1 files changed, 116 insertions, 0 deletions
diff --git a/third_party/abseil-cpp/absl/strings/internal/cord_internal_test.cc b/third_party/abseil-cpp/absl/strings/internal/cord_internal_test.cc
new file mode 100644
index 0000000000..0758dfef38
--- /dev/null
+++ b/third_party/abseil-cpp/absl/strings/internal/cord_internal_test.cc
@@ -0,0 +1,116 @@
+// Copyright 2021 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/strings/internal/cord_internal.h"
+
+#include "gmock/gmock.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace cord_internal {
+
+TEST(RefcountAndFlags, NormalRefcount) {
+  for (bool expect_high_refcount : {false, true}) {
+    SCOPED_TRACE(expect_high_refcount);
+    RefcountAndFlags refcount;
+    // count = 1
+
+    EXPECT_FALSE(refcount.HasCrc());
+    EXPECT_TRUE(refcount.IsMutable());
+    EXPECT_TRUE(refcount.IsOne());
+
+    refcount.Increment();
+    // count = 2
+
+    EXPECT_FALSE(refcount.HasCrc());
+    EXPECT_FALSE(refcount.IsMutable());
+    EXPECT_FALSE(refcount.IsOne());
+
+    // Decrementing should return true, since a reference is outstanding.
+    if (expect_high_refcount) {
+      EXPECT_TRUE(refcount.DecrementExpectHighRefcount());
+    } else {
+      EXPECT_TRUE(refcount.Decrement());
+    }
+    // count = 1
+
+    EXPECT_FALSE(refcount.HasCrc());
+    EXPECT_TRUE(refcount.IsMutable());
+    EXPECT_TRUE(refcount.IsOne());
+
+    // One more decremnt will return false, as no references remain.
+    if (expect_high_refcount) {
+      EXPECT_FALSE(refcount.DecrementExpectHighRefcount());
+    } else {
+      EXPECT_FALSE(refcount.Decrement());
+    }
+  }
+}
+
+TEST(RefcountAndFlags, CrcRefcount) {
+  for (bool expect_high_refcount : {false, true}) {
+    SCOPED_TRACE(expect_high_refcount);
+    RefcountAndFlags refcount(RefcountAndFlags::WithCrc{});
+    // count = 1
+
+    // A CRC-carrying node is never mutable, but can be unshared
+    EXPECT_TRUE(refcount.HasCrc());
+    EXPECT_FALSE(refcount.IsMutable());
+    EXPECT_TRUE(refcount.IsOne());
+
+    refcount.Increment();
+    // count = 2
+
+    EXPECT_TRUE(refcount.HasCrc());
+    EXPECT_FALSE(refcount.IsMutable());
+    EXPECT_FALSE(refcount.IsOne());
+
+    // Decrementing should return true, since a reference is outstanding.
+    if (expect_high_refcount) {
+      EXPECT_TRUE(refcount.DecrementExpectHighRefcount());
+    } else {
+      EXPECT_TRUE(refcount.Decrement());
+    }
+    // count = 1
+
+    EXPECT_TRUE(refcount.HasCrc());
+    EXPECT_FALSE(refcount.IsMutable());
+    EXPECT_TRUE(refcount.IsOne());
+
+    // One more decremnt will return false, as no references remain.
+    if (expect_high_refcount) {
+      EXPECT_FALSE(refcount.DecrementExpectHighRefcount());
+    } else {
+      EXPECT_FALSE(refcount.Decrement());
+    }
+  }
+}
+
+TEST(RefcountAndFlags, ImmortalRefcount) {
+  RefcountAndFlags immortal_refcount(RefcountAndFlags::Immortal{});
+
+  for (int i = 0; i < 100; ++i) {
+    // An immortal refcount is never unshared, and decrementing never causes
+    // a collection.
+    EXPECT_FALSE(immortal_refcount.HasCrc());
+    EXPECT_FALSE(immortal_refcount.IsMutable());
+    EXPECT_FALSE(immortal_refcount.IsOne());
+    EXPECT_TRUE(immortal_refcount.Decrement());
+    EXPECT_TRUE(immortal_refcount.DecrementExpectHighRefcount());
+  }
+}
+
+}  // namespace cord_internal
+ABSL_NAMESPACE_END
+}  // namespace absl