Added flag reader interface

PiperOrigin-RevId: 514551069

Package.swift

@@ -417,6 +417,7 @@ let package = Package(
         "internal/platform/implementation/BUILD",
         "internal/platform/BUILD",
         "internal/analytics/BUILD",
+        "internal/flags/BUILD",
         "internal/network/BUILD",
         "internal/base/BUILD",
         // tests

internal/flags/BUILD

@@ -0,0 +1,26 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+licenses(["notice"])
+
+cc_library(
+    name = "flag_reader",
+    hdrs = [
+        "default_flag_reader.h",
+        "flag.h",
+        "flag_reader.h",
+    ],
+    visibility = ["//:__subpackages__"],
+    deps = ["@com_google_absl//absl/strings"],
+)

internal/flags/default_flag_reader.h

@@ -0,0 +1,55 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_NEARBY_INTERNAL_FLAGS_DEFAULT_FLAG_READER_H_
+#define THIRD_PARTY_NEARBY_INTERNAL_FLAGS_DEFAULT_FLAG_READER_H_
+
+#include <cstdint>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "internal/flags/flag_reader.h"
+
+namespace nearby {
+namespace flags {
+
+class DefaultFlagReader : public FlagReader {
+ public:
+  ~DefaultFlagReader() override = default;
+
+  // Returns the default bool value of the flag.
+  bool GetBoolFlag(const Flag<bool>& flag) override {
+    return flag.default_value();
+  }
+
+  // Returns the default int64_t value of the flag.
+  int64_t GetInt64Flag(const Flag<int64_t>& flag) override {
+    return flag.default_value();
+  }
+
+  // Returns the default double value of the flag.
+  double GetDoubleFlag(const Flag<double>& flag) override {
+    return flag.default_value();
+  }
+
+  // Returns the default string value of the flag.
+  std::string GetStringFlag(const Flag<absl::string_view>& flag) override {
+    return std::string(flag.default_value());
+  }
+};
+
+}  // namespace flags
+}  // namespace nearby
+
+#endif  // THIRD_PARTY_NEARBY_INTERNAL_FLAGS_DEFAULT_FLAG_READER_H_

internal/flags/flag.h

@@ -0,0 +1,45 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_H_
+#define THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_H_
+
+#include "absl/strings/string_view.h"
+
+namespace nearby {
+namespace flags {
+
+template <typename T>
+class Flag {
+ public:
+  constexpr Flag(const absl::string_view config_package_name,
+                 const absl::string_view name, const T default_value)
+      : config_package_name_(config_package_name),
+        name_(name),
+        default_value_(default_value) {}
+
+  absl::string_view config_package_name() const { return config_package_name_; }
+  absl::string_view name() const { return name_; }
+  T default_value() const { return default_value_; }
+
+ private:
+  const absl::string_view config_package_name_;
+  const absl::string_view name_;
+  const T default_value_;
+};
+
+}  // namespace flags
+}  // namespace nearby
+
+#endif  // THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_H_

internal/flags/flag_reader.h

@@ -0,0 +1,51 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_READER_H_
+#define THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_READER_H_
+
+#include <cstdint>
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "internal/flags/flag.h"
+
+namespace nearby {
+namespace flags {
+
+// Allows caller to get flag values form backend system.
+// The caller could implement flexiable control on Nearby SDK in granularity,
+// such as feature, configuration etc. Default value will be returned if no
+// flag-supported backend.
+class FlagReader {
+ public:
+  virtual ~FlagReader() = default;
+
+  // Reads flag with boolean value.
+  virtual bool GetBoolFlag(const Flag<bool>& flag) = 0;
+
+  // Reads flag with int64_t value.
+  virtual int64_t GetInt64Flag(const Flag<int64_t>& flag) = 0;
+
+  // Reads flag with double value.
+  virtual double GetDoubleFlag(const Flag<double>& flag) = 0;
+
+  // Reads flag with string value.
+  virtual std::string GetStringFlag(const Flag<absl::string_view>& flag) = 0;
+};
+
+}  // namespace flags
+}  // namespace nearby
+
+#endif  // THIRD_PARTY_NEARBY_INTERNAL_FLAGS_FLAG_READER_H_