Add support for turning pointers back to references.

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 103 matching lines @@
   EXPECT_NE(nullptr, allocator_->GetAsObject<TestObject1>(block1, 1));
   EXPECT_EQ(nullptr, allocator_->GetAsObject<TestObject2>(block1, 1));
   EXPECT_LE(sizeof(TestObject1), allocator_->GetAllocSize(block1));
   EXPECT_GT(sizeof(TestObject1) + kAllocAlignment,
             allocator_->GetAllocSize(block1));
   PersistentMemoryAllocator::MemoryInfo meminfo1;
   allocator_->GetMemoryInfo(&meminfo1);
   EXPECT_EQ(meminfo0.total, meminfo1.total);
   EXPECT_GT(meminfo0.free, meminfo1.free);
 
+  // Verify that pointers can be turned back into references and that invalid
+  // addresses return null.
+  char* memory1 = allocator_->GetAsArray<char>(block1, 1, 1);
+  ASSERT_TRUE(memory1);
+  EXPECT_EQ(block1, allocator_->GetAsReference(memory1, 0));
+  EXPECT_EQ(block1, allocator_->GetAsReference(memory1, 1));
+  EXPECT_EQ(0U, allocator_->GetAsReference(memory1, 2));
+  EXPECT_EQ(0U, allocator_->GetAsReference(memory1 + 1, 0));
+  EXPECT_EQ(0U, allocator_->GetAsReference(memory1 + 16, 0));
+  EXPECT_EQ(0U, allocator_->GetAsReference(nullptr, 0));
+  EXPECT_EQ(0U, allocator_->GetAsReference(&base_name, 0));
+
   // Ensure that the test-object can be made iterable.
   PersistentMemoryAllocator::Iterator iter1a(allocator_.get());
   EXPECT_EQ(0U, iter1a.GetLast());
   uint32_t type;
   EXPECT_EQ(0U, iter1a.GetNext(&type));
   allocator_->MakeIterable(block1);
   EXPECT_EQ(block1, iter1a.GetNext(&type));
   EXPECT_EQ(1U, type);
   EXPECT_EQ(block1, iter1a.GetLast());
   EXPECT_EQ(0U, iter1a.GetNext(&type));
@@ skipping 696 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