feat(tag): add more bindings and api methods

lib/src/bindings/tag.dart

@@ -4,6 +4,26 @@ import '../error.dart';
 import 'libgit2_bindings.dart';
 import '../util.dart';
 
+/// Fill a list with all the tags in the repository.
+///
+/// Throws a [LibGit2Error] if error occured.
+List<String> list(Pointer<git_repository> repo) {
+  final out = calloc<git_strarray>();
+  final error = libgit2.git_tag_list(out, repo);
+
+  var result = <String>[];
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    for (var i = 0; i < out.ref.count; i++) {
+      result.add(out.ref.strings[i].cast<Utf8>().toDartString());
+    }
+    calloc.free(out);
+    return result;
+  }
+}
+
 /// Lookup a tag object from the repository.
 ///
 /// Throws a [LibGit2Error] if error occured.
@@ -99,5 +119,29 @@ Pointer<git_oid> create({
   }
 }
 
+/// Delete an existing tag reference.
+///
+/// The tag name will be checked for validity.
+///
+/// Throws a [LibGit2Error] if error occured.
+void delete({
+  required Pointer<git_repository> repoPointer,
+  required String tagName,
+}) {
+  final tagNameC = tagName.toNativeUtf8().cast<Int8>();
+  final error = libgit2.git_tag_delete(repoPointer, tagNameC);
+
+  calloc.free(tagNameC);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Get the repository that contains the tag.
+Pointer<git_repository> owner(Pointer<git_tag> tag) {
+  return libgit2.git_tag_owner(tag);
+}
+
 /// Close an open tag to release memory.
 void free(Pointer<git_tag> tag) => libgit2.git_tag_free(tag);

lib/src/tag.dart

@@ -74,6 +74,13 @@ class Tag {
     return Oid(result);
   }
 
+  /// Returns a list with all the tags in the repository.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  static List<String> list(Repository repo) {
+    return bindings.list(repo.pointer);
+  }
+
   /// Get the tagged object (commit, tree, blob, tag) of a tag.
   ///
   /// This method performs a repository lookup for the given object and returns it.
@@ -122,6 +129,16 @@ class Tag {
     }
   }
 
+  /// Deletes an existing tag reference.
+  ///
+  /// The tag name will be checked for validity.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  void delete() {
+    final owner = bindings.owner(_tagPointer);
+    bindings.delete(repoPointer: owner, tagName: name);
+  }
+
   /// Releases memory allocated for tag object.
   void free() => bindings.free(_tagPointer);
 }

test/tag_test.dart

@@ -80,5 +80,16 @@ void main() {
       newTagTarget.free();
       signature.free();
     });
+
+    test('returns list of tags in repository', () {
+      expect(Tag.list(repo), ['v0.1', 'v0.2']);
+    });
+
+    test('successfully deletes tag', () {
+      expect(Tag.list(repo), ['v0.1', 'v0.2']);
+
+      tag.delete();
+      expect(Tag.list(repo), ['v0.1']);
+    });
   });
 }