field_trials_view.h (1906B)
1 /* 2 * Copyright 2019 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 #ifndef API_FIELD_TRIALS_VIEW_H_ 11 #define API_FIELD_TRIALS_VIEW_H_ 12 13 #include <memory> 14 #include <string> 15 16 #include "absl/strings/match.h" 17 #include "absl/strings/string_view.h" 18 #include "rtc_base/checks.h" 19 #include "rtc_base/system/rtc_export.h" 20 21 namespace webrtc { 22 23 // An interface that provides the means to access field trials. 24 // 25 // A FieldTrialsView is guaranteed to be immutable, 26 // 27 // Note that there are no guarantess that the meaning of a particular key-value 28 // mapping will be preserved over time and no announcements will be made if they 29 // are changed. It's up to the library user to ensure that the behavior does not 30 // break. 31 class RTC_EXPORT FieldTrialsView { 32 public: 33 virtual ~FieldTrialsView() = default; 34 35 // Returns the configured value for `key` or an empty string if the field 36 // trial isn't configured. 37 virtual std::string Lookup(absl::string_view key) const = 0; 38 39 bool IsEnabled(absl::string_view key) const { 40 return absl::StartsWith(Lookup(key), "Enabled"); 41 } 42 43 bool IsDisabled(absl::string_view key) const { 44 return absl::StartsWith(Lookup(key), "Disabled"); 45 } 46 47 // Create a copy of this view. 48 // 49 // This method can't be pure virtual, due to downstream projects 50 // but that is fine since they won't use the method...if they 51 // implement their own FieldTrialsView. 52 virtual std::unique_ptr<FieldTrialsView> CreateCopy() const { 53 RTC_CHECK_NOTREACHED(); 54 return nullptr; 55 } 56 }; 57 58 } // namespace webrtc 59 60 #endif // API_FIELD_TRIALS_VIEW_H_