refactor: use nullable strings instead of empty in arguments

lib/src/bindings/commit.dart

@@ -73,21 +73,19 @@ void annotatedFree(Pointer<git_annotated_commit> commit) {
 /// Throws a [LibGit2Error] if error occured.
 Pointer<git_oid> create(
   Pointer<git_repository> repo,
-  String updateRef,
+  String? updateRef,
   Pointer<git_signature> author,
   Pointer<git_signature> committer,
-  String messageEncoding,
+  String? messageEncoding,
   String message,
   Pointer<git_tree> tree,
   int parentCount,
   List<String> parents,
 ) {
   final out = calloc<git_oid>();
-  final updateRefC =
-      updateRef.isEmpty ? nullptr : updateRef.toNativeUtf8().cast<Int8>();
-  final messageEncodingC = messageEncoding.isEmpty
-      ? nullptr
-      : messageEncoding.toNativeUtf8().cast<Int8>();
+  final updateRefC = updateRef?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final messageEncodingC =
+      messageEncoding?.toNativeUtf8().cast<Int8>() ?? nullptr;
   final messageC = message.toNativeUtf8().cast<Int8>();
   Pointer<Pointer<git_commit>> parentsC =
       calloc.call<Pointer<git_commit>>(parentCount);

lib/src/bindings/remote.dart

@@ -296,7 +296,7 @@ void addPush(Pointer<git_repository> repo, String remote, String refspec) {
 void connect(
   Pointer<git_remote> remote,
   int direction,
-  String proxyOption,
+  String? proxyOption,
 ) {
   final callbacks = calloc<git_remote_callbacks>();
   final callbacksError = libgit2.git_remote_init_callbacks(
@@ -380,9 +380,9 @@ List<Map<String, dynamic>> lsRemotes(Pointer<git_remote> remote) {
 void fetch(
   Pointer<git_remote> remote,
   List<String> refspecs,
-  String reflogMessage,
+  String? reflogMessage,
   int prune,
-  String proxyOption,
+  String? proxyOption,
 ) {
   var refspecsC = calloc<git_strarray>();
   final refspecsPointers =
@@ -411,9 +411,7 @@ void fetch(
   opts.ref.prune = prune;
   opts.ref.proxy_opts = proxyOptions.ref;
 
-  final reflogMessageC = reflogMessage.isEmpty
-      ? nullptr
-      : reflogMessage.toNativeUtf8().cast<Int8>();
+  final reflogMessageC = reflogMessage?.toNativeUtf8().cast<Int8>() ?? nullptr;
 
   final error = libgit2.git_remote_fetch(
     remote,
@@ -428,6 +426,7 @@ void fetch(
   calloc.free(strArray);
   calloc.free(refspecsC);
   calloc.free(proxyOptions);
+  calloc.free(reflogMessageC);
   calloc.free(opts);
 
   if (error < 0) {
@@ -441,7 +440,7 @@ void fetch(
 void push(
   Pointer<git_remote> remote,
   List<String> refspecs,
-  String proxyOption,
+  String? proxyOption,
 ) {
   var refspecsC = calloc<git_strarray>();
   final refspecsPointers =
@@ -527,7 +526,7 @@ void prune(Pointer<git_remote> remote) {
 void free(Pointer<git_remote> remote) => libgit2.git_remote_free(remote);
 
 /// Initializes git_proxy_options structure.
-Pointer<git_proxy_options> _proxyOptionsInit(String proxyOption) {
+Pointer<git_proxy_options> _proxyOptionsInit(String? proxyOption) {
   final proxyOptions = calloc<git_proxy_options>();
   final proxyOptionsError =
       libgit2.git_proxy_options_init(proxyOptions, GIT_PROXY_OPTIONS_VERSION);
@@ -536,7 +535,7 @@ Pointer<git_proxy_options> _proxyOptionsInit(String proxyOption) {
     throw LibGit2Error(libgit2.git_error_last());
   }
 
