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..dd97155501b59e61b74bc9acd4b7decb26e3236e
--- /dev/null
+++ b/base/memory/discardable_memory_provider_unittest.cc
@@ -0,0 +1,294 @@
+// 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/memory/discardable_memory.h"
+#include "base/run_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using base::internal::DiscardableMemoryProvider;
+
+namespace base {
+
+class DiscardableMemoryProviderTest : public testing::Test {
+ public:
+  DiscardableMemoryProviderTest()
+      : 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
+    //      on of these notifications.
+    DiscardableMemoryProvider::SetInstanceForTest(provider_.get());
+  }
+
+  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));

[willchan no longer on Chromium, 2013/10/01 19:05:05]

You should use EXPECT_*() unless the following statements would crash otherwise,
or it would trigger way too many errors and not be useful. Since these are
checking the various accessors which are independent, it's good to EXPECT_* on
them separately.

[reveman, 2013/10/09 22:40:24]

Done.

+  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());
+}
+
+static void AttemptToLockBeforeInitialization(DiscardableMemory* discardable) {
+  ASSERT_EQ(DISCARDABLE_MEMORY_FAILED, discardable->Lock());
+}
+
+TEST_F(DiscardableMemoryProviderTest, LockBeforeInitialization) {
+  DiscardableMemory discardable;
+  EXPECT_DEATH(AttemptToLockBeforeInitialization(&discardable),
+               ".*Check failed.*");
+}
+
+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(

[willchan no longer on Chromium, 2013/10/01 19:05:05]

You should add a test with a DiscardableMemory on a different thread.

[reveman, 2013/10/09 22:40:24]

I added a basic test that uses a DiscardableMemory on a different thread.

+      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