#258 Updates LinkBuilder, RelatedAttrFilterQuery, RequestMiddleware, JsonApiContext, and QueryParser to utilize new SpanSplitter library to avoid unnecessary intermediate string creation.

Corey Floyd · Corey Floyd · commit 99369397b7bd · 2018-04-24T13:20:19.000-05:00
diff --git a/src/JsonApiDotNetCore/Builders/LinkBuilder.cs b/src/JsonApiDotNetCore/Builders/LinkBuilder.cs
@@ -1,3 +1,6 @@
+using System;
+using System.Text;
+using JsonApiDotNetCore.Internal;
 using JsonApiDotNetCore.Services;
 using Microsoft.AspNetCore.Http;
 
@@ -20,20 +23,18 @@ public string GetBasePath(HttpContext context, string entityName)
                 : $"{r.Scheme}://{r.Host}{GetNamespaceFromPath(r.Path, entityName)}";
         }
 
-        private string GetNamespaceFromPath(string path, string entityName)
+        private static string GetNamespaceFromPath(string path, string entityName)
         {
-            var nSpace = string.Empty;
-            var segments = path.Split('/');
-
-            for (var i = 1; i < segments.Length; i++)
+            var sb = new StringBuilder();
+            var entityNameSpan = entityName.AsSpan();
+            var subSpans = new SpanSplitter(ref path, '/');
+            for (var i = 1; i < subSpans.Count; i++)
             {
-                if (segments[i].ToLower() == entityName)
-                    break;
-
-                nSpace += $"/{segments[i]}";
+                var span = subSpans[i];
+                if (entityNameSpan.SequenceEqual(span)) break;
+                sb.Append($"/{span.ToString()}");
             }
-
-            return nSpace;
+            return sb.ToString();
         }
 
         public string GetSelfRelationLink(string parent, string parentId, string child)
diff --git a/src/JsonApiDotNetCore/Extensions/StringExtensions.cs b/src/JsonApiDotNetCore/Extensions/StringExtensions.cs
@@ -1,3 +1,5 @@
+using System;
+using System.Collections.Generic;
 using System.Text;
 
 namespace JsonApiDotNetCore.Extensions
@@ -50,5 +52,16 @@ public static string Dasherize(this string str)
             }
             return str;
         }
+
+        public static IEnumerable<int> IndexesOf(this string str, char delimeter)
+        {
+            var indexes = new List<int>();
+            for (var i = str.IndexOf(delimeter); i > -1 ; i = str.IndexOf(delimeter, i+1))
+            {
+                indexes.Add(i);
+            }
+            return indexes;
+        }
+        
     }
 }
diff --git a/src/JsonApiDotNetCore/Internal/Query/RelatedAttrFilterQuery.cs b/src/JsonApiDotNetCore/Internal/Query/RelatedAttrFilterQuery.cs
@@ -8,20 +8,21 @@ namespace JsonApiDotNetCore.Internal.Query
     public class RelatedAttrFilterQuery : BaseFilterQuery
     {
         private readonly IJsonApiContext _jsonApiContext;
-
+        
         public RelatedAttrFilterQuery(
             IJsonApiContext jsonApiCopntext,
             FilterQuery filterQuery)
         {
             _jsonApiContext = jsonApiCopntext;
-
-            var relationshipArray = filterQuery.Attribute.Split('.');
-
-            var relationship = GetRelationship(relationshipArray[0]);
+            var filterQueryAttribute = filterQuery.Attribute;
+            var relationshipSubSpans = new SpanSplitter(ref filterQueryAttribute, '.');
+            var relationship1 = relationshipSubSpans[0].ToString();
+            var relationship2 = relationshipSubSpans[1].ToString();
+            var relationship = GetRelationship(relationshipSubSpans[0].ToString());
             if (relationship == null)
-                throw new JsonApiException(400, $"{relationshipArray[1]} is not a valid relationship on {relationshipArray[0]}.");
+                throw new JsonApiException(400, $"{relationship2} is not a valid relationship on {relationship1}.");
 
-            var attribute = GetAttribute(relationship, relationshipArray[1]);
+            var attribute = GetAttribute(relationship, relationship2);
 
             if (attribute == null)
                 throw new JsonApiException(400, $"'{filterQuery.Attribute}' is not a valid attribute.");
diff --git a/src/JsonApiDotNetCore/Middleware/RequestMiddleware.cs b/src/JsonApiDotNetCore/Middleware/RequestMiddleware.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Threading.Tasks;
 using JsonApiDotNetCore.Internal;
 using Microsoft.AspNetCore.Http;
@@ -54,8 +55,11 @@ private static bool IsValidAcceptHeader(HttpContext context)
 
