feat(repository): add ability to lookup different types of git objects with []

lib/src/blob.dart

@@ -3,13 +3,23 @@ import 'bindings/libgit2_bindings.dart';
 import 'bindings/blob.dart' as bindings;
 import 'oid.dart';
 import 'repository.dart';
+import 'util.dart';
 
 class Blob {
-  /// Initializes a new instance of [Blob] class from provided
-  /// [Repository] and [Oid] objects.
+  /// Initializes a new instance of [Blob] class from provided pointer to
+  /// blob object in memory.
   ///
   /// Should be freed with `free()` to release allocated memory.
-  Blob.lookup(Repository repo, Oid oid) {
+  Blob(this._blobPointer) {
+    libgit2.git_libgit2_init();
+  }
+
+  /// Initializes a new instance of [Blob] class from provided
+  /// [Repository] object and [sha] hex string.
+  ///
+  /// Should be freed with `free()` to release allocated memory.
+  Blob.lookup(Repository repo, String sha) {
+    final oid = Oid.fromSHA(repo, sha);
     _blobPointer = bindings.lookup(repo.pointer, oid.pointer);
   }
 

lib/src/commit.dart

@@ -16,11 +16,12 @@ class Commit {
     libgit2.git_libgit2_init();
   }
 
-  /// Initializes a new instance of [Commit] class from provided [Repository]
-  /// and [Oid] objects.
+  /// Initializes a new instance of [Commit] class from provided [Repository] object
+  /// and [sha] hex string.
   ///
   /// Should be freed with `free()` to release allocated memory.
-  Commit.lookup(Repository repo, Oid oid) {
+  Commit.lookup(Repository repo, String sha) {
+    final oid = Oid.fromSHA(repo, sha);
     _commitPointer = bindings.lookup(repo.pointer, oid.pointer);
   }
 
@@ -40,8 +41,7 @@ class Commit {
     String? updateRef,
     String? messageEncoding,
   }) {
-    final treeOid = Oid.fromSHA(repo, treeSHA);
-    final tree = Tree.lookup(repo, treeOid);
+    final tree = Tree.lookup(repo, treeSHA);
 
     final result = Oid(bindings.create(
       repo.pointer,

lib/src/git_types.dart

@@ -63,33 +63,33 @@ class GitSort {
 }
 
 /// Basic type (loose or packed) of any Git object.
-class GitObjectType {
-  const GitObjectType._(this._value);
+class GitObject {
+  const GitObject._(this._value);
   final int _value;
 
   /// Object can be any of the following.
-  static const any = GitObjectType._(-2);
+  static const any = GitObject._(-2);
 
   /// Object is invalid.
-  static const invalid = GitObjectType._(-1);
+  static const invalid = GitObject._(-1);
 
   /// A commit object.
-  static const commit = GitObjectType._(1);
+  static const commit = GitObject._(1);
 
   /// A tree (directory listing) object.
-  static const tree = GitObjectType._(2);
+  static const tree = GitObject._(2);
 
   /// A file revision object.
-  static const blob = GitObjectType._(3);
+  static const blob = GitObject._(3);
 
   /// An annotated tag object.
-  static const tag = GitObjectType._(4);
+  static const tag = GitObject._(4);
 
   /// A delta, base is given by an offset.
-  static const offsetDelta = GitObjectType._(6);
+  static const offsetDelta = GitObject._(6);
 
   /// A delta, base is given by object id.
-  static const refDelta = GitObjectType._(7);
+  static const refDelta = GitObject._(7);
 
   int get value => _value;
 }

lib/src/index.dart

@@ -93,21 +93,21 @@ class Index {
   /// Updates the contents of an existing index object in memory by reading from the
   /// specified tree.
   void readTree(Object target) {
-    late final Oid oid;
     late final Tree tree;
+
     if (target is Oid) {
       final repo = Repository(bindings.owner(_indexPointer));
-      tree = Tree.lookup(repo, target);
+      tree = Tree.lookup(repo, target.sha);
     } else if (target is Tree) {
       tree = target;
-    } else if (isValidShaHex(target as String)) {
+    } else if (target is String) {
       final repo = Repository(bindings.owner(_indexPointer));
-      oid = Oid.fromSHA(repo, target);
-      tree = Tree.lookup(repo, oid);
+      tree = Tree.lookup(repo, target);
     } else {
       throw ArgumentError.value(
           '$target should be either Oid object, SHA hex string or Tree object');
     }
+
     bindings.readTree(_indexPointer, tree.pointer);
     tree.free();
   }

lib/src/oid.dart

@@ -15,14 +15,20 @@ class Oid {
   /// in the ODB of [repository] with provided hexadecimal [sha] string that is 40 characters
   /// long or shorter.
   ///
+  /// Throws [ArgumentError] if provided [sha] hex string is not valid.
+  ///
   /// Throws a [LibGit2Error] if error occured.
   Oid.fromSHA(Repository repository, String sha) {
-    if (sha.length == 40) {
-      _oidPointer = bindings.fromSHA(sha);
+    if (isValidShaHex(sha)) {
+      if (sha.length == 40) {
+        _oidPointer = bindings.fromSHA(sha);
+      } else {
+        final odb = repository.odb;
+        _oidPointer = odb.existsPrefix(bindings.fromStrN(sha), sha.length);
+        odb.free();
+      }
     } else {
-      final odb = repository.odb;
-      _oidPointer = odb.existsPrefix(bindings.fromStrN(sha), sha.length);
-      odb.free();
+      throw ArgumentError.value('$sha is not a valid sha hex string');
     }
   }
 

lib/src/repository.dart

@@ -4,6 +4,7 @@ import 'package:libgit2dart/libgit2dart.dart';
 import 'bindings/libgit2_bindings.dart';
 import 'bindings/repository.dart' as bindings;
 import 'bindings/merge.dart' as merge_bindings;
+import 'bindings/object.dart' as object_bindings;
 import 'commit.dart';
 import 'config.dart';
 import 'index.dart';
@@ -273,8 +274,8 @@ class Repository {
     late final Oid oid;
     late final bool isDirect;
 
