extensions/browser/api/storage/settings_storage_quota_enforcer.h

   1 // Copyright 2014 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 EXTENSIONS_BROWSER_API_STORAGE_SETTINGS_STORAGE_QUOTA_ENFORCER_H_
   6 #define EXTENSIONS_BROWSER_API_STORAGE_SETTINGS_STORAGE_QUOTA_ENFORCER_H_
   7
   8 #include "base/compiler_specific.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "extensions/browser/value_store/value_store.h"
  11
  12 namespace extensions {
  13
  14 // Enforces total quota and a per-setting quota in bytes, and a maximum number
  15 // of setting keys, for a delegate storage area.
  16 class SettingsStorageQuotaEnforcer : public ValueStore {
  17  public:
  18   struct Limits {
  19     // The total quota in bytes.
  20     size_t quota_bytes;
  21
  22     // The quota for each individual item in bytes.
  23     size_t quota_bytes_per_item;
  24
  25     // The maximum number of items allowed.
  26     size_t max_items;
  27   };
  28
  29   SettingsStorageQuotaEnforcer(const Limits& limits, ValueStore* delegate);
  30
  31   ~SettingsStorageQuotaEnforcer() override;
  32
  33   // ValueStore implementation.
  34   size_t GetBytesInUse(const std::string& key) override;
  35   size_t GetBytesInUse(const std::vector<std::string>& keys) override;
  36   size_t GetBytesInUse() override;
  37   ReadResult Get(const std::string& key) override;
  38   ReadResult Get(const std::vector<std::string>& keys) override;
  39   ReadResult Get() override;
  40   WriteResult Set(WriteOptions options,
  41                   const std::string& key,
  42                   const base::Value& value) override;
  43   WriteResult Set(WriteOptions options,
  44                   const base::DictionaryValue& values) override;
  45   WriteResult Remove(const std::string& key) override;
  46   WriteResult Remove(const std::vector<std::string>& keys) override;
  47   WriteResult Clear() override;
  48   bool Restore() override;
  49   bool RestoreKey(const std::string& key) override;
  50
  51   ValueStore* get_delegate_for_test() { return delegate_.get(); }
  52
  53  private:
  54   // Calculate the current usage for the database.
  55   void CalculateUsage();
  56
  57   // Limits configuration.
  58   const Limits limits_;
  59
  60   // The delegate storage area.
  61   scoped_ptr<ValueStore> const delegate_;
  62
  63   // Total bytes in used by |delegate_|. Includes both key lengths and
  64   // JSON-encoded values.
  65   size_t used_total_;
  66
  67   // Map of item key to its size, including the key itself.
  68   std::map<std::string, size_t> used_per_setting_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(SettingsStorageQuotaEnforcer);
  71 };
  72
  73 }  // namespace extensions
  74
  75 #endif  // EXTENSIONS_BROWSER_API_STORAGE_SETTINGS_STORAGE_QUOTA_ENFORCER_H_