         private static bool ContainsMediaTypeParameters(string mediaType)
         {
-            var mediaTypeArr = mediaType.Split(';');
-            return (mediaTypeArr[0] ==  Constants.ContentType && mediaTypeArr.Length == 2);
+            const char delimeter = ';';
+            var sliceLength = mediaType.IndexOf(delimeter);
+            if (sliceLength < 0) return false;
+            var mediaTypeSlice = mediaType.AsSpan().Slice(0, sliceLength);
+            return mediaTypeSlice.Length == 2 && mediaTypeSlice.SequenceEqual(Constants.ContentType.AsSpan());
         }
 
         private static void FlushResponse(HttpContext context, int statusCode)
diff --git a/src/JsonApiDotNetCore/Services/JsonApiContext.cs b/src/JsonApiDotNetCore/Services/JsonApiContext.cs
@@ -64,7 +64,7 @@ public IJsonApiContext ApplyContext<T>(object controller)
                 throw new JsonApiException(500, $"A resource has not been properly defined for type '{typeof(T)}'. Ensure it has been registered on the ContextGraph.");
 
             var context = _httpContextAccessor.HttpContext;
-            var path = context.Request.Path.Value.Split('/');
+            var requestPath = context.Request.Path.Value;
 
             if (context.Request.Query.Count > 0)
             {
@@ -75,10 +75,13 @@ public IJsonApiContext ApplyContext<T>(object controller)
             var linkBuilder = new LinkBuilder(this);
             BasePath = linkBuilder.GetBasePath(context, _controllerContext.RequestEntity.EntityName);
             PageManager = GetPageManager();
-            IsRelationshipPath = path[path.Length - 2] == "relationships";
+
+            var pathSpans = new SpanSplitter(ref requestPath, '/');
+            IsRelationshipPath = pathSpans[pathSpans.Count - 2].ToString() == "relationships";
+
             return this;
         }
-
+        
         private PageManager GetPageManager()
         {
             if (Options.DefaultPageSize == 0 && (QuerySet == null || QuerySet.PageQuery.PageSize == 0))
diff --git a/src/JsonApiDotNetCore/Services/QueryParser.cs b/src/JsonApiDotNetCore/Services/QueryParser.cs
@@ -3,6 +3,7 @@
 using System.Linq;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Controllers;
+using JsonApiDotNetCore.Extensions;
 using JsonApiDotNetCore.Internal;
 using JsonApiDotNetCore.Internal.Query;
 using JsonApiDotNetCore.Models;
@@ -93,16 +94,16 @@ protected virtual List<FilterQuery> ParseFilterQuery(string key, string value)
             // expected input = filter[id]=1
             // expected input = filter[id]=eq:1
             var queries = new List<FilterQuery>();
+            var openBracketIndex = key.IndexOf(OPEN_BRACKET);
+            var closedBracketIndex = key.IndexOf(CLOSE_BRACKET);
+            var propertyNameSlice = key.AsSpan().Slice(openBracketIndex + 1, closedBracketIndex - openBracketIndex - 1);
+            var propertyName = propertyNameSlice.ToString();
 
-            var propertyName = key.Split(OPEN_BRACKET, CLOSE_BRACKET)[1];
-
-            var values = value.Split(COMMA);
-            foreach (var val in values)
+            var spanSplitter = new SpanSplitter(ref value, COMMA);
+            for (var i = 0; i < spanSplitter.Count; i++)
             {
-                (var operation, var filterValue) = ParseFilterOperation(val);
-                queries.Add(new FilterQuery(propertyName, filterValue, operation));
+                queries.Add(BuildFilterQuery(spanSplitter[i], propertyName));
             }
-
             return queries;
         }
 
@@ -235,5 +236,11 @@ protected virtual AttrAttribute GetAttribute(string propertyName)
                 throw new JsonApiException(400, $"Attribute '{propertyName}' does not exist on resource '{_controllerContext.RequestEntity.EntityName}'", e);
             }
         }
+
+        private FilterQuery BuildFilterQuery(ReadOnlySpan<char> query, string propertyName)
+        {
+            var (operation, filterValue) = ParseFilterOperation(query.ToString());
+            return new FilterQuery(propertyName, filterValue, operation);
+        }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+using System;`
	`2`	`+using System.Collections.Generic;`
`1`	`3`	`using System.Text;`
`2`	`4`
`3`	`5`	`namespace JsonApiDotNetCore.Extensions`
`@@ -50,5 +52,16 @@ public static string Dasherize(this string str)`
`50`	`52`	`}`
`51`	`53`	`return str;`
`52`	`54`	`}`
	`55`	`+`
	`56`	`+ public static IEnumerable<int> IndexesOf(this string str, char delimeter)`
	`57`	`+ {`
	`58`	`+ var indexes = new List<int>();`
	`59`	`+ for (var i = str.IndexOf(delimeter); i > -1 ; i = str.IndexOf(delimeter, i+1))`
	`60`	`+ {`
	`61`	`+ indexes.Add(i);`
	`62`	`+ }`
	`63`	`+ return indexes;`
	`64`	`+ }`
	`65`	`+`
`53`	`66`	`}`
`54`	`67`	`}`