1 // Copyright (c) 2012 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 CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_ 6 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_ 7 8 #include <map> 9 #include <set> 10 #include <vector> 11 12 #include "base/atomic_sequence_num.h" 13 #include "base/basictypes.h" 14 #include "base/files/file_path.h" 15 #include "base/gtest_prod_util.h" 16 #include "base/memory/ref_counted.h" 17 #include "base/observer_list.h" 18 #include "base/time/time.h" 19 #include "content/common/content_export.h" 20 #include "url/gurl.h" 21 22 namespace base { 23 class FilePath; 24 class NullableString16; 25 class Time; 26 } 27 28 namespace quota { 29 class SpecialStoragePolicy; 30 } 31 32 namespace content { 33 34 class DOMStorageArea; 35 class DOMStorageNamespace; 36 class DOMStorageSession; 37 class DOMStorageTaskRunner; 38 class SessionStorageDatabase; 39 struct LocalStorageUsageInfo; 40 struct SessionStorageUsageInfo; 41 42 // The Context is the root of an object containment hierachy for 43 // Namespaces and Areas related to the owning profile. 44 // One instance is allocated in the main process for each profile, 45 // instance methods should be called serially in the background as 46 // determined by the task_runner. Specifcally not on chrome's non-blocking 47 // IO thread since these methods can result in blocking file io. 48 // 49 // In general terms, the DOMStorage object relationships are... 50 // Contexts (per-profile) own Namespaces which own Areas which share Maps. 51 // Hosts(per-renderer) refer to Namespaces and Areas open in its renderer. 52 // Sessions (per-tab) cause the creation and deletion of session Namespaces. 53 // 54 // Session Namespaces are cloned by initially making a shallow copy of 55 // all contained Areas, the shallow copies refer to the same refcounted Map, 56 // and does a deep copy-on-write if needed. 57 // 58 // Classes intended to be used by an embedder are DOMStorageContextImpl, 59 // DOMStorageHost, and DOMStorageSession. The other classes are for 60 // internal consumption. 61 class CONTENT_EXPORT DOMStorageContextImpl 62 : public base::RefCountedThreadSafe<DOMStorageContextImpl> { 63 public: 64 // An interface for observing Local and Session Storage events on the 65 // background thread. 66 class EventObserver { 67 public: 68 // |old_value| may be null on initial insert. 69 virtual void OnDOMStorageItemSet( 70 const DOMStorageArea* area, 71 const base::string16& key, 72 const base::string16& new_value, 73 const base::NullableString16& old_value, 74 const GURL& page_url) = 0; 75 virtual void OnDOMStorageItemRemoved( 76 const DOMStorageArea* area, 77 const base::string16& key, 78 const base::string16& old_value, 79 const GURL& page_url) = 0; 80 virtual void OnDOMStorageAreaCleared( 81 const DOMStorageArea* area, 82 const GURL& page_url) = 0; 83 84 protected: 85 virtual ~EventObserver() {} 86 }; 87 88 // |localstorage_directory| and |sessionstorage_directory| may be empty 89 // for incognito browser contexts. 90 DOMStorageContextImpl( 91 const base::FilePath& localstorage_directory, 92 const base::FilePath& sessionstorage_directory, 93 quota::SpecialStoragePolicy* special_storage_policy, 94 DOMStorageTaskRunner* task_runner); 95 96 // Returns the directory path for localStorage, or an empty directory, if 97 // there is no backing on disk. 98 const base::FilePath& localstorage_directory() { 99 return localstorage_directory_; 100 } 101 102 // Returns the directory path for sessionStorage, or an empty directory, if 103 // there is no backing on disk. 104 const base::FilePath& sessionstorage_directory() { 105 return sessionstorage_directory_; 106 } 107 108 DOMStorageTaskRunner* task_runner() const { return task_runner_.get(); } 109 DOMStorageNamespace* GetStorageNamespace(int64 namespace_id); 110 111 void GetLocalStorageUsage(std::vector<LocalStorageUsageInfo>* infos, 112 bool include_file_info); 113 void GetSessionStorageUsage(std::vector<SessionStorageUsageInfo>* infos); 114 void DeleteLocalStorage(const GURL& origin); 115 void DeleteSessionStorage(const SessionStorageUsageInfo& usage_info); 116 void PurgeMemory(); 117 118 // Used by content settings to alter the behavior around 119 // what data to keep and what data to discard at shutdown. 120 // The policy is not so straight forward to describe, see 121 // the implementation for details. 