chrome/browser/extensions/external_pref_loader.h

   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 CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_
   6 #define CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_
   7
   8 #include <string>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/scoped_observer.h"
  13 #include "base/values.h"
  14 #include "chrome/browser/extensions/external_loader.h"
  15 #include "chrome/browser/prefs/pref_service_syncable_observer.h"
  16 #include "chrome/browser/sync/profile_sync_service.h"
  17 #include "components/sync_driver/sync_service_observer.h"
  18
  19 class PrefServiceSyncable;
  20 class Profile;
  21
  22 namespace extensions {
  23
  24 // A specialization of the ExternalLoader that uses a json file to
  25 // look up which external extensions are registered.
  26 // Instances of this class are expected to be created and destroyed on the UI
  27 // thread and they are expecting public method calls from the UI thread.
  28 class ExternalPrefLoader : public ExternalLoader,
  29                            public PrefServiceSyncableObserver,
  30                            public sync_driver::SyncServiceObserver {
  31  public:
  32   enum Options {
  33     NONE = 0,
  34
  35     // Ensure that only root can force an external install by checking
  36     // that all components of the path to external extensions files are
  37     // owned by root and not writable by any non-root user.
  38     ENSURE_PATH_CONTROLLED_BY_ADMIN = 1 << 0,
  39
  40     // Delay external preference load. It delays default apps installation
  41     // to not overload the system on first time user login.
  42     DELAY_LOAD_UNTIL_PRIORITY_SYNC = 1 << 1,
  43   };
  44
  45   // |base_path_id| is the directory containing the external_extensions.json
  46   // file or the standalone extension manifest files. Relative file paths to
  47   // extension files are resolved relative to this path. |profile| is used to
  48   // wait priority sync if DELAY_LOAD_UNTIL_PRIORITY_SYNC set.
  49   ExternalPrefLoader(int base_path_id, Options options, Profile* profile);
  50
  51   const base::FilePath GetBaseCrxFilePath() override;
  52
  53  protected:
  54   ~ExternalPrefLoader() override;
  55
  56   void StartLoading() override;
  57   bool IsOptionSet(Options option) {
  58     return (options_ & option) != 0;
  59   }
  60
  61   // The resource id of the base path with the information about the json
  62   // file containing which extensions to load.
  63   const int base_path_id_;
  64
  65   const Options options_;
  66
  67  private:
  68   friend class base::RefCountedThreadSafe<ExternalLoader>;
  69
  70   // PrefServiceSyncableObserver:
  71   void OnIsSyncingChanged() override;
  72
  73   // sync_driver::SyncServiceObserver
  74   void OnStateChanged() override;
  75
  76   // If priority sync ready posts LoadOnFileThread and return true.
  77   bool PostLoadIfPrioritySyncReady();
  78
  79   // Post LoadOnFileThread and stop observing for sync service states.
  80   void PostLoadAndRemoveObservers();
  81
  82   // Actually searches for and loads candidate standalone extension preference
  83   // files in the path corresponding to |base_path_id|.
  84   // Must be called on the file thread.
  85   void LoadOnFileThread();
  86
  87   // Extracts the information contained in an external_extension.json file
  88   // regarding which extensions to install. |prefs| will be modified to
  89   // receive the extracted extension information.
  90   // Must be called from the File thread.
  91   void ReadExternalExtensionPrefFile(base::DictionaryValue* prefs);
  92
  93   // Extracts the information contained in standalone external extension
  94   // json files (<extension id>.json) regarding what external extensions
  95   // to install. |prefs| will be modified to receive the extracted extension
  96   // information.
  97   // Must be called from the File thread.
  98   void ReadStandaloneExtensionPrefFiles(base::DictionaryValue* prefs);
  99
 100   // The path (coresponding to |base_path_id_| containing the json files
 101   // describing which extensions to load.
 102   base::FilePath base_path_;
 103
 104   // Profile that loads these external prefs.
 105   // Needed for waiting for waiting priority sync.
 106   Profile* profile_;
 107
 108   // Used for registering observer for PrefServiceSyncable.
 109   ScopedObserver<PrefServiceSyncable, PrefServiceSyncableObserver>
 110       syncable_pref_observer_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(ExternalPrefLoader);
 113 };
 114
 115 // A simplified version of ExternalPrefLoader that loads the dictionary
 116 // from json data specified in a string.
 117 class ExternalTestingLoader : public ExternalLoader {
 118  public:
 119   ExternalTestingLoader(const std::string& json_data,
 120                         const base::FilePath& fake_base_path);
 121
 122   const base::FilePath GetBaseCrxFilePath() override;
 123
 124  protected:
 125   void StartLoading() override;
 126
 127  private:
 128   friend class base::RefCountedThreadSafe<ExternalLoader>;
 129
 130   ~ExternalTestingLoader() override;
 131
 132   base::FilePath fake_base_path_;
 133   scoped_ptr<base::DictionaryValue> testing_prefs_;
 134
 135   DISALLOW_COPY_AND_ASSIGN(ExternalTestingLoader);
 136 };
 137
 138 }  // namespace extensions
 139
 140 #endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_