Improve performance of refs.ReachableFrom()

nulltoken · nulltoken · commit abb358729f01 · 2014-04-11T16:15:04.000+02:00
diff --git a/LibGit2Sharp/Core/NativeMethods.cs b/LibGit2Sharp/Core/NativeMethods.cs
@@ -496,6 +496,12 @@ internal static extern int git_diff_find_similar(
         [DllImport(libgit2)]
         internal static extern int git_graph_ahead_behind(out UIntPtr ahead, out UIntPtr behind, RepositorySafeHandle repo, ref GitOid one, ref GitOid two);
 
+        [DllImport(libgit2)]
+        internal static extern int git_graph_descendant_of(
+            RepositorySafeHandle repo,
+            ref GitOid commit,
+            ref GitOid ancestor);
+
         [DllImport(libgit2)]
         internal static extern int git_ignore_add_rule(
             RepositorySafeHandle repo,
diff --git a/LibGit2Sharp/Core/Proxy.cs b/LibGit2Sharp/Core/Proxy.cs
@@ -754,6 +754,21 @@ public static GitDiffDelta git_diff_get_delta(DiffSafeHandle diff, int idx)
             }
         }
 
+        public static bool git_graph_descendant_of(RepositorySafeHandle repo, ObjectId commitId, ObjectId ancestorId)
+        {
+            GitOid oid1 = commitId.Oid;
+            GitOid oid2 = ancestorId.Oid;
+
+            using (ThreadAffinity())
+            {
+                int res = NativeMethods.git_graph_descendant_of(repo, ref oid1, ref oid2);
+
+                Ensure.BooleanResult(res);
+
+                return (res == 1);
+            }
+        }
+
         #endregion
 
         #region git_ignore_
diff --git a/LibGit2Sharp/ReferenceCollectionExtensions.cs b/LibGit2Sharp/ReferenceCollectionExtensions.cs
@@ -295,27 +295,40 @@ public static IEnumerable<Reference> ReachableFrom(
                 return Enumerable.Empty<Reference>();
             }
 
-            var targetsSet = new HashSet<Commit>(targets);
+            List<ObjectId> targetsSet = targets.Select(c => c.Id).Distinct().ToList();
             if (targetsSet.Count == 0)
             {
                 return Enumerable.Empty<Reference>();
             }
 
-            var allCommits = refsColl.repo.Commits;
-
             var result = new List<Reference>();
 
             foreach (var reference in refs)
             {
-                foreach (var commit in allCommits.QueryBy(new CommitFilter { Since = reference }))
+                var peeledTargetCommit = reference
+                                            .ResolveToDirectReference()
+                                            .Target.DereferenceToCommit(false);
+
+                if (peeledTargetCommit == null)
+                {
+                    continue;
+                }
+
+                var commitId = peeledTargetCommit.Id;
+
+                foreach (var potentialAncestorId in targetsSet)
                 {
-                    if (!targetsSet.Contains(commit))
+                    if (potentialAncestorId == commitId)
                     {
-                        continue;
+                        result.Add(reference);
+                        break;
                     }
 
-                    result.Add(reference);
-                    break;
+                    if (Proxy.git_graph_descendant_of(refsColl.repo.Handle, commitId, potentialAncestorId))
+                    {
+                        result.Add(reference);
+                        break;
+                    }
                 }
             }
 

Original file line number	Diff line number	Diff line change
`@@ -295,27 +295,40 @@ public static IEnumerable<Reference> ReachableFrom(`
`295`	`295`	`return Enumerable.Empty<Reference>();`
`296`	`296`	`}`
`297`	`297`
`298`		`- var targetsSet = new HashSet<Commit>(targets);`
	`298`	`+ List<ObjectId> targetsSet = targets.Select(c => c.Id).Distinct().ToList();`
`299`	`299`	`if (targetsSet.Count == 0)`
`300`	`300`	`{`
`301`	`301`	`return Enumerable.Empty<Reference>();`
`302`	`302`	`}`
`303`	`303`
`304`		`- var allCommits = refsColl.repo.Commits;`
`305`		`-`
`306`	`304`	`var result = new List<Reference>();`
`307`	`305`
`308`	`306`	`foreach (var reference in refs)`
`309`	`307`	`{`
`310`		`- foreach (var commit in allCommits.QueryBy(new CommitFilter { Since = reference }))`
	`308`	`+ var peeledTargetCommit = reference`
	`309`	`+ .ResolveToDirectReference()`
	`310`	`+ .Target.DereferenceToCommit(false);`
	`311`	`+`
	`312`	`+ if (peeledTargetCommit == null)`
	`313`	`+ {`
	`314`	`+ continue;`
	`315`	`+ }`
	`316`	`+`
	`317`	`+ var commitId = peeledTargetCommit.Id;`
	`318`	`+`
	`319`	`+ foreach (var potentialAncestorId in targetsSet)`
`311`	`320`	`{`
`312`		`- if (!targetsSet.Contains(commit))`
	`321`	`+ if (potentialAncestorId == commitId)`
`313`	`322`	`{`
`314`		`- continue;`
	`323`	`+ result.Add(reference);`
	`324`	`+ break;`
`315`	`325`	`}`
`316`	`326`
`317`		`- result.Add(reference);`
`318`		`- break;`
	`327`	`+ if (Proxy.git_graph_descendant_of(refsColl.repo.Handle, commitId, potentialAncestorId))`
	`328`	`+ {`
	`329`	`+ result.Add(reference);`
	`330`	`+ break;`
	`331`	`+ }`
`319`	`332`	`}`
`320`	`333`	`}`
`321`	`334`