Use pointers for getting the list of advertised refs

Author: carlosmn

LibGit2Sharp/Core/GitOid.cs

@@ -2,6 +2,12 @@
 
 namespace LibGit2Sharp.Core
 {
+    internal struct git_oid
+    {
+        public const int Size = 20;
+        public unsafe fixed byte Id[20];
+    }
+
     /// <summary>
     /// Represents a unique id in git which is the sha1 hash of this id's content.
     /// </summary>

LibGit2Sharp/Core/GitRemoteHead.cs

@@ -4,12 +4,12 @@
 namespace LibGit2Sharp.Core
 {
     [StructLayout(LayoutKind.Sequential)]
-    internal struct GitRemoteHead
+    internal unsafe struct git_remote_head
     {
-        public bool Local;
-        public GitOid Oid;
-        public GitOid Loid;
-        public IntPtr NamePtr;
-        public IntPtr SymRefTargetPtr;
+        public int Local;
+        public git_oid Oid;
+        public git_oid Loid;
+        public char* Name;
+        public char* SymrefTarget;
     }
 }

LibGit2Sharp/Core/NativeMethods.cs

@@ -1244,10 +1244,8 @@ internal static extern int git_remote_lookup(
             RepositorySafeHandle repo,
             [MarshalAs(UnmanagedType.CustomMarshaler, MarshalCookie = UniqueId.UniqueIdentifier, MarshalTypeRef = typeof(StrictUtf8Marshaler))] string name);
 
-        internal delegate int git_headlist_cb(ref GitRemoteHead remoteHeadPtr, IntPtr payload);
-
         [DllImport(libgit2)]
-        internal static extern int git_remote_ls(out IntPtr heads, out UIntPtr size, RemoteSafeHandle remote);
+        internal static extern unsafe int git_remote_ls(out git_remote_head** heads, out UIntPtr size, RemoteSafeHandle remote);
 
         [DllImport(libgit2)]
         [return: MarshalAs(UnmanagedType.CustomMarshaler, MarshalCookie = UniqueId.UniqueIdentifier, MarshalTypeRef = typeof(LaxUtf8NoCleanupMarshaler))]

LibGit2Sharp/Core/Proxy.cs

@@ -2214,32 +2214,23 @@ public static IList<string> git_remote_list(RepositorySafeHandle repo)
             }
         }
 
-        public static IEnumerable<Reference> git_remote_ls(Repository repository, RemoteSafeHandle remote)
+        public static unsafe IEnumerable<Reference> git_remote_ls(Repository repository, RemoteSafeHandle remote)
         {
-            IntPtr heads;
+            git_remote_head** heads;
             UIntPtr count;
 
             int res = NativeMethods.git_remote_ls(out heads, out count, remote);
             Ensure.ZeroResult(res);
 
-            var intCount = (int)count.ToUInt32();
-
-            if (intCount < 0)
-            {
-                throw new OverflowException();
-            }
-
+            var intCount = checked(count.ToUInt32());
             var directRefs = new Dictionary<string, Reference>();
             var symRefs = new Dictionary<string, string>();
 
-            IntPtr currentHead = heads;
-
             for (int i = 0; i < intCount; i++)
             {
-                var remoteHead = Marshal.ReadIntPtr(currentHead).MarshalAs<GitRemoteHead>();
-
-                string name = LaxUtf8Marshaler.FromNative(remoteHead.NamePtr);
-                string symRefTarget = LaxUtf8Marshaler.FromNative(remoteHead.SymRefTargetPtr);
+                git_remote_head* currentHead = heads[i];
+                string name = LaxUtf8Marshaler.FromNative(currentHead->Name);
+                string symRefTarget = LaxUtf8Marshaler.FromNative(currentHead->SymrefTarget);
 
                 // The name pointer should never be null - if it is,
                 // this indicates a bug somewhere (libgit2, server, etc).
@@ -2254,10 +2245,8 @@ public static IEnumerable<Reference> git_remote_ls(Repository repository, Remote
                 }
                 else
                 {
-                    directRefs.Add(name, new DirectReference(name, repository, remoteHead.Oid));
+                    directRefs.Add(name, new DirectReference(name, repository, new ObjectId(currentHead->Oid.Id)));
                 }
-
-                currentHead = IntPtr.Add(currentHead, IntPtr.Size);
             }
 
             for (int i = 0; i < symRefs.Count; i++)

LibGit2Sharp/ObjectId.cs

@@ -57,6 +57,22 @@ public ObjectId(byte[] rawId)
             Ensure.ArgumentConformsTo(rawId, b => b.Length == rawSize, "rawId");
         }
 
+        internal unsafe ObjectId(byte* rawId)
+        {
+            byte[] id = new byte[GitOid.Size];
+
+            fixed(byte* p = id)
+            {
+                for (int i = 0; i < rawSize; i++)
+                {
+                    p[i] = rawId[i];
+                }
+            }
+
+            this.oid = new GitOid { Id = id };
+            this.sha = ToString(oid.Id, oid.Id.Length * 2);
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ObjectId"/> class.
         /// </summary>