1 files changed, 172 insertions, 0 deletions
diff --git a/third_party/libwebrtc/stats/attribute.cc b/third_party/libwebrtc/stats/attribute.cc
new file mode 100644
index 0000000000..fab948b1bd
--- /dev/null
+++ b/third_party/libwebrtc/stats/attribute.cc
@@ -0,0 +1,172 @@
+/*
+ *  Copyright 2024 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "api/stats/attribute.h"
+
+#include <string>
+
+#include "absl/types/variant.h"
+#include "rtc_base/arraysize.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/string_encode.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+
+namespace {
+
+struct VisitIsSequence {
+  // Any type of vector is a sequence.
+  template <typename T>
+  bool operator()(const RTCStatsMember<std::vector<T>>* attribute) {
+    return true;
+  }
+  // Any other type is not.
+  template <typename T>
+  bool operator()(const RTCStatsMember<T>* attribute) {
+    return false;
+  }
+};
+
+// Converts the attribute to string in a JSON-compatible way.
+struct VisitToString {
+  template <typename T,
+            typename std::enable_if_t<
+                std::is_same_v<T, int32_t> || std::is_same_v<T, uint32_t> ||
+                    std::is_same_v<T, bool> || std::is_same_v<T, std::string>,
+                bool> = true>
+  std::string ValueToString(const T& value) {
+    return rtc::ToString(value);
+  }
+  // Convert 64-bit integers to doubles before converting to string because JSON
+  // represents all numbers as floating points with ~15 digits of precision.
+  template <typename T,
+            typename std::enable_if_t<std::is_same_v<T, int64_t> ||
+                                          std::is_same_v<T, uint64_t> ||
+                                          std::is_same_v<T, double>,
+                                      bool> = true>
+  std::string ValueToString(const T& value) {
+    char buf[32];
+    const int len = std::snprintf(&buf[0], arraysize(buf), "%.16g",
+                                  static_cast<double>(value));
+    RTC_DCHECK_LE(len, arraysize(buf));
+    return std::string(&buf[0], len);
+  }
+
+  // Vector attributes.
+  template <typename T>
+  std::string operator()(const RTCStatsMember<std::vector<T>>* attribute) {
+    rtc::StringBuilder sb;
+    sb << "[";
+    const char* separator = "";
+    constexpr bool element_is_string = std::is_same<T, std::string>::value;
+    for (const T& element : attribute->value()) {
+      sb << separator;
+      if (element_is_string) {
+        sb << "\"";
+      }
+      sb << ValueToString(element);
+      if (element_is_string) {
+        sb << "\"";
+      }
+      separator = ",";
+    }
+    sb << "]";
+    return sb.Release();
+  }
+  // Map attributes.
+  template <typename T>
+  std::string operator()(
+      const RTCStatsMember<std::map<std::string, T>>* attribute) {
+    rtc::StringBuilder sb;
+    sb << "{";
+    const char* separator = "";
+    constexpr bool element_is_string = std::is_same<T, std::string>::value;
+    for (const auto& pair : attribute->value()) {
+      sb << separator;
+      sb << "\"" << pair.first << "\":";
+      if (element_is_string) {
+        sb << "\"";
+      }
+      sb << ValueToString(pair.second);
+      if (element_is_string) {
+        sb << "\"";
+      }
+      separator = ",";
+    }
+    sb << "}";
+    return sb.Release();
+  }
+  // Simple attributes.
+  template <typename T>
+  std::string operator()(const RTCStatsMember<T>* attribute) {
+    return ValueToString(attribute->value());
+  }
+};
+
+struct VisitIsEqual {
+  template <typename T>
+  bool operator()(const RTCStatsMember<T>* attribute) {
+    if (!other.holds_alternative<T>()) {
+      return false;
+    }
+    absl::optional<T> attribute_as_optional =
+        attribute->has_value() ? absl::optional<T>(attribute->value())
+                               : absl::nullopt;
+    return attribute_as_optional == other.as_optional<T>();
+  }
+
+  const Attribute& other;
+};
+
+}  // namespace
+
+const char* Attribute::name() const {
+  return name_;
+}
+
+const Attribute::StatVariant& Attribute::as_variant() const {
+  return attribute_;
+}
+
+bool Attribute::has_value() const {
+  return absl::visit([](const auto* attr) { return attr->has_value(); },
+                     attribute_);
+}
+
+bool Attribute::is_sequence() const {
+  return absl::visit(VisitIsSequence(), attribute_);
+}
+
+bool Attribute::is_string() const {
+  return absl::holds_alternative<const RTCStatsMember<std::string>*>(
+      attribute_);
+}
+
+std::string Attribute::ToString() const {
+  if (!has_value()) {
+    return "null";
+  }
+  return absl::visit(VisitToString(), attribute_);
+}
+
+bool Attribute::operator==(const Attribute& other) const {
+  return absl::visit(VisitIsEqual{.other = other}, attribute_);
+}
+
+bool Attribute::operator!=(const Attribute& other) const {
+  return !(*this == other);
+}
+
+AttributeInit::AttributeInit(const char* name,
+                             const Attribute::StatVariant& variant)
+    : name(name), variant(variant) {}
+
+}  // namespace webrtc