// Copyright (c) 2011 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/entry_impl.h"
#include "base/message_loop.h"
#include "base/metrics/histogram.h"
#include "base/string_util.h"
#include "net/base/io_buffer.h"
#include "net/base/net_errors.h"
#include "net/disk_cache/backend_impl.h"
#include "net/disk_cache/bitmap.h"
#include "net/disk_cache/cache_util.h"
#include "net/disk_cache/hash.h"
#include "net/disk_cache/histogram_macros.h"
#include "net/disk_cache/net_log_parameters.h"
#include "net/disk_cache/sparse_control.h"
using base::Time;
using base::TimeDelta;
using base::TimeTicks;
namespace {
// Index for the file used to store the key, if any (files_[kKeyFileIndex]).
const int kKeyFileIndex = 3;
// This class implements FileIOCallback to buffer the callback from a file IO
// operation from the actual net class.
class SyncCallback: public disk_cache::FileIOCallback {
public:
// |end_event_type| is the event type to log on completion. Logs nothing on
// discard, or when the NetLog is not set to log all events.
SyncCallback(disk_cache::EntryImpl* entry, net::IOBuffer* buffer,
net::CompletionCallback* callback,
net::NetLog::EventType end_event_type)
: entry_(entry), callback_(callback), buf_(buffer),
start_(TimeTicks::Now()), end_event_type_(end_event_type) {
entry->AddRef();
entry->IncrementIoCount();
}
~SyncCallback() {}
virtual void OnFileIOComplete(int bytes_copied);
void Discard();
private:
disk_cache::EntryImpl* entry_;
net::CompletionCallback* callback_;
scoped_refptr<net::IOBuffer> buf_;
TimeTicks start_;
const net::NetLog::EventType end_event_type_;
DISALLOW_COPY_AND_ASSIGN(SyncCallback);
};
void SyncCallback::OnFileIOComplete(int bytes_copied) {
entry_->DecrementIoCount();
if (callback_) {
if (entry_->net_log().IsLoggingAllEvents()) {
entry_->net_log().EndEvent(
end_event_type_,
make_scoped_refptr(
new disk_cache::ReadWriteCompleteParameters(bytes_copied)));
}
entry_->ReportIOTime(disk_cache::EntryImpl::kAsyncIO, start_);
callback_->Run(bytes_copied);
}
entry_->Release();
delete this;
}
void SyncCallback::Discard() {
callback_ = NULL;
buf_ = NULL;
OnFileIOComplete(0);
}
const int kMaxBufferSize = 1024 * 1024; // 1 MB.
} // namespace
namespace disk_cache {
// This class handles individual memory buffers that store data before it is
// sent to disk. The buffer can start at any offset, but if we try to write to
// anywhere in the first 16KB of the file (kMaxBlockSize), we set the offset to
// zero. The buffer grows up to a size determined by the backend, to keep the
// total memory used under control.
class EntryImpl::UserBuffer {
public:
explicit UserBuffer(BackendImpl* backend)
: backend_(backend->GetWeakPtr()), offset_(0), grow_allowed_(true) {
buffer_.reserve(kMaxBlockSize);
}
~UserBuffer() {
if (backend_)
backend_->BufferDeleted(capacity() - kMaxBlockSize);
}
// Returns true if we can handle writing |len| bytes to |offset|.
bool PreWrite(int offset, int len);
// Truncates the buffer to |offset| bytes.
void Truncate(int offset);
// Writes |len| bytes from |buf| at the given |offset|.
void Write(int offset, net::IOBuffer* buf, int len);
// Returns true if we can read |len| bytes from |offset|, given that the
// actual file has |eof| bytes stored. Note that the number of bytes to read
// may be modified by this method even though it returns false: that means we
// should do a smaller read from disk.
bool PreRead(int eof, int offset, int* len);
// Read |len| bytes from |buf| at the given |offset|.
int Read(int offset, net::IOBuffer* buf, int len);
// Prepare this buffer for reuse.
void Reset();
char* Data() { return buffer_.size() ? &buffer_[0] : NULL; }
int Size() { return static_cast<int>(buffer_.size()); }
int Start() { return offset_; }
int End() { return offset_ + Size(); }
private:
int capacity() { return static_cast<int>(buffer_.capacity()); }
bool GrowBuffer(int required, int limit);
base::WeakPtr<BackendImpl> backend_;
int offset_;
std::vector<char> buffer_;
bool grow_allowed_;
DISALLOW_COPY_AND_ASSIGN(UserBuffer);
};
bool EntryImpl::UserBuffer::PreWrite(int offset, int len) {
DCHECK_GE(offset, 0);
DCHECK_GE(len, 0);
DCHECK_GE(offset + len, 0);
// We don't want to write before our current start.
if (offset < offset_)
return false;
// Lets get the common case out of the way.
if (offset + len <= capacity())
return true;
// If we are writing to the first 16K (kMaxBlockSize), we want to keep the
// buffer offset_ at 0.
