From c3896fa84d54e44dc1910d6f202a47d3640b6fa5 Mon Sep 17 00:00:00 2001
From: Juanli Shen <juanlishen@google.com>
Date: Thu, 25 Jul 2019 10:37:22 -0700
Subject: [PATCH] Make Map<> movable

---
 src/core/lib/gprpp/map.h    | 17 +++++++++++++++++
 test/core/gprpp/map_test.cc | 29 +++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/core/lib/gprpp/map.h b/src/core/lib/gprpp/map.h
index 36e32d60c07..2babe35cd1b 100644
--- a/src/core/lib/gprpp/map.h
+++ b/src/core/lib/gprpp/map.h
@@ -55,8 +55,25 @@ class Map {
   typedef Compare key_compare;
   class iterator;
 
+  Map() = default;
   ~Map() { clear(); }
 
+  // Movable.
+  Map(Map&& other) : root_(other.root_), size_(other.size_) {
+    other.root_ = nullptr;
+    other.size_ = 0;
+  }
+  Map& operator=(Map&& other) {
+    if (this != &other) {
+      clear();
+      root_ = other.root_;
+      size_ = other.size_;
+      other.root_ = nullptr;
+      other.size_ = 0;
+    }
+    return *this;
+  }
+
   T& operator[](key_type&& key);
   T& operator[](const key_type& key);
   iterator find(const key_type& k);
diff --git a/test/core/gprpp/map_test.cc b/test/core/gprpp/map_test.cc
index 30d9eb0b207..21aeee82486 100644
--- a/test/core/gprpp/map_test.cc
+++ b/test/core/gprpp/map_test.cc
@@ -437,6 +437,35 @@ TEST_F(MapTest, LowerBound) {
   EXPECT_EQ(it, test_map.end());
 }
 
+// Test move ctor
+TEST_F(MapTest, MoveCtor) {
+  Map<const char*, Payload, StringLess> test_map;
+  for (int i = 0; i < 5; i++) {
+    test_map.emplace(kKeys[i], Payload(i));
+  }
+  Map<const char*, Payload, StringLess> test_map2 = std::move(test_map);
+  for (int i = 0; i < 5; i++) {
+    EXPECT_EQ(test_map.end(), test_map.find(kKeys[i]));
+    EXPECT_EQ(i, test_map2.find(kKeys[i])->second.data());
+  }
+}
+
+// Test move assignment
+TEST_F(MapTest, MoveAssignment) {
+  Map<const char*, Payload, StringLess> test_map;
+  for (int i = 0; i < 5; i++) {
+    test_map.emplace(kKeys[i], Payload(i));
+  }
+  Map<const char*, Payload, StringLess> test_map2;
+  test_map2.emplace("xxx", Payload(123));
+  test_map2 = std::move(test_map);
+  for (int i = 0; i < 5; i++) {
+    EXPECT_EQ(test_map.end(), test_map.find(kKeys[i]));
+    EXPECT_EQ(i, test_map2.find(kKeys[i])->second.data());
+  }
+  EXPECT_EQ(test_map2.end(), test_map2.find("xxx"));
+}
+
 }  // namespace testing
 }  // namespace grpc_core