Add LaunchForTextAsync (#591)

Author: SimonCropp

docs/diff-tool.order.md

@@ -51,5 +51,5 @@ For example `VisualStudio,Meld` will result in VisualStudio then Meld then all o
 ```cs
 DiffTools.UseOrder(DiffTool.VisualStudio, DiffTool.AraxisMerge);
 ```
-<sup><a href='/src/DiffEngine.Tests/DiffToolsTest.cs#L167-L171' title='Snippet source file'>snippet source</a> | <a href='#snippet-UseOrder' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/DiffEngine.Tests/DiffToolsTest.cs#L174-L178' title='Snippet source file'>snippet source</a> | <a href='#snippet-UseOrder' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->

src/DiffEngine.Tests/DiffToolsTest.cs

@@ -155,8 +155,15 @@ public Task TextFileConvention()
         var targetFile = Path.Combine(SourceDirectory, "input.target.txtConvention");
         return DiffRunner.LaunchAsync(tempFile, targetFile);
     }
-    **/
 
+    [Fact]
+    public Task LaunchForTextAsync()
+    {
+        var tempFile = Path.Combine(SourceDirectory, "input.temp.txtConvention");
+        var targetFile = Path.Combine(SourceDirectory, "input.target.txtConvention");
+        return DiffRunner.LaunchForTextAsync(tempFile, targetFile);
+    }
+    **/
     //todo: re enable tests with fake diff tool.
 
     /**

src/DiffEngine/DiffRunner.cs

@@ -64,6 +64,35 @@ public static Task<LaunchResult> LaunchAsync(string tempFile, string targetFile,
             targetFile,
             encoding);
     }
+    /// <summary>
+    /// Launch a diff tool for the given paths.
+    /// </summary>
+    public static Task<LaunchResult> LaunchForTextAsync(string tempFile, string targetFile, Encoding? encoding = null)
+    {
+        GuardFiles(tempFile, targetFile);
+
+        return InnerLaunchAsync(
+            ([NotNullWhen(true)] out ResolvedTool? tool) =>
+                DiffTools.TryFindForText(out tool),
+            tempFile,
+            targetFile,
+            encoding);
+    }
+
+    /// <summary>
+    /// Launch a diff tool for the given paths.
+    /// </summary>
+    public static LaunchResult LaunchForText(string tempFile, string targetFile, Encoding? encoding = null)
+    {
+        GuardFiles(tempFile, targetFile);
+
+        return InnerLaunch(
+            ([NotNullWhen(true)] out ResolvedTool? tool) =>
+                DiffTools.TryFindForText(out tool),
+            tempFile,
+            targetFile,
+            encoding);
+    }
 
     public static LaunchResult Launch(ResolvedTool tool, string tempFile, string targetFile, Encoding? encoding = null)
     {

src/DiffEngine/DiffTools_TryFind.cs

@@ -20,6 +20,12 @@ public static bool TryFindByExtension(
         return ExtensionLookup.TryGetValue(extension, out tool);
     }
 
+    public static bool TryFindForText([NotNullWhen(true)] out ResolvedTool? tool)
+    {
+        tool = resolved.FirstOrDefault(_ => _.SupportsText);
+        return tool != null;
+    }
+
     public static bool TryFindForInputFilePath(
         string path,
         [NotNullWhen(true)] out ResolvedTool? tool)

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;CS0649</NoWarn>
-    <Version>15.7.1</Version>
+    <Version>15.8.0</Version>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Testing, Snapshot, Diff, Compare</PackageTags>
     <Description>Launches diff tools based on file extensions. Designed to be consumed by snapshot testing libraries.</Description>