if (!Size() && offset > kMaxBlockSize)
return GrowBuffer(len, kMaxBufferSize);
int required = offset - offset_ + len;
return GrowBuffer(required, kMaxBufferSize * 6 / 5);
}
void EntryImpl::UserBuffer::Truncate(int offset) {
DCHECK_GE(offset, 0);
DCHECK_GE(offset, offset_);
DVLOG(3) << "Buffer truncate at " << offset << " current " << offset_;
offset -= offset_;
if (Size() >= offset)
buffer_.resize(offset);
}
void EntryImpl::UserBuffer::Write(int offset, net::IOBuffer* buf, int len) {
DCHECK_GE(offset, 0);
DCHECK_GE(len, 0);
DCHECK_GE(offset + len, 0);
DCHECK_GE(offset, offset_);
DVLOG(3) << "Buffer write at " << offset << " current " << offset_;
if (!Size() && offset > kMaxBlockSize)
offset_ = offset;
offset -= offset_;
if (offset > Size())
buffer_.resize(offset);
if (!len)
return;
char* buffer = buf->data();
int valid_len = Size() - offset;
int copy_len = std::min(valid_len, len);
if (copy_len) {
memcpy(&buffer_[offset], buffer, copy_len);
len -= copy_len;
buffer += copy_len;
}
if (!len)
return;
buffer_.insert(buffer_.end(), buffer, buffer + len);
}
bool EntryImpl::UserBuffer::PreRead(int eof, int offset, int* len) {
DCHECK_GE(offset, 0);
DCHECK_GT(*len, 0);
if (offset < offset_) {
// We are reading before this buffer.
if (offset >= eof)
return true;
// If the read overlaps with the buffer, change its length so that there is
// no overlap.
*len = std::min(*len, offset_ - offset);
*len = std::min(*len, eof - offset);
// We should read from disk.
return false;
}
if (!Size())
return false;
// See if we can fulfill the first part of the operation.
return (offset - offset_ < Size());
}
int EntryImpl::UserBuffer::Read(int offset, net::IOBuffer* buf, int len) {
DCHECK_GE(offset, 0);
DCHECK_GT(len, 0);
DCHECK(Size() || offset < offset_);
int clean_bytes = 0;
if (offset < offset_) {
// We don't have a file so lets fill the first part with 0.
clean_bytes = std::min(offset_ - offset, len);
memset(buf->data(), 0, clean_bytes);
if (len == clean_bytes)
return len;
offset = offset_;
len -= clean_bytes;
}
int start = offset - offset_;
int available = Size() - start;
DCHECK_GE(start, 0);
DCHECK_GE(available, 0);
len = std::min(len, available);
memcpy(buf->data() + clean_bytes, &buffer_[start], len);
return len + clean_bytes;
}
void EntryImpl::UserBuffer::Reset() {
if (!grow_allowed_) {
if (backend_)
backend_->BufferDeleted(capacity() - kMaxBlockSize);
grow_allowed_ = true;
std::vector<char> tmp;
buffer_.swap(tmp);
buffer_.reserve(kMaxBlockSize);
}
offset_ = 0;
buffer_.clear();
}
bool EntryImpl::UserBuffer::GrowBuffer(int required, int limit) {
DCHECK_GE(required, 0);
int current_size = capacity();
if (required <= current_size)
return true;
if (required > limit)
return false;
if (!backend_)
return false;
int to_add = std::max(required - current_size, kMaxBlockSize * 4);
to_add = std::max(current_size, to_add);
required = std::min(current_size + to_add, limit);
grow_allowed_ = backend_->IsAllocAllowed(current_size, required);
if (!grow_allowed_)
return false;
DVLOG(3) << "Buffer grow to " << required;
buffer_.reserve(required);
return true;
}
// ------------------------------------------------------------------------
EntryImpl::EntryImpl(BackendImpl* backend, Addr address, bool read_only)
: entry_(NULL, Addr(0)), node_(NULL, Addr(0)), backend_(backend),
doomed_(false), read_only_(read_only), dirty_(false) {
entry_.LazyInit(backend->File(address), address);
for (int i = 0; i < kNumStreams; i++) {
unreported_size_[i] = 0;
}
}
void EntryImpl::DoomImpl() {
if (doomed_)
return;
SetPointerForInvalidEntry(backend_->GetCurrentEntryId());
backend_->InternalDoomEntry(this);
}
int EntryImpl::ReadDataImpl(int index, int offset, net::IOBuffer* buf,
int buf_len, CompletionCallback* callback) {
if (net_log_.IsLoggingAllEvents()) {
net_log_.BeginEvent(
net::NetLog::TYPE_ENTRY_READ_DATA,
make_scoped_refptr(
new ReadWriteDataParameters(index, offset, buf_len, false)));
}
int result = InternalReadData(index, offset, buf, buf_len, callback);
if (result != net::ERR_IO_PENDING && net_log_.IsLoggingAllEvents()) {
net_log_.EndEvent(
net::NetLog::TYPE_ENTRY_READ_DATA,
make_scoped_refptr(new ReadWriteCompleteParameters(result)));
}
return result;
}
int EntryImpl::WriteDataImpl(int index, int offset, net::IOBuffer* buf,
int buf_len, CompletionCallback* callback,
bool truncate) {
if (net_log_.IsLoggingAllEvents()) {
net_log_.BeginEvent(
net::NetLog::TYPE_ENTRY_WRITE_DATA,
make_scoped_refptr(
new ReadWriteDataParameters(index, offset, buf_len, truncate)));
}
int result = InternalWriteData(index, offset, buf, buf_len, callback,
truncate);
if (result != net::ERR_IO_PENDING && net_log_.IsLoggingAllEvents()) {
net_log_.EndEvent(
net::NetLog::TYPE_ENTRY_WRITE_DATA,
make_scoped_refptr(new ReadWriteCompleteParameters(result)));
}
return result;
}
int EntryImpl::ReadSparseDataImpl(int64 offset, net::IOBuffer* buf, int buf_len,
CompletionCallback* callback) {
DCHECK(node_.Data()->dirty || read_only_);
int result = InitSparseData();
if (net::OK != result)
return result;
