feat(packbuilder): add bindings and api

lib/src/bindings/packbuilder.dart

@@ -0,0 +1,107 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import 'libgit2_bindings.dart';
+import '../error.dart';
+import '../util.dart';
+
+/// Initialize a new packbuilder.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_packbuilder> init(Pointer<git_repository> repo) {
+  final out = calloc<Pointer<git_packbuilder>>();
+  final error = libgit2.git_packbuilder_new(out, repo);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out.value;
+  }
+}
+
+/// Insert a single object.
+///
+/// For an optimal pack it's mandatory to insert objects in recency order,
+/// commits followed by trees and blobs.
+///
+/// Throws a [LibGit2Error] if error occured.
+void add({
+  required Pointer<git_packbuilder> packbuilderPointer,
+  required Pointer<git_oid> oidPointer,
+}) {
+  final error = libgit2.git_packbuilder_insert(
+    packbuilderPointer,
+    oidPointer,
+    nullptr,
+  );
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Recursively insert an object and its referenced objects.
+///
+/// Insert the object as well as any object it references.
+///
+/// Throws a [LibGit2Error] if error occured.
+void addRecursively({
+  required Pointer<git_packbuilder> packbuilderPointer,
+  required Pointer<git_oid> oidPointer,
+}) {
+  final error = libgit2.git_packbuilder_insert_recur(
+    packbuilderPointer,
+    oidPointer,
+    nullptr,
+  );
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Write the new pack and corresponding index file to path.
+///
+/// Throws a [LibGit2Error] if error occured.
+void write({
+  required Pointer<git_packbuilder> packbuilderPointer,
+  String? path,
+}) {
+  final pathC = path?.toNativeUtf8().cast<Int8>() ?? nullptr;
+  final error = libgit2.git_packbuilder_write(
+    packbuilderPointer,
+    pathC,
+    0,
+    nullptr,
+    nullptr,
+  );
+
+  calloc.free(pathC);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Get the total number of objects the packbuilder will write out.
+int length(Pointer<git_packbuilder> pb) {
+  return libgit2.git_packbuilder_object_count(pb);
+}
+
+/// Get the number of objects the packbuilder has already written out.
+int writtenCount(Pointer<git_packbuilder> pb) {
+  return libgit2.git_packbuilder_written(pb);
+}
+
+/// Set number of threads to spawn.
+///
+/// By default, libgit2 won't spawn any threads at all; when set to 0,
+/// libgit2 will autodetect the number of CPUs.
+int setThreads({
+  required Pointer<git_packbuilder> packbuilderPointer,
+  required int number,
+}) {
+  return libgit2.git_packbuilder_set_threads(packbuilderPointer, number);
+}
+
+/// Free the packbuilder and all associated data.
+void free(Pointer<git_packbuilder> pb) => libgit2.git_packbuilder_free(pb);