feat(blame): add bindings and api

lib/src/bindings/blame.dart

@@ -0,0 +1,104 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import '../error.dart';
+import '../oid.dart';
+import '../util.dart';
+import 'libgit2_bindings.dart';
+
+/// Get the blame for a single file.
+///
+/// Throws a [LibGit2Error] if error occured.
+Pointer<git_blame> file({
+  required Pointer<git_repository> repoPointer,
+  required String path,
+  int? flags,
+  int? minMatchCharacters,
+  Oid? newestCommit,
+  Oid? oldestCommit,
+  int? minLine,
+  int? maxLine,
+}) {
+  final out = calloc<Pointer<git_blame>>();
+  final pathC = path.toNativeUtf8().cast<Int8>();
+  final options = calloc<git_blame_options>();
+  final optionsError = libgit2.git_blame_options_init(
+    options,
+    GIT_BLAME_OPTIONS_VERSION,
+  );
+
+  if (optionsError < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  }
+
+  if (flags != null) {
+    options.ref.flags = flags;
+  }
+
+  if (minMatchCharacters != null) {
+    options.ref.min_match_characters = minMatchCharacters;
+  }
+
+  if (newestCommit != null) {
+    options.ref.newest_commit = newestCommit.pointer.ref;
+  }
+
+  if (oldestCommit != null) {
+    options.ref.oldest_commit = oldestCommit.pointer.ref;
+  }
+
+  if (minLine != null) {
+    options.ref.min_line = minLine;
+  }
+
+  if (maxLine != null) {
+    options.ref.max_line = maxLine;
+  }
+
+  final error = libgit2.git_blame_file(out, repoPointer, pathC, options);
+
+  if (error < 0) {
+    throw LibGit2Error(libgit2.git_error_last());
+  } else {
+    return out.value;
+  }
+}
+
+/// Gets the number of hunks that exist in the blame structure.
+int hunkCount(Pointer<git_blame> blame) {
+  return libgit2.git_blame_get_hunk_count(blame);
+}
+
+/// Gets the blame hunk at the given index.
+///
+/// Throws [RangeError] if index out of range.
+Pointer<git_blame_hunk> getHunkByIndex({
+  required Pointer<git_blame> blamePointer,
+  required int index,
+}) {
+  final result = libgit2.git_blame_get_hunk_byindex(blamePointer, index);
+
+  if (result == nullptr) {
+    throw RangeError('$index is out of bounds');
+  } else {
+    return result;
+  }
+}
+
+/// Gets the hunk that relates to the given line number (1-based) in the newest commit.
+///
+/// Throws [RangeError] if [lineNumber] is out of range.
+Pointer<git_blame_hunk> getHunkByLine({
+  required Pointer<git_blame> blamePointer,
+  required int lineNumber,
+}) {
+  final result = libgit2.git_blame_get_hunk_byline(blamePointer, lineNumber);
+
+  if (result == nullptr) {
+    throw RangeError('$lineNumber is out of bounds');
+  } else {
+    return result;
+  }
+}
+
+/// Free memory allocated for blame object.
+void free(Pointer<git_blame> blame) => libgit2.git_blame_free(blame);

