refactor: use ffi Arena for resource management

lib/libgit2dart.dart

@@ -1,5 +1,12 @@
 export 'src/repository.dart';
 export 'src/config.dart';
+export 'src/commit.dart';
+export 'src/index.dart';
+export 'src/odb.dart';
+export 'src/oid.dart';
+export 'src/reference.dart';
+export 'src/reflog.dart';
+export 'src/tree.dart';
 export 'src/signature.dart';
 export 'src/error.dart';
 export 'src/enums.dart';

lib/src/bindings/commit.dart

@@ -10,7 +10,8 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_commit> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
-  final out = calloc<Pointer<git_commit>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_commit>>();
     final error = libgit2.git_commit_lookup(out, repo, id);
 
     if (error < 0) {
@@ -18,6 +19,7 @@ Pointer<git_commit> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the encoding for the message of a commit, as a string representing a standard encoding name.
@@ -26,6 +28,7 @@ Pointer<git_commit> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
 /// in that case UTF-8 is assumed.
 String messageEncoding(Pointer<git_commit> commit) {
   final result = libgit2.git_commit_message_encoding(commit);
+
   if (result == nullptr) {
     return 'utf-8';
   } else {

lib/src/bindings/config.dart

@@ -11,7 +11,8 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> newConfig() {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_config>>();
     final error = libgit2.git_config_new(out);
 
     if (error < 0) {
@@ -19,22 +20,24 @@ Pointer<git_config> newConfig() {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Create a new config instance containing a single on-disk file
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> open(String path) {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_config>>();
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_config_open_ondisk(out, pathC);
-  calloc.free(pathC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Open the global, XDG and system configuration files
@@ -45,7 +48,8 @@ Pointer<git_config> open(String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> openDefault() {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_config>>();
     final error = libgit2.git_config_open_default(out);
 
     if (error < 0) {
@@ -53,6 +57,7 @@ Pointer<git_config> openDefault() {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Locate the path to the global configuration file
@@ -69,16 +74,17 @@ Pointer<git_config> openDefault() {
 ///
 /// Throws an error if file has not been found.
 String findGlobal() {
-  final out = calloc<git_buf>(sizeOf<git_buf>());
+  return using((Arena arena) {
+    final out = arena<git_buf>(sizeOf<git_buf>());
     final error = libgit2.git_config_find_global(out);
     final path = out.ref.ptr.cast<Utf8>().toDartString();
-  calloc.free(out);
 
     if (error != 0) {
       throw Error();
     } else {
       return path;
     }
+  });
 }
 
 /// Locate the path to the system configuration file
@@ -87,16 +93,17 @@ String findGlobal() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String findSystem() {
-  final out = calloc<git_buf>();
+  return using((Arena arena) {
+    final out = arena<git_buf>();
     final error = libgit2.git_config_find_system(out);
     final path = out.ref.ptr.cast<Utf8>().toDartString();
-  calloc.free(out);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return path;
     }
+  });
 }
 
 /// Locate the path to the global xdg compatible configuration file
@@ -106,16 +113,17 @@ String findSystem() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String findXdg() {
-  final out = calloc<git_buf>();
+  return using((Arena arena) {
+    final out = arena<git_buf>();
     final error = libgit2.git_config_find_xdg(out);
     final path = out.ref.ptr.cast<Utf8>().toDartString();
-  calloc.free(out);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return path;
     }
+  });
 }
 
 /// Create a snapshot of the configuration.
@@ -126,7 +134,8 @@ String findXdg() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> snapshot(Pointer<git_config> config) {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_config>>();
     final error = libgit2.git_config_snapshot(out, config);
 
     if (error < 0) {
@@ -134,24 +143,24 @@ Pointer<git_config> snapshot(Pointer<git_config> config) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the value of a config variable.
 ///
 /// Throws a [LibGit2Error] if error occured.
 String getValue(Pointer<git_config> cfg, String variable) {
-  final out = calloc<Pointer<git_config_entry>>();
+  return using((Arena arena) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_config_entry>>();
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_config_get_entry(out, cfg, name);
-  final value = out.value;
-  calloc.free(out);
-  calloc.free(name);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
-    return value.ref.value.cast<Utf8>().toDartString();
+      return out.value.ref.value.cast<Utf8>().toDartString();
     }
+  });
 }
 
