Add discardable memory emulation for non-android/mac platforms

base/memory/discardable_memory_provider_unittest.cc

Index: base/memory/discardable_memory_provider_unittest.cc
diff --git a/base/memory/discardable_memory_provider_unittest.cc b/base/memory/discardable_memory_provider_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8c1aee896887aa95ec78e9035fc975c9fab93a73
--- /dev/null
+++ b/base/memory/discardable_memory_provider_unittest.cc
@@ -0,0 +1,347 @@
+// Copyright 2013 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/memory/discardable_memory_provider.h"
+
+#include "base/bind.h"
+#include "base/memory/discardable_memory.h"
+#include "base/run_loop.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/threading/thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using base::internal::DiscardableMemoryProvider;
+
+namespace base {
+
+class DiscardableMemoryProviderTestBase {
+ public:
+  DiscardableMemoryProviderTestBase()
+      : message_loop_(MessageLoop::TYPE_IO),
+        provider_(new DiscardableMemoryProvider) {
+    // We set a provider here for two reasons:
+    //   1. It ensures that one test cannot affect the next, and
+    //   2. Since the provider listens for pressure notifications on the thread
+    //      it was created on, if we create it on the test thread, we can run
+    //      the test thread's message loop until idle when we want to process
+    //      one of these notifications.
+    DiscardableMemoryProvider::SetInstanceForTest(provider_.get());
+  }
+
+  virtual ~DiscardableMemoryProviderTestBase() {
+    DiscardableMemoryProvider::SetInstanceForTest(NULL);
+  }
+
+ protected:
+  bool IsRegistered(const DiscardableMemory* discardable) {
+    return DiscardableMemoryProvider::GetInstance()->IsRegisteredForTest(
+        discardable);
+  }
+
+  bool CanBePurged(const DiscardableMemory* discardable) {
+    return DiscardableMemoryProvider::GetInstance()->CanBePurgedForTest(
+        discardable);
+  }
+
+  size_t BytesAllocated() const {
+    return DiscardableMemoryProvider::GetInstance()->
+        GetBytesAllocatedForTest();
+  }
+
+  void* Memory(const DiscardableMemory* discardable) const {
+    return discardable->Memory();
+  }
+
+  void SetDiscardableMemoryLimit(size_t bytes) {
+    DiscardableMemoryProvider::GetInstance()->
+        SetDiscardableMemoryLimit(bytes);
+  }
+
+  void SetBytesToReclaimUnderModeratePressure(size_t bytes) {
+    DiscardableMemoryProvider::GetInstance()->
+        SetBytesToReclaimUnderModeratePressure(bytes);
+  }
+
+ private:
+  MessageLoop message_loop_;
+  scoped_ptr<DiscardableMemoryProvider> provider_;
+};
+
+class DiscardableMemoryProviderTest
+    : public DiscardableMemoryProviderTestBase,
+      public testing::Test {
+ public:
+  DiscardableMemoryProviderTest() {}
+};
+
+TEST_F(DiscardableMemoryProviderTest, CreateLockedMemory) {
+  size_t size = 1024;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_TRUE(IsRegistered(discardable.get()));
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+  EXPECT_EQ(1024u, BytesAllocated());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+}
+
+TEST_F(DiscardableMemoryProviderTest, CreateLockedMemoryZeroSize) {
+  size_t size = 0;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_FALSE(discardable);
+  EXPECT_FALSE(IsRegistered(discardable.get()));
+  EXPECT_EQ(0u, BytesAllocated());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterUnlock) {
+  size_t size = 1024;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_TRUE(IsRegistered(discardable.get()));
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+  EXPECT_EQ(1024u, BytesAllocated());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+
+  // Now unlock so we can lock later.
+  discardable->Unlock();
+  EXPECT_TRUE(CanBePurged(discardable.get()));
+
+  EXPECT_EQ(DISCARDABLE_MEMORY_SUCCESS, discardable->Lock());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterPurge) {
+  size_t size = 1024;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_TRUE(IsRegistered(discardable.get()));
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+  EXPECT_EQ(1024u, BytesAllocated());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+
+  // Now unlock so we can lock later.