lib/src/blame.dart

@@ -0,0 +1,172 @@
+import 'dart:collection';
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import 'bindings/libgit2_bindings.dart';
+import 'bindings/blame.dart' as bindings;
+import 'util.dart';
+import 'git_types.dart';
+import 'oid.dart';
+import 'repository.dart';
+import 'signature.dart';
+
+class Blame with IterableMixin<BlameHunk> {
+  /// Initializes a new instance of the [Blame] class from
+  /// provided pointer to blame object in memory.
+  Blame(this._blamePointer);
+
+  /// Initializes a new instance of the [Blame] class by getting
+  /// the blame for a single file.
+  ///
+  /// [flags] is a combination of [GitBlameFlag]s.
+  ///
+  /// [minMatchCharacters] is the lower bound on the number of alphanumeric
+  /// characters that must be detected as moving/copying within a file for
+  /// it to associate those lines with the parent commit. The default value is 20.
+  /// This value only takes effect if any of the [GitBlameFlag.trackCopies*]
+  /// flags are specified.
+  ///
+  /// [newestCommit] is the id of the newest commit to consider. The default is HEAD.
+  ///
+  /// [oldestCommit] is the id of the oldest commit to consider. The default is the
+  /// first commit encountered with no parent.
+  ///
+  /// [minLine] is the first line in the file to blame. The default is 1
+  /// (line numbers start with 1).
+  ///
+  /// [maxLine] is the last line in the file to blame. The default is the last
+  /// line of the file.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  Blame.file({
+    required Repository repo,
+    required String path,
+    Set<GitBlameFlag> flags = const {GitBlameFlag.normal},
+    int? minMatchCharacters,
+    Oid? newestCommit,
+    Oid? oldestCommit,
+    int? minLine,
+    int? maxLine,
+  }) {
+    libgit2.git_libgit2_init();
+
+    final int flagsInt =
+        flags.fold(0, (previousValue, e) => previousValue | e.value);
+
+    _blamePointer = bindings.file(
+      repoPointer: repo.pointer,
+      path: path,
+      flags: flagsInt,
+      minMatchCharacters: minMatchCharacters,
+      newestCommit: newestCommit,
+      oldestCommit: oldestCommit,
+      minLine: minLine,
+      maxLine: maxLine,
+    );
+  }
+
+  /// Pointer to memory address for allocated blame object.
+  late final Pointer<git_blame> _blamePointer;
+
+  /// Returns the blame hunk at the given index.
+  ///
+  /// Throws [RangeError] if index out of range.
+  BlameHunk operator [](int index) {
+    return BlameHunk(bindings.getHunkByIndex(
+      blamePointer: _blamePointer,
+      index: index,
+    ));
+  }
+
+  /// Gets the hunk that relates to the given line number (1-based) in the newest commit.
+  ///
+  /// Throws [RangeError] if [lineNumber] is out of range.
+  BlameHunk forLine(int lineNumber) {
+    return BlameHunk(bindings.getHunkByLine(
+      blamePointer: _blamePointer,
+      lineNumber: lineNumber,
+    ));
+  }
+
+  /// Releases memory allocated for blame object.
+  void free() => bindings.free(_blamePointer);
+
+  @override
+  Iterator<BlameHunk> get iterator => _BlameIterator(_blamePointer);
+}
+
+class BlameHunk {
+  /// Initializes a new instance of the [BlameHunk] class from
+  /// provided pointer to blame hunk object in memory.
+  const BlameHunk(this._blameHunkPointer);
+
+  /// Pointer to memory address for allocated blame hunk object.
+  final Pointer<git_blame_hunk> _blameHunkPointer;
+
+  /// Returns the number of lines in this hunk.
+  int get linesCount => _blameHunkPointer.ref.lines_in_hunk;
+
+  /// Checks if the hunk has been tracked to a boundary commit
+  /// (the root, or the commit specified in [oldestCommit] argument)
+  bool get isBoundary {
+    return _blameHunkPointer.ref.boundary == 1 ? true : false;
+  }
+
+  /// Returns the 1-based line number where this hunk begins, in the final
+  /// version of the file.
+  int get finalStartLineNumber => _blameHunkPointer.ref.final_start_line_number;
+
+  /// Returns the author of [finalCommitId]. If [GitBlameFlag.useMailmap] has been
+  /// specified, it will contain the canonical real name and email address.
+  Signature get finalCommitter =>
+      Signature(_blameHunkPointer.ref.final_signature);
+
+  /// Returns the [Oid] of the commit where this line was last changed.
+  Oid get finalCommitId => Oid.fromRaw(_blameHunkPointer.ref.final_commit_id);
+
+  /// Returns the 1-based line number where this hunk begins, in the file
+  /// named by [originPath] in the commit specified by [originCommitId].
+  int get originStartLineNumber => _blameHunkPointer.ref.orig_start_line_number;
+
+  /// Returns the author of [originCommitId]. If [GitBlameFlag.useMailmap] has been
+  /// specified, it will contain the canonical real name and email address.
+  Signature get originCommitter =>
+      Signature(_blameHunkPointer.ref.orig_signature);
+
+  /// Returns the [Oid] of the commit where this hunk was found. This will usually be
+  /// the same as [finalCommitId], except when [GitBlameFlag.trackCopiesAnyCommitCopies]
+  /// been specified.
+  Oid get originCommitId => Oid.fromRaw(_blameHunkPointer.ref.orig_commit_id);
+
+  /// Returns the path to the file where this hunk originated, as of the commit
+  /// specified by [originCommitId].
+  String get originPath =>
+      _blameHunkPointer.ref.orig_path.cast<Utf8>().toDartString();
+}
+
+class _BlameIterator implements Iterator<BlameHunk> {
+  _BlameIterator(this._blamePointer) {
+    count = bindings.hunkCount(_blamePointer);
+  }
+
+  final Pointer<git_blame> _blamePointer;
+  BlameHunk? currentHunk;
+  late final int count;
+  int index = 0;
+
+  @override
+  BlameHunk get current => currentHunk!;
+
+  @override
+  bool moveNext() {
+    if (index == count) {
+      return false;
+    } else {
+      currentHunk = BlameHunk(bindings.getHunkByIndex(
+        blamePointer: _blamePointer,
+        index: index,
+      ));
+      index++;
+      return true;
+    }
+  }
+}

