From 75049771c300f00c3bd546ee314fbbc47972e8cf Mon Sep 17 00:00:00 2001
From: Omer Katz <omerkatz@chromium.org>
Date: Tue, 20 Oct 2020 23:15:05 +0200
Subject: [PATCH] cppgc, heap: Add Clear and IsEmpty methods to Worklist::Local

Bug: v8:10990
Change-Id: I5166d9ecd6d8d8c55ecb17015d99d88ed60effa2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2488680
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70668}
---
 src/heap/base/worklist.h                      | 14 ++++++++
 test/unittests/heap/base/worklist-unittest.cc | 34 ++++++++++++++++---
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/src/heap/base/worklist.h b/src/heap/base/worklist.h
index be2ecf158b..e2d33616ad 100644
--- a/src/heap/base/worklist.h
+++ b/src/heap/base/worklist.h
@@ -285,6 +285,9 @@ class Worklist<EntryType, SegmentSize>::Local {
   void Publish();
   void Merge(Worklist<EntryType, SegmentSize>::Local* other);
 
+  bool IsEmpty() const;
+  void Clear();
+
   size_t PushSegmentSize() const { return push_segment_->Size(); }
 
  private:
@@ -445,6 +448,17 @@ bool Worklist<EntryType, SegmentSize>::Local::StealPopSegment() {
   return false;
 }
 
+template <typename EntryType, uint16_t SegmentSize>
+bool Worklist<EntryType, SegmentSize>::Local::IsEmpty() const {
+  return push_segment_->IsEmpty() && pop_segment_->IsEmpty();
+}
+
+template <typename EntryType, uint16_t SegmentSize>
+void Worklist<EntryType, SegmentSize>::Local::Clear() {
+  push_segment_->Clear();
+  pop_segment_->Clear();
+}
+
 }  // namespace base
 }  // namespace heap
 
diff --git a/test/unittests/heap/base/worklist-unittest.cc b/test/unittests/heap/base/worklist-unittest.cc
index ae737a7aa3..fe9be18ecd 100644
--- a/test/unittests/heap/base/worklist-unittest.cc
+++ b/test/unittests/heap/base/worklist-unittest.cc
@@ -110,21 +110,45 @@ TEST(CppgcWorkListTest, LocalPushPop) {
 
 TEST(CppgcWorkListTest, LocalPushStaysPrivate) {
   TestWorklist worklist;
-  TestWorklist::Local worklist_view1(&worklist);
-  TestWorklist::Local worklist_view2(&worklist);
+  TestWorklist::Local worklist_local1(&worklist);
+  TestWorklist::Local worklist_local2(&worklist);
   SomeObject dummy;
   SomeObject* retrieved = nullptr;
   EXPECT_TRUE(worklist.IsEmpty());
   EXPECT_EQ(0U, worklist.Size());
-  worklist_view1.Push(&dummy);
+  worklist_local1.Push(&dummy);
   EXPECT_EQ(0U, worklist.Size());
-  EXPECT_FALSE(worklist_view2.Pop(&retrieved));
+  EXPECT_FALSE(worklist_local2.Pop(&retrieved));
   EXPECT_EQ(nullptr, retrieved);
-  EXPECT_TRUE(worklist_view1.Pop(&retrieved));
+  EXPECT_TRUE(worklist_local1.Pop(&retrieved));
   EXPECT_EQ(&dummy, retrieved);
   EXPECT_EQ(0U, worklist.Size());
 }
 
+TEST(CppgcWorkListTest, LocalClear) {
+  TestWorklist worklist;
+  TestWorklist::Local worklist_local(&worklist);
+  SomeObject* object;
+  object = reinterpret_cast<SomeObject*>(&object);
+  // Check push segment:
+  EXPECT_TRUE(worklist_local.IsEmpty());
+  worklist_local.Push(object);
+  EXPECT_FALSE(worklist_local.IsEmpty());
+  worklist_local.Clear();
+  EXPECT_TRUE(worklist_local.IsEmpty());
+  // Check pop segment:
+  worklist_local.Push(object);
+  worklist_local.Push(object);
+  EXPECT_FALSE(worklist_local.IsEmpty());
+  worklist_local.Publish();
+  EXPECT_TRUE(worklist_local.IsEmpty());
+  SomeObject* retrieved;
+  worklist_local.Pop(&retrieved);
+  EXPECT_FALSE(worklist_local.IsEmpty());
+  worklist_local.Clear();
+  EXPECT_TRUE(worklist_local.IsEmpty());
+}
+
 TEST(CppgcWorkListTest, GlobalUpdateNull) {
   TestWorklist worklist;
   TestWorklist::Local worklist_local(&worklist);