feat(repository): add api method for revparse_single

lib/src/bindings/object.dart

@@ -0,0 +1,6 @@
+import 'dart:ffi';
+import 'libgit2_bindings.dart';
+import '../util.dart';
+
+/// Get the object type of an object.
+int type(Pointer<git_object> obj) => libgit2.git_object_type(obj);

lib/src/bindings/repository.dart

@@ -511,6 +511,8 @@ Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
 }
 
 /// Find a single object, as specified by a [spec] string.
+/// See `man gitrevisions`, or https://git-scm.com/docs/git-rev-parse.html#_specifying_revisions
+/// for information on the syntax accepted.
 ///
 /// The returned object should be released when no longer needed.
 ///

lib/src/enums.dart

@@ -17,3 +17,5 @@ enum GitFilemode { undreadable, tree, blob, blobExecutable, link, commit }
 /// [reverse] Iterate through the repository contents in reverse
 /// order; this sorting mode can be combined with any of the above.
 enum GitSort { none, topological, time, reverse }
+
+enum GitObject { commit, tree, blob, tag }

lib/src/repository.dart

@@ -1,15 +1,14 @@
 import 'dart:ffi';
-import 'package:libgit2dart/src/enums.dart';
+import 'bindings/libgit2_bindings.dart';
-import 'package:libgit2dart/src/revwalk.dart';
+import 'bindings/repository.dart' as bindings;
-
 import 'commit.dart';
 import 'config.dart';
 import 'index.dart';
 import 'odb.dart';
 import 'oid.dart';
 import 'reference.dart';
-import 'bindings/libgit2_bindings.dart';
+import 'revwalk.dart';
-import 'bindings/repository.dart' as bindings;
+import 'enums.dart';
 import 'util.dart';
 
 class Repository {
@@ -324,6 +323,17 @@ class Repository {
     return Commit.lookup(this, oid);
   }
 
+  /// Find a single object, as specified by a [spec] string.
+  /// See `man gitrevisions`, or https://git-scm.com/docs/git-rev-parse.html#_specifying_revisions
+  /// for information on the syntax accepted.
+  ///
+  /// The returned object should be released when no longer needed.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  Commit revParseSingle(String spec) {
+    return Commit(bindings.revParseSingle(_repoPointer, spec).cast());
+  }
+
   /// Returns the list of commits starting from provided [oid].
   ///
   /// If [sorting] isn't provided default will be used (reverse chronological order, like in git).

test/repository_test.dart

@@ -199,6 +199,24 @@ void main() {
         }
       });
 
+      test('returns commit with different spec strings', () {
+        const headSHA = '78b8bf123e3952c970ae5c1ce0a3ea1d1336f6e8';
+        const parentSHA = 'c68ff54aabf660fcdd9a2838d401583fe31249e3';
+
+        final headCommit = repo.revParseSingle('HEAD');
+        expect(headCommit.id.sha, headSHA);
+
+        final parentCommit = repo.revParseSingle('HEAD^');
+        expect(parentCommit.id.sha, parentSHA);
+
+        final initCommit = repo.revParseSingle('@{-1}');
+        expect(initCommit.id.sha, '5aecfa0fb97eadaac050ccb99f03c3fb65460ad4');
+
+        headCommit.free();
+        parentCommit.free();
+        initCommit.free();
+      });
+
       group('.discover()', () {
         test('discovers repository', () async {
           final subDir = '${tmpDir}subdir1/subdir2/';