// 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_H_
#define NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_H_
#include "base/memory/scoped_ptr.h"
#include "net/base/net_log.h"
#include "net/disk_cache/blockfile/disk_format.h"
#include "net/disk_cache/blockfile/storage_block-inl.h"
#include "net/disk_cache/blockfile/storage_block.h"
#include "net/disk_cache/disk_cache.h"
namespace disk_cache {
class BackendImpl;
class InFlightBackendIO;
class SparseControl;
typedef StorageBlock<EntryStore> CacheEntryBlock;
typedef StorageBlock<RankingsNode> CacheRankingsBlock;
// This class implements the Entry interface. An object of this
// class represents a single entry on the cache.
class NET_EXPORT_PRIVATE EntryImpl
: public Entry,
public base::RefCounted<EntryImpl> {
friend class base::RefCounted<EntryImpl>;
friend class SparseControl;
public:
enum Operation {
kRead,
kWrite,
kSparseRead,
kSparseWrite,
kAsyncIO,
kReadAsync1,
kWriteAsync1
};
EntryImpl(BackendImpl* backend, Addr address, bool read_only);
// Background implementation of the Entry interface.
void DoomImpl();
int ReadDataImpl(int index, int offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback);
int WriteDataImpl(int index, int offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback, bool truncate);
int ReadSparseDataImpl(int64 offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback);
int WriteSparseDataImpl(int64 offset, IOBuffer* buf, int buf_len,
const CompletionCallback& callback);
int GetAvailableRangeImpl(int64 offset, int len, int64* start);
void CancelSparseIOImpl();
int ReadyForSparseIOImpl(const CompletionCallback& callback);
inline CacheEntryBlock* entry() {
return &entry_;
}
inline CacheRankingsBlock* rankings() {
return &node_;
}
uint32 GetHash();
// Performs the initialization of a EntryImpl that will be added to the
// cache.
bool CreateEntry(Addr node_address, const std::string& key, uint32 hash);
// Returns true if this entry matches the lookup arguments.
bool IsSameEntry(const std::string& key, uint32 hash);
// Permamently destroys this entry.
void InternalDoom();
// 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);
// Returns the address of the next entry on the list of entries with the same
// hash.
CacheAddr GetNextAddress();
// Sets the address of the next entry on the list of entries with the same
// hash.
void SetNextAddress(Addr address);
// Reloads the rankings node information.
bool LoadNodeAddress();
// Updates the stored data to reflect the run-time information for this entry.
// Returns false if the data could not be updated. The purpose of this method
// is to be able to detect entries that are currently in use.
bool Update();
bool dirty() {
return dirty_;
}
bool doomed() {
return doomed_;
}
// Marks this entry as dirty (in memory) if needed. This is intended only for
// entries that are being read from disk, to be called during loading.
void SetDirtyFlag(int32 current_id);
// Fixes this entry so it can be treated as valid (to delete it).
void SetPointerForInvalidEntry(int32 new_id);
// Returns true if this entry is so meesed up that not everything is going to
// be removed.
bool LeaveRankingsBehind();
// Returns false if the entry is clearly invalid.
bool SanityCheck();
bool DataSanityCheck();
// Attempts to make this entry reachable though the key.
void FixForDelete();
// Handle the pending asynchronous IO count.
void IncrementIoCount();
void DecrementIoCount();
// This entry is being returned to the user. It is always called from the
// primary thread (not the dedicated cache thread).
void OnEntryCreated(BackendImpl* backend);
// 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);
// Generates a histogram for the time spent working on this operation.
void ReportIOTime(Operation op, const base::TimeTicks& start);
// Logs a begin event and enables logging for the EntryImpl. Will also cause
// an end event to be logged on destruction. The EntryImpl 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;
// Returns the number of blocks needed to store an EntryStore.
static int NumBlocksForEntry(int key_size);
// 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 ~EntryImpl();
// 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);
// Returns a pointer to the file that stores the given address.
File* GetBackingFile(Addr address, int index);
// Returns a pointer to the file that stores external data.
File* GetExternalFile(Addr address, int index);
// 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);
// Logs this entry to the internal trace buffer.
void Log(const char* msg);
CacheEntryBlock entry_; // Key related information for this entry.
CacheRankingsBlock node_; // Rankings related information for this entry.
base::WeakPtr<BackendImpl> backend_; // Back pointer to the cache.
base::WeakPtr<InFlightBackendIO> background_queue_; // In-progress queue.
scoped_ptr<UserBuffer> user_buffers_[kNumStreams]; // Stores user data.
// Files to store external user data and key.
scoped_refptr<File> files_[kNumStreams + 1];
mutable std::string key_; // Copy of the key.
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_; // True if not yet writing.
bool dirty_; // True if we detected that this is a dirty entry.
scoped_ptr<SparseControl> sparse_; // Support for sparse entries.
net::BoundNetLog net_log_;
DISALLOW_COPY_AND_ASSIGN(EntryImpl);
};
} // namespace disk_cache
#endif // NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_H_