UsePatienceAlgorithm flag in CompareOptions, closes#1037

Author: dmalikov

LibGit2Sharp.Tests/DiffTreeToTreeFixture.cs

@@ -1133,5 +1133,75 @@ public void CallingCompareWithAnUnsupportedGenericParamThrows()
 Assert.Throws<LibGit2SharpException>(()=>repo.Diff.Compare<string>());
 }
 }
+
+[Fact]
+publicvoidUsingPatienceAlgorithmCompareOptionProducesPatienceDiff()
+{
+stringrepoPath=InitNewRepository();
+using(varrepo=newRepository(repoPath))
+{
+Func<string,Tree>fromString=
+ s =>
+repo.ObjectDatabase.CreateTree(newTreeDefinition().Add("file.txt",
+OdbHelper.CreateBlob(repo,s),Mode.NonExecutableFile));
+
+TreetreeOld=fromString(newStringBuilder()
+.Append("aaaaaa\n")
+.Append("aaaaaa\n")
+.Append("bbbbbb\n")
+.Append("bbbbbb\n")
+.Append("cccccc\n")
+.Append("cccccc\n")
+.Append("abc\n").ToString());
+
+TreetreeNew=fromString(newStringBuilder()
+.Append("abc\n")
+.Append("aaaaaa\n")
+.Append("aaaaaa\n")
+.Append("bbbbbb\n")
+.Append("bbbbbb\n")
+.Append("cccccc\n")
+.Append("cccccc\n").ToString());
+
+stringdiffDefault=newStringBuilder()
+.Append("diff --git a/file.txt b/file.txt\n")
+.Append("index 3299d68..accc3bd 100644\n")
+.Append("--- a/file.txt\n")
+.Append("+++ b/file.txt\n")
+.Append("@@ -1,7 +1,7 @@\n")
+.Append("+abc\n")
+.Append(" aaaaaa\n")
+.Append(" aaaaaa\n")
+.Append(" bbbbbb\n")
+.Append(" bbbbbb\n")
+.Append(" cccccc\n")
+.Append(" cccccc\n")
+.Append("-abc\n").ToString();
+
+stringdiffPatience=newStringBuilder()
+.Append("diff --git a/file.txt b/file.txt\n")
+.Append("index 3299d68..accc3bd 100644\n")
+.Append("--- a/file.txt\n")
+.Append("+++ b/file.txt\n")
+.Append("@@ -1,7 +1,7 @@\n")
+.Append("-aaaaaa\n")
+.Append("-aaaaaa\n")
+.Append("-bbbbbb\n")
+.Append("-bbbbbb\n")
+.Append("-cccccc\n")
+.Append("-cccccc\n")
+.Append(" abc\n")
+.Append("+aaaaaa\n")
+.Append("+aaaaaa\n")
+.Append("+bbbbbb\n")
+.Append("+bbbbbb\n")
+.Append("+cccccc\n")
+.Append("+cccccc\n").ToString();
+
+Assert.Equal(diffDefault,repo.Diff.Compare<Patch>(treeOld,treeNew));
+Assert.Equal(diffPatience,repo.Diff.Compare<Patch>(treeOld,treeNew,
+compareOptions:newCompareOptions{UsePatienceAlgorithm=true}));
+}
+}
 }
 }

LibGit2Sharp/CompareOptions.cs

@@ -35,5 +35,10 @@ public CompareOptions()
 /// Include "unmodified" entries in the results.
 /// </summary>
 publicboolIncludeUnmodified{get;set;}
+
+/// <summary>
+/// Use the "patience diff" algorithm.
+/// </summary>
+publicboolUsePatienceAlgorithm{get;set;}
 }
 }

LibGit2Sharp/Diff.cs

@@ -49,6 +49,11 @@ private static GitDiffOptions BuildOptions(DiffModifiers diffOptions, FilePath[]
 options.Flags|=GitDiffOptionFlags.GIT_DIFF_INCLUDE_UNMODIFIED;
 }
 
+if(compareOptions.UsePatienceAlgorithm)
+{
+options.Flags|=GitDiffOptionFlags.GIT_DIFF_PATIENCE;
+}
+
 if(diffOptions.HasFlag(DiffModifiers.DisablePathspecMatch))
 {
 options.Flags|=GitDiffOptionFlags.GIT_DIFF_DISABLE_PATHSPEC_MATCH;