posix/socket: add a convenience wrapper for sockets

CMakeLists.txt

@@ -84,6 +84,8 @@ list (
     posix/except.hpp
     posix/fd.cpp
     posix/fd.hpp
+    posix/socket.cpp
+    posix/socket.hpp
 )
 
 

posix/socket.cpp

@@ -0,0 +1,123 @@
+/*
+ * 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.
+ *
+ * Copyright 2017 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "socket.hpp"
+
+#include "except.hpp"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+
+using util::posix::socket;
+
+
+///////////////////////////////////////////////////////////////////////////////
+class lookup {
+public:
+    lookup (const util::view<const char*> host, int port):
+        m_addresses (nullptr, freeaddrinfo)
+    {
+        struct ::addrinfo hints {};
+        hints.ai_family = AF_UNSPEC;
+        hints.ai_socktype = SOCK_STREAM;
+
+        const struct {
+            std::string host;
+            std::string port;
+        } strings {
+            .host = std::string (std::begin (host), std::end (host)),
+            .port = std::to_string (port)
+        };
+
+        addrinfo* _addresses;
+        util::posix::eai::try_code (
+            getaddrinfo (
+                strings.host.c_str (),
+                strings.port.c_str (),
+                &hints,
+                &_addresses
+            )
+        );
+
+        m_addresses.reset (_addresses);
+    };
+
+    auto begin (void) const { return m_addresses.get (); }
+    auto end   (void) const { return nullptr; }
+
+private:
+    std::unique_ptr<addrinfo[],void(*)(addrinfo*)> m_addresses;
+};
+
+
+///////////////////////////////////////////////////////////////////////////////
+static util::posix::fd
+connect_host (const util::view<const char*> host, int port)
+{
+    for (const auto &info: lookup { host, port }) {
+        util::posix::fd sock {
+            socket (info.ai_family, info.ai_socktype, info.ai_protocol)
+        };
+        if (sock == -1)
+            continue;
+
+        if (connect (sock, info.ai_addr, info.ai_addrlen))
+            continue;
+
+        return sock;
+    }
+
+    throw std::runtime_error ("unable to connect");
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+socket::socket (int domain, int type):
+    socket (domain, type, 0)
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+socket::socket (int domain, int type, int protocol):
+    fd (::socket (domain, type, protocol))
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+socket::socket (util::view<const char*> host, int port):
+    fd (connect_host (host, port))
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+socket::~socket ()
+{ ; }
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+socket::connect (util::view<const char*> host, int port)
+{
+    for (const auto &info: lookup { host, port }) {
+        if (!::connect (*this, info.ai_addr, info.ai_addrlen))
+            return;
+    }
+
+    throw std::runtime_error ("unable to reconnect");
+}

posix/socket.hpp

@@ -0,0 +1,60 @@
+/*
+ * 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.
+ *
+ * Copyright 2017 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef CRUFT_UTIL_POSIX_SOCKET_HPP
+#define CRUFT_UTIL_POSIX_SOCKET_HPP
+
+#include "fd.hpp"
+
+#include "except.hpp"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+
+namespace util::posix {
+     class socket : public fd {
+     public:
+         socket (int domain, int type);
+         socket (int domain, int type, int protocol);
+
+         socket (util::view<const char*> host, int port);
+
+         void connect (util::view<const char*> host, int port);
+
+         // the destructor is provided so that we can operate more cleanly on
+         // win32 where we must call closesocket instead of the normal close.
+         // because windows...
+         ~socket ();
+
+         void shutdown ();
+
+         template <typename ValueT>
+         void setoption (int _level, int _name, const ValueT &_value)
+         {
+            error::try_code (
+                setsockopt (
+                    native (),
+                    _level,
+                    _name,
+                    &_value, sizeof (_value)
+                )
+            );
+         }
+     };
+};
+
+#endif