+  discardable->Unlock();
+  EXPECT_TRUE(CanBePurged(discardable.get()));
+
+  // Force the system to purge.
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+
+  // Required because ObserverListThreadSafe notifies via PostTask.
+  RunLoop().RunUntilIdle();
+
+  EXPECT_EQ(DISCARDABLE_MEMORY_PURGED, discardable->Lock());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterPurgeAndCannotReallocate) {
+  size_t size = 1024;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_TRUE(IsRegistered(discardable.get()));
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+  EXPECT_EQ(1024u, BytesAllocated());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+
+  // Now unlock so we can lock later.
+  discardable->Unlock();
+  EXPECT_TRUE(CanBePurged(discardable.get()));
+
+  // Set max allowed allocation to 1 byte. This will make cause the memory
+  // to be purged.
+  SetDiscardableMemoryLimit(1);
+
+  EXPECT_EQ(DISCARDABLE_MEMORY_PURGED, discardable->Lock());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+}
+
+class PermutationTestData {
+ public:
+  PermutationTestData(unsigned d0, unsigned d1, unsigned d2) {
+    ordering_[0] = d0;
+    ordering_[1] = d1;
+    ordering_[2] = d2;
+  }
+
+  const unsigned* ordering() const { return ordering_; }
+
+ private:
+  unsigned ordering_[3];
+};
+
+class DiscardableMemoryProviderPermutationTest
+    : public DiscardableMemoryProviderTestBase,
+      public testing::TestWithParam<PermutationTestData> {
+ public:
+  DiscardableMemoryProviderPermutationTest() {}
+
+ protected:
+  // Use discardable memory in order specified by ordering parameter.
+  void CreateAndUseDiscardableMemory() {
+    for (int i = 0; i < 3; ++i) {
+      discardables_[i] = DiscardableMemory::CreateLockedMemory(1024);
+      EXPECT_TRUE(discardables_[i]);
+      EXPECT_NE(static_cast<void*>(NULL), Memory(discardables_[i].get()));
+      discardables_[i]->Unlock();
+    }
+    for (int i = 0; i < 3; ++i) {
+      int index = GetParam().ordering()[i];
+      EXPECT_NE(DISCARDABLE_MEMORY_FAILED, discardables_[index]->Lock());
+      // Leave i == 0 locked.
+      if (i > 0)
+        discardables_[index]->Unlock();
+    }
+  }
+
+  DiscardableMemory* discardable(unsigned position) {
+    return discardables_[GetParam().ordering()[position]].get();
+  }
+
+ private:
+  scoped_ptr<DiscardableMemory> discardables_[3];
+};
+
+// Verify that memory was discarded in the correct order after applying
+// memory pressure.
+TEST_P(DiscardableMemoryProviderPermutationTest, LRUDiscardedModeratePressure) {
+  CreateAndUseDiscardableMemory();
+
+  SetBytesToReclaimUnderModeratePressure(1024);
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_MODERATE);
+  RunLoop().RunUntilIdle();
+
+  EXPECT_NE(DISCARDABLE_MEMORY_FAILED, discardable(2)->Lock());
+  EXPECT_NE(DISCARDABLE_MEMORY_SUCCESS, discardable(1)->Lock());
+  // 0 should still be locked.
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable(0)));
+}
+
+// Verify that memory was discarded in the correct order after changing
+// memory limit.
+TEST_P(DiscardableMemoryProviderPermutationTest, LRUDiscardedExceedLimit) {
+  CreateAndUseDiscardableMemory();
+
+  SetBytesToReclaimUnderModeratePressure(1024);
+  SetDiscardableMemoryLimit(2048);
+
+  EXPECT_NE(DISCARDABLE_MEMORY_FAILED, discardable(2)->Lock());
+  EXPECT_NE(DISCARDABLE_MEMORY_SUCCESS, discardable(1)->Lock());
+  // 0 should still be locked.
