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..6e3dab695ea44f5fae4abc66c801ccd354a3dfe0
--- /dev/null
+++ b/base/memory/discardable_memory_provider_unittest.cc
@@ -0,0 +1,282 @@
+// Copyright (c) 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/memory/discardable_memory.h"
+#include "base/message_loop.h"
+#include "base/run_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+class DiscardableMemoryProviderTest : public testing::Test {
+ public:
+  DiscardableMemoryProviderTest()
+      : message_loop_(MessageLoop::TYPE_IO),
+        provider_(new DiscardableMemoryProvider) {
+    DiscardableMemoryProvider::SetInstanceForTest(provider_.get());

[Avi (use Gerrit), 2013/06/18 00:00:46]

I'm lost; why are we keeping our own provider here and setting it as the
instance?

+  }
+
+  virtual ~DiscardableMemoryProviderTest() {
+    DiscardableMemoryProvider::SetInstanceForTest(NULL);
+  }
+
+ protected:
+  void Register(DiscardableMemory* discardable) {
+    DiscardableMemoryProvider::GetInstance()->Register(discardable);
+  }
+
+  const DiscardableMemoryProvider::AllocationMap& allocations() const {
+    return DiscardableMemoryProvider::GetInstance()->allocations_;
+  }
+
+  size_t bytes_allocated() const {
+    return DiscardableMemoryProvider::GetInstance()->bytes_allocated_;
+  }
+
+  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_;
+};
+
+TEST_F(DiscardableMemoryProviderTest, Register) {
+  DiscardableMemory discardable;
+  Register(&discardable);
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_EQ(0u, bytes_allocated());
+}
+
+TEST_F(DiscardableMemoryProviderTest, InitializeAndLock) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 1024;
+  ASSERT_TRUE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(1024u, bytes_allocated());
+  ASSERT_TRUE(discardable.is_locked());
+}
+
+TEST_F(DiscardableMemoryProviderTest, InitializeAndLockZeroSize) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 0;
+  ASSERT_FALSE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(0u, bytes_allocated());
+  ASSERT_FALSE(discardable.is_locked());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockBeforeInitialization) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(DISCARDABLE_MEMORY_FAILED, discardable.Lock());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterUnlock) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 1024;
+  ASSERT_TRUE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(1024u, bytes_allocated());
+  ASSERT_TRUE(discardable.is_locked());
+
+  // Now to unlock so we can lock later.
+  discardable.Unlock();
+  ASSERT_FALSE(discardable.is_locked());
+
+  ASSERT_EQ(DISCARDABLE_MEMORY_SUCCESS, discardable.Lock());
+  ASSERT_TRUE(discardable.is_locked());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterPurge) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 1024;
+  ASSERT_TRUE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(1024u, bytes_allocated());
+  ASSERT_TRUE(discardable.is_locked());
+
+  // Now to unlock so we can lock later.
+  discardable.Unlock();
+  ASSERT_FALSE(discardable.is_locked());
+
+  // Force the system to purge.
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+
+  // Required because ObserverListThreadSafe notifies via PostTask.
+  RunLoop().RunUntilIdle();
+
+  ASSERT_EQ(DISCARDABLE_MEMORY_PURGED, discardable.Lock());
+  ASSERT_TRUE(discardable.is_locked());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockAfterPurgeAndCannotReallocate) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 1024;
+  ASSERT_TRUE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(1024u, bytes_allocated());
+  ASSERT_TRUE(discardable.is_locked());
+
+  // Now to unlock so we can lock later.
+  discardable.Unlock();
+  ASSERT_FALSE(discardable.is_locked());
+
+  // Force the system to purge.
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+
+  // Required because ObserverListThreadSafe notifies via PostTask.
+  RunLoop().RunUntilIdle();
+
+  // Set max allowed allocation to 1 byte. This will make reallocation fail.
+  SetDiscardableMemoryLimit(1);
+
+  ASSERT_EQ(DISCARDABLE_MEMORY_FAILED, discardable.Lock());
+  ASSERT_FALSE(discardable.is_locked());
+}
+
+#define DiscardableMemoryProviderPermutionTest(name, d0, d1, d2, pressure)    \
+TEST_F(DiscardableMemoryProviderTest, name##_##d0##_##d1##_##d2) {            \
+  DiscardableMemory discardables[3];                                          \
+  for (int i = 0; i < 3; ++i) {                                               \
+    ASSERT_EQ(static_cast<void*>(NULL), Memory(discardables[i]));             \
+    ASSERT_TRUE(discardables[i].InitializeAndLock(1024));                     \
+    discardables[i].Unlock();                                                 \
+    ASSERT_NE(static_cast<void*>(NULL), Memory(discardables[i]));             \
+  }                                                                           \
+  int ordering[] = { d0, d1, d2 };                                            \
