base/memory/discardable_memory.cc

   1 // Copyright 2014 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 "base/memory/discardable_memory.h"
   6
   7 #include "base/lazy_instance.h"
   8 #include "base/logging.h"
   9
  10 namespace base {
  11 namespace {
  12
  13 const struct TypeNamePair {
  14   DiscardableMemoryType type;
  15   const char* name;
  16 } kTypeNamePairs[] = {
  17   { DISCARDABLE_MEMORY_TYPE_ANDROID, "android" },
  18   { DISCARDABLE_MEMORY_TYPE_MAC, "mac" },
  19   { DISCARDABLE_MEMORY_TYPE_EMULATED, "emulated" }
  20 };
  21
  22 DiscardableMemoryType g_preferred_type = DISCARDABLE_MEMORY_TYPE_NONE;
  23
  24 struct DefaultPreferredType {
  25   DefaultPreferredType() : value(DISCARDABLE_MEMORY_TYPE_NONE) {
  26     std::vector<DiscardableMemoryType> supported_types;
  27     DiscardableMemory::GetSupportedTypes(&supported_types);
  28     DCHECK(!supported_types.empty());
  29     value = supported_types[0];
  30   }
  31   DiscardableMemoryType value;
  32 };
  33 LazyInstance<DefaultPreferredType>::Leaky g_default_preferred_type =
  34     LAZY_INSTANCE_INITIALIZER;
  35
  36 }  // namespace
  37
  38 // static
  39 DiscardableMemoryType DiscardableMemory::GetNamedType(
  40     const std::string& name) {
  41   for (size_t i = 0; i < arraysize(kTypeNamePairs); ++i) {
  42     if (name == kTypeNamePairs[i].name)
  43       return kTypeNamePairs[i].type;
  44   }
  45
  46   return DISCARDABLE_MEMORY_TYPE_NONE;
  47 }
  48
  49 // static
  50 const char* DiscardableMemory::GetTypeName(DiscardableMemoryType type) {
  51   for (size_t i = 0; i < arraysize(kTypeNamePairs); ++i) {
  52     if (type == kTypeNamePairs[i].type)
  53       return kTypeNamePairs[i].name;
  54   }
  55
  56   return "unknown";
  57 }
  58
  59 // static
  60 void DiscardableMemory::SetPreferredType(DiscardableMemoryType type) {
  61   // NONE is a reserved value and not a valid default type.
  62   DCHECK_NE(DISCARDABLE_MEMORY_TYPE_NONE, type);
  63
  64   // Make sure this function is only called once before the first call
  65   // to GetPreferredType().
  66   DCHECK_EQ(DISCARDABLE_MEMORY_TYPE_NONE, g_preferred_type);
  67
  68   g_preferred_type = type;
  69 }
  70
  71 // static
  72 DiscardableMemoryType DiscardableMemory::GetPreferredType() {
  73   if (g_preferred_type == DISCARDABLE_MEMORY_TYPE_NONE)
  74     g_preferred_type = g_default_preferred_type.Get().value;
  75
  76   return g_preferred_type;
  77 }
  78
  79 // static
  80 scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemory(
  81     size_t size) {
  82   return CreateLockedMemoryWithType(GetPreferredType(), size);
  83 }
  84
  85 }  // namespace base