refactor: use libgit free() functions instead of calloc()

example/config_example.dart

@@ -9,8 +9,8 @@ void main() {
   for (final entry in entries.entries) {
     print('${entry.key}: ${entry.value}');
   }
-  // .close should be called on object to free memory when done.
-  config.close();
+  // free() should be called on object to free memory when done.
+  config.free();
 
   // Open config file at provided path.
   // Exception is thrown if file not found.
@@ -31,7 +31,7 @@ void main() {
     // Delete variable
     repoConfig.deleteEntry('core.variable');
 
-    repoConfig.close();
+    repoConfig.free();
   } catch (e) {
     print(e);
   }
@@ -45,7 +45,7 @@ void main() {
     final userName = globalConfig.getValue('user.name');
     print('\nUser Name from global config: $userName');
 
-    globalConfig.close();
+    globalConfig.free();
   } catch (e) {
     print('\n$e');
   }

example/reference_example.dart

@@ -11,5 +11,5 @@ void main() {
   print('Reference full name: ${ref.name}');
 
   ref.free();
-  repo.close();
+  repo.free();
 }

example/repository_example.dart

@@ -13,8 +13,8 @@ void main() {
     print('Is head detached: ${repo.isHeadDetached}');
     print('Repository refs: ${repo.references}');
 
-    // close() should be called on object to free memory when done.
-    repo.close();
+    // free() should be called on object to free memory when done.
+    repo.free();
   } catch (e) {
     print(e);
   }

lib/src/bindings/config.dart

@@ -284,3 +284,6 @@ void deleteMultivar(
   calloc.free(name);
   calloc.free(regexpC);
 }
+
+/// Free the configuration and its associated memory and files.
+void free(Pointer<git_config> cfg) => libgit2.git_config_free(cfg);

lib/src/bindings/reference.dart

@@ -215,3 +215,6 @@ bool isValidName(String name) {
   calloc.free(refname);
   return result == 1 ? true : false;
 }
+
+/// Free the given reference.
+void free(Pointer<git_reference> ref) => libgit2.git_reference_free(ref);

lib/src/bindings/repository.dart

@@ -446,3 +446,6 @@ Pointer<Pointer<git_object>> revParseSingle(
 
   return out;
 }
+
+/// Free a previously allocated repository.
+void free(Pointer<git_repository> repo) => libgit2.git_repository_free(repo);

lib/src/config.dart

@@ -17,7 +17,7 @@ class Config {
   /// [path] should point to single on-disk file; it's expected to be a native
   /// Git config file following the default Git config syntax (see man git-config).
   ///
-  /// [Config] object should be closed with [close] function to release allocated memory.
+  /// [Config] object should be closed with [free] function to release allocated memory.
   Config.open({this.path}) {
     libgit2.git_libgit2_init();
 
@@ -145,8 +145,8 @@ class Config {
   }
 
   /// Releases memory allocated for config object.
-  void close() {
-    calloc.free(_configPointer);
+  void free() {
+    bindings.free(_configPointer);
     libgit2.git_libgit2_shutdown();
   }
 }

lib/src/reference.dart

@@ -138,7 +138,7 @@ class Reference {
 
   /// Releases memory allocated for reference object.
   void free() {
-    calloc.free(_refPointer);
+    bindings.free(_refPointer);
     libgit2.git_libgit2_shutdown();
   }
 }

lib/src/repository.dart

@@ -14,7 +14,7 @@ class Repository {
   /// or to the working directory. For a bare repository, [path] should directly
   /// point to the repository folder.
   ///
-  /// [Repository] object should be close with [close] function to release allocated memory.
+  /// [Repository] object should be close with [free] function to release allocated memory.
   ///
   /// Throws a [LibGit2Error] if error occured.
   Repository.open(String path) {
@@ -237,8 +237,8 @@ class Repository {
   String get workdir => bindings.workdir(_repoPointer);
 
   /// Releases memory allocated for repository object.
-  void close() {
-    calloc.free(_repoPointer);
+  void free() {
+    bindings.free(_repoPointer);
     libgit2.git_libgit2_shutdown();
   }
 

test/config_test.dart

@@ -26,7 +26,7 @@ void main() {
     });
 
     tearDown(() {
-      config.close();
+      config.free();
       File('$tmpDir/$configFileName').deleteSync();
     });
 

test/odb_test.dart

@@ -26,7 +26,7 @@ void main() {
     });
 
     tearDownAll(() async {
-      repo.close();
+      repo.free();
       await Directory(tmpDir).delete(recursive: true);
     });
 

test/reference_test.dart

@@ -27,7 +27,7 @@ void main() {
     });
 
     tearDownAll(() async {
-      repo.close();
+      repo.free();
       await Directory(tmpDir).delete(recursive: true);
     });
 

test/reflog_test.dart

@@ -27,7 +27,7 @@ void main() {
     tearDownAll(() async {
       repo.head.free();
       reflog.free();
-      repo.close();
+      repo.free();
       await Directory(tmpDir).delete(recursive: true);
     });
 

test/repository_test.dart

@@ -22,7 +22,7 @@ void main() {
         });
 
         tearDown(() {
-          repo.close();
+          repo.free();
         });
 
         test('opens successfully', () {
@@ -67,7 +67,7 @@ void main() {
         });
 
         tearDown(() {
-          repo.close();
+          repo.free();
         });
 
         test('opens standart repository from working directory successfully',
@@ -144,7 +144,7 @@ void main() {
       });
 
       tearDownAll(() async {
-        repo.close();
+        repo.free();
         await Directory(tmpDir).delete(recursive: true);
       });