refactor: revert 'use ffi Arena for resource management'

lib/src/bindings/commit.dart

@@ -10,8 +10,7 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_commit> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_commit>>();
-    final out = arena<Pointer<git_commit>>();
   final error = libgit2.git_commit_lookup(out, repo, id);
 
   if (error < 0) {
@@ -19,7 +18,6 @@ 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.

lib/src/bindings/config.dart

@@ -11,8 +11,7 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> newConfig() {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
   final error = libgit2.git_config_new(out);
 
   if (error < 0) {
@@ -20,24 +19,23 @@ 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) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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
@@ -48,8 +46,7 @@ Pointer<git_config> open(String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> openDefault() {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
   final error = libgit2.git_config_open_default(out);
 
   if (error < 0) {
@@ -57,7 +54,6 @@ Pointer<git_config> openDefault() {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Locate the path to the global configuration file
@@ -74,17 +70,14 @@ Pointer<git_config> openDefault() {
 ///
 /// Throws an error if file has not been found.
 String findGlobal() {
-  return using((Arena arena) {
+  final out = calloc<git_buf>(sizeOf<git_buf>());
-    final out = arena<git_buf>(sizeOf<git_buf>());
   final error = libgit2.git_config_find_global(out);
-    final path = out.ref.ptr.cast<Utf8>().toDartString();
 
   if (error != 0) {
     throw Error();
   } else {
-      return path;
+    return out.ref.ptr.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Locate the path to the system configuration file
@@ -93,17 +86,14 @@ String findGlobal() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String findSystem() {
-  return using((Arena arena) {
+  final out = calloc<git_buf>();
-    final out = arena<git_buf>();
   final error = libgit2.git_config_find_system(out);
-    final path = out.ref.ptr.cast<Utf8>().toDartString();
 
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
-      return path;
+    return out.ref.ptr.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Locate the path to the global xdg compatible configuration file
@@ -113,17 +103,14 @@ String findSystem() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String findXdg() {
-  return using((Arena arena) {
+  final out = calloc<git_buf>();
-    final out = arena<git_buf>();
   final error = libgit2.git_config_find_xdg(out);
-    final path = out.ref.ptr.cast<Utf8>().toDartString();
 
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
-      return path;
+    return out.ref.ptr.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Create a snapshot of the configuration.
@@ -134,8 +121,7 @@ String findXdg() {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> snapshot(Pointer<git_config> config) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
   final error = libgit2.git_config_snapshot(out, config);
 
   if (error < 0) {
@@ -143,24 +129,23 @@ 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) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config_entry>>();
-    final out = arena<Pointer<git_config_entry>>();
+  final name = variable.toNativeUtf8().cast<Int8>();
-    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
   final error = libgit2.git_config_get_entry(out, cfg, name);
 
+  calloc.free(name);
+
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
     return out.value.ref.value.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Set the value of a boolean config variable in the config file with the
@@ -168,15 +153,15 @@ String getValue(Pointer<git_config> cfg, String variable) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setBool(Pointer<git_config> cfg, String variable, bool value) {
-  using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    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
@@ -184,14 +169,14 @@ 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) {
-  using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    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
@@ -199,22 +184,22 @@ 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) {
-  using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
+  final valueC = value.toNativeUtf8().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) {
-  return using((Arena arena) {
+  final iterator = calloc<Pointer<git_config_iterator>>();
-    final iterator = arena<Pointer<git_config_iterator>>();
+  final entry = calloc<Pointer<git_config_entry>>();
-    final entry = arena<Pointer<git_config_entry>>();
   libgit2.git_config_iterator_new(iterator, cfg);
   var error = 0;
   final entries = <String, String>{};
@@ -225,8 +210,10 @@ Map<String, String> getEntries(Pointer<git_config> cfg) {
         entry.value.ref.value.cast<Utf8>().toDartString();
   }
 
