feat(commit): add base bindings and api

lib/src/bindings/commit.dart

@@ -0,0 +1,91 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import '../error.dart';
+import 'libgit2_bindings.dart';
+import '../util.dart';
+
+/// Lookup a commit object from a repository.
+///
+/// The returned object should be released with `free()` when no longer needed.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_commit> lookup(Pointer<git_repository> repo, Pointer<git_oid> id) {
+  final out = calloc<Pointer<git_commit>>();
+  final error = libgit2.git_commit_lookup(out, repo, id);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out.value;
+  }
+}
+
+/// Get the encoding for the message of a commit, as a string representing a standard encoding name.
+///
+/// The encoding may be NULL if the encoding header in the commit is missing;
+/// 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 {
+    return result.cast<Utf8>().toDartString();
+  }
+}
+
+/// Get the full message of a commit.
+///
+/// The returned message will be slightly prettified by removing any potential leading newlines.
+String message(Pointer<git_commit> commit) {
+  final out = libgit2.git_commit_message(commit);
+  return out.cast<Utf8>().toDartString();
+}
+
+/// Get the id of a commit.
+Pointer<git_oid> id(Pointer<git_commit> commit) =>
+    libgit2.git_commit_id(commit);
+
+/// Get the number of parents of this commit.
+int parentCount(Pointer<git_commit> commit) =>
+    libgit2.git_commit_parentcount(commit);
+
+/// Get the oid of a specified parent for a commit.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_oid> parentId(Pointer<git_commit> commit, int n) {
+  final parentOid = libgit2.git_commit_parent_id(commit, n);
+
+  if (parentOid is int && parentOid as int < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return parentOid;
+  }
+}
+
+/// Get the commit time (i.e. committer time) of a commit.
+int time(Pointer<git_commit> commit) => libgit2.git_commit_time(commit);
+
+/// Get the committer of a commit.
+Pointer<git_signature> committer(Pointer<git_commit> commit) {
+  return libgit2.git_commit_committer(commit);
+}
+
+/// Get the author of a commit.
+Pointer<git_signature> author(Pointer<git_commit> commit) {
+  return libgit2.git_commit_author(commit);
+}
+
+/// Get the id of the tree pointed to by a commit.
+Pointer<git_oid> tree(Pointer<git_commit> commit) {
+  return libgit2.git_commit_tree_id(commit);
+}
+
+/// Get the repository that contains the commit.
+Pointer<git_repository> owner(Pointer<git_commit> commit) =>
+    libgit2.git_commit_owner(commit);
+
+/// Close an open commit.
+///
+/// IMPORTANT: It is necessary to call this method when you stop using a commit.
+/// Failure to do so will cause a memory leak.
+void free(Pointer<git_commit> commit) => libgit2.git_commit_free(commit);