xapian-core/net/serialise-error.cc

   1 /** @file serialise-error.cc
   2  * @brief functions to convert Xapian::Error objects to strings and back
   3  */
   4 /* Copyright (C) 2006,2007,2008,2009,2010,2011,2014,2015,2016 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22
  23 #include <xapian/error.h>
  24
  25 #include "length.h"
  26 #include "serialise-error.h"
  27
  28 #include <string>
  29
  30 using namespace std;
  31
  32 string
  33 serialise_error(const Xapian::Error &e)
  34 {
  35     // The byte before the type name is the type code.
  36     string result(1, (e.get_type())[-1]);
  37     result += encode_length(e.get_context().length());
  38     result += e.get_context();
  39     result += encode_length(e.get_msg().length());
  40     result += e.get_msg();
  41     // The "error string" goes last so we don't need to store its length.
  42     const char * err = e.get_error_string();
  43     if (err) result += err;
  44     return result;
  45 }
  46
  47 void
  48 unserialise_error(const string &serialised_error, const string &prefix,
  49                   const string &new_context)
  50 {
  51     // Use c_str() so last string is nul-terminated.
  52     const char * p = serialised_error.c_str();
  53     const char * end = p + serialised_error.size();
  54     if (p != end) {
  55         char type = *p++;
  56
  57         size_t len;
  58         decode_length_and_check(&p, end, len);
  59         string context(p, len);
  60         p += len;
  61
  62         decode_length_and_check(&p, end, len);
  63         string msg(prefix);
  64         msg.append(p, len);
  65         p += len;
  66
  67         const char * error_string = (p == end) ? NULL : p;
  68
  69         if (!new_context.empty()) {
  70             if (!context.empty()) {
  71                 msg += "; context was: ";
  72                 msg += context;
  73             }
  74             context = new_context;
  75         }
  76
  77         switch (type) {
  78 #include "xapian/errordispatch.h"
  79         }
  80     }
  81
  82     throw Xapian::InternalError("Unknown remote exception type", new_context);
  83 }