feat(reference): add ability to create direct reference

lib/src/reference.dart

@@ -2,7 +2,6 @@ import 'dart:ffi';
 import 'package:ffi/ffi.dart';
 import 'bindings/libgit2_bindings.dart';
 import 'bindings/reference.dart' as bindings;
-import 'repository.dart';
 import 'oid.dart';
 import 'util.dart';
 
@@ -15,22 +14,45 @@ class Reference {
     libgit2.git_libgit2_init();
   }
 
+  /// Initializes a new instance of the [Reference] class by creating a new direct reference.
+  ///
+  /// The direct reference will be created in the repository and written to the disk.
+  /// The generated [Reference] object must be freed by the user.
+  ///
+  /// Valid reference names must follow one of two patterns:
+  ///
+  /// Top-level names must contain only capital letters and underscores, and must begin and end
+  /// with a letter. (e.g. "HEAD", "ORIG_HEAD").
+  /// Names prefixed with "refs/" can be almost anything. You must avoid the characters
+  /// '~', '^', ':', '\', '?', '[', and '*', and the sequences ".." and "@{" which have
+  /// special meaning to revparse.
+  ///
+  /// Throws a [LibGit2Error] if a reference already exists with the given name
+  /// unless force is true, in which case it will be overwritten.
+  ///
+  /// The message for the reflog will be ignored if the reference does not belong in the
+  /// standard set (HEAD, branches and remote-tracking branches) and it does not have a reflog.
+  Reference.createDirect({
+    required Pointer<git_repository> repo,
+    required String name,
+    required Pointer<git_oid> oid,
+    required bool force,
+    required String logMessage,
+  }) {
+    _refPointer = bindings.createDirect(repo, name, oid, force, logMessage);
+  }
+
   /// Initializes a new instance of the [Reference] class by
-  /// lookingup a reference by [name] in a [repository].
+  /// lookingup a reference by [name] in a repository.
   ///
   /// Should be freed with `free()` to release allocated memory.
   ///
   /// The name will be checked for validity.
   ///
   /// Throws a [LibGit2Error] if error occured.
-  Reference.lookup(Repository repository, String name) {
+  Reference.lookup(Pointer<git_repository> repo, String name) {
     libgit2.git_libgit2_init();
-
-    try {
-      _refPointer = bindings.lookup(repository.pointer, name);
-    } catch (e) {
-      rethrow;
-    }
+    _refPointer = bindings.lookup(repo, name);
   }
 
   /// Pointer to memory address for allocated reference object.
@@ -60,18 +82,18 @@ class Reference {
         : ReferenceType.symbolic;
   }
 
-  /// Returns the SHA hex of the OID pointed to by a reference.
-  String get target {
-    late final Pointer<git_oid>? oidPointer;
-    final sha = '';
+  /// Returns the OID pointed to by a reference.
+  ///
+  /// Throws an exception if error occured.
+  Oid get target {
+    late final Pointer<git_oid> oidPointer;
 
     if (type == ReferenceType.direct) {
       oidPointer = bindings.target(_refPointer);
     } else {
       oidPointer = bindings.target(bindings.resolve(_refPointer));
     }
-
-    return oidPointer == nullptr ? sha : Oid(oidPointer!).sha;
+    return Oid(oidPointer);
   }
 
   /// Returns the full name of a reference.
@@ -81,22 +103,14 @@ class Reference {
   ///
   /// Throws a [LibGit2Error] if error occured.
   static List<String> list(Pointer<git_repository> repo) {
-    try {
-      return bindings.list(repo);
-    } catch (e) {
-      rethrow;
-    }
+    return bindings.list(repo);
   }
 
   /// Checks if a reflog exists for the specified reference [name].
   ///
   /// Throws a [LibGit2Error] if error occured.
-  static bool hasLog(Repository repo, String name) {
-    try {
-      return bindings.hasLog(repo.pointer, name);
-    } catch (e) {
-      rethrow;
-    }
+  static bool hasLog(Pointer<git_repository> repo, String name) {
+    return bindings.hasLog(repo, name);
   }
 
   /// Checks if a reference is a local branch.
@@ -111,6 +125,17 @@ class Reference {
   /// Check if a reference is a tag.
   bool get isTag => bindings.isTag(_refPointer);
 
+  /// Returns the repository where a reference resides.
+  Pointer<git_repository> get owner => bindings.owner(_refPointer);
+
+  /// Delete an existing reference.
+  ///
+  /// This method works for both direct and symbolic references.
+  /// The reference will be immediately removed on disk but the memory will not be freed.
+  ///
+  /// Throws a [LibGit2Error] if the reference has changed from the time it was looked up.
+  void delete() => bindings.delete(_refPointer);
+
   /// Releases memory allocated for reference object.
   void free() {
     calloc.free(_refPointer);