 /// Set the value of a boolean config variable in the config file with the
@@ -159,14 +168,15 @@ String getValue(Pointer<git_config> cfg, String variable) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setBool(Pointer<git_config> cfg, String variable, bool value) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
     final valueC = value ? 1 : 0;
     final error = libgit2.git_config_set_bool(cfg, name, valueC);
-  calloc.free(name);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Set the value of an integer config variable in the config file with the
@@ -174,13 +184,14 @@ void setBool(Pointer<git_config> cfg, String variable, bool value) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setInt(Pointer<git_config> cfg, String variable, int value) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_config_set_int64(cfg, name, value);
-  calloc.free(name);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Set the value of a string config variable in the config file with the
@@ -188,21 +199,22 @@ void setInt(Pointer<git_config> cfg, String variable, int value) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setString(Pointer<git_config> cfg, String variable, String value) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
-  final valueC = value.toNativeUtf8().cast<Int8>();
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
+    final valueC = value.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_config_set_string(cfg, name, valueC);
-  calloc.free(name);
-  calloc.free(valueC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Iterate over all the config variables.
 Map<String, String> getEntries(Pointer<git_config> cfg) {
-  final iterator = calloc<Pointer<git_config_iterator>>();
+  return using((Arena arena) {
-  final entry = calloc<Pointer<git_config_entry>>();
+    final iterator = arena<Pointer<git_config_iterator>>();
+    final entry = arena<Pointer<git_config_entry>>();
     libgit2.git_config_iterator_new(iterator, cfg);
     var error = 0;
     final entries = <String, String>{};
@@ -212,10 +224,9 @@ Map<String, String> getEntries(Pointer<git_config> cfg) {
       entries[entry.value.ref.name.cast<Utf8>().toDartString()] =
           entry.value.ref.value.cast<Utf8>().toDartString();
     }
-  calloc.free(entry);
-  calloc.free(iterator);
 
     return entries;
+  });
 }
 
 /// Delete a config variable from the config file with the highest level
@@ -223,13 +234,14 @@ Map<String, String> getEntries(Pointer<git_config> cfg) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void delete(Pointer<git_config> cfg, String variable) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_config_delete_entry(cfg, name);
-  calloc.free(name);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Iterate over the values of a multivar
@@ -241,10 +253,12 @@ List<String> multivarValues(
   String variable,
   String? regexp,
 ) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  return using((Arena arena) {
-  final regexpC = regexp?.toNativeUtf8().cast<Int8>() ?? nullptr;
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
-  final iterator = calloc<Pointer<git_config_iterator>>();
+    final regexpC =
-  final entry = calloc<Pointer<git_config_entry>>();
+        regexp?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
+    final iterator = arena<Pointer<git_config_iterator>>();
+    final entry = arena<Pointer<git_config_entry>>();
     libgit2.git_config_multivar_iterator_new(iterator, cfg, name, regexpC);
     var error = 0;
     final entries = <String>[];
@@ -258,12 +272,8 @@ List<String> multivarValues(
       }
     }
 
-  calloc.free(name);
-  calloc.free(regexpC);
-  calloc.free(iterator);
-  calloc.free(entry);
-
     return entries;
+  });
 }
 
 /// Set the value of a multivar config variable in the config file with the
@@ -276,14 +286,12 @@ void setMultivar(
   String regexp,
   String value,
 ) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
-  final regexpC = regexp.toNativeUtf8().cast<Int8>();
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
-  final valueC = value.toNativeUtf8().cast<Int8>();
+    final regexpC = regexp.toNativeUtf8(allocator: arena).cast<Int8>();
+    final valueC = value.toNativeUtf8(allocator: arena).cast<Int8>();
     libgit2.git_config_set_multivar(cfg, name, regexpC, valueC);
-
+  });
-  calloc.free(name);
-  calloc.free(regexpC);
-  calloc.free(valueC);
 }
 
 /// Deletes one or several values from a multivar in the config file
@@ -295,12 +303,11 @@ void deleteMultivar(
   String variable,
   String regexp,
 ) {
-  final name = variable.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
-  final regexpC = regexp.toNativeUtf8().cast<Int8>();
+    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
+    final regexpC = regexp.toNativeUtf8(allocator: arena).cast<Int8>();
     libgit2.git_config_delete_multivar(cfg, name, regexpC);
-
+  });
-  calloc.free(name);
-  calloc.free(regexpC);
 }
 