TimeTicks start = TimeTicks::Now();
result = sparse_->StartIO(SparseControl::kReadOperation, offset, buf, buf_len,
callback);
ReportIOTime(kSparseRead, start);
return result;
}
int EntryImpl::WriteSparseDataImpl(int64 offset, net::IOBuffer* buf,
int buf_len, CompletionCallback* callback) {
DCHECK(node_.Data()->dirty || read_only_);
int result = InitSparseData();
if (net::OK != result)
return result;
TimeTicks start = TimeTicks::Now();
result = sparse_->StartIO(SparseControl::kWriteOperation, offset, buf,
buf_len, callback);
ReportIOTime(kSparseWrite, start);
return result;
}
int EntryImpl::GetAvailableRangeImpl(int64 offset, int len, int64* start) {
int result = InitSparseData();
if (net::OK != result)
return result;
return sparse_->GetAvailableRange(offset, len, start);
}
void EntryImpl::CancelSparseIOImpl() {
if (!sparse_.get())
return;
sparse_->CancelIO();
}
int EntryImpl::ReadyForSparseIOImpl(CompletionCallback* callback) {
DCHECK(sparse_.get());
return sparse_->ReadyToUse(callback);
}
uint32 EntryImpl::GetHash() {
return entry_.Data()->hash;
}
bool EntryImpl::CreateEntry(Addr node_address, const std::string& key,
uint32 hash) {
Trace("Create entry In");
EntryStore* entry_store = entry_.Data();
RankingsNode* node = node_.Data();
memset(entry_store, 0, sizeof(EntryStore) * entry_.address().num_blocks());
memset(node, 0, sizeof(RankingsNode));
if (!node_.LazyInit(backend_->File(node_address), node_address))
return false;
entry_store->rankings_node = node_address.value();
node->contents = entry_.address().value();
entry_store->hash = hash;
entry_store->creation_time = Time::Now().ToInternalValue();
entry_store->key_len = static_cast<int32>(key.size());
if (entry_store->key_len > kMaxInternalKeyLength) {
Addr address(0);
if (!CreateBlock(entry_store->key_len + 1, &address))
return false;
entry_store->long_key = address.value();
File* key_file = GetBackingFile(address, kKeyFileIndex);
key_ = key;
size_t offset = 0;
if (address.is_block_file())
offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
if (!key_file || !key_file->Write(key.data(), key.size(), offset)) {
DeleteData(address, kKeyFileIndex);
return false;
}
if (address.is_separate_file())
key_file->SetLength(key.size() + 1);
} else {
memcpy(entry_store->key, key.data(), key.size());
entry_store->key[key.size()] = '\0';
}
backend_->ModifyStorageSize(0, static_cast<int32>(key.size()));
CACHE_UMA(COUNTS, "KeySize", 0, static_cast<int32>(key.size()));
node->dirty = backend_->GetCurrentEntryId();
Log("Create Entry ");
return true;
}
bool EntryImpl::IsSameEntry(const std::string& key, uint32 hash) {
if (entry_.Data()->hash != hash ||
static_cast<size_t>(entry_.Data()->key_len) != key.size())
return false;
std::string my_key = GetKey();
return key.compare(my_key) ? false : true;
}
void EntryImpl::InternalDoom() {
net_log_.AddEvent(net::NetLog::TYPE_ENTRY_DOOM, NULL);
DCHECK(node_.HasData());
if (!node_.Data()->dirty) {
node_.Data()->dirty = backend_->GetCurrentEntryId();
node_.Store();
}
doomed_ = true;
}
void EntryImpl::DeleteEntryData(bool everything) {
DCHECK(doomed_ || !everything);
if (GetEntryFlags() & PARENT_ENTRY) {
// We have some child entries that must go away.
SparseControl::DeleteChildren(this);
}
if (GetDataSize(0))
CACHE_UMA(COUNTS, "DeleteHeader", 0, GetDataSize(0));
if (GetDataSize(1))
CACHE_UMA(COUNTS, "DeleteData", 0, GetDataSize(1));
for (int index = 0; index < kNumStreams; index++) {
Addr address(entry_.Data()->data_addr[index]);
if (address.is_initialized()) {
backend_->ModifyStorageSize(entry_.Data()->data_size[index] -
unreported_size_[index], 0);
entry_.Data()->data_addr[index] = 0;
entry_.Data()->data_size[index] = 0;
entry_.Store();
DeleteData(address, index);
}
}
if (!everything)
return;
// Remove all traces of this entry.
backend_->RemoveEntry(this);
Addr address(entry_.Data()->long_key);
DeleteData(address, kKeyFileIndex);
backend_->ModifyStorageSize(entry_.Data()->key_len, 0);
memset(node_.buffer(), 0, node_.size());
memset(entry_.buffer(), 0, entry_.size());
node_.Store();
entry_.Store();
backend_->DeleteBlock(node_.address(), false);
backend_->DeleteBlock(entry_.address(), false);
}
CacheAddr EntryImpl::GetNextAddress() {
return entry_.Data()->next;
}
void EntryImpl::SetNextAddress(Addr address) {
DCHECK_NE(address.value(), entry_.address().value());
entry_.Data()->next = address.value();
bool success = entry_.Store();
DCHECK(success);
}
bool EntryImpl::LoadNodeAddress() {
Addr address(entry_.Data()->rankings_node);
if (!node_.LazyInit(backend_->File(address), address))
return false;
return node_.Load();
}
bool EntryImpl::Update() {
DCHECK(node_.HasData());
if (read_only_)
return true;
RankingsNode* rankings = node_.Data();
if (!rankings->dirty) {
rankings->dirty = backend_->GetCurrentEntryId();
if (!node_.Store())
return false;
}
return true;
}
void EntryImpl::SetDirtyFlag(int32 current_id) {
DCHECK(node_.HasData());
// We are checking if the entry is valid or not. If there is a pointer here,
// we should not be checking the entry.
