add special handeling of too long path's

src/NuGetForUnity/Editor/Helper/Md5HashHelper.cs

@@ -0,0 +1,49 @@
+#pragma warning disable SA1512,SA1124 // Single-line comments should not be followed by blank line
+
+#region No ReShaper
+
+using System;
+using System.Security.Cryptography;
+using System.Text;
+using JetBrains.Annotations;
+
+// ReSharper disable All
+// needed because 'JetBrains.Annotations.NotNull' and 'System.Diagnostics.CodeAnalysis.NotNull' collide if this file is compiled with a never version of Unity / C#
+using SuppressMessageAttribute = System.Diagnostics.CodeAnalysis.SuppressMessageAttribute;
+
+// ReSharper restore All
+
+#endregion
+
+#pragma warning restore SA1512,SA1124 // Single-line comments should not be followed by blank line
+
+namespace NugetForUnity.Helper
+{
+    /// <summary>
+    ///     Helper class for MD5 hashing.
+    /// </summary>
+    internal static class Md5HashHelper
+    {
+        /// <summary>
+        ///     Computes the MD5 hash of <paramref name="value" /> and returns it as Base64 string with all chars that are not allowed on file-paths replaced.
+        /// </summary>
+        /// <param name="value">The string that is hashed.</param>
+        /// <returns>The MD5 has of <paramref name="value" /> as a Base64 string with all chars that are not allowed on file-paths replaced.</returns>
+        /// <exception cref="ArgumentNullException">If <paramref name="value" /> is null or a empty string.</exception>
+        [SuppressMessage("Design", "CA5351", Justification = "Only use MD5 hash as cache key / not security relevant.")]
+        [NotNull]
+        public static string GetFileNameSafeHash([NotNull] string value)
+        {
+            if (string.IsNullOrEmpty(value))
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            using (var md5 = new MD5CryptoServiceProvider())
+            {
+                var data = md5.ComputeHash(Encoding.Default.GetBytes(value));
+                return Convert.ToBase64String(data).Replace('+', '-').Replace('/', '_').TrimEnd('=');
+            }
+        }
+    }
+}

src/NuGetForUnity/Editor/Helper/NugetPackageTextureHelper.cs

@@ -1,30 +1,14 @@
-#pragma warning disable SA1512,SA1124 // Single-line comments should not be followed by blank line
-
-#if UNITY_2022_1_OR_NEWER
+#if UNITY_2022_1_OR_NEWER
 using UnityEditor;
 #endif
 
 using System;
 using System.IO;
-using System.Security.Cryptography;
-using System.Text;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
 using UnityEngine;
 using UnityEngine.Networking;
 
-#region No ReShaper
-
-// ReSharper disable All
-// needed because 'JetBrains.Annotations.NotNull' and 'System.Diagnostics.CodeAnalysis.NotNull' collide if this file is compiled with a never version of Unity / C#
-using SuppressMessageAttribute = System.Diagnostics.CodeAnalysis.SuppressMessageAttribute;
-
-// ReSharper restore All
-
-#endregion
-
-#pragma warning restore SA1512,SA1124 // Single-line comments should not be followed by blank line
-
 namespace NugetForUnity.Helper
 {
     /// <summary>
@@ -129,23 +113,7 @@ private static void CacheTextureOnDisk([NotNull] string cacheFilePath, [NotNull]
         [NotNull]
         private static string GetCacheFilePath([NotNull] string url)
         {
-            return Path.Combine(Application.temporaryCachePath, GetHash(url));
-        }
-
-        [SuppressMessage("Design", "CA5351", Justification = "Only use MD5 hash as cache key / not security relevant.")]
-        [NotNull]
-        private static string GetHash([NotNull] string s)
-        {
-            if (string.IsNullOrEmpty(s))
-            {
-                throw new ArgumentNullException(nameof(s));
-            }
-
-            using (var md5 = new MD5CryptoServiceProvider())
-            {
-                var data = md5.ComputeHash(Encoding.Default.GetBytes(s));
-                return Convert.ToBase64String(data).Replace('+', '-').Replace('/', '_').TrimEnd('=');
-            }
+            return Path.Combine(Application.temporaryCachePath, Md5HashHelper.GetFileNameSafeHash(url));
         }
     }
 }

src/NuGetForUnity/Editor/PackageContentManager.cs

@@ -17,6 +17,8 @@ namespace NugetForUnity
     /// </summary>
     internal static class PackageContentManager
     {
+        private const int MaxPathLength = 260;
+
         /// <summary>
         ///     Deletes all files and folders associated with a package.
         /// </summary>
@@ -316,15 +318,31 @@ internal static string ExtractPackageEntry([NotNull] ZipArchiveEntry entry, [Not
                 return null;
             }
 