 /// Free the configuration and its associated memory and files.

lib/src/bindings/index.dart

@@ -62,11 +62,12 @@ Pointer<git_oid> writeTree(Pointer<git_index> index) {
 
 /// Find the first position of any entries which point to given path in the Git index.
 bool find(Pointer<git_index> index, String path) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+  return using((Arena arena) {
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final result = libgit2.git_index_find(nullptr, index, pathC);
-  calloc.free(pathC);
 
     return result == git_error_code.GIT_ENOTFOUND ? false : true;
+  });
 }
 
 /// Get the count of entries currently in the index.
@@ -97,15 +98,16 @@ Pointer<git_index_entry> getByPath(
   String path,
   int stage,
 ) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+  return using((Arena arena) {
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final result = libgit2.git_index_get_bypath(index, pathC, stage);
-  calloc.free(pathC);
 
     if (result == nullptr) {
       throw ArgumentError.value('$path was not found');
     } else {
       return result;
     }
+  });
 }
 
 /// Clear the contents (all the entries) of an index object.
@@ -150,13 +152,14 @@ void add(Pointer<git_index> index, Pointer<git_index_entry> sourceEntry) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void addByPath(Pointer<git_index> index, String path) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_index_add_bypath(index, pathC);
-  calloc.free(pathC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Add or update index entries matching files in the working directory.
@@ -169,10 +172,12 @@ void addByPath(Pointer<git_index> index, String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void addAll(Pointer<git_index> index, List<String> pathspec) {
-  var pathspecC = calloc<git_strarray>();
+  using((Arena arena) {
-  final List<Pointer<Int8>> pathPointers =
+    var pathspecC = arena<git_strarray>();
-      pathspec.map((e) => e.toNativeUtf8().cast<Int8>()).toList();
+    final List<Pointer<Int8>> pathPointers = pathspec
-  final Pointer<Pointer<Int8>> strArray = calloc(pathspec.length);
+        .map((e) => e.toNativeUtf8(allocator: arena).cast<Int8>())
+        .toList();
+    final Pointer<Pointer<Int8>> strArray = arena(pathspec.length);
 
     for (var i = 0; i < pathspec.length; i++) {
       strArray[i] = pathPointers[i];
@@ -189,15 +194,10 @@ void addAll(Pointer<git_index> index, List<String> pathspec) {
       nullptr,
     );
 
-  calloc.free(pathspecC);
-  calloc.free(strArray);
-  for (var p in pathPointers) {
-    calloc.free(p);
-  }
-
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Write an existing index object from memory back to disk using an atomic file lock.
@@ -215,23 +215,26 @@ void write(Pointer<git_index> index) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void remove(Pointer<git_index> index, String path, int stage) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_index_remove(index, pathC, stage);
-  calloc.free(pathC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Remove all matching index entries.
 ///
 /// Throws a [LibGit2Error] if error occured.
 void removeAll(Pointer<git_index> index, List<String> pathspec) {
-  final pathspecC = calloc<git_strarray>();
+  using((Arena arena) {
-  final List<Pointer<Int8>> pathPointers =
+    final pathspecC = arena<git_strarray>();
-      pathspec.map((e) => e.toNativeUtf8().cast<Int8>()).toList();
+    final List<Pointer<Int8>> pathPointers = pathspec
-  final Pointer<Pointer<Int8>> strArray = calloc(pathspec.length);
+        .map((e) => e.toNativeUtf8(allocator: arena).cast<Int8>())
+        .toList();
+    final Pointer<Pointer<Int8>> strArray = arena(pathspec.length);
 
     for (var i = 0; i < pathspec.length; i++) {
       strArray[i] = pathPointers[i];
@@ -247,15 +250,10 @@ void removeAll(Pointer<git_index> index, List<String> pathspec) {
       nullptr,
     );
 
-  calloc.free(pathspecC);
-  calloc.free(strArray);
-  for (var p in pathPointers) {
-    calloc.free(p);
-  }
-
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Get the repository this index relates to.