122 void SetForceKeepSessionState() { 123 force_keep_session_state_ = true; 124 } 125 126 // Called when the owning BrowserContext is ending. 127 // Schedules the commit of any unsaved changes and will delete 128 // and keep data on disk per the content settings and special storage 129 // policies. Contained areas and namespaces will stop functioning after 130 // this method has been called. 131 void Shutdown(); 132 133 // Methods to add, remove, and notify EventObservers. 134 void AddEventObserver(EventObserver* observer); 135 void RemoveEventObserver(EventObserver* observer); 136 void NotifyItemSet( 137 const DOMStorageArea* area, 138 const base::string16& key, 139 const base::string16& new_value, 140 const base::NullableString16& old_value, 141 const GURL& page_url); 142 void NotifyItemRemoved( 143 const DOMStorageArea* area, 144 const base::string16& key, 145 const base::string16& old_value, 146 const GURL& page_url); 147 void NotifyAreaCleared( 148 const DOMStorageArea* area, 149 const GURL& page_url); 150 151 // May be called on any thread. 152 int64 AllocateSessionId() { 153 return session_id_sequence_.GetNext(); 154 } 155 156 std::string AllocatePersistentSessionId(); 157 158 // Must be called on the background thread. 159 void CreateSessionNamespace(int64 namespace_id, 160 const std::string& persistent_namespace_id); 161 void DeleteSessionNamespace(int64 namespace_id, bool should_persist_data); 162 void CloneSessionNamespace(int64 existing_id, int64 new_id, 163 const std::string& new_persistent_id); 164 165 // Starts backing sessionStorage on disk. This function must be called right 166 // after DOMStorageContextImpl is created, before it's used. 167 void SetSaveSessionStorageOnDisk(); 168 169 // Deletes all namespaces which don't have an associated DOMStorageNamespace 170 // alive. This function is used for deleting possible leftover data after an 171 // unclean exit. 172 void StartScavengingUnusedSessionStorage(); 173 174 private: 175 friend class DOMStorageContextImplTest; 176 FRIEND_TEST_ALL_PREFIXES(DOMStorageContextImplTest, Basics); 177 friend class base::RefCountedThreadSafe<DOMStorageContextImpl>; 178 typedef std::map<int64, scoped_refptr<DOMStorageNamespace> > 179 StorageNamespaceMap; 180 181 ~DOMStorageContextImpl(); 182 183 void ClearSessionOnlyOrigins(); 184 185 // For scavenging unused sessionStorages. 186 void FindUnusedNamespaces(); 187 void FindUnusedNamespacesInCommitSequence( 188 const std::set<std::string>& namespace_ids_in_use, 189 const std::set<std::string>& protected_persistent_session_ids); 190 void DeleteNextUnusedNamespace(); 191 void DeleteNextUnusedNamespaceInCommitSequence(); 192 193 // Collection of namespaces keyed by id. 194 StorageNamespaceMap namespaces_; 195 196 // Where localstorage data is stored, maybe empty for the incognito use case. 197 base::FilePath localstorage_directory_; 198 199 // Where sessionstorage data is stored, maybe empty for the incognito use 200 // case. Always empty until the file-backed session storage feature is 201 // implemented. 202 base::FilePath sessionstorage_directory_; 203 204 // Used to schedule sequenced background tasks. 205 scoped_refptr<DOMStorageTaskRunner> task_runner_; 206 207 // List of objects observing local storage events. 208 ObserverList<EventObserver> event_observers_; 209 210 // We use a 32 bit identifier for per tab storage sessions. 211 // At a tab per second, this range is large enough for 68 years. 212 base::AtomicSequenceNumber session_id_sequence_; 213 214 bool is_shutdown_; 215 bool force_keep_session_state_; 216 scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy_; 217 scoped_refptr<SessionStorageDatabase> session_storage_database_; 218 219 // For cleaning up unused namespaces gradually. 220 bool scavenging_started_; 221 std::vector<std::string> deletable_persistent_namespace_ids_; 222 223 // Persistent namespace IDs to protect from gradual deletion (they will 224 // be needed for session restore). 225 std::set<std::string> protected_persistent_session_ids_; 226 227 // Mapping between persistent namespace IDs and namespace IDs for 228 // sessionStorage. 229 std::map<std::string, int64> persistent_namespace_id_to_namespace_id_; 230 }; 231 232 } // namespace content 233 234 #endif // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_CONTEXT_IMPL_H_ 235