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_H_
6#define NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_H_
7
8#include "base/memory/scoped_ptr.h"
9#include "net/base/net_log.h"
10#include "net/disk_cache/blockfile/disk_format.h"
11#include "net/disk_cache/blockfile/storage_block-inl.h"
12#include "net/disk_cache/blockfile/storage_block.h"
13#include "net/disk_cache/disk_cache.h"
14
15namespace disk_cache {
16
17class BackendImpl;
18class InFlightBackendIO;
19class SparseControl;
20typedef StorageBlock<EntryStore> CacheEntryBlock;
21typedef StorageBlock<RankingsNode> CacheRankingsBlock;
22
23// This class implements the Entry interface. An object of this
24// class represents a single entry on the cache.
25class NET_EXPORT_PRIVATE EntryImpl
26    : public Entry,
27      public base::RefCounted<EntryImpl> {
28  friend class base::RefCounted<EntryImpl>;
29  friend class SparseControl;
30 public:
31  enum Operation {
32    kRead,
33    kWrite,
34    kSparseRead,
35    kSparseWrite,
36    kAsyncIO,
37    kReadAsync1,
38    kWriteAsync1
39  };
40
41  EntryImpl(BackendImpl* backend, Addr address, bool read_only);
42
43  // Background implementation of the Entry interface.
44  void DoomImpl();
45  int ReadDataImpl(int index, int offset, IOBuffer* buf, int buf_len,
46                   const CompletionCallback& callback);
47  int WriteDataImpl(int index, int offset, IOBuffer* buf, int buf_len,
48                    const CompletionCallback& callback, bool truncate);
49  int ReadSparseDataImpl(int64 offset, IOBuffer* buf, int buf_len,
50                         const CompletionCallback& callback);
51  int WriteSparseDataImpl(int64 offset, IOBuffer* buf, int buf_len,
52                          const CompletionCallback& callback);
53  int GetAvailableRangeImpl(int64 offset, int len, int64* start);
54  void CancelSparseIOImpl();
55  int ReadyForSparseIOImpl(const CompletionCallback& callback);
56
57  inline CacheEntryBlock* entry() {
58    return &entry_;
59  }
60
61  inline CacheRankingsBlock* rankings() {
62    return &node_;
63  }
64
65  uint32 GetHash();
66
67  // Performs the initialization of a EntryImpl that will be added to the
68  // cache.
69  bool CreateEntry(Addr node_address, const std::string& key, uint32 hash);
70
71  // Returns true if this entry matches the lookup arguments.
72  bool IsSameEntry(const std::string& key, uint32 hash);
73
74  // Permamently destroys this entry.
75  void InternalDoom();
76
77  // Deletes this entry from disk. If |everything| is false, only the user data
78  // will be removed, leaving the key and control data intact.
79  void DeleteEntryData(bool everything);
80
81  // Returns the address of the next entry on the list of entries with the same
82  // hash.
83  CacheAddr GetNextAddress();
84
85  // Sets the address of the next entry on the list of entries with the same
86  // hash.
87  void SetNextAddress(Addr address);
88
89  // Reloads the rankings node information.
90  bool LoadNodeAddress();
91
92  // Updates the stored data to reflect the run-time information for this entry.
93  // Returns false if the data could not be updated. The purpose of this method
94  // is to be able to detect entries that are currently in use.
95  bool Update();
96
97  bool dirty() {
98    return dirty_;
99  }
100
101  bool doomed() {
102    return doomed_;
103  }
104
105  // Marks this entry as dirty (in memory) if needed. This is intended only for
106  // entries that are being read from disk, to be called during loading.
107  void SetDirtyFlag(int32 current_id);
108
109  // Fixes this entry so it can be treated as valid (to delete it).
110  void SetPointerForInvalidEntry(int32 new_id);
111
112  // Returns true if this entry is so meesed up that not everything is going to
113  // be removed.
114  bool LeaveRankingsBehind();
115
116  // Returns false if the entry is clearly invalid.
117  bool SanityCheck();
118  bool DataSanityCheck();
119
120  // Attempts to make this entry reachable though the key.
121  void FixForDelete();
122
123  // Handle the pending asynchronous IO count.
124  void IncrementIoCount();
125  void DecrementIoCount();
126
127  // This entry is being returned to the user. It is always called from the
128  // primary thread (not the dedicated cache thread).
129  void OnEntryCreated(BackendImpl* backend);
130
131  // Set the access times for this entry. This method provides support for
132  // the upgrade tool.
133  void SetTimes(base::Time last_used, base::Time last_modified);
134
135  // Generates a histogram for the time spent working on this operation.
136  void ReportIOTime(Operation op, const base::TimeTicks& start);
137
138  // Logs a begin event and enables logging for the EntryImpl.  Will also cause
139  // an end event to be logged on destruction.  The EntryImpl must have its key
140  // initialized before this is called.  |created| is true if the Entry was
141  // created rather than opened.
142  void BeginLogging(net::NetLog* net_log, bool created);
143
144  const net::BoundNetLog& net_log() const;
145
146  // Returns the number of blocks needed to store an EntryStore.
147  static int NumBlocksForEntry(int key_size);
148
149  // Entry interface.