lib/src/bindings/oid.dart

@@ -42,16 +42,17 @@ Pointer<git_oid> fromSHA(String hex) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String toSHA(Pointer<git_oid> id) {
-  final out = calloc.allocate<Int8>(40);
+  return using((Arena arena) {
+    final out = arena<Int8>(40);
     final error = libgit2.git_oid_fmt(out, id);
     final result = out.cast<Utf8>().toDartString(length: 40);
-  malloc.free(out);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return result;
     }
+  });
 }
 
 /// Compare two oid structures.

lib/src/bindings/reference.dart

@@ -35,7 +35,8 @@ Pointer<git_oid> target(Pointer<git_reference> ref) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> resolve(Pointer<git_reference> ref) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_reference>>();
     final error = libgit2.git_reference_resolve(out, ref);
 
     if (error < 0) {
@@ -43,6 +44,7 @@ Pointer<git_reference> resolve(Pointer<git_reference> ref) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Lookup a reference by name in a repository.
@@ -53,16 +55,17 @@ Pointer<git_reference> resolve(Pointer<git_reference> ref) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> lookup(Pointer<git_repository> repo, String name) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_reference_lookup(out, repo, nameC);
-  calloc.free(nameC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Lookup a reference by DWIMing its short name.
@@ -72,24 +75,27 @@ Pointer<git_reference> lookup(Pointer<git_repository> repo, String name) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> lookupDWIM(Pointer<git_repository> repo, String name) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_reference_dwim(out, repo, nameC);
-  calloc.free(nameC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the full name of a reference.
 String name(Pointer<git_reference> ref) {
-  var result = calloc<Int8>();
+  return using((Arena arena) {
+    var result = arena<Int8>();
     result = libgit2.git_reference_name(ref);
 
     return result.cast<Utf8>().toDartString();
+  });
 }
 
 /// Get the reference's short name.
@@ -120,8 +126,9 @@ Pointer<git_reference> rename(
   bool force,
   String? logMessage,
 ) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final newNameC = newName.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
+    final newNameC = newName.toNativeUtf8(allocator: arena).cast<Int8>();
     final forceC = force == true ? 1 : 0;
     final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
     final error = libgit2.git_reference_rename(
@@ -131,14 +138,13 @@ Pointer<git_reference> rename(
       forceC,
       logMessageC,
     );
-  calloc.free(newNameC);
-  calloc.free(logMessageC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Fill a list with all the references that can be found in a repository.
@@ -148,7 +154,8 @@ Pointer<git_reference> rename(
 ///
 /// Throws a [LibGit2Error] if error occured.
 List<String> list(Pointer<git_repository> repo) {
-  var array = calloc<git_strarray>();
+  return using((Arena arena) {
+    var array = arena<git_strarray>();
     final error = libgit2.git_reference_list(array, repo);
     var result = <String>[];
 
@@ -161,23 +168,24 @@ List<String> list(Pointer<git_repository> repo) {
       }
     }
 
-  calloc.free(array);
     return result;
+  });
 }
 
 /// Check if a reflog exists for the specified reference.
 ///
 /// Throws a [LibGit2Error] if error occured.
 bool hasLog(Pointer<git_repository> repo, String name) {
-  final refname = name.toNativeUtf8().cast<Int8>();
+  return using((Arena arena) {
+    final refname = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_reference_has_log(repo, refname);
-  calloc.free(refname);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return error == 1 ? true : false;
     }
+  });
 }
 
 /// Check if a reference is a local branch.
@@ -233,8 +241,9 @@ Pointer<git_reference> createDirect(
   bool force,
   String? logMessage,
 ) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final forceC = force == true ? 1 : 0;
     final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
     final error = libgit2.git_reference_create(
@@ -245,14 +254,13 @@ Pointer<git_reference> createDirect(
       forceC,
       logMessageC,
     );
-  calloc.free(nameC);
-  calloc.free(logMessageC);
 
     if (error < 0) {
       throw (LibGit2Error(libgit2.git_error_last()));
     } else {
       return out.value;
     }
+  });
 }
 
