blob: a0cf3cccd9a58e1edbba7c642908204826e342ad [file] [log] [blame]
// Copyright (c) 2006-2008 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 "net/disk_cache/mem_backend_impl.h"
#include "base/sys_info.h"
#include "net/disk_cache/cache_util.h"
#include "net/disk_cache/mem_entry_impl.h"
using base::Time;
namespace {
const int kDefaultCacheSize = 10 * 1024 * 1024;
const int kCleanUpMargin = 1024 * 1024;
int LowWaterAdjust(int high_water) {
if (high_water < kCleanUpMargin)
return 0;
return high_water - kCleanUpMargin;
}
} // namespace
namespace disk_cache {
Backend* CreateInMemoryCacheBackend(int max_bytes) {
MemBackendImpl* cache = new MemBackendImpl();
cache->SetMaxSize(max_bytes);
if (cache->Init())
return cache;
delete cache;
LOG(ERROR) << "Unable to create cache";
return NULL;
}
// ------------------------------------------------------------------------
bool MemBackendImpl::Init() {
if (max_size_)
return true;
int64 total_memory = base::SysInfo::AmountOfPhysicalMemory();
if (total_memory <= 0) {
max_size_ = kDefaultCacheSize;
return true;
}
// We want to use up to 2% of the computer's memory, with a limit of 50 MB,
// reached on systemd with more than 2.5 GB of RAM.
total_memory = total_memory * 2 / 100;
if (total_memory > kDefaultCacheSize * 5)
max_size_ = kDefaultCacheSize * 5;
else
max_size_ = static_cast<int32>(total_memory);
return true;
}
MemBackendImpl::~MemBackendImpl() {
EntryMap::iterator it = entries_.begin();
while (it != entries_.end()) {
it->second->Doom();
it = entries_.begin();
}
DCHECK(!current_size_);
}
bool MemBackendImpl::SetMaxSize(int max_bytes) {
COMPILE_ASSERT(sizeof(max_bytes) == sizeof(max_size_), unsupported_int_model);
if (max_bytes < 0)
return false;
// Zero size means use the default.
if (!max_bytes)
return true;
max_size_ = max_bytes;
return true;
}
int32 MemBackendImpl::GetEntryCount() const {
return static_cast<int32>(entries_.size());
}
bool MemBackendImpl::OpenEntry(const std::string& key, Entry** entry) {
EntryMap::iterator it = entries_.find(key);
if (it == entries_.end())
return false;
it->second->Open();
*entry = it->second;
return true;
}
bool MemBackendImpl::CreateEntry(const std::string& key, Entry** entry) {
EntryMap::iterator it = entries_.find(key);
if (it != entries_.end())
return false;
MemEntryImpl* cache_entry = new MemEntryImpl(this);
if (!cache_entry->CreateEntry(key)) {
delete entry;
return false;
}
rankings_.Insert(cache_entry);
entries_[key] = cache_entry;
*entry = cache_entry;
return true;
}
bool MemBackendImpl::DoomEntry(const std::string& key) {
Entry* entry;
if (!OpenEntry(key, &entry))
return false;
entry->Doom();
entry->Close();
return true;
}
void MemBackendImpl::InternalDoomEntry(MemEntryImpl* entry) {
rankings_.Remove(entry);
EntryMap::iterator it = entries_.find(entry->GetKey());
if (it != entries_.end())
entries_.erase(it);
else
NOTREACHED();
entry->InternalDoom();
}
bool MemBackendImpl::DoomAllEntries() {
TrimCache(true);
return true;
}
bool MemBackendImpl::DoomEntriesBetween(const Time initial_time,
const Time end_time) {
if (end_time.is_null())
return DoomEntriesSince(initial_time);
DCHECK(end_time >= initial_time);
MemEntryImpl* next = rankings_.GetNext(NULL);
// rankings_ is ordered by last used, this will descend through the cache
// and start dooming items before the end_time, and will stop once it reaches
// an item used before the initial time.
while (next) {
MemEntryImpl* node = next;
next = rankings_.GetNext(next);
if (node->GetLastUsed() < initial_time)
break;
if (node->GetLastUsed() < end_time) {
node->Doom();
}
}
return true;
}
// We use OpenNextEntry to retrieve elements from the cache, until we get
// entries that are too old.
bool MemBackendImpl::DoomEntriesSince(const Time initial_time) {
for (;;) {
Entry* entry;
void* iter = NULL;
if (!OpenNextEntry(&iter, &entry))
return true;
if (initial_time > entry->GetLastUsed()) {
entry->Close();
EndEnumeration(&iter);
return true;
}
entry->Doom();
entry->Close();
EndEnumeration(&iter); // Dooming the entry invalidates the iterator.
}
}
bool MemBackendImpl::OpenNextEntry(void** iter, Entry** next_entry) {
MemEntryImpl* current = reinterpret_cast<MemEntryImpl*>(*iter);
MemEntryImpl* node = rankings_.GetNext(current);
*next_entry = node;
*iter = node;
if (node)
node->Open();
return NULL != node;
}
void MemBackendImpl::EndEnumeration(void** iter) {
*iter = NULL;
}
void MemBackendImpl::TrimCache(bool empty) {
MemEntryImpl* next = rankings_.GetPrev(NULL);
DCHECK(next);
int target_size = empty ? 0 : LowWaterAdjust(max_size_);
while (current_size_ > target_size && next) {
MemEntryImpl* node = next;
next = rankings_.GetPrev(next);
if (!node->InUse() || empty) {
node->Doom();
}
}
return;
}
void MemBackendImpl::AddStorageSize(int32 bytes) {
current_size_ += bytes;
DCHECK(current_size_ >= 0);
if (current_size_ > max_size_)
TrimCache(false);
}
void MemBackendImpl::SubstractStorageSize(int32 bytes) {
current_size_ -= bytes;
DCHECK(current_size_ >= 0);
}
void MemBackendImpl::ModifyStorageSize(int32 old_size, int32 new_size) {
if (old_size >= new_size)
SubstractStorageSize(old_size - new_size);
else
AddStorageSize(new_size - old_size);
}
void MemBackendImpl::UpdateRank(MemEntryImpl* node) {
rankings_.UpdateRank(node);
}
int MemBackendImpl::MaxFileSize() const {
return max_size_ / 8;
}
} // namespace disk_cache