From 48e2240c73252078247b1f0fa5f7bf19875112c6 Mon Sep 17 00:00:00 2001
From: Aleksey Kulikov <skinny.mind@gmail.com>
Date: Thu, 9 Jun 2022 17:15:55 +0300
Subject: [PATCH] feat(revwalk): add ability to limit number of commits to walk
 (#65)

---
 lib/src/bindings/revwalk.dart | 18 +++++++++++++++---
 lib/src/revwalk.dart          |  6 +++++-
 test/revwalk_test.dart        | 10 ++++++++++
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/lib/src/bindings/revwalk.dart b/lib/src/bindings/revwalk.dart
index 93d9bf6..1869067 100644
--- a/lib/src/bindings/revwalk.dart
+++ b/lib/src/bindings/revwalk.dart
@@ -145,11 +145,12 @@ void pushRange({
 List<Pointer<git_commit>> walk({
   required Pointer<git_repository> repoPointer,
   required Pointer<git_revwalk> walkerPointer,
+  required int limit,
 }) {
   final result = <Pointer<git_commit>>[];
   var error = 0;
 
-  while (error == 0) {
+  void next() {
     final oid = calloc<git_oid>();
     error = libgit2.git_revwalk_next(oid, walkerPointer);
     if (error == 0) {
@@ -158,10 +159,21 @@ List<Pointer<git_commit>> walk({
         oidPointer: oid,
       );
       result.add(commit);
+      calloc.free(oid);
     } else {
-      break;
+      calloc.free(oid);
+      return;
+    }
+  }
+
+  if (limit == 0) {
+    while (error == 0) {
+      next();
+    }
+  } else {
+    for (var i = 0; i < limit; i++) {
+      next();
     }
-    calloc.free(oid);
   }
 
   return result;
diff --git a/lib/src/revwalk.dart b/lib/src/revwalk.dart
index c3a08c7..610ebb9 100644
--- a/lib/src/revwalk.dart
+++ b/lib/src/revwalk.dart
@@ -19,11 +19,15 @@ class RevWalk {
 
   /// Returns the list of commits from the revision walk.
   ///
+  /// [limit] is optional number of commits to walk (by default walks through
+  /// all of the commits pushed onto the walker).
+  ///
   /// Default sorting is reverse chronological order (default in git).
-  List<Commit> walk() {
+  List<Commit> walk({int limit = 0}) {
     final pointers = bindings.walk(
       repoPointer: bindings.repository(_revWalkPointer),
       walkerPointer: _revWalkPointer,
+      limit: limit,
     );
 
     return pointers.map((e) => Commit(e)).toList();
diff --git a/test/revwalk_test.dart b/test/revwalk_test.dart
index e491ab0..5b3c9a0 100644
--- a/test/revwalk_test.dart
+++ b/test/revwalk_test.dart
@@ -50,6 +50,16 @@ void main() {
       }
     });
 
+    test('walks only number of commits provided with limit', () {
+      final walker = RevWalk(repo);
+
+      walker.push(repo[log.first]);
+      final commits = walker.walk(limit: 1);
+
+      expect(commits.length, 1);
+      expect(commits[0].oid.sha, log[0]);
+    });
+
     test('returns list of commits with reverse sorting', () {
       final walker = RevWalk(repo);