-  if (proxyOption.isEmpty) {
+  if (proxyOption == null) {
     proxyOptions.ref.type = git_proxy_t.GIT_PROXY_NONE;
   } else if (proxyOption == 'auto') {
     proxyOptions.ref.type = git_proxy_t.GIT_PROXY_AUTO;

lib/src/bindings/repository.dart

@@ -51,12 +51,17 @@ Pointer<git_repository> openBare(String barePath) {
 /// The method will automatically detect if the repository is bare (if there is a repository).
 ///
 /// Throws a [LibGit2Error] if error occured.
-String discover(String startPath, String ceilingDirs) {
+String discover(String startPath, String? ceilingDirs) {
   final out = calloc<git_buf>(sizeOf<git_buf>());
   final startPathC = startPath.toNativeUtf8().cast<Int8>();
-  final ceilingDirsC = ceilingDirs.toNativeUtf8().cast<Int8>();
-  final error =
-      libgit2.git_repository_discover(out, startPathC, 0, ceilingDirsC);
+  final ceilingDirsC = ceilingDirs?.toNativeUtf8().cast<Int8>() ?? nullptr;
+
+  final error = libgit2.git_repository_discover(
+    out,
+    startPathC,
+    0,
+    ceilingDirsC,
+  );
 
   calloc.free(startPathC);
   calloc.free(ceilingDirsC);
@@ -77,24 +82,19 @@ Pointer<git_repository> init(
   String path,
   int flags,
   int mode,
-  String workdirPath,
-  String description,
-  String templatePath,
-  String initialHead,
-  String originUrl,
+  String? workdirPath,
+  String? description,
+  String? templatePath,
+  String? initialHead,
+  String? originUrl,
 ) {
   final out = calloc<Pointer<git_repository>>();
   final pathC = path.toNativeUtf8().cast<Int8>();
-  final workdirPathC =
-      workdirPath.isEmpty ? nullptr : workdirPath.toNativeUtf8().cast<Int8>();
-  final descriptionC =
-      description.isEmpty ? nullptr : description.toNativeUtf8().cast<Int8>();
-  final templatePathC =
-      templatePath.isEmpty ? nullptr : templatePath.toNativeUtf8().cast<Int8>();
-  final initialHeadC =
-      initialHead.isEmpty ? nullptr : initialHead.toNativeUtf8().cast<Int8>();
-  final originUrlC =
-      originUrl.isEmpty ? nullptr : originUrl.toNativeUtf8().cast<Int8>();
+  final workdirPathC = workdirPath?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final descriptionC = description?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final templatePathC = templatePath?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final initialHeadC = initialHead?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final originUrlC = originUrl?.toNativeUtf8().cast<Int8>() ?? nullptr;
   final opts = calloc<git_repository_init_options>();
   final optsError = libgit2.git_repository_init_options_init(
     opts,
@@ -139,14 +139,13 @@ Pointer<git_repository> clone(
   bool bare,
   Remote Function(Repository, String, String)? remote,
   Repository Function(String, bool)? repository,
-  String checkoutBranch,
+  String? checkoutBranch,
 ) {
   final out = calloc<Pointer<git_repository>>();
   final urlC = url.toNativeUtf8().cast<Int8>();
   final localPathC = localPath.toNativeUtf8().cast<Int8>();
-  final checkoutBranchC = checkoutBranch.isEmpty
-      ? nullptr
-      : checkoutBranch.toNativeUtf8().cast<Int8>();
+  final checkoutBranchC =
+      checkoutBranch?.toNativeUtf8().cast<Int8>() ?? nullptr;
 
   final cloneOptions = calloc<git_clone_options>();
   final cloneOptionsError =

lib/src/bindings/stash.dart

@@ -13,12 +13,11 @@ import '../util.dart';
 Pointer<git_oid> stash(
   Pointer<git_repository> repo,
   Pointer<git_signature> stasher,
-  String message,
+  String? message,
   int flags,
 ) {
   final out = calloc<git_oid>();
-  final messageC =
-      message.isNotEmpty ? message.toNativeUtf8().cast<Int8>() : nullptr;
+  final messageC = message?.toNativeUtf8().cast<Int8>() ?? nullptr;
   final error = libgit2.git_stash_save(out, repo, stasher, messageC, flags);
 
   if (error < 0) {