// Copyright (c) 2012 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.
#ifndef NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_
#define NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_
#include <string>
#include "base/memory/scoped_ptr.h"
#include "net/base/net_log.h"
#include "net/disk_cache/blockfile/disk_format_v3.h"
#include "net/disk_cache/blockfile/storage_block.h"
#include "net/disk_cache/disk_cache.h"
namespace disk_cache {
class BackendImplV3;
class SparseControlV3;
// This class implements the Entry interface. An object of this
// class represents a single entry on the cache.
class NET_EXPORT_PRIVATE EntryImplV3
: public Entry,
public base::RefCounted<EntryImplV3> {
friend class base::RefCounted<EntryImplV3>;
// friend class SparseControlV3;
public:
enum Operation {
kRead,
kWrite,
kSparseRead,
kSparseWrite,
kAsyncIO,
kReadAsync1,
kWriteAsync1
};
EntryImplV3(BackendImplV3* backend, Addr address, bool read_only);
// Performs the initialization of a EntryImplV3 that will be added to the
// cache.
bool CreateEntry(Addr node_address, const std::string& key, uint32 hash);
uint32 GetHash();
uint32 GetHash() const;
Addr GetAddress() const;
int GetReuseCounter() const;
void SetReuseCounter(int count);
int GetRefetchCounter() const;
void SetRefetchCounter(int count);
// Returns true if this entry matches the lookup arguments.
bool IsSameEntry(const std::string& key, uint32 hash);
// Permamently destroys this entry.
void InternalDoom();
// Returns false if the entry is clearly invalid.
bool SanityCheck();
bool DataSanityCheck();
// Attempts to make this entry reachable though the key.
void FixForDelete();
// Set the access times for this entry. This method provides support for
// the upgrade tool.
void SetTimes(base::Time last_used, base::Time last_modified);
// Logs a begin event and enables logging for the EntryImplV3. Will also cause
// an end event to be logged on destruction. The EntryImplV3 must have its key
// initialized before this is called. |created| is true if the Entry was
// created rather than opened.
void BeginLogging(net::NetLog* net_log, bool created);
const net::BoundNetLog& net_log() const;
// Entry interface.
virtual void Doom() OVERRIDE;
virtual void Close() OVERRIDE;
virtual std::string GetKey() const OVERRIDE;
virtual base::Time GetLastUsed() const OVERRIDE;
virtual base::Time GetLastModified() const OVERRIDE;
virtual int32 GetDataSize(int index) const OVERRIDE;
virtual int ReadData(int index, int offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback) OVERRIDE;
virtual int WriteData(int index, int offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback,
bool truncate) OVERRIDE;
virtual int ReadSparseData(int64 offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback) OVERRIDE;
virtual int WriteSparseData(int64 offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback) OVERRIDE;
virtual int GetAvailableRange(int64 offset, int len, int64* start,
const CompletionCallback& callback) OVERRIDE;
virtual bool CouldBeSparse() const OVERRIDE;
virtual void CancelSparseIO() OVERRIDE;
virtual int ReadyForSparseIO(const CompletionCallback& callback) OVERRIDE;
private:
enum {
kNumStreams = 3
};
class UserBuffer;
virtual ~EntryImplV3();
// Do all the work for ReadDataImpl and WriteDataImpl. Implemented as
// separate functions to make logging of results simpler.
int InternalReadData(int index, int offset, IOBuffer* buf,
int buf_len, const CompletionCallback& callback);
int InternalWriteData(int index, int offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback, bool truncate);
// Initializes the storage for an internal or external data block.
bool CreateDataBlock(int index, int size);
// Initializes the storage for an internal or external generic block.
bool CreateBlock(int size, Addr* address);
// Deletes the data pointed by address, maybe backed by files_[index].
// Note that most likely the caller should delete (and store) the reference to
// |address| *before* calling this method because we don't want to have an
// entry using an address that is already free.
void DeleteData(Addr address, int index);
// Updates ranking information.
void UpdateRank(bool modified);
// Deletes this entry from disk. If |everything| is false, only the user data
// will be removed, leaving the key and control data intact.
void DeleteEntryData(bool everything);
// Prepares the target file or buffer for a write of buf_len bytes at the
// given offset.
bool PrepareTarget(int index, int offset, int buf_len, bool truncate);
// Adjusts the internal buffer and file handle for a write that truncates this
// stream.
bool HandleTruncation(int index, int offset, int buf_len);
// Copies data from disk to the internal buffer.
bool CopyToLocalBuffer(int index);
// Reads from a block data file to this object's memory buffer.
bool MoveToLocalBuffer(int index);
// Loads the external file to this object's memory buffer.
bool ImportSeparateFile(int index, int new_size);
// Makes sure that the internal buffer can handle the a write of |buf_len|
// bytes to |offset|.
bool PrepareBuffer(int index, int offset, int buf_len);
// Flushes the in-memory data to the backing storage. The data destination
// is determined based on the current data length and |min_len|.
bool Flush(int index, int min_len);
// Updates the size of a given data stream.
void UpdateSize(int index, int old_size, int new_size);
// Initializes the sparse control object. Returns a net error code.
int InitSparseData();
// Adds the provided |flags| to the current EntryFlags for this entry.
void SetEntryFlags(uint32 flags);
// Returns the current EntryFlags for this entry.
uint32 GetEntryFlags();
// Gets the data stored at the given index. If the information is in memory,
// a buffer will be allocated and the data will be copied to it (the caller
// can find out the size of the buffer before making this call). Otherwise,
// the cache address of the data will be returned, and that address will be
// removed from the regular book keeping of this entry so the caller is
// responsible for deleting the block (or file) from the backing store at some
// point; there is no need to report any storage-size change, only to do the
// actual cleanup.
void GetData(int index, char** buffer, Addr* address);
// Generates a histogram for the time spent working on this operation.
void ReportIOTime(Operation op, const base::TimeTicks& start);
// Logs this entry to the internal trace buffer.
void Log(const char* msg);
scoped_ptr<EntryRecord> entry_; // Basic record for this entry.
scoped_ptr<ShortEntryRecord> short_entry_; // Valid for evicted entries.
base::WeakPtr<BackendImplV3> backend_; // Back pointer to the cache.
scoped_ptr<UserBuffer> user_buffers_[kNumStreams]; // Stores user data.
mutable std::string key_; // Copy of the key.
Addr address_;
int unreported_size_[kNumStreams]; // Bytes not reported yet to the backend.
bool doomed_; // True if this entry was removed from the cache.
bool read_only_;
bool dirty_; // True if there is something to write.
bool modified_;
// scoped_ptr<SparseControlV3> sparse_; // Support for sparse entries.
net::BoundNetLog net_log_;
DISALLOW_COPY_AND_ASSIGN(EntryImplV3);
};
} // namespace disk_cache
#endif // NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_