From 73c4e734b35aac3903a520a91d6882c266614bba Mon Sep 17 00:00:00 2001
From: Stephan <stephane@umbraco.dk>
Date: Thu, 21 Feb 2019 12:20:10 +0100
Subject: [PATCH] Move to UniqueMediaPathScheme

---
 .../CompositionExtensions/FileSystems.cs      |  2 +-
 .../CombinedGuidsMediaPathScheme.cs           |  1 +
 .../MediaPathSchemes/UniqueMediaPathScheme.cs | 38 +++++++++++++++++++
 src/Umbraco.Core/Umbraco.Core.csproj          |  1 +
 src/Umbraco.Tests/IO/FileSystemsTests.cs      |  2 +-
 src/Umbraco.Tests/Testing/UmbracoTestBase.cs  |  2 +-
 6 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 src/Umbraco.Core/IO/MediaPathSchemes/UniqueMediaPathScheme.cs

diff --git a/src/Umbraco.Core/Composing/CompositionExtensions/FileSystems.cs b/src/Umbraco.Core/Composing/CompositionExtensions/FileSystems.cs
index 4fbbec0265..078a505be9 100644
--- a/src/Umbraco.Core/Composing/CompositionExtensions/FileSystems.cs
+++ b/src/Umbraco.Core/Composing/CompositionExtensions/FileSystems.cs
@@ -79,7 +79,7 @@ namespace Umbraco.Core.Composing.CompositionExtensions
             composition.RegisterUnique<IFileSystems>(factory => factory.GetInstance<IO.FileSystems>());
 
             // register the scheme for media paths
-            composition.RegisterUnique<IMediaPathScheme, CombinedGuidsMediaPathScheme>();
+            composition.RegisterUnique<IMediaPathScheme, UniqueMediaPathScheme>();
 
             // register the IMediaFileSystem implementation
             composition.RegisterFileSystem<IMediaFileSystem, MediaFileSystem>();
diff --git a/src/Umbraco.Core/IO/MediaPathSchemes/CombinedGuidsMediaPathScheme.cs b/src/Umbraco.Core/IO/MediaPathSchemes/CombinedGuidsMediaPathScheme.cs
index fa5ec12142..8a4c0e5dc0 100644
--- a/src/Umbraco.Core/IO/MediaPathSchemes/CombinedGuidsMediaPathScheme.cs
+++ b/src/Umbraco.Core/IO/MediaPathSchemes/CombinedGuidsMediaPathScheme.cs
@@ -8,6 +8,7 @@ namespace Umbraco.Core.IO.MediaPathSchemes
     /// </summary>
     /// <remarks>
     /// <para>Path is "{combinedGuid}/{filename}" where combinedGuid is a combination of itemGuid and propertyGuid.</para>
+    /// <para>This scheme is dangerous, as it does not prevent potential collisions.</para>
     /// </remarks>
     public class CombinedGuidsMediaPathScheme : IMediaPathScheme
     {
diff --git a/src/Umbraco.Core/IO/MediaPathSchemes/UniqueMediaPathScheme.cs b/src/Umbraco.Core/IO/MediaPathSchemes/UniqueMediaPathScheme.cs
new file mode 100644
index 0000000000..722c92d3de
--- /dev/null
+++ b/src/Umbraco.Core/IO/MediaPathSchemes/UniqueMediaPathScheme.cs
@@ -0,0 +1,38 @@
+using System;
+using System.IO;
+
+namespace Umbraco.Core.IO.MediaPathSchemes
+{
+    /// <summary>
+    /// Implements a unique directory media path scheme.
+    /// </summary>
+    /// <remarks>
+    /// <para>This scheme provides short paths, yet handle potential collisions.</para>
+    /// </remarks>
+    public class UniqueMediaPathScheme : IMediaPathScheme
+    {
+        private const int DirectoryLength = 8;
+
+        /// <inheritdoc />
+        public string GetFilePath(IMediaFileSystem fileSystem, Guid itemGuid, Guid propertyGuid, string filename, string previous = null)
+        {
+            string directory;
+
+            // no point "combining" guids if all we want is some random guid - just get a new one
+            // and then, because we don't want collisions, ensure that the directory does not already exist
+            // (should be quite rare, but eh...)
+
+            do
+            {
+                var combinedGuid = Guid.NewGuid();
+                directory = GuidUtils.ToBase32String(combinedGuid, DirectoryLength); // see also HexEncoder, we may want to fragment path eg 12/e4/f3...
+
+            } while (fileSystem.DirectoryExists(directory));
+
+            return Path.Combine(directory, filename).Replace('\\', '/');
+        }
+
+        /// <inheritdoc />
+        public string GetDeleteDirectory(IMediaFileSystem fileSystem, string filepath) => Path.GetDirectoryName(filepath);
+    }
+}
\ No newline at end of file
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index c3fe7be10a..d07c2e54eb 100755
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -205,6 +205,7 @@
     <Compile Include="Composing\TypeFinder.cs" />
     <Compile Include="Composing\TypeHelper.cs" />
     <Compile Include="Composing\TypeLoader.cs" />
+    <Compile Include="IO\MediaPathSchemes\UniqueMediaPathScheme.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\MergeDateAndDateTimePropertyEditor.cs" />
     <Compile Include="PropertyEditors\DateTimeConfiguration.cs" />
     <Compile Include="Migrations\Upgrade\V_8_0_0\RenameLabelAndRichTextPropertyEditorAliases.cs" />
diff --git a/src/Umbraco.Tests/IO/FileSystemsTests.cs b/src/Umbraco.Tests/IO/FileSystemsTests.cs
index 1f0250c066..d4124530ba 100644
--- a/src/Umbraco.Tests/IO/FileSystemsTests.cs
+++ b/src/Umbraco.Tests/IO/FileSystemsTests.cs
@@ -33,7 +33,7 @@ namespace Umbraco.Tests.IO
             composition.Register(_ => Mock.Of<ILogger>());
             composition.Register(_ => Mock.Of<IDataTypeService>());
             composition.Register(_ => Mock.Of<IContentSection>());
-            composition.RegisterUnique<IMediaPathScheme, CombinedGuidsMediaPathScheme>();
+            composition.RegisterUnique<IMediaPathScheme, UniqueMediaPathScheme>();
 
             composition.Configs.Add(SettingsForTests.GetDefaultGlobalSettings);
             composition.Configs.Add(SettingsForTests.GetDefaultUmbracoSettings);
diff --git a/src/Umbraco.Tests/Testing/UmbracoTestBase.cs b/src/Umbraco.Tests/Testing/UmbracoTestBase.cs
index 8fb8984fea..fedc94d45b 100644
--- a/src/Umbraco.Tests/Testing/UmbracoTestBase.cs
+++ b/src/Umbraco.Tests/Testing/UmbracoTestBase.cs
@@ -243,7 +243,7 @@ namespace Umbraco.Tests.Testing
             Composition.WithCollectionBuilder<PropertyValueConverterCollectionBuilder>();
             Composition.RegisterUnique<IPublishedContentTypeFactory, PublishedContentTypeFactory>();
 
-            Composition.RegisterUnique<IMediaPathScheme, CombinedGuidsMediaPathScheme>();
+            Composition.RegisterUnique<IMediaPathScheme, UniqueMediaPathScheme>();
 
             // register empty content apps collection
             Composition.WithCollectionBuilder<ContentAppFactoryCollectionBuilder>();