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      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 EXTENSIONS_COMMON_FEATURE_SWITCH_H_
      6 #define EXTENSIONS_COMMON_FEATURE_SWITCH_H_
      7 
      8 #include <string>
      9 
     10 #include "base/basictypes.h"
     11 
     12 namespace base {
     13 class CommandLine;
     14 }
     15 
     16 namespace extensions {
     17 
     18 // A switch that can turn a feature on or off. Typically controlled via
     19 // command-line switches but can be overridden, e.g., for testing.
     20 class FeatureSwitch {
     21  public:
     22   static FeatureSwitch* easy_off_store_install();
     23   static FeatureSwitch* force_dev_mode_highlighting();
     24   static FeatureSwitch* global_commands();
     25   static FeatureSwitch* prompt_for_external_extensions();
     26   static FeatureSwitch* error_console();
     27   static FeatureSwitch* enable_override_bookmarks_ui();
     28   static FeatureSwitch* scripts_require_action();
     29 
     30   enum DefaultValue {
     31     DEFAULT_ENABLED,
     32     DEFAULT_DISABLED
     33   };
     34 
     35   enum OverrideValue {
     36     OVERRIDE_NONE,
     37     OVERRIDE_ENABLED,
     38     OVERRIDE_DISABLED
     39   };
     40 
     41   // A temporary override for the switch value.
     42   class ScopedOverride {
     43    public:
     44     ScopedOverride(FeatureSwitch* feature, bool override_value);
     45     ~ScopedOverride();
     46    private:
     47     FeatureSwitch* feature_;
     48     FeatureSwitch::OverrideValue previous_value_;
     49     DISALLOW_COPY_AND_ASSIGN(ScopedOverride);
     50   };
     51 
     52   // |switch_name| can be NULL, in which case the feature is controlled solely
     53   // by the default and override values.
     54   FeatureSwitch(const char* switch_name,
     55                 DefaultValue default_value);
     56   FeatureSwitch(const base::CommandLine* command_line,
     57                 const char* switch_name,
     58                 DefaultValue default_value);
     59 
     60   // Consider using ScopedOverride instead.
     61   void SetOverrideValue(OverrideValue value);
     62   OverrideValue GetOverrideValue() const;
     63 
     64   bool IsEnabled() const;
     65 
     66  private:
     67   void Init(const base::CommandLine* command_line,
     68             const char* switch_name,
     69             DefaultValue default_value);
     70 
     71   std::string GetLegacyEnableFlag() const;
     72   std::string GetLegacyDisableFlag() const;
     73 
     74   const base::CommandLine* command_line_;
     75   const char* switch_name_;
     76   bool default_value_;
     77   OverrideValue override_value_;
     78 
     79   DISALLOW_COPY_AND_ASSIGN(FeatureSwitch);
     80 };
     81 
     82 }  // namespace extensions
     83 
     84 #endif  // EXTENSIONS_COMMON_FEATURE_SWITCH_H_
     85