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29 
30 #ifndef MOZC_SESSION_GENERIC_STORAGE_MANAGER_H_
31 #define MOZC_SESSION_GENERIC_STORAGE_MANAGER_H_
32 
33 #include <memory>
34 
35 #include "base/port.h"
36 #include "protocol/commands.pb.h"
37 
38 namespace mozc {
39 
40 class GenericStorageInterface;
41 
42 // For unit test.
43 class GenericLruStorageProxy;
44 
45 namespace storage {
46 class LRUStorage;
47 }  // namespace storage
48 
49 // Override and set the subclass's instance to
50 // GenericStorageManager for unit test.
51 class GenericStorageManagerInterface {
52  public:
GenericStorageManagerInterface()53   GenericStorageManagerInterface() {}
~GenericStorageManagerInterface()54   virtual ~GenericStorageManagerInterface() {}
55   virtual GenericStorageInterface *GetStorage(
56      commands::GenericStorageEntry::StorageType storage_type) = 0;
57 };
58 
59 // Manages generic storages.
60 class GenericStorageManagerFactory {
61  public:
62   // Returns corresponding storage's instance.
63   // If no instance is available, NULL is returned.
64   static GenericStorageInterface *GetStorage(
65      commands::GenericStorageEntry::StorageType storage_type);
66   // For unit test.
67   static void SetGenericStorageManager(GenericStorageManagerInterface *manager);
68 
69  private:
70   DISALLOW_IMPLICIT_CONSTRUCTORS(GenericStorageManagerFactory);
71 };
72 
73 // Generic interface for storages.
74 // This class defines only the interfaces.
75 // Detailed behaviors depend on the subclass's
76 // backend.
77 class GenericStorageInterface {
78  public:
GenericStorageInterface()79   GenericStorageInterface() {}
~GenericStorageInterface()80   virtual ~GenericStorageInterface() {}
81 
82   // Inserts new entry.
83   // If something goes wrong, returns false.
84   // value should be terminated by '\0'.
85   virtual bool Insert(const string &key, const char *value) = 0;
86   // Looks up the value.
87   // If something goes wrong, returns NULL.
88   virtual const char *Lookup(const string &key) = 0;
89   // Lists all the values.
90   // If something goes wrong, returns false.
91   virtual bool GetAllValues(std::vector<string> *values) = 0;
92   // Clears all the entries.
93   virtual bool Clear() = 0;
94 };
95 
96 // Storage class of which backend is LRUStorage.
97 class GenericLruStorage : public GenericStorageInterface {
98  public:
99   GenericLruStorage(
100       const char *file_name, size_t value_size, size_t size, uint32 seed);
101   virtual ~GenericLruStorage();
102 
103   // If the storage has |key|, this method overwrites
104   // the old value.
105   // If the entiry's size is over GetSize(),
106   // the oldest value is disposed.
107   virtual bool Insert(const string &key, const char *value);
108 
109   virtual const char *Lookup(const string &key);
110 
111   // The order is new to old.
112   virtual bool GetAllValues(std::vector<string> *values);
113 
114   virtual bool Clear();
115 
116  protected:
117   // Opens the storage if not opened yet.
118   // If something goes wrong, returns false.
119   bool EnsureStorage();
120 
121  private:
122   friend class GenericLruStorageProxy;
123   std::unique_ptr<mozc::storage::LRUStorage> lru_storage_;
124   const string file_name_;
125   const size_t value_size_;
126   const size_t size_;
127   const uint32 seed_;
128   // Temporary buffer to insert a value into this storage.
129   std::unique_ptr<char[]> value_buffer_;
130 
131   DISALLOW_COPY_AND_ASSIGN(GenericLruStorage);
132 };
133 
134 }  // namespace mozc
135 
136 #endif  // MOZC_SESSION_GENERIC_STORAGE_MANAGER_H_
137