150  virtual void Doom() OVERRIDE;
151  virtual void Close() OVERRIDE;
152  virtual std::string GetKey() const OVERRIDE;
153  virtual base::Time GetLastUsed() const OVERRIDE;
154  virtual base::Time GetLastModified() const OVERRIDE;
155  virtual int32 GetDataSize(int index) const OVERRIDE;
156  virtual int ReadData(int index, int offset, IOBuffer* buf, int buf_len,
157                       const CompletionCallback& callback) OVERRIDE;
158  virtual int WriteData(int index, int offset, IOBuffer* buf, int buf_len,
159                        const CompletionCallback& callback,
160                        bool truncate) OVERRIDE;
161  virtual int ReadSparseData(int64 offset, IOBuffer* buf, int buf_len,
162                             const CompletionCallback& callback) OVERRIDE;
163  virtual int WriteSparseData(int64 offset, IOBuffer* buf, int buf_len,
164                              const CompletionCallback& callback) OVERRIDE;
165  virtual int GetAvailableRange(int64 offset, int len, int64* start,
166                                const CompletionCallback& callback) OVERRIDE;
167  virtual bool CouldBeSparse() const OVERRIDE;
168  virtual void CancelSparseIO() OVERRIDE;
169  virtual int ReadyForSparseIO(const CompletionCallback& callback) OVERRIDE;
170
171 private:
172  enum {
173     kNumStreams = 3
174  };
175  class UserBuffer;
176
177  virtual ~EntryImpl();
178
179  // Do all the work for ReadDataImpl and WriteDataImpl.  Implemented as
180  // separate functions to make logging of results simpler.
181  int InternalReadData(int index, int offset, IOBuffer* buf,
182                       int buf_len, const CompletionCallback& callback);
183  int InternalWriteData(int index, int offset, IOBuffer* buf, int buf_len,
184                        const CompletionCallback& callback, bool truncate);
185
186  // Initializes the storage for an internal or external data block.
187  bool CreateDataBlock(int index, int size);
188
189  // Initializes the storage for an internal or external generic block.
190  bool CreateBlock(int size, Addr* address);
191
192  // Deletes the data pointed by address, maybe backed by files_[index].
193  // Note that most likely the caller should delete (and store) the reference to
194  // |address| *before* calling this method because we don't want to have an
195  // entry using an address that is already free.
196  void DeleteData(Addr address, int index);
197
198  // Updates ranking information.
199  void UpdateRank(bool modified);
200
201  // Returns a pointer to the file that stores the given address.
202  File* GetBackingFile(Addr address, int index);
203
204  // Returns a pointer to the file that stores external data.
205  File* GetExternalFile(Addr address, int index);
206
207  // Prepares the target file or buffer for a write of buf_len bytes at the
208  // given offset.
209  bool PrepareTarget(int index, int offset, int buf_len, bool truncate);
210
211  // Adjusts the internal buffer and file handle for a write that truncates this
212  // stream.
213  bool HandleTruncation(int index, int offset, int buf_len);
214
215  // Copies data from disk to the internal buffer.
216  bool CopyToLocalBuffer(int index);
217
218  // Reads from a block data file to this object's memory buffer.
219  bool MoveToLocalBuffer(int index);
220
221  // Loads the external file to this object's memory buffer.
222  bool ImportSeparateFile(int index, int new_size);
223
224  // Makes sure that the internal buffer can handle the a write of |buf_len|
225  // bytes to |offset|.
226  bool PrepareBuffer(int index, int offset, int buf_len);
227
228  // Flushes the in-memory data to the backing storage. The data destination
229  // is determined based on the current data length and |min_len|.
230  bool Flush(int index, int min_len);
231
232  // Updates the size of a given data stream.
233  void UpdateSize(int index, int old_size, int new_size);
234
235  // Initializes the sparse control object. Returns a net error code.
236  int InitSparseData();
237
238  // Adds the provided |flags| to the current EntryFlags for this entry.
239  void SetEntryFlags(uint32 flags);
240
241  // Returns the current EntryFlags for this entry.
242  uint32 GetEntryFlags();
243
244  // Gets the data stored at the given index. If the information is in memory,
245  // a buffer will be allocated and the data will be copied to it (the caller
246  // can find out the size of the buffer before making this call). Otherwise,
247  // the cache address of the data will be returned, and that address will be
248  // removed from the regular book keeping of this entry so the caller is
249  // responsible for deleting the block (or file) from the backing store at some
250  // point; there is no need to report any storage-size change, only to do the
251  // actual cleanup.
252  void GetData(int index, char** buffer, Addr* address);
253
254  // Logs this entry to the internal trace buffer.
255  void Log(const char* msg);
256
257  CacheEntryBlock entry_;     // Key related information for this entry.
258  CacheRankingsBlock node_;   // Rankings related information for this entry.
259  base::WeakPtr<BackendImpl> backend_;  // Back pointer to the cache.
260  base::WeakPtr<InFlightBackendIO> background_queue_;  // In-progress queue.
261  scoped_ptr<UserBuffer> user_buffers_[kNumStreams];  // Stores user data.
262  // Files to store external user data and key.
263  scoped_refptr<File> files_[kNumStreams + 1];
264  mutable std::string key_;           // Copy of the key.
265  int unreported_size_[kNumStreams];  // Bytes not reported yet to the backend.
266  bool doomed_;               // True if this entry was removed from the cache.
267  bool read_only_;            // True if not yet writing.
268  bool dirty_;                // True if we detected that this is a dirty entry.
269  scoped_ptr<SparseControl> sparse_;  // Support for sparse entries.
270
271  net::BoundNetLog net_log_;
272
273  DISALLOW_COPY_AND_ASSIGN(EntryImpl);
274};
275
276}  // namespace disk_cache
277
278#endif  // NET_DISK_CACHE_BLOCKFILE_ENTRY_IMPL_H_
279