 /// Create a new symbolic reference.
@@ -284,8 +292,9 @@ Pointer<git_reference> createSymbolic(
   bool force,
   String? logMessage,
 ) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final targetC = target.toNativeUtf8().cast<Int8>();
     final forceC = force == true ? 1 : 0;
     final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
@@ -297,15 +306,13 @@ Pointer<git_reference> createSymbolic(
       forceC,
       logMessageC,
     );
-  calloc.free(nameC);
-  calloc.free(targetC);
-  calloc.free(logMessageC);
 
     if (error < 0) {
       throw (LibGit2Error(libgit2.git_error_last()));
     } else {
       return out.value;
     }
+  });
 }
 
 /// Delete an existing reference.
@@ -338,16 +345,18 @@ Pointer<git_reference> setTarget(
   Pointer<git_oid> oid,
   String? logMessage,
 ) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
+    final out = arena<Pointer<git_reference>>();
+    final logMessageC =
+        logMessage?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
     final error = libgit2.git_reference_set_target(out, ref, oid, logMessageC);
-  calloc.free(logMessageC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Create a new reference with the same name as the given reference but a different
@@ -366,19 +375,20 @@ Pointer<git_reference> setTargetSymbolic(
   String target,
   String? logMessage,
 ) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
-  final targetC = target.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reference>>();
-  final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
+    final targetC = target.toNativeUtf8(allocator: arena).cast<Int8>();
-  final error =
+    final logMessageC =
-      libgit2.git_reference_symbolic_set_target(out, ref, targetC, logMessageC);
+        logMessage?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
-  calloc.free(targetC);
+    final error = libgit2.git_reference_symbolic_set_target(
-  calloc.free(logMessageC);
+        out, ref, targetC, logMessageC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Compare two references.
@@ -397,10 +407,12 @@ bool compare(Pointer<git_reference> ref1, Pointer<git_reference> ref2) {
 /// the characters '~', '^', ':', '\', '?', '[', and '*', and the sequences ".."
 /// and "@{" which have special meaning to revparse.
 bool isValidName(String name) {
-  final refname = name.toNativeUtf8().cast<Int8>();
+  return using((Arena arena) {
+    final refname = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final result = libgit2.git_reference_is_valid_name(refname);
-  calloc.free(refname);
+
     return result == 1 ? true : false;
+  });
 }
 
 /// Free the given reference.

lib/src/bindings/reflog.dart

@@ -13,16 +13,17 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reflog> read(Pointer<git_repository> repo, String name) {
-  final out = calloc<Pointer<git_reflog>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_reflog>>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_reflog_read(out, repo, nameC);
-  calloc.free(nameC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the number of log entries in a reflog.

lib/src/bindings/repository.dart

@@ -10,16 +10,17 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> open(String path) {
-  final out = calloc<Pointer<git_repository>>();
+  return using((Arena arena) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_repository>>();
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_repository_open(out, pathC);
-  calloc.free(pathC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
-  }
+    } else {
-
       return out.value;
+    }
+  });
 }
 
 /// Attempt to open an already-existing bare repository at [bare_path].
@@ -28,16 +29,17 @@ Pointer<git_repository> open(String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> openBare(String barePath) {
-  final out = calloc<Pointer<git_repository>>();
+  return using((Arena arena) {
-  final barePathC = barePath.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_repository>>();
+    final barePathC = barePath.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_repository_open_bare(out, barePathC);
-  calloc.free(barePathC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
-  }
+    } else {
-
       return out.value;
+    }
+  });
 }
 
 /// Look for a git repository and return its path. The lookup start from [startPath]
@@ -48,41 +50,40 @@ Pointer<git_repository> openBare(String barePath) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String discover(String startPath, String ceilingDirs) {
-  final out = calloc<git_buf>(sizeOf<git_buf>());
+  return using((Arena arena) {
-  final startPathC = startPath.toNativeUtf8().cast<Int8>();
+    final out = arena<git_buf>(sizeOf<git_buf>());
-  final ceilingDirsC = ceilingDirs.toNativeUtf8().cast<Int8>();
+    final startPathC = startPath.toNativeUtf8(allocator: arena).cast<Int8>();
+    final ceilingDirsC =
+        ceilingDirs.toNativeUtf8(allocator: arena).cast<Int8>();
     final error =
         libgit2.git_repository_discover(out, startPathC, 0, ceilingDirsC);
-  var result = '';
 
     if (error == git_error_code.GIT_ENOTFOUND) {
-    return result;
+      return '';
     } else if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
+    } else {
+      return out.ref.ptr.cast<Utf8>().toDartString();
     }
-
+  });
-  result = out.ref.ptr.cast<Utf8>().toDartString();
-  calloc.free(out);
-  calloc.free(startPathC);
-  calloc.free(ceilingDirsC);
-
-  return result;
 }
 
