-            new UriBuilderContextPooledObjectPolicy(Encoder));
 
         [Theory]
         [InlineData("template/5", "template/{parameter:int}")]
@@ -1990,7 +1989,7 @@ namespace Microsoft.AspNetCore.Routing.Tree
         private static TreeRouteBuilder CreateBuilder()
         {
             var objectPoolProvider = new DefaultObjectPoolProvider();
-            var objectPolicy = new UriBuilderContextPooledObjectPolicy(UrlEncoder.Default);
+            var objectPolicy = new UriBuilderContextPooledObjectPolicy();
             var objectPool = objectPoolProvider.Create<UriBuildingContext>(objectPolicy);
 
             var constraintResolver = CreateConstraintResolver();