lib/src/git_types.dart

@@ -1384,3 +1384,72 @@ class GitAttributeCheck {
   @override
   String toString() => 'GitAttributeCheck.$_name';
 }
+
+/// Flags for indicating option behavior for git blame APIs.
+class GitBlameFlag {
+  const GitBlameFlag._(this._value, this._name);
+  final int _value;
+  final String _name;
+
+  /// Normal blame, the default.
+  static const normal = GitBlameFlag._(0, 'normal');
+
+  /// Track lines that have moved within a file (like `git blame -M`).
+  ///
+  /// This is not yet implemented and reserved for future use.
+  static const trackCopiesSameFile = GitBlameFlag._(1, 'trackCopiesSameFile');
+
+  /// Track lines that have moved across files in the same commit
+  /// (like `git blame -C`).
+  ///
+  /// This is not yet implemented and reserved for future use.
+  static const trackCopiesSameCommitMoves =
+      GitBlameFlag._(2, 'trackCopiesSameCommitMoves');
+
+  /// Track lines that have been copied from another file that exists
+  /// in the same commit (like `git blame -CC`).  Implies SAME_FILE.
+  ///
+  /// This is not yet implemented and reserved for future use.
+  static const trackCopiesSameCommitCopies = GitBlameFlag._(
+    4,
+    'trackCopiesSameCommitCopies',
+  );
+
+  /// Track lines that have been copied from another file that exists in
+  /// *any* commit (like `git blame -CCC`).  Implies SAME_COMMIT_COPIES.
+  ///
+  /// This is not yet implemented and reserved for future use.
+  static const trackCopiesAnyCommitCopies = GitBlameFlag._(
+    8,
+    'trackCopiesAnyCommitCopies',
+  );
+
+  /// Restrict the search of commits to those reachable following only
+  /// the first parents.
+  static const firstParent = GitBlameFlag._(16, 'firstParent');
+
+  /// Use mailmap file to map author and committer names and email
+  /// addresses to canonical real names and email addresses. The
+  /// mailmap will be read from the working directory, or HEAD in a
+  /// bare repository.
+  static const useMailmap = GitBlameFlag._(32, 'useMailmap');
+
+  /// Ignore whitespace differences.
+  static const ignoreWhitespace = GitBlameFlag._(64, 'ignoreWhitespace');
+
+  static const List<GitBlameFlag> values = [
+    normal,
+    trackCopiesSameFile,
+    trackCopiesSameCommitMoves,
+    trackCopiesSameCommitCopies,
+    trackCopiesAnyCommitCopies,
+    firstParent,
+    useMailmap,
+    ignoreWhitespace,
+  ];
+
+  int get value => _value;
+
+  @override
+  String toString() => 'GitBlameFlag.$_name';
+}

lib/src/remote.dart

@@ -1,15 +1,14 @@
 import 'dart:ffi';
-import 'package:libgit2dart/libgit2dart.dart';
-
 import 'bindings/libgit2_bindings.dart';
 import 'bindings/remote.dart' as bindings;
+import 'callbacks.dart';
 import 'git_types.dart';
 import 'refspec.dart';
 import 'repository.dart';
 
 class Remotes {
-  /// Initializes a new instance of the [References] class
-  /// from provided [Repository] object.
+  /// Initializes a new instance of the [Remotes] class from
+  /// provided [Repository] object.
   Remotes(Repository repo) {
     _repoPointer = repo.pointer;
   }

lib/src/repository.dart

@@ -1075,4 +1075,47 @@ class Repository {
       name: name,
     );
   }
+
+  /// Gets the blame for a single file.
+  ///
+  /// [flags] is a combination of [GitBlameFlag]s.
+  ///
+  /// [minMatchCharacters] is the lower bound on the number of alphanumeric
+  /// characters that must be detected as moving/copying within a file for
+  /// it to associate those lines with the parent commit. The default value is 20.
+  /// This value only takes effect if any of the [GitBlameFlag.trackCopies*]
+  /// flags are specified.
+  ///
+  /// [newestCommit] is the id of the newest commit to consider. The default is HEAD.
+  ///
+  /// [oldestCommit] is the id of the oldest commit to consider. The default is the
+  /// first commit encountered with no parent.
+  ///
+  /// [minLine] is the first line in the file to blame. The default is 1
+  /// (line numbers start with 1).
+  ///
+  /// [maxLine] is the last line in the file to blame. The default is the last
+  /// line of the file.
+  ///
+  /// Throws a [LibGit2Error] if error occured.
+  Blame blame({
+    required String path,
+    Set<GitBlameFlag> flags = const {GitBlameFlag.normal},
+    int? minMatchCharacters,
+    Oid? newestCommit,
+    Oid? oldestCommit,
+    int? minLine,
+    int? maxLine,
+  }) {
+    return Blame.file(
+      repo: this,
+      path: path,
+      flags: flags,
+      minMatchCharacters: minMatchCharacters,
+      newestCommit: newestCommit,
+      oldestCommit: oldestCommit,
+      minLine: minLine,
+      maxLine: maxLine,
+    );
+  }
 }

lib/src/signature.dart

@@ -80,4 +80,9 @@ class Signature {
 
   /// Releases memory allocated for signature object.
   void free() => bindings.free(_signaturePointer);
+
+  @override
+  String toString() {
+    return 'Signature{name: $name, email: $email, time: $time, offset: $offset}';
+  }
 }