 /// Creates a new Git repository in the given folder.
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> init(String path, bool isBare) {
-  final out = calloc<Pointer<git_repository>>();
+  return using((Arena arena) {
-  final pathC = path.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_repository>>();
+    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final isBareC = isBare ? 1 : 0;
     final error = libgit2.git_repository_init(out, pathC, isBareC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
-  }
+    } else {
-
       return out.value;
+    }
+  });
 }
 
 /// Returns the path to the `.git` folder for normal repositories or the
@@ -124,13 +125,15 @@ String getNamespace(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setNamespace(Pointer<git_repository> repo, String? namespace) {
-  final nmspace = namespace?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  using((Arena arena) {
+    final nmspace =
+        namespace?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
     final error = libgit2.git_repository_set_namespace(repo, nmspace);
-  calloc.free(nmspace);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Check if a repository is bare or not.
@@ -162,7 +165,8 @@ bool isEmpty(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> head(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_reference>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_reference>>();
     final error = libgit2.git_repository_head(out, repo);
 
     if (error < 0) {
@@ -170,6 +174,7 @@ Pointer<git_reference> head(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Check if a repository's HEAD is detached.
@@ -208,19 +213,20 @@ bool isBranchUnborn(Pointer<git_repository> repo) {
 /// If both are set, this name and email will be used to write to the reflog.
 /// Pass NULL to unset. When unset, the identity will be taken from the repository's configuration.
 void setIdentity(Pointer<git_repository> repo, String? name, String? email) {
-  final nameC = name?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  using((Arena arena) {
-  final emailC = email?.toNativeUtf8().cast<Int8>() ?? nullptr;
+    final nameC = name?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
+    final emailC =
+        email?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
 
     libgit2.git_repository_set_ident(repo, nameC, emailC);
-
+  });
-  calloc.free(nameC);
-  calloc.free(emailC);
 }
 
 /// Retrieve the configured identity to use for reflogs.
 Map<String, String> identity(Pointer<git_repository> repo) {
-  final name = calloc<Pointer<Int8>>();
+  return using((Arena arena) {
-  final email = calloc<Pointer<Int8>>();
+    final name = arena<Pointer<Int8>>();
+    final email = arena<Pointer<Int8>>();
     libgit2.git_repository_ident(name, email, repo);
     var identity = <String, String>{};
 
@@ -231,10 +237,8 @@ Map<String, String> identity(Pointer<git_repository> repo) {
           email.value.cast<Utf8>().toDartString();
     }
 
-  calloc.free(name);
-  calloc.free(email);
-
     return identity;
+  });
 }
 
 /// Get the configuration file for this repository.
@@ -246,7 +250,8 @@ Map<String, String> identity(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> config(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_config>>();
     final error = libgit2.git_repository_config(out, repo);
 
     if (error < 0) {
@@ -254,6 +259,7 @@ Pointer<git_config> config(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get a snapshot of the repository's configuration.
@@ -265,7 +271,8 @@ Pointer<git_config> config(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_config>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_config>>();
     final error = libgit2.git_repository_config_snapshot(out, repo);
 
     if (error < 0) {
@@ -273,6 +280,7 @@ Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the Index file for this repository.
@@ -284,7 +292,8 @@ Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_index> index(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_index>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_index>>();
     final error = libgit2.git_repository_index(out, repo);
 
     if (error < 0) {
@@ -292,6 +301,7 @@ Pointer<git_index> index(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Determine if the repository was a shallow clone.
@@ -318,16 +328,16 @@ bool isWorktree(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String message(Pointer<git_repository> repo) {
-  final out = calloc<git_buf>();
+  return using((Arena arena) {
+    final out = arena<git_buf>(sizeOf<git_buf>());
     final error = libgit2.git_repository_message(out, repo);
-  final result = out.ref.ptr.cast<Utf8>().toDartString();
-  calloc.free(out);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
-    return result;
+      return out.ref.ptr.cast<Utf8>().toDartString();
     }
+  });
 }
 
