base/scoped_add_feature_flags.cc

   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 #include "base/scoped_add_feature_flags.h"
   6
   7 #include "base/base_switches.h"
   8 #include "base/command_line.h"
   9 #include "base/containers/contains.h"
  10 #include "base/strings/strcat.h"
  11 #include "base/strings/string_util.h"
  12
  13 namespace base {
  14
  15 ScopedAddFeatureFlags::ScopedAddFeatureFlags(CommandLine* command_line)
  16     : command_line_(command_line) {
  17   std::string enabled_features =
  18       command_line->GetSwitchValueASCII(switches::kEnableFeatures);
  19   std::string disabled_features =
  20       command_line->GetSwitchValueASCII(switches::kDisableFeatures);
  21   for (const StringPiece& feature :
  22        FeatureList::SplitFeatureListString(enabled_features)) {
  23     enabled_features_.emplace_back(feature);
  24   }
  25   for (const StringPiece& feature :
  26        FeatureList::SplitFeatureListString(disabled_features)) {
  27     disabled_features_.emplace_back(feature);
  28   }
  29 }
  30
  31 ScopedAddFeatureFlags::~ScopedAddFeatureFlags() {
  32   command_line_->RemoveSwitch(switches::kEnableFeatures);
  33   command_line_->AppendSwitchASCII(switches::kEnableFeatures,
  34                                    JoinString(enabled_features_, ","));
  35   command_line_->RemoveSwitch(switches::kDisableFeatures);
  36   command_line_->AppendSwitchASCII(switches::kDisableFeatures,
  37                                    JoinString(disabled_features_, ","));
  38 }
  39
  40 void ScopedAddFeatureFlags::EnableIfNotSet(const Feature& feature) {
  41   AddFeatureIfNotSet(feature, /*suffix=*/"", /*enable=*/true);
  42 }
  43
  44 void ScopedAddFeatureFlags::EnableIfNotSetWithParameter(const Feature& feature,
  45                                                         StringPiece name,
  46                                                         StringPiece value) {
  47   std::string suffix = StrCat({":", name, "/", value});
  48   AddFeatureIfNotSet(feature, suffix, true /* enable */);
  49 }
  50
  51 void ScopedAddFeatureFlags::DisableIfNotSet(const Feature& feature) {
  52   AddFeatureIfNotSet(feature, /*suffix=*/"", /*enable=*/false);
  53 }
  54
  55 bool ScopedAddFeatureFlags::IsEnabled(const Feature& feature) {
  56   return IsEnabledWithParameter(feature, /*parameter_name=*/"",
  57                                 /*parameter_value=*/"");
  58 }
  59
  60 bool ScopedAddFeatureFlags::IsEnabledWithParameter(
  61     const Feature& feature,
  62     StringPiece parameter_name,
  63     StringPiece parameter_value) {
  64   std::string feature_name = feature.name;
  65   if (!parameter_name.empty()) {
  66     StrAppend(&feature_name, {":", parameter_name, "/", parameter_value});
  67   }
  68   if (Contains(disabled_features_, feature_name))
  69     return false;
  70   if (Contains(enabled_features_, feature_name))
  71     return true;
  72   return feature.default_state == FEATURE_ENABLED_BY_DEFAULT;
  73 }
  74
  75 void ScopedAddFeatureFlags::AddFeatureIfNotSet(const Feature& feature,
  76                                                StringPiece suffix,
  77                                                bool enable) {
  78   std::string feature_name = StrCat({feature.name, suffix});
  79   if (Contains(enabled_features_, feature_name) ||
  80       Contains(disabled_features_, feature_name)) {
  81     return;
  82   }
  83   if (enable) {
  84     enabled_features_.emplace_back(feature_name);
  85   } else {
  86     disabled_features_.emplace_back(feature_name);
  87   }
  88 }
  89
  90 }  // namespace base