storage/common/database/database_connections.h

   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 SingleThreadTaskRunner;
  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::SingleThreadTaskRunner> main_thread_;
  95 };
  96
  97 }  // namespace storage
  98
  99 #endif  // STORAGE_COMMON_DATABASE_DATABASE_CONNECTIONS_H_