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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef NET_DISK_CACHE_MEM_ENTRY_IMPL_H__
#define NET_DISK_CACHE_MEM_ENTRY_IMPL_H__
#include "net/disk_cache/disk_cache.h"
namespace disk_cache {
class MemBackendImpl;
// This class implements the Entry interface for the memory-only cache. An
// object of this class represents a single entry on the cache.
class MemEntryImpl : public Entry {
public:
explicit MemEntryImpl(MemBackendImpl* backend);
// Entry interface.
virtual void Doom();
virtual void Close();
virtual std::string GetKey() const;
virtual Time GetLastUsed() const;
virtual Time GetLastModified() const;
virtual int32 GetDataSize(int index) const;
virtual int ReadData(int index, int offset, char* buf, int buf_len,
net::CompletionCallback* completion_callback);
virtual int WriteData(int index, int offset, const char* buf, int buf_len,
net::CompletionCallback* completion_callback,
bool truncate);
// Performs the initialization of a EntryImpl that will be added to the
// cache.
bool CreateEntry(const std::string& key);
// Permamently destroys this entry
void InternalDoom();
MemEntryImpl* next() const {
return next_;
}
MemEntryImpl* prev() const {
return prev_;
}
void set_next(MemEntryImpl* next) {
next_ = next;
}
void set_prev(MemEntryImpl* prev) {
prev_ = prev;
}
void Open();
bool InUse();
private:
~MemEntryImpl();
// Grows and cleans up the data buffer.
void PrepareTarget(int index, int offset, int buf_len);
// Updates ranking information.
void UpdateRank(bool modified);
std::string key_;
std::vector<char> data_[2]; // User data.
int32 data_size_[2];
int ref_count_;
MemEntryImpl* next_; // Pointers for the LRU list.
MemEntryImpl* prev_;
Time last_modified_; // LRU information.
Time last_used_;
MemBackendImpl* backend_; // Back pointer to the cache.
bool doomed_; // True if this entry was removed from the cache.
DISALLOW_EVIL_CONSTRUCTORS(MemEntryImpl);
};
} // namespace disk_cache
#endif // NET_DISK_CACHE_MEM_ENTRY_IMPL_H__
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