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