+  calloc.free(iterator);
+  calloc.free(entry);
+
   return entries;
-  });
 }
 
 /// Delete a config variable from the config file with the highest level
@@ -234,14 +221,14 @@ Map<String, String> getEntries(Pointer<git_config> cfg) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void delete(Pointer<git_config> cfg, String variable) {
-  using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    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
@@ -253,12 +240,10 @@ List<String> multivarValues(
   String variable,
   String? regexp,
 ) {
-  return using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
+  final regexpC = regexp?.toNativeUtf8().cast<Int8>() ?? nullptr;
-    final regexpC =
+  final iterator = calloc<Pointer<git_config_iterator>>();
-        regexp?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
+  final entry = calloc<Pointer<git_config_entry>>();
-    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>[];
@@ -272,8 +257,12 @@ 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
@@ -286,28 +275,27 @@ void setMultivar(
   String regexp,
   String value,
 ) {
-  using((Arena arena) {
+  final name = variable.toNativeUtf8().cast<Int8>();
-    final name = variable.toNativeUtf8(allocator: arena).cast<Int8>();
+  final regexpC = regexp.toNativeUtf8().cast<Int8>();
-    final regexpC = regexp.toNativeUtf8(allocator: arena).cast<Int8>();
+  final valueC = value.toNativeUtf8().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
 /// with the highest level (usually the local one).
 ///
 /// The regexp is applied case-sensitively on the value.
-void deleteMultivar(
+void deleteMultivar(Pointer<git_config> cfg, String variable, String regexp) {
-  Pointer<git_config> cfg,
+  final name = variable.toNativeUtf8().cast<Int8>();
-  String variable,
+  final regexpC = regexp.toNativeUtf8().cast<Int8>();
-  String regexp,
-) {
-  using((Arena arena) {
-    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

@@ -62,12 +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) {
-  return using((Arena arena) {
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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.
@@ -98,16 +98,16 @@ Pointer<git_index_entry> getByPath(
   String path,
   int stage,
 ) {
-  return using((Arena arena) {
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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.
@@ -152,14 +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) {
-  using((Arena arena) {
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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.
@@ -172,12 +172,10 @@ void addByPath(Pointer<git_index> index, String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void addAll(Pointer<git_index> index, List<String> pathspec) {
-  using((Arena arena) {
+  var pathspecC = calloc<git_strarray>();
-    var pathspecC = arena<git_strarray>();
+  final List<Pointer<Int8>> pathPointers =
-    final List<Pointer<Int8>> pathPointers = pathspec
+      pathspec.map((e) => e.toNativeUtf8().cast<Int8>()).toList();
-        .map((e) => e.toNativeUtf8(allocator: arena).cast<Int8>())
+  final Pointer<Pointer<Int8>> strArray = calloc(pathspec.length);
-        .toList();
-    final Pointer<Pointer<Int8>> strArray = arena(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
     strArray[i] = pathPointers[i];
@@ -194,10 +192,15 @@ void addAll(Pointer<git_index> index, List<String> pathspec) {
     nullptr,
   );
 
+  calloc.free(pathspecC);
+  for (var p in pathPointers) {
+    calloc.free(p);
+  }
+  calloc.free(strArray);
+
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   }
-  });
 }
 
 /// Write an existing index object from memory back to disk using an atomic file lock.
@@ -215,26 +218,24 @@ void write(Pointer<git_index> index) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void remove(Pointer<git_index> index, String path, int stage) {
-  using((Arena arena) {
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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) {
-  using((Arena arena) {
+  final pathspecC = calloc<git_strarray>();
-    final pathspecC = arena<git_strarray>();
+  final List<Pointer<Int8>> pathPointers =
-    final List<Pointer<Int8>> pathPointers = pathspec
+      pathspec.map((e) => e.toNativeUtf8().cast<Int8>()).toList();
-        .map((e) => e.toNativeUtf8(allocator: arena).cast<Int8>())
+  final Pointer<Pointer<Int8>> strArray = calloc(pathspec.length);
-        .toList();
-    final Pointer<Pointer<Int8>> strArray = arena(pathspec.length);
 
   for (var i = 0; i < pathspec.length; i++) {
     strArray[i] = pathPointers[i];
@@ -250,10 +251,15 @@ void removeAll(Pointer<git_index> index, List<String> pathspec) {
     nullptr,
   );
 
+  calloc.free(pathspecC);
+  for (var p in pathPointers) {
+    calloc.free(p);
+  }
+  calloc.free(strArray);
+
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   }
-  });
 }
 
 /// Get the repository this index relates to.

