net/disk_cache/blockfile/entry_impl_v3.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_
   6 #define NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "net/disk_cache/blockfile/disk_format_v3.h"
  12 #include "net/disk_cache/blockfile/storage_block.h"
  13 #include "net/disk_cache/disk_cache.h"
  14 #include "net/log/net_log.h"
  15
  16 namespace disk_cache {
  17
  18 class BackendImplV3;
  19 class SparseControlV3;
  20
  21 // This class implements the Entry interface. An object of this
  22 // class represents a single entry on the cache.
  23 class NET_EXPORT_PRIVATE EntryImplV3
  24     : public Entry,
  25       public base::RefCounted<EntryImplV3> {
  26   friend class base::RefCounted<EntryImplV3>;
  27   // friend class SparseControlV3;
  28  public:
  29   enum Operation {
  30     kRead,
  31     kWrite,
  32     kSparseRead,
  33     kSparseWrite,
  34     kAsyncIO,
  35     kReadAsync1,
  36     kWriteAsync1
  37   };
  38
  39   EntryImplV3(BackendImplV3* backend, Addr address, bool read_only);
  40
  41   // Performs the initialization of a EntryImplV3 that will be added to the
  42   // cache.
  43   bool CreateEntry(Addr node_address, const std::string& key, uint32 hash);
  44
  45   uint32 GetHash();
  46
  47   uint32 GetHash() const;
  48   Addr GetAddress() const;
  49   int GetReuseCounter() const;
  50   void SetReuseCounter(int count);
  51   int GetRefetchCounter() const;
  52   void SetRefetchCounter(int count);
  53
  54   // Returns true if this entry matches the lookup arguments.
  55   bool IsSameEntry(const std::string& key, uint32 hash);
  56
  57   // Permamently destroys this entry.
  58   void InternalDoom();
  59
  60   // Returns false if the entry is clearly invalid.
  61   bool SanityCheck();
  62   bool DataSanityCheck();
  63
  64   // Attempts to make this entry reachable though the key.
  65   void FixForDelete();
  66
  67   // Set the access times for this entry. This method provides support for
  68   // the upgrade tool.
  69   void SetTimes(base::Time last_used, base::Time last_modified);
  70
  71   // Logs a begin event and enables logging for the EntryImplV3. Will also cause
  72   // an end event to be logged on destruction. The EntryImplV3 must have its key
  73   // initialized before this is called. |created| is true if the Entry was
  74   // created rather than opened.
  75   void BeginLogging(net::NetLog* net_log, bool created);
  76
  77   const net::BoundNetLog& net_log() const;
  78
  79   // Entry interface.
  80   void Doom() override;
  81   void Close() override;
  82   std::string GetKey() const override;
  83   base::Time GetLastUsed() const override;
  84   base::Time GetLastModified() const override;
  85   int32 GetDataSize(int index) const override;
  86   int ReadData(int index,
  87                int offset,
  88                IOBuffer* buf,
  89                int buf_len,
  90                const CompletionCallback& callback) override;
  91   int WriteData(int index,
  92                 int offset,
  93                 IOBuffer* buf,
  94                 int buf_len,
  95                 const CompletionCallback& callback,
  96                 bool truncate) override;
  97   int ReadSparseData(int64 offset,
  98                      IOBuffer* buf,
  99                      int buf_len,
 100                      const CompletionCallback& callback) override;
 101   int WriteSparseData(int64 offset,
 102                       IOBuffer* buf,
 103                       int buf_len,
 104                       const CompletionCallback& callback) override;
 105   int GetAvailableRange(int64 offset,
 106                         int len,
 107                         int64* start,
 108                         const CompletionCallback& callback) override;
 109   bool CouldBeSparse() const override;
 110   void CancelSparseIO() override;
 111   int ReadyForSparseIO(const CompletionCallback& callback) override;
 112
 113  private:
 114   enum {
 115      kNumStreams = 3
 116   };
 117   class UserBuffer;
 118
 119   ~EntryImplV3() override;
 120
 121   // Do all the work for ReadDataImpl and WriteDataImpl.  Implemented as
 122   // separate functions to make logging of results simpler.
