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// Copyright 2013 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/memory/discardable_memory_emulated.h"
#include "base/lazy_instance.h"
#include "base/memory/discardable_memory_manager.h"
namespace base {
namespace {
// This is admittedly pretty magical.
const size_t kEmulatedMemoryLimit = 512 * 1024 * 1024;
const size_t kEmulatedSoftMemoryLimit = 32 * 1024 * 1024;
const size_t kEmulatedBytesToKeepUnderModeratePressure = 4 * 1024 * 1024;
const size_t kEmulatedHardMemoryLimitExpirationTimeMs = 1000;
struct SharedState {
SharedState()
: manager(kEmulatedMemoryLimit,
kEmulatedSoftMemoryLimit,
kEmulatedBytesToKeepUnderModeratePressure,
TimeDelta::FromMilliseconds(
kEmulatedHardMemoryLimitExpirationTimeMs)) {}
internal::DiscardableMemoryManager manager;
};
LazyInstance<SharedState>::Leaky g_shared_state = LAZY_INSTANCE_INITIALIZER;
} // namespace
namespace internal {
DiscardableMemoryEmulated::DiscardableMemoryEmulated(size_t bytes)
: bytes_(bytes),
is_locked_(false) {
g_shared_state.Pointer()->manager.Register(this, bytes);
}
DiscardableMemoryEmulated::~DiscardableMemoryEmulated() {
if (is_locked_)
Unlock();
g_shared_state.Pointer()->manager.Unregister(this);
}
// static
void DiscardableMemoryEmulated::RegisterMemoryPressureListeners() {
g_shared_state.Pointer()->manager.RegisterMemoryPressureListener();
}
// static
void DiscardableMemoryEmulated::UnregisterMemoryPressureListeners() {
g_shared_state.Pointer()->manager.UnregisterMemoryPressureListener();
}
// static
bool DiscardableMemoryEmulated::ReduceMemoryUsage() {
return g_shared_state.Pointer()->manager.ReduceMemoryUsage();
}
// static
void DiscardableMemoryEmulated::PurgeForTesting() {
g_shared_state.Pointer()->manager.PurgeAll();
}
bool DiscardableMemoryEmulated::Initialize() {
return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
}
DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
DCHECK(!is_locked_);
bool purged = false;
if (!g_shared_state.Pointer()->manager.AcquireLock(this, &purged))
return DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
is_locked_ = true;
return purged ? DISCARDABLE_MEMORY_LOCK_STATUS_PURGED
: DISCARDABLE_MEMORY_LOCK_STATUS_SUCCESS;
}
void DiscardableMemoryEmulated::Unlock() {
DCHECK(is_locked_);
g_shared_state.Pointer()->manager.ReleaseLock(this);
is_locked_ = false;
}
void* DiscardableMemoryEmulated::Memory() const {
DCHECK(is_locked_);
DCHECK(memory_);
return memory_.get();
}
bool DiscardableMemoryEmulated::AllocateAndAcquireLock() {
if (memory_)
return true;
memory_.reset(new uint8[bytes_]);
return false;
}
void DiscardableMemoryEmulated::Purge() {
memory_.reset();
}
} // namespace internal
} // namespace base
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