Support delayed allocations from persistent memory.

base/metrics/persistent_memory_allocator_unittest.cc

 // Copyright 2015 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/metrics/persistent_memory_allocator.h"
 
 #include <memory>
 
 #include "base/files/file.h"
 #include "base/files/file_util.h"
@@ skipping 454 matching lines @@
   // simply by chance but it is useful during development to ensure that the
   // test is working correctly.
   EXPECT_NE(iterable_count, t1.count());
   EXPECT_NE(iterable_count, t2.count());
   EXPECT_NE(iterable_count, t3.count());
   EXPECT_NE(iterable_count, t4.count());
   EXPECT_NE(iterable_count, t5.count());
 #endif
 }
 
+TEST_F(PersistentMemoryAllocatorTest, DelayedAllocationTest) {
+  std::atomic<Reference> ref1, ref2;
+  ref1.store(0, std::memory_order_relaxed);
+  ref2.store(0, std::memory_order_relaxed);
+  DelayedPersistentAllocation da1(allocator_.get(), &ref1, 1001, 100);
+  DelayedPersistentAllocation da2a(allocator_.get(), &ref2, 2002, 200, 0);
+  DelayedPersistentAllocation da2b(allocator_.get(), &ref2, 2002, 200, 10);
+  da1.MakeIterable();
+  da2a.MakeIterable();
+  da2b.MakeIterable();
+
+  // Nothing should yet have been allocated.
+  uint32_t type;
+  PersistentMemoryAllocator::Iterator iter(allocator_.get());
+  EXPECT_EQ(0U, iter.GetNext(&type));
+
+  // Do first delayed allocation and check that a new persistent object exists.
+  EXPECT_EQ(0U, da1.reference());
+  void* mem1 = da1.Get();
+  ASSERT_TRUE(mem1);
+  EXPECT_NE(0U, da1.reference());
+  EXPECT_EQ(allocator_->GetAsReference(mem1, 1001),
+            ref1.load(std::memory_order_relaxed));
+  EXPECT_NE(0U, iter.GetNext(&type));
+  EXPECT_EQ(1001U, type);
+  EXPECT_EQ(0U, iter.GetNext(&type));
+
+  // Do second delayed allocation and check.
+  void* mem2a = da2a.Get();
+  ASSERT_TRUE(mem2a);
+  EXPECT_EQ(allocator_->GetAsReference(mem2a, 2002),
+            ref2.load(std::memory_order_relaxed));
+  EXPECT_NE(0U, iter.GetNext(&type));
+  EXPECT_EQ(2002U, type);
+  EXPECT_EQ(0U, iter.GetNext(&type));
+
+  // Third allocation should just return offset into second allocation.
+  void* mem2b = da2b.Get();
+  ASSERT_TRUE(mem2b);
+  EXPECT_EQ(0U, iter.GetNext(&type));
+  EXPECT_EQ(reinterpret_cast<uintptr_t>(mem2a) + 10,
+            reinterpret_cast<uintptr_t>(mem2b));
+}
+
 // This test doesn't verify anything other than it doesn't crash. Its goal
 // is to find coding errors that aren't otherwise tested for, much like a
 // "fuzzer" would.
 // This test is suppsoed to fail on TSAN bot (crbug.com/579867).
 #if defined(THREAD_SANITIZER)
 #define MAYBE_CorruptionTest DISABLED_CorruptionTest
 #else
 #define MAYBE_CorruptionTest CorruptionTest
 #endif
 TEST_F(PersistentMemoryAllocatorTest, MAYBE_CorruptionTest) {
@@ skipping 384 matching lines @@
       // For filesize >= minsize, the file must be acceptable. This
       // else clause (file-not-acceptable) should be reached only if
       // filesize < minsize.
       EXPECT_GT(minsize, filesize);
     }
   }
 }
 #endif  // !defined(OS_NACL)
 
 }  // namespace base