Merge pull request #878 from atravita-mods/develop

Rewrite asset name comparison to stop at the first mismatch

src/SMAPI.Tests/Core/AssetNameTests.cs

@@ -151,6 +151,12 @@ namespace SMAPI.Tests.Core
 
         // with locale codes
         [TestCase("Data/Achievements.fr-FR", "Data/Achievements", ExpectedResult = true)]
+
+        // prefix ends with path separator
+        [TestCase("Data/Events/Boop", "Data/Events/", ExpectedResult = true)]
+        [TestCase("Data/Events/Boop", "Data/Events\\", ExpectedResult = true)]
+        [TestCase("Data/Events", "Data/Events/", ExpectedResult = false)]
+        [TestCase("Data/Events", "Data/Events\\", ExpectedResult = false)]
         public bool StartsWith_SimpleCases(string mainAssetName, string prefix)
         {
             // arrange
@@ -243,6 +249,22 @@ namespace SMAPI.Tests.Core
             return result;
         }
 
+        [TestCase("Mods/SomeMod/SomeSubdirectory", "Mods/Some", true, ExpectedResult = true)]
+        [TestCase("Mods/SomeMod/SomeSubdirectory", "Mods/Some", false, ExpectedResult = false)]
+        [TestCase("Mods/Jasper/Data", "Mods/Jas/Image", true, ExpectedResult = false)]
+        [TestCase("Mods/Jasper/Data", "Mods/Jas/Image", true, ExpectedResult = false)]
+        public bool StartsWith_PartialMatchInPathSegment(string mainAssetName, string otherAssetName, bool allowSubfolder)
+        {
+            // arrange
+            mainAssetName = PathUtilities.NormalizeAssetName(mainAssetName);
+
+            // act
+            AssetName name = AssetName.Parse(mainAssetName, _ => null);
+
+            // assert value
+            return name.StartsWith(otherAssetName, allowPartialWord: true, allowSubfolder: allowSubfolder);
+        }
+
 
         /****
         ** GetHashCode

src/SMAPI/Framework/Content/AssetName.cs

@@ -1,6 +1,8 @@
 using System;
 using StardewModdingAPI.Toolkit.Utilities;
+using StardewModdingAPI.Utilities.AssetPathUtilities;
 using StardewValley;
+using ToolkitPathUtilities = StardewModdingAPI.Toolkit.Utilities.PathUtilities;
 
 namespace StardewModdingAPI.Framework.Content
 {
@@ -94,10 +96,26 @@ namespace StardewModdingAPI.Framework.Content
             if (string.IsNullOrWhiteSpace(assetName))
                 return false;
 
-            assetName = PathUtilities.NormalizeAssetName(assetName);
+            AssetNamePartEnumerator curParts = new(useBaseName ? this.BaseName : this.Name);
+            AssetNamePartEnumerator otherParts = new(assetName.AsSpan().Trim());
 
-            string compareTo = useBaseName ? this.BaseName : this.Name;
+            while (true)
-            return compareTo.Equals(assetName, StringComparison.OrdinalIgnoreCase);
+            {
+                bool curHasMore = curParts.MoveNext();
+                bool otherHasMore = otherParts.MoveNext();
+
+                // mismatch: lengths differ
+                if (otherHasMore != curHasMore)
+                    return false;
+
+                // match: both reached the end without a mismatch
+                if (!curHasMore)
+                    return true;
+
+                // mismatch: current segment is different
+                if (!curParts.Current.Equals(otherParts.Current, StringComparison.OrdinalIgnoreCase))
+                    return false;
+            }
         }
 
         /// <inheritdoc />
@@ -119,50 +137,78 @@ namespace StardewModdingAPI.Framework.Content
             if (prefix is null)
                 return false;
 
-            string rawTrimmed = prefix.Trim();
+            // get initial values
+            ReadOnlySpan<char> trimmedPrefix = prefix.AsSpan().Trim();
+            if (trimmedPrefix.Length == 0)
+                return true;
+            ReadOnlySpan<char> pathSeparators = new(ToolkitPathUtilities.PossiblePathSeparators); // just to simplify calling other span APIs
 
-            // asset keys can't have a leading slash, but NormalizeAssetName will trim them
+            // asset keys can't have a leading slash, but AssetPathYielder will trim them
-            if (rawTrimmed.StartsWith('/') || rawTrimmed.StartsWith('\\'))
+            if (pathSeparators.Contains(trimmedPrefix[0]))
                 return false;
 
-            // normalize prefix
+            // compare segments
+            AssetNamePartEnumerator curParts = new(this.Name);
+            AssetNamePartEnumerator prefixParts = new(trimmedPrefix);
+            while (true)
             {
-                string normalized = PathUtilities.NormalizeAssetName(prefix);
+                bool curHasMore = curParts.MoveNext();
+                bool prefixHasMore = prefixParts.MoveNext();
 
-                // keep trailing slash
+                // reached end for one side
-                if (rawTrimmed.EndsWith('/') || rawTrimmed.EndsWith('\\'))
+                if (prefixHasMore != curHasMore)
-                    normalized += PathUtilities.PreferredAssetSeparator;
+                {
+                    // mismatch: prefix is longer
+                    if (prefixHasMore)
+                        return false;
 
