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1 // Copyright (c) 2013 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_TRACING_TRACING_CACHE_BACKEND_H_
6 #define NET_DISK_CACHE_TRACING_TRACING_CACHE_BACKEND_H_
7 
8 #include <map>
9 
10 #include "base/memory/scoped_ptr.h"
11 #include "base/memory/weak_ptr.h"
12 #include "net/disk_cache/blockfile/stats.h"
13 #include "net/disk_cache/disk_cache.h"
14 
15 namespace disk_cache {
16 
17 class EntryProxy;
18 
19 // The TracingCacheBackend implements the Cache Backend interface. It intercepts
20 // all backend operations from the IO thread and records the time from the start
21 // of the operation until the result is delivered.
22 class NET_EXPORT TracingCacheBackend : public Backend,
23     public base::SupportsWeakPtr<TracingCacheBackend> {
24  public:
25   explicit TracingCacheBackend(scoped_ptr<Backend> backend);
26 
27   virtual net::CacheType GetCacheType() const OVERRIDE;
28   virtual int32 GetEntryCount() const OVERRIDE;
29   virtual int OpenEntry(const std::string& key, Entry** entry,
30                         const CompletionCallback& callback) OVERRIDE;
31   virtual int CreateEntry(const std::string& key, Entry** entry,
32                           const CompletionCallback& callback) OVERRIDE;
33   virtual int DoomEntry(const std::string& key,
34                         const CompletionCallback& callback) OVERRIDE;
35   virtual int DoomAllEntries(const CompletionCallback& callback) OVERRIDE;
36   virtual int DoomEntriesBetween(base::Time initial_time,
37                                  base::Time end_time,
38                                  const CompletionCallback& callback) OVERRIDE;
39   virtual int DoomEntriesSince(base::Time initial_time,
40                                const CompletionCallback& callback) OVERRIDE;
41   virtual int OpenNextEntry(void** iter, Entry** next_entry,
42                             const CompletionCallback& callback) OVERRIDE;
43   virtual void EndEnumeration(void** iter) OVERRIDE;
44   virtual void GetStats(StatsItems* stats) OVERRIDE;
45   virtual void OnExternalCacheHit(const std::string& key) OVERRIDE;
46 
47  private:
48   friend class EntryProxy;
49   enum Operation {
50     OP_OPEN,
51     OP_CREATE,
52     OP_DOOM_ENTRY,
53     OP_READ,
54     OP_WRITE
55   };
56 
57   virtual ~TracingCacheBackend();
58 
59   EntryProxy* FindOrCreateEntryProxy(Entry* entry);
60 
61   void OnDeleteEntry(Entry* e);
62 
63   void RecordEvent(base::TimeTicks start_time, Operation op, std::string key,
64                    Entry* entry, int result);
65 
66   void BackendOpComplete(base::TimeTicks start_time, Operation op,
67                          std::string key, Entry** entry,
68                          const CompletionCallback& callback, int result);
69 
70   net::CompletionCallback BindCompletion(Operation op,
71                                          base::TimeTicks start_time,
72                                          const std::string& key, Entry **entry,
73                                          const net::CompletionCallback& cb);
74 
75   scoped_ptr<Backend> backend_;
76   typedef std::map<Entry*, EntryProxy*> EntryToProxyMap;
77   EntryToProxyMap open_entries_;
78 
79   DISALLOW_COPY_AND_ASSIGN(TracingCacheBackend);
80 };
81 
82 }  // namespace disk_cache
83 
84 #endif  // NET_DISK_CACHE_TRACING_TRACING_CACHE_BACKEND_H_
85