Adding RTCErrorOr class to be used by ORTC APIs.

webrtc/api/rtcerror.cc

Index: webrtc/api/rtcerror.cc
diff --git a/webrtc/api/rtcerror.cc b/webrtc/api/rtcerror.cc
new file mode 100644
index 0000000000000000000000000000000000000000..15a3f2919107d4f29c8cdb84a26b761a3af21c51
--- /dev/null
+++ b/webrtc/api/rtcerror.cc
@@ -0,0 +1,101 @@
+/*
+ *  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();
+  }
+}
+
+// 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];
+}
+
+}  // namespace webrtc