Update from chromium https://crrev.com/301315

base/memory/discardable_shared_memory_unittest.cc

Index: base/memory/discardable_shared_memory_unittest.cc
diff --git a/base/memory/discardable_shared_memory_unittest.cc b/base/memory/discardable_shared_memory_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e5174298bfd8a7f74920b00dbdb650fde9aef086
--- /dev/null
+++ b/base/memory/discardable_shared_memory_unittest.cc
@@ -0,0 +1,251 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/basictypes.h"
+#include "base/memory/discardable_shared_memory.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+class TestDiscardableSharedMemory : public DiscardableSharedMemory {
+ public:
+  TestDiscardableSharedMemory() {}
+
+  explicit TestDiscardableSharedMemory(SharedMemoryHandle handle)
+      : DiscardableSharedMemory(handle) {}
+
+  void SetNow(Time now) { now_ = now; }
+
+ private:
+  // Overriden from DiscardableSharedMemory:
+  virtual Time Now() const override { return now_; }
+
+  Time now_;
+};
+
+TEST(DiscardableSharedMemoryTest, CreateAndMap) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory;
+  bool rv = memory.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+  EXPECT_GE(memory.mapped_size(), kDataSize);
+}
+
+TEST(DiscardableSharedMemoryTest, CreateFromHandle) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory1;
+  bool rv = memory1.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+
+  SharedMemoryHandle shared_handle;
+  ASSERT_TRUE(
+      memory1.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
+  ASSERT_TRUE(SharedMemory::IsHandleValid(shared_handle));
+
+  TestDiscardableSharedMemory memory2(shared_handle);
+  rv = memory2.Map(kDataSize);
+  ASSERT_TRUE(rv);
+}
+
+TEST(DiscardableSharedMemoryTest, LockAndUnlock) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory1;
+  bool rv = memory1.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+
+  // Memory is initially locked. Unlock it.
+  memory1.SetNow(Time::FromDoubleT(1));
+  memory1.Unlock();
+
+  // Lock and unlock memory.
+  rv = memory1.Lock();
+  EXPECT_TRUE(rv);
+  memory1.SetNow(Time::FromDoubleT(2));
+  memory1.Unlock();
+
+  SharedMemoryHandle shared_handle;
+  ASSERT_TRUE(
+      memory1.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
+  ASSERT_TRUE(SharedMemory::IsHandleValid(shared_handle));
+
+  TestDiscardableSharedMemory memory2(shared_handle);
+  rv = memory2.Map(kDataSize);
+  ASSERT_TRUE(rv);
+
+  // Lock first instance again.
+  rv = memory1.Lock();
+  EXPECT_TRUE(rv);
+
+  // Unlock second instance.
+  memory2.SetNow(Time::FromDoubleT(3));
+  memory2.Unlock();
+
+  // Lock and unlock second instance.
+  rv = memory2.Lock();
+  EXPECT_TRUE(rv);
+  memory2.SetNow(Time::FromDoubleT(4));
+  memory2.Unlock();
+
+  // Try to lock first instance again. Should fail as first instance has an
+  // incorrect last know usage time.
+  rv = memory1.Lock();
+  EXPECT_FALSE(rv);
+
+  // Memory should still be resident.
+  rv = memory1.IsMemoryResident();
+  EXPECT_TRUE(rv);
+
+  // Second attempt to lock first instance should succeed as last known usage
+  // time is now correct.
+  rv = memory1.Lock();
+  EXPECT_TRUE(rv);
+  memory1.SetNow(Time::FromDoubleT(5));
+  memory1.Unlock();
+}
+
+TEST(DiscardableSharedMemoryTest, Purge) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory1;
+  bool rv = memory1.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+
+  SharedMemoryHandle shared_handle;
+  ASSERT_TRUE(
+      memory1.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
+  ASSERT_TRUE(SharedMemory::IsHandleValid(shared_handle));
+
+  TestDiscardableSharedMemory memory2(shared_handle);
+  rv = memory2.Map(kDataSize);
+  ASSERT_TRUE(rv);
+
+  // This should fail as memory is locked.
+  rv = memory1.Purge(Time::FromDoubleT(1));
+  EXPECT_FALSE(rv);
+
+  memory2.SetNow(Time::FromDoubleT(2));
+  memory2.Unlock();
+
+  ASSERT_TRUE(memory2.IsMemoryResident());
+
+  // Memory is unlocked, but our usage timestamp is incorrect.
