Don't catch unknown exceptions if we are only going to rethrow them.
[libt2n] / src / command_client.cpp
index a603634..5d618b2 100644 (file)
@@ -1,21 +1,24 @@
-/***************************************************************************
- *   Copyright (C) 2006 by Gerd v. Egidy                                   *
- *   gve@intra2net.com                                                     *
- *                                                                         *
- *   This library is free software; you can redistribute it and/or modify  *
- *   it under the terms of the GNU Lesser General Public License version   *
- *   2.1 as published by the Free Software Foundation.                     *
- *                                                                         *
- *   This library is distributed in the hope that it will be useful,       *
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
- *   GNU Lesser General Public License for more details.                   *
- *                                                                         *
- *   You should have received a copy of the GNU Lesser General Public      *
- *   License along with this program; if not, write to the                 *
- *   Free Software Foundation, Inc.,                                       *
- *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
- ***************************************************************************/
+/*
+Copyright (C) 2006 by Intra2net AG - Gerd v. Egidy
+
+The software in this package is distributed under the GNU General
+Public License version 2 (with a special exception described below).
+
+A copy of GNU General Public License (GPL) is included in this distribution,
+in the file COPYING.GPL.
+
+As a special exception, if other files instantiate templates or use macros
+or inline functions from this file, or you compile this file and link it
+with other works to produce a work based on this file, this file
+does not by itself cause the resulting work to be covered
+by the GNU General Public License.
+
+However the source code for this file must still be made available
+in accordance with section (3) of the GNU General Public License.
+
+This exception does not invalidate any other reasons why a work based
+on this file might be covered by the GNU General Public License.
+*/
 
 #include <string>
 #include <sstream>
 #include <boost/archive/xml_iarchive.hpp>
 #include <boost/serialization/serialization.hpp>
 
+#include <boost/bind.hpp>
+
 #include "command_client.hxx"
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 using namespace std;
 