 /// Remove git's prepared message.
@@ -344,7 +354,8 @@ void removeMessage(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_odb> odb(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_odb>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_odb>>();
     final error = libgit2.git_repository_odb(out, repo);
 
     if (error < 0) {
@@ -352,6 +363,7 @@ Pointer<git_odb> odb(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Get the Reference Database Backend for this repository.
@@ -364,7 +376,8 @@ Pointer<git_odb> odb(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
-  final out = calloc<Pointer<git_refdb>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_refdb>>();
     final error = libgit2.git_repository_refdb(out, repo);
 
     if (error < 0) {
@@ -372,6 +385,7 @@ Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Make the repository HEAD point to the specified reference.
@@ -387,13 +401,14 @@ Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setHead(Pointer<git_repository> repo, String ref) {
-  final refname = ref.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final refname = ref.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_repository_set_head(repo, refname);
-  calloc.free(refname);
 
-  if (error < 0 && error != -1) {
+    if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Make the repository HEAD directly point to the commit.
@@ -408,7 +423,7 @@ void setHead(Pointer<git_repository> repo, String ref) {
 void setHeadDetached(Pointer<git_repository> repo, Pointer<git_oid> commitish) {
   final error = libgit2.git_repository_set_head_detached(repo, commitish);
 
-  if (error < 0 && (error != -1 || error != -3)) {
+  if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   }
 }
@@ -427,7 +442,7 @@ void setHeadDetachedFromAnnotated(
   final error =
       libgit2.git_repository_set_head_detached_from_annotated(repo, commitish);
 
-  if (error < 0 && (error != -1 || error != -3)) {
+  if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   }
 }
@@ -447,15 +462,16 @@ void setWorkdir(
   String path,
   bool updateGitlink,
 ) {
-  final workdir = path.toNativeUtf8().cast<Int8>();
+  using((Arena arena) {
+    final workdir = path.toNativeUtf8(allocator: arena).cast<Int8>();
     final updateGitlinkC = updateGitlink ? 1 : 0;
     final error =
         libgit2.git_repository_set_workdir(repo, workdir, updateGitlinkC);
-  calloc.free(workdir);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     }
+  });
 }
 
 /// Determines the status of a git repository - ie, whether an operation
@@ -495,7 +511,8 @@ String workdir(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
-  final out = calloc<Pointer<git_repository>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_repository>>();
     final error = libgit2.git_repository_wrap_odb(out, odb);
 
     if (error < 0) {
@@ -503,6 +520,7 @@ Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Find a single object, as specified by a [spec] string.
@@ -510,24 +528,25 @@ Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
 /// The returned object should be released when no longer needed.
 ///
 /// Throws a [LibGit2Error] if error occured.
-Pointer<Pointer<git_object>> revParseSingle(
+Pointer<git_object> revParseSingle(
   Pointer<git_repository> repo,
   String spec,
 ) {
-  final out = calloc<Pointer<git_object>>();
+  return using((Arena arena) {
-  final specC = spec.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_object>>();
+    final specC = spec.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_revparse_single(
       out,
       repo,
       specC,
     );
-  calloc.free(specC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
+    } else {
+      return out.value;
     }
-
+  });
-  return out;
 }
 
 /// Free a previously allocated repository.

lib/src/bindings/signature.dart

@@ -16,36 +16,36 @@ Pointer<git_signature> create(
   int time,
   int offset,
 ) {
-  final out = calloc<Pointer<git_signature>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_signature>>();
-  final emailC = email.toNativeUtf8().cast<Int8>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
+    final emailC = email.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_signature_new(out, nameC, emailC, time, offset);
-  calloc.free(nameC);
-  calloc.free(emailC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Create a new action signature with a timestamp of 'now'.
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_signature> now(String name, String email) {
-  final out = calloc<Pointer<git_signature>>();
+  return using((Arena arena) {
-  final nameC = name.toNativeUtf8().cast<Int8>();
+    final out = arena<Pointer<git_signature>>();
-  final emailC = email.toNativeUtf8().cast<Int8>();
+    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
+    final emailC = email.toNativeUtf8(allocator: arena).cast<Int8>();
     final error = libgit2.git_signature_now(out, nameC, emailC);
-  calloc.free(nameC);
-  calloc.free(emailC);
 
     if (error < 0) {
       throw LibGit2Error(libgit2.git_error_last());
     } else {
       return out.value;
     }
+  });
 }
 