if (node_.Data()->dummy)
dirty_ = true;
if (node_.Data()->dirty && current_id != node_.Data()->dirty)
dirty_ = true;
}
void EntryImpl::SetPointerForInvalidEntry(int32 new_id) {
node_.Data()->dirty = new_id;
node_.Data()->dummy = 0;
node_.Store();
}
bool EntryImpl::SanityCheck() {
EntryStore* stored = entry_.Data();
if (!stored->rankings_node || stored->key_len <= 0)
return false;
if (stored->reuse_count < 0 || stored->refetch_count < 0)
return false;
Addr rankings_addr(stored->rankings_node);
if (!rankings_addr.is_initialized() || rankings_addr.is_separate_file() ||
rankings_addr.file_type() != RANKINGS)
return false;
Addr next_addr(stored->next);
if (next_addr.is_initialized() &&
(next_addr.is_separate_file() || next_addr.file_type() != BLOCK_256))
return false;
if (!rankings_addr.SanityCheck() || !next_addr.SanityCheck())
return false;
if (stored->state > ENTRY_DOOMED || stored->state < ENTRY_NORMAL)
return false;
Addr key_addr(stored->long_key);
if (stored->key_len <= kMaxInternalKeyLength && key_addr.is_initialized())
return false;
if (!key_addr.SanityCheck())
return false;
if (stored->hash != Hash(GetKey()))
return false;
for (int i = 0; i < kNumStreams; i++) {
Addr data_addr(stored->data_addr[i]);
int data_size = stored->data_size[i];
if (data_size < 0)
return false;
if (!data_size && data_addr.is_initialized())
return false;
if (!data_addr.SanityCheck())
return false;
if (!data_size)
continue;
if (data_size <= kMaxBlockSize && data_addr.is_separate_file())
return false;
if (data_size > kMaxBlockSize && data_addr.is_block_file())
return false;
}
return true;
}
void EntryImpl::IncrementIoCount() {
backend_->IncrementIoCount();
}
void EntryImpl::DecrementIoCount() {
backend_->DecrementIoCount();
}
void EntryImpl::SetTimes(base::Time last_used, base::Time last_modified) {
node_.Data()->last_used = last_used.ToInternalValue();
node_.Data()->last_modified = last_modified.ToInternalValue();
node_.set_modified();
}
void EntryImpl::ReportIOTime(Operation op, const base::TimeTicks& start) {
int group = backend_->GetSizeGroup();
switch (op) {
case kRead:
CACHE_UMA(AGE_MS, "ReadTime", group, start);
break;
case kWrite:
CACHE_UMA(AGE_MS, "WriteTime", group, start);
break;
case kSparseRead:
CACHE_UMA(AGE_MS, "SparseReadTime", 0, start);
break;
case kSparseWrite:
CACHE_UMA(AGE_MS, "SparseWriteTime", 0, start);
break;
case kAsyncIO:
CACHE_UMA(AGE_MS, "AsyncIOTime", group, start);
break;
default:
NOTREACHED();
}
}
void EntryImpl::BeginLogging(net::NetLog* net_log, bool created) {
DCHECK(!net_log_.net_log());
net_log_ = net::BoundNetLog::Make(
net_log, net::NetLog::SOURCE_DISK_CACHE_ENTRY);
net_log_.BeginEvent(
net::NetLog::TYPE_DISK_CACHE_ENTRY_IMPL,
make_scoped_refptr(new EntryCreationParameters(GetKey(), created)));
}
const net::BoundNetLog& EntryImpl::net_log() const {
return net_log_;
}
void EntryImpl::Doom() {
backend_->background_queue()->DoomEntryImpl(this);
}
void EntryImpl::Close() {
backend_->background_queue()->CloseEntryImpl(this);
}
std::string EntryImpl::GetKey() const {
CacheEntryBlock* entry = const_cast<CacheEntryBlock*>(&entry_);
if (entry->Data()->key_len <= kMaxInternalKeyLength)
return std::string(entry->Data()->key);
// We keep a copy of the key so that we can always return it, even if the
// backend is disabled.