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable(0)));
+}
+
+TEST_P(DiscardableMemoryProviderPermutationTest,
+       CriticalPressureFreesAllUnlocked) {
+  CreateAndUseDiscardableMemory();
+
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+  RunLoop().RunUntilIdle();
+
+  for (int i = 0; i < 3; ++i) {
+    if (i == 0)
+      EXPECT_NE(static_cast<void*>(NULL), Memory(discardable(i)));
+    else
+      EXPECT_EQ(DISCARDABLE_MEMORY_PURGED, discardable(i)->Lock());
+  }
+}
+
+INSTANTIATE_TEST_CASE_P(DiscardableMemoryProviderPermutationTests,
+                        DiscardableMemoryProviderPermutationTest,
+                        ::testing::Values(PermutationTestData(0, 1, 2),
+                                          PermutationTestData(0, 2, 1),
+                                          PermutationTestData(1, 0, 2),
+                                          PermutationTestData(1, 2, 0),
+                                          PermutationTestData(2, 0, 1),
+                                          PermutationTestData(2, 1, 0)));
+
+TEST_F(DiscardableMemoryProviderTest, NormalDestruction) {
+  {
+    size_t size = 1024;
+    const scoped_ptr<DiscardableMemory> discardable(
+        DiscardableMemory::CreateLockedMemory(size));
+    EXPECT_TRUE(IsRegistered(discardable.get()));
+    EXPECT_EQ(1024u, BytesAllocated());
+  }
+  EXPECT_EQ(0u, BytesAllocated());
+}
+
+TEST_F(DiscardableMemoryProviderTest, DestructionWhileLocked) {
+  {
+    size_t size = 1024;
+    const scoped_ptr<DiscardableMemory> discardable(
+        DiscardableMemory::CreateLockedMemory(size));
+    EXPECT_TRUE(IsRegistered(discardable.get()));
+    EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+    EXPECT_EQ(1024u, BytesAllocated());
+    EXPECT_FALSE(CanBePurged(discardable.get()));
+  }
+  // Should have ignored the "locked" status and freed the discardable memory.
+  EXPECT_EQ(0u, BytesAllocated());
+}
+
+#if !defined(NDEBUG) && !defined(OS_ANDROID)
+// Death tests are not supported with Android APKs.
+TEST_F(DiscardableMemoryProviderTest, UnlockedMemoryAccessCrashesInDebugMode) {
+  size_t size = 1024;
+  const scoped_ptr<DiscardableMemory> discardable(
+      DiscardableMemory::CreateLockedMemory(size));
+  EXPECT_TRUE(IsRegistered(discardable.get()));
+  EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+  EXPECT_EQ(1024u, BytesAllocated());
+  EXPECT_FALSE(CanBePurged(discardable.get()));
+  discardable->Unlock();
+  EXPECT_TRUE(CanBePurged(discardable.get()));
+  // We *must* die if we are asked to vend a pointer to unlocked memory.
+  EXPECT_DEATH(discardable->Memory(), ".*Check failed.*");
+}
+#endif
+
+class ThreadedDiscardableMemoryProviderTest
+    : public DiscardableMemoryProviderTest {
+ public:
+  ThreadedDiscardableMemoryProviderTest()
+      : memory_usage_thread_("memory_usage_thread"),
+        thread_sync_(true, false) {
+  }
+
+  virtual void SetUp() OVERRIDE {
+    memory_usage_thread_.Start();
+  }
+
+  virtual void TearDown() OVERRIDE {
+    memory_usage_thread_.Stop();
+  }
+
+  void UseMemoryHelper() {
+    size_t size = 1024;
+    const scoped_ptr<DiscardableMemory> discardable(
+        DiscardableMemory::CreateLockedMemory(size));
+    EXPECT_TRUE(IsRegistered(discardable.get()));
+    EXPECT_NE(static_cast<void*>(NULL), Memory(discardable.get()));
+    discardable->Unlock();
+  }
+
+  void SignalHelper() {
+    thread_sync_.Signal();
+  }
+
+  Thread memory_usage_thread_;
+  WaitableEvent thread_sync_;
+};
+
+TEST_F(ThreadedDiscardableMemoryProviderTest, UseMemoryOnThread) {
+  memory_usage_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      Bind(&ThreadedDiscardableMemoryProviderTest::UseMemoryHelper,
+           Unretained(this)));
+  memory_usage_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      Bind(&ThreadedDiscardableMemoryProviderTest::SignalHelper,
+           Unretained(this)));
+  thread_sync_.Wait();
+}
+
+}  // namespace base