lib/src/bindings/oid.dart

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

lib/src/bindings/reference.dart

@@ -35,8 +35,7 @@ Pointer<git_oid> target(Pointer<git_reference> ref) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> resolve(Pointer<git_reference> ref) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
   final error = libgit2.git_reference_resolve(out, ref);
 
   if (error < 0) {
@@ -44,7 +43,6 @@ Pointer<git_reference> resolve(Pointer<git_reference> ref) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Lookup a reference by name in a repository.
@@ -55,17 +53,17 @@ Pointer<git_reference> resolve(Pointer<git_reference> ref) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> lookup(Pointer<git_repository> repo, String name) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    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.
@@ -75,27 +73,25 @@ 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) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    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) {
-  return using((Arena arena) {
+  var result = calloc<Int8>();
-    var result = arena<Int8>();
   result = libgit2.git_reference_name(ref);
 
   return result.cast<Utf8>().toDartString();
-  });
 }
 
 /// Get the reference's short name.
@@ -126,9 +122,8 @@ Pointer<git_reference> rename(
   bool force,
   String? logMessage,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final newNameC = newName.toNativeUtf8().cast<Int8>();
-    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(
@@ -139,23 +134,21 @@ Pointer<git_reference> rename(
     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.
 ///
-/// The string array will be filled with the names of all references;
-/// these values are owned by the user and should be free'd manually when no longer needed.
-///
 /// Throws a [LibGit2Error] if error occured.
 List<String> list(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  var array = calloc<git_strarray>();
-    var array = arena<git_strarray>();
   final error = libgit2.git_reference_list(array, repo);
   var result = <String>[];
 
@@ -168,24 +161,25 @@ 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) {
-  return using((Arena arena) {
+  final refname = name.toNativeUtf8().cast<Int8>();
-    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.
@@ -241,9 +235,8 @@ Pointer<git_reference> createDirect(
   bool force,
   String? logMessage,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    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(
@@ -255,12 +248,14 @@ Pointer<git_reference> createDirect(
     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.
@@ -292,9 +287,8 @@ Pointer<git_reference> createSymbolic(
   bool force,
   String? logMessage,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    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;
@@ -307,12 +301,15 @@ Pointer<git_reference> createSymbolic(
     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.
@@ -345,18 +342,17 @@ Pointer<git_reference> setTarget(
   Pointer<git_oid> oid,
   String? logMessage,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
-    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
@@ -375,20 +371,20 @@ Pointer<git_reference> setTargetSymbolic(
   String target,
   String? logMessage,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
+  final targetC = target.toNativeUtf8().cast<Int8>();
-    final targetC = target.toNativeUtf8(allocator: arena).cast<Int8>();
+  final logMessageC = logMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
-    final logMessageC =
+  final error =
-        logMessage?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
+      libgit2.git_reference_symbolic_set_target(out, ref, targetC, logMessageC);
-    final error = libgit2.git_reference_symbolic_set_target(
+
-        out, ref, targetC, logMessageC);
+  calloc.free(targetC);
+  calloc.free(logMessageC);
 
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   } else {
     return out.value;
   }
-  });
 }
 
 /// Compare two references.
@@ -407,12 +403,12 @@ 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) {
-  return using((Arena arena) {
+  final refname = name.toNativeUtf8().cast<Int8>();
-    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

@@ -13,17 +13,17 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reflog> read(Pointer<git_repository> repo, String name) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reflog>>();
-    final out = arena<Pointer<git_reflog>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    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

@@ -10,17 +10,17 @@ import '../util.dart';
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> open(String path) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_repository>>();
-    final out = arena<Pointer<git_repository>>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    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].
@@ -29,17 +29,17 @@ Pointer<git_repository> open(String path) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> openBare(String barePath) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_repository>>();
-    final out = arena<Pointer<git_repository>>();
+  final barePathC = barePath.toNativeUtf8().cast<Int8>();
-    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]
@@ -50,14 +50,15 @@ Pointer<git_repository> openBare(String barePath) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String discover(String startPath, String ceilingDirs) {
-  return using((Arena arena) {
+  final out = calloc<git_buf>(sizeOf<git_buf>());
-    final out = arena<git_buf>(sizeOf<git_buf>());
+  final startPathC = startPath.toNativeUtf8().cast<Int8>();
-    final startPathC = startPath.toNativeUtf8(allocator: arena).cast<Int8>();
+  final ceilingDirsC = ceilingDirs.toNativeUtf8().cast<Int8>();
-    final ceilingDirsC =
-        ceilingDirs.toNativeUtf8(allocator: arena).cast<Int8>();
   final error =
       libgit2.git_repository_discover(out, startPathC, 0, ceilingDirsC);
 