+  rv = memory1.Purge(Time::FromDoubleT(3));
+  EXPECT_FALSE(rv);
+
+  ASSERT_TRUE(memory2.IsMemoryResident());
+
+  // Memory is unlocked and our usage timestamp should be correct.
+  rv = memory1.Purge(Time::FromDoubleT(4));
+  EXPECT_TRUE(rv);
+
+  // Lock should fail as memory has been purged.
+  rv = memory2.Lock();
+  EXPECT_FALSE(rv);
+
+  ASSERT_FALSE(memory2.IsMemoryResident());
+}
+
+TEST(DiscardableSharedMemoryTest, LastUsed) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory1;
+  bool rv = memory1.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+
+  SharedMemoryHandle shared_handle;
+  ASSERT_TRUE(
+      memory1.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
+  ASSERT_TRUE(SharedMemory::IsHandleValid(shared_handle));
+
+  TestDiscardableSharedMemory memory2(shared_handle);
+  rv = memory2.Map(kDataSize);
+  ASSERT_TRUE(rv);
+
+  memory2.SetNow(Time::FromDoubleT(1));
+  memory2.Unlock();
+
+  EXPECT_EQ(memory2.last_known_usage(), Time::FromDoubleT(1));
+
+  rv = memory2.Lock();
+  EXPECT_TRUE(rv);
+
+  // This should fail as memory is locked.
+  rv = memory1.Purge(Time::FromDoubleT(2));
+  ASSERT_FALSE(rv);
+
+  // Last usage should have been updated to timestamp passed to Purge above.
+  EXPECT_EQ(memory1.last_known_usage(), Time::FromDoubleT(2));
+
+  memory2.SetNow(Time::FromDoubleT(3));
+  memory2.Unlock();
+
+  // Usage time should be correct for |memory2| instance.
+  EXPECT_EQ(memory2.last_known_usage(), Time::FromDoubleT(3));
+
+  // However, usage time has not changed as far as |memory1| instance knows.
+  EXPECT_EQ(memory1.last_known_usage(), Time::FromDoubleT(2));
+
+  // Memory is unlocked, but our usage timestamp is incorrect.
+  rv = memory1.Purge(Time::FromDoubleT(4));
+  EXPECT_FALSE(rv);
+
+  // The failed purge attempt should have updated usage time to the correct
+  // value.
+  EXPECT_EQ(memory1.last_known_usage(), Time::FromDoubleT(3));
+
+  // Purge memory through |memory2| instance. The last usage time should be
+  // set to 0 as a result of this.
+  rv = memory2.Purge(Time::FromDoubleT(5));
+  EXPECT_TRUE(rv);
+  EXPECT_TRUE(memory2.last_known_usage().is_null());
+
+  // This should fail as memory has already been purged and |memory1|'s usage
+  // time is incorrect as a result.
+  rv = memory1.Purge(Time::FromDoubleT(6));
+  EXPECT_FALSE(rv);
+
+  // The failed purge attempt should have updated usage time to the correct
+  // value.
+  EXPECT_TRUE(memory1.last_known_usage().is_null());
+
+  // Purge should succeed now that usage time is correct.
+  rv = memory1.Purge(Time::FromDoubleT(7));
+  EXPECT_TRUE(rv);
+}
+
+TEST(DiscardableSharedMemoryTest, LockShouldAlwaysFailAfterSuccessfulPurge) {
+  const uint32 kDataSize = 1024;
+
+  TestDiscardableSharedMemory memory1;
+  bool rv = memory1.CreateAndMap(kDataSize);
+  ASSERT_TRUE(rv);
+
+  SharedMemoryHandle shared_handle;
+  ASSERT_TRUE(
+      memory1.ShareToProcess(GetCurrentProcessHandle(), &shared_handle));
+  ASSERT_TRUE(SharedMemory::IsHandleValid(shared_handle));
+
+  TestDiscardableSharedMemory memory2(shared_handle);
+  rv = memory2.Map(kDataSize);
+  ASSERT_TRUE(rv);
+
+  memory2.SetNow(Time::FromDoubleT(1));
+  memory2.Unlock();
+
+  rv = memory2.Purge(Time::FromDoubleT(2));
+  EXPECT_TRUE(rv);
+
+  // Lock should fail as memory has been purged.
+  rv = memory2.Lock();
+  EXPECT_FALSE(rv);
+  rv = memory1.Lock();
+  EXPECT_FALSE(rv);
+}
+
+}  // namespace
+}  // namespace base