Inline legacy local link parsing to drop obsolete HtmlLocalLinkParser API

uSync.Core/Versions/18.0/SyncLocalLinkProcessor.cs

@@ -1,11 +1,12 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Text;
+using System.Text.RegularExpressions;
 
 using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.Models;
 using Umbraco.Cms.Core.Services;
-using Umbraco.Cms.Core.Templates;
 
 namespace uSync.Core.Versions._18._0;
 
@@ -18,19 +19,27 @@ public interface ISyncTypedLocalLinkProcessor
     public Func<object?, Func<object?, bool>, Func<string, string>, bool> Process { get; }
 }
 
-
-public class SyncLocalLinkProcessor
+/// <summary>
+///  Finds and replaces the legacy {localLink:x} syntax within values, mapping ids/UDIs to keys.
+/// </summary>
+/// <remarks>
+///  Umbraco's own <c>HtmlLocalLinkParser.FindLegacyLocalLinkIds</c> (and its <c>LocalLinkTag</c> model)
+///  are obsolete and scheduled for removal in Umbraco 18, but uSync still needs to detect these
+///  legacy (un-migrated) links when mapping content, so the parsing logic lives here instead.
+/// </remarks>
+public partial class SyncLocalLinkProcessor
 {
-    private readonly HtmlLocalLinkParser _localLinkParser;
+    // copied from Umbraco.Cms.Core.Templates.HtmlLocalLinkParser.LocalLinkPattern
+    [GeneratedRegex(@"href=['""](?<locallink>\/?(?:\{|\%7B)localLink:(?<guid>[a-zA-Z0-9-://]+)(?:\}|\%7D))", RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace, "en-GB")]
+    private static partial Regex LegacyLocalLinkPattern();
+
     private readonly IIdKeyMap _idKeyMap;
     private readonly IEnumerable<ISyncTypedLocalLinkProcessor> _localLinkProcessors;
 
     public SyncLocalLinkProcessor(
-        HtmlLocalLinkParser localLinkParser,
         IIdKeyMap idKeyMap,
         IEnumerable<ISyncTypedLocalLinkProcessor> localLinkProcessors)
     {
-        _localLinkParser = localLinkParser;
         _idKeyMap = idKeyMap;
         _localLinkProcessors = localLinkProcessors;
     }
@@ -49,9 +58,9 @@ public bool ProcessToEditorValue(object? editorValue)
     public string ProcessStringValue(string input)
     {
         // find all legacy tags
-        var tags = _localLinkParser.FindLegacyLocalLinkIds(input).ToList();
+        var tags = FindLegacyLocalLinkIds(input).ToList();
 
-        foreach (HtmlLocalLinkParser.LocalLinkTag tag in tags)
+        foreach (LocalLinkTag tag in tags)
         {
             string newTagHref;
             if (tag.Udi is not null)
@@ -101,4 +110,49 @@ public string ProcessStringValue(string input)
         return null;
     }
 
+    // copied from Umbraco.Cms.Core.Templates.HtmlLocalLinkParser.FindLegacyLocalLinkIds
+    private static IEnumerable<LocalLinkTag> FindLegacyLocalLinkIds(string text)
+    {
+        MatchCollection tags = LegacyLocalLinkPattern().Matches(text);
+        foreach (Match tag in tags)
+        {
+            if (tag.Groups.Count <= 0)
+            {
+                continue;
+            }
+
+            var id = tag.Groups["guid"].Value;
+
+            // The id could be an int or a UDI
+            if (UdiParser.TryParse(id, out Udi? udi))
+            {
+                if (udi is GuidUdi guidUdi)
+                {
+                    yield return new LocalLinkTag(null, guidUdi, tag.Groups["locallink"].Value);
+                }
+            }
+
+            if (int.TryParse(id, NumberStyles.Integer, CultureInfo.InvariantCulture, out var intId))
+            {
+                yield return new LocalLinkTag(intId, null, tag.Groups["locallink"].Value);
+            }
+        }
+    }
+
+    // copied from Umbraco.Cms.Core.Templates.HtmlLocalLinkParser.LocalLinkTag
+    private sealed class LocalLinkTag
+    {
+        public LocalLinkTag(int? intId, GuidUdi? udi, string tagHref)
+        {
+            IntId = intId;
+            Udi = udi;
+            TagHref = tagHref;
+        }
+
+        public int? IntId { get; }
+
+        public GuidUdi? Udi { get; }
+
+        public string TagHref { get; }
+    }
 }