feat(repository): add ability to check status of repo and single file

lib/src/bindings/status.dart

@@ -0,0 +1,81 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import 'package:libgit2dart/libgit2dart.dart';
+import 'libgit2_bindings.dart';
+import '../error.dart';
+import '../util.dart';
+
+/// Gather file status information and populate the git_status_list.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_status_list> listNew(Pointer<git_repository> repo) {
+  final out = calloc<Pointer<git_status_list>>();
+  final error = libgit2.git_status_list_new(out, repo, nullptr);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out.value;
+  }
+}
+
+/// Gets the count of status entries in this list.
+///
+/// If there are no changes in status (at least according the options given when
+/// the status list was created), this can return 0.
+int listEntryCount(Pointer<git_status_list> statuslist) {
+  return libgit2.git_status_list_entrycount(statuslist);
+}
+
+/// Get a pointer to one of the entries in the status list.
+///
+/// The entry is not modifiable and should not be freed.
+///
+/// Throws [RangeError] if position is out of bounds
+Pointer<git_status_entry> getByIndex(
+  Pointer<git_status_list> statuslist,
+  int idx,
+) {
+  final result = libgit2.git_status_byindex(statuslist, idx);
+
+  if (result == nullptr) {
+    throw RangeError('Out of bounds');
+  } else {
+    return result;
+  }
+}
+
+/// Get file status for a single file.
+///
+/// This tries to get status for the filename that you give. If no files match that name
+/// (in either the HEAD, index, or working directory), this returns GIT_ENOTFOUND.
+///
+/// If the name matches multiple files (for example, if the path names a directory or if
+/// running on a case- insensitive filesystem and yet the HEAD has two entries that both
+/// match the path), then this returns GIT_EAMBIGUOUS because it cannot give correct results.
+///
+/// This does not do any sort of rename detection. Renames require a set of targets and because
+/// of the path filtering, there is not enough information to check renames correctly. To check
+/// file status with rename detection, there is no choice but to do a full listNew
+/// and scan through looking for the path that you are interested in.
+///
+/// Throws a [LibGit2Error] if error occured.
+int file(Pointer<git_repository> repo, String path) {
+  final out = calloc<Uint32>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
+  final error = libgit2.git_status_file(out, repo, pathC);
+
+  calloc.free(pathC);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    final result = out.value;
+    calloc.free(out);
+    return result;
+  }
+}
+
+/// Free an existing status list.
+void listFree(Pointer<git_status_list> statuslist) =>
+    libgit2.git_status_list_free(statuslist);

lib/src/git_types.dart

@@ -23,15 +23,10 @@ class GitFilemode {
   final int _value;
 
   static const unreadable = GitFilemode._(0);
-
   static const tree = GitFilemode._(16384);
-
   static const blob = GitFilemode._(33188);
-
   static const blobExecutable = GitFilemode._(33261);
-
   static const link = GitFilemode._(40960);
-
   static const commit = GitFilemode._(57344);
 
   int get value => _value;
@@ -117,10 +112,38 @@ class GitBranch {
   final int _value;
 
   static const local = GitBranch._(1);
-
   static const remote = GitBranch._(2);
-
   static const all = GitBranch._(3);
 
   int get value => _value;
 }
+
+/// Status flags for a single file.
+///
+/// A combination of these values will be returned to indicate the status of
+/// a file.  Status compares the working directory, the index, and the
+/// current HEAD of the repository.  The `GitStatus.index` set of flags
+/// represents the status of file in the index relative to the HEAD, and the
+/// `GitStatus.wt` set of flags represent the status of the file in the
+/// working directory relative to the index.
+class GitStatus {
+  const GitStatus._(this._value);
+  final int _value;
+
+  static const current = GitStatus._(0);
+  static const indexNew = GitStatus._(1);
+  static const indexModified = GitStatus._(2);
+  static const indexDeleted = GitStatus._(4);
+  static const indexRenamed = GitStatus._(8);
+  static const indexTypeChange = GitStatus._(16);
+  static const wtNew = GitStatus._(128);
+  static const wtModified = GitStatus._(256);
+  static const wtDeleted = GitStatus._(512);
+  static const wtTypeChange = GitStatus._(1024);
+  static const wtRenamed = GitStatus._(2048);
+  static const wtUnreadable = GitStatus._(4096);
+  static const ignored = GitStatus._(16384);
+  static const conflicted = GitStatus._(32768);
+
+  int get value => _value;
+}

lib/src/repository.dart

@@ -1,8 +1,10 @@
 import 'dart:ffi';
+import 'package:ffi/ffi.dart';
 import 'bindings/libgit2_bindings.dart';
 import 'bindings/repository.dart' as bindings;
 import 'bindings/merge.dart' as merge_bindings;
 import 'bindings/object.dart' as object_bindings;
+import 'bindings/status.dart' as status_bindings;
 import 'branch.dart';
 import 'commit.dart';
 import 'config.dart';
@@ -459,4 +461,37 @@ class Repository {
 
   /// Returns a [Branches] object.
   Branches get branches => Branches(this);
+
+  /// Checks status of the repository and returns map of file paths and their statuses.
+  ///
+  /// Returns empty map if there are no changes in statuses.
+  Map<String, int> get status {
+    var result = <String, int>{};
+    var list = status_bindings.listNew(_repoPointer);
+    var count = status_bindings.listEntryCount(list);
+
+    for (var i = 0; i < count; i++) {
+      final entry = status_bindings.getByIndex(list, i);
+      if (entry.ref.head_to_index != nullptr) {
+        final path = entry.ref.head_to_index.ref.old_file.path
+            .cast<Utf8>()
+            .toDartString();
+        result[path] = entry.ref.status;
+      }
+    }
+
+    status_bindings.listFree(list);
+
+    return result;
+  }
+
+  /// Returns file status for a single file.
+  ///
+  /// This does not do any sort of rename detection. Renames require a set of targets and because
+  /// of the path filtering, there is not enough information to check renames correctly. To check
+  /// file status with rename detection, there is no choice but to do a full [status] and scan
+  /// through looking for the path that you are interested in.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  int statusFile(String path) => status_bindings.file(_repoPointer, path);
 }