 /// Free an existing signature.

lib/src/bindings/tree.dart

@@ -11,7 +11,8 @@ Pointer<git_oid> id(Pointer<git_tree> tree) => libgit2.git_tree_id(tree);
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_tree> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
-  final out = calloc<Pointer<git_tree>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_tree>>();
     final error = libgit2.git_tree_lookup(out, repo, id);
 
     if (error < 0) {
@@ -19,6 +20,7 @@ Pointer<git_tree> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
     } else {
       return out.value;
     }
+  });
 }
 
 /// Lookup a tree object from the repository, given a prefix of its identifier (short id).
@@ -29,7 +31,8 @@ Pointer<git_tree> lookupPrefix(
   Pointer<git_oid> id,
   int len,
 ) {
-  final out = calloc<Pointer<git_tree>>();
+  return using((Arena arena) {
+    final out = arena<Pointer<git_tree>>();
     final error = libgit2.git_tree_lookup_prefix(out, repo, id, len);
 
     if (error < 0) {
@@ -37,6 +40,7 @@ Pointer<git_tree> lookupPrefix(
     } else {
       return out.value;
     }
+  });
 }
 
 /// Close an open tree.

test/commit_test.dart

@@ -2,7 +2,6 @@ import 'dart:io';
 
 import 'package:test/test.dart';
 import 'package:libgit2dart/libgit2dart.dart';
-import 'package:libgit2dart/src/commit.dart';
 import 'helpers/util.dart';
 
 void main() {

test/config_test.dart

@@ -1,8 +1,7 @@
 import 'dart:io';
 
 import 'package:test/test.dart';
-import 'package:libgit2dart/src/config.dart';
+import 'package:libgit2dart/libgit2dart.dart';
-import 'package:libgit2dart/src/error.dart';
 
 void main() {
   final tmpDir = Directory.systemTemp.path;

test/index_test.dart

@@ -1,9 +1,7 @@
 import 'dart:io';
 
-import 'package:libgit2dart/libgit2dart.dart';
 import 'package:test/test.dart';
-import 'package:libgit2dart/src/index.dart';
+import 'package:libgit2dart/libgit2dart.dart';
-
 import 'helpers/util.dart';
 
 void main() {

test/odb_test.dart

@@ -1,10 +1,7 @@
 import 'dart:io';
 
 import 'package:test/test.dart';
-import 'package:libgit2dart/src/repository.dart';
+import 'package:libgit2dart/libgit2dart.dart';
-import 'package:libgit2dart/src/odb.dart';
-import 'package:libgit2dart/src/oid.dart';
-
 import 'helpers/util.dart';
 
 void main() {

test/oid_test.dart

@@ -1,5 +1,5 @@
 import 'package:test/test.dart';
-import 'package:libgit2dart/src/oid.dart';
+import 'package:libgit2dart/libgit2dart.dart';
 
 void main() {
   const sha = '9d81c715ff606057fa448e558c7458467a86c8c7';
@@ -20,8 +20,7 @@ void main() {
 
     test('returns sha hex string', () {
       final oid = Oid.fromSHA(sha);
-      final hex = oid.sha;
+      expect(oid.sha, equals(sha));
-      expect(hex, equals(sha));
     });
 
     group('compare', () {

test/reflog_test.dart

@@ -1,9 +1,7 @@
 import 'dart:io';
 
 import 'package:test/test.dart';
-import 'package:libgit2dart/src/repository.dart';
+import 'package:libgit2dart/libgit2dart.dart';
-import 'package:libgit2dart/src/reflog.dart';
-
 import 'helpers/util.dart';
 
 void main() {

test/repository_test.dart

@@ -214,6 +214,11 @@ void main() {
       });
 
       group('setHead', () {
+        late Reference head;
+
+        setUp(() => head = repo.head);
+        tearDown(() => head.free());
+
         test('successfully sets head when target is reference', () {
           expect(repo.head.name, 'refs/heads/master');
           expect(repo.head.target.sha, lastCommit);