-                prefix = normalized;
+                    // match if subfolder paths are fine (e.g. prefix 'Data/Events' with target 'Data/Events/Beach')
+                    return allowSubfolder;
+                }
+
+                // previous segments matched exactly and both reached the end
+                // match if prefix doesn't end with '/' (which should only match subfolders)
+                if (!prefixHasMore)
+                    return !pathSeparators.Contains(trimmedPrefix[^1]);
+
+                // compare segment
+                if (curParts.Current.Length == prefixParts.Current.Length)
+                {
+                    // mismatch: segments aren't equivalent
+                    if (!curParts.Current.Equals(prefixParts.Current, StringComparison.OrdinalIgnoreCase))
+                        return false;
+                }
+                else
+                {
+                    // mismatch: prefix has more beyond this, and this segment isn't an exact match
+                    if (prefixParts.Remainder.Length != 0)
+                        return false;
+
+                    // mismatch: cur segment doesn't start with prefix
+                    if (!curParts.Current.StartsWith(prefixParts.Current, StringComparison.OrdinalIgnoreCase))
+                        return false;
+
+                    // mismatch: something like "Maps/" would need an exact match
+                    if (pathSeparators.Contains(trimmedPrefix[^1]))
+                        return false;
+
+                    // mismatch: partial word match not allowed, and the first or last letter of the suffix isn't a word separator
+                    if (!allowPartialWord && char.IsLetterOrDigit(prefixParts.Current[^1]) && char.IsLetterOrDigit(curParts.Current[prefixParts.Current.Length]))
+                        return false;
+
+                    // possible match
+                    return allowSubfolder || (pathSeparators.Contains(trimmedPrefix[^1]) ? curParts.Remainder.IndexOfAny(ToolkitPathUtilities.PossiblePathSeparators) < 0 : curParts.Remainder.Length == 0);
+                }
             }
-
-            // compare
-            if (prefix.Length == 0)
-                return true;
-
-            return
-                this.Name.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)
-                && (
-                    allowPartialWord
-                    || this.Name.Length == prefix.Length
-                    || !char.IsLetterOrDigit(prefix[^1]) // last character in suffix is word separator
-                    || !char.IsLetterOrDigit(this.Name[prefix.Length]) // or first character after it is
-                )
-                && (
-                    allowSubfolder
-                    || this.Name.Length == prefix.Length
-                    || !this.Name[prefix.Length..].Contains(PathUtilities.PreferredAssetSeparator)
-                );
         }
 
-
         /// <inheritdoc />
         public bool IsDirectlyUnderPath(string? assetFolder)
         {
             if (assetFolder is null)
                 return false;
 
-            return this.StartsWith(assetFolder + "/", allowPartialWord: false, allowSubfolder: false);
+            return this.StartsWith(assetFolder + ToolkitPathUtilities.PreferredPathSeparator, allowPartialWord: false, allowSubfolder: false);
         }
 
         /// <inheritdoc />

src/SMAPI/Utilities/AssetPathUtilities/AssetNamePartEnumerator.cs

@@ -0,0 +1,70 @@
+using System;
+using ToolkitPathUtilities = StardewModdingAPI.Toolkit.Utilities.PathUtilities;
+
+namespace StardewModdingAPI.Utilities.AssetPathUtilities
+{
+    /// <summary>Handles enumerating the normalized segments in an asset name.</summary>
+    internal ref struct AssetNamePartEnumerator
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The backing field for <see cref="Remainder"/>.</summary>
+        private ReadOnlySpan<char> RemainderImpl;
+
+
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The remainder of the asset name being enumerated, ignoring segments which have already been yielded.</summary>
+        public ReadOnlySpan<char> Remainder => this.RemainderImpl;
+
+        /// <summary>Get the current segment.</summary>
+        public ReadOnlySpan<char> Current { get; private set; } = default;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="assetName">The asset name to enumerate.</param>
+        public AssetNamePartEnumerator(ReadOnlySpan<char> assetName)
+        {
+            this.RemainderImpl = AssetNamePartEnumerator.TrimLeadingPathSeparators(assetName);
+        }
+
+        /// <summary>Move the enumerator to the next segment.</summary>
+        /// <returns>Returns true if a new value was found (accessible via <see cref="Current"/>).</returns>
+        public bool MoveNext()
+        {
+            if (this.RemainderImpl.Length == 0)
+                return false;
+
+            int index = this.RemainderImpl.IndexOfAny(ToolkitPathUtilities.PossiblePathSeparators);
+
+            // no more separator characters found, I'm done.
+            if (index < 0)
+            {
+                this.Current = this.RemainderImpl;
+                this.RemainderImpl = ReadOnlySpan<char>.Empty;
+                return true;
+            }
+
+            // Yield the next separate character bit
+            this.Current = this.RemainderImpl[..index];
+            this.RemainderImpl = AssetNamePartEnumerator.TrimLeadingPathSeparators(this.RemainderImpl[(index + 1)..]);
+            return true;
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Trim path separators at the start of the given path or segment.</summary>
+        /// <param name="span">The path or segment to trim.</param>
+        private static ReadOnlySpan<char> TrimLeadingPathSeparators(ReadOnlySpan<char> span)
+        {
+            return span.TrimStart(new ReadOnlySpan<char>(ToolkitPathUtilities.PossiblePathSeparators));
+        }
+    }
+}