Adding RTCErrorOr class to be used by ORTC APIs.

webrtc/api/rtcerror.cc

+/*
+ *  Copyright 2017 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 "webrtc/api/rtcerror.h"
+
+#include "webrtc/base/arraysize.h"
+
+namespace {
+
+static const char* const kRTCErrorTypeNames[] = {
+    "NONE",
+    "UNSUPPORTED_OPERATION",
+    "UNSUPPORTED_PARAMETER",
+    "INVALID_PARAMETER",
+    "INVALID_RANGE",
+    "SYNTAX_ERROR",
+    "INVALID_STATE",
+    "INVALID_MODIFICATION",
+    "NETWORK_ERROR",
+    "RESOURCE_EXHAUSTED",
+    "INTERNAL_ERROR",
+};
+static_assert(static_cast<int>(webrtc::RTCErrorType::INTERNAL_ERROR) ==
+                  (arraysize(kRTCErrorTypeNames) - 1),
+              "kRTCErrorTypeNames must have as many strings as RTCErrorType "
+              "has values.");
+
+}  // namespace
+
+namespace webrtc {
+
+RTCError::RTCError(RTCError&& other)
+    : type_(other.type_), have_string_message_(other.have_string_message_) {
+  if (have_string_message_) {
+    new (&string_message_) std::string(std::move(other.string_message_));
+  } else {
+    static_message_ = other.static_message_;
+  }
+}
+
+RTCError& RTCError::operator=(RTCError&& other) {
+  type_ = other.type_;
+  if (other.have_string_message_) {
+    set_message(std::move(other.string_message_));
+  } else {
+    set_message(other.static_message_);
+  }
+  return *this;
+}
+
+RTCError::~RTCError() {
+  // If we hold a message string that was built, rather than a static string,
+  // we need to delete it.
+  if (have_string_message_) {
+    string_message_.~basic_string();

[tommi, 2017/02/15 16:27:07]

interesting - did you hit this problem with all tool chains?

[Taylor Brandstetter, 2017/02/15 21:14:20]

I'd only tried with gcc. This might be expected behavior though, since string is
a typedef.

+  }
+}
+
+// static
+RTCError RTCError::OK() {
+  return RTCError();
+}
+
+const char* RTCError::message() const {
+  if (have_string_message_) {
+    return string_message_.c_str();
+  } else {
+    return static_message_;
+  }
+}
+
+void RTCError::set_message(const char* message) {
+  if (have_string_message_) {
+    string_message_.~basic_string();
+    have_string_message_ = false;
+  }
+  static_message_ = message;
+}
+
+void RTCError::set_message(std::string&& message) {
+  if (!have_string_message_) {
+    new (&string_message_) std::string(std::move(message));
+    have_string_message_ = true;
+  } else {
+    string_message_ = message;
+  }
+}
+
+std::ostream& operator<<(std::ostream& stream, RTCErrorType error) {
+  int index = static_cast<int>(error);
+  return stream << kRTCErrorTypeNames[index];
+}
+
+webrtc::RTCError CreateAndLogError(webrtc::RTCErrorType type,
+                                   std::string&& message,
+                                   rtc::LoggingSeverity severity) {
+  // "No error" shouldn't be logged as an error.
+  RTC_DCHECK(type != RTCErrorType::NONE);
+  rtc::LogMessage(__FILE__, __LINE__, severity).stream() << message << " ("
+                                                         << type << ")";
+  return webrtc::RTCError(type, std::move(message));
+}
+
+webrtc::RTCError CreateAndLogError(webrtc::RTCErrorType type,
+                                   const char* message,
+                                   rtc::LoggingSeverity severity) {
+  // "No error" shouldn't be logged as an error.
+  RTC_DCHECK(type != RTCErrorType::NONE);
+  rtc::LogMessage(__FILE__, __LINE__, severity).stream() << message << " ("
+                                                         << type << ")";
+  return webrtc::RTCError(type, message);
+}
+
+webrtc::RTCError CreateAndLogError(webrtc::RTCErrorType type,
+                                   const char* message) {
+  return CreateAndLogError(type, message, rtc::LS_ERROR);
+}
+
+webrtc::RTCError CreateAndLogError(webrtc::RTCErrorType type,
+                                   std::string&& message) {
+  return CreateAndLogError(type, std::move(message), rtc::LS_ERROR);
+}
+
+}  // namespace webrtc