components/html_viewer/discardable_memory_allocator_unittest.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/html_viewer/discardable_memory_allocator.h"
   6
   7 #include "base/memory/discardable_memory.h"
   8 #include "testing/gtest/include/gtest/gtest.h"
   9
  10 namespace html_viewer {
  11 namespace {
  12
  13 const size_t kOneKilobyte = 1024;
  14 const size_t kAlmostOneMegabyte = 1023 * kOneKilobyte;
  15 const size_t kOneMegabyte = 1024 * kOneKilobyte;
  16
  17 TEST(DiscardableMemoryAllocator, Basic) {
  18   scoped_ptr<base::DiscardableMemory> chunk;
  19
  20   {
  21     DiscardableMemoryAllocator allocator(kOneMegabyte);
  22
  23     // Make sure the chunk is locked when allocated. In debug mode, we will
  24     // dcheck.
  25     chunk = allocator.AllocateLockedDiscardableMemory(kOneKilobyte);
  26     chunk->Unlock();
  27
  28     // Make sure we can lock a chunk.
  29     EXPECT_TRUE(chunk->Lock());
  30     chunk->Unlock();
  31   }
  32
  33   // The chunk's backing should have disappeared with the allocator.
  34   EXPECT_FALSE(chunk->Lock());
  35 }
  36
  37 TEST(DiscardableMemoryAllocator, DiscardChunks) {
  38   DiscardableMemoryAllocator allocator(kOneMegabyte);
  39
  40   scoped_ptr<base::DiscardableMemory> chunk_to_remove =
  41       allocator.AllocateLockedDiscardableMemory(kAlmostOneMegabyte);
  42   chunk_to_remove->Unlock();
  43
  44   // Allocating a second chunk should deallocate the first one due to memory
  45   // pressure, since we only have one megabyte available.
  46   scoped_ptr<base::DiscardableMemory> chunk_to_keep =
  47       allocator.AllocateLockedDiscardableMemory(kAlmostOneMegabyte);
  48
  49   // Fail to get a lock because allocating the second chunk removed the first.
  50   EXPECT_FALSE(chunk_to_remove->Lock());
  51
  52   chunk_to_keep->Unlock();
  53 }
  54
  55 TEST(DiscardableMemoryAllocator, DontDiscardLiveChunks) {
  56   DiscardableMemoryAllocator allocator(kOneMegabyte);
  57
  58   scoped_ptr<base::DiscardableMemory> chunk_one =
  59       allocator.AllocateLockedDiscardableMemory(kAlmostOneMegabyte);
  60   scoped_ptr<base::DiscardableMemory> chunk_two =
  61       allocator.AllocateLockedDiscardableMemory(kAlmostOneMegabyte);
  62   scoped_ptr<base::DiscardableMemory> chunk_three =
  63       allocator.AllocateLockedDiscardableMemory(kAlmostOneMegabyte);
  64
  65   // These accesses will fail if the underlying weak ptr has been deallocated.
  66   EXPECT_NE(nullptr, chunk_one->data());
  67   EXPECT_NE(nullptr, chunk_two->data());
  68   EXPECT_NE(nullptr, chunk_three->data());
  69
  70   chunk_one->Unlock();
  71   chunk_two->Unlock();
  72   chunk_three->Unlock();
  73 }
  74
  75 }  // namespace
  76 }  // namespace html_viewer