1 // Copyright 2019 The Chromium Authors 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 BASE_SCOPED_ADD_FEATURE_FLAGS_H_ 6 #define BASE_SCOPED_ADD_FEATURE_FLAGS_H_ 7 8 #include <string> 9 #include <string_view> 10 #include <vector> 11 12 #include "base/base_export.h" 13 #include "base/feature_list.h" 14 #include "base/memory/raw_ptr.h" 15 16 namespace base { 17 18 class CommandLine; 19 20 // Helper class to enable and disable features if they are not already set in 21 // the command line. It reads the command line on construction, allows user to 22 // enable and disable features during its lifetime, and writes the modified 23 // --enable-features=... and --disable-features=... flags back to the command 24 // line on destruction. 25 class BASE_EXPORT ScopedAddFeatureFlags { 26 public: 27 explicit ScopedAddFeatureFlags(CommandLine* command_line); 28 29 ScopedAddFeatureFlags(const ScopedAddFeatureFlags&) = delete; 30 ScopedAddFeatureFlags& operator=(const ScopedAddFeatureFlags&) = delete; 31 32 ~ScopedAddFeatureFlags(); 33 34 // Any existing (user set) enable/disable takes precedence. 35 void EnableIfNotSet(const Feature& feature); 36 void DisableIfNotSet(const Feature& feature); 37 void EnableIfNotSetWithParameter(const Feature& feature, 38 std::string_view name, 39 std::string_view value); 40 41 // Check if the feature is enabled from command line or functions above 42 bool IsEnabled(const Feature& feature); 43 44 // Check if the feature with the given parameter name and value is enabled 45 // from command line or functions above. An empty parameter name means that we 46 // are checking if the feature is enabled without any parameter. 47 bool IsEnabledWithParameter(const Feature& feature, 48 std::string_view parameter_name, 49 std::string_view parameter_value); 50 51 private: 52 void AddFeatureIfNotSet(const Feature& feature, 53 std::string_view suffix, 54 bool enable); 55 56 const raw_ptr<CommandLine> command_line_; 57 std::vector<std::string> enabled_features_; 58 std::vector<std::string> disabled_features_; 59 }; 60 61 } // namespace base 62 63 #endif // BASE_SCOPED_ADD_FEATURE_FLAGS_H_ 64