 123   int InternalReadData(int index, int offset, IOBuffer* buf,
 124                        int buf_len, const CompletionCallback& callback);
 125   int InternalWriteData(int index, int offset, IOBuffer* buf, int buf_len,
 126                         const CompletionCallback& callback, bool truncate);
 127
 128   // Initializes the storage for an internal or external data block.
 129   bool CreateDataBlock(int index, int size);
 130
 131   // Initializes the storage for an internal or external generic block.
 132   bool CreateBlock(int size, Addr* address);
 133
 134   // Deletes the data pointed by address, maybe backed by files_[index].
 135   // Note that most likely the caller should delete (and store) the reference to
 136   // |address| *before* calling this method because we don't want to have an
 137   // entry using an address that is already free.
 138   void DeleteData(Addr address, int index);
 139
 140   // Updates ranking information.
 141   void UpdateRank(bool modified);
 142
 143   // Deletes this entry from disk. If |everything| is false, only the user data
 144   // will be removed, leaving the key and control data intact.
 145   void DeleteEntryData(bool everything);
 146
 147   // Prepares the target file or buffer for a write of buf_len bytes at the
 148   // given offset.
 149   bool PrepareTarget(int index, int offset, int buf_len, bool truncate);
 150
 151   // Adjusts the internal buffer and file handle for a write that truncates this
 152   // stream.
 153   bool HandleTruncation(int index, int offset, int buf_len);
 154
 155   // Copies data from disk to the internal buffer.
 156   bool CopyToLocalBuffer(int index);
 157
 158   // Reads from a block data file to this object's memory buffer.
 159   bool MoveToLocalBuffer(int index);
 160
 161   // Loads the external file to this object's memory buffer.
 162   bool ImportSeparateFile(int index, int new_size);
 163
 164   // Makes sure that the internal buffer can handle the a write of |buf_len|
 165   // bytes to |offset|.
 166   bool PrepareBuffer(int index, int offset, int buf_len);
 167
 168   // Flushes the in-memory data to the backing storage. The data destination
 169   // is determined based on the current data length and |min_len|.
 170   bool Flush(int index, int min_len);
 171
 172   // Updates the size of a given data stream.
 173   void UpdateSize(int index, int old_size, int new_size);
 174
 175   // Initializes the sparse control object. Returns a net error code.
 176   int InitSparseData();
 177
 178   // Adds the provided |flags| to the current EntryFlags for this entry.
 179   void SetEntryFlags(uint32 flags);
 180
 181   // Returns the current EntryFlags for this entry.
 182   uint32 GetEntryFlags();
 183
 184   // Gets the data stored at the given index. If the information is in memory,
 185   // a buffer will be allocated and the data will be copied to it (the caller
 186   // can find out the size of the buffer before making this call). Otherwise,
 187   // the cache address of the data will be returned, and that address will be
 188   // removed from the regular book keeping of this entry so the caller is
 189   // responsible for deleting the block (or file) from the backing store at some
 190   // point; there is no need to report any storage-size change, only to do the
 191   // actual cleanup.
 192   void GetData(int index, char** buffer, Addr* address);
 193
 194   // Generates a histogram for the time spent working on this operation.
 195   void ReportIOTime(Operation op, const base::TimeTicks& start);
 196
 197   // Logs this entry to the internal trace buffer.
 198   void Log(const char* msg);
 199
 200   scoped_ptr<EntryRecord> entry_;  // Basic record for this entry.
 201   scoped_ptr<ShortEntryRecord> short_entry_;  // Valid for evicted entries.
 202   base::WeakPtr<BackendImplV3> backend_;  // Back pointer to the cache.
 203   scoped_ptr<UserBuffer> user_buffers_[kNumStreams];  // Stores user data.
 204   mutable std::string key_;           // Copy of the key.
 205   Addr address_;
 206   int unreported_size_[kNumStreams];  // Bytes not reported yet to the backend.
 207   bool doomed_;               // True if this entry was removed from the cache.
 208   bool read_only_;
 209   bool dirty_;                // True if there is something to write.
 210   bool modified_;
 211   // scoped_ptr<SparseControlV3> sparse_;  // Support for sparse entries.
 212
 213   net::BoundNetLog net_log_;
 214
 215   DISALLOW_COPY_AND_ASSIGN(EntryImplV3);
 216 };
 217
 218 }  // namespace disk_cache
 219
 220 #endif  // NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_V3_H_