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/*
* 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 <cstdint>
#include <cstdio>
#include <map>
#include <optional>
#include <string>
#include <type_traits>
#include <variant>
#include <vector>
#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 std::optional<std::vector<T>>* attribute) {
return true;
}
// Any other type is not.
template <typename T>
bool operator()(const std::optional<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) {
if constexpr (std::is_same_v<T, bool>) {
return BoolToString(value);
}
return absl::StrCat(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], std::size(buf), "%.16g",
static_cast<double>(value));
RTC_DCHECK_LE(len, std::ssize(buf));
return std::string(&buf[0], len);
}
// Vector attributes.
template <typename T>
std::string operator()(const std::optional<std::vector<T>>* attribute) {
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 std::optional<std::map<std::string, T>>* attribute) {
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 std::optional<T>* attribute) {
return ValueToString(attribute->value());
}
};
struct VisitIsEqual {
template <typename T>
bool operator()(const std::optional<T>* attribute) {
if (!other.holds_alternative<T>()) {
return false;
}
return *attribute == 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 std::visit([](const auto* attr) { return attr->has_value(); },
attribute_);
}
bool Attribute::is_sequence() const {
return std::visit(VisitIsSequence(), attribute_);
}
bool Attribute::is_string() const {
return std::holds_alternative<const std::optional<std::string>*>(attribute_);
}
std::string Attribute::ToString() const {
if (!has_value()) {
return "null";
}
return std::visit(VisitToString(), attribute_);
}
bool Attribute::operator==(const Attribute& other) const {
return std::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
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