+  for (int i = 0; i < 3; ++i) {                                               \
+    int current_index = ordering[i];                                          \
+    ASSERT_NE(DISCARDABLE_MEMORY_FAILED, discardables[current_index].Lock()); \
+    if (i > 0)                                                                \
+      discardables[current_index].Unlock();                                   \
+  }                                                                           \
+  SetBytesToReclaimUnderModeratePressure(1024);                               \
+  if (pressure) {                                                             \
+    MemoryPressureListener::NotifyMemoryPressure(                             \
+        MemoryPressureListener::MEMORY_PRESSURE_MODERATE);                    \
+    RunLoop().RunUntilIdle();                                                 \
+  } else {                                                                    \
+    SetDiscardableMemoryLimit(2048);                                          \
+  }                                                                           \
+  for (int i = 0; i < 3; ++i) {                                               \
+    if (i == 1)                                                               \
+      ASSERT_EQ(static_cast<void*>(NULL), Memory(discardables[ordering[i]])); \
+    else                                                                      \
+      ASSERT_NE(static_cast<void*>(NULL), Memory(discardables[ordering[i]])); \
+  }                                                                           \
+}
+
+#define DiscardableMemoryProviderPermutions(name, pressure)      \
+DiscardableMemoryProviderPermutionTest(name, 0, 1, 2, pressure); \
+DiscardableMemoryProviderPermutionTest(name, 0, 2, 1, pressure); \
+DiscardableMemoryProviderPermutionTest(name, 1, 0, 2, pressure); \
+DiscardableMemoryProviderPermutionTest(name, 1, 2, 0, pressure); \
+DiscardableMemoryProviderPermutionTest(name, 2, 0, 1, pressure); \
+DiscardableMemoryProviderPermutionTest(name, 2, 1, 0, pressure);
+
+DiscardableMemoryProviderPermutions(LRUDiscardedModeratePressure, true);
+DiscardableMemoryProviderPermutions(LRUDiscardedExceedLimit, false);
+
+TEST_F(DiscardableMemoryProviderTest, CriticalPressureFreesAllUnlocked) {
+  DiscardableMemory discardables[3];
+  for (int i = 0; i < 3; ++i) {
+    ASSERT_EQ(static_cast<void*>(NULL), Memory(discardables[i]));
+    ASSERT_TRUE(discardables[i].InitializeAndLock(1024));
+    discardables[i].Unlock();
+    ASSERT_NE(static_cast<void*>(NULL), Memory(discardables[i]));
+  }
+
+  for (int i = 0; i < 3; ++i) {
+    ASSERT_NE(DISCARDABLE_MEMORY_FAILED, discardables[i].Lock());
+    if (i > 0)
+      discardables[i].Unlock();
+  }
+
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+  RunLoop().RunUntilIdle();
+
+  for (int i = 0; i < 3; ++i) {
+    if (discardables[i].is_locked())
+      ASSERT_NE(static_cast<void*>(NULL), Memory(discardables[i]));
+    else
+      ASSERT_EQ(static_cast<void*>(NULL), Memory(discardables[i]));
+  }
+}
+
+TEST_F(DiscardableMemoryProviderTest, NormalDestruction) {
+  {
+    DiscardableMemory discardable;
+    size_t size = 1024;
+    ASSERT_TRUE(discardable.InitializeAndLock(size));
+    ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+    ASSERT_EQ(1024u, bytes_allocated());
+  }
+  ASSERT_TRUE(allocations().empty());
+  ASSERT_EQ(0u, bytes_allocated());
+}
+
+TEST_F(DiscardableMemoryProviderTest, DestructionWhileLocked) {
+  {
+    DiscardableMemory discardable;
+    ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+    size_t size = 1024;
+    ASSERT_TRUE(discardable.InitializeAndLock(size));
+    ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+    ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+    ASSERT_EQ(1024u, bytes_allocated());
+    ASSERT_TRUE(discardable.is_locked());
+  }
+  // Should have ignored the "locked" status and freed the discardable memory.
+  ASSERT_TRUE(allocations().empty());
+  ASSERT_EQ(0u, bytes_allocated());
+}
+
+TEST_F(DiscardableMemoryProviderTest, MemoryBeforeLock) {
+  DiscardableMemory discardable;
+  // We *must* die if we are asked to vend a pointer to unlocked memory.
+  EXPECT_DEATH(discardable.Memory(), ".*Check failed.*");
+}
+
+TEST_F(DiscardableMemoryProviderTest, MemoryAfterUnlock) {
+  DiscardableMemory discardable;
+  ASSERT_EQ(static_cast<void*>(NULL), Memory(discardable));
+  size_t size = 1024;
+  ASSERT_TRUE(discardable.InitializeAndLock(size));
+  ASSERT_NE(allocations().end(), allocations().Peek(&discardable));
+  ASSERT_NE(static_cast<void*>(NULL), Memory(discardable));
+  ASSERT_EQ(1024u, bytes_allocated());
+  ASSERT_TRUE(discardable.is_locked());
+  discardable.Unlock();
+  ASSERT_FALSE(discardable.is_locked());
+  // We *must* die if we are asked to vend a pointer to unlocked memory.
+  EXPECT_DEATH(discardable.Memory(), ".*Check failed.*");
+}
+
+}  // namespace base