-            var directory = Path.GetDirectoryName(filePath) ?? throw new InvalidOperationException($"Failed to get directory name of '{filePath}'");
-            Directory.CreateDirectory(directory);
-            if (Directory.Exists(filePath))
+            try
             {
-                Debug.LogWarning($"The path {filePath} refers to an existing directory. Overwriting it may lead to data loss.");
-                return null;
+                if (Directory.Exists(filePath))
+                {
+                    Debug.LogWarning($"The path {filePath} refers to an existing directory. Overwriting it may lead to data loss.");
+                    return null;
+                }
+
+                var directory = Path.GetDirectoryName(filePath) ??
+                                throw new InvalidOperationException($"Failed to get directory name of '{filePath}'");
+                Directory.CreateDirectory(directory);
+
+                entry.ExtractToFile(filePath, true);
             }
+            catch (Exception exception) when (exception is PathTooLongException ||
+                                              (exception is DirectoryNotFoundException && filePath.Length >= MaxPathLength))
+            {
+                // path is to long (normally on windows) -> try to use shorter path
+                // we only do this when we get a exception because it can be that we are on a system that supports longer paths
+                var longFilePath = filePath;
+                filePath = DetermineShorterFilePath(entry, baseDir);
 
-            entry.ExtractToFile(filePath, true);
+                NugetLogger.LogVerbose("The target file path '{0}' was to long -> we shortened it to '{1}'.", longFilePath, filePath);
+                entry.ExtractToFile(filePath, true);
+            }
 
             if (filePath.EndsWith(".pdb", StringComparison.OrdinalIgnoreCase) && !PortableSymbolFileHelper.IsPortableSymbolFile(filePath))
             {
@@ -402,6 +420,26 @@ internal static void MoveInstalledPackages(string oldPath, string newPath)
             }
         }
 
+        private static string DetermineShorterFilePath(ZipArchiveEntry entry, string baseDir)
+        {
+            var filePath = Path.GetFullPath(Path.Combine(baseDir, entry.Name));
+            if (filePath.Length < MaxPathLength && !File.Exists(filePath))
+            {
+                // placing the file in the base-directory is enough to make the path usable.
+                return filePath;
+            }
+
+            filePath = Path.GetFullPath(Path.Combine(baseDir, Md5HashHelper.GetFileNameSafeHash(entry.FullName)));
+            if (filePath.Length + entry.Name.Length + 1 < MaxPathLength)
+            {
+                // we have enough space to keep the file name
+                return $"{filePath}_{entry.Name}";
+            }
+
+            // only add the file extension
+            return filePath + Path.GetExtension(entry.Name);
+        }
+
         [NotNull]
         private static string GetPackageOutsideInstallDirectory([NotNull] INugetPackageIdentifier package)
         {

src/NuGetForUnity/Editor/PackageSource/NugetPackageSourceV2.cs

@@ -443,6 +443,17 @@ public void OnAfterDeserialize()
             }
         }
 
+        private static void CopyIsManuallyInstalled(List<INugetPackage> newPackages, ICollection<INugetPackage> packagesToUpdate)
+        {
+            foreach (var newPackage in newPackages)
+            {
+                newPackage.IsManuallyInstalled =
+                    packagesToUpdate.FirstOrDefault(packageToUpdate => packageToUpdate.Id.Equals(newPackage.Id, StringComparison.OrdinalIgnoreCase))
+                        ?.IsManuallyInstalled ??
+                    false;
+            }
+        }
+
         /// <summary>
         ///     Builds a list of NugetPackages from the XML returned from the HTTP GET request issued at the given URL.
         ///     Note that NuGet uses an Atom-feed (XML Syndicaton) superset called OData.
@@ -519,16 +530,5 @@ private List<INugetPackage> GetUpdatesFallback(
             NugetLogger.LogVerbose("NugetPackageSource.GetUpdatesFallback took {0} ms", stopwatch.ElapsedMilliseconds);
             return updates;
         }
-
-        private static void CopyIsManuallyInstalled(List<INugetPackage> newPackages, ICollection<INugetPackage> packagesToUpdate)
-        {
-            foreach (var newPackage in newPackages)
-            {
-                newPackage.IsManuallyInstalled =
-                    packagesToUpdate.FirstOrDefault(packageToUpdate => packageToUpdate.Id.Equals(newPackage.Id, StringComparison.OrdinalIgnoreCase))
-                        ?.IsManuallyInstalled ??
-                    false;
-            }
-        }
     }
 }