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      1 // Copyright (c) 2011 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 STORAGE_COMMON_DATABASE_DATABASE_CONNECTIONS_H_
      6 #define STORAGE_COMMON_DATABASE_DATABASE_CONNECTIONS_H_
      7 
      8 #include <map>
      9 #include <string>
     10 #include <vector>
     11 
     12 #include "base/memory/ref_counted.h"
     13 #include "base/strings/string16.h"
     14 #include "base/synchronization/lock.h"
     15 #include "storage/common/storage_common_export.h"
     16 
     17 namespace base {
     18 class MessageLoopProxy;
     19 }
     20 
     21 namespace storage {
     22 
     23 class STORAGE_COMMON_EXPORT DatabaseConnections {
     24  public:
     25   DatabaseConnections();
     26   ~DatabaseConnections();
     27 
     28   bool IsEmpty() const;
     29   bool IsDatabaseOpened(const std::string& origin_identifier,
     30                         const base::string16& database_name) const;
     31   bool IsOriginUsed(const std::string& origin_identifier) const;
     32 
     33   // Returns true if this is the first connection.
     34   bool AddConnection(const std::string& origin_identifier,
     35                      const base::string16& database_name);
     36 
     37   // Returns true if the last connection was removed.
     38   bool RemoveConnection(const std::string& origin_identifier,
     39                         const base::string16& database_name);
     40 
     41   void RemoveAllConnections();
     42   void RemoveConnections(
     43       const DatabaseConnections& connections,
     44       std::vector<std::pair<std::string, base::string16> >* closed_dbs);
     45 
     46   // Database sizes can be kept only if IsDatabaseOpened returns true.
     47   int64 GetOpenDatabaseSize(const std::string& origin_identifier,
     48                             const base::string16& database_name) const;
     49   void SetOpenDatabaseSize(const std::string& origin_identifier,
     50                            const base::string16& database_name,
     51                            int64 size);
     52 
     53   // Returns a list of the connections, <origin_id, name>.
     54   void ListConnections(
     55       std::vector<std::pair<std::string, base::string16> > *list) const;
     56 
     57  private:
     58   // Mapping from name to <openCount, size>
     59   typedef std::map<base::string16, std::pair<int, int64> > DBConnections;
     60   typedef std::map<std::string, DBConnections> OriginConnections;
     61   mutable OriginConnections connections_;  // mutable for GetOpenDatabaseSize
     62 
     63   // Returns true if the last connection was removed.
     64   bool RemoveConnectionsHelper(const std::string& origin_identifier,
     65                                const base::string16& database_name,
     66                                int num_connections);
     67 };
     68 
     69 // A wrapper class that provides thread-safety and the
     70 // ability to wait until all connections have closed.
     71 // Intended for use in renderer processes.
     72 class STORAGE_COMMON_EXPORT DatabaseConnectionsWrapper
     73     : public base::RefCountedThreadSafe<DatabaseConnectionsWrapper> {
     74  public:
     75   DatabaseConnectionsWrapper();
     76 
     77   // The Wait and Has methods should only be called on the
     78   // main thread (the thread on which the wrapper is constructed).
     79   void WaitForAllDatabasesToClose();
     80   bool HasOpenConnections();
     81 
     82   // Add and Remove may be called on any thread.
     83   void AddOpenConnection(const std::string& origin_identifier,
     84                          const base::string16& database_name);
     85   void RemoveOpenConnection(const std::string& origin_identifier,
     86                             const base::string16& database_name);
     87  private:
     88   ~DatabaseConnectionsWrapper();
     89   friend class base::RefCountedThreadSafe<DatabaseConnectionsWrapper>;
     90 
     91   bool waiting_for_dbs_to_close_;
     92   base::Lock open_connections_lock_;
     93   DatabaseConnections open_connections_;
     94   scoped_refptr<base::MessageLoopProxy> main_thread_;
     95 };
     96 
     97 }  // namespace storage
     98 
     99 #endif  // STORAGE_COMMON_DATABASE_DATABASE_CONNECTIONS_H_
    100