+  calloc.free(startPathC);
+  calloc.free(ceilingDirsC);
+
   if (error == git_error_code.GIT_ENOTFOUND) {
     return '';
   } else if (error < 0) {
@@ -65,25 +66,24 @@ String discover(String startPath, String ceilingDirs) {
   } else {
     return out.ref.ptr.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Creates a new Git repository in the given folder.
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> init(String path, bool isBare) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_repository>>();
-    final out = arena<Pointer<git_repository>>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
-    final pathC = path.toNativeUtf8(allocator: arena).cast<Int8>();
   final isBareC = isBare ? 1 : 0;
   final error = libgit2.git_repository_init(out, pathC, isBareC);
 
+  calloc.free(pathC);
+
   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
@@ -125,15 +125,14 @@ String getNamespace(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setNamespace(Pointer<git_repository> repo, String? namespace) {
-  using((Arena arena) {
+  final nmspace = namespace?.toNativeUtf8().cast<Int8>() ?? nullptr;
-    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.
@@ -165,8 +164,7 @@ bool isEmpty(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_reference> head(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_reference>>();
-    final out = arena<Pointer<git_reference>>();
   final error = libgit2.git_repository_head(out, repo);
 
   if (error < 0) {
@@ -174,7 +172,6 @@ Pointer<git_reference> head(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Check if a repository's HEAD is detached.
@@ -213,20 +210,19 @@ 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) {
-  using((Arena arena) {
+  final nameC = name?.toNativeUtf8().cast<Int8>() ?? nullptr;
-    final nameC = name?.toNativeUtf8(allocator: arena).cast<Int8>() ?? nullptr;
+  final emailC = email?.toNativeUtf8().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) {
-  return using((Arena arena) {
+  final name = calloc<Pointer<Int8>>();
-    final name = arena<Pointer<Int8>>();
+  final email = calloc<Pointer<Int8>>();
-    final email = arena<Pointer<Int8>>();
   libgit2.git_repository_ident(name, email, repo);
   var identity = <String, String>{};
 
@@ -237,8 +233,10 @@ 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.
@@ -250,8 +248,7 @@ Map<String, String> identity(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> config(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
   final error = libgit2.git_repository_config(out, repo);
 
   if (error < 0) {
@@ -259,7 +256,6 @@ Pointer<git_config> config(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Get a snapshot of the repository's configuration.
@@ -271,8 +267,7 @@ Pointer<git_config> config(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_config>>();
-    final out = arena<Pointer<git_config>>();
   final error = libgit2.git_repository_config_snapshot(out, repo);
 
   if (error < 0) {
@@ -280,7 +275,6 @@ Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Get the Index file for this repository.
@@ -292,8 +286,7 @@ Pointer<git_config> configSnapshot(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_index> index(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_index>>();
-    final out = arena<Pointer<git_index>>();
   final error = libgit2.git_repository_index(out, repo);
 
   if (error < 0) {
@@ -301,7 +294,6 @@ Pointer<git_index> index(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Determine if the repository was a shallow clone.
@@ -328,8 +320,7 @@ bool isWorktree(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 String message(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<git_buf>(sizeOf<git_buf>());
-    final out = arena<git_buf>(sizeOf<git_buf>());
   final error = libgit2.git_repository_message(out, repo);
 
   if (error < 0) {
@@ -337,7 +328,6 @@ String message(Pointer<git_repository> repo) {
   } else {
     return out.ref.ptr.cast<Utf8>().toDartString();
   }
-  });
 }
 
