Disk cache v3 ref2

net/disk_cache/v3/entry_impl_v3.h

 // 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_ENTRY_IMPL_H_
-#define NET_DISK_CACHE_ENTRY_IMPL_H_
+#ifndef NET_DISK_CACHE_V3_ENTRY_IMPL_V3_H_
+#define NET_DISK_CACHE_V3_ENTRY_IMPL_V3_H_
+
+#include <queue>
+#include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "net/base/net_log.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/storage_block.h"
-#include "net/disk_cache/storage_block-inl.h"
+#include "net/disk_cache/v3/disk_format_v3.h"
 
 namespace disk_cache {
 
-class BackendImpl;
-class InFlightBackendIO;
-class SparseControl;
+class BackendImplV3;
+class SparseControlV3;
+
+//typedef StorageBlock<EntryRecord> CacheEntryBlockV3;//?
+//typedef StorageBlock<ShortEntryRecord> CacheShortEntryBlock;
 
 // This class implements the Entry interface. An object of this
 // class represents a single entry on the cache.
-class NET_EXPORT_PRIVATE EntryImpl
+class NET_EXPORT_PRIVATE EntryImplV3
     : public Entry,
-      public base::RefCounted<EntryImpl> {
-  friend class base::RefCounted<EntryImpl>;
-  friend class SparseControl;
+      public base::RefCounted<EntryImplV3> {
+  friend class base::RefCounted<EntryImplV3>;
+  friend class SparseControlV3;
  public:
   enum Operation {
     kRead,
     kWrite,
     kSparseRead,
     kSparseWrite,
     kAsyncIO,
     kReadAsync1,
     kWriteAsync1
   };
 
-  EntryImpl(BackendImpl* backend, Addr address, bool read_only);
+  EntryImplV3(BackendImplV3* backend, Addr address, bool read_only);
+  EntryImplV3(BackendImplV3* backend, Addr address, const std::string& key,
+              scoped_ptr<EntryRecord> record);
+  EntryImplV3(BackendImplV3* backend, Addr address, const std::string& key,
+              scoped_ptr<ShortEntryRecord> record);
 
-  // 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);
+  // Performs the initialization of a EntryImplV3 that will be added to the
+  // cache.
+  void CreateEntry(const std::string& key, uint32 hash,
+                   ShortEntryRecord* old_info);
+  void OnOpenEntry();
 
-  // Performs the initialization of a EntryImpl that will be added to the
-  // cache.
-  bool CreateEntry(Addr node_address, const std::string& key, uint32 hash);
+  scoped_ptr<ShortEntryRecord> GetShortEntryRecord();
 
-  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();
 
-  bool dirty() {
-    return dirty_;
-  }
-
-  bool doomed() {
-    return doomed_;
-  }
-
   // Returns false if the entry is clearly invalid.
   bool SanityCheck();
   bool DataSanityCheck();
+  static bool BasicSanityCheck(const EntryRecord& record);
+  static bool DeletedSanityCheck(const ShortEntryRecord& record);
 
   // 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 EntryImpl.  Will also cause
-  // an end event to be logged on destruction.  The EntryImpl must have its key
+  // 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;
 
+  void NotifyDestructionForTest(const CompletionCallback& callback);
+
   // 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();
+  enum OperationAction {
+    PENDING_READ,
+    PENDING_WRITE,
+    PENDING_FLUSH,
+    PENDING_CLEANUP,
+    PENDING_DONE
+  };
+  struct PendingOperation {
+    OperationAction action;
+    int index;
+    int offset;
+    scoped_refptr<IOBuffer> buf;
+    int buf_len;
+    CompletionCallback callback;
+    bool truncate;
+  };
+  typedef std::queue<PendingOperation> PendingOperations;
+
+  virtual ~EntryImplV3();
+
+  void Cleanup();
+
+  void WriteKey();
 
   // 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,
+  int ReadDataImpl(int index, int offset, IOBuffer* buf,
+                       int buf_len, PendingOperation* operation,
+                       const CompletionCallback& callback);
+  int WriteDataImpl(int index, int offset, IOBuffer* buf, int buf_len,
+                        PendingOperation* operation,
                         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].
+  // Deletes the data pointed by address.
   // 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);
+  void DeleteData(Addr address);
 
   // 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);
+  // Deletes this entry from disk.
+  bool DeleteEntryData();
 
   // 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);
+  int 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);
+  int 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);
+  bool IsSimpleWrite(int index, int offset, int buf_len);
+  int HandleOldData(int index, int offset, int buf_len);
 
   // 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);
+  int 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);
+  int 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();
+  void WriteEntryData();
 
   // Adds the provided |flags| to the current EntryFlags for this entry.
   void SetEntryFlags(uint32 flags);
 
   // Returns the current EntryFlags for this entry.
   uint32 GetEntryFlags();
 
+  void OnEntryModified();
+
+  int GetAdjustedSize(int index, int real_size) const;
+
   // 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);
+  void GetData(int index, scoped_refptr<IOBuffer>* 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);
 
-  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.
+  void OnIOComplete(int result);
+
+  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.
   // Files to store external user data and key.
-  scoped_refptr<File> files_[kNumStreams + 1];
+  //scoped_refptr<File> files_[kNumStreams + 1];
   mutable std::string key_;           // Copy of the key.
+  Addr address_;
   int unreported_size_[kNumStreams];  // Bytes not reported yet to the backend.
+  int num_handles_;           // References held by "real" users.
   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.
+  bool read_only_;
+  bool dirty_;                // True if there is something to write.
+  bool modified_;
+  scoped_ptr<SparseControlV3> sparse_;  // Support for sparse entries.
+  PendingOperations pending_operations_;
+  CompletionCallback callback_;
+  CompletionCallback destruction_callback_;
 
   net::BoundNetLog net_log_;
 
-  DISALLOW_COPY_AND_ASSIGN(EntryImpl);
+  DISALLOW_COPY_AND_ASSIGN(EntryImplV3);
 };
 
 }  // namespace disk_cache
 
-#endif  // NET_DISK_CACHE_ENTRY_IMPL_H_
+#endif  // NET_DISK_CACHE_V3_ENTRY_IMPL_V3_H_