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 "chrome/browser/extensions/external_loader.h"
   9
  10 #include <string>
  11
  12 #include "base/compiler_specific.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/values.h"
  15
  16 namespace extensions {
  17
  18 // A specialization of the ExternalLoader that uses a json file to
  19 // look up which external extensions are registered.
  20 // Instances of this class are expected to be created and destroyed on the UI
  21 // thread and they are expecting public method calls from the UI thread.
  22 class ExternalPrefLoader : public ExternalLoader {
  23  public:
  24   enum Options {
  25     NONE = 0,
  26
  27     // Ensure that only root can force an external install by checking
  28     // that all components of the path to external extensions files are
  29     // owned by root and not writable by any non-root user.
  30     ENSURE_PATH_CONTROLLED_BY_ADMIN = 1 << 0
  31   };
  32
  33   // |base_path_id| is the directory containing the external_extensions.json
  34   // file or the standalone extension manifest files. Relative file paths to
  35   // extension files are resolved relative to this path.
  36   ExternalPrefLoader(int base_path_id, Options options);
  37
  38   virtual const base::FilePath GetBaseCrxFilePath() OVERRIDE;
  39
  40  protected:
  41   virtual ~ExternalPrefLoader() {}
  42
  43   virtual void StartLoading() OVERRIDE;
  44   bool IsOptionSet(Options option) {
  45     return (options_ & option) != 0;
  46   }
  47
  48   // The resource id of the base path with the information about the json
  49   // file containing which extensions to load.
  50   const int base_path_id_;
  51
  52   const Options options_;
  53
  54  private:
  55   friend class base::RefCountedThreadSafe<ExternalLoader>;
  56
  57   // Actually searches for and loads candidate standalone extension preference
  58   // files in the path corresponding to |base_path_id|.
  59   // Must be called on the file thread.
  60   void LoadOnFileThread();
  61
  62   // Extracts the information contained in an external_extension.json file
  63   // regarding which extensions to install. |prefs| will be modified to
  64   // receive the extracted extension information.
  65   // Must be called from the File thread.
  66   void ReadExternalExtensionPrefFile(base::DictionaryValue* prefs);
  67
  68   // Extracts the information contained in standalone external extension
  69   // json files (<extension id>.json) regarding what external extensions
  70   // to install. |prefs| will be modified to receive the extracted extension
  71   // information.
  72   // Must be called from the File thread.
  73   void ReadStandaloneExtensionPrefFiles(base::DictionaryValue* prefs);
  74
  75   // The path (coresponding to |base_path_id_| containing the json files
  76   // describing which extensions to load.
  77   base::FilePath base_path_;
  78
  79   DISALLOW_COPY_AND_ASSIGN(ExternalPrefLoader);
  80 };
  81
  82 // A simplified version of ExternalPrefLoader that loads the dictionary
  83 // from json data specified in a string.
  84 class ExternalTestingLoader : public ExternalLoader {
  85  public:
  86   ExternalTestingLoader(const std::string& json_data,
  87                         const base::FilePath& fake_base_path);
  88
  89   virtual const base::FilePath GetBaseCrxFilePath() OVERRIDE;
  90
  91  protected:
  92   virtual void StartLoading() OVERRIDE;
  93
  94  private:
  95   friend class base::RefCountedThreadSafe<ExternalLoader>;
  96
  97   virtual ~ExternalTestingLoader();
  98
  99   base::FilePath fake_base_path_;
 100   scoped_ptr<base::DictionaryValue> testing_prefs_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(ExternalTestingLoader);
 103 };
 104
 105 }  // namespace extensions
 106
 107 #endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_PREF_LOADER_H_