-    if (target.runtimeType == Oid) {
-      oid = target as Oid;
+    if (target is Oid) {
+      oid = target;
       isDirect = true;
     } else if (isValidShaHex(target as String)) {
       oid = Oid.fromSHA(this, target);
@@ -314,18 +315,39 @@ class Repository {
   /// Throws a [LibGit2Error] if error occured.
   Odb get odb => Odb(bindings.odb(_repoPointer));
 
-  /// Looksup [Commit] for provided [sha] hex string.
+  /// Looksup git object (commit, tree, blob, tag) for provided [sha] hex string.
   ///
-  /// Throws [ArgumentError] if provided [sha] is not valid sha hex string.
-  Commit operator [](String sha) {
-    late final Oid oid;
+  /// Returned object should be explicitly downcasted to one of four of git object types.
+  ///
+  /// ```dart
+  /// final commit = repo['s0m3sh4'] as Commit;
+  /// final tree = repo['s0m3sh4'] as Tree;
+  /// final blob = repo['s0m3sh4'] as Blob;
+  /// final tag = repo['s0m3sh4'] as Tag;
+  /// ```
+  ///
+  /// Throws [ArgumentError] if provided [sha] is not pointing to commit, tree, blob or tag.
+  Object operator [](String sha) {
+    final oid = Oid.fromSHA(this, sha);
+    final object = object_bindings.lookup(
+      _repoPointer,
+      oid.pointer,
+      GitObject.any.value,
+    );
+    final type = object_bindings.type(object);
 
-    if (isValidShaHex(sha)) {
-      oid = Oid.fromSHA(this, sha);
+    if (type == GitObject.commit.value) {
+      return Commit(object.cast());
+    } else if (type == GitObject.tree.value) {
+      return Tree(object.cast());
+    } else if (type == GitObject.blob.value) {
+      return Blob(object.cast());
+    } else if (type == GitObject.tag.value) {
+      return Tag(object.cast());
     } else {
-      throw ArgumentError.value('$sha is not a valid sha hex string');
+      throw ArgumentError.value(
+          '$sha should be pointing to either commit, tree, blob or a tag');
     }
-    return Commit.lookup(this, oid);
   }
 
   /// Returns the list of commits starting from provided [oid].
@@ -415,7 +437,7 @@ class Repository {
   Oid createTag({
     required String tagName,
     required Oid target,
-    required GitObjectType targetType,
+    required GitObject targetType,
     required Signature tagger,
     required String message,
     bool force = false,

lib/src/tag.dart

@@ -8,13 +8,23 @@ import 'oid.dart';
 import 'repository.dart';
 import 'signature.dart';
 import 'git_types.dart';
+import 'util.dart';
 
 class Tag {
-  /// Initializes a new instance of [Tag] class from provided
-  /// [Repository] and [Oid] objects.
+  /// Initializes a new instance of [Tag] class from provided pointer to
+  /// tag object in memory.
   ///
   /// Should be freed with `free()` to release allocated memory.
-  Tag.lookup(Repository repo, Oid oid) {
+  Tag(this._tagPointer) {
+    libgit2.git_libgit2_init();
+  }
+
+  /// Initializes a new instance of [Tag] class from provided
+  /// [Repository] object and [sha] hex string.
+  ///
+  /// Should be freed with `free()` to release allocated memory.
+  Tag.lookup(Repository repo, String sha) {
+    final oid = Oid.fromSHA(repo, sha);
     _tagPointer = bindings.lookup(repo.pointer, oid.pointer);
   }
 
@@ -39,7 +49,7 @@ class Tag {
     required Repository repository,
     required String tagName,
     required Oid target,
-    required GitObjectType targetType,
+    required GitObject targetType,
     required Signature tagger,
     required String message,
     bool force = false,

lib/src/tree.dart

@@ -7,11 +7,20 @@ import 'git_types.dart';
 import 'util.dart';
 
 class Tree {
-  /// Initializes a new instance of [Tree] class from provided
-  /// [Repository] and [Oid] objects.
+  /// Initializes a new instance of [Tree] class from provided pointer to
+  /// tree object in memory.
   ///
   /// Should be freed with `free()` to release allocated memory.
-  Tree.lookup(Repository repo, Oid oid) {
+  Tree(this._treePointer) {
+    libgit2.git_libgit2_init();
+  }
+
+  /// Initializes a new instance of [Tree] class from provided
+  /// [Repository] object and [sha] hex string.
+  ///
+  /// Should be freed with `free()` to release allocated memory.
+  Tree.lookup(Repository repo, String sha) {
+    final oid = Oid.fromSHA(repo, sha);
     _treePointer = bindings.lookup(repo.pointer, oid.pointer);
   }