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      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_
    108