 /// Remove git's prepared message.
@@ -354,8 +344,7 @@ void removeMessage(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_odb> odb(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_odb>>();
-    final out = arena<Pointer<git_odb>>();
   final error = libgit2.git_repository_odb(out, repo);
 
   if (error < 0) {
@@ -363,7 +352,6 @@ Pointer<git_odb> odb(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Get the Reference Database Backend for this repository.
@@ -376,8 +364,7 @@ Pointer<git_odb> odb(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_refdb>>();
-    final out = arena<Pointer<git_refdb>>();
   final error = libgit2.git_repository_refdb(out, repo);
 
   if (error < 0) {
@@ -385,7 +372,6 @@ Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Make the repository HEAD point to the specified reference.
@@ -401,14 +387,14 @@ Pointer<git_refdb> refdb(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 void setHead(Pointer<git_repository> repo, String ref) {
-  using((Arena arena) {
+  final refname = ref.toNativeUtf8().cast<Int8>();
-    final refname = ref.toNativeUtf8(allocator: arena).cast<Int8>();
   final error = libgit2.git_repository_set_head(repo, refname);
 
+  calloc.free(refname);
+
   if (error < 0) {
     throw LibGit2Error(libgit2.git_error_last());
   }
-  });
 }
 
 /// Make the repository HEAD directly point to the commit.
@@ -462,16 +448,19 @@ void setWorkdir(
   String path,
   bool updateGitlink,
 ) {
-  using((Arena arena) {
+  final workdir = path.toNativeUtf8().cast<Int8>();
-    final workdir = path.toNativeUtf8(allocator: arena).cast<Int8>();
   final updateGitlinkC = updateGitlink ? 1 : 0;
-    final error =
+  final error = libgit2.git_repository_set_workdir(
-        libgit2.git_repository_set_workdir(repo, workdir, updateGitlinkC);
+    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
@@ -511,8 +500,7 @@ String workdir(Pointer<git_repository> repo) {
 ///
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_repository>>();
-    final out = arena<Pointer<git_repository>>();
   final error = libgit2.git_repository_wrap_odb(out, odb);
 
   if (error < 0) {
@@ -520,7 +508,6 @@ Pointer<git_repository> wrapODB(Pointer<git_odb> odb) {
   } else {
     return out.value;
   }
-  });
 }
 
 /// Find a single object, as specified by a [spec] string.
@@ -532,21 +519,21 @@ Pointer<git_object> revParseSingle(
   Pointer<git_repository> repo,
   String spec,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_object>>();
-    final out = arena<Pointer<git_object>>();
+  final specC = spec.toNativeUtf8().cast<Int8>();
-    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;
   }
-  });
 }
 
 /// Free a previously allocated repository.

lib/src/bindings/signature.dart

@@ -16,36 +16,38 @@ Pointer<git_signature> create(
   int time,
   int offset,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_signature>>();
-    final out = arena<Pointer<git_signature>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
+  final emailC = email.toNativeUtf8().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) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_signature>>();
-    final out = arena<Pointer<git_signature>>();
+  final nameC = name.toNativeUtf8().cast<Int8>();
-    final nameC = name.toNativeUtf8(allocator: arena).cast<Int8>();
+  final emailC = email.toNativeUtf8().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

@@ -11,8 +11,7 @@ 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) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_tree>>();
-    final out = arena<Pointer<git_tree>>();
   final error = libgit2.git_tree_lookup(out, repo, id);
 
   if (error < 0) {
@@ -20,7 +19,6 @@ 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).
@@ -31,8 +29,7 @@ Pointer<git_tree> lookupPrefix(
   Pointer<git_oid> id,
   int len,
 ) {
-  return using((Arena arena) {
+  final out = calloc<Pointer<git_tree>>();
-    final out = arena<Pointer<git_tree>>();
   final error = libgit2.git_tree_lookup_prefix(out, repo, id, len);
 
   if (error < 0) {
@@ -40,13 +37,7 @@ Pointer<git_tree> lookupPrefix(
   } else {
     return out.value;
   }
-  });
 }
 
-/// Close an open tree.
+/// Close an open tree to release memory.
-///
-/// You can no longer use the git_tree pointer after this call.
-///
-/// IMPORTANT: You MUST call this method when you stop using a tree to release memory.
-/// Failure to do so will cause a memory leak.
 void free(Pointer<git_tree> tree) => libgit2.git_tree_free(tree);