resolve incompatibilities between absl types and their std equivalents

Author: dgoffredo

src/datadog/collector_response.cpp

@@ -6,9 +6,9 @@ namespace tracing {
 std::string CollectorResponse::key(StringView service, StringView environment) {
   std::string result;
   result += "service:";
-  result += service;
+  append(result, service);
   result += ",env:";
-  result += environment;
+  append(result, environment);
   return result;
 }
 

src/datadog/curl.cpp

@@ -247,7 +247,7 @@ Expected<void> CurlImpl::post(const HTTPClient::URL &url,
   }
   log_on_error(curl_multi_wakeup(multi_handle_));
 
-  return std::nullopt;
+  return nullopt;
 } catch (CURLcode error) {
   return Error{Error::CURL_REQUEST_SETUP_FAILED, curl_easy_strerror(error)};
 }
@@ -445,7 +445,7 @@ Optional<StringView> CurlImpl::HeaderReader::lookup(StringView key) const {
 
   const auto found = response_headers_lower_->find(buffer_);
   if (found == response_headers_lower_->end()) {
-    return std::nullopt;
+    return nullopt;
   }
   return found->second;
 }

src/datadog/datadog_agent.cpp

@@ -25,7 +25,7 @@ const StringView traces_api_path = "/v0.4/traces";
 
 HTTPClient::URL traces_endpoint(const HTTPClient::URL& agent_url) {
   auto traces_url = agent_url;
-  traces_url.path += traces_api_path;
+  append(traces_url.path, traces_api_path);
   return traces_url;
 }
 
@@ -59,10 +59,10 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
         "Parsing the Datadog Agent's response to traces we sent it failed.  "
         "The response is expected to be a JSON object, but instead it's a JSON "
         "value with type \"";
-    message += type;
+    append(message, type);
     message += '\"';
     message += "\nError occurred for response body (begins on next line):\n";
-    message += body;
+    append(message, body);
     return message;
   }
 
@@ -78,14 +78,14 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
     message +=
         "Parsing the Datadog Agent's response to traces we sent it failed.  "
         "The \"";
-    message += sample_rates_property;
+    append(message, sample_rates_property);
     message +=
         "\" property of the response is expected to be a JSON object, but "
         "instead it's a JSON value with type \"";
-    message += type;
+    append(message, type);
     message += '\"';
     message += "\nError occurred for response body (begins on next line):\n";
-    message += body;
+    append(message, body);
     return message;
   }
 
@@ -99,10 +99,10 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
           "for the key \"";
       message += key;
       message += "\". Rate should be a number, but it's a \"";
-      message += type;
+      append(message, type);
       message += "\" instead.";
       message += "\nError occurred for response body (begins on next line):\n";
-      message += body;
+      append(message, body);
       return message;
     }
     auto maybe_rate = Rate::from(value);
@@ -115,7 +115,7 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
       message += "\": ";
       message += error->message;
       message += "\nError occurred for response body (begins on next line):\n";
-      message += body;
+      append(message, body);
       return message;
     }
     sample_rates.emplace(key, *maybe_rate);
@@ -128,7 +128,7 @@ std::variant<CollectorResponse, std::string> parse_agent_traces_response(
       "JSON error: ";
   message += error.what();
   message += "\nError occurred for response body (begins on next line):\n";
-  message += body;
+  append(message, body);
   return message;
 }
 
@@ -161,7 +161,7 @@ Expected<void> DatadogAgent::send(
   std::lock_guard<std::mutex> lock(mutex_);
   incoming_trace_chunks_.push_back(
       TraceChunk{std::move(spans), response_handler});
-  return std::nullopt;
+  return nullopt;
 }
 
 nlohmann::json DatadogAgent::config_json() const {

src/datadog/datadog_agent_config.cpp

@@ -18,7 +18,7 @@ Expected<HTTPClient::URL> DatadogAgentConfig::parse(StringView input) {
   if (after_scheme == input.end()) {
     std::string message;
     message += "Datadog Agent URL is missing the \"://\" separator: \"";
-    message += input;
+    append(message, input);
     message += '\"';
     return Error{Error::URL_MISSING_SEPARATOR, std::move(message)};
   }
@@ -31,13 +31,13 @@ Expected<HTTPClient::URL> DatadogAgentConfig::parse(StringView input) {
   if (found == std::end(supported)) {
     std::string message;
     message += "Unsupported URI scheme \"";
-    message += scheme;
+    append(message, scheme);
     message += "\" in Datadog Agent URL \"";
-    message += input;
+    append(message, input);
     message += "\". The following are supported:";
     for (const auto& supported_scheme : supported) {
       message += ' ';
-      message += supported_scheme;
+      append(message, supported_scheme);
     }
     return Error{Error::URL_UNSUPPORTED_SCHEME, std::move(message)};
   }
@@ -59,9 +59,9 @@ Expected<HTTPClient::URL> DatadogAgentConfig::parse(StringView input) {
           "Unix domain socket paths for Datadog Agent must be absolute, i.e. "
           "must begin with a "
           "\"/\". The path \"";
-      message += authority_and_path;
+      append(message, authority_and_path);
       message += "\" is not absolute. Error occurred for URL: \"";
-      message += input;
+      append(message, input);
       message += '\"';
       return Error{Error::URL_UNIX_DOMAIN_SOCKET_PATH_NOT_ABSOLUTE,
                    std::move(message)};
@@ -119,13 +119,13 @@ Expected<FinalizedDatadogAgentConfig> finalize_config(
 
   std::string configured_url = config.url;
   if (auto url_env = lookup(environment::DD_TRACE_AGENT_URL)) {
-    configured_url = *url_env;
+    assign(configured_url, *url_env);
   } else if (env_host || env_port) {
     configured_url.clear();
     configured_url += "http://";
-    configured_url += env_host.value_or("localhost");
+    append(configured_url, env_host.value_or("localhost"));
     configured_url += ':';
-    configured_url += env_port.value_or("8126");
+    append(configured_url, env_port.value_or("8126"));
   }
 
   auto url = config.parse(configured_url);

src/datadog/dict_reader.h

@@ -16,7 +16,7 @@ class DictReader {
  public:
   virtual ~DictReader() {}
 
-  // Return the value at the specified `key`, or return `std::nullopt` if there
+  // Return the value at the specified `key`, or return `nullopt` if there
   // is no value at `key`.
   virtual Optional<StringView> lookup(StringView key) const = 0;
 

src/datadog/environment.cpp

@@ -14,7 +14,7 @@ Optional<StringView> lookup(Variable variable) {
   const char *name = variable_names[variable];
   const char *value = std::getenv(name);
   if (!value) {
-    return std::nullopt;
+    return nullopt;
   }
   return StringView{value};
 }

src/datadog/expected.h

@@ -2,7 +2,7 @@
 
 // This component provides a class template, `Expected<T>`, that is either an
 // instance of `T` or an instance of `Error`.  `Expected<void>` is either
-// `std::nullopt` or an instance of `Error`.
+// `nullopt` or an instance of `Error`.
 //
 // `Expected` is inspired by, but incompatible with, C++23's `std::expected`.
 //

src/datadog/msgpack.cpp

@@ -24,7 +24,7 @@ std::string make_overflow_message(StringView type, std::size_t actual,
                                   std::size_t max) {
   std::string message;
   message += "Cannot msgpack encode ";
-  message += type;
+  append(message, type);
   message += " of size ";
   message += std::to_string(actual);
   message += ", which exceeds the protocol maximum of ";

src/datadog/net_util.cpp

@@ -12,7 +12,7 @@ namespace tracing {
 Optional<std::string> get_hostname() {
   char buffer[256];
   if (::gethostname(buffer, sizeof buffer)) {
-    return std::nullopt;
+    return nullopt;
   }
   return buffer;
 }

src/datadog/optional.h

@@ -39,9 +39,11 @@ namespace tracing {
 #ifdef DD_USE_ABSEIL_FOR_ENVOY
 template <typename Value>
 using Optional = absl::optional<Value>;
+inline constexpr auto nullopt = absl::nullopt;
 #else
 template <typename Value>
 using Optional = std::optional<Value>;
+inline constexpr auto nullopt = std::nullopt;
 #endif  // defined DD_USE_ABSEIL_FOR_ENVOY
 
 }  // namespace tracing