if (!key_.empty())
return key_;
Addr address(entry->Data()->long_key);
DCHECK(address.is_initialized());
size_t offset = 0;
if (address.is_block_file())
offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
COMPILE_ASSERT(kNumStreams == kKeyFileIndex, invalid_key_index);
File* key_file = const_cast<EntryImpl*>(this)->GetBackingFile(address,
kKeyFileIndex);
if (!key_file ||
!key_file->Read(WriteInto(&key_, entry->Data()->key_len + 1),
entry->Data()->key_len + 1, offset))
key_.clear();
return key_;
}
Time EntryImpl::GetLastUsed() const {
CacheRankingsBlock* node = const_cast<CacheRankingsBlock*>(&node_);
return Time::FromInternalValue(node->Data()->last_used);
}
Time EntryImpl::GetLastModified() const {
CacheRankingsBlock* node = const_cast<CacheRankingsBlock*>(&node_);
return Time::FromInternalValue(node->Data()->last_modified);
}
int32 EntryImpl::GetDataSize(int index) const {
if (index < 0 || index >= kNumStreams)
return 0;
CacheEntryBlock* entry = const_cast<CacheEntryBlock*>(&entry_);
return entry->Data()->data_size[index];
}
int EntryImpl::ReadData(int index, int offset, net::IOBuffer* buf, int buf_len,
net::CompletionCallback* callback) {
if (!callback)
return ReadDataImpl(index, offset, buf, buf_len, callback);
DCHECK(node_.Data()->dirty || read_only_);
if (index < 0 || index >= kNumStreams)
return net::ERR_INVALID_ARGUMENT;
int entry_size = entry_.Data()->data_size[index];
if (offset >= entry_size || offset < 0 || !buf_len)
return 0;
if (buf_len < 0)
return net::ERR_INVALID_ARGUMENT;
backend_->background_queue()->ReadData(this, index, offset, buf, buf_len,
callback);
return net::ERR_IO_PENDING;
}
int EntryImpl::WriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
CompletionCallback* callback, bool truncate) {
if (!callback)
return WriteDataImpl(index, offset, buf, buf_len, callback, truncate);
DCHECK(node_.Data()->dirty || read_only_);
if (index < 0 || index >= kNumStreams)
return net::ERR_INVALID_ARGUMENT;
if (offset < 0 || buf_len < 0)
return net::ERR_INVALID_ARGUMENT;
backend_->background_queue()->WriteData(this, index, offset, buf, buf_len,
truncate, callback);
return net::ERR_IO_PENDING;
}
int EntryImpl::ReadSparseData(int64 offset, net::IOBuffer* buf, int buf_len,
net::CompletionCallback* callback) {
if (!callback)
return ReadSparseDataImpl(offset, buf, buf_len, callback);
backend_->background_queue()->ReadSparseData(this, offset, buf, buf_len,
callback);
return net::ERR_IO_PENDING;
}
int EntryImpl::WriteSparseData(int64 offset, net::IOBuffer* buf, int buf_len,
net::CompletionCallback* callback) {
if (!callback)
return WriteSparseDataImpl(offset, buf, buf_len, callback);
backend_->background_queue()->WriteSparseData(this, offset, buf, buf_len,
callback);
return net::ERR_IO_PENDING;
}
int EntryImpl::GetAvailableRange(int64 offset, int len, int64* start,
CompletionCallback* callback) {
backend_->background_queue()->GetAvailableRange(this, offset, len, start,
callback);
return net::ERR_IO_PENDING;
}
bool EntryImpl::CouldBeSparse() const {
if (sparse_.get())
return true;
scoped_ptr<SparseControl> sparse;
sparse.reset(new SparseControl(const_cast<EntryImpl*>(this)));
return sparse->CouldBeSparse();
}
void EntryImpl::CancelSparseIO() {
backend_->background_queue()->CancelSparseIO(this);
}
int EntryImpl::ReadyForSparseIO(net::CompletionCallback* callback) {
if (!sparse_.get())
return net::OK;
backend_->background_queue()->ReadyForSparseIO(this, callback);
return net::ERR_IO_PENDING;
}
// When an entry is deleted from the cache, we clean up all the data associated
// with it for two reasons: to simplify the reuse of the block (we know that any
// unused block is filled with zeros), and to simplify the handling of write /
// read partial information from an entry (don't have to worry about returning
// data related to a previous cache entry because the range was not fully
// written before).
EntryImpl::~EntryImpl() {
Log("~EntryImpl in");
// Save the sparse info to disk. This will generate IO for this entry and
// maybe for a child entry, so it is important to do it before deleting this
// entry.
sparse_.reset();
// Remove this entry from the list of open entries.
backend_->OnEntryDestroyBegin(entry_.address());
if (doomed_) {
DeleteEntryData(true);
} else {
net_log_.AddEvent(net::NetLog::TYPE_ENTRY_CLOSE, NULL);
bool ret = true;
for (int index = 0; index < kNumStreams; index++) {
if (user_buffers_[index].get()) {
if (!(ret = Flush(index, 0)))
LOG(ERROR) << "Failed to save user data";
}
if (unreported_size_[index]) {
backend_->ModifyStorageSize(
entry_.Data()->data_size[index] - unreported_size_[index],
entry_.Data()->data_size[index]);
}
}
if (!ret) {
// There was a failure writing the actual data. Mark the entry as dirty.
int current_id = backend_->GetCurrentEntryId();
node_.Data()->dirty = current_id == 1 ? -1 : current_id - 1;
node_.Store();
} else if (node_.HasData() && !dirty_) {
node_.Data()->dirty = 0;
node_.Store();
}
}
Trace("~EntryImpl out 0x%p", reinterpret_cast<void*>(this));
net_log_.EndEvent(net::NetLog::TYPE_DISK_CACHE_ENTRY_IMPL, NULL);
backend_->OnEntryDestroyEnd();
}
// ------------------------------------------------------------------------
int EntryImpl::InternalReadData(int index, int offset, net::IOBuffer* buf,
int buf_len, CompletionCallback* callback) {
DCHECK(node_.Data()->dirty || read_only_);
DVLOG(2) << "Read from " << index << " at " << offset << " : " << buf_len;
if (index < 0 || index >= kNumStreams)
return net::ERR_INVALID_ARGUMENT;
int entry_size = entry_.Data()->data_size[index];
if (offset >= entry_size || offset < 0 || !buf_len)
return 0;
if (buf_len < 0)
return net::ERR_INVALID_ARGUMENT;
TimeTicks start = TimeTicks::Now();
if (offset + buf_len > entry_size)
buf_len = entry_size - offset;
UpdateRank(false);
backend_->OnEvent(Stats::READ_DATA);
backend_->OnRead(buf_len);
Addr address(entry_.Data()->data_addr[index]);
int eof = address.is_initialized() ? entry_size : 0;
if (user_buffers_[index].get() &&
user_buffers_[index]->PreRead(eof, offset, &buf_len)) {
// Complete the operation locally.
buf_len = user_buffers_[index]->Read(offset, buf, buf_len);
ReportIOTime(kRead, start);
return buf_len;
}
address.set_value(entry_.Data()->data_addr[index]);
DCHECK(address.is_initialized());
if (!address.is_initialized())
return net::ERR_FAILED;
File* file = GetBackingFile(address, index);
if (!file)
return net::ERR_FAILED;
size_t file_offset = offset;
if (address.is_block_file()) {
DCHECK_LE(offset + buf_len, kMaxBlockSize);
file_offset += address.start_block() * address.BlockSize() +
kBlockHeaderSize;
}
SyncCallback* io_callback = NULL;
if (callback) {
io_callback = new SyncCallback(this, buf, callback,
net::NetLog::TYPE_ENTRY_READ_DATA);
}
bool completed;
if (!file->Read(buf->data(), buf_len, file_offset, io_callback, &completed)) {
if (io_callback)
io_callback->Discard();
return net::ERR_FAILED;
}
if (io_callback && completed)
io_callback->Discard();
ReportIOTime(kRead, start);
return (completed || !callback) ? buf_len : net::ERR_IO_PENDING;
}
int EntryImpl::InternalWriteData(int index, int offset, net::IOBuffer* buf,
int buf_len, CompletionCallback* callback,
bool truncate) {
DCHECK(node_.Data()->dirty || read_only_);
DVLOG(2) << "Write to " << index << " at " << offset << " : " << buf_len;
if (index < 0 || index >= kNumStreams)
return net::ERR_INVALID_ARGUMENT;
if (offset < 0 || buf_len < 0)
return net::ERR_INVALID_ARGUMENT;
int max_file_size = backend_->MaxFileSize();
// offset or buf_len could be negative numbers.
if (offset > max_file_size || buf_len > max_file_size ||
offset + buf_len > max_file_size) {
int size = offset + buf_len;
if (size <= max_file_size)
size = kint32max;
backend_->TooMuchStorageRequested(size);
return net::ERR_FAILED;
}
TimeTicks start = TimeTicks::Now();
// Read the size at this point (it may change inside prepare).
int entry_size = entry_.Data()->data_size[index];
bool extending = entry_size < offset + buf_len;
truncate = truncate && entry_size > offset + buf_len;
Trace("To PrepareTarget 0x%x", entry_.address().value());
if (!PrepareTarget(index, offset, buf_len, truncate))
return net::ERR_FAILED;
Trace("From PrepareTarget 0x%x", entry_.address().value());
if (extending || truncate)
UpdateSize(index, entry_size, offset + buf_len);
UpdateRank(true);
backend_->OnEvent(Stats::WRITE_DATA);
backend_->OnWrite(buf_len);
if (user_buffers_[index].get()) {
// Complete the operation locally.
user_buffers_[index]->Write(offset, buf, buf_len);
ReportIOTime(kWrite, start);
return buf_len;
}
Addr address(entry_.Data()->data_addr[index]);
if (offset + buf_len == 0) {
if (truncate) {
DCHECK(!address.is_initialized());
}
return 0;
}
File* file = GetBackingFile(address, index);
if (!file)
return net::ERR_FAILED;
size_t file_offset = offset;
if (address.is_block_file()) {
DCHECK_LE(offset + buf_len, kMaxBlockSize);
file_offset += address.start_block() * address.BlockSize() +
kBlockHeaderSize;
} else if (truncate || (extending && !buf_len)) {
if (!file->SetLength(offset + buf_len))
return net::ERR_FAILED;
}
if (!buf_len)
return 0;
SyncCallback* io_callback = NULL;
if (callback) {
io_callback = new SyncCallback(this, buf, callback,
net::NetLog::TYPE_ENTRY_WRITE_DATA);
}
bool completed;
if (!file->Write(buf->data(), buf_len, file_offset, io_callback,
&completed)) {
if (io_callback)
io_callback->Discard();
return net::ERR_FAILED;
}
if (io_callback && completed)
io_callback->Discard();
ReportIOTime(kWrite, start);
return (completed || !callback) ? buf_len : net::ERR_IO_PENDING;
}
// ------------------------------------------------------------------------
bool EntryImpl::CreateDataBlock(int index, int size) {
DCHECK(index >= 0 && index < kNumStreams);
Addr address(entry_.Data()->data_addr[index]);
if (!CreateBlock(size, &address))
return false;
entry_.Data()->data_addr[index] = address.value();
entry_.Store();
return true;
}
bool EntryImpl::CreateBlock(int size, Addr* address) {
DCHECK(!address->is_initialized());
FileType file_type = Addr::RequiredFileType(size);
if (EXTERNAL == file_type) {
if (size > backend_->MaxFileSize())
return false;
if (!backend_->CreateExternalFile(address))
return false;
} else {
int num_blocks = (size + Addr::BlockSizeForFileType(file_type) - 1) /
Addr::BlockSizeForFileType(file_type);
if (!backend_->CreateBlock(file_type, num_blocks, address))
return false;
}
return true;
}
// Note that this method may end up modifying a block file so upon return the
// involved block will be free, and could be reused for something else. If there
// is a crash after that point (and maybe before returning to the caller), the
// entry will be left dirty... and at some point it will be discarded; it is
// important that the entry doesn't keep a reference to this address, or we'll
// end up deleting the contents of |address| once again.
void EntryImpl::DeleteData(Addr address, int index) {
if (!address.is_initialized())
return;
if (address.is_separate_file()) {
int failure = !DeleteCacheFile(backend_->GetFileName(address));
CACHE_UMA(COUNTS, "DeleteFailed", 0, failure);
if (failure) {
LOG(ERROR) << "Failed to delete " <<
backend_->GetFileName(address).value() << " from the cache.";
}
if (files_[index])
files_[index] = NULL; // Releases the object.
} else {
backend_->DeleteBlock(address, true);
}
}
void EntryImpl::UpdateRank(bool modified) {
if (!doomed_) {
// Everything is handled by the backend.
backend_->UpdateRank(this, modified);
return;
}
Time current = Time::Now();
node_.Data()->last_used = current.ToInternalValue();
if (modified)
node_.Data()->last_modified = current.ToInternalValue();
}
File* EntryImpl::GetBackingFile(Addr address, int index) {
File* file;
if (address.is_separate_file())
file = GetExternalFile(address, index);
else
file = backend_->File(address);
return file;
}
File* EntryImpl::GetExternalFile(Addr address, int index) {
DCHECK(index >= 0 && index <= kKeyFileIndex);
if (!files_[index].get()) {
// For a key file, use mixed mode IO.
scoped_refptr<File> file(new File(kKeyFileIndex == index));
if (file->Init(backend_->GetFileName(address)))
files_[index].swap(file);
}
return files_[index].get();
}
// We keep a memory buffer for everything that ends up stored on a block file
// (because we don't know yet the final data size), and for some of the data
// that end up on external files. This function will initialize that memory
// buffer and / or the files needed to store the data.
//
// In general, a buffer may overlap data already stored on disk, and in that
// case, the contents of the buffer are the most accurate. It may also extend
// the file, but we don't want to read from disk just to keep the buffer up to
// date. This means that as soon as there is a chance to get confused about what
// is the most recent version of some part of a file, we'll flush the buffer and
// reuse it for the new data. Keep in mind that the normal use pattern is quite
// simple (write sequentially from the beginning), so we optimize for handling
// that case.
bool EntryImpl::PrepareTarget(int index, int offset, int buf_len,
bool truncate) {
if (truncate)
return HandleTruncation(index, offset, buf_len);
if (!offset && !buf_len)
return true;
Addr address(entry_.Data()->data_addr[index]);
if (address.is_initialized()) {
if (address.is_block_file() && !MoveToLocalBuffer(index))
return false;
if (!user_buffers_[index].get() && offset < kMaxBlockSize) {
// We are about to create a buffer for the first 16KB, make sure that we
// preserve existing data.
if (!CopyToLocalBuffer(index))
return false;
}
}
if (!user_buffers_[index].get())
user_buffers_[index].reset(new UserBuffer(backend_));
return PrepareBuffer(index, offset, buf_len);
}
// We get to this function with some data already stored. If there is a
// truncation that results on data stored internally, we'll explicitly
// handle the case here.
bool EntryImpl::HandleTruncation(int index, int offset, int buf_len) {
Addr address(entry_.Data()->data_addr[index]);
int current_size = entry_.Data()->data_size[index];
int new_size = offset + buf_len;
if (!new_size) {
// This is by far the most common scenario.
backend_->ModifyStorageSize(current_size - unreported_size_[index], 0);
entry_.Data()->data_addr[index] = 0;
entry_.Data()->data_size[index] = 0;
unreported_size_[index] = 0;
entry_.Store();
DeleteData(address, index);
user_buffers_[index].reset();
return true;
}
// We never postpone truncating a file, if there is one, but we may postpone
// telling the backend about the size reduction.
if (user_buffers_[index].get()) {
DCHECK_GE(current_size, user_buffers_[index]->Start());
if (!address.is_initialized()) {
// There is no overlap between the buffer and disk.
if (new_size > user_buffers_[index]->Start()) {
// Just truncate our buffer.
DCHECK_LT(new_size, user_buffers_[index]->End());
user_buffers_[index]->Truncate(new_size);
return true;
}
// Just discard our buffer.
user_buffers_[index]->Reset();
return PrepareBuffer(index, offset, buf_len);
}
// There is some overlap or we need to extend the file before the
// truncation.
if (offset > user_buffers_[index]->Start())
user_buffers_[index]->Truncate(new_size);
UpdateSize(index, current_size, new_size);
if (!Flush(index, 0))
return false;
user_buffers_[index].reset();
}
// We have data somewhere, and it is not in a buffer.
DCHECK(!user_buffers_[index].get());
DCHECK(address.is_initialized());
if (new_size > kMaxBlockSize)
return true; // Let the operation go directly to disk.
return ImportSeparateFile(index, offset + buf_len);
}
bool EntryImpl::CopyToLocalBuffer(int index) {
Addr address(entry_.Data()->data_addr[index]);
DCHECK(!user_buffers_[index].get());
DCHECK(address.is_initialized());
int len = std::min(entry_.Data()->data_size[index], kMaxBlockSize);
user_buffers_[index].reset(new UserBuffer(backend_));
user_buffers_[index]->Write(len, NULL, 0);
File* file = GetBackingFile(address, index);
int offset = 0;
if (address.is_block_file())
offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
if (!file ||
!file->Read(user_buffers_[index]->Data(), len, offset, NULL, NULL)) {
user_buffers_[index].reset();
return false;
}
return true;
}
bool EntryImpl::MoveToLocalBuffer(int index) {
if (!CopyToLocalBuffer(index))
return false;
Addr address(entry_.Data()->data_addr[index]);
entry_.Data()->data_addr[index] = 0;
entry_.Store();
DeleteData(address, index);
// If we lose this entry we'll see it as zero sized.
int len = entry_.Data()->data_size[index];
backend_->ModifyStorageSize(len - unreported_size_[index], 0);
unreported_size_[index] = len;
return true;
}
bool EntryImpl::ImportSeparateFile(int index, int new_size) {
if (entry_.Data()->data_size[index] > new_size)
UpdateSize(index, entry_.Data()->data_size[index], new_size);
return MoveToLocalBuffer(index);
}
bool EntryImpl::PrepareBuffer(int index, int offset, int buf_len) {
DCHECK(user_buffers_[index].get());
if ((user_buffers_[index]->End() && offset > user_buffers_[index]->End()) ||
offset > entry_.Data()->data_size[index]) {
// We are about to extend the buffer or the file (with zeros), so make sure
// that we are not overwriting anything.
Addr address(entry_.Data()->data_addr[index]);
if (address.is_initialized() && address.is_separate_file()) {
if (!Flush(index, 0))
return false;
// There is an actual file already, and we don't want to keep track of
// its length so we let this operation go straight to disk.
// The only case when a buffer is allowed to extend the file (as in fill
// with zeros before the start) is when there is no file yet to extend.
user_buffers_[index].reset();
return true;
}
}
if (!user_buffers_[index]->PreWrite(offset, buf_len)) {
if (!Flush(index, offset + buf_len))
return false;
// Lets try again.
if (offset > user_buffers_[index]->End() ||
!user_buffers_[index]->PreWrite(offset, buf_len)) {
// We cannot complete the operation with a buffer.
DCHECK(!user_buffers_[index]->Size());
DCHECK(!user_buffers_[index]->Start());
user_buffers_[index].reset();
}
}
return true;
}
bool EntryImpl::Flush(int index, int min_len) {
Addr address(entry_.Data()->data_addr[index]);
DCHECK(user_buffers_[index].get());
DCHECK(!address.is_initialized() || address.is_separate_file());
DVLOG(3) << "Flush";
int size = std::max(entry_.Data()->data_size[index], min_len);
if (size && !address.is_initialized() && !CreateDataBlock(index, size))
return false;
if (!entry_.Data()->data_size[index]) {
DCHECK(!user_buffers_[index]->Size());
return true;
}
address.set_value(entry_.Data()->data_addr[index]);
int len = user_buffers_[index]->Size();
int offset = user_buffers_[index]->Start();
if (!len && !offset)
return true;
if (address.is_block_file()) {
DCHECK_EQ(len, entry_.Data()->data_size[index]);
DCHECK(!offset);
offset = address.start_block() * address.BlockSize() + kBlockHeaderSize;
}
File* file = GetBackingFile(address, index);
if (!file)
return false;
if (!file->Write(user_buffers_[index]->Data(), len, offset, NULL, NULL))
return false;
user_buffers_[index]->Reset();
return true;
}
void EntryImpl::UpdateSize(int index, int old_size, int new_size) {
if (entry_.Data()->data_size[index] == new_size)
return;
unreported_size_[index] += new_size - old_size;
entry_.Data()->data_size[index] = new_size;
entry_.set_modified();
}
int EntryImpl::InitSparseData() {
if (sparse_.get())
return net::OK;
// Use a local variable so that sparse_ never goes from 'valid' to NULL.
scoped_ptr<SparseControl> sparse(new SparseControl(this));
int result = sparse->Init();
if (net::OK == result)
sparse_.swap(sparse);
return result;
}
void EntryImpl::SetEntryFlags(uint32 flags) {
entry_.Data()->flags |= flags;
entry_.set_modified();
}
uint32 EntryImpl::GetEntryFlags() {
return entry_.Data()->flags;
}
void EntryImpl::GetData(int index, char** buffer, Addr* address) {
if (user_buffers_[index].get() && user_buffers_[index]->Size() &&
!user_buffers_[index]->Start()) {
// The data is already in memory, just copy it and we're done.
int data_len = entry_.Data()->data_size[index];
if (data_len <= user_buffers_[index]->Size()) {
DCHECK(!user_buffers_[index]->Start());
*buffer = new char[data_len];
memcpy(*buffer, user_buffers_[index]->Data(), data_len);
return;
}
}
// Bad news: we'd have to read the info from disk so instead we'll just tell
// the caller where to read from.
*buffer = NULL;
address->set_value(entry_.Data()->data_addr[index]);
if (address->is_initialized()) {
// Prevent us from deleting the block from the backing store.
backend_->ModifyStorageSize(entry_.Data()->data_size[index] -
unreported_size_[index], 0);
entry_.Data()->data_addr[index] = 0;
entry_.Data()->data_size[index] = 0;
}
}
void EntryImpl::Log(const char* msg) {
int dirty = 0;
if (node_.HasData()) {
dirty = node_.Data()->dirty;
}
Trace("%s 0x%p 0x%x 0x%x", msg, reinterpret_cast<void*>(this),
entry_.address().value(), node_.address().value());
Trace(" data: 0x%x 0x%x 0x%x", entry_.Data()->data_addr[0],
entry_.Data()->data_addr[1], entry_.Data()->long_key);
Trace(" doomed: %d 0x%x", doomed_, dirty);
}
} // namespace disk_cache