feat(treebuilder): add bindings and api

lib/src/bindings/treebuilder.dart

@@ -0,0 +1,126 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import '../error.dart';
+import 'libgit2_bindings.dart';
+import '../util.dart';
+
+/// Create a new tree builder.
+///
+/// The tree builder can be used to create or modify trees in memory and write them
+/// as tree objects to the database.
+///
+/// If the source parameter is not null, the tree builder will be initialized with
+/// the entries of the given tree.
+///
+/// If the source parameter is null, the tree builder will start with no entries
+/// and will have to be filled manually.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_treebuilder> create(
+  Pointer<git_repository> repo,
+  Pointer<git_tree> source,
+) {
+  final out = calloc<Pointer<git_treebuilder>>();
+  final error = libgit2.git_treebuilder_new(out, repo, source);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out.value;
+  }
+}
+
+/// Write the contents of the tree builder as a tree object.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_oid> write(Pointer<git_treebuilder> bld) {
+  final out = calloc<git_oid>();
+  final error = libgit2.git_treebuilder_write(out, bld);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out;
+  }
+}
+
+/// Clear all the entires in the builder.
+///
+/// Throws a [LibGit2Error] if error occured.
+void clear(Pointer<git_treebuilder> bld) {
+  final error = libgit2.git_treebuilder_clear(bld);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Get the number of entries listed in a treebuilder.
+int entryCount(Pointer<git_treebuilder> bld) =>
+    libgit2.git_treebuilder_entrycount(bld);
+
+/// Get an entry from the builder from its filename.
+///
+/// The returned entry is owned by the builder and should not be freed manually.
+///
+/// Throws [ArgumentError] if nothing found for provided filename.
+Pointer<git_tree_entry> getByFilename(
+  Pointer<git_treebuilder> bld,
+  String filename,
+) {
+  final filenameC = filename.toNativeUtf8().cast<Int8>();
+  final result = libgit2.git_treebuilder_get(bld, filenameC);
+
+  calloc.free(filenameC);
+
+  if (result == nullptr) {
+    throw ArgumentError.value('$filename was not found');
+  } else {
+    return result;
+  }
+}
+
+/// Add or update an entry to the builder.
+///
+/// Insert a new entry for filename in the builder with the given attributes.
+///
+/// If an entry named filename already exists, its attributes will be updated with
+/// the given ones.
+///
+/// By default the entry that you are inserting will be checked for validity;
+/// that it exists in the object database and is of the correct type.
+///
+/// Throws a [LibGit2Error] if error occured.
+void add(
+  Pointer<git_treebuilder> bld,
+  String filename,
+  Pointer<git_oid> id,
+  int filemode,
+) {
+  final filenameC = filename.toNativeUtf8().cast<Int8>();
+  final error =
+      libgit2.git_treebuilder_insert(nullptr, bld, filenameC, id, filemode);
+
+  calloc.free(filenameC);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Remove an entry from the builder by its filename.
+///
+/// Throws a [LibGit2Error] if error occured.
+void remove(Pointer<git_treebuilder> bld, String filename) {
+  final filenameC = filename.toNativeUtf8().cast<Int8>();
+  final error = libgit2.git_treebuilder_remove(bld, filenameC);
+
+  calloc.free(filenameC);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+}
+
+/// Free a tree builder to release memory.
+void free(Pointer<git_treebuilder> bld) => libgit2.git_treebuilder_free(bld);

lib/src/tree.dart

@@ -52,6 +52,12 @@ class Tree {
     }
   }
 
+  /// Returns the Oid of a tree.
+  Oid get id => Oid(bindings.id(_treePointer));
+
+  /// Get the number of entries listed in a tree.
+  int get length => bindings.entryCount(_treePointer);
+
   /// Releases memory allocated for tree object.
   void free() => bindings.free(_treePointer);
 }

lib/src/treebuilder.dart

@@ -0,0 +1,77 @@
+import 'dart:ffi';
+import 'bindings/libgit2_bindings.dart';
+import 'bindings/treebuilder.dart' as bindings;
+import 'repository.dart';
+import 'oid.dart';
+import 'enums.dart';
+import 'tree.dart';
+import 'util.dart';
+
+class TreeBuilder {
+  /// Initializes a new instance of [TreeBuilder] class from provided
+  /// [Repository] and optional [Tree] objects.
+  ///
+  /// Should be freed with `free()` to release allocated memory.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  TreeBuilder(Repository repo, [Tree? tree]) {
+    _treeBuilderPointer = bindings.create(
+      repo.pointer,
+      tree?.pointer ?? nullptr,
+    );
+  }
+
+  late final Pointer<git_treebuilder> _treeBuilderPointer;
+
+  /// Pointer to memory address for allocated tree builder object.
+  Pointer<git_treebuilder> get pointer => _treeBuilderPointer;
+
+  /// Returns the number of entries listed in a tree builder.
+  int get length => bindings.entryCount(_treeBuilderPointer);
+
+  /// Writes the contents of the tree builder as a tree object.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  Oid write() => Oid(bindings.write(_treeBuilderPointer));
+
+  /// Clears all the entires in the tree builder.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  void clear() => bindings.clear(_treeBuilderPointer);
+
+  /// Returns an entry from the tree builder from its filename.
+  ///
+  /// The returned entry is owned by the tree builder and should not be freed manually.
+  ///
+  /// Throws [ArgumentError] if nothing found for provided filename.
+  TreeEntry operator [](String filename) {
+    return TreeEntry(bindings.getByFilename(_treeBuilderPointer, filename));
+  }
+
+  /// Adds or updates an entry to the tree builder with the given attributes.
+  ///
+  /// If an entry named filename already exists, its attributes will be updated with
+  /// the given ones.
+  ///
+  /// By default the entry that you are inserting will be checked for validity;
+  /// that it exists in the object database and is of the correct type.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  void add(String filename, Oid id, GitFilemode filemode) {
+    bindings.add(
+      _treeBuilderPointer,
+      filename,
+      id.pointer,
+      gitFilemodeToInt(filemode),
+    );
+  }
+
+  /// Removes an entry from the tree builder by its filename.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  void remove(String filename) =>
+      bindings.remove(_treeBuilderPointer, filename);
+
+  /// Releases memory allocated for tree builder object.
+  void free() => bindings.free(_treeBuilderPointer);
+}