xapian-core/api/error.cc

   1 /** @file error.cc
   2  *  @brief Xapian::Error base class.
   3  */
   4 /* Copyright (C) 2007,2008,2011,2013,2014,2015 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (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 "safeerrno.h"
  26 #ifdef __WIN32__
  27 # include "safewindows.h"
  28 #else
  29 # include "safenetdb.h"
  30 #endif
  31
  32 #include <cstdlib> // For abs().
  33 #include <cstring> // For memcmp().
  34
  35 #include "errno_to_string.h"
  36 #include "str.h"
  37 #include "unicode/description_append.h"
  38
  39 using namespace std;
  40
  41 Xapian::Error::Error(const std::string &msg_, const std::string &context_,
  42                      const char * type_, const char * error_string_)
  43     : msg(msg_), context(context_), error_string(), type(type_),
  44       my_errno(0), already_handled(false)
  45 {
  46     if (error_string_) error_string.assign(error_string_);
  47 }
  48
  49 const char *
  50 Xapian::Error::get_error_string() const
  51 {
  52     if (error_string.empty()) {
  53         if (my_errno == 0) return NULL;
  54 #ifdef __WIN32__
  55         if (my_errno < 0 || my_errno >= WSABASEERR) {
  56             int e = abs(my_errno);
  57             DWORD len;
  58             char * error;
  59             len = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM|
  60                                 FORMAT_MESSAGE_ALLOCATE_BUFFER,
  61                                 0, e, 0, (CHAR*)&error, 0, 0);
  62             if (error) {
  63                 // Remove any trailing \r\n from output of FormatMessage.
  64                 if (len >= 2 && memcmp(error + len - 2, "\r\n", 2) == 0)
  65                     len -= 2;
  66                 error_string.assign(error, len);
  67                 LocalFree(error);
  68             } else {
  69                 error_string = "Unknown Error ";
  70                 error_string += str(e);
  71             }
  72         } else {
  73             errno_to_string(my_errno, error_string);
  74         }
  75 #else
  76         if (my_errno > 0) {
  77             errno_to_string(my_errno, error_string);
  78         } else {
  79             // POSIX says only that EAI_* constants are "non-zero" - they're
  80             // negative on Linux, but we allow for them being positive.  We
  81             // check they all that the same sign in net/remoteconnection.h.
  82             if (EAI_FAIL > 0)
  83                 error_string.assign(gai_strerror(-my_errno));
  84             else
  85                 error_string.assign(gai_strerror(my_errno));
  86         }
  87 #endif
  88     }
  89     return error_string.c_str();
  90 }
  91
  92 string
  93 Xapian::Error::get_description() const
  94 {
  95     string desc(get_type());
  96     desc += ": ";
  97     desc += msg;
  98     if (!context.empty()) {
  99         desc += " (context: ";
 100         description_append(desc, context);
 101         desc += ')';
 102     }
 103     const char *e = get_error_string();
 104     if (e) {
 105         desc += " (";
 106         description_append(desc, e);
 107         desc += ')';
 108     }
 109     return desc;
 110 }