 namespace libt2n
 {
 
+/**
+ * Constructor
+ * @param _c connection for this command. Ownership of the pointer is outside.
+ * @param _command_timeout_usec timeout until the command has to be completed
+ * @param _hello_timeout_usec timeout until hello has to be received
+ */
+command_client::command_client(client_connection* _c, long long _command_timeout_usec, long long _hello_timeout_usec)
+    : c(_c)
+    , constructorException(NULL)
+{
+    command_timeout_usec=_command_timeout_usec;
+    hello_timeout_usec=_hello_timeout_usec;
+
+    // for reconnects
+    c->add_callback(new_connection,bind(&command_client::read_hello, boost::ref(*this)));
+
+    // don't expect hello from an always closed connection (like dummy_client_connection)
+    if (!is_connection_closed())
+    {
+        try
+        {
+            read_hello();
+        }
+        catch (t2n_communication_error &e)
+        {
+            c->close();
+
+            // store a copy of the exception that you can find out details about the error later
+            constructorException = e.clone();
+        }
+    }
+}
+
+/**
+ * Destructor
+ */
+command_client::~command_client()
+{
+    if (constructorException)
+    {
+        delete constructorException;
+        constructorException = NULL;
+    }
+}
+
+/** @brief replace the connection currently in use with a new one
+    @param _c pointer to the new connection
+
+    @note the old connection must still be valid when this method is called,
+          it can safely be deleted after this method returned
+
+    @note all callbacks registered on the old connection will be copied over
+          to the new one
+*/
+void command_client::replace_connection(client_connection* _c)
+{
+    // copy all callbacks registered on the old connection
+    for(callback_event_type e=static_cast<callback_event_type>(0);
+        e < __events_end;
+        e=static_cast<callback_event_type>(static_cast<int>(e)+1))
+    {
+        list<boost::function<void ()> > evcb=c->get_callback_list(e);
+
+        for (list<boost::function<void ()> >::iterator i=evcb.begin(); i != evcb.end(); i++)
+            _c->add_callback(e,*i);
+    }
+
+    // replace the connection
+    c=_c;
+
+    read_hello();
+}
+
+/** @brief return a complete packet
+    @param usec_timeout maximum microseconds to wait until the packet is complete
+    @retval packet data as std::string
+
+    @note throws a t2n_transfer_error if the timeout is exceeded
+*/
+std::string command_client::read_packet(const long long &usec_timeout)
+{
+    string resultpacket;
+    bool got_packet=false;
+    long long my_timeout=usec_timeout;
+    while(!(got_packet=c->get_packet(resultpacket)) && my_timeout > 0  && !c->is_closed())
+        c->fill_buffer(my_timeout,&my_timeout);
+
+    if (!got_packet)
+        throw t2n_transfer_error("timeout exceeded");
+
+    return resultpacket;
+}
+
+/** @brief read and check the hello message at the beginning of a connection
+
+    @note throws exceptions if something went wrong
+*/
+void command_client::read_hello()
+{
+    string resultpacket;
+    bool got_packet=false;
+    long long my_timeout=hello_timeout_usec;
+    while(!(got_packet=c->get_packet(resultpacket)) && my_timeout > 0  && !c->is_closed())
+    {
+        c->fill_buffer(my_timeout,&my_timeout);
+
+        c->peek_packet(resultpacket);
+        check_hello(resultpacket);           // will throw before timeout if wrong data received
+    }
+
+    if (!got_packet)
+        throw t2n_transfer_error("timeout exceeded");
+
+    if (!check_hello(resultpacket))
+        throw t2n_version_mismatch("illegal hello received (incomplete): "+resultpacket);
+}
+
+/** @brief check if a hello message is valid
+    @param hellostr std::string with the message to check
+    @retval true if the hello is good and complete
+
+    @note you can check incomplete hellos. you will get a false return value
+          but no exception. throws exceptions as soon as something is wrong.
+*/
+bool command_client::check_hello(const std::string& hellostr)
+{
+    istringstream hello(hellostr);
+
+    char chk;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'T')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != '2')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'N')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != 'v')
+            throw t2n_version_mismatch("illegal hello received (T2N)");
+    }
+    else
+        return false;
+
+    int prot_version;
+    if (hello >> prot_version)
+    {
+        if (prot_version != PROTOCOL_VERSION)
+            throw t2n_version_mismatch("not compatible with the server protocol version");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != ';')
+            throw t2n_version_mismatch("illegal hello received (1. ;)");
+    }
+    else
+        return false;
+
+    unsigned int hbo;
+    if (hello.read((char*)&hbo,sizeof(hbo)))
+    {
+        if (hbo != 1)
+            throw t2n_version_mismatch("host byte order not matching");
+    }
+    else
+        return false;
+
+    if (hello.read(&chk,1))
+    {
+        if (chk != ';')
+            throw t2n_version_mismatch("illegal hello received (2. ;)");
+    }
+    else
+        return false;
+
+    return true;
+}
+
+/** @brief send a command to the server and store the result
+    @param cmd pointer to a command-object
+    @param[out] res result container to store the result in
+
+    @note you can check incomplete hellos. you will get a false return value
+          but no exception. throws exceptions as soon as something is wrong.
+*/
 void command_client::send_command(command* cmd, result_container &res)
 {
     ostringstream ofs;
     command_container cc(cmd);
     boost::archive::binary_oarchive oa(ofs);
 
-    // TODO: exceptions
-    oa << cc;
+    if (is_connection_closed())
+        throw t2n_transfer_error("connection to server is closed");
+
+    try
+    {
+        oa << cc;
+    }
+    catch(boost::archive::archive_exception &e)
+    {
+        ostringstream msg;
+        msg << "archive_exception while serializing on client-side, code " << e.code << " (" << e.what() << ")";
+        throw t2n_serialization_error(msg.str());
+    }
 
     std::ostream* ostr;
-    if ((ostr=c.get_logstream(fulldebug))!=NULL)
+    if ((ostr=c->get_logstream(fulldebug))!=NULL)
     {
         (*ostr) << "sending command, decoded data: " << std::endl;
         boost::archive::xml_oarchive xo(*ostr);
         xo << BOOST_SERIALIZATION_NVP(cc);
-    }
+   }
 
-    c.write(ofs.str());
+    c->write(ofs.str());
 
-    // TODO: fix timeout
-    string resultpacket;
-    while(!c.get_packet(resultpacket))
-        c.fill_buffer();
-
-    istringstream ifs(resultpacket);
+    istringstream ifs(read_packet(command_timeout_usec));
     boost::archive::binary_iarchive ia(ifs);
 
-    // TODO: exceptions
-    ia >> res;
+    try
+    {
+        ia >> res;
+    }
+    catch(boost::archive::archive_exception &e)
+    {
+        ostringstream msg;
+        msg << "archive_exception while deserializing on client-side, code " << e.code << " (" << e.what() << ")";
+        throw t2n_serialization_error(msg.str());
+    }
 
-    if ((ostr=c.get_logstream(fulldebug))!=NULL)
+    if ((ostr=c->get_logstream(fulldebug))!=NULL)
     {
         (*ostr) << "received result, decoded data: " << std::endl;
         boost::archive::xml_oarchive xo(*ostr);