AsyncSocket

Summary:
Move async socket to folly.

Changes:
* Made an AsyncSocketException type instead of TTransportException: Some of the exceptions didn't fit nicely in to std::exception types (like TIMED_OUT).  There are some wrappers in thrift/lib/cpp/async to convert back to TTransportException, so all existing code still compiles.
* Moved read/write callbacks out of AsyncTransport: filters are going to want to do the read/write stuff separately (see revproxy/tunnel/filters, and discussions in D1483148).

Test Plan:
fbconfig -r thrift; fbmake runtests
contbuild should catch everything else - exception types shouldn't change for existing code

Reviewed By: dcsommer@fb.com

Subscribers: mshneer, folly-diffs@, trunkagent, doug, alandau, bmatheny, njormrod, fugalh, jsedgwick

FB internal diff: D1587625

folly/Makefile.am

@@ -131,6 +131,7 @@ nobase_follyinclude_HEADERS = \
 	io/ShutdownSocketSet.h \
 	io/async/AsyncTimeout.h \
 	io/async/AsyncServerSocket.h \
+	io/async/AsyncSocket.h \
 	io/async/DelayedDestruction.h \
 	io/async/EventBase.h \
 	io/async/EventBaseManager.h \
@@ -258,6 +259,7 @@ libfolly_la_SOURCES = \
 	io/ShutdownSocketSet.cpp \
 	io/async/AsyncTimeout.cpp \
 	io/async/AsyncServerSocket.cpp \
+	io/async/AsyncSocket.cpp \
 	io/async/EventBase.cpp \
 	io/async/EventBaseManager.cpp \
 	io/async/EventHandler.cpp \

folly/io/async/AsyncSocketException.h

+/*
+ * Copyright 2014 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <folly/io/async/DelayedDestruction.h>
+
+namespace folly {
+
+class AsyncSocketException : public std::runtime_error {
+ public:
+  enum AsyncSocketExceptionType
+  { UNKNOWN = 0
+  , NOT_OPEN = 1
+  , ALREADY_OPEN = 2
+  , TIMED_OUT = 3
+  , END_OF_FILE = 4
+  , INTERRUPTED = 5
+  , BAD_ARGS = 6
+  , CORRUPTED_DATA = 7
+  , INTERNAL_ERROR = 8
+  , NOT_SUPPORTED = 9
+  , INVALID_STATE = 10
+  , SSL_ERROR = 12
+  , COULD_NOT_BIND = 13
+  , SASL_HANDSHAKE_TIMEOUT = 14
+  };
+
+  AsyncSocketException(
+    AsyncSocketExceptionType type, const std::string& message) :
+      std::runtime_error(message),
+      type_(type), errno_(0) {}
+
+  /** Error code */
+  AsyncSocketExceptionType type_;
+
+  /** A copy of the errno. */
+  int errno_;
+
+  AsyncSocketException(AsyncSocketExceptionType type,
+                      const std::string& message,
+                      int errno_copy) :
+      std::runtime_error(getMessage(message, errno_copy)),
+      type_(type), errno_(errno_copy) {}
+
+  AsyncSocketExceptionType getType() const noexcept { return type_; }
+  int getErrno() const noexcept { return errno_; }
+
+ protected:
+  /** Just like strerror_r but returns a C++ string object. */
+  std::string strerror_s(int errno_copy) {
+    return "errno = " + folly::to<std::string>(errno_copy);
+  }
+
+  /** Return a message based on the input. */
+  std::string getMessage(const std::string &message,
+                                int errno_copy) {
+    if (errno_copy != 0) {
+      return message + ": " + strerror_s(errno_copy);
+    } else {
+      return message;
+    }
+  }
+};
+
+} // folly