components/policy/core/common/policy_map.h

   1 // Copyright 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 COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_
   6 #define COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_
   7
   8 #include <map>
   9 #include <set>
  10 #include <string>
  11
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/values.h"
  14 #include "components/policy/core/common/external_data_fetcher.h"
  15 #include "components/policy/core/common/policy_types.h"
  16 #include "components/policy/policy_export.h"
  17
  18 namespace policy {
  19
  20 // A mapping of policy names to policy values for a given policy namespace.
  21 class POLICY_EXPORT PolicyMap {
  22  public:
  23   // Each policy maps to an Entry which keeps the policy value as well as other
  24   // relevant data about the policy.
  25   struct POLICY_EXPORT Entry {
  26     PolicyLevel level;
  27     PolicyScope scope;
  28     base::Value* value;
  29     ExternalDataFetcher* external_data_fetcher;
  30
  31     Entry();
  32
  33     // Deletes all members owned by |this|.
  34     void DeleteOwnedMembers();
  35
  36     // Returns a copy of |this|.
  37     scoped_ptr<Entry> DeepCopy() const;
  38
  39     // Returns true if |this| has higher priority than |other|.
  40     bool has_higher_priority_than(const Entry& other) const;
  41
  42     // Returns true if |this| equals |other|.
  43     bool Equals(const Entry& other) const;
  44   };
  45
  46   typedef std::map<std::string, Entry> PolicyMapType;
  47   typedef PolicyMapType::const_iterator const_iterator;
  48
  49   PolicyMap();
  50   virtual ~PolicyMap();
  51
  52   // Returns a weak reference to the entry currently stored for key |policy|,
  53   // or NULL if not found. Ownership is retained by the PolicyMap.
  54   const Entry* Get(const std::string& policy) const;
  55
  56   // Returns a weak reference to the value currently stored for key |policy|,
  57   // or NULL if not found. Ownership is retained by the PolicyMap.
  58   // This is equivalent to Get(policy)->value, when it doesn't return NULL.
  59   const base::Value* GetValue(const std::string& policy) const;
  60
  61   // Takes ownership of |value| and |external_data_fetcher|. Overwrites any
  62   // existing information stored in the map for the key |policy|.
  63   void Set(const std::string& policy,
  64            PolicyLevel level,
  65            PolicyScope scope,
  66            base::Value* value,
  67            ExternalDataFetcher* external_data_fetcher);
  68
  69   // Erase the given |policy|, if it exists in this map.
  70   void Erase(const std::string& policy);
  71
  72   // Swaps the internal representation of |this| with |other|.
  73   void Swap(PolicyMap* other);
  74
  75   // |this| becomes a copy of |other|. Any existing policies are dropped.
  76   void CopyFrom(const PolicyMap& other);
  77
  78   // Returns a copy of |this|.
  79   scoped_ptr<PolicyMap> DeepCopy() const;
  80
  81   // Merges policies from |other| into |this|. Existing policies are only
  82   // overridden by those in |other| if they have a higher priority, as defined
  83   // by Entry::has_higher_priority_than(). If a policy is contained in both
  84   // maps with the same priority, the current value in |this| is preserved.
  85   void MergeFrom(const PolicyMap& other);
  86
  87   // Loads the values in |policies| into this PolicyMap. All policies loaded
  88   // will have |level| and |scope| in their entries. Existing entries are
  89   // replaced.
  90   void LoadFrom(const base::DictionaryValue* policies,
  91                 PolicyLevel level,
  92                 PolicyScope scope);
  93
  94   // Compares this value map against |other| and stores all key names that have
  95   // different values or reference different external data in |differing_keys|.
  96   // This includes keys that are present only in one of the maps.
  97   // |differing_keys| is not cleared before the keys are added.
  98   void GetDifferingKeys(const PolicyMap& other,
  99                         std::set<std::string>* differing_keys) const;
 100
 101   // Removes all policies that don't have the specified |level|. This is a
 102   // temporary helper method, until mandatory and recommended levels are served
 103   // by a single provider.
 104   // TODO(joaodasilva): Remove this. http://crbug.com/108999
 105   void FilterLevel(PolicyLevel level);
 106
 107   bool Equals(const PolicyMap& other) const;
 108   bool empty() const;
 109   size_t size() const;
 110
 111   const_iterator begin() const;
 112   const_iterator end() const;
 113   void Clear();
 114
 115  private:
 116   // Helper function for Equals().
 117   static bool MapEntryEquals(const PolicyMapType::value_type& a,
 118                              const PolicyMapType::value_type& b);
 119
 120   PolicyMapType map_;
 121
 122   DISALLOW_COPY_AND_ASSIGN(PolicyMap);
 123 };
 124
 125 }  // namespace policy
 126
 127 #endif  // COMPONENTS_POLICY